Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/buffer.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992, 2002 Linus Torvalds |
| 5 | */ |
| 6 | |
| 7 | /* |
| 8 | * Start bdflush() with kernel_thread not syscall - Paul Gortmaker, 12/95 |
| 9 | * |
| 10 | * Removed a lot of unnecessary code and simplified things now that |
| 11 | * the buffer cache isn't our primary cache - Andrew Tridgell 12/96 |
| 12 | * |
| 13 | * Speed up hash, lru, and free list operations. Use gfp() for allocating |
| 14 | * hash table, use SLAB cache for buffer heads. SMP threading. -DaveM |
| 15 | * |
| 16 | * Added 32k buffer block sizes - these are required older ARM systems. - RMK |
| 17 | * |
| 18 | * async buffer flushing, 1999 Andrea Arcangeli <andrea@suse.de> |
| 19 | */ |
| 20 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | #include <linux/kernel.h> |
| 22 | #include <linux/syscalls.h> |
| 23 | #include <linux/fs.h> |
| 24 | #include <linux/mm.h> |
| 25 | #include <linux/percpu.h> |
| 26 | #include <linux/slab.h> |
Randy Dunlap | 16f7e0f | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 27 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | #include <linux/blkdev.h> |
| 29 | #include <linux/file.h> |
| 30 | #include <linux/quotaops.h> |
| 31 | #include <linux/highmem.h> |
| 32 | #include <linux/module.h> |
| 33 | #include <linux/writeback.h> |
| 34 | #include <linux/hash.h> |
| 35 | #include <linux/suspend.h> |
| 36 | #include <linux/buffer_head.h> |
Andrew Morton | 55e829a | 2006-12-10 02:19:27 -0800 | [diff] [blame] | 37 | #include <linux/task_io_accounting_ops.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | #include <linux/bio.h> |
| 39 | #include <linux/notifier.h> |
| 40 | #include <linux/cpu.h> |
| 41 | #include <linux/bitops.h> |
| 42 | #include <linux/mpage.h> |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 43 | #include <linux/bit_spinlock.h> |
Dan Magenheimer | c515e1f | 2011-05-26 10:01:43 -0600 | [diff] [blame] | 44 | #include <linux/cleancache.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | |
| 46 | static int fsync_buffers_list(spinlock_t *lock, struct list_head *list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | |
| 48 | #define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers) |
| 49 | |
| 50 | inline void |
| 51 | init_buffer(struct buffer_head *bh, bh_end_io_t *handler, void *private) |
| 52 | { |
| 53 | bh->b_end_io = handler; |
| 54 | bh->b_private = private; |
| 55 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 56 | EXPORT_SYMBOL(init_buffer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | |
Jens Axboe | 7eaceac | 2011-03-10 08:52:07 +0100 | [diff] [blame] | 58 | static int sleep_on_buffer(void *word) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | io_schedule(); |
| 61 | return 0; |
| 62 | } |
| 63 | |
Harvey Harrison | fc9b52c | 2008-02-08 04:19:52 -0800 | [diff] [blame] | 64 | void __lock_buffer(struct buffer_head *bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 65 | { |
Jens Axboe | 7eaceac | 2011-03-10 08:52:07 +0100 | [diff] [blame] | 66 | wait_on_bit_lock(&bh->b_state, BH_Lock, sleep_on_buffer, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | TASK_UNINTERRUPTIBLE); |
| 68 | } |
| 69 | EXPORT_SYMBOL(__lock_buffer); |
| 70 | |
Harvey Harrison | fc9b52c | 2008-02-08 04:19:52 -0800 | [diff] [blame] | 71 | void unlock_buffer(struct buffer_head *bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | { |
Nick Piggin | 51b07fc | 2008-10-18 20:27:00 -0700 | [diff] [blame] | 73 | clear_bit_unlock(BH_Lock, &bh->b_state); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | smp_mb__after_clear_bit(); |
| 75 | wake_up_bit(&bh->b_state, BH_Lock); |
| 76 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 77 | EXPORT_SYMBOL(unlock_buffer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | |
| 79 | /* |
| 80 | * Block until a buffer comes unlocked. This doesn't stop it |
| 81 | * from becoming locked again - you have to lock it yourself |
| 82 | * if you want to preserve its state. |
| 83 | */ |
| 84 | void __wait_on_buffer(struct buffer_head * bh) |
| 85 | { |
Jens Axboe | 7eaceac | 2011-03-10 08:52:07 +0100 | [diff] [blame] | 86 | wait_on_bit(&bh->b_state, BH_Lock, sleep_on_buffer, TASK_UNINTERRUPTIBLE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 88 | EXPORT_SYMBOL(__wait_on_buffer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | |
| 90 | static void |
| 91 | __clear_page_buffers(struct page *page) |
| 92 | { |
| 93 | ClearPagePrivate(page); |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 94 | set_page_private(page, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | page_cache_release(page); |
| 96 | } |
| 97 | |
Keith Mannthey | 08bafc0 | 2008-11-25 10:24:35 +0100 | [diff] [blame] | 98 | |
| 99 | static int quiet_error(struct buffer_head *bh) |
| 100 | { |
| 101 | if (!test_bit(BH_Quiet, &bh->b_state) && printk_ratelimit()) |
| 102 | return 0; |
| 103 | return 1; |
| 104 | } |
| 105 | |
| 106 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 107 | static void buffer_io_error(struct buffer_head *bh) |
| 108 | { |
| 109 | char b[BDEVNAME_SIZE]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 110 | printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n", |
| 111 | bdevname(bh->b_bdev, b), |
| 112 | (unsigned long long)bh->b_blocknr); |
| 113 | } |
| 114 | |
| 115 | /* |
Dmitry Monakhov | 68671f3 | 2007-10-16 01:24:47 -0700 | [diff] [blame] | 116 | * End-of-IO handler helper function which does not touch the bh after |
| 117 | * unlocking it. |
| 118 | * Note: unlock_buffer() sort-of does touch the bh after unlocking it, but |
| 119 | * a race there is benign: unlock_buffer() only use the bh's address for |
| 120 | * hashing after unlocking the buffer, so it doesn't actually touch the bh |
| 121 | * itself. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | */ |
Dmitry Monakhov | 68671f3 | 2007-10-16 01:24:47 -0700 | [diff] [blame] | 123 | static void __end_buffer_read_notouch(struct buffer_head *bh, int uptodate) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | { |
| 125 | if (uptodate) { |
| 126 | set_buffer_uptodate(bh); |
| 127 | } else { |
| 128 | /* This happens, due to failed READA attempts. */ |
| 129 | clear_buffer_uptodate(bh); |
| 130 | } |
| 131 | unlock_buffer(bh); |
Dmitry Monakhov | 68671f3 | 2007-10-16 01:24:47 -0700 | [diff] [blame] | 132 | } |
| 133 | |
| 134 | /* |
| 135 | * Default synchronous end-of-IO handler.. Just mark it up-to-date and |
| 136 | * unlock the buffer. This is what ll_rw_block uses too. |
| 137 | */ |
| 138 | void end_buffer_read_sync(struct buffer_head *bh, int uptodate) |
| 139 | { |
| 140 | __end_buffer_read_notouch(bh, uptodate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 141 | put_bh(bh); |
| 142 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 143 | EXPORT_SYMBOL(end_buffer_read_sync); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | |
| 145 | void end_buffer_write_sync(struct buffer_head *bh, int uptodate) |
| 146 | { |
| 147 | char b[BDEVNAME_SIZE]; |
| 148 | |
| 149 | if (uptodate) { |
| 150 | set_buffer_uptodate(bh); |
| 151 | } else { |
Christoph Hellwig | 0edd55f | 2010-08-18 05:29:23 -0400 | [diff] [blame] | 152 | if (!quiet_error(bh)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 153 | buffer_io_error(bh); |
| 154 | printk(KERN_WARNING "lost page write due to " |
| 155 | "I/O error on %s\n", |
| 156 | bdevname(bh->b_bdev, b)); |
| 157 | } |
| 158 | set_buffer_write_io_error(bh); |
| 159 | clear_buffer_uptodate(bh); |
| 160 | } |
| 161 | unlock_buffer(bh); |
| 162 | put_bh(bh); |
| 163 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 164 | EXPORT_SYMBOL(end_buffer_write_sync); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | |
| 166 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 167 | * Various filesystems appear to want __find_get_block to be non-blocking. |
| 168 | * But it's the page lock which protects the buffers. To get around this, |
| 169 | * we get exclusion from try_to_free_buffers with the blockdev mapping's |
| 170 | * private_lock. |
| 171 | * |
| 172 | * Hack idea: for the blockdev mapping, i_bufferlist_lock contention |
| 173 | * may be quite high. This code could TryLock the page, and if that |
| 174 | * succeeds, there is no need to take private_lock. (But if |
| 175 | * private_lock is contended then so is mapping->tree_lock). |
| 176 | */ |
| 177 | static struct buffer_head * |
Coywolf Qi Hunt | 385fd4c | 2005-11-07 00:59:39 -0800 | [diff] [blame] | 178 | __find_get_block_slow(struct block_device *bdev, sector_t block) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | { |
| 180 | struct inode *bd_inode = bdev->bd_inode; |
| 181 | struct address_space *bd_mapping = bd_inode->i_mapping; |
| 182 | struct buffer_head *ret = NULL; |
| 183 | pgoff_t index; |
| 184 | struct buffer_head *bh; |
| 185 | struct buffer_head *head; |
| 186 | struct page *page; |
| 187 | int all_mapped = 1; |
| 188 | |
| 189 | index = block >> (PAGE_CACHE_SHIFT - bd_inode->i_blkbits); |
| 190 | page = find_get_page(bd_mapping, index); |
| 191 | if (!page) |
| 192 | goto out; |
| 193 | |
| 194 | spin_lock(&bd_mapping->private_lock); |
| 195 | if (!page_has_buffers(page)) |
| 196 | goto out_unlock; |
| 197 | head = page_buffers(page); |
| 198 | bh = head; |
| 199 | do { |
Nikanth Karthikesan | 97f76d3 | 2009-04-02 16:56:46 -0700 | [diff] [blame] | 200 | if (!buffer_mapped(bh)) |
| 201 | all_mapped = 0; |
| 202 | else if (bh->b_blocknr == block) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | ret = bh; |
| 204 | get_bh(bh); |
| 205 | goto out_unlock; |
| 206 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 207 | bh = bh->b_this_page; |
| 208 | } while (bh != head); |
| 209 | |
| 210 | /* we might be here because some of the buffers on this page are |
| 211 | * not mapped. This is due to various races between |
| 212 | * file io on the block device and getblk. It gets dealt with |
| 213 | * elsewhere, don't buffer_error if we had some unmapped buffers |
| 214 | */ |
| 215 | if (all_mapped) { |
Tao Ma | 72a2ebd | 2011-10-31 17:09:00 -0700 | [diff] [blame^] | 216 | char b[BDEVNAME_SIZE]; |
| 217 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 218 | printk("__find_get_block_slow() failed. " |
| 219 | "block=%llu, b_blocknr=%llu\n", |
Badari Pulavarty | 205f87f | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 220 | (unsigned long long)block, |
| 221 | (unsigned long long)bh->b_blocknr); |
| 222 | printk("b_state=0x%08lx, b_size=%zu\n", |
| 223 | bh->b_state, bh->b_size); |
Tao Ma | 72a2ebd | 2011-10-31 17:09:00 -0700 | [diff] [blame^] | 224 | printk("device %s blocksize: %d\n", bdevname(bdev, b), |
| 225 | 1 << bd_inode->i_blkbits); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 226 | } |
| 227 | out_unlock: |
| 228 | spin_unlock(&bd_mapping->private_lock); |
| 229 | page_cache_release(page); |
| 230 | out: |
| 231 | return ret; |
| 232 | } |
| 233 | |
| 234 | /* If invalidate_buffers() will trash dirty buffers, it means some kind |
| 235 | of fs corruption is going on. Trashing dirty data always imply losing |
| 236 | information that was supposed to be just stored on the physical layer |
| 237 | by the user. |
| 238 | |
| 239 | Thus invalidate_buffers in general usage is not allwowed to trash |
| 240 | dirty buffers. For example ioctl(FLSBLKBUF) expects dirty data to |
| 241 | be preserved. These buffers are simply skipped. |
| 242 | |
| 243 | We also skip buffers which are still in use. For example this can |
| 244 | happen if a userspace program is reading the block device. |
| 245 | |
| 246 | NOTE: In the case where the user removed a removable-media-disk even if |
| 247 | there's still dirty data not synced on disk (due a bug in the device driver |
| 248 | or due an error of the user), by not destroying the dirty buffers we could |
| 249 | generate corruption also on the next media inserted, thus a parameter is |
| 250 | necessary to handle this case in the most safe way possible (trying |
| 251 | to not corrupt also the new disk inserted with the data belonging to |
| 252 | the old now corrupted disk). Also for the ramdisk the natural thing |
| 253 | to do in order to release the ramdisk memory is to destroy dirty buffers. |
| 254 | |
| 255 | These are two special cases. Normal usage imply the device driver |
| 256 | to issue a sync on the device (without waiting I/O completion) and |
| 257 | then an invalidate_buffers call that doesn't trash dirty buffers. |
| 258 | |
| 259 | For handling cache coherency with the blkdev pagecache the 'update' case |
| 260 | is been introduced. It is needed to re-read from disk any pinned |
| 261 | buffer. NOTE: re-reading from disk is destructive so we can do it only |
| 262 | when we assume nobody is changing the buffercache under our I/O and when |
| 263 | we think the disk contains more recent information than the buffercache. |
| 264 | The update == 1 pass marks the buffers we need to update, the update == 2 |
| 265 | pass does the actual I/O. */ |
Peter Zijlstra | f98393a | 2007-05-06 14:49:54 -0700 | [diff] [blame] | 266 | void invalidate_bdev(struct block_device *bdev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | { |
Andrew Morton | 0e1dfc6 | 2006-07-30 03:03:28 -0700 | [diff] [blame] | 268 | struct address_space *mapping = bdev->bd_inode->i_mapping; |
| 269 | |
| 270 | if (mapping->nrpages == 0) |
| 271 | return; |
| 272 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 273 | invalidate_bh_lrus(); |
Tejun Heo | fa4b907 | 2010-05-15 20:09:27 +0200 | [diff] [blame] | 274 | lru_add_drain_all(); /* make sure all lru add caches are flushed */ |
Andrew Morton | fc0ecff | 2007-02-10 01:45:39 -0800 | [diff] [blame] | 275 | invalidate_mapping_pages(mapping, 0, -1); |
Dan Magenheimer | c515e1f | 2011-05-26 10:01:43 -0600 | [diff] [blame] | 276 | /* 99% of the time, we don't need to flush the cleancache on the bdev. |
| 277 | * But, for the strange corners, lets be cautious |
| 278 | */ |
| 279 | cleancache_flush_inode(mapping); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 281 | EXPORT_SYMBOL(invalidate_bdev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 282 | |
| 283 | /* |
Jens Axboe | 5b0830c | 2009-09-23 19:37:09 +0200 | [diff] [blame] | 284 | * Kick the writeback threads then try to free up some ZONE_NORMAL memory. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 285 | */ |
| 286 | static void free_more_memory(void) |
| 287 | { |
Mel Gorman | 19770b3 | 2008-04-28 02:12:18 -0700 | [diff] [blame] | 288 | struct zone *zone; |
Mel Gorman | 0e88460 | 2008-04-28 02:12:14 -0700 | [diff] [blame] | 289 | int nid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 291 | wakeup_flusher_threads(1024); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 292 | yield(); |
| 293 | |
Mel Gorman | 0e88460 | 2008-04-28 02:12:14 -0700 | [diff] [blame] | 294 | for_each_online_node(nid) { |
Mel Gorman | 19770b3 | 2008-04-28 02:12:18 -0700 | [diff] [blame] | 295 | (void)first_zones_zonelist(node_zonelist(nid, GFP_NOFS), |
| 296 | gfp_zone(GFP_NOFS), NULL, |
| 297 | &zone); |
| 298 | if (zone) |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 299 | try_to_free_pages(node_zonelist(nid, GFP_NOFS), 0, |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 300 | GFP_NOFS, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 301 | } |
| 302 | } |
| 303 | |
| 304 | /* |
| 305 | * I/O completion handler for block_read_full_page() - pages |
| 306 | * which come unlocked at the end of I/O. |
| 307 | */ |
| 308 | static void end_buffer_async_read(struct buffer_head *bh, int uptodate) |
| 309 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 310 | unsigned long flags; |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 311 | struct buffer_head *first; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 312 | struct buffer_head *tmp; |
| 313 | struct page *page; |
| 314 | int page_uptodate = 1; |
| 315 | |
| 316 | BUG_ON(!buffer_async_read(bh)); |
| 317 | |
| 318 | page = bh->b_page; |
| 319 | if (uptodate) { |
| 320 | set_buffer_uptodate(bh); |
| 321 | } else { |
| 322 | clear_buffer_uptodate(bh); |
Keith Mannthey | 08bafc0 | 2008-11-25 10:24:35 +0100 | [diff] [blame] | 323 | if (!quiet_error(bh)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 324 | buffer_io_error(bh); |
| 325 | SetPageError(page); |
| 326 | } |
| 327 | |
| 328 | /* |
| 329 | * Be _very_ careful from here on. Bad things can happen if |
| 330 | * two buffer heads end IO at almost the same time and both |
| 331 | * decide that the page is now completely done. |
| 332 | */ |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 333 | first = page_buffers(page); |
| 334 | local_irq_save(flags); |
| 335 | bit_spin_lock(BH_Uptodate_Lock, &first->b_state); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | clear_buffer_async_read(bh); |
| 337 | unlock_buffer(bh); |
| 338 | tmp = bh; |
| 339 | do { |
| 340 | if (!buffer_uptodate(tmp)) |
| 341 | page_uptodate = 0; |
| 342 | if (buffer_async_read(tmp)) { |
| 343 | BUG_ON(!buffer_locked(tmp)); |
| 344 | goto still_busy; |
| 345 | } |
| 346 | tmp = tmp->b_this_page; |
| 347 | } while (tmp != bh); |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 348 | bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); |
| 349 | local_irq_restore(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 350 | |
| 351 | /* |
| 352 | * If none of the buffers had errors and they are all |
| 353 | * uptodate then we can set the page uptodate. |
| 354 | */ |
| 355 | if (page_uptodate && !PageError(page)) |
| 356 | SetPageUptodate(page); |
| 357 | unlock_page(page); |
| 358 | return; |
| 359 | |
| 360 | still_busy: |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 361 | bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); |
| 362 | local_irq_restore(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 363 | return; |
| 364 | } |
| 365 | |
| 366 | /* |
| 367 | * Completion handler for block_write_full_page() - pages which are unlocked |
| 368 | * during I/O, and which have PageWriteback cleared upon I/O completion. |
| 369 | */ |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 370 | void end_buffer_async_write(struct buffer_head *bh, int uptodate) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 371 | { |
| 372 | char b[BDEVNAME_SIZE]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 373 | unsigned long flags; |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 374 | struct buffer_head *first; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 375 | struct buffer_head *tmp; |
| 376 | struct page *page; |
| 377 | |
| 378 | BUG_ON(!buffer_async_write(bh)); |
| 379 | |
| 380 | page = bh->b_page; |
| 381 | if (uptodate) { |
| 382 | set_buffer_uptodate(bh); |
| 383 | } else { |
Keith Mannthey | 08bafc0 | 2008-11-25 10:24:35 +0100 | [diff] [blame] | 384 | if (!quiet_error(bh)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 385 | buffer_io_error(bh); |
| 386 | printk(KERN_WARNING "lost page write due to " |
| 387 | "I/O error on %s\n", |
| 388 | bdevname(bh->b_bdev, b)); |
| 389 | } |
| 390 | set_bit(AS_EIO, &page->mapping->flags); |
Jan Kara | 58ff407 | 2006-10-17 00:10:19 -0700 | [diff] [blame] | 391 | set_buffer_write_io_error(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | clear_buffer_uptodate(bh); |
| 393 | SetPageError(page); |
| 394 | } |
| 395 | |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 396 | first = page_buffers(page); |
| 397 | local_irq_save(flags); |
| 398 | bit_spin_lock(BH_Uptodate_Lock, &first->b_state); |
| 399 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 400 | clear_buffer_async_write(bh); |
| 401 | unlock_buffer(bh); |
| 402 | tmp = bh->b_this_page; |
| 403 | while (tmp != bh) { |
| 404 | if (buffer_async_write(tmp)) { |
| 405 | BUG_ON(!buffer_locked(tmp)); |
| 406 | goto still_busy; |
| 407 | } |
| 408 | tmp = tmp->b_this_page; |
| 409 | } |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 410 | bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); |
| 411 | local_irq_restore(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 412 | end_page_writeback(page); |
| 413 | return; |
| 414 | |
| 415 | still_busy: |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 416 | bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); |
| 417 | local_irq_restore(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 418 | return; |
| 419 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 420 | EXPORT_SYMBOL(end_buffer_async_write); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 421 | |
| 422 | /* |
| 423 | * If a page's buffers are under async readin (end_buffer_async_read |
| 424 | * completion) then there is a possibility that another thread of |
| 425 | * control could lock one of the buffers after it has completed |
| 426 | * but while some of the other buffers have not completed. This |
| 427 | * locked buffer would confuse end_buffer_async_read() into not unlocking |
| 428 | * the page. So the absence of BH_Async_Read tells end_buffer_async_read() |
| 429 | * that this buffer is not under async I/O. |
| 430 | * |
| 431 | * The page comes unlocked when it has no locked buffer_async buffers |
| 432 | * left. |
| 433 | * |
| 434 | * PageLocked prevents anyone starting new async I/O reads any of |
| 435 | * the buffers. |
| 436 | * |
| 437 | * PageWriteback is used to prevent simultaneous writeout of the same |
| 438 | * page. |
| 439 | * |
| 440 | * PageLocked prevents anyone from starting writeback of a page which is |
| 441 | * under read I/O (PageWriteback is only ever set against a locked page). |
| 442 | */ |
| 443 | static void mark_buffer_async_read(struct buffer_head *bh) |
| 444 | { |
| 445 | bh->b_end_io = end_buffer_async_read; |
| 446 | set_buffer_async_read(bh); |
| 447 | } |
| 448 | |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 449 | static void mark_buffer_async_write_endio(struct buffer_head *bh, |
| 450 | bh_end_io_t *handler) |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 451 | { |
| 452 | bh->b_end_io = handler; |
| 453 | set_buffer_async_write(bh); |
| 454 | } |
| 455 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 456 | void mark_buffer_async_write(struct buffer_head *bh) |
| 457 | { |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 458 | mark_buffer_async_write_endio(bh, end_buffer_async_write); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 459 | } |
| 460 | EXPORT_SYMBOL(mark_buffer_async_write); |
| 461 | |
| 462 | |
| 463 | /* |
| 464 | * fs/buffer.c contains helper functions for buffer-backed address space's |
| 465 | * fsync functions. A common requirement for buffer-based filesystems is |
| 466 | * that certain data from the backing blockdev needs to be written out for |
| 467 | * a successful fsync(). For example, ext2 indirect blocks need to be |
| 468 | * written back and waited upon before fsync() returns. |
| 469 | * |
| 470 | * The functions mark_buffer_inode_dirty(), fsync_inode_buffers(), |
| 471 | * inode_has_buffers() and invalidate_inode_buffers() are provided for the |
| 472 | * management of a list of dependent buffers at ->i_mapping->private_list. |
| 473 | * |
| 474 | * Locking is a little subtle: try_to_free_buffers() will remove buffers |
| 475 | * from their controlling inode's queue when they are being freed. But |
| 476 | * try_to_free_buffers() will be operating against the *blockdev* mapping |
| 477 | * at the time, not against the S_ISREG file which depends on those buffers. |
| 478 | * So the locking for private_list is via the private_lock in the address_space |
| 479 | * which backs the buffers. Which is different from the address_space |
| 480 | * against which the buffers are listed. So for a particular address_space, |
| 481 | * mapping->private_lock does *not* protect mapping->private_list! In fact, |
| 482 | * mapping->private_list will always be protected by the backing blockdev's |
| 483 | * ->private_lock. |
| 484 | * |
| 485 | * Which introduces a requirement: all buffers on an address_space's |
| 486 | * ->private_list must be from the same address_space: the blockdev's. |
| 487 | * |
| 488 | * address_spaces which do not place buffers at ->private_list via these |
| 489 | * utility functions are free to use private_lock and private_list for |
| 490 | * whatever they want. The only requirement is that list_empty(private_list) |
| 491 | * be true at clear_inode() time. |
| 492 | * |
| 493 | * FIXME: clear_inode should not call invalidate_inode_buffers(). The |
| 494 | * filesystems should do that. invalidate_inode_buffers() should just go |
| 495 | * BUG_ON(!list_empty). |
| 496 | * |
| 497 | * FIXME: mark_buffer_dirty_inode() is a data-plane operation. It should |
| 498 | * take an address_space, not an inode. And it should be called |
| 499 | * mark_buffer_dirty_fsync() to clearly define why those buffers are being |
| 500 | * queued up. |
| 501 | * |
| 502 | * FIXME: mark_buffer_dirty_inode() doesn't need to add the buffer to the |
| 503 | * list if it is already on a list. Because if the buffer is on a list, |
| 504 | * it *must* already be on the right one. If not, the filesystem is being |
| 505 | * silly. This will save a ton of locking. But first we have to ensure |
| 506 | * that buffers are taken *off* the old inode's list when they are freed |
| 507 | * (presumably in truncate). That requires careful auditing of all |
| 508 | * filesystems (do it inside bforget()). It could also be done by bringing |
| 509 | * b_inode back. |
| 510 | */ |
| 511 | |
| 512 | /* |
| 513 | * The buffer's backing address_space's private_lock must be held |
| 514 | */ |
Thomas Petazzoni | dbacefc | 2008-07-29 22:33:47 -0700 | [diff] [blame] | 515 | static void __remove_assoc_queue(struct buffer_head *bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 516 | { |
| 517 | list_del_init(&bh->b_assoc_buffers); |
Jan Kara | 58ff407 | 2006-10-17 00:10:19 -0700 | [diff] [blame] | 518 | WARN_ON(!bh->b_assoc_map); |
| 519 | if (buffer_write_io_error(bh)) |
| 520 | set_bit(AS_EIO, &bh->b_assoc_map->flags); |
| 521 | bh->b_assoc_map = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 522 | } |
| 523 | |
| 524 | int inode_has_buffers(struct inode *inode) |
| 525 | { |
| 526 | return !list_empty(&inode->i_data.private_list); |
| 527 | } |
| 528 | |
| 529 | /* |
| 530 | * osync is designed to support O_SYNC io. It waits synchronously for |
| 531 | * all already-submitted IO to complete, but does not queue any new |
| 532 | * writes to the disk. |
| 533 | * |
| 534 | * To do O_SYNC writes, just queue the buffer writes with ll_rw_block as |
| 535 | * you dirty the buffers, and then use osync_inode_buffers to wait for |
| 536 | * completion. Any other dirty buffers which are not yet queued for |
| 537 | * write will not be flushed to disk by the osync. |
| 538 | */ |
| 539 | static int osync_buffers_list(spinlock_t *lock, struct list_head *list) |
| 540 | { |
| 541 | struct buffer_head *bh; |
| 542 | struct list_head *p; |
| 543 | int err = 0; |
| 544 | |
| 545 | spin_lock(lock); |
| 546 | repeat: |
| 547 | list_for_each_prev(p, list) { |
| 548 | bh = BH_ENTRY(p); |
| 549 | if (buffer_locked(bh)) { |
| 550 | get_bh(bh); |
| 551 | spin_unlock(lock); |
| 552 | wait_on_buffer(bh); |
| 553 | if (!buffer_uptodate(bh)) |
| 554 | err = -EIO; |
| 555 | brelse(bh); |
| 556 | spin_lock(lock); |
| 557 | goto repeat; |
| 558 | } |
| 559 | } |
| 560 | spin_unlock(lock); |
| 561 | return err; |
| 562 | } |
| 563 | |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 564 | static void do_thaw_one(struct super_block *sb, void *unused) |
| 565 | { |
| 566 | char b[BDEVNAME_SIZE]; |
| 567 | while (sb->s_bdev && !thaw_bdev(sb->s_bdev, sb)) |
| 568 | printk(KERN_WARNING "Emergency Thaw on %s\n", |
| 569 | bdevname(sb->s_bdev, b)); |
| 570 | } |
| 571 | |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 572 | static void do_thaw_all(struct work_struct *work) |
Eric Sandeen | c2d7543 | 2009-03-31 15:23:46 -0700 | [diff] [blame] | 573 | { |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 574 | iterate_supers(do_thaw_one, NULL); |
Jens Axboe | 053c525 | 2009-04-08 13:44:08 +0200 | [diff] [blame] | 575 | kfree(work); |
Eric Sandeen | c2d7543 | 2009-03-31 15:23:46 -0700 | [diff] [blame] | 576 | printk(KERN_WARNING "Emergency Thaw complete\n"); |
| 577 | } |
| 578 | |
| 579 | /** |
| 580 | * emergency_thaw_all -- forcibly thaw every frozen filesystem |
| 581 | * |
| 582 | * Used for emergency unfreeze of all filesystems via SysRq |
| 583 | */ |
| 584 | void emergency_thaw_all(void) |
| 585 | { |
Jens Axboe | 053c525 | 2009-04-08 13:44:08 +0200 | [diff] [blame] | 586 | struct work_struct *work; |
| 587 | |
| 588 | work = kmalloc(sizeof(*work), GFP_ATOMIC); |
| 589 | if (work) { |
| 590 | INIT_WORK(work, do_thaw_all); |
| 591 | schedule_work(work); |
| 592 | } |
Eric Sandeen | c2d7543 | 2009-03-31 15:23:46 -0700 | [diff] [blame] | 593 | } |
| 594 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 595 | /** |
Randy Dunlap | 78a4a50 | 2008-02-29 22:02:31 -0800 | [diff] [blame] | 596 | * sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 597 | * @mapping: the mapping which wants those buffers written |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 598 | * |
| 599 | * Starts I/O against the buffers at mapping->private_list, and waits upon |
| 600 | * that I/O. |
| 601 | * |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 602 | * Basically, this is a convenience function for fsync(). |
| 603 | * @mapping is a file or directory which needs those buffers to be written for |
| 604 | * a successful fsync(). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 605 | */ |
| 606 | int sync_mapping_buffers(struct address_space *mapping) |
| 607 | { |
| 608 | struct address_space *buffer_mapping = mapping->assoc_mapping; |
| 609 | |
| 610 | if (buffer_mapping == NULL || list_empty(&mapping->private_list)) |
| 611 | return 0; |
| 612 | |
| 613 | return fsync_buffers_list(&buffer_mapping->private_lock, |
| 614 | &mapping->private_list); |
| 615 | } |
| 616 | EXPORT_SYMBOL(sync_mapping_buffers); |
| 617 | |
| 618 | /* |
| 619 | * Called when we've recently written block `bblock', and it is known that |
| 620 | * `bblock' was for a buffer_boundary() buffer. This means that the block at |
| 621 | * `bblock + 1' is probably a dirty indirect block. Hunt it down and, if it's |
| 622 | * dirty, schedule it for IO. So that indirects merge nicely with their data. |
| 623 | */ |
| 624 | void write_boundary_block(struct block_device *bdev, |
| 625 | sector_t bblock, unsigned blocksize) |
| 626 | { |
| 627 | struct buffer_head *bh = __find_get_block(bdev, bblock + 1, blocksize); |
| 628 | if (bh) { |
| 629 | if (buffer_dirty(bh)) |
| 630 | ll_rw_block(WRITE, 1, &bh); |
| 631 | put_bh(bh); |
| 632 | } |
| 633 | } |
| 634 | |
| 635 | void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode) |
| 636 | { |
| 637 | struct address_space *mapping = inode->i_mapping; |
| 638 | struct address_space *buffer_mapping = bh->b_page->mapping; |
| 639 | |
| 640 | mark_buffer_dirty(bh); |
| 641 | if (!mapping->assoc_mapping) { |
| 642 | mapping->assoc_mapping = buffer_mapping; |
| 643 | } else { |
Eric Sesterhenn | e827f92 | 2006-03-26 18:24:46 +0200 | [diff] [blame] | 644 | BUG_ON(mapping->assoc_mapping != buffer_mapping); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 645 | } |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 646 | if (!bh->b_assoc_map) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 647 | spin_lock(&buffer_mapping->private_lock); |
| 648 | list_move_tail(&bh->b_assoc_buffers, |
| 649 | &mapping->private_list); |
Jan Kara | 58ff407 | 2006-10-17 00:10:19 -0700 | [diff] [blame] | 650 | bh->b_assoc_map = mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 651 | spin_unlock(&buffer_mapping->private_lock); |
| 652 | } |
| 653 | } |
| 654 | EXPORT_SYMBOL(mark_buffer_dirty_inode); |
| 655 | |
| 656 | /* |
Nick Piggin | 787d221 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 657 | * Mark the page dirty, and set it dirty in the radix tree, and mark the inode |
| 658 | * dirty. |
| 659 | * |
| 660 | * If warn is true, then emit a warning if the page is not uptodate and has |
| 661 | * not been truncated. |
| 662 | */ |
Linus Torvalds | a8e7d49 | 2009-03-19 11:32:05 -0700 | [diff] [blame] | 663 | static void __set_page_dirty(struct page *page, |
Nick Piggin | 787d221 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 664 | struct address_space *mapping, int warn) |
| 665 | { |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 666 | spin_lock_irq(&mapping->tree_lock); |
Nick Piggin | 787d221 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 667 | if (page->mapping) { /* Race with truncate? */ |
| 668 | WARN_ON_ONCE(warn && !PageUptodate(page)); |
Edward Shishkin | e3a7cca | 2009-03-31 15:19:39 -0700 | [diff] [blame] | 669 | account_page_dirtied(page, mapping); |
Nick Piggin | 787d221 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 670 | radix_tree_tag_set(&mapping->page_tree, |
| 671 | page_index(page), PAGECACHE_TAG_DIRTY); |
| 672 | } |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 673 | spin_unlock_irq(&mapping->tree_lock); |
Nick Piggin | 787d221 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 674 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); |
Nick Piggin | 787d221 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 675 | } |
| 676 | |
| 677 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 678 | * Add a page to the dirty page list. |
| 679 | * |
| 680 | * It is a sad fact of life that this function is called from several places |
| 681 | * deeply under spinlocking. It may not sleep. |
| 682 | * |
| 683 | * If the page has buffers, the uptodate buffers are set dirty, to preserve |
| 684 | * dirty-state coherency between the page and the buffers. It the page does |
| 685 | * not have buffers then when they are later attached they will all be set |
| 686 | * dirty. |
| 687 | * |
| 688 | * The buffers are dirtied before the page is dirtied. There's a small race |
| 689 | * window in which a writepage caller may see the page cleanness but not the |
| 690 | * buffer dirtiness. That's fine. If this code were to set the page dirty |
| 691 | * before the buffers, a concurrent writepage caller could clear the page dirty |
| 692 | * bit, see a bunch of clean buffers and we'd end up with dirty buffers/clean |
| 693 | * page on the dirty page list. |
| 694 | * |
| 695 | * We use private_lock to lock against try_to_free_buffers while using the |
| 696 | * page's buffer list. Also use this to protect against clean buffers being |
| 697 | * added to the page after it was set dirty. |
| 698 | * |
| 699 | * FIXME: may need to call ->reservepage here as well. That's rather up to the |
| 700 | * address_space though. |
| 701 | */ |
| 702 | int __set_page_dirty_buffers(struct page *page) |
| 703 | { |
Linus Torvalds | a8e7d49 | 2009-03-19 11:32:05 -0700 | [diff] [blame] | 704 | int newly_dirty; |
Nick Piggin | 787d221 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 705 | struct address_space *mapping = page_mapping(page); |
Nick Piggin | ebf7a22 | 2006-10-10 04:36:54 +0200 | [diff] [blame] | 706 | |
| 707 | if (unlikely(!mapping)) |
| 708 | return !TestSetPageDirty(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 709 | |
| 710 | spin_lock(&mapping->private_lock); |
| 711 | if (page_has_buffers(page)) { |
| 712 | struct buffer_head *head = page_buffers(page); |
| 713 | struct buffer_head *bh = head; |
| 714 | |
| 715 | do { |
| 716 | set_buffer_dirty(bh); |
| 717 | bh = bh->b_this_page; |
| 718 | } while (bh != head); |
| 719 | } |
Linus Torvalds | a8e7d49 | 2009-03-19 11:32:05 -0700 | [diff] [blame] | 720 | newly_dirty = !TestSetPageDirty(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 721 | spin_unlock(&mapping->private_lock); |
| 722 | |
Linus Torvalds | a8e7d49 | 2009-03-19 11:32:05 -0700 | [diff] [blame] | 723 | if (newly_dirty) |
| 724 | __set_page_dirty(page, mapping, 1); |
| 725 | return newly_dirty; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 726 | } |
| 727 | EXPORT_SYMBOL(__set_page_dirty_buffers); |
| 728 | |
| 729 | /* |
| 730 | * Write out and wait upon a list of buffers. |
| 731 | * |
| 732 | * We have conflicting pressures: we want to make sure that all |
| 733 | * initially dirty buffers get waited on, but that any subsequently |
| 734 | * dirtied buffers don't. After all, we don't want fsync to last |
| 735 | * forever if somebody is actively writing to the file. |
| 736 | * |
| 737 | * Do this in two main stages: first we copy dirty buffers to a |
| 738 | * temporary inode list, queueing the writes as we go. Then we clean |
| 739 | * up, waiting for those writes to complete. |
| 740 | * |
| 741 | * During this second stage, any subsequent updates to the file may end |
| 742 | * up refiling the buffer on the original inode's dirty list again, so |
| 743 | * there is a chance we will end up with a buffer queued for write but |
| 744 | * not yet completed on that list. So, as a final cleanup we go through |
| 745 | * the osync code to catch these locked, dirty buffers without requeuing |
| 746 | * any newly dirty buffers for write. |
| 747 | */ |
| 748 | static int fsync_buffers_list(spinlock_t *lock, struct list_head *list) |
| 749 | { |
| 750 | struct buffer_head *bh; |
| 751 | struct list_head tmp; |
Jens Axboe | 7eaceac | 2011-03-10 08:52:07 +0100 | [diff] [blame] | 752 | struct address_space *mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 753 | int err = 0, err2; |
Jens Axboe | 4ee2491 | 2011-03-17 10:51:40 +0100 | [diff] [blame] | 754 | struct blk_plug plug; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 755 | |
| 756 | INIT_LIST_HEAD(&tmp); |
Jens Axboe | 4ee2491 | 2011-03-17 10:51:40 +0100 | [diff] [blame] | 757 | blk_start_plug(&plug); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 758 | |
| 759 | spin_lock(lock); |
| 760 | while (!list_empty(list)) { |
| 761 | bh = BH_ENTRY(list->next); |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 762 | mapping = bh->b_assoc_map; |
Jan Kara | 58ff407 | 2006-10-17 00:10:19 -0700 | [diff] [blame] | 763 | __remove_assoc_queue(bh); |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 764 | /* Avoid race with mark_buffer_dirty_inode() which does |
| 765 | * a lockless check and we rely on seeing the dirty bit */ |
| 766 | smp_mb(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 767 | if (buffer_dirty(bh) || buffer_locked(bh)) { |
| 768 | list_add(&bh->b_assoc_buffers, &tmp); |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 769 | bh->b_assoc_map = mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 770 | if (buffer_dirty(bh)) { |
| 771 | get_bh(bh); |
| 772 | spin_unlock(lock); |
| 773 | /* |
| 774 | * Ensure any pending I/O completes so that |
Christoph Hellwig | 9cb569d | 2010-08-11 17:06:24 +0200 | [diff] [blame] | 775 | * write_dirty_buffer() actually writes the |
| 776 | * current contents - it is a noop if I/O is |
| 777 | * still in flight on potentially older |
| 778 | * contents. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 779 | */ |
Jens Axboe | 721a960 | 2011-03-09 11:56:30 +0100 | [diff] [blame] | 780 | write_dirty_buffer(bh, WRITE_SYNC); |
Jens Axboe | 9cf6b72 | 2009-04-06 14:48:03 +0200 | [diff] [blame] | 781 | |
| 782 | /* |
| 783 | * Kick off IO for the previous mapping. Note |
| 784 | * that we will not run the very last mapping, |
| 785 | * wait_on_buffer() will do that for us |
| 786 | * through sync_buffer(). |
| 787 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 788 | brelse(bh); |
| 789 | spin_lock(lock); |
| 790 | } |
| 791 | } |
| 792 | } |
| 793 | |
Jens Axboe | 4ee2491 | 2011-03-17 10:51:40 +0100 | [diff] [blame] | 794 | spin_unlock(lock); |
| 795 | blk_finish_plug(&plug); |
| 796 | spin_lock(lock); |
| 797 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 798 | while (!list_empty(&tmp)) { |
| 799 | bh = BH_ENTRY(tmp.prev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 800 | get_bh(bh); |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 801 | mapping = bh->b_assoc_map; |
| 802 | __remove_assoc_queue(bh); |
| 803 | /* Avoid race with mark_buffer_dirty_inode() which does |
| 804 | * a lockless check and we rely on seeing the dirty bit */ |
| 805 | smp_mb(); |
| 806 | if (buffer_dirty(bh)) { |
| 807 | list_add(&bh->b_assoc_buffers, |
Jan Kara | e389229 | 2008-03-04 14:28:33 -0800 | [diff] [blame] | 808 | &mapping->private_list); |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 809 | bh->b_assoc_map = mapping; |
| 810 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 811 | spin_unlock(lock); |
| 812 | wait_on_buffer(bh); |
| 813 | if (!buffer_uptodate(bh)) |
| 814 | err = -EIO; |
| 815 | brelse(bh); |
| 816 | spin_lock(lock); |
| 817 | } |
| 818 | |
| 819 | spin_unlock(lock); |
| 820 | err2 = osync_buffers_list(lock, list); |
| 821 | if (err) |
| 822 | return err; |
| 823 | else |
| 824 | return err2; |
| 825 | } |
| 826 | |
| 827 | /* |
| 828 | * Invalidate any and all dirty buffers on a given inode. We are |
| 829 | * probably unmounting the fs, but that doesn't mean we have already |
| 830 | * done a sync(). Just drop the buffers from the inode list. |
| 831 | * |
| 832 | * NOTE: we take the inode's blockdev's mapping's private_lock. Which |
| 833 | * assumes that all the buffers are against the blockdev. Not true |
| 834 | * for reiserfs. |
| 835 | */ |
| 836 | void invalidate_inode_buffers(struct inode *inode) |
| 837 | { |
| 838 | if (inode_has_buffers(inode)) { |
| 839 | struct address_space *mapping = &inode->i_data; |
| 840 | struct list_head *list = &mapping->private_list; |
| 841 | struct address_space *buffer_mapping = mapping->assoc_mapping; |
| 842 | |
| 843 | spin_lock(&buffer_mapping->private_lock); |
| 844 | while (!list_empty(list)) |
| 845 | __remove_assoc_queue(BH_ENTRY(list->next)); |
| 846 | spin_unlock(&buffer_mapping->private_lock); |
| 847 | } |
| 848 | } |
Jan Kara | 52b19ac | 2008-09-23 18:24:08 +0200 | [diff] [blame] | 849 | EXPORT_SYMBOL(invalidate_inode_buffers); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 850 | |
| 851 | /* |
| 852 | * Remove any clean buffers from the inode's buffer list. This is called |
| 853 | * when we're trying to free the inode itself. Those buffers can pin it. |
| 854 | * |
| 855 | * Returns true if all buffers were removed. |
| 856 | */ |
| 857 | int remove_inode_buffers(struct inode *inode) |
| 858 | { |
| 859 | int ret = 1; |
| 860 | |
| 861 | if (inode_has_buffers(inode)) { |
| 862 | struct address_space *mapping = &inode->i_data; |
| 863 | struct list_head *list = &mapping->private_list; |
| 864 | struct address_space *buffer_mapping = mapping->assoc_mapping; |
| 865 | |
| 866 | spin_lock(&buffer_mapping->private_lock); |
| 867 | while (!list_empty(list)) { |
| 868 | struct buffer_head *bh = BH_ENTRY(list->next); |
| 869 | if (buffer_dirty(bh)) { |
| 870 | ret = 0; |
| 871 | break; |
| 872 | } |
| 873 | __remove_assoc_queue(bh); |
| 874 | } |
| 875 | spin_unlock(&buffer_mapping->private_lock); |
| 876 | } |
| 877 | return ret; |
| 878 | } |
| 879 | |
| 880 | /* |
| 881 | * Create the appropriate buffers when given a page for data area and |
| 882 | * the size of each buffer.. Use the bh->b_this_page linked list to |
| 883 | * follow the buffers created. Return NULL if unable to create more |
| 884 | * buffers. |
| 885 | * |
| 886 | * The retry flag is used to differentiate async IO (paging, swapping) |
| 887 | * which may not fail from ordinary buffer allocations. |
| 888 | */ |
| 889 | struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, |
| 890 | int retry) |
| 891 | { |
| 892 | struct buffer_head *bh, *head; |
| 893 | long offset; |
| 894 | |
| 895 | try_again: |
| 896 | head = NULL; |
| 897 | offset = PAGE_SIZE; |
| 898 | while ((offset -= size) >= 0) { |
| 899 | bh = alloc_buffer_head(GFP_NOFS); |
| 900 | if (!bh) |
| 901 | goto no_grow; |
| 902 | |
| 903 | bh->b_bdev = NULL; |
| 904 | bh->b_this_page = head; |
| 905 | bh->b_blocknr = -1; |
| 906 | head = bh; |
| 907 | |
| 908 | bh->b_state = 0; |
| 909 | atomic_set(&bh->b_count, 0); |
| 910 | bh->b_size = size; |
| 911 | |
| 912 | /* Link the buffer to its page */ |
| 913 | set_bh_page(bh, page, offset); |
| 914 | |
Nathan Scott | 01ffe33 | 2006-01-17 09:02:07 +1100 | [diff] [blame] | 915 | init_buffer(bh, NULL, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 916 | } |
| 917 | return head; |
| 918 | /* |
| 919 | * In case anything failed, we just free everything we got. |
| 920 | */ |
| 921 | no_grow: |
| 922 | if (head) { |
| 923 | do { |
| 924 | bh = head; |
| 925 | head = head->b_this_page; |
| 926 | free_buffer_head(bh); |
| 927 | } while (head); |
| 928 | } |
| 929 | |
| 930 | /* |
| 931 | * Return failure for non-async IO requests. Async IO requests |
| 932 | * are not allowed to fail, so we have to wait until buffer heads |
| 933 | * become available. But we don't want tasks sleeping with |
| 934 | * partially complete buffers, so all were released above. |
| 935 | */ |
| 936 | if (!retry) |
| 937 | return NULL; |
| 938 | |
| 939 | /* We're _really_ low on memory. Now we just |
| 940 | * wait for old buffer heads to become free due to |
| 941 | * finishing IO. Since this is an async request and |
| 942 | * the reserve list is empty, we're sure there are |
| 943 | * async buffer heads in use. |
| 944 | */ |
| 945 | free_more_memory(); |
| 946 | goto try_again; |
| 947 | } |
| 948 | EXPORT_SYMBOL_GPL(alloc_page_buffers); |
| 949 | |
| 950 | static inline void |
| 951 | link_dev_buffers(struct page *page, struct buffer_head *head) |
| 952 | { |
| 953 | struct buffer_head *bh, *tail; |
| 954 | |
| 955 | bh = head; |
| 956 | do { |
| 957 | tail = bh; |
| 958 | bh = bh->b_this_page; |
| 959 | } while (bh); |
| 960 | tail->b_this_page = head; |
| 961 | attach_page_buffers(page, head); |
| 962 | } |
| 963 | |
| 964 | /* |
| 965 | * Initialise the state of a blockdev page's buffers. |
| 966 | */ |
| 967 | static void |
| 968 | init_page_buffers(struct page *page, struct block_device *bdev, |
| 969 | sector_t block, int size) |
| 970 | { |
| 971 | struct buffer_head *head = page_buffers(page); |
| 972 | struct buffer_head *bh = head; |
| 973 | int uptodate = PageUptodate(page); |
| 974 | |
| 975 | do { |
| 976 | if (!buffer_mapped(bh)) { |
| 977 | init_buffer(bh, NULL, NULL); |
| 978 | bh->b_bdev = bdev; |
| 979 | bh->b_blocknr = block; |
| 980 | if (uptodate) |
| 981 | set_buffer_uptodate(bh); |
| 982 | set_buffer_mapped(bh); |
| 983 | } |
| 984 | block++; |
| 985 | bh = bh->b_this_page; |
| 986 | } while (bh != head); |
| 987 | } |
| 988 | |
| 989 | /* |
| 990 | * Create the page-cache page that contains the requested block. |
| 991 | * |
| 992 | * This is user purely for blockdev mappings. |
| 993 | */ |
| 994 | static struct page * |
| 995 | grow_dev_page(struct block_device *bdev, sector_t block, |
| 996 | pgoff_t index, int size) |
| 997 | { |
| 998 | struct inode *inode = bdev->bd_inode; |
| 999 | struct page *page; |
| 1000 | struct buffer_head *bh; |
| 1001 | |
Christoph Lameter | ea12589 | 2007-05-16 22:11:21 -0700 | [diff] [blame] | 1002 | page = find_or_create_page(inode->i_mapping, index, |
Mel Gorman | 769848c | 2007-07-17 04:03:05 -0700 | [diff] [blame] | 1003 | (mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS)|__GFP_MOVABLE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1004 | if (!page) |
| 1005 | return NULL; |
| 1006 | |
Eric Sesterhenn | e827f92 | 2006-03-26 18:24:46 +0200 | [diff] [blame] | 1007 | BUG_ON(!PageLocked(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1008 | |
| 1009 | if (page_has_buffers(page)) { |
| 1010 | bh = page_buffers(page); |
| 1011 | if (bh->b_size == size) { |
| 1012 | init_page_buffers(page, bdev, block, size); |
| 1013 | return page; |
| 1014 | } |
| 1015 | if (!try_to_free_buffers(page)) |
| 1016 | goto failed; |
| 1017 | } |
| 1018 | |
| 1019 | /* |
| 1020 | * Allocate some buffers for this page |
| 1021 | */ |
| 1022 | bh = alloc_page_buffers(page, size, 0); |
| 1023 | if (!bh) |
| 1024 | goto failed; |
| 1025 | |
| 1026 | /* |
| 1027 | * Link the page to the buffers and initialise them. Take the |
| 1028 | * lock to be atomic wrt __find_get_block(), which does not |
| 1029 | * run under the page lock. |
| 1030 | */ |
| 1031 | spin_lock(&inode->i_mapping->private_lock); |
| 1032 | link_dev_buffers(page, bh); |
| 1033 | init_page_buffers(page, bdev, block, size); |
| 1034 | spin_unlock(&inode->i_mapping->private_lock); |
| 1035 | return page; |
| 1036 | |
| 1037 | failed: |
| 1038 | BUG(); |
| 1039 | unlock_page(page); |
| 1040 | page_cache_release(page); |
| 1041 | return NULL; |
| 1042 | } |
| 1043 | |
| 1044 | /* |
| 1045 | * Create buffers for the specified block device block's page. If |
| 1046 | * that page was dirty, the buffers are set dirty also. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1047 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 1048 | static int |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1049 | grow_buffers(struct block_device *bdev, sector_t block, int size) |
| 1050 | { |
| 1051 | struct page *page; |
| 1052 | pgoff_t index; |
| 1053 | int sizebits; |
| 1054 | |
| 1055 | sizebits = -1; |
| 1056 | do { |
| 1057 | sizebits++; |
| 1058 | } while ((size << sizebits) < PAGE_SIZE); |
| 1059 | |
| 1060 | index = block >> sizebits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1061 | |
Andrew Morton | e565793 | 2006-10-11 01:21:46 -0700 | [diff] [blame] | 1062 | /* |
| 1063 | * Check for a block which wants to lie outside our maximum possible |
| 1064 | * pagecache index. (this comparison is done using sector_t types). |
| 1065 | */ |
| 1066 | if (unlikely(index != block >> sizebits)) { |
| 1067 | char b[BDEVNAME_SIZE]; |
| 1068 | |
| 1069 | printk(KERN_ERR "%s: requested out-of-range block %llu for " |
| 1070 | "device %s\n", |
Harvey Harrison | 8e24eea | 2008-04-30 00:55:09 -0700 | [diff] [blame] | 1071 | __func__, (unsigned long long)block, |
Andrew Morton | e565793 | 2006-10-11 01:21:46 -0700 | [diff] [blame] | 1072 | bdevname(bdev, b)); |
| 1073 | return -EIO; |
| 1074 | } |
| 1075 | block = index << sizebits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1076 | /* Create a page with the proper size buffers.. */ |
| 1077 | page = grow_dev_page(bdev, block, index, size); |
| 1078 | if (!page) |
| 1079 | return 0; |
| 1080 | unlock_page(page); |
| 1081 | page_cache_release(page); |
| 1082 | return 1; |
| 1083 | } |
| 1084 | |
Adrian Bunk | 75c96f8 | 2005-05-05 16:16:09 -0700 | [diff] [blame] | 1085 | static struct buffer_head * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1086 | __getblk_slow(struct block_device *bdev, sector_t block, int size) |
| 1087 | { |
| 1088 | /* Size must be multiple of hard sectorsize */ |
Martin K. Petersen | e1defc4 | 2009-05-22 17:17:49 -0400 | [diff] [blame] | 1089 | if (unlikely(size & (bdev_logical_block_size(bdev)-1) || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1090 | (size < 512 || size > PAGE_SIZE))) { |
| 1091 | printk(KERN_ERR "getblk(): invalid block size %d requested\n", |
| 1092 | size); |
Martin K. Petersen | e1defc4 | 2009-05-22 17:17:49 -0400 | [diff] [blame] | 1093 | printk(KERN_ERR "logical block size: %d\n", |
| 1094 | bdev_logical_block_size(bdev)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1095 | |
| 1096 | dump_stack(); |
| 1097 | return NULL; |
| 1098 | } |
| 1099 | |
| 1100 | for (;;) { |
| 1101 | struct buffer_head * bh; |
Andrew Morton | e565793 | 2006-10-11 01:21:46 -0700 | [diff] [blame] | 1102 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1103 | |
| 1104 | bh = __find_get_block(bdev, block, size); |
| 1105 | if (bh) |
| 1106 | return bh; |
| 1107 | |
Andrew Morton | e565793 | 2006-10-11 01:21:46 -0700 | [diff] [blame] | 1108 | ret = grow_buffers(bdev, block, size); |
| 1109 | if (ret < 0) |
| 1110 | return NULL; |
| 1111 | if (ret == 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1112 | free_more_memory(); |
| 1113 | } |
| 1114 | } |
| 1115 | |
| 1116 | /* |
| 1117 | * The relationship between dirty buffers and dirty pages: |
| 1118 | * |
| 1119 | * Whenever a page has any dirty buffers, the page's dirty bit is set, and |
| 1120 | * the page is tagged dirty in its radix tree. |
| 1121 | * |
| 1122 | * At all times, the dirtiness of the buffers represents the dirtiness of |
| 1123 | * subsections of the page. If the page has buffers, the page dirty bit is |
| 1124 | * merely a hint about the true dirty state. |
| 1125 | * |
| 1126 | * When a page is set dirty in its entirety, all its buffers are marked dirty |
| 1127 | * (if the page has buffers). |
| 1128 | * |
| 1129 | * When a buffer is marked dirty, its page is dirtied, but the page's other |
| 1130 | * buffers are not. |
| 1131 | * |
| 1132 | * Also. When blockdev buffers are explicitly read with bread(), they |
| 1133 | * individually become uptodate. But their backing page remains not |
| 1134 | * uptodate - even if all of its buffers are uptodate. A subsequent |
| 1135 | * block_read_full_page() against that page will discover all the uptodate |
| 1136 | * buffers, will set the page uptodate and will perform no I/O. |
| 1137 | */ |
| 1138 | |
| 1139 | /** |
| 1140 | * mark_buffer_dirty - mark a buffer_head as needing writeout |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 1141 | * @bh: the buffer_head to mark dirty |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1142 | * |
| 1143 | * mark_buffer_dirty() will set the dirty bit against the buffer, then set its |
| 1144 | * backing page dirty, then tag the page as dirty in its address_space's radix |
| 1145 | * tree and then attach the address_space's inode to its superblock's dirty |
| 1146 | * inode list. |
| 1147 | * |
| 1148 | * mark_buffer_dirty() is atomic. It takes bh->b_page->mapping->private_lock, |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 1149 | * mapping->tree_lock and mapping->host->i_lock. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1150 | */ |
Harvey Harrison | fc9b52c | 2008-02-08 04:19:52 -0800 | [diff] [blame] | 1151 | void mark_buffer_dirty(struct buffer_head *bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1152 | { |
Nick Piggin | 787d221 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 1153 | WARN_ON_ONCE(!buffer_uptodate(bh)); |
Linus Torvalds | 1be62dc | 2008-04-04 14:38:17 -0700 | [diff] [blame] | 1154 | |
| 1155 | /* |
| 1156 | * Very *carefully* optimize the it-is-already-dirty case. |
| 1157 | * |
| 1158 | * Don't let the final "is it dirty" escape to before we |
| 1159 | * perhaps modified the buffer. |
| 1160 | */ |
| 1161 | if (buffer_dirty(bh)) { |
| 1162 | smp_mb(); |
| 1163 | if (buffer_dirty(bh)) |
| 1164 | return; |
| 1165 | } |
| 1166 | |
Linus Torvalds | a8e7d49 | 2009-03-19 11:32:05 -0700 | [diff] [blame] | 1167 | if (!test_set_buffer_dirty(bh)) { |
| 1168 | struct page *page = bh->b_page; |
Linus Torvalds | 8e9d78e | 2009-08-21 17:40:08 -0700 | [diff] [blame] | 1169 | if (!TestSetPageDirty(page)) { |
| 1170 | struct address_space *mapping = page_mapping(page); |
| 1171 | if (mapping) |
| 1172 | __set_page_dirty(page, mapping, 0); |
| 1173 | } |
Linus Torvalds | a8e7d49 | 2009-03-19 11:32:05 -0700 | [diff] [blame] | 1174 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1175 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 1176 | EXPORT_SYMBOL(mark_buffer_dirty); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1177 | |
| 1178 | /* |
| 1179 | * Decrement a buffer_head's reference count. If all buffers against a page |
| 1180 | * have zero reference count, are clean and unlocked, and if the page is clean |
| 1181 | * and unlocked then try_to_free_buffers() may strip the buffers from the page |
| 1182 | * in preparation for freeing it (sometimes, rarely, buffers are removed from |
| 1183 | * a page but it ends up not being freed, and buffers may later be reattached). |
| 1184 | */ |
| 1185 | void __brelse(struct buffer_head * buf) |
| 1186 | { |
| 1187 | if (atomic_read(&buf->b_count)) { |
| 1188 | put_bh(buf); |
| 1189 | return; |
| 1190 | } |
Arjan van de Ven | 5c752ad | 2008-07-25 19:45:40 -0700 | [diff] [blame] | 1191 | WARN(1, KERN_ERR "VFS: brelse: Trying to free free buffer\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1192 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 1193 | EXPORT_SYMBOL(__brelse); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1194 | |
| 1195 | /* |
| 1196 | * bforget() is like brelse(), except it discards any |
| 1197 | * potentially dirty data. |
| 1198 | */ |
| 1199 | void __bforget(struct buffer_head *bh) |
| 1200 | { |
| 1201 | clear_buffer_dirty(bh); |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 1202 | if (bh->b_assoc_map) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1203 | struct address_space *buffer_mapping = bh->b_page->mapping; |
| 1204 | |
| 1205 | spin_lock(&buffer_mapping->private_lock); |
| 1206 | list_del_init(&bh->b_assoc_buffers); |
Jan Kara | 58ff407 | 2006-10-17 00:10:19 -0700 | [diff] [blame] | 1207 | bh->b_assoc_map = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1208 | spin_unlock(&buffer_mapping->private_lock); |
| 1209 | } |
| 1210 | __brelse(bh); |
| 1211 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 1212 | EXPORT_SYMBOL(__bforget); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1213 | |
| 1214 | static struct buffer_head *__bread_slow(struct buffer_head *bh) |
| 1215 | { |
| 1216 | lock_buffer(bh); |
| 1217 | if (buffer_uptodate(bh)) { |
| 1218 | unlock_buffer(bh); |
| 1219 | return bh; |
| 1220 | } else { |
| 1221 | get_bh(bh); |
| 1222 | bh->b_end_io = end_buffer_read_sync; |
| 1223 | submit_bh(READ, bh); |
| 1224 | wait_on_buffer(bh); |
| 1225 | if (buffer_uptodate(bh)) |
| 1226 | return bh; |
| 1227 | } |
| 1228 | brelse(bh); |
| 1229 | return NULL; |
| 1230 | } |
| 1231 | |
| 1232 | /* |
| 1233 | * Per-cpu buffer LRU implementation. To reduce the cost of __find_get_block(). |
| 1234 | * The bhs[] array is sorted - newest buffer is at bhs[0]. Buffers have their |
| 1235 | * refcount elevated by one when they're in an LRU. A buffer can only appear |
| 1236 | * once in a particular CPU's LRU. A single buffer can be present in multiple |
| 1237 | * CPU's LRUs at the same time. |
| 1238 | * |
| 1239 | * This is a transparent caching front-end to sb_bread(), sb_getblk() and |
| 1240 | * sb_find_get_block(). |
| 1241 | * |
| 1242 | * The LRUs themselves only need locking against invalidate_bh_lrus. We use |
| 1243 | * a local interrupt disable for that. |
| 1244 | */ |
| 1245 | |
| 1246 | #define BH_LRU_SIZE 8 |
| 1247 | |
| 1248 | struct bh_lru { |
| 1249 | struct buffer_head *bhs[BH_LRU_SIZE]; |
| 1250 | }; |
| 1251 | |
| 1252 | static DEFINE_PER_CPU(struct bh_lru, bh_lrus) = {{ NULL }}; |
| 1253 | |
| 1254 | #ifdef CONFIG_SMP |
| 1255 | #define bh_lru_lock() local_irq_disable() |
| 1256 | #define bh_lru_unlock() local_irq_enable() |
| 1257 | #else |
| 1258 | #define bh_lru_lock() preempt_disable() |
| 1259 | #define bh_lru_unlock() preempt_enable() |
| 1260 | #endif |
| 1261 | |
| 1262 | static inline void check_irqs_on(void) |
| 1263 | { |
| 1264 | #ifdef irqs_disabled |
| 1265 | BUG_ON(irqs_disabled()); |
| 1266 | #endif |
| 1267 | } |
| 1268 | |
| 1269 | /* |
| 1270 | * The LRU management algorithm is dopey-but-simple. Sorry. |
| 1271 | */ |
| 1272 | static void bh_lru_install(struct buffer_head *bh) |
| 1273 | { |
| 1274 | struct buffer_head *evictee = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1275 | |
| 1276 | check_irqs_on(); |
| 1277 | bh_lru_lock(); |
Christoph Lameter | c7b9251 | 2010-12-06 11:16:28 -0600 | [diff] [blame] | 1278 | if (__this_cpu_read(bh_lrus.bhs[0]) != bh) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1279 | struct buffer_head *bhs[BH_LRU_SIZE]; |
| 1280 | int in; |
| 1281 | int out = 0; |
| 1282 | |
| 1283 | get_bh(bh); |
| 1284 | bhs[out++] = bh; |
| 1285 | for (in = 0; in < BH_LRU_SIZE; in++) { |
Christoph Lameter | c7b9251 | 2010-12-06 11:16:28 -0600 | [diff] [blame] | 1286 | struct buffer_head *bh2 = |
| 1287 | __this_cpu_read(bh_lrus.bhs[in]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1288 | |
| 1289 | if (bh2 == bh) { |
| 1290 | __brelse(bh2); |
| 1291 | } else { |
| 1292 | if (out >= BH_LRU_SIZE) { |
| 1293 | BUG_ON(evictee != NULL); |
| 1294 | evictee = bh2; |
| 1295 | } else { |
| 1296 | bhs[out++] = bh2; |
| 1297 | } |
| 1298 | } |
| 1299 | } |
| 1300 | while (out < BH_LRU_SIZE) |
| 1301 | bhs[out++] = NULL; |
Christoph Lameter | c7b9251 | 2010-12-06 11:16:28 -0600 | [diff] [blame] | 1302 | memcpy(__this_cpu_ptr(&bh_lrus.bhs), bhs, sizeof(bhs)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1303 | } |
| 1304 | bh_lru_unlock(); |
| 1305 | |
| 1306 | if (evictee) |
| 1307 | __brelse(evictee); |
| 1308 | } |
| 1309 | |
| 1310 | /* |
| 1311 | * Look up the bh in this cpu's LRU. If it's there, move it to the head. |
| 1312 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 1313 | static struct buffer_head * |
Tomasz Kvarsin | 3991d3b | 2007-02-12 00:52:14 -0800 | [diff] [blame] | 1314 | lookup_bh_lru(struct block_device *bdev, sector_t block, unsigned size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1315 | { |
| 1316 | struct buffer_head *ret = NULL; |
Tomasz Kvarsin | 3991d3b | 2007-02-12 00:52:14 -0800 | [diff] [blame] | 1317 | unsigned int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1318 | |
| 1319 | check_irqs_on(); |
| 1320 | bh_lru_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1321 | for (i = 0; i < BH_LRU_SIZE; i++) { |
Christoph Lameter | c7b9251 | 2010-12-06 11:16:28 -0600 | [diff] [blame] | 1322 | struct buffer_head *bh = __this_cpu_read(bh_lrus.bhs[i]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1323 | |
| 1324 | if (bh && bh->b_bdev == bdev && |
| 1325 | bh->b_blocknr == block && bh->b_size == size) { |
| 1326 | if (i) { |
| 1327 | while (i) { |
Christoph Lameter | c7b9251 | 2010-12-06 11:16:28 -0600 | [diff] [blame] | 1328 | __this_cpu_write(bh_lrus.bhs[i], |
| 1329 | __this_cpu_read(bh_lrus.bhs[i - 1])); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1330 | i--; |
| 1331 | } |
Christoph Lameter | c7b9251 | 2010-12-06 11:16:28 -0600 | [diff] [blame] | 1332 | __this_cpu_write(bh_lrus.bhs[0], bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1333 | } |
| 1334 | get_bh(bh); |
| 1335 | ret = bh; |
| 1336 | break; |
| 1337 | } |
| 1338 | } |
| 1339 | bh_lru_unlock(); |
| 1340 | return ret; |
| 1341 | } |
| 1342 | |
| 1343 | /* |
| 1344 | * Perform a pagecache lookup for the matching buffer. If it's there, refresh |
| 1345 | * it in the LRU and mark it as accessed. If it is not present then return |
| 1346 | * NULL |
| 1347 | */ |
| 1348 | struct buffer_head * |
Tomasz Kvarsin | 3991d3b | 2007-02-12 00:52:14 -0800 | [diff] [blame] | 1349 | __find_get_block(struct block_device *bdev, sector_t block, unsigned size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1350 | { |
| 1351 | struct buffer_head *bh = lookup_bh_lru(bdev, block, size); |
| 1352 | |
| 1353 | if (bh == NULL) { |
Coywolf Qi Hunt | 385fd4c | 2005-11-07 00:59:39 -0800 | [diff] [blame] | 1354 | bh = __find_get_block_slow(bdev, block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1355 | if (bh) |
| 1356 | bh_lru_install(bh); |
| 1357 | } |
| 1358 | if (bh) |
| 1359 | touch_buffer(bh); |
| 1360 | return bh; |
| 1361 | } |
| 1362 | EXPORT_SYMBOL(__find_get_block); |
| 1363 | |
| 1364 | /* |
| 1365 | * __getblk will locate (and, if necessary, create) the buffer_head |
| 1366 | * which corresponds to the passed block_device, block and size. The |
| 1367 | * returned buffer has its reference count incremented. |
| 1368 | * |
| 1369 | * __getblk() cannot fail - it just keeps trying. If you pass it an |
| 1370 | * illegal block number, __getblk() will happily return a buffer_head |
| 1371 | * which represents the non-existent block. Very weird. |
| 1372 | * |
| 1373 | * __getblk() will lock up the machine if grow_dev_page's try_to_free_buffers() |
| 1374 | * attempt is failing. FIXME, perhaps? |
| 1375 | */ |
| 1376 | struct buffer_head * |
Tomasz Kvarsin | 3991d3b | 2007-02-12 00:52:14 -0800 | [diff] [blame] | 1377 | __getblk(struct block_device *bdev, sector_t block, unsigned size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1378 | { |
| 1379 | struct buffer_head *bh = __find_get_block(bdev, block, size); |
| 1380 | |
| 1381 | might_sleep(); |
| 1382 | if (bh == NULL) |
| 1383 | bh = __getblk_slow(bdev, block, size); |
| 1384 | return bh; |
| 1385 | } |
| 1386 | EXPORT_SYMBOL(__getblk); |
| 1387 | |
| 1388 | /* |
| 1389 | * Do async read-ahead on a buffer.. |
| 1390 | */ |
Tomasz Kvarsin | 3991d3b | 2007-02-12 00:52:14 -0800 | [diff] [blame] | 1391 | void __breadahead(struct block_device *bdev, sector_t block, unsigned size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1392 | { |
| 1393 | struct buffer_head *bh = __getblk(bdev, block, size); |
Andrew Morton | a3e713b | 2005-10-30 15:03:15 -0800 | [diff] [blame] | 1394 | if (likely(bh)) { |
| 1395 | ll_rw_block(READA, 1, &bh); |
| 1396 | brelse(bh); |
| 1397 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1398 | } |
| 1399 | EXPORT_SYMBOL(__breadahead); |
| 1400 | |
| 1401 | /** |
| 1402 | * __bread() - reads a specified block and returns the bh |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 1403 | * @bdev: the block_device to read from |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1404 | * @block: number of block |
| 1405 | * @size: size (in bytes) to read |
| 1406 | * |
| 1407 | * Reads a specified block, and returns buffer head that contains it. |
| 1408 | * It returns NULL if the block was unreadable. |
| 1409 | */ |
| 1410 | struct buffer_head * |
Tomasz Kvarsin | 3991d3b | 2007-02-12 00:52:14 -0800 | [diff] [blame] | 1411 | __bread(struct block_device *bdev, sector_t block, unsigned size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1412 | { |
| 1413 | struct buffer_head *bh = __getblk(bdev, block, size); |
| 1414 | |
Andrew Morton | a3e713b | 2005-10-30 15:03:15 -0800 | [diff] [blame] | 1415 | if (likely(bh) && !buffer_uptodate(bh)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1416 | bh = __bread_slow(bh); |
| 1417 | return bh; |
| 1418 | } |
| 1419 | EXPORT_SYMBOL(__bread); |
| 1420 | |
| 1421 | /* |
| 1422 | * invalidate_bh_lrus() is called rarely - but not only at unmount. |
| 1423 | * This doesn't race because it runs in each cpu either in irq |
| 1424 | * or with preempt disabled. |
| 1425 | */ |
| 1426 | static void invalidate_bh_lru(void *arg) |
| 1427 | { |
| 1428 | struct bh_lru *b = &get_cpu_var(bh_lrus); |
| 1429 | int i; |
| 1430 | |
| 1431 | for (i = 0; i < BH_LRU_SIZE; i++) { |
| 1432 | brelse(b->bhs[i]); |
| 1433 | b->bhs[i] = NULL; |
| 1434 | } |
| 1435 | put_cpu_var(bh_lrus); |
| 1436 | } |
| 1437 | |
Peter Zijlstra | f9a1439 | 2007-05-06 14:49:55 -0700 | [diff] [blame] | 1438 | void invalidate_bh_lrus(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1439 | { |
Jens Axboe | 15c8b6c | 2008-05-09 09:39:44 +0200 | [diff] [blame] | 1440 | on_each_cpu(invalidate_bh_lru, NULL, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1441 | } |
Nick Piggin | 9db5579 | 2008-02-08 04:19:49 -0800 | [diff] [blame] | 1442 | EXPORT_SYMBOL_GPL(invalidate_bh_lrus); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1443 | |
| 1444 | void set_bh_page(struct buffer_head *bh, |
| 1445 | struct page *page, unsigned long offset) |
| 1446 | { |
| 1447 | bh->b_page = page; |
Eric Sesterhenn | e827f92 | 2006-03-26 18:24:46 +0200 | [diff] [blame] | 1448 | BUG_ON(offset >= PAGE_SIZE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1449 | if (PageHighMem(page)) |
| 1450 | /* |
| 1451 | * This catches illegal uses and preserves the offset: |
| 1452 | */ |
| 1453 | bh->b_data = (char *)(0 + offset); |
| 1454 | else |
| 1455 | bh->b_data = page_address(page) + offset; |
| 1456 | } |
| 1457 | EXPORT_SYMBOL(set_bh_page); |
| 1458 | |
| 1459 | /* |
| 1460 | * Called when truncating a buffer on a page completely. |
| 1461 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 1462 | static void discard_buffer(struct buffer_head * bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1463 | { |
| 1464 | lock_buffer(bh); |
| 1465 | clear_buffer_dirty(bh); |
| 1466 | bh->b_bdev = NULL; |
| 1467 | clear_buffer_mapped(bh); |
| 1468 | clear_buffer_req(bh); |
| 1469 | clear_buffer_new(bh); |
| 1470 | clear_buffer_delay(bh); |
David Chinner | 33a266d | 2007-02-12 00:51:41 -0800 | [diff] [blame] | 1471 | clear_buffer_unwritten(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1472 | unlock_buffer(bh); |
| 1473 | } |
| 1474 | |
| 1475 | /** |
Wang Sheng-Hui | 814e1d2 | 2011-09-01 08:22:57 +0800 | [diff] [blame] | 1476 | * block_invalidatepage - invalidate part or all of a buffer-backed page |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1477 | * |
| 1478 | * @page: the page which is affected |
| 1479 | * @offset: the index of the truncation point |
| 1480 | * |
| 1481 | * block_invalidatepage() is called when all or part of the page has become |
Wang Sheng-Hui | 814e1d2 | 2011-09-01 08:22:57 +0800 | [diff] [blame] | 1482 | * invalidated by a truncate operation. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1483 | * |
| 1484 | * block_invalidatepage() does not have to release all buffers, but it must |
| 1485 | * ensure that no dirty buffer is left outside @offset and that no I/O |
| 1486 | * is underway against any of the blocks which are outside the truncation |
| 1487 | * point. Because the caller is about to free (and possibly reuse) those |
| 1488 | * blocks on-disk. |
| 1489 | */ |
NeilBrown | 2ff28e2 | 2006-03-26 01:37:18 -0800 | [diff] [blame] | 1490 | void block_invalidatepage(struct page *page, unsigned long offset) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1491 | { |
| 1492 | struct buffer_head *head, *bh, *next; |
| 1493 | unsigned int curr_off = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1494 | |
| 1495 | BUG_ON(!PageLocked(page)); |
| 1496 | if (!page_has_buffers(page)) |
| 1497 | goto out; |
| 1498 | |
| 1499 | head = page_buffers(page); |
| 1500 | bh = head; |
| 1501 | do { |
| 1502 | unsigned int next_off = curr_off + bh->b_size; |
| 1503 | next = bh->b_this_page; |
| 1504 | |
| 1505 | /* |
| 1506 | * is this block fully invalidated? |
| 1507 | */ |
| 1508 | if (offset <= curr_off) |
| 1509 | discard_buffer(bh); |
| 1510 | curr_off = next_off; |
| 1511 | bh = next; |
| 1512 | } while (bh != head); |
| 1513 | |
| 1514 | /* |
| 1515 | * We release buffers only if the entire page is being invalidated. |
| 1516 | * The get_block cached value has been unconditionally invalidated, |
| 1517 | * so real IO is not possible anymore. |
| 1518 | */ |
| 1519 | if (offset == 0) |
NeilBrown | 2ff28e2 | 2006-03-26 01:37:18 -0800 | [diff] [blame] | 1520 | try_to_release_page(page, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1521 | out: |
NeilBrown | 2ff28e2 | 2006-03-26 01:37:18 -0800 | [diff] [blame] | 1522 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1523 | } |
| 1524 | EXPORT_SYMBOL(block_invalidatepage); |
| 1525 | |
| 1526 | /* |
| 1527 | * We attach and possibly dirty the buffers atomically wrt |
| 1528 | * __set_page_dirty_buffers() via private_lock. try_to_free_buffers |
| 1529 | * is already excluded via the page lock. |
| 1530 | */ |
| 1531 | void create_empty_buffers(struct page *page, |
| 1532 | unsigned long blocksize, unsigned long b_state) |
| 1533 | { |
| 1534 | struct buffer_head *bh, *head, *tail; |
| 1535 | |
| 1536 | head = alloc_page_buffers(page, blocksize, 1); |
| 1537 | bh = head; |
| 1538 | do { |
| 1539 | bh->b_state |= b_state; |
| 1540 | tail = bh; |
| 1541 | bh = bh->b_this_page; |
| 1542 | } while (bh); |
| 1543 | tail->b_this_page = head; |
| 1544 | |
| 1545 | spin_lock(&page->mapping->private_lock); |
| 1546 | if (PageUptodate(page) || PageDirty(page)) { |
| 1547 | bh = head; |
| 1548 | do { |
| 1549 | if (PageDirty(page)) |
| 1550 | set_buffer_dirty(bh); |
| 1551 | if (PageUptodate(page)) |
| 1552 | set_buffer_uptodate(bh); |
| 1553 | bh = bh->b_this_page; |
| 1554 | } while (bh != head); |
| 1555 | } |
| 1556 | attach_page_buffers(page, head); |
| 1557 | spin_unlock(&page->mapping->private_lock); |
| 1558 | } |
| 1559 | EXPORT_SYMBOL(create_empty_buffers); |
| 1560 | |
| 1561 | /* |
| 1562 | * We are taking a block for data and we don't want any output from any |
| 1563 | * buffer-cache aliases starting from return from that function and |
| 1564 | * until the moment when something will explicitly mark the buffer |
| 1565 | * dirty (hopefully that will not happen until we will free that block ;-) |
| 1566 | * We don't even need to mark it not-uptodate - nobody can expect |
| 1567 | * anything from a newly allocated buffer anyway. We used to used |
| 1568 | * unmap_buffer() for such invalidation, but that was wrong. We definitely |
| 1569 | * don't want to mark the alias unmapped, for example - it would confuse |
| 1570 | * anyone who might pick it with bread() afterwards... |
| 1571 | * |
| 1572 | * Also.. Note that bforget() doesn't lock the buffer. So there can |
| 1573 | * be writeout I/O going on against recently-freed buffers. We don't |
| 1574 | * wait on that I/O in bforget() - it's more efficient to wait on the I/O |
| 1575 | * only if we really need to. That happens here. |
| 1576 | */ |
| 1577 | void unmap_underlying_metadata(struct block_device *bdev, sector_t block) |
| 1578 | { |
| 1579 | struct buffer_head *old_bh; |
| 1580 | |
| 1581 | might_sleep(); |
| 1582 | |
Coywolf Qi Hunt | 385fd4c | 2005-11-07 00:59:39 -0800 | [diff] [blame] | 1583 | old_bh = __find_get_block_slow(bdev, block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1584 | if (old_bh) { |
| 1585 | clear_buffer_dirty(old_bh); |
| 1586 | wait_on_buffer(old_bh); |
| 1587 | clear_buffer_req(old_bh); |
| 1588 | __brelse(old_bh); |
| 1589 | } |
| 1590 | } |
| 1591 | EXPORT_SYMBOL(unmap_underlying_metadata); |
| 1592 | |
| 1593 | /* |
| 1594 | * NOTE! All mapped/uptodate combinations are valid: |
| 1595 | * |
| 1596 | * Mapped Uptodate Meaning |
| 1597 | * |
| 1598 | * No No "unknown" - must do get_block() |
| 1599 | * No Yes "hole" - zero-filled |
| 1600 | * Yes No "allocated" - allocated on disk, not read in |
| 1601 | * Yes Yes "valid" - allocated and up-to-date in memory. |
| 1602 | * |
| 1603 | * "Dirty" is valid only with the last case (mapped+uptodate). |
| 1604 | */ |
| 1605 | |
| 1606 | /* |
| 1607 | * While block_write_full_page is writing back the dirty buffers under |
| 1608 | * the page lock, whoever dirtied the buffers may decide to clean them |
| 1609 | * again at any time. We handle that by only looking at the buffer |
| 1610 | * state inside lock_buffer(). |
| 1611 | * |
| 1612 | * If block_write_full_page() is called for regular writeback |
| 1613 | * (wbc->sync_mode == WB_SYNC_NONE) then it will redirty a page which has a |
| 1614 | * locked buffer. This only can happen if someone has written the buffer |
| 1615 | * directly, with submit_bh(). At the address_space level PageWriteback |
| 1616 | * prevents this contention from occurring. |
Theodore Ts'o | 6e34eed | 2009-04-07 18:12:43 -0400 | [diff] [blame] | 1617 | * |
| 1618 | * If block_write_full_page() is called with wbc->sync_mode == |
Jens Axboe | 721a960 | 2011-03-09 11:56:30 +0100 | [diff] [blame] | 1619 | * WB_SYNC_ALL, the writes are posted using WRITE_SYNC; this |
| 1620 | * causes the writes to be flagged as synchronous writes. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1621 | */ |
| 1622 | static int __block_write_full_page(struct inode *inode, struct page *page, |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 1623 | get_block_t *get_block, struct writeback_control *wbc, |
| 1624 | bh_end_io_t *handler) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1625 | { |
| 1626 | int err; |
| 1627 | sector_t block; |
| 1628 | sector_t last_block; |
Andrew Morton | f0fbd5f | 2005-05-05 16:15:48 -0700 | [diff] [blame] | 1629 | struct buffer_head *bh, *head; |
Badari Pulavarty | b0cf232 | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 1630 | const unsigned blocksize = 1 << inode->i_blkbits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1631 | int nr_underway = 0; |
Theodore Ts'o | 6e34eed | 2009-04-07 18:12:43 -0400 | [diff] [blame] | 1632 | int write_op = (wbc->sync_mode == WB_SYNC_ALL ? |
Jens Axboe | 721a960 | 2011-03-09 11:56:30 +0100 | [diff] [blame] | 1633 | WRITE_SYNC : WRITE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1634 | |
| 1635 | BUG_ON(!PageLocked(page)); |
| 1636 | |
| 1637 | last_block = (i_size_read(inode) - 1) >> inode->i_blkbits; |
| 1638 | |
| 1639 | if (!page_has_buffers(page)) { |
Badari Pulavarty | b0cf232 | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 1640 | create_empty_buffers(page, blocksize, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1641 | (1 << BH_Dirty)|(1 << BH_Uptodate)); |
| 1642 | } |
| 1643 | |
| 1644 | /* |
| 1645 | * Be very careful. We have no exclusion from __set_page_dirty_buffers |
| 1646 | * here, and the (potentially unmapped) buffers may become dirty at |
| 1647 | * any time. If a buffer becomes dirty here after we've inspected it |
| 1648 | * then we just miss that fact, and the page stays dirty. |
| 1649 | * |
| 1650 | * Buffers outside i_size may be dirtied by __set_page_dirty_buffers; |
| 1651 | * handle that here by just cleaning them. |
| 1652 | */ |
| 1653 | |
Andrew Morton | 54b21a7 | 2006-01-08 01:03:05 -0800 | [diff] [blame] | 1654 | block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1655 | head = page_buffers(page); |
| 1656 | bh = head; |
| 1657 | |
| 1658 | /* |
| 1659 | * Get all the dirty buffers mapped to disk addresses and |
| 1660 | * handle any aliases from the underlying blockdev's mapping. |
| 1661 | */ |
| 1662 | do { |
| 1663 | if (block > last_block) { |
| 1664 | /* |
| 1665 | * mapped buffers outside i_size will occur, because |
| 1666 | * this page can be outside i_size when there is a |
| 1667 | * truncate in progress. |
| 1668 | */ |
| 1669 | /* |
| 1670 | * The buffer was zeroed by block_write_full_page() |
| 1671 | */ |
| 1672 | clear_buffer_dirty(bh); |
| 1673 | set_buffer_uptodate(bh); |
Alex Tomas | 29a814d | 2008-07-11 19:27:31 -0400 | [diff] [blame] | 1674 | } else if ((!buffer_mapped(bh) || buffer_delay(bh)) && |
| 1675 | buffer_dirty(bh)) { |
Badari Pulavarty | b0cf232 | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 1676 | WARN_ON(bh->b_size != blocksize); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1677 | err = get_block(inode, block, bh, 1); |
| 1678 | if (err) |
| 1679 | goto recover; |
Alex Tomas | 29a814d | 2008-07-11 19:27:31 -0400 | [diff] [blame] | 1680 | clear_buffer_delay(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1681 | if (buffer_new(bh)) { |
| 1682 | /* blockdev mappings never come here */ |
| 1683 | clear_buffer_new(bh); |
| 1684 | unmap_underlying_metadata(bh->b_bdev, |
| 1685 | bh->b_blocknr); |
| 1686 | } |
| 1687 | } |
| 1688 | bh = bh->b_this_page; |
| 1689 | block++; |
| 1690 | } while (bh != head); |
| 1691 | |
| 1692 | do { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1693 | if (!buffer_mapped(bh)) |
| 1694 | continue; |
| 1695 | /* |
| 1696 | * If it's a fully non-blocking write attempt and we cannot |
| 1697 | * lock the buffer then redirty the page. Note that this can |
Jens Axboe | 5b0830c | 2009-09-23 19:37:09 +0200 | [diff] [blame] | 1698 | * potentially cause a busy-wait loop from writeback threads |
| 1699 | * and kswapd activity, but those code paths have their own |
| 1700 | * higher-level throttling. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1701 | */ |
Wu Fengguang | 1b430be | 2010-10-26 14:21:26 -0700 | [diff] [blame] | 1702 | if (wbc->sync_mode != WB_SYNC_NONE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1703 | lock_buffer(bh); |
Nick Piggin | ca5de40 | 2008-08-02 12:02:13 +0200 | [diff] [blame] | 1704 | } else if (!trylock_buffer(bh)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1705 | redirty_page_for_writepage(wbc, page); |
| 1706 | continue; |
| 1707 | } |
| 1708 | if (test_clear_buffer_dirty(bh)) { |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 1709 | mark_buffer_async_write_endio(bh, handler); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1710 | } else { |
| 1711 | unlock_buffer(bh); |
| 1712 | } |
| 1713 | } while ((bh = bh->b_this_page) != head); |
| 1714 | |
| 1715 | /* |
| 1716 | * The page and its buffers are protected by PageWriteback(), so we can |
| 1717 | * drop the bh refcounts early. |
| 1718 | */ |
| 1719 | BUG_ON(PageWriteback(page)); |
| 1720 | set_page_writeback(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1721 | |
| 1722 | do { |
| 1723 | struct buffer_head *next = bh->b_this_page; |
| 1724 | if (buffer_async_write(bh)) { |
Theodore Ts'o | a64c861 | 2009-03-27 22:14:10 -0400 | [diff] [blame] | 1725 | submit_bh(write_op, bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1726 | nr_underway++; |
| 1727 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1728 | bh = next; |
| 1729 | } while (bh != head); |
Andrew Morton | 05937ba | 2005-05-05 16:15:47 -0700 | [diff] [blame] | 1730 | unlock_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1731 | |
| 1732 | err = 0; |
| 1733 | done: |
| 1734 | if (nr_underway == 0) { |
| 1735 | /* |
| 1736 | * The page was marked dirty, but the buffers were |
| 1737 | * clean. Someone wrote them back by hand with |
| 1738 | * ll_rw_block/submit_bh. A rare case. |
| 1739 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1740 | end_page_writeback(page); |
Nick Piggin | 3d67f2d | 2007-05-06 14:49:05 -0700 | [diff] [blame] | 1741 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1742 | /* |
| 1743 | * The page and buffer_heads can be released at any time from |
| 1744 | * here on. |
| 1745 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1746 | } |
| 1747 | return err; |
| 1748 | |
| 1749 | recover: |
| 1750 | /* |
| 1751 | * ENOSPC, or some other error. We may already have added some |
| 1752 | * blocks to the file, so we need to write these out to avoid |
| 1753 | * exposing stale data. |
| 1754 | * The page is currently locked and not marked for writeback |
| 1755 | */ |
| 1756 | bh = head; |
| 1757 | /* Recovery: lock and submit the mapped buffers */ |
| 1758 | do { |
Alex Tomas | 29a814d | 2008-07-11 19:27:31 -0400 | [diff] [blame] | 1759 | if (buffer_mapped(bh) && buffer_dirty(bh) && |
| 1760 | !buffer_delay(bh)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1761 | lock_buffer(bh); |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 1762 | mark_buffer_async_write_endio(bh, handler); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1763 | } else { |
| 1764 | /* |
| 1765 | * The buffer may have been set dirty during |
| 1766 | * attachment to a dirty page. |
| 1767 | */ |
| 1768 | clear_buffer_dirty(bh); |
| 1769 | } |
| 1770 | } while ((bh = bh->b_this_page) != head); |
| 1771 | SetPageError(page); |
| 1772 | BUG_ON(PageWriteback(page)); |
Andrew Morton | 7e4c369 | 2007-05-08 00:23:27 -0700 | [diff] [blame] | 1773 | mapping_set_error(page->mapping, err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1774 | set_page_writeback(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1775 | do { |
| 1776 | struct buffer_head *next = bh->b_this_page; |
| 1777 | if (buffer_async_write(bh)) { |
| 1778 | clear_buffer_dirty(bh); |
Theodore Ts'o | a64c861 | 2009-03-27 22:14:10 -0400 | [diff] [blame] | 1779 | submit_bh(write_op, bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1780 | nr_underway++; |
| 1781 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1782 | bh = next; |
| 1783 | } while (bh != head); |
Nick Piggin | ffda9d3 | 2007-02-20 13:57:54 -0800 | [diff] [blame] | 1784 | unlock_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1785 | goto done; |
| 1786 | } |
| 1787 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1788 | /* |
| 1789 | * If a page has any new buffers, zero them out here, and mark them uptodate |
| 1790 | * and dirty so they'll be written out (in order to prevent uninitialised |
| 1791 | * block data from leaking). And clear the new bit. |
| 1792 | */ |
| 1793 | void page_zero_new_buffers(struct page *page, unsigned from, unsigned to) |
| 1794 | { |
| 1795 | unsigned int block_start, block_end; |
| 1796 | struct buffer_head *head, *bh; |
| 1797 | |
| 1798 | BUG_ON(!PageLocked(page)); |
| 1799 | if (!page_has_buffers(page)) |
| 1800 | return; |
| 1801 | |
| 1802 | bh = head = page_buffers(page); |
| 1803 | block_start = 0; |
| 1804 | do { |
| 1805 | block_end = block_start + bh->b_size; |
| 1806 | |
| 1807 | if (buffer_new(bh)) { |
| 1808 | if (block_end > from && block_start < to) { |
| 1809 | if (!PageUptodate(page)) { |
| 1810 | unsigned start, size; |
| 1811 | |
| 1812 | start = max(from, block_start); |
| 1813 | size = min(to, block_end) - start; |
| 1814 | |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 1815 | zero_user(page, start, size); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1816 | set_buffer_uptodate(bh); |
| 1817 | } |
| 1818 | |
| 1819 | clear_buffer_new(bh); |
| 1820 | mark_buffer_dirty(bh); |
| 1821 | } |
| 1822 | } |
| 1823 | |
| 1824 | block_start = block_end; |
| 1825 | bh = bh->b_this_page; |
| 1826 | } while (bh != head); |
| 1827 | } |
| 1828 | EXPORT_SYMBOL(page_zero_new_buffers); |
| 1829 | |
Christoph Hellwig | ebdec24 | 2010-10-06 10:47:23 +0200 | [diff] [blame] | 1830 | int __block_write_begin(struct page *page, loff_t pos, unsigned len, |
Christoph Hellwig | 6e1db88 | 2010-06-04 11:29:57 +0200 | [diff] [blame] | 1831 | get_block_t *get_block) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1832 | { |
Christoph Hellwig | ebdec24 | 2010-10-06 10:47:23 +0200 | [diff] [blame] | 1833 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); |
| 1834 | unsigned to = from + len; |
Christoph Hellwig | 6e1db88 | 2010-06-04 11:29:57 +0200 | [diff] [blame] | 1835 | struct inode *inode = page->mapping->host; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1836 | unsigned block_start, block_end; |
| 1837 | sector_t block; |
| 1838 | int err = 0; |
| 1839 | unsigned blocksize, bbits; |
| 1840 | struct buffer_head *bh, *head, *wait[2], **wait_bh=wait; |
| 1841 | |
| 1842 | BUG_ON(!PageLocked(page)); |
| 1843 | BUG_ON(from > PAGE_CACHE_SIZE); |
| 1844 | BUG_ON(to > PAGE_CACHE_SIZE); |
| 1845 | BUG_ON(from > to); |
| 1846 | |
| 1847 | blocksize = 1 << inode->i_blkbits; |
| 1848 | if (!page_has_buffers(page)) |
| 1849 | create_empty_buffers(page, blocksize, 0); |
| 1850 | head = page_buffers(page); |
| 1851 | |
| 1852 | bbits = inode->i_blkbits; |
| 1853 | block = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits); |
| 1854 | |
| 1855 | for(bh = head, block_start = 0; bh != head || !block_start; |
| 1856 | block++, block_start=block_end, bh = bh->b_this_page) { |
| 1857 | block_end = block_start + blocksize; |
| 1858 | if (block_end <= from || block_start >= to) { |
| 1859 | if (PageUptodate(page)) { |
| 1860 | if (!buffer_uptodate(bh)) |
| 1861 | set_buffer_uptodate(bh); |
| 1862 | } |
| 1863 | continue; |
| 1864 | } |
| 1865 | if (buffer_new(bh)) |
| 1866 | clear_buffer_new(bh); |
| 1867 | if (!buffer_mapped(bh)) { |
Badari Pulavarty | b0cf232 | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 1868 | WARN_ON(bh->b_size != blocksize); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1869 | err = get_block(inode, block, bh, 1); |
| 1870 | if (err) |
Nick Piggin | f3ddbdc | 2005-05-05 16:15:45 -0700 | [diff] [blame] | 1871 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1872 | if (buffer_new(bh)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1873 | unmap_underlying_metadata(bh->b_bdev, |
| 1874 | bh->b_blocknr); |
| 1875 | if (PageUptodate(page)) { |
Nick Piggin | 637aff4 | 2007-10-16 01:25:00 -0700 | [diff] [blame] | 1876 | clear_buffer_new(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1877 | set_buffer_uptodate(bh); |
Nick Piggin | 637aff4 | 2007-10-16 01:25:00 -0700 | [diff] [blame] | 1878 | mark_buffer_dirty(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1879 | continue; |
| 1880 | } |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 1881 | if (block_end > to || block_start < from) |
| 1882 | zero_user_segments(page, |
| 1883 | to, block_end, |
| 1884 | block_start, from); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1885 | continue; |
| 1886 | } |
| 1887 | } |
| 1888 | if (PageUptodate(page)) { |
| 1889 | if (!buffer_uptodate(bh)) |
| 1890 | set_buffer_uptodate(bh); |
| 1891 | continue; |
| 1892 | } |
| 1893 | if (!buffer_uptodate(bh) && !buffer_delay(bh) && |
David Chinner | 33a266d | 2007-02-12 00:51:41 -0800 | [diff] [blame] | 1894 | !buffer_unwritten(bh) && |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1895 | (block_start < from || block_end > to)) { |
| 1896 | ll_rw_block(READ, 1, &bh); |
| 1897 | *wait_bh++=bh; |
| 1898 | } |
| 1899 | } |
| 1900 | /* |
| 1901 | * If we issued read requests - let them complete. |
| 1902 | */ |
| 1903 | while(wait_bh > wait) { |
| 1904 | wait_on_buffer(*--wait_bh); |
| 1905 | if (!buffer_uptodate(*wait_bh)) |
Nick Piggin | f3ddbdc | 2005-05-05 16:15:45 -0700 | [diff] [blame] | 1906 | err = -EIO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1907 | } |
Jan Kara | f9f07b6 | 2011-06-14 00:58:27 +0200 | [diff] [blame] | 1908 | if (unlikely(err)) |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1909 | page_zero_new_buffers(page, from, to); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1910 | return err; |
| 1911 | } |
Christoph Hellwig | ebdec24 | 2010-10-06 10:47:23 +0200 | [diff] [blame] | 1912 | EXPORT_SYMBOL(__block_write_begin); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1913 | |
| 1914 | static int __block_commit_write(struct inode *inode, struct page *page, |
| 1915 | unsigned from, unsigned to) |
| 1916 | { |
| 1917 | unsigned block_start, block_end; |
| 1918 | int partial = 0; |
| 1919 | unsigned blocksize; |
| 1920 | struct buffer_head *bh, *head; |
| 1921 | |
| 1922 | blocksize = 1 << inode->i_blkbits; |
| 1923 | |
| 1924 | for(bh = head = page_buffers(page), block_start = 0; |
| 1925 | bh != head || !block_start; |
| 1926 | block_start=block_end, bh = bh->b_this_page) { |
| 1927 | block_end = block_start + blocksize; |
| 1928 | if (block_end <= from || block_start >= to) { |
| 1929 | if (!buffer_uptodate(bh)) |
| 1930 | partial = 1; |
| 1931 | } else { |
| 1932 | set_buffer_uptodate(bh); |
| 1933 | mark_buffer_dirty(bh); |
| 1934 | } |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1935 | clear_buffer_new(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1936 | } |
| 1937 | |
| 1938 | /* |
| 1939 | * If this is a partial write which happened to make all buffers |
| 1940 | * uptodate then we can optimize away a bogus readpage() for |
| 1941 | * the next read(). Here we 'discover' whether the page went |
| 1942 | * uptodate as a result of this (potentially partial) write. |
| 1943 | */ |
| 1944 | if (!partial) |
| 1945 | SetPageUptodate(page); |
| 1946 | return 0; |
| 1947 | } |
| 1948 | |
| 1949 | /* |
Christoph Hellwig | 155130a | 2010-06-04 11:29:58 +0200 | [diff] [blame] | 1950 | * block_write_begin takes care of the basic task of block allocation and |
| 1951 | * bringing partial write blocks uptodate first. |
| 1952 | * |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 1953 | * The filesystem needs to handle block truncation upon failure. |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1954 | */ |
Christoph Hellwig | 155130a | 2010-06-04 11:29:58 +0200 | [diff] [blame] | 1955 | int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len, |
| 1956 | unsigned flags, struct page **pagep, get_block_t *get_block) |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1957 | { |
Christoph Hellwig | 6e1db88 | 2010-06-04 11:29:57 +0200 | [diff] [blame] | 1958 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1959 | struct page *page; |
Christoph Hellwig | 6e1db88 | 2010-06-04 11:29:57 +0200 | [diff] [blame] | 1960 | int status; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1961 | |
Christoph Hellwig | 6e1db88 | 2010-06-04 11:29:57 +0200 | [diff] [blame] | 1962 | page = grab_cache_page_write_begin(mapping, index, flags); |
| 1963 | if (!page) |
| 1964 | return -ENOMEM; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1965 | |
Christoph Hellwig | 6e1db88 | 2010-06-04 11:29:57 +0200 | [diff] [blame] | 1966 | status = __block_write_begin(page, pos, len, get_block); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1967 | if (unlikely(status)) { |
Christoph Hellwig | 6e1db88 | 2010-06-04 11:29:57 +0200 | [diff] [blame] | 1968 | unlock_page(page); |
| 1969 | page_cache_release(page); |
| 1970 | page = NULL; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1971 | } |
| 1972 | |
Christoph Hellwig | 6e1db88 | 2010-06-04 11:29:57 +0200 | [diff] [blame] | 1973 | *pagep = page; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1974 | return status; |
| 1975 | } |
| 1976 | EXPORT_SYMBOL(block_write_begin); |
| 1977 | |
| 1978 | int block_write_end(struct file *file, struct address_space *mapping, |
| 1979 | loff_t pos, unsigned len, unsigned copied, |
| 1980 | struct page *page, void *fsdata) |
| 1981 | { |
| 1982 | struct inode *inode = mapping->host; |
| 1983 | unsigned start; |
| 1984 | |
| 1985 | start = pos & (PAGE_CACHE_SIZE - 1); |
| 1986 | |
| 1987 | if (unlikely(copied < len)) { |
| 1988 | /* |
| 1989 | * The buffers that were written will now be uptodate, so we |
| 1990 | * don't have to worry about a readpage reading them and |
| 1991 | * overwriting a partial write. However if we have encountered |
| 1992 | * a short write and only partially written into a buffer, it |
| 1993 | * will not be marked uptodate, so a readpage might come in and |
| 1994 | * destroy our partial write. |
| 1995 | * |
| 1996 | * Do the simplest thing, and just treat any short write to a |
| 1997 | * non uptodate page as a zero-length write, and force the |
| 1998 | * caller to redo the whole thing. |
| 1999 | */ |
| 2000 | if (!PageUptodate(page)) |
| 2001 | copied = 0; |
| 2002 | |
| 2003 | page_zero_new_buffers(page, start+copied, start+len); |
| 2004 | } |
| 2005 | flush_dcache_page(page); |
| 2006 | |
| 2007 | /* This could be a short (even 0-length) commit */ |
| 2008 | __block_commit_write(inode, page, start, start+copied); |
| 2009 | |
| 2010 | return copied; |
| 2011 | } |
| 2012 | EXPORT_SYMBOL(block_write_end); |
| 2013 | |
| 2014 | int generic_write_end(struct file *file, struct address_space *mapping, |
| 2015 | loff_t pos, unsigned len, unsigned copied, |
| 2016 | struct page *page, void *fsdata) |
| 2017 | { |
| 2018 | struct inode *inode = mapping->host; |
Jan Kara | c7d206b | 2008-07-11 19:27:31 -0400 | [diff] [blame] | 2019 | int i_size_changed = 0; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2020 | |
| 2021 | copied = block_write_end(file, mapping, pos, len, copied, page, fsdata); |
| 2022 | |
| 2023 | /* |
| 2024 | * No need to use i_size_read() here, the i_size |
| 2025 | * cannot change under us because we hold i_mutex. |
| 2026 | * |
| 2027 | * But it's important to update i_size while still holding page lock: |
| 2028 | * page writeout could otherwise come in and zero beyond i_size. |
| 2029 | */ |
| 2030 | if (pos+copied > inode->i_size) { |
| 2031 | i_size_write(inode, pos+copied); |
Jan Kara | c7d206b | 2008-07-11 19:27:31 -0400 | [diff] [blame] | 2032 | i_size_changed = 1; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2033 | } |
| 2034 | |
| 2035 | unlock_page(page); |
| 2036 | page_cache_release(page); |
| 2037 | |
Jan Kara | c7d206b | 2008-07-11 19:27:31 -0400 | [diff] [blame] | 2038 | /* |
| 2039 | * Don't mark the inode dirty under page lock. First, it unnecessarily |
| 2040 | * makes the holding time of page lock longer. Second, it forces lock |
| 2041 | * ordering of page lock and transaction start for journaling |
| 2042 | * filesystems. |
| 2043 | */ |
| 2044 | if (i_size_changed) |
| 2045 | mark_inode_dirty(inode); |
| 2046 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2047 | return copied; |
| 2048 | } |
| 2049 | EXPORT_SYMBOL(generic_write_end); |
| 2050 | |
| 2051 | /* |
Hisashi Hifumi | 8ab22b9 | 2008-07-28 15:46:36 -0700 | [diff] [blame] | 2052 | * block_is_partially_uptodate checks whether buffers within a page are |
| 2053 | * uptodate or not. |
| 2054 | * |
| 2055 | * Returns true if all buffers which correspond to a file portion |
| 2056 | * we want to read are uptodate. |
| 2057 | */ |
| 2058 | int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc, |
| 2059 | unsigned long from) |
| 2060 | { |
| 2061 | struct inode *inode = page->mapping->host; |
| 2062 | unsigned block_start, block_end, blocksize; |
| 2063 | unsigned to; |
| 2064 | struct buffer_head *bh, *head; |
| 2065 | int ret = 1; |
| 2066 | |
| 2067 | if (!page_has_buffers(page)) |
| 2068 | return 0; |
| 2069 | |
| 2070 | blocksize = 1 << inode->i_blkbits; |
| 2071 | to = min_t(unsigned, PAGE_CACHE_SIZE - from, desc->count); |
| 2072 | to = from + to; |
| 2073 | if (from < blocksize && to > PAGE_CACHE_SIZE - blocksize) |
| 2074 | return 0; |
| 2075 | |
| 2076 | head = page_buffers(page); |
| 2077 | bh = head; |
| 2078 | block_start = 0; |
| 2079 | do { |
| 2080 | block_end = block_start + blocksize; |
| 2081 | if (block_end > from && block_start < to) { |
| 2082 | if (!buffer_uptodate(bh)) { |
| 2083 | ret = 0; |
| 2084 | break; |
| 2085 | } |
| 2086 | if (block_end >= to) |
| 2087 | break; |
| 2088 | } |
| 2089 | block_start = block_end; |
| 2090 | bh = bh->b_this_page; |
| 2091 | } while (bh != head); |
| 2092 | |
| 2093 | return ret; |
| 2094 | } |
| 2095 | EXPORT_SYMBOL(block_is_partially_uptodate); |
| 2096 | |
| 2097 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2098 | * Generic "read page" function for block devices that have the normal |
| 2099 | * get_block functionality. This is most of the block device filesystems. |
| 2100 | * Reads the page asynchronously --- the unlock_buffer() and |
| 2101 | * set/clear_buffer_uptodate() functions propagate buffer state into the |
| 2102 | * page struct once IO has completed. |
| 2103 | */ |
| 2104 | int block_read_full_page(struct page *page, get_block_t *get_block) |
| 2105 | { |
| 2106 | struct inode *inode = page->mapping->host; |
| 2107 | sector_t iblock, lblock; |
| 2108 | struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; |
| 2109 | unsigned int blocksize; |
| 2110 | int nr, i; |
| 2111 | int fully_mapped = 1; |
| 2112 | |
Matt Mackall | cd7619d | 2005-05-01 08:59:01 -0700 | [diff] [blame] | 2113 | BUG_ON(!PageLocked(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2114 | blocksize = 1 << inode->i_blkbits; |
| 2115 | if (!page_has_buffers(page)) |
| 2116 | create_empty_buffers(page, blocksize, 0); |
| 2117 | head = page_buffers(page); |
| 2118 | |
| 2119 | iblock = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); |
| 2120 | lblock = (i_size_read(inode)+blocksize-1) >> inode->i_blkbits; |
| 2121 | bh = head; |
| 2122 | nr = 0; |
| 2123 | i = 0; |
| 2124 | |
| 2125 | do { |
| 2126 | if (buffer_uptodate(bh)) |
| 2127 | continue; |
| 2128 | |
| 2129 | if (!buffer_mapped(bh)) { |
Andrew Morton | c64610b | 2005-05-16 21:53:49 -0700 | [diff] [blame] | 2130 | int err = 0; |
| 2131 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2132 | fully_mapped = 0; |
| 2133 | if (iblock < lblock) { |
Badari Pulavarty | b0cf232 | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 2134 | WARN_ON(bh->b_size != blocksize); |
Andrew Morton | c64610b | 2005-05-16 21:53:49 -0700 | [diff] [blame] | 2135 | err = get_block(inode, iblock, bh, 0); |
| 2136 | if (err) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2137 | SetPageError(page); |
| 2138 | } |
| 2139 | if (!buffer_mapped(bh)) { |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2140 | zero_user(page, i * blocksize, blocksize); |
Andrew Morton | c64610b | 2005-05-16 21:53:49 -0700 | [diff] [blame] | 2141 | if (!err) |
| 2142 | set_buffer_uptodate(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2143 | continue; |
| 2144 | } |
| 2145 | /* |
| 2146 | * get_block() might have updated the buffer |
| 2147 | * synchronously |
| 2148 | */ |
| 2149 | if (buffer_uptodate(bh)) |
| 2150 | continue; |
| 2151 | } |
| 2152 | arr[nr++] = bh; |
| 2153 | } while (i++, iblock++, (bh = bh->b_this_page) != head); |
| 2154 | |
| 2155 | if (fully_mapped) |
| 2156 | SetPageMappedToDisk(page); |
| 2157 | |
| 2158 | if (!nr) { |
| 2159 | /* |
| 2160 | * All buffers are uptodate - we can set the page uptodate |
| 2161 | * as well. But not if get_block() returned an error. |
| 2162 | */ |
| 2163 | if (!PageError(page)) |
| 2164 | SetPageUptodate(page); |
| 2165 | unlock_page(page); |
| 2166 | return 0; |
| 2167 | } |
| 2168 | |
| 2169 | /* Stage two: lock the buffers */ |
| 2170 | for (i = 0; i < nr; i++) { |
| 2171 | bh = arr[i]; |
| 2172 | lock_buffer(bh); |
| 2173 | mark_buffer_async_read(bh); |
| 2174 | } |
| 2175 | |
| 2176 | /* |
| 2177 | * Stage 3: start the IO. Check for uptodateness |
| 2178 | * inside the buffer lock in case another process reading |
| 2179 | * the underlying blockdev brought it uptodate (the sct fix). |
| 2180 | */ |
| 2181 | for (i = 0; i < nr; i++) { |
| 2182 | bh = arr[i]; |
| 2183 | if (buffer_uptodate(bh)) |
| 2184 | end_buffer_async_read(bh, 1); |
| 2185 | else |
| 2186 | submit_bh(READ, bh); |
| 2187 | } |
| 2188 | return 0; |
| 2189 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2190 | EXPORT_SYMBOL(block_read_full_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2191 | |
| 2192 | /* utility function for filesystems that need to do work on expanding |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2193 | * truncates. Uses filesystem pagecache writes to allow the filesystem to |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2194 | * deal with the hole. |
| 2195 | */ |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2196 | int generic_cont_expand_simple(struct inode *inode, loff_t size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2197 | { |
| 2198 | struct address_space *mapping = inode->i_mapping; |
| 2199 | struct page *page; |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2200 | void *fsdata; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2201 | int err; |
| 2202 | |
npiggin@suse.de | c08d3b0 | 2009-08-21 02:35:06 +1000 | [diff] [blame] | 2203 | err = inode_newsize_ok(inode, size); |
| 2204 | if (err) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2205 | goto out; |
| 2206 | |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2207 | err = pagecache_write_begin(NULL, mapping, size, 0, |
| 2208 | AOP_FLAG_UNINTERRUPTIBLE|AOP_FLAG_CONT_EXPAND, |
| 2209 | &page, &fsdata); |
| 2210 | if (err) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2211 | goto out; |
OGAWA Hirofumi | 05eb0b5 | 2006-01-08 01:02:13 -0800 | [diff] [blame] | 2212 | |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2213 | err = pagecache_write_end(NULL, mapping, size, 0, 0, page, fsdata); |
| 2214 | BUG_ON(err > 0); |
OGAWA Hirofumi | 05eb0b5 | 2006-01-08 01:02:13 -0800 | [diff] [blame] | 2215 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2216 | out: |
| 2217 | return err; |
| 2218 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2219 | EXPORT_SYMBOL(generic_cont_expand_simple); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2220 | |
Adrian Bunk | f1e3af7 | 2008-04-29 00:59:01 -0700 | [diff] [blame] | 2221 | static int cont_expand_zero(struct file *file, struct address_space *mapping, |
| 2222 | loff_t pos, loff_t *bytes) |
OGAWA Hirofumi | 05eb0b5 | 2006-01-08 01:02:13 -0800 | [diff] [blame] | 2223 | { |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2224 | struct inode *inode = mapping->host; |
| 2225 | unsigned blocksize = 1 << inode->i_blkbits; |
| 2226 | struct page *page; |
| 2227 | void *fsdata; |
| 2228 | pgoff_t index, curidx; |
| 2229 | loff_t curpos; |
| 2230 | unsigned zerofrom, offset, len; |
| 2231 | int err = 0; |
OGAWA Hirofumi | 05eb0b5 | 2006-01-08 01:02:13 -0800 | [diff] [blame] | 2232 | |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2233 | index = pos >> PAGE_CACHE_SHIFT; |
| 2234 | offset = pos & ~PAGE_CACHE_MASK; |
| 2235 | |
| 2236 | while (index > (curidx = (curpos = *bytes)>>PAGE_CACHE_SHIFT)) { |
| 2237 | zerofrom = curpos & ~PAGE_CACHE_MASK; |
| 2238 | if (zerofrom & (blocksize-1)) { |
| 2239 | *bytes |= (blocksize-1); |
| 2240 | (*bytes)++; |
| 2241 | } |
| 2242 | len = PAGE_CACHE_SIZE - zerofrom; |
| 2243 | |
| 2244 | err = pagecache_write_begin(file, mapping, curpos, len, |
| 2245 | AOP_FLAG_UNINTERRUPTIBLE, |
| 2246 | &page, &fsdata); |
| 2247 | if (err) |
| 2248 | goto out; |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2249 | zero_user(page, zerofrom, len); |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2250 | err = pagecache_write_end(file, mapping, curpos, len, len, |
| 2251 | page, fsdata); |
| 2252 | if (err < 0) |
| 2253 | goto out; |
| 2254 | BUG_ON(err != len); |
| 2255 | err = 0; |
OGAWA Hirofumi | 061e974 | 2008-04-28 02:16:28 -0700 | [diff] [blame] | 2256 | |
| 2257 | balance_dirty_pages_ratelimited(mapping); |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2258 | } |
| 2259 | |
| 2260 | /* page covers the boundary, find the boundary offset */ |
| 2261 | if (index == curidx) { |
| 2262 | zerofrom = curpos & ~PAGE_CACHE_MASK; |
| 2263 | /* if we will expand the thing last block will be filled */ |
| 2264 | if (offset <= zerofrom) { |
| 2265 | goto out; |
| 2266 | } |
| 2267 | if (zerofrom & (blocksize-1)) { |
| 2268 | *bytes |= (blocksize-1); |
| 2269 | (*bytes)++; |
| 2270 | } |
| 2271 | len = offset - zerofrom; |
| 2272 | |
| 2273 | err = pagecache_write_begin(file, mapping, curpos, len, |
| 2274 | AOP_FLAG_UNINTERRUPTIBLE, |
| 2275 | &page, &fsdata); |
| 2276 | if (err) |
| 2277 | goto out; |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2278 | zero_user(page, zerofrom, len); |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2279 | err = pagecache_write_end(file, mapping, curpos, len, len, |
| 2280 | page, fsdata); |
| 2281 | if (err < 0) |
| 2282 | goto out; |
| 2283 | BUG_ON(err != len); |
| 2284 | err = 0; |
| 2285 | } |
| 2286 | out: |
| 2287 | return err; |
OGAWA Hirofumi | 05eb0b5 | 2006-01-08 01:02:13 -0800 | [diff] [blame] | 2288 | } |
| 2289 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2290 | /* |
| 2291 | * For moronic filesystems that do not allow holes in file. |
| 2292 | * We may have to extend the file. |
| 2293 | */ |
Christoph Hellwig | 282dc17 | 2010-06-04 11:29:55 +0200 | [diff] [blame] | 2294 | int cont_write_begin(struct file *file, struct address_space *mapping, |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2295 | loff_t pos, unsigned len, unsigned flags, |
| 2296 | struct page **pagep, void **fsdata, |
| 2297 | get_block_t *get_block, loff_t *bytes) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2298 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2299 | struct inode *inode = mapping->host; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2300 | unsigned blocksize = 1 << inode->i_blkbits; |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2301 | unsigned zerofrom; |
| 2302 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2303 | |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2304 | err = cont_expand_zero(file, mapping, pos, bytes); |
| 2305 | if (err) |
Christoph Hellwig | 155130a | 2010-06-04 11:29:58 +0200 | [diff] [blame] | 2306 | return err; |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2307 | |
| 2308 | zerofrom = *bytes & ~PAGE_CACHE_MASK; |
| 2309 | if (pos+len > *bytes && zerofrom & (blocksize-1)) { |
| 2310 | *bytes |= (blocksize-1); |
| 2311 | (*bytes)++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2312 | } |
| 2313 | |
Christoph Hellwig | 155130a | 2010-06-04 11:29:58 +0200 | [diff] [blame] | 2314 | return block_write_begin(mapping, pos, len, flags, pagep, get_block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2315 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2316 | EXPORT_SYMBOL(cont_write_begin); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2317 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2318 | int block_commit_write(struct page *page, unsigned from, unsigned to) |
| 2319 | { |
| 2320 | struct inode *inode = page->mapping->host; |
| 2321 | __block_commit_write(inode,page,from,to); |
| 2322 | return 0; |
| 2323 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2324 | EXPORT_SYMBOL(block_commit_write); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2325 | |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2326 | /* |
| 2327 | * block_page_mkwrite() is not allowed to change the file size as it gets |
| 2328 | * called from a page fault handler when a page is first dirtied. Hence we must |
| 2329 | * be careful to check for EOF conditions here. We set the page up correctly |
| 2330 | * for a written page which means we get ENOSPC checking when writing into |
| 2331 | * holes and correct delalloc and unwritten extent mapping on filesystems that |
| 2332 | * support these features. |
| 2333 | * |
| 2334 | * We are not allowed to take the i_mutex here so we have to play games to |
| 2335 | * protect against truncate races as the page could now be beyond EOF. Because |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 2336 | * truncate writes the inode size before removing pages, once we have the |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2337 | * page lock we can determine safely if the page is beyond EOF. If it is not |
| 2338 | * beyond EOF, then the page is guaranteed safe against truncation until we |
| 2339 | * unlock the page. |
Jan Kara | ea13a86 | 2011-05-24 00:23:35 +0200 | [diff] [blame] | 2340 | * |
| 2341 | * Direct callers of this function should call vfs_check_frozen() so that page |
| 2342 | * fault does not busyloop until the fs is thawed. |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2343 | */ |
Jan Kara | 24da4fa | 2011-05-24 00:23:34 +0200 | [diff] [blame] | 2344 | int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, |
| 2345 | get_block_t get_block) |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2346 | { |
Nick Piggin | c2ec175 | 2009-03-31 15:23:21 -0700 | [diff] [blame] | 2347 | struct page *page = vmf->page; |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2348 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
| 2349 | unsigned long end; |
| 2350 | loff_t size; |
Jan Kara | 24da4fa | 2011-05-24 00:23:34 +0200 | [diff] [blame] | 2351 | int ret; |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2352 | |
| 2353 | lock_page(page); |
| 2354 | size = i_size_read(inode); |
| 2355 | if ((page->mapping != inode->i_mapping) || |
Nick Piggin | 1833633 | 2007-07-20 00:31:45 -0700 | [diff] [blame] | 2356 | (page_offset(page) > size)) { |
Jan Kara | 24da4fa | 2011-05-24 00:23:34 +0200 | [diff] [blame] | 2357 | /* We overload EFAULT to mean page got truncated */ |
| 2358 | ret = -EFAULT; |
| 2359 | goto out_unlock; |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2360 | } |
| 2361 | |
| 2362 | /* page is wholly or partially inside EOF */ |
| 2363 | if (((page->index + 1) << PAGE_CACHE_SHIFT) > size) |
| 2364 | end = size & ~PAGE_CACHE_MASK; |
| 2365 | else |
| 2366 | end = PAGE_CACHE_SIZE; |
| 2367 | |
Christoph Hellwig | ebdec24 | 2010-10-06 10:47:23 +0200 | [diff] [blame] | 2368 | ret = __block_write_begin(page, 0, end, get_block); |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2369 | if (!ret) |
| 2370 | ret = block_commit_write(page, 0, end); |
| 2371 | |
Jan Kara | 24da4fa | 2011-05-24 00:23:34 +0200 | [diff] [blame] | 2372 | if (unlikely(ret < 0)) |
| 2373 | goto out_unlock; |
Jan Kara | ea13a86 | 2011-05-24 00:23:35 +0200 | [diff] [blame] | 2374 | /* |
| 2375 | * Freezing in progress? We check after the page is marked dirty and |
| 2376 | * with page lock held so if the test here fails, we are sure freezing |
| 2377 | * code will wait during syncing until the page fault is done - at that |
| 2378 | * point page will be dirty and unlocked so freezing code will write it |
| 2379 | * and writeprotect it again. |
| 2380 | */ |
| 2381 | set_page_dirty(page); |
| 2382 | if (inode->i_sb->s_frozen != SB_UNFROZEN) { |
| 2383 | ret = -EAGAIN; |
| 2384 | goto out_unlock; |
| 2385 | } |
Darrick J. Wong | d76ee18 | 2011-05-27 12:23:41 -0700 | [diff] [blame] | 2386 | wait_on_page_writeback(page); |
Jan Kara | 24da4fa | 2011-05-24 00:23:34 +0200 | [diff] [blame] | 2387 | return 0; |
| 2388 | out_unlock: |
| 2389 | unlock_page(page); |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2390 | return ret; |
| 2391 | } |
Jan Kara | 24da4fa | 2011-05-24 00:23:34 +0200 | [diff] [blame] | 2392 | EXPORT_SYMBOL(__block_page_mkwrite); |
| 2393 | |
| 2394 | int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, |
| 2395 | get_block_t get_block) |
| 2396 | { |
Jan Kara | ea13a86 | 2011-05-24 00:23:35 +0200 | [diff] [blame] | 2397 | int ret; |
| 2398 | struct super_block *sb = vma->vm_file->f_path.dentry->d_inode->i_sb; |
Jan Kara | 24da4fa | 2011-05-24 00:23:34 +0200 | [diff] [blame] | 2399 | |
Jan Kara | ea13a86 | 2011-05-24 00:23:35 +0200 | [diff] [blame] | 2400 | /* |
| 2401 | * This check is racy but catches the common case. The check in |
| 2402 | * __block_page_mkwrite() is reliable. |
| 2403 | */ |
| 2404 | vfs_check_frozen(sb, SB_FREEZE_WRITE); |
| 2405 | ret = __block_page_mkwrite(vma, vmf, get_block); |
Jan Kara | 24da4fa | 2011-05-24 00:23:34 +0200 | [diff] [blame] | 2406 | return block_page_mkwrite_return(ret); |
| 2407 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2408 | EXPORT_SYMBOL(block_page_mkwrite); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2409 | |
| 2410 | /* |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2411 | * nobh_write_begin()'s prereads are special: the buffer_heads are freed |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2412 | * immediately, while under the page lock. So it needs a special end_io |
| 2413 | * handler which does not touch the bh after unlocking it. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2414 | */ |
| 2415 | static void end_buffer_read_nobh(struct buffer_head *bh, int uptodate) |
| 2416 | { |
Dmitry Monakhov | 68671f3 | 2007-10-16 01:24:47 -0700 | [diff] [blame] | 2417 | __end_buffer_read_notouch(bh, uptodate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2418 | } |
| 2419 | |
| 2420 | /* |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2421 | * Attach the singly-linked list of buffers created by nobh_write_begin, to |
| 2422 | * the page (converting it to circular linked list and taking care of page |
| 2423 | * dirty races). |
| 2424 | */ |
| 2425 | static void attach_nobh_buffers(struct page *page, struct buffer_head *head) |
| 2426 | { |
| 2427 | struct buffer_head *bh; |
| 2428 | |
| 2429 | BUG_ON(!PageLocked(page)); |
| 2430 | |
| 2431 | spin_lock(&page->mapping->private_lock); |
| 2432 | bh = head; |
| 2433 | do { |
| 2434 | if (PageDirty(page)) |
| 2435 | set_buffer_dirty(bh); |
| 2436 | if (!bh->b_this_page) |
| 2437 | bh->b_this_page = head; |
| 2438 | bh = bh->b_this_page; |
| 2439 | } while (bh != head); |
| 2440 | attach_page_buffers(page, head); |
| 2441 | spin_unlock(&page->mapping->private_lock); |
| 2442 | } |
| 2443 | |
| 2444 | /* |
Christoph Hellwig | ea0f04e | 2010-06-04 11:29:54 +0200 | [diff] [blame] | 2445 | * On entry, the page is fully not uptodate. |
| 2446 | * On exit the page is fully uptodate in the areas outside (from,to) |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 2447 | * The filesystem needs to handle block truncation upon failure. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2448 | */ |
Christoph Hellwig | ea0f04e | 2010-06-04 11:29:54 +0200 | [diff] [blame] | 2449 | int nobh_write_begin(struct address_space *mapping, |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2450 | loff_t pos, unsigned len, unsigned flags, |
| 2451 | struct page **pagep, void **fsdata, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2452 | get_block_t *get_block) |
| 2453 | { |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2454 | struct inode *inode = mapping->host; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2455 | const unsigned blkbits = inode->i_blkbits; |
| 2456 | const unsigned blocksize = 1 << blkbits; |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2457 | struct buffer_head *head, *bh; |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2458 | struct page *page; |
| 2459 | pgoff_t index; |
| 2460 | unsigned from, to; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2461 | unsigned block_in_page; |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2462 | unsigned block_start, block_end; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2463 | sector_t block_in_file; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2464 | int nr_reads = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2465 | int ret = 0; |
| 2466 | int is_mapped_to_disk = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2467 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2468 | index = pos >> PAGE_CACHE_SHIFT; |
| 2469 | from = pos & (PAGE_CACHE_SIZE - 1); |
| 2470 | to = from + len; |
| 2471 | |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 2472 | page = grab_cache_page_write_begin(mapping, index, flags); |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2473 | if (!page) |
| 2474 | return -ENOMEM; |
| 2475 | *pagep = page; |
| 2476 | *fsdata = NULL; |
| 2477 | |
| 2478 | if (page_has_buffers(page)) { |
Namhyung Kim | 309f77a | 2010-10-25 15:01:12 +0900 | [diff] [blame] | 2479 | ret = __block_write_begin(page, pos, len, get_block); |
| 2480 | if (unlikely(ret)) |
| 2481 | goto out_release; |
| 2482 | return ret; |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2483 | } |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2484 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2485 | if (PageMappedToDisk(page)) |
| 2486 | return 0; |
| 2487 | |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2488 | /* |
| 2489 | * Allocate buffers so that we can keep track of state, and potentially |
| 2490 | * attach them to the page if an error occurs. In the common case of |
| 2491 | * no error, they will just be freed again without ever being attached |
| 2492 | * to the page (which is all OK, because we're under the page lock). |
| 2493 | * |
| 2494 | * Be careful: the buffer linked list is a NULL terminated one, rather |
| 2495 | * than the circular one we're used to. |
| 2496 | */ |
| 2497 | head = alloc_page_buffers(page, blocksize, 0); |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2498 | if (!head) { |
| 2499 | ret = -ENOMEM; |
| 2500 | goto out_release; |
| 2501 | } |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2502 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2503 | block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2504 | |
| 2505 | /* |
| 2506 | * We loop across all blocks in the page, whether or not they are |
| 2507 | * part of the affected region. This is so we can discover if the |
| 2508 | * page is fully mapped-to-disk. |
| 2509 | */ |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2510 | for (block_start = 0, block_in_page = 0, bh = head; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2511 | block_start < PAGE_CACHE_SIZE; |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2512 | block_in_page++, block_start += blocksize, bh = bh->b_this_page) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2513 | int create; |
| 2514 | |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2515 | block_end = block_start + blocksize; |
| 2516 | bh->b_state = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2517 | create = 1; |
| 2518 | if (block_start >= to) |
| 2519 | create = 0; |
| 2520 | ret = get_block(inode, block_in_file + block_in_page, |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2521 | bh, create); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2522 | if (ret) |
| 2523 | goto failed; |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2524 | if (!buffer_mapped(bh)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2525 | is_mapped_to_disk = 0; |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2526 | if (buffer_new(bh)) |
| 2527 | unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); |
| 2528 | if (PageUptodate(page)) { |
| 2529 | set_buffer_uptodate(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2530 | continue; |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2531 | } |
| 2532 | if (buffer_new(bh) || !buffer_mapped(bh)) { |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2533 | zero_user_segments(page, block_start, from, |
| 2534 | to, block_end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2535 | continue; |
| 2536 | } |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2537 | if (buffer_uptodate(bh)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2538 | continue; /* reiserfs does this */ |
| 2539 | if (block_start < from || block_end > to) { |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2540 | lock_buffer(bh); |
| 2541 | bh->b_end_io = end_buffer_read_nobh; |
| 2542 | submit_bh(READ, bh); |
| 2543 | nr_reads++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2544 | } |
| 2545 | } |
| 2546 | |
| 2547 | if (nr_reads) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2548 | /* |
| 2549 | * The page is locked, so these buffers are protected from |
| 2550 | * any VM or truncate activity. Hence we don't need to care |
| 2551 | * for the buffer_head refcounts. |
| 2552 | */ |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2553 | for (bh = head; bh; bh = bh->b_this_page) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2554 | wait_on_buffer(bh); |
| 2555 | if (!buffer_uptodate(bh)) |
| 2556 | ret = -EIO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2557 | } |
| 2558 | if (ret) |
| 2559 | goto failed; |
| 2560 | } |
| 2561 | |
| 2562 | if (is_mapped_to_disk) |
| 2563 | SetPageMappedToDisk(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2564 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2565 | *fsdata = head; /* to be released by nobh_write_end */ |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2566 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2567 | return 0; |
| 2568 | |
| 2569 | failed: |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2570 | BUG_ON(!ret); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2571 | /* |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2572 | * Error recovery is a bit difficult. We need to zero out blocks that |
| 2573 | * were newly allocated, and dirty them to ensure they get written out. |
| 2574 | * Buffers need to be attached to the page at this point, otherwise |
| 2575 | * the handling of potential IO errors during writeout would be hard |
| 2576 | * (could try doing synchronous writeout, but what if that fails too?) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2577 | */ |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2578 | attach_nobh_buffers(page, head); |
| 2579 | page_zero_new_buffers(page, from, to); |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2580 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2581 | out_release: |
| 2582 | unlock_page(page); |
| 2583 | page_cache_release(page); |
| 2584 | *pagep = NULL; |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2585 | |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 2586 | return ret; |
| 2587 | } |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2588 | EXPORT_SYMBOL(nobh_write_begin); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2589 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2590 | int nobh_write_end(struct file *file, struct address_space *mapping, |
| 2591 | loff_t pos, unsigned len, unsigned copied, |
| 2592 | struct page *page, void *fsdata) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2593 | { |
| 2594 | struct inode *inode = page->mapping->host; |
Nick Piggin | efdc313 | 2007-10-21 06:57:41 +0200 | [diff] [blame] | 2595 | struct buffer_head *head = fsdata; |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2596 | struct buffer_head *bh; |
Dmitri Monakhov | 5b41e74 | 2008-03-28 14:15:52 -0700 | [diff] [blame] | 2597 | BUG_ON(fsdata != NULL && page_has_buffers(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2598 | |
Dave Kleikamp | d4cf109 | 2009-02-06 14:59:26 -0600 | [diff] [blame] | 2599 | if (unlikely(copied < len) && head) |
Dmitri Monakhov | 5b41e74 | 2008-03-28 14:15:52 -0700 | [diff] [blame] | 2600 | attach_nobh_buffers(page, head); |
| 2601 | if (page_has_buffers(page)) |
| 2602 | return generic_write_end(file, mapping, pos, len, |
| 2603 | copied, page, fsdata); |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2604 | |
Nick Piggin | 22c8ca7 | 2007-02-20 13:58:09 -0800 | [diff] [blame] | 2605 | SetPageUptodate(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2606 | set_page_dirty(page); |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2607 | if (pos+copied > inode->i_size) { |
| 2608 | i_size_write(inode, pos+copied); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2609 | mark_inode_dirty(inode); |
| 2610 | } |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2611 | |
| 2612 | unlock_page(page); |
| 2613 | page_cache_release(page); |
| 2614 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2615 | while (head) { |
| 2616 | bh = head; |
| 2617 | head = head->b_this_page; |
| 2618 | free_buffer_head(bh); |
| 2619 | } |
| 2620 | |
| 2621 | return copied; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2622 | } |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2623 | EXPORT_SYMBOL(nobh_write_end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2624 | |
| 2625 | /* |
| 2626 | * nobh_writepage() - based on block_full_write_page() except |
| 2627 | * that it tries to operate without attaching bufferheads to |
| 2628 | * the page. |
| 2629 | */ |
| 2630 | int nobh_writepage(struct page *page, get_block_t *get_block, |
| 2631 | struct writeback_control *wbc) |
| 2632 | { |
| 2633 | struct inode * const inode = page->mapping->host; |
| 2634 | loff_t i_size = i_size_read(inode); |
| 2635 | const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; |
| 2636 | unsigned offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2637 | int ret; |
| 2638 | |
| 2639 | /* Is the page fully inside i_size? */ |
| 2640 | if (page->index < end_index) |
| 2641 | goto out; |
| 2642 | |
| 2643 | /* Is the page fully outside i_size? (truncate in progress) */ |
| 2644 | offset = i_size & (PAGE_CACHE_SIZE-1); |
| 2645 | if (page->index >= end_index+1 || !offset) { |
| 2646 | /* |
| 2647 | * The page may have dirty, unmapped buffers. For example, |
| 2648 | * they may have been added in ext3_writepage(). Make them |
| 2649 | * freeable here, so the page does not leak. |
| 2650 | */ |
| 2651 | #if 0 |
| 2652 | /* Not really sure about this - do we need this ? */ |
| 2653 | if (page->mapping->a_ops->invalidatepage) |
| 2654 | page->mapping->a_ops->invalidatepage(page, offset); |
| 2655 | #endif |
| 2656 | unlock_page(page); |
| 2657 | return 0; /* don't care */ |
| 2658 | } |
| 2659 | |
| 2660 | /* |
| 2661 | * The page straddles i_size. It must be zeroed out on each and every |
| 2662 | * writepage invocation because it may be mmapped. "A file is mapped |
| 2663 | * in multiples of the page size. For a file that is not a multiple of |
| 2664 | * the page size, the remaining memory is zeroed when mapped, and |
| 2665 | * writes to that region are not written out to the file." |
| 2666 | */ |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2667 | zero_user_segment(page, offset, PAGE_CACHE_SIZE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2668 | out: |
| 2669 | ret = mpage_writepage(page, get_block, wbc); |
| 2670 | if (ret == -EAGAIN) |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 2671 | ret = __block_write_full_page(inode, page, get_block, wbc, |
| 2672 | end_buffer_async_write); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2673 | return ret; |
| 2674 | } |
| 2675 | EXPORT_SYMBOL(nobh_writepage); |
| 2676 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2677 | int nobh_truncate_page(struct address_space *mapping, |
| 2678 | loff_t from, get_block_t *get_block) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2679 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2680 | pgoff_t index = from >> PAGE_CACHE_SHIFT; |
| 2681 | unsigned offset = from & (PAGE_CACHE_SIZE-1); |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2682 | unsigned blocksize; |
| 2683 | sector_t iblock; |
| 2684 | unsigned length, pos; |
| 2685 | struct inode *inode = mapping->host; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2686 | struct page *page; |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2687 | struct buffer_head map_bh; |
| 2688 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2689 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2690 | blocksize = 1 << inode->i_blkbits; |
| 2691 | length = offset & (blocksize - 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2692 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2693 | /* Block boundary? Nothing to do */ |
| 2694 | if (!length) |
| 2695 | return 0; |
| 2696 | |
| 2697 | length = blocksize - length; |
| 2698 | iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits); |
| 2699 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2700 | page = grab_cache_page(mapping, index); |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2701 | err = -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2702 | if (!page) |
| 2703 | goto out; |
| 2704 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2705 | if (page_has_buffers(page)) { |
| 2706 | has_buffers: |
| 2707 | unlock_page(page); |
| 2708 | page_cache_release(page); |
| 2709 | return block_truncate_page(mapping, from, get_block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2710 | } |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2711 | |
| 2712 | /* Find the buffer that contains "offset" */ |
| 2713 | pos = blocksize; |
| 2714 | while (offset >= pos) { |
| 2715 | iblock++; |
| 2716 | pos += blocksize; |
| 2717 | } |
| 2718 | |
Theodore Ts'o | 460bcf5 | 2009-05-12 07:37:56 -0400 | [diff] [blame] | 2719 | map_bh.b_size = blocksize; |
| 2720 | map_bh.b_state = 0; |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2721 | err = get_block(inode, iblock, &map_bh, 0); |
| 2722 | if (err) |
| 2723 | goto unlock; |
| 2724 | /* unmapped? It's a hole - nothing to do */ |
| 2725 | if (!buffer_mapped(&map_bh)) |
| 2726 | goto unlock; |
| 2727 | |
| 2728 | /* Ok, it's mapped. Make sure it's up-to-date */ |
| 2729 | if (!PageUptodate(page)) { |
| 2730 | err = mapping->a_ops->readpage(NULL, page); |
| 2731 | if (err) { |
| 2732 | page_cache_release(page); |
| 2733 | goto out; |
| 2734 | } |
| 2735 | lock_page(page); |
| 2736 | if (!PageUptodate(page)) { |
| 2737 | err = -EIO; |
| 2738 | goto unlock; |
| 2739 | } |
| 2740 | if (page_has_buffers(page)) |
| 2741 | goto has_buffers; |
| 2742 | } |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2743 | zero_user(page, offset, length); |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2744 | set_page_dirty(page); |
| 2745 | err = 0; |
| 2746 | |
| 2747 | unlock: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2748 | unlock_page(page); |
| 2749 | page_cache_release(page); |
| 2750 | out: |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2751 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2752 | } |
| 2753 | EXPORT_SYMBOL(nobh_truncate_page); |
| 2754 | |
| 2755 | int block_truncate_page(struct address_space *mapping, |
| 2756 | loff_t from, get_block_t *get_block) |
| 2757 | { |
| 2758 | pgoff_t index = from >> PAGE_CACHE_SHIFT; |
| 2759 | unsigned offset = from & (PAGE_CACHE_SIZE-1); |
| 2760 | unsigned blocksize; |
Andrew Morton | 54b21a7 | 2006-01-08 01:03:05 -0800 | [diff] [blame] | 2761 | sector_t iblock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2762 | unsigned length, pos; |
| 2763 | struct inode *inode = mapping->host; |
| 2764 | struct page *page; |
| 2765 | struct buffer_head *bh; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2766 | int err; |
| 2767 | |
| 2768 | blocksize = 1 << inode->i_blkbits; |
| 2769 | length = offset & (blocksize - 1); |
| 2770 | |
| 2771 | /* Block boundary? Nothing to do */ |
| 2772 | if (!length) |
| 2773 | return 0; |
| 2774 | |
| 2775 | length = blocksize - length; |
Andrew Morton | 54b21a7 | 2006-01-08 01:03:05 -0800 | [diff] [blame] | 2776 | iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2777 | |
| 2778 | page = grab_cache_page(mapping, index); |
| 2779 | err = -ENOMEM; |
| 2780 | if (!page) |
| 2781 | goto out; |
| 2782 | |
| 2783 | if (!page_has_buffers(page)) |
| 2784 | create_empty_buffers(page, blocksize, 0); |
| 2785 | |
| 2786 | /* Find the buffer that contains "offset" */ |
| 2787 | bh = page_buffers(page); |
| 2788 | pos = blocksize; |
| 2789 | while (offset >= pos) { |
| 2790 | bh = bh->b_this_page; |
| 2791 | iblock++; |
| 2792 | pos += blocksize; |
| 2793 | } |
| 2794 | |
| 2795 | err = 0; |
| 2796 | if (!buffer_mapped(bh)) { |
Badari Pulavarty | b0cf232 | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 2797 | WARN_ON(bh->b_size != blocksize); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2798 | err = get_block(inode, iblock, bh, 0); |
| 2799 | if (err) |
| 2800 | goto unlock; |
| 2801 | /* unmapped? It's a hole - nothing to do */ |
| 2802 | if (!buffer_mapped(bh)) |
| 2803 | goto unlock; |
| 2804 | } |
| 2805 | |
| 2806 | /* Ok, it's mapped. Make sure it's up-to-date */ |
| 2807 | if (PageUptodate(page)) |
| 2808 | set_buffer_uptodate(bh); |
| 2809 | |
David Chinner | 33a266d | 2007-02-12 00:51:41 -0800 | [diff] [blame] | 2810 | if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_unwritten(bh)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2811 | err = -EIO; |
| 2812 | ll_rw_block(READ, 1, &bh); |
| 2813 | wait_on_buffer(bh); |
| 2814 | /* Uhhuh. Read error. Complain and punt. */ |
| 2815 | if (!buffer_uptodate(bh)) |
| 2816 | goto unlock; |
| 2817 | } |
| 2818 | |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2819 | zero_user(page, offset, length); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2820 | mark_buffer_dirty(bh); |
| 2821 | err = 0; |
| 2822 | |
| 2823 | unlock: |
| 2824 | unlock_page(page); |
| 2825 | page_cache_release(page); |
| 2826 | out: |
| 2827 | return err; |
| 2828 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2829 | EXPORT_SYMBOL(block_truncate_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2830 | |
| 2831 | /* |
| 2832 | * The generic ->writepage function for buffer-backed address_spaces |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 2833 | * this form passes in the end_io handler used to finish the IO. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2834 | */ |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 2835 | int block_write_full_page_endio(struct page *page, get_block_t *get_block, |
| 2836 | struct writeback_control *wbc, bh_end_io_t *handler) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2837 | { |
| 2838 | struct inode * const inode = page->mapping->host; |
| 2839 | loff_t i_size = i_size_read(inode); |
| 2840 | const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; |
| 2841 | unsigned offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2842 | |
| 2843 | /* Is the page fully inside i_size? */ |
| 2844 | if (page->index < end_index) |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 2845 | return __block_write_full_page(inode, page, get_block, wbc, |
| 2846 | handler); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2847 | |
| 2848 | /* Is the page fully outside i_size? (truncate in progress) */ |
| 2849 | offset = i_size & (PAGE_CACHE_SIZE-1); |
| 2850 | if (page->index >= end_index+1 || !offset) { |
| 2851 | /* |
| 2852 | * The page may have dirty, unmapped buffers. For example, |
| 2853 | * they may have been added in ext3_writepage(). Make them |
| 2854 | * freeable here, so the page does not leak. |
| 2855 | */ |
Jan Kara | aaa4059 | 2005-10-30 15:00:16 -0800 | [diff] [blame] | 2856 | do_invalidatepage(page, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2857 | unlock_page(page); |
| 2858 | return 0; /* don't care */ |
| 2859 | } |
| 2860 | |
| 2861 | /* |
| 2862 | * The page straddles i_size. It must be zeroed out on each and every |
Adam Buchbinder | 2a61aa4 | 2009-12-11 16:35:40 -0500 | [diff] [blame] | 2863 | * writepage invocation because it may be mmapped. "A file is mapped |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2864 | * in multiples of the page size. For a file that is not a multiple of |
| 2865 | * the page size, the remaining memory is zeroed when mapped, and |
| 2866 | * writes to that region are not written out to the file." |
| 2867 | */ |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2868 | zero_user_segment(page, offset, PAGE_CACHE_SIZE); |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 2869 | return __block_write_full_page(inode, page, get_block, wbc, handler); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2870 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2871 | EXPORT_SYMBOL(block_write_full_page_endio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2872 | |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 2873 | /* |
| 2874 | * The generic ->writepage function for buffer-backed address_spaces |
| 2875 | */ |
| 2876 | int block_write_full_page(struct page *page, get_block_t *get_block, |
| 2877 | struct writeback_control *wbc) |
| 2878 | { |
| 2879 | return block_write_full_page_endio(page, get_block, wbc, |
| 2880 | end_buffer_async_write); |
| 2881 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2882 | EXPORT_SYMBOL(block_write_full_page); |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 2883 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2884 | sector_t generic_block_bmap(struct address_space *mapping, sector_t block, |
| 2885 | get_block_t *get_block) |
| 2886 | { |
| 2887 | struct buffer_head tmp; |
| 2888 | struct inode *inode = mapping->host; |
| 2889 | tmp.b_state = 0; |
| 2890 | tmp.b_blocknr = 0; |
Badari Pulavarty | b0cf232 | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 2891 | tmp.b_size = 1 << inode->i_blkbits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2892 | get_block(inode, block, &tmp, 0); |
| 2893 | return tmp.b_blocknr; |
| 2894 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2895 | EXPORT_SYMBOL(generic_block_bmap); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2896 | |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 2897 | static void end_bio_bh_io_sync(struct bio *bio, int err) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2898 | { |
| 2899 | struct buffer_head *bh = bio->bi_private; |
| 2900 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2901 | if (err == -EOPNOTSUPP) { |
| 2902 | set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2903 | } |
| 2904 | |
Keith Mannthey | 08bafc0 | 2008-11-25 10:24:35 +0100 | [diff] [blame] | 2905 | if (unlikely (test_bit(BIO_QUIET,&bio->bi_flags))) |
| 2906 | set_bit(BH_Quiet, &bh->b_state); |
| 2907 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2908 | bh->b_end_io(bh, test_bit(BIO_UPTODATE, &bio->bi_flags)); |
| 2909 | bio_put(bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2910 | } |
| 2911 | |
| 2912 | int submit_bh(int rw, struct buffer_head * bh) |
| 2913 | { |
| 2914 | struct bio *bio; |
| 2915 | int ret = 0; |
| 2916 | |
| 2917 | BUG_ON(!buffer_locked(bh)); |
| 2918 | BUG_ON(!buffer_mapped(bh)); |
| 2919 | BUG_ON(!bh->b_end_io); |
Aneesh Kumar K.V | 8fb0e34 | 2009-05-12 16:22:37 -0400 | [diff] [blame] | 2920 | BUG_ON(buffer_delay(bh)); |
| 2921 | BUG_ON(buffer_unwritten(bh)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2922 | |
Jens Axboe | 48fd4f9 | 2008-08-22 10:00:36 +0200 | [diff] [blame] | 2923 | /* |
Jens Axboe | 48fd4f9 | 2008-08-22 10:00:36 +0200 | [diff] [blame] | 2924 | * Only clear out a write error when rewriting |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2925 | */ |
Jens Axboe | 48fd4f9 | 2008-08-22 10:00:36 +0200 | [diff] [blame] | 2926 | if (test_set_buffer_req(bh) && (rw & WRITE)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2927 | clear_buffer_write_io_error(bh); |
| 2928 | |
| 2929 | /* |
| 2930 | * from here on down, it's all bio -- do the initial mapping, |
| 2931 | * submit_bio -> generic_make_request may further map this bio around |
| 2932 | */ |
| 2933 | bio = bio_alloc(GFP_NOIO, 1); |
| 2934 | |
| 2935 | bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9); |
| 2936 | bio->bi_bdev = bh->b_bdev; |
| 2937 | bio->bi_io_vec[0].bv_page = bh->b_page; |
| 2938 | bio->bi_io_vec[0].bv_len = bh->b_size; |
| 2939 | bio->bi_io_vec[0].bv_offset = bh_offset(bh); |
| 2940 | |
| 2941 | bio->bi_vcnt = 1; |
| 2942 | bio->bi_idx = 0; |
| 2943 | bio->bi_size = bh->b_size; |
| 2944 | |
| 2945 | bio->bi_end_io = end_bio_bh_io_sync; |
| 2946 | bio->bi_private = bh; |
| 2947 | |
| 2948 | bio_get(bio); |
| 2949 | submit_bio(rw, bio); |
| 2950 | |
| 2951 | if (bio_flagged(bio, BIO_EOPNOTSUPP)) |
| 2952 | ret = -EOPNOTSUPP; |
| 2953 | |
| 2954 | bio_put(bio); |
| 2955 | return ret; |
| 2956 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2957 | EXPORT_SYMBOL(submit_bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2958 | |
| 2959 | /** |
| 2960 | * ll_rw_block: low-level access to block devices (DEPRECATED) |
Christoph Hellwig | 9cb569d | 2010-08-11 17:06:24 +0200 | [diff] [blame] | 2961 | * @rw: whether to %READ or %WRITE or maybe %READA (readahead) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2962 | * @nr: number of &struct buffer_heads in the array |
| 2963 | * @bhs: array of pointers to &struct buffer_head |
| 2964 | * |
Jan Kara | a766223 | 2005-09-06 15:19:10 -0700 | [diff] [blame] | 2965 | * ll_rw_block() takes an array of pointers to &struct buffer_heads, and |
| 2966 | * requests an I/O operation on them, either a %READ or a %WRITE. The third |
Christoph Hellwig | 9cb569d | 2010-08-11 17:06:24 +0200 | [diff] [blame] | 2967 | * %READA option is described in the documentation for generic_make_request() |
| 2968 | * which ll_rw_block() calls. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2969 | * |
| 2970 | * This function drops any buffer that it cannot get a lock on (with the |
Christoph Hellwig | 9cb569d | 2010-08-11 17:06:24 +0200 | [diff] [blame] | 2971 | * BH_Lock state bit), any buffer that appears to be clean when doing a write |
| 2972 | * request, and any buffer that appears to be up-to-date when doing read |
| 2973 | * request. Further it marks as clean buffers that are processed for |
| 2974 | * writing (the buffer cache won't assume that they are actually clean |
| 2975 | * until the buffer gets unlocked). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2976 | * |
| 2977 | * ll_rw_block sets b_end_io to simple completion handler that marks |
| 2978 | * the buffer up-to-date (if approriate), unlocks the buffer and wakes |
| 2979 | * any waiters. |
| 2980 | * |
| 2981 | * All of the buffers must be for the same device, and must also be a |
| 2982 | * multiple of the current approved size for the device. |
| 2983 | */ |
| 2984 | void ll_rw_block(int rw, int nr, struct buffer_head *bhs[]) |
| 2985 | { |
| 2986 | int i; |
| 2987 | |
| 2988 | for (i = 0; i < nr; i++) { |
| 2989 | struct buffer_head *bh = bhs[i]; |
| 2990 | |
Christoph Hellwig | 9cb569d | 2010-08-11 17:06:24 +0200 | [diff] [blame] | 2991 | if (!trylock_buffer(bh)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2992 | continue; |
Christoph Hellwig | 9cb569d | 2010-08-11 17:06:24 +0200 | [diff] [blame] | 2993 | if (rw == WRITE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2994 | if (test_clear_buffer_dirty(bh)) { |
akpm@osdl.org | 76c3073 | 2005-04-16 15:24:07 -0700 | [diff] [blame] | 2995 | bh->b_end_io = end_buffer_write_sync; |
OGAWA Hirofumi | e60e5c5 | 2006-02-03 03:04:43 -0800 | [diff] [blame] | 2996 | get_bh(bh); |
Christoph Hellwig | 9cb569d | 2010-08-11 17:06:24 +0200 | [diff] [blame] | 2997 | submit_bh(WRITE, bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2998 | continue; |
| 2999 | } |
| 3000 | } else { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3001 | if (!buffer_uptodate(bh)) { |
akpm@osdl.org | 76c3073 | 2005-04-16 15:24:07 -0700 | [diff] [blame] | 3002 | bh->b_end_io = end_buffer_read_sync; |
OGAWA Hirofumi | e60e5c5 | 2006-02-03 03:04:43 -0800 | [diff] [blame] | 3003 | get_bh(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3004 | submit_bh(rw, bh); |
| 3005 | continue; |
| 3006 | } |
| 3007 | } |
| 3008 | unlock_buffer(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3009 | } |
| 3010 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 3011 | EXPORT_SYMBOL(ll_rw_block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3012 | |
Christoph Hellwig | 9cb569d | 2010-08-11 17:06:24 +0200 | [diff] [blame] | 3013 | void write_dirty_buffer(struct buffer_head *bh, int rw) |
| 3014 | { |
| 3015 | lock_buffer(bh); |
| 3016 | if (!test_clear_buffer_dirty(bh)) { |
| 3017 | unlock_buffer(bh); |
| 3018 | return; |
| 3019 | } |
| 3020 | bh->b_end_io = end_buffer_write_sync; |
| 3021 | get_bh(bh); |
| 3022 | submit_bh(rw, bh); |
| 3023 | } |
| 3024 | EXPORT_SYMBOL(write_dirty_buffer); |
| 3025 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3026 | /* |
| 3027 | * For a data-integrity writeout, we need to wait upon any in-progress I/O |
| 3028 | * and then start new I/O and then wait upon it. The caller must have a ref on |
| 3029 | * the buffer_head. |
| 3030 | */ |
Christoph Hellwig | 87e9951 | 2010-08-11 17:05:45 +0200 | [diff] [blame] | 3031 | int __sync_dirty_buffer(struct buffer_head *bh, int rw) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3032 | { |
| 3033 | int ret = 0; |
| 3034 | |
| 3035 | WARN_ON(atomic_read(&bh->b_count) < 1); |
| 3036 | lock_buffer(bh); |
| 3037 | if (test_clear_buffer_dirty(bh)) { |
| 3038 | get_bh(bh); |
| 3039 | bh->b_end_io = end_buffer_write_sync; |
Christoph Hellwig | 87e9951 | 2010-08-11 17:05:45 +0200 | [diff] [blame] | 3040 | ret = submit_bh(rw, bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3041 | wait_on_buffer(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3042 | if (!ret && !buffer_uptodate(bh)) |
| 3043 | ret = -EIO; |
| 3044 | } else { |
| 3045 | unlock_buffer(bh); |
| 3046 | } |
| 3047 | return ret; |
| 3048 | } |
Christoph Hellwig | 87e9951 | 2010-08-11 17:05:45 +0200 | [diff] [blame] | 3049 | EXPORT_SYMBOL(__sync_dirty_buffer); |
| 3050 | |
| 3051 | int sync_dirty_buffer(struct buffer_head *bh) |
| 3052 | { |
| 3053 | return __sync_dirty_buffer(bh, WRITE_SYNC); |
| 3054 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 3055 | EXPORT_SYMBOL(sync_dirty_buffer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3056 | |
| 3057 | /* |
| 3058 | * try_to_free_buffers() checks if all the buffers on this particular page |
| 3059 | * are unused, and releases them if so. |
| 3060 | * |
| 3061 | * Exclusion against try_to_free_buffers may be obtained by either |
| 3062 | * locking the page or by holding its mapping's private_lock. |
| 3063 | * |
| 3064 | * If the page is dirty but all the buffers are clean then we need to |
| 3065 | * be sure to mark the page clean as well. This is because the page |
| 3066 | * may be against a block device, and a later reattachment of buffers |
| 3067 | * to a dirty page will set *all* buffers dirty. Which would corrupt |
| 3068 | * filesystem data on the same device. |
| 3069 | * |
| 3070 | * The same applies to regular filesystem pages: if all the buffers are |
| 3071 | * clean then we set the page clean and proceed. To do that, we require |
| 3072 | * total exclusion from __set_page_dirty_buffers(). That is obtained with |
| 3073 | * private_lock. |
| 3074 | * |
| 3075 | * try_to_free_buffers() is non-blocking. |
| 3076 | */ |
| 3077 | static inline int buffer_busy(struct buffer_head *bh) |
| 3078 | { |
| 3079 | return atomic_read(&bh->b_count) | |
| 3080 | (bh->b_state & ((1 << BH_Dirty) | (1 << BH_Lock))); |
| 3081 | } |
| 3082 | |
| 3083 | static int |
| 3084 | drop_buffers(struct page *page, struct buffer_head **buffers_to_free) |
| 3085 | { |
| 3086 | struct buffer_head *head = page_buffers(page); |
| 3087 | struct buffer_head *bh; |
| 3088 | |
| 3089 | bh = head; |
| 3090 | do { |
akpm@osdl.org | de7d5a3 | 2005-05-01 08:58:39 -0700 | [diff] [blame] | 3091 | if (buffer_write_io_error(bh) && page->mapping) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3092 | set_bit(AS_EIO, &page->mapping->flags); |
| 3093 | if (buffer_busy(bh)) |
| 3094 | goto failed; |
| 3095 | bh = bh->b_this_page; |
| 3096 | } while (bh != head); |
| 3097 | |
| 3098 | do { |
| 3099 | struct buffer_head *next = bh->b_this_page; |
| 3100 | |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 3101 | if (bh->b_assoc_map) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3102 | __remove_assoc_queue(bh); |
| 3103 | bh = next; |
| 3104 | } while (bh != head); |
| 3105 | *buffers_to_free = head; |
| 3106 | __clear_page_buffers(page); |
| 3107 | return 1; |
| 3108 | failed: |
| 3109 | return 0; |
| 3110 | } |
| 3111 | |
| 3112 | int try_to_free_buffers(struct page *page) |
| 3113 | { |
| 3114 | struct address_space * const mapping = page->mapping; |
| 3115 | struct buffer_head *buffers_to_free = NULL; |
| 3116 | int ret = 0; |
| 3117 | |
| 3118 | BUG_ON(!PageLocked(page)); |
Linus Torvalds | ecdfc97 | 2007-01-26 12:47:06 -0800 | [diff] [blame] | 3119 | if (PageWriteback(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3120 | return 0; |
| 3121 | |
| 3122 | if (mapping == NULL) { /* can this still happen? */ |
| 3123 | ret = drop_buffers(page, &buffers_to_free); |
| 3124 | goto out; |
| 3125 | } |
| 3126 | |
| 3127 | spin_lock(&mapping->private_lock); |
| 3128 | ret = drop_buffers(page, &buffers_to_free); |
Linus Torvalds | ecdfc97 | 2007-01-26 12:47:06 -0800 | [diff] [blame] | 3129 | |
| 3130 | /* |
| 3131 | * If the filesystem writes its buffers by hand (eg ext3) |
| 3132 | * then we can have clean buffers against a dirty page. We |
| 3133 | * clean the page here; otherwise the VM will never notice |
| 3134 | * that the filesystem did any IO at all. |
| 3135 | * |
| 3136 | * Also, during truncate, discard_buffer will have marked all |
| 3137 | * the page's buffers clean. We discover that here and clean |
| 3138 | * the page also. |
Nick Piggin | 87df724 | 2007-01-30 14:36:27 +1100 | [diff] [blame] | 3139 | * |
| 3140 | * private_lock must be held over this entire operation in order |
| 3141 | * to synchronise against __set_page_dirty_buffers and prevent the |
| 3142 | * dirty bit from being lost. |
Linus Torvalds | ecdfc97 | 2007-01-26 12:47:06 -0800 | [diff] [blame] | 3143 | */ |
| 3144 | if (ret) |
| 3145 | cancel_dirty_page(page, PAGE_CACHE_SIZE); |
Nick Piggin | 87df724 | 2007-01-30 14:36:27 +1100 | [diff] [blame] | 3146 | spin_unlock(&mapping->private_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3147 | out: |
| 3148 | if (buffers_to_free) { |
| 3149 | struct buffer_head *bh = buffers_to_free; |
| 3150 | |
| 3151 | do { |
| 3152 | struct buffer_head *next = bh->b_this_page; |
| 3153 | free_buffer_head(bh); |
| 3154 | bh = next; |
| 3155 | } while (bh != buffers_to_free); |
| 3156 | } |
| 3157 | return ret; |
| 3158 | } |
| 3159 | EXPORT_SYMBOL(try_to_free_buffers); |
| 3160 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3161 | /* |
| 3162 | * There are no bdflush tunables left. But distributions are |
| 3163 | * still running obsolete flush daemons, so we terminate them here. |
| 3164 | * |
| 3165 | * Use of bdflush() is deprecated and will be removed in a future kernel. |
Jens Axboe | 5b0830c | 2009-09-23 19:37:09 +0200 | [diff] [blame] | 3166 | * The `flush-X' kernel threads fully replace bdflush daemons and this call. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3167 | */ |
Heiko Carstens | bdc480e | 2009-01-14 14:14:12 +0100 | [diff] [blame] | 3168 | SYSCALL_DEFINE2(bdflush, int, func, long, data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3169 | { |
| 3170 | static int msg_count; |
| 3171 | |
| 3172 | if (!capable(CAP_SYS_ADMIN)) |
| 3173 | return -EPERM; |
| 3174 | |
| 3175 | if (msg_count < 5) { |
| 3176 | msg_count++; |
| 3177 | printk(KERN_INFO |
| 3178 | "warning: process `%s' used the obsolete bdflush" |
| 3179 | " system call\n", current->comm); |
| 3180 | printk(KERN_INFO "Fix your initscripts?\n"); |
| 3181 | } |
| 3182 | |
| 3183 | if (func == 1) |
| 3184 | do_exit(0); |
| 3185 | return 0; |
| 3186 | } |
| 3187 | |
| 3188 | /* |
| 3189 | * Buffer-head allocation |
| 3190 | */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 3191 | static struct kmem_cache *bh_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3192 | |
| 3193 | /* |
| 3194 | * Once the number of bh's in the machine exceeds this level, we start |
| 3195 | * stripping them in writeback. |
| 3196 | */ |
| 3197 | static int max_buffer_heads; |
| 3198 | |
| 3199 | int buffer_heads_over_limit; |
| 3200 | |
| 3201 | struct bh_accounting { |
| 3202 | int nr; /* Number of live bh's */ |
| 3203 | int ratelimit; /* Limit cacheline bouncing */ |
| 3204 | }; |
| 3205 | |
| 3206 | static DEFINE_PER_CPU(struct bh_accounting, bh_accounting) = {0, 0}; |
| 3207 | |
| 3208 | static void recalc_bh_state(void) |
| 3209 | { |
| 3210 | int i; |
| 3211 | int tot = 0; |
| 3212 | |
Christoph Lameter | ee1be86 | 2010-12-06 11:40:05 -0600 | [diff] [blame] | 3213 | if (__this_cpu_inc_return(bh_accounting.ratelimit) - 1 < 4096) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3214 | return; |
Christoph Lameter | c7b9251 | 2010-12-06 11:16:28 -0600 | [diff] [blame] | 3215 | __this_cpu_write(bh_accounting.ratelimit, 0); |
Eric Dumazet | 8a14342 | 2006-03-24 03:18:10 -0800 | [diff] [blame] | 3216 | for_each_online_cpu(i) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3217 | tot += per_cpu(bh_accounting, i).nr; |
| 3218 | buffer_heads_over_limit = (tot > max_buffer_heads); |
| 3219 | } |
Christoph Lameter | c7b9251 | 2010-12-06 11:16:28 -0600 | [diff] [blame] | 3220 | |
Al Viro | dd0fc66 | 2005-10-07 07:46:04 +0100 | [diff] [blame] | 3221 | struct buffer_head *alloc_buffer_head(gfp_t gfp_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3222 | { |
Richard Kennedy | 019b4d1 | 2010-03-10 15:20:33 -0800 | [diff] [blame] | 3223 | struct buffer_head *ret = kmem_cache_zalloc(bh_cachep, gfp_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3224 | if (ret) { |
Christoph Lameter | a35afb8 | 2007-05-16 22:10:57 -0700 | [diff] [blame] | 3225 | INIT_LIST_HEAD(&ret->b_assoc_buffers); |
Christoph Lameter | c7b9251 | 2010-12-06 11:16:28 -0600 | [diff] [blame] | 3226 | preempt_disable(); |
| 3227 | __this_cpu_inc(bh_accounting.nr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3228 | recalc_bh_state(); |
Christoph Lameter | c7b9251 | 2010-12-06 11:16:28 -0600 | [diff] [blame] | 3229 | preempt_enable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3230 | } |
| 3231 | return ret; |
| 3232 | } |
| 3233 | EXPORT_SYMBOL(alloc_buffer_head); |
| 3234 | |
| 3235 | void free_buffer_head(struct buffer_head *bh) |
| 3236 | { |
| 3237 | BUG_ON(!list_empty(&bh->b_assoc_buffers)); |
| 3238 | kmem_cache_free(bh_cachep, bh); |
Christoph Lameter | c7b9251 | 2010-12-06 11:16:28 -0600 | [diff] [blame] | 3239 | preempt_disable(); |
| 3240 | __this_cpu_dec(bh_accounting.nr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3241 | recalc_bh_state(); |
Christoph Lameter | c7b9251 | 2010-12-06 11:16:28 -0600 | [diff] [blame] | 3242 | preempt_enable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3243 | } |
| 3244 | EXPORT_SYMBOL(free_buffer_head); |
| 3245 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3246 | static void buffer_exit_cpu(int cpu) |
| 3247 | { |
| 3248 | int i; |
| 3249 | struct bh_lru *b = &per_cpu(bh_lrus, cpu); |
| 3250 | |
| 3251 | for (i = 0; i < BH_LRU_SIZE; i++) { |
| 3252 | brelse(b->bhs[i]); |
| 3253 | b->bhs[i] = NULL; |
| 3254 | } |
Christoph Lameter | c7b9251 | 2010-12-06 11:16:28 -0600 | [diff] [blame] | 3255 | this_cpu_add(bh_accounting.nr, per_cpu(bh_accounting, cpu).nr); |
Eric Dumazet | 8a14342 | 2006-03-24 03:18:10 -0800 | [diff] [blame] | 3256 | per_cpu(bh_accounting, cpu).nr = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3257 | } |
| 3258 | |
| 3259 | static int buffer_cpu_notify(struct notifier_block *self, |
| 3260 | unsigned long action, void *hcpu) |
| 3261 | { |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 3262 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3263 | buffer_exit_cpu((unsigned long)hcpu); |
| 3264 | return NOTIFY_OK; |
| 3265 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3266 | |
Aneesh Kumar K.V | 389d1b0 | 2008-01-28 23:58:26 -0500 | [diff] [blame] | 3267 | /** |
Randy Dunlap | a6b9191 | 2008-03-19 17:01:00 -0700 | [diff] [blame] | 3268 | * bh_uptodate_or_lock - Test whether the buffer is uptodate |
Aneesh Kumar K.V | 389d1b0 | 2008-01-28 23:58:26 -0500 | [diff] [blame] | 3269 | * @bh: struct buffer_head |
| 3270 | * |
| 3271 | * Return true if the buffer is up-to-date and false, |
| 3272 | * with the buffer locked, if not. |
| 3273 | */ |
| 3274 | int bh_uptodate_or_lock(struct buffer_head *bh) |
| 3275 | { |
| 3276 | if (!buffer_uptodate(bh)) { |
| 3277 | lock_buffer(bh); |
| 3278 | if (!buffer_uptodate(bh)) |
| 3279 | return 0; |
| 3280 | unlock_buffer(bh); |
| 3281 | } |
| 3282 | return 1; |
| 3283 | } |
| 3284 | EXPORT_SYMBOL(bh_uptodate_or_lock); |
| 3285 | |
| 3286 | /** |
Randy Dunlap | a6b9191 | 2008-03-19 17:01:00 -0700 | [diff] [blame] | 3287 | * bh_submit_read - Submit a locked buffer for reading |
Aneesh Kumar K.V | 389d1b0 | 2008-01-28 23:58:26 -0500 | [diff] [blame] | 3288 | * @bh: struct buffer_head |
| 3289 | * |
| 3290 | * Returns zero on success and -EIO on error. |
| 3291 | */ |
| 3292 | int bh_submit_read(struct buffer_head *bh) |
| 3293 | { |
| 3294 | BUG_ON(!buffer_locked(bh)); |
| 3295 | |
| 3296 | if (buffer_uptodate(bh)) { |
| 3297 | unlock_buffer(bh); |
| 3298 | return 0; |
| 3299 | } |
| 3300 | |
| 3301 | get_bh(bh); |
| 3302 | bh->b_end_io = end_buffer_read_sync; |
| 3303 | submit_bh(READ, bh); |
| 3304 | wait_on_buffer(bh); |
| 3305 | if (buffer_uptodate(bh)) |
| 3306 | return 0; |
| 3307 | return -EIO; |
| 3308 | } |
| 3309 | EXPORT_SYMBOL(bh_submit_read); |
| 3310 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3311 | void __init buffer_init(void) |
| 3312 | { |
| 3313 | int nrpages; |
| 3314 | |
Christoph Lameter | b98938c | 2008-02-04 22:28:36 -0800 | [diff] [blame] | 3315 | bh_cachep = kmem_cache_create("buffer_head", |
| 3316 | sizeof(struct buffer_head), 0, |
| 3317 | (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| |
| 3318 | SLAB_MEM_SPREAD), |
Richard Kennedy | 019b4d1 | 2010-03-10 15:20:33 -0800 | [diff] [blame] | 3319 | NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3320 | |
| 3321 | /* |
| 3322 | * Limit the bh occupancy to 10% of ZONE_NORMAL |
| 3323 | */ |
| 3324 | nrpages = (nr_free_buffer_pages() * 10) / 100; |
| 3325 | max_buffer_heads = nrpages * (PAGE_SIZE / sizeof(struct buffer_head)); |
| 3326 | hotcpu_notifier(buffer_cpu_notify, 0); |
| 3327 | } |