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