blob: 95f786ec7f088f1c85b7e82dfd01fe9bb7246fe3 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/block_dev.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
6 */
7
Linus Torvalds1da177e2005-04-16 15:20:36 -07008#include <linux/init.h>
9#include <linux/mm.h>
10#include <linux/fcntl.h>
11#include <linux/slab.h>
12#include <linux/kmod.h>
13#include <linux/major.h>
Pavel Emelyanov7db9cfd2008-06-05 22:46:27 -070014#include <linux/device_cgroup.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/highmem.h>
16#include <linux/blkdev.h>
17#include <linux/module.h>
18#include <linux/blkpg.h>
19#include <linux/buffer_head.h>
Nick Piggin585d3bc2009-02-25 10:44:19 +010020#include <linux/pagevec.h>
David Howells811d7362006-08-29 19:06:09 +010021#include <linux/writeback.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/mpage.h>
23#include <linux/mount.h>
24#include <linux/uio.h>
25#include <linux/namei.h>
Vignesh Babu BM1368c4f2007-05-08 00:24:32 -070026#include <linux/log2.h>
Catalin Marinas2e1483c2009-06-11 13:24:13 +010027#include <linux/kmemleak.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <asm/uaccess.h>
David Howells07f3f052006-09-30 20:52:18 +020029#include "internal.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
31struct bdev_inode {
32 struct block_device bdev;
33 struct inode vfs_inode;
34};
35
Adrian Bunk4c54ac62008-02-18 13:48:31 +010036static const struct address_space_operations def_blk_aops;
37
Linus Torvalds1da177e2005-04-16 15:20:36 -070038static inline struct bdev_inode *BDEV_I(struct inode *inode)
39{
40 return container_of(inode, struct bdev_inode, vfs_inode);
41}
42
43inline struct block_device *I_BDEV(struct inode *inode)
44{
45 return &BDEV_I(inode)->bdev;
46}
Linus Torvalds1da177e2005-04-16 15:20:36 -070047EXPORT_SYMBOL(I_BDEV);
48
Dave Chinnera5491e02010-10-21 11:49:26 +110049/*
Christoph Hellwigf758eea2011-04-21 18:19:44 -060050 * Move the inode from its current bdi to a new bdi. If the inode is dirty we
51 * need to move it onto the dirty list of @dst so that the inode is always on
52 * the right list.
Dave Chinnera5491e02010-10-21 11:49:26 +110053 */
54static void bdev_inode_switch_bdi(struct inode *inode,
55 struct backing_dev_info *dst)
56{
Christoph Hellwigf758eea2011-04-21 18:19:44 -060057 struct backing_dev_info *old = inode->i_data.backing_dev_info;
58
59 if (unlikely(dst == old)) /* deadlock avoidance */
60 return;
61 bdi_lock_two(&old->wb, &dst->wb);
Dave Chinner250df6e2011-03-22 22:23:36 +110062 spin_lock(&inode->i_lock);
Dave Chinnera5491e02010-10-21 11:49:26 +110063 inode->i_data.backing_dev_info = dst;
64 if (inode->i_state & I_DIRTY)
Nick Piggin7ccf19a2010-10-21 11:49:30 +110065 list_move(&inode->i_wb_list, &dst->wb.b_dirty);
Dave Chinner250df6e2011-03-22 22:23:36 +110066 spin_unlock(&inode->i_lock);
Christoph Hellwigf758eea2011-04-21 18:19:44 -060067 spin_unlock(&old->wb.list_lock);
68 spin_unlock(&dst->wb.list_lock);
Dave Chinnera5491e02010-10-21 11:49:26 +110069}
70
Linus Torvalds1da177e2005-04-16 15:20:36 -070071static sector_t max_block(struct block_device *bdev)
72{
73 sector_t retval = ~((sector_t)0);
74 loff_t sz = i_size_read(bdev->bd_inode);
75
76 if (sz) {
77 unsigned int size = block_size(bdev);
78 unsigned int sizebits = blksize_bits(size);
79 retval = (sz >> sizebits);
80 }
81 return retval;
82}
83
Peter Zijlstraf9a14392007-05-06 14:49:55 -070084/* Kill _all_ buffers and pagecache , dirty or not.. */
Linus Torvalds1da177e2005-04-16 15:20:36 -070085static void kill_bdev(struct block_device *bdev)
86{
Peter Zijlstraf9a14392007-05-06 14:49:55 -070087 if (bdev->bd_inode->i_mapping->nrpages == 0)
88 return;
89 invalidate_bh_lrus();
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 truncate_inode_pages(bdev->bd_inode->i_mapping, 0);
91}
92
93int set_blocksize(struct block_device *bdev, int size)
94{
95 /* Size must be a power of two, and between 512 and PAGE_SIZE */
Vignesh Babu BM1368c4f2007-05-08 00:24:32 -070096 if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 return -EINVAL;
98
99 /* Size cannot be smaller than the size supported by the device */
Martin K. Petersene1defc42009-05-22 17:17:49 -0400100 if (size < bdev_logical_block_size(bdev))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 return -EINVAL;
102
103 /* Don't change the size if it is same as current */
104 if (bdev->bd_block_size != size) {
105 sync_blockdev(bdev);
106 bdev->bd_block_size = size;
107 bdev->bd_inode->i_blkbits = blksize_bits(size);
108 kill_bdev(bdev);
109 }
110 return 0;
111}
112
113EXPORT_SYMBOL(set_blocksize);
114
115int sb_set_blocksize(struct super_block *sb, int size)
116{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 if (set_blocksize(sb->s_bdev, size))
118 return 0;
119 /* If we get here, we know size is power of two
120 * and it's value is between 512 and PAGE_SIZE */
121 sb->s_blocksize = size;
Coywolf Qi Hunt38885bd2006-03-24 03:18:05 -0800122 sb->s_blocksize_bits = blksize_bits(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 return sb->s_blocksize;
124}
125
126EXPORT_SYMBOL(sb_set_blocksize);
127
128int sb_min_blocksize(struct super_block *sb, int size)
129{
Martin K. Petersene1defc42009-05-22 17:17:49 -0400130 int minsize = bdev_logical_block_size(sb->s_bdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 if (size < minsize)
132 size = minsize;
133 return sb_set_blocksize(sb, size);
134}
135
136EXPORT_SYMBOL(sb_min_blocksize);
137
138static int
139blkdev_get_block(struct inode *inode, sector_t iblock,
140 struct buffer_head *bh, int create)
141{
142 if (iblock >= max_block(I_BDEV(inode))) {
143 if (create)
144 return -EIO;
145
146 /*
147 * for reads, we're just trying to fill a partial page.
148 * return a hole, they will have to call get_block again
149 * before they can fill it, and they will get -EIO at that
150 * time
151 */
152 return 0;
153 }
154 bh->b_bdev = I_BDEV(inode);
155 bh->b_blocknr = iblock;
156 set_buffer_mapped(bh);
157 return 0;
158}
159
Andrew Mortonb2e895d2007-02-03 01:14:01 -0800160static int
161blkdev_get_blocks(struct inode *inode, sector_t iblock,
162 struct buffer_head *bh, int create)
163{
164 sector_t end_block = max_block(I_BDEV(inode));
165 unsigned long max_blocks = bh->b_size >> inode->i_blkbits;
166
167 if ((iblock + max_blocks) > end_block) {
168 max_blocks = end_block - iblock;
169 if ((long)max_blocks <= 0) {
170 if (create)
171 return -EIO; /* write fully beyond EOF */
172 /*
173 * It is a read which is fully beyond EOF. We return
174 * a !buffer_mapped buffer
175 */
176 max_blocks = 0;
177 }
178 }
179
180 bh->b_bdev = I_BDEV(inode);
181 bh->b_blocknr = iblock;
182 bh->b_size = max_blocks << inode->i_blkbits;
183 if (max_blocks)
184 set_buffer_mapped(bh);
185 return 0;
186}
187
188static ssize_t
189blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
190 loff_t offset, unsigned long nr_segs)
191{
192 struct file *file = iocb->ki_filp;
193 struct inode *inode = file->f_mapping->host;
194
Christoph Hellwigeafdc7d2010-06-04 11:29:53 +0200195 return __blockdev_direct_IO(rw, iocb, inode, I_BDEV(inode), iov, offset,
196 nr_segs, blkdev_get_blocks, NULL, NULL, 0);
Andrew Mortonb2e895d2007-02-03 01:14:01 -0800197}
198
Jan Kara5cee5812009-04-27 16:43:51 +0200199int __sync_blockdev(struct block_device *bdev, int wait)
200{
201 if (!bdev)
202 return 0;
203 if (!wait)
204 return filemap_flush(bdev->bd_inode->i_mapping);
205 return filemap_write_and_wait(bdev->bd_inode->i_mapping);
206}
207
Nick Piggin585d3bc2009-02-25 10:44:19 +0100208/*
209 * Write out and wait upon all the dirty data associated with a block
210 * device via its mapping. Does not take the superblock lock.
211 */
212int sync_blockdev(struct block_device *bdev)
213{
Jan Kara5cee5812009-04-27 16:43:51 +0200214 return __sync_blockdev(bdev, 1);
Nick Piggin585d3bc2009-02-25 10:44:19 +0100215}
216EXPORT_SYMBOL(sync_blockdev);
217
218/*
219 * Write out and wait upon all dirty data associated with this
220 * device. Filesystem data as well as the underlying block
221 * device. Takes the superblock lock.
222 */
223int fsync_bdev(struct block_device *bdev)
224{
225 struct super_block *sb = get_super(bdev);
226 if (sb) {
Jan Kara60b06802009-04-27 16:43:53 +0200227 int res = sync_filesystem(sb);
Nick Piggin585d3bc2009-02-25 10:44:19 +0100228 drop_super(sb);
229 return res;
230 }
231 return sync_blockdev(bdev);
232}
Al Viro47e44912009-04-01 07:07:16 -0400233EXPORT_SYMBOL(fsync_bdev);
Nick Piggin585d3bc2009-02-25 10:44:19 +0100234
235/**
236 * freeze_bdev -- lock a filesystem and force it into a consistent state
237 * @bdev: blockdevice to lock
238 *
Nick Piggin585d3bc2009-02-25 10:44:19 +0100239 * If a superblock is found on this device, we take the s_umount semaphore
240 * on it to make sure nobody unmounts until the snapshot creation is done.
241 * The reference counter (bd_fsfreeze_count) guarantees that only the last
242 * unfreeze process can unfreeze the frozen filesystem actually when multiple
243 * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
244 * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
245 * actually.
246 */
247struct super_block *freeze_bdev(struct block_device *bdev)
248{
249 struct super_block *sb;
250 int error = 0;
251
252 mutex_lock(&bdev->bd_fsfreeze_mutex);
Christoph Hellwig45042302009-08-03 23:28:35 +0200253 if (++bdev->bd_fsfreeze_count > 1) {
254 /*
255 * We don't even need to grab a reference - the first call
256 * to freeze_bdev grab an active reference and only the last
257 * thaw_bdev drops it.
258 */
Nick Piggin585d3bc2009-02-25 10:44:19 +0100259 sb = get_super(bdev);
Christoph Hellwig45042302009-08-03 23:28:35 +0200260 drop_super(sb);
Nick Piggin585d3bc2009-02-25 10:44:19 +0100261 mutex_unlock(&bdev->bd_fsfreeze_mutex);
262 return sb;
263 }
Nick Piggin585d3bc2009-02-25 10:44:19 +0100264
Christoph Hellwig45042302009-08-03 23:28:35 +0200265 sb = get_active_super(bdev);
266 if (!sb)
267 goto out;
Josef Bacik18e9e512010-03-23 10:34:56 -0400268 error = freeze_super(sb);
269 if (error) {
270 deactivate_super(sb);
271 bdev->bd_fsfreeze_count--;
Christoph Hellwig45042302009-08-03 23:28:35 +0200272 mutex_unlock(&bdev->bd_fsfreeze_mutex);
Josef Bacik18e9e512010-03-23 10:34:56 -0400273 return ERR_PTR(error);
Nick Piggin585d3bc2009-02-25 10:44:19 +0100274 }
Josef Bacik18e9e512010-03-23 10:34:56 -0400275 deactivate_super(sb);
Christoph Hellwig45042302009-08-03 23:28:35 +0200276 out:
Nick Piggin585d3bc2009-02-25 10:44:19 +0100277 sync_blockdev(bdev);
278 mutex_unlock(&bdev->bd_fsfreeze_mutex);
Christoph Hellwig4fadd7b2009-08-03 23:28:06 +0200279 return sb; /* thaw_bdev releases s->s_umount */
Nick Piggin585d3bc2009-02-25 10:44:19 +0100280}
281EXPORT_SYMBOL(freeze_bdev);
282
283/**
284 * thaw_bdev -- unlock filesystem
285 * @bdev: blockdevice to unlock
286 * @sb: associated superblock
287 *
288 * Unlocks the filesystem and marks it writeable again after freeze_bdev().
289 */
290int thaw_bdev(struct block_device *bdev, struct super_block *sb)
291{
Christoph Hellwig45042302009-08-03 23:28:35 +0200292 int error = -EINVAL;
Nick Piggin585d3bc2009-02-25 10:44:19 +0100293
294 mutex_lock(&bdev->bd_fsfreeze_mutex);
Christoph Hellwig45042302009-08-03 23:28:35 +0200295 if (!bdev->bd_fsfreeze_count)
Josef Bacik18e9e512010-03-23 10:34:56 -0400296 goto out;
Nick Piggin585d3bc2009-02-25 10:44:19 +0100297
Christoph Hellwig45042302009-08-03 23:28:35 +0200298 error = 0;
299 if (--bdev->bd_fsfreeze_count > 0)
Josef Bacik18e9e512010-03-23 10:34:56 -0400300 goto out;
Nick Piggin585d3bc2009-02-25 10:44:19 +0100301
Christoph Hellwig45042302009-08-03 23:28:35 +0200302 if (!sb)
Josef Bacik18e9e512010-03-23 10:34:56 -0400303 goto out;
Christoph Hellwig45042302009-08-03 23:28:35 +0200304
Josef Bacik18e9e512010-03-23 10:34:56 -0400305 error = thaw_super(sb);
306 if (error) {
307 bdev->bd_fsfreeze_count++;
308 mutex_unlock(&bdev->bd_fsfreeze_mutex);
309 return error;
Nick Piggin585d3bc2009-02-25 10:44:19 +0100310 }
Josef Bacik18e9e512010-03-23 10:34:56 -0400311out:
Nick Piggin585d3bc2009-02-25 10:44:19 +0100312 mutex_unlock(&bdev->bd_fsfreeze_mutex);
313 return 0;
314}
315EXPORT_SYMBOL(thaw_bdev);
316
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
318{
319 return block_write_full_page(page, blkdev_get_block, wbc);
320}
321
322static int blkdev_readpage(struct file * file, struct page * page)
323{
324 return block_read_full_page(page, blkdev_get_block);
325}
326
Nick Piggin6272b5a2007-10-16 01:25:04 -0700327static int blkdev_write_begin(struct file *file, struct address_space *mapping,
328 loff_t pos, unsigned len, unsigned flags,
329 struct page **pagep, void **fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330{
Christoph Hellwig155130a2010-06-04 11:29:58 +0200331 return block_write_begin(mapping, pos, len, flags, pagep,
332 blkdev_get_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333}
334
Nick Piggin6272b5a2007-10-16 01:25:04 -0700335static int blkdev_write_end(struct file *file, struct address_space *mapping,
336 loff_t pos, unsigned len, unsigned copied,
337 struct page *page, void *fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338{
Nick Piggin6272b5a2007-10-16 01:25:04 -0700339 int ret;
340 ret = block_write_end(file, mapping, pos, len, copied, page, fsdata);
341
342 unlock_page(page);
343 page_cache_release(page);
344
345 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346}
347
348/*
349 * private llseek:
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800350 * for a block special file file->f_path.dentry->d_inode->i_size is zero
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 * so we compute the size by hand (just as in block_read/write above)
352 */
353static loff_t block_llseek(struct file *file, loff_t offset, int origin)
354{
355 struct inode *bd_inode = file->f_mapping->host;
356 loff_t size;
357 loff_t retval;
358
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800359 mutex_lock(&bd_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 size = i_size_read(bd_inode);
361
Josef Bacik06222e42011-07-18 13:21:38 -0400362 retval = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 switch (origin) {
Josef Bacik06222e42011-07-18 13:21:38 -0400364 case SEEK_END:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 offset += size;
366 break;
Josef Bacik06222e42011-07-18 13:21:38 -0400367 case SEEK_CUR:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 offset += file->f_pos;
Josef Bacik06222e42011-07-18 13:21:38 -0400369 case SEEK_SET:
370 break;
371 default:
372 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 if (offset >= 0 && offset <= size) {
375 if (offset != file->f_pos) {
376 file->f_pos = offset;
377 }
378 retval = offset;
379 }
Josef Bacik06222e42011-07-18 13:21:38 -0400380out:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800381 mutex_unlock(&bd_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 return retval;
383}
384
Josef Bacik02c24a82011-07-16 20:44:56 -0400385int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386{
Anton Blanchardb8af67e2010-04-23 13:18:06 -0400387 struct inode *bd_inode = filp->f_mapping->host;
388 struct block_device *bdev = I_BDEV(bd_inode);
Christoph Hellwigab0a9732009-10-29 14:14:04 +0100389 int error;
Rafael J. Wysockida5aa862011-08-02 02:17:48 +0200390
391 error = filemap_write_and_wait_range(filp->f_mapping, start, end);
392 if (error)
393 return error;
Christoph Hellwigab0a9732009-10-29 14:14:04 +0100394
Anton Blanchardb8af67e2010-04-23 13:18:06 -0400395 /*
396 * There is no need to serialise calls to blkdev_issue_flush with
397 * i_mutex and doing so causes performance issues with concurrent
398 * O_SYNC writers to a block device.
399 */
Christoph Hellwigdd3932e2010-09-16 20:51:46 +0200400 error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL);
Christoph Hellwigab0a9732009-10-29 14:14:04 +0100401 if (error == -EOPNOTSUPP)
402 error = 0;
Anton Blanchardb8af67e2010-04-23 13:18:06 -0400403
Christoph Hellwigab0a9732009-10-29 14:14:04 +0100404 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405}
Andrew Mortonb1dd3b22010-04-06 14:35:00 -0700406EXPORT_SYMBOL(blkdev_fsync);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407
408/*
409 * pseudo-fs
410 */
411
412static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
Christoph Lametere18b8902006-12-06 20:33:20 -0800413static struct kmem_cache * bdev_cachep __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414
415static struct inode *bdev_alloc_inode(struct super_block *sb)
416{
Christoph Lametere94b1762006-12-06 20:33:17 -0800417 struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 if (!ei)
419 return NULL;
420 return &ei->vfs_inode;
421}
422
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +1100423static void bdev_i_callback(struct rcu_head *head)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424{
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +1100425 struct inode *inode = container_of(head, struct inode, i_rcu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 struct bdev_inode *bdi = BDEV_I(inode);
427
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +1100428 INIT_LIST_HEAD(&inode->i_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429 kmem_cache_free(bdev_cachep, bdi);
430}
431
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +1100432static void bdev_destroy_inode(struct inode *inode)
433{
434 call_rcu(&inode->i_rcu, bdev_i_callback);
435}
436
Alexey Dobriyan51cc5062008-07-25 19:45:34 -0700437static void init_once(void *foo)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438{
439 struct bdev_inode *ei = (struct bdev_inode *) foo;
440 struct block_device *bdev = &ei->bdev;
441
Christoph Lametera35afb82007-05-16 22:10:57 -0700442 memset(bdev, 0, sizeof(*bdev));
443 mutex_init(&bdev->bd_mutex);
Christoph Lametera35afb82007-05-16 22:10:57 -0700444 INIT_LIST_HEAD(&bdev->bd_inodes);
445 INIT_LIST_HEAD(&bdev->bd_list);
Tejun Heo49731ba2011-01-14 18:43:57 +0100446#ifdef CONFIG_SYSFS
447 INIT_LIST_HEAD(&bdev->bd_holder_disks);
448#endif
Christoph Lametera35afb82007-05-16 22:10:57 -0700449 inode_init_once(&ei->vfs_inode);
Takashi Satofcccf502009-01-09 16:40:59 -0800450 /* Initialize mutex for freeze. */
451 mutex_init(&bdev->bd_fsfreeze_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452}
453
454static inline void __bd_forget(struct inode *inode)
455{
456 list_del_init(&inode->i_devices);
457 inode->i_bdev = NULL;
458 inode->i_mapping = &inode->i_data;
459}
460
Al Virob57922d2010-06-07 14:34:48 -0400461static void bdev_evict_inode(struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462{
463 struct block_device *bdev = &BDEV_I(inode)->bdev;
464 struct list_head *p;
Al Virob57922d2010-06-07 14:34:48 -0400465 truncate_inode_pages(&inode->i_data, 0);
466 invalidate_inode_buffers(inode); /* is it needed here? */
467 end_writeback(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 spin_lock(&bdev_lock);
469 while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) {
470 __bd_forget(list_entry(p, struct inode, i_devices));
471 }
472 list_del_init(&bdev->bd_list);
473 spin_unlock(&bdev_lock);
474}
475
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800476static const struct super_operations bdev_sops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 .statfs = simple_statfs,
478 .alloc_inode = bdev_alloc_inode,
479 .destroy_inode = bdev_destroy_inode,
480 .drop_inode = generic_delete_inode,
Al Virob57922d2010-06-07 14:34:48 -0400481 .evict_inode = bdev_evict_inode,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482};
483
Al Viro51139ad2010-07-25 23:47:46 +0400484static struct dentry *bd_mount(struct file_system_type *fs_type,
485 int flags, const char *dev_name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486{
Al Viroc74a1cb2011-01-12 16:59:34 -0500487 return mount_pseudo(fs_type, "bdev:", &bdev_sops, NULL, 0x62646576);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488}
489
490static struct file_system_type bd_type = {
491 .name = "bdev",
Al Viro51139ad2010-07-25 23:47:46 +0400492 .mount = bd_mount,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493 .kill_sb = kill_anon_super,
494};
495
Denis ChengRqc2acf7b2008-12-01 14:34:56 -0800496struct super_block *blockdev_superblock __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497
498void __init bdev_cache_init(void)
499{
500 int err;
Denis ChengRqc2acf7b2008-12-01 14:34:56 -0800501 struct vfsmount *bd_mnt;
502
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
Paul Jacksonfffb60f2006-03-24 03:16:06 -0800504 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
505 SLAB_MEM_SPREAD|SLAB_PANIC),
Paul Mundt20c2df82007-07-20 10:11:58 +0900506 init_once);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 err = register_filesystem(&bd_type);
508 if (err)
509 panic("Cannot register bdev pseudo-fs");
510 bd_mnt = kern_mount(&bd_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 if (IS_ERR(bd_mnt))
512 panic("Cannot create bdev pseudo-fs");
Catalin Marinas2e1483c2009-06-11 13:24:13 +0100513 /*
514 * This vfsmount structure is only used to obtain the
515 * blockdev_superblock, so tell kmemleak not to report it.
516 */
517 kmemleak_not_leak(bd_mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
519}
520
521/*
522 * Most likely _very_ bad one - but then it's hardly critical for small
523 * /dev and can be fixed when somebody will need really large one.
524 * Keep in mind that it will be fed through icache hash function too.
525 */
526static inline unsigned long hash(dev_t dev)
527{
528 return MAJOR(dev)+MINOR(dev);
529}
530
531static int bdev_test(struct inode *inode, void *data)
532{
533 return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data;
534}
535
536static int bdev_set(struct inode *inode, void *data)
537{
538 BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data;
539 return 0;
540}
541
542static LIST_HEAD(all_bdevs);
543
544struct block_device *bdget(dev_t dev)
545{
546 struct block_device *bdev;
547 struct inode *inode;
548
Denis ChengRqc2acf7b2008-12-01 14:34:56 -0800549 inode = iget5_locked(blockdev_superblock, hash(dev),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 bdev_test, bdev_set, &dev);
551
552 if (!inode)
553 return NULL;
554
555 bdev = &BDEV_I(inode)->bdev;
556
557 if (inode->i_state & I_NEW) {
558 bdev->bd_contains = NULL;
Lachlan McIlroy782b94c2011-06-30 11:01:45 +1000559 bdev->bd_super = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 bdev->bd_inode = inode;
561 bdev->bd_block_size = (1 << inode->i_blkbits);
562 bdev->bd_part_count = 0;
563 bdev->bd_invalidated = 0;
564 inode->i_mode = S_IFBLK;
565 inode->i_rdev = dev;
566 inode->i_bdev = bdev;
567 inode->i_data.a_ops = &def_blk_aops;
568 mapping_set_gfp_mask(&inode->i_data, GFP_USER);
569 inode->i_data.backing_dev_info = &default_backing_dev_info;
570 spin_lock(&bdev_lock);
571 list_add(&bdev->bd_list, &all_bdevs);
572 spin_unlock(&bdev_lock);
573 unlock_new_inode(inode);
574 }
575 return bdev;
576}
577
578EXPORT_SYMBOL(bdget);
579
Alan Jenkinsdddac6a2009-07-29 21:07:55 +0200580/**
581 * bdgrab -- Grab a reference to an already referenced block device
582 * @bdev: Block device to grab a reference to.
583 */
584struct block_device *bdgrab(struct block_device *bdev)
585{
Al Viro7de9c6ee2010-10-23 11:11:40 -0400586 ihold(bdev->bd_inode);
Alan Jenkinsdddac6a2009-07-29 21:07:55 +0200587 return bdev;
588}
589
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590long nr_blockdev_pages(void)
591{
Matthias Kaehlcke203a2932007-07-15 23:40:23 -0700592 struct block_device *bdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 long ret = 0;
594 spin_lock(&bdev_lock);
Matthias Kaehlcke203a2932007-07-15 23:40:23 -0700595 list_for_each_entry(bdev, &all_bdevs, bd_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 ret += bdev->bd_inode->i_mapping->nrpages;
597 }
598 spin_unlock(&bdev_lock);
599 return ret;
600}
601
602void bdput(struct block_device *bdev)
603{
604 iput(bdev->bd_inode);
605}
606
607EXPORT_SYMBOL(bdput);
608
609static struct block_device *bd_acquire(struct inode *inode)
610{
611 struct block_device *bdev;
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700612
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 spin_lock(&bdev_lock);
614 bdev = inode->i_bdev;
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700615 if (bdev) {
Al Viro7de9c6ee2010-10-23 11:11:40 -0400616 ihold(bdev->bd_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 spin_unlock(&bdev_lock);
618 return bdev;
619 }
620 spin_unlock(&bdev_lock);
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700621
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 bdev = bdget(inode->i_rdev);
623 if (bdev) {
624 spin_lock(&bdev_lock);
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700625 if (!inode->i_bdev) {
626 /*
Al Viro7de9c6ee2010-10-23 11:11:40 -0400627 * We take an additional reference to bd_inode,
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700628 * and it's released in clear_inode() of inode.
629 * So, we can access it via ->i_mapping always
630 * without igrab().
631 */
Al Viro7de9c6ee2010-10-23 11:11:40 -0400632 ihold(bdev->bd_inode);
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700633 inode->i_bdev = bdev;
634 inode->i_mapping = bdev->bd_inode->i_mapping;
635 list_add(&inode->i_devices, &bdev->bd_inodes);
636 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637 spin_unlock(&bdev_lock);
638 }
639 return bdev;
640}
641
642/* Call when you free inode */
643
644void bd_forget(struct inode *inode)
645{
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700646 struct block_device *bdev = NULL;
647
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 spin_lock(&bdev_lock);
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700649 if (inode->i_bdev) {
Denis ChengRqc2acf7b2008-12-01 14:34:56 -0800650 if (!sb_is_blkdev_sb(inode->i_sb))
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700651 bdev = inode->i_bdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 __bd_forget(inode);
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700653 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 spin_unlock(&bdev_lock);
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700655
656 if (bdev)
657 iput(bdev->bd_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658}
659
Tejun Heo1a3cbbc2010-04-07 18:52:29 +0900660/**
661 * bd_may_claim - test whether a block device can be claimed
662 * @bdev: block device of interest
663 * @whole: whole block device containing @bdev, may equal @bdev
664 * @holder: holder trying to claim @bdev
665 *
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300666 * Test whether @bdev can be claimed by @holder.
Tejun Heo1a3cbbc2010-04-07 18:52:29 +0900667 *
668 * CONTEXT:
669 * spin_lock(&bdev_lock).
670 *
671 * RETURNS:
672 * %true if @bdev can be claimed, %false otherwise.
673 */
674static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
675 void *holder)
676{
677 if (bdev->bd_holder == holder)
678 return true; /* already a holder */
679 else if (bdev->bd_holder != NULL)
680 return false; /* held by someone else */
681 else if (bdev->bd_contains == bdev)
682 return true; /* is a whole device which isn't held */
683
Tejun Heoe525fd82010-11-13 11:55:17 +0100684 else if (whole->bd_holder == bd_may_claim)
Tejun Heo1a3cbbc2010-04-07 18:52:29 +0900685 return true; /* is a partition of a device that is being partitioned */
686 else if (whole->bd_holder != NULL)
687 return false; /* is a partition of a held device */
688 else
689 return true; /* is a partition of an un-held device */
690}
691
692/**
Tejun Heo6b4517a2010-04-07 18:53:59 +0900693 * bd_prepare_to_claim - prepare to claim a block device
694 * @bdev: block device of interest
695 * @whole: the whole device containing @bdev, may equal @bdev
696 * @holder: holder trying to claim @bdev
697 *
698 * Prepare to claim @bdev. This function fails if @bdev is already
699 * claimed by another holder and waits if another claiming is in
700 * progress. This function doesn't actually claim. On successful
701 * return, the caller has ownership of bd_claiming and bd_holder[s].
702 *
703 * CONTEXT:
704 * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab
705 * it multiple times.
706 *
707 * RETURNS:
708 * 0 if @bdev can be claimed, -EBUSY otherwise.
709 */
710static int bd_prepare_to_claim(struct block_device *bdev,
711 struct block_device *whole, void *holder)
712{
713retry:
714 /* if someone else claimed, fail */
715 if (!bd_may_claim(bdev, whole, holder))
716 return -EBUSY;
717
Tejun Heoe75aa852010-08-04 17:59:39 +0200718 /* if claiming is already in progress, wait for it to finish */
719 if (whole->bd_claiming) {
Tejun Heo6b4517a2010-04-07 18:53:59 +0900720 wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0);
721 DEFINE_WAIT(wait);
722
723 prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
724 spin_unlock(&bdev_lock);
725 schedule();
726 finish_wait(wq, &wait);
727 spin_lock(&bdev_lock);
728 goto retry;
729 }
730
731 /* yay, all mine */
732 return 0;
733}
734
735/**
736 * bd_start_claiming - start claiming a block device
737 * @bdev: block device of interest
738 * @holder: holder trying to claim @bdev
739 *
740 * @bdev is about to be opened exclusively. Check @bdev can be opened
741 * exclusively and mark that an exclusive open is in progress. Each
742 * successful call to this function must be matched with a call to
Nick Pigginb0018362010-05-26 01:51:19 +1000743 * either bd_finish_claiming() or bd_abort_claiming() (which do not
744 * fail).
745 *
746 * This function is used to gain exclusive access to the block device
747 * without actually causing other exclusive open attempts to fail. It
748 * should be used when the open sequence itself requires exclusive
749 * access but may subsequently fail.
Tejun Heo6b4517a2010-04-07 18:53:59 +0900750 *
751 * CONTEXT:
752 * Might sleep.
753 *
754 * RETURNS:
755 * Pointer to the block device containing @bdev on success, ERR_PTR()
756 * value on failure.
757 */
758static struct block_device *bd_start_claiming(struct block_device *bdev,
759 void *holder)
760{
761 struct gendisk *disk;
762 struct block_device *whole;
763 int partno, err;
764
765 might_sleep();
766
767 /*
768 * @bdev might not have been initialized properly yet, look up
769 * and grab the outer block device the hard way.
770 */
771 disk = get_gendisk(bdev->bd_dev, &partno);
772 if (!disk)
773 return ERR_PTR(-ENXIO);
774
Tejun Heod4c208b2011-06-13 12:45:48 +0200775 /*
776 * Normally, @bdev should equal what's returned from bdget_disk()
777 * if partno is 0; however, some drivers (floppy) use multiple
778 * bdev's for the same physical device and @bdev may be one of the
779 * aliases. Keep @bdev if partno is 0. This means claimer
780 * tracking is broken for those devices but it has always been that
781 * way.
782 */
783 if (partno)
784 whole = bdget_disk(disk, 0);
785 else
786 whole = bdgrab(bdev);
787
Nick Piggincf342572010-05-26 01:50:21 +1000788 module_put(disk->fops->owner);
Tejun Heo6b4517a2010-04-07 18:53:59 +0900789 put_disk(disk);
790 if (!whole)
791 return ERR_PTR(-ENOMEM);
792
793 /* prepare to claim, if successful, mark claiming in progress */
794 spin_lock(&bdev_lock);
795
796 err = bd_prepare_to_claim(bdev, whole, holder);
797 if (err == 0) {
798 whole->bd_claiming = holder;
799 spin_unlock(&bdev_lock);
800 return whole;
801 } else {
802 spin_unlock(&bdev_lock);
803 bdput(whole);
804 return ERR_PTR(err);
805 }
806}
807
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800808#ifdef CONFIG_SYSFS
Tejun Heo49731ba2011-01-14 18:43:57 +0100809struct bd_holder_disk {
810 struct list_head list;
811 struct gendisk *disk;
812 int refcnt;
813};
814
815static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev,
816 struct gendisk *disk)
817{
818 struct bd_holder_disk *holder;
819
820 list_for_each_entry(holder, &bdev->bd_holder_disks, list)
821 if (holder->disk == disk)
822 return holder;
823 return NULL;
824}
825
Andrew Morton4d7dd8f2006-09-29 01:58:56 -0700826static int add_symlink(struct kobject *from, struct kobject *to)
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800827{
Andrew Morton4d7dd8f2006-09-29 01:58:56 -0700828 return sysfs_create_link(from, to, kobject_name(to));
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800829}
830
831static void del_symlink(struct kobject *from, struct kobject *to)
832{
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800833 sysfs_remove_link(from, kobject_name(to));
834}
835
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800836/**
Tejun Heoe09b4572010-11-13 11:55:17 +0100837 * bd_link_disk_holder - create symlinks between holding disk and slave bdev
838 * @bdev: the claimed slave bdev
839 * @disk: the holding disk
Jun'ichi Nomuradf6c0cd2006-10-30 16:23:56 -0500840 *
Tejun Heo49731ba2011-01-14 18:43:57 +0100841 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
842 *
Tejun Heoe09b4572010-11-13 11:55:17 +0100843 * This functions creates the following sysfs symlinks.
Jun'ichi Nomuradf6c0cd2006-10-30 16:23:56 -0500844 *
Tejun Heoe09b4572010-11-13 11:55:17 +0100845 * - from "slaves" directory of the holder @disk to the claimed @bdev
846 * - from "holders" directory of the @bdev to the holder @disk
847 *
848 * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
849 * passed to bd_link_disk_holder(), then:
850 *
851 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
852 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
853 *
854 * The caller must have claimed @bdev before calling this function and
855 * ensure that both @bdev and @disk are valid during the creation and
856 * lifetime of these symlinks.
857 *
858 * CONTEXT:
859 * Might sleep.
860 *
861 * RETURNS:
862 * 0 on success, -errno on failure.
Jun'ichi Nomuradf6c0cd2006-10-30 16:23:56 -0500863 */
Tejun Heoe09b4572010-11-13 11:55:17 +0100864int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
Jun'ichi Nomuradf6c0cd2006-10-30 16:23:56 -0500865{
Tejun Heo49731ba2011-01-14 18:43:57 +0100866 struct bd_holder_disk *holder;
Tejun Heoe09b4572010-11-13 11:55:17 +0100867 int ret = 0;
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800868
Peter Zijlstra2e7b6512006-12-08 02:36:13 -0800869 mutex_lock(&bdev->bd_mutex);
Jun'ichi Nomuradf6c0cd2006-10-30 16:23:56 -0500870
Tejun Heo49731ba2011-01-14 18:43:57 +0100871 WARN_ON_ONCE(!bdev->bd_holder);
Johannes Weiner4e916722007-07-15 23:41:25 -0700872
Tejun Heoe09b4572010-11-13 11:55:17 +0100873 /* FIXME: remove the following once add_disk() handles errors */
874 if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir))
875 goto out_unlock;
Johannes Weiner4e916722007-07-15 23:41:25 -0700876
Tejun Heo49731ba2011-01-14 18:43:57 +0100877 holder = bd_find_holder_disk(bdev, disk);
878 if (holder) {
879 holder->refcnt++;
Tejun Heoe09b4572010-11-13 11:55:17 +0100880 goto out_unlock;
881 }
882
Tejun Heo49731ba2011-01-14 18:43:57 +0100883 holder = kzalloc(sizeof(*holder), GFP_KERNEL);
884 if (!holder) {
885 ret = -ENOMEM;
886 goto out_unlock;
887 }
888
889 INIT_LIST_HEAD(&holder->list);
890 holder->disk = disk;
891 holder->refcnt = 1;
892
893 ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
894 if (ret)
895 goto out_free;
896
897 ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj);
898 if (ret)
899 goto out_del;
Tejun Heoe7407d12011-02-24 09:56:32 +0100900 /*
901 * bdev could be deleted beneath us which would implicitly destroy
902 * the holder directory. Hold on to it.
903 */
904 kobject_get(bdev->bd_part->holder_dir);
Tejun Heo49731ba2011-01-14 18:43:57 +0100905
906 list_add(&holder->list, &bdev->bd_holder_disks);
907 goto out_unlock;
908
909out_del:
910 del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
911out_free:
912 kfree(holder);
Tejun Heoe09b4572010-11-13 11:55:17 +0100913out_unlock:
Jun'ichi Nomurab4cf1b72006-03-27 01:18:00 -0800914 mutex_unlock(&bdev->bd_mutex);
Tejun Heoe09b4572010-11-13 11:55:17 +0100915 return ret;
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800916}
Tejun Heoe09b4572010-11-13 11:55:17 +0100917EXPORT_SYMBOL_GPL(bd_link_disk_holder);
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800918
Tejun Heo49731ba2011-01-14 18:43:57 +0100919/**
920 * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
921 * @bdev: the calimed slave bdev
922 * @disk: the holding disk
923 *
924 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
925 *
926 * CONTEXT:
927 * Might sleep.
928 */
929void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800930{
Tejun Heo49731ba2011-01-14 18:43:57 +0100931 struct bd_holder_disk *holder;
Tejun Heoe09b4572010-11-13 11:55:17 +0100932
Tejun Heo49731ba2011-01-14 18:43:57 +0100933 mutex_lock(&bdev->bd_mutex);
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800934
Tejun Heo49731ba2011-01-14 18:43:57 +0100935 holder = bd_find_holder_disk(bdev, disk);
936
937 if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) {
938 del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
939 del_symlink(bdev->bd_part->holder_dir,
940 &disk_to_dev(disk)->kobj);
Tejun Heoe7407d12011-02-24 09:56:32 +0100941 kobject_put(bdev->bd_part->holder_dir);
Tejun Heo49731ba2011-01-14 18:43:57 +0100942 list_del_init(&holder->list);
943 kfree(holder);
944 }
945
946 mutex_unlock(&bdev->bd_mutex);
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800947}
Tejun Heo49731ba2011-01-14 18:43:57 +0100948EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800949#endif
950
Andrew Patterson0c002c22008-09-04 14:27:20 -0600951/**
Andrew Patterson56ade442008-09-04 14:27:40 -0600952 * flush_disk - invalidates all buffer-cache entries on a disk
953 *
954 * @bdev: struct block device to be flushed
Randy Dunlape6eb5ce2011-02-26 10:54:00 -0800955 * @kill_dirty: flag to guide handling of dirty inodes
Andrew Patterson56ade442008-09-04 14:27:40 -0600956 *
957 * Invalidates all buffer-cache entries on a disk. It should be called
958 * when a disk has been changed -- either by a media change or online
959 * resize.
960 */
NeilBrown93b270f2011-02-24 17:25:47 +1100961static void flush_disk(struct block_device *bdev, bool kill_dirty)
Andrew Patterson56ade442008-09-04 14:27:40 -0600962{
NeilBrown93b270f2011-02-24 17:25:47 +1100963 if (__invalidate_device(bdev, kill_dirty)) {
Andrew Patterson56ade442008-09-04 14:27:40 -0600964 char name[BDEVNAME_SIZE] = "";
965
966 if (bdev->bd_disk)
967 disk_name(bdev->bd_disk, 0, name);
968 printk(KERN_WARNING "VFS: busy inodes on changed media or "
969 "resized disk %s\n", name);
970 }
971
972 if (!bdev->bd_disk)
973 return;
974 if (disk_partitionable(bdev->bd_disk))
975 bdev->bd_invalidated = 1;
976}
977
978/**
Randy Dunlap57d1b532008-10-09 10:42:38 +0200979 * check_disk_size_change - checks for disk size change and adjusts bdev size.
Andrew Pattersonc3279d12008-09-04 14:27:25 -0600980 * @disk: struct gendisk to check
981 * @bdev: struct bdev to adjust.
982 *
983 * This routine checks to see if the bdev size does not match the disk size
984 * and adjusts it if it differs.
985 */
986void check_disk_size_change(struct gendisk *disk, struct block_device *bdev)
987{
988 loff_t disk_size, bdev_size;
989
990 disk_size = (loff_t)get_capacity(disk) << 9;
991 bdev_size = i_size_read(bdev->bd_inode);
992 if (disk_size != bdev_size) {
993 char name[BDEVNAME_SIZE];
994
995 disk_name(disk, 0, name);
996 printk(KERN_INFO
997 "%s: detected capacity change from %lld to %lld\n",
998 name, bdev_size, disk_size);
999 i_size_write(bdev->bd_inode, disk_size);
NeilBrown93b270f2011-02-24 17:25:47 +11001000 flush_disk(bdev, false);
Andrew Pattersonc3279d12008-09-04 14:27:25 -06001001 }
1002}
1003EXPORT_SYMBOL(check_disk_size_change);
1004
1005/**
Randy Dunlap57d1b532008-10-09 10:42:38 +02001006 * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
Andrew Patterson0c002c22008-09-04 14:27:20 -06001007 * @disk: struct gendisk to be revalidated
1008 *
1009 * This routine is a wrapper for lower-level driver's revalidate_disk
1010 * call-backs. It is used to do common pre and post operations needed
1011 * for all revalidate_disk operations.
1012 */
1013int revalidate_disk(struct gendisk *disk)
1014{
Andrew Pattersonc3279d12008-09-04 14:27:25 -06001015 struct block_device *bdev;
Andrew Patterson0c002c22008-09-04 14:27:20 -06001016 int ret = 0;
1017
1018 if (disk->fops->revalidate_disk)
1019 ret = disk->fops->revalidate_disk(disk);
1020
Andrew Pattersonc3279d12008-09-04 14:27:25 -06001021 bdev = bdget_disk(disk, 0);
1022 if (!bdev)
1023 return ret;
1024
1025 mutex_lock(&bdev->bd_mutex);
1026 check_disk_size_change(disk, bdev);
1027 mutex_unlock(&bdev->bd_mutex);
1028 bdput(bdev);
Andrew Patterson0c002c22008-09-04 14:27:20 -06001029 return ret;
1030}
1031EXPORT_SYMBOL(revalidate_disk);
1032
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033/*
1034 * This routine checks whether a removable media has been changed,
1035 * and invalidates all buffer-cache-entries in that case. This
1036 * is a relatively slow routine, so we have to try to minimize using
1037 * it. Thus it is called only upon a 'mount' or 'open'. This
1038 * is the best way of combining speed and utility, I think.
1039 * People changing diskettes in the middle of an operation deserve
1040 * to lose :-)
1041 */
1042int check_disk_change(struct block_device *bdev)
1043{
1044 struct gendisk *disk = bdev->bd_disk;
Alexey Dobriyan83d5cde2009-09-21 17:01:13 -07001045 const struct block_device_operations *bdops = disk->fops;
Tejun Heo77ea8872010-12-08 20:57:37 +01001046 unsigned int events;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001047
Tejun Heo77ea8872010-12-08 20:57:37 +01001048 events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE |
1049 DISK_EVENT_EJECT_REQUEST);
1050 if (!(events & DISK_EVENT_MEDIA_CHANGE))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001051 return 0;
1052
NeilBrown93b270f2011-02-24 17:25:47 +11001053 flush_disk(bdev, true);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001054 if (bdops->revalidate_disk)
1055 bdops->revalidate_disk(bdev->bd_disk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001056 return 1;
1057}
1058
1059EXPORT_SYMBOL(check_disk_change);
1060
1061void bd_set_size(struct block_device *bdev, loff_t size)
1062{
Martin K. Petersene1defc42009-05-22 17:17:49 -04001063 unsigned bsize = bdev_logical_block_size(bdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064
1065 bdev->bd_inode->i_size = size;
1066 while (bsize < PAGE_CACHE_SIZE) {
1067 if (size & bsize)
1068 break;
1069 bsize <<= 1;
1070 }
1071 bdev->bd_block_size = bsize;
1072 bdev->bd_inode->i_blkbits = blksize_bits(bsize);
1073}
1074EXPORT_SYMBOL(bd_set_size);
1075
Al Viro9a1c3542008-02-22 20:40:24 -05001076static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
NeilBrown37be4122006-12-08 02:36:16 -08001077
Peter Zijlstra6d740cd2007-02-20 13:58:18 -08001078/*
1079 * bd_mutex locking:
1080 *
1081 * mutex_lock(part->bd_mutex)
1082 * mutex_lock_nested(whole->bd_mutex, 1)
1083 */
1084
Al Viro572c4892007-10-08 13:24:05 -04001085static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087 struct gendisk *disk;
Pavel Emelyanov7db9cfd2008-06-05 22:46:27 -07001088 int ret;
Tejun Heocf771cb2008-09-03 09:01:09 +02001089 int partno;
Al Virofe6e9c12008-06-23 08:30:55 -04001090 int perm = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001091
Al Viro572c4892007-10-08 13:24:05 -04001092 if (mode & FMODE_READ)
Al Virofe6e9c12008-06-23 08:30:55 -04001093 perm |= MAY_READ;
Al Viro572c4892007-10-08 13:24:05 -04001094 if (mode & FMODE_WRITE)
Al Virofe6e9c12008-06-23 08:30:55 -04001095 perm |= MAY_WRITE;
1096 /*
1097 * hooks: /n/, see "layering violations".
1098 */
Chris Wrightb7300b72010-08-10 18:02:55 -07001099 if (!for_part) {
1100 ret = devcgroup_inode_permission(bdev->bd_inode, perm);
1101 if (ret != 0) {
1102 bdput(bdev);
1103 return ret;
1104 }
Al Viro82666022008-08-01 05:32:04 -04001105 }
Pavel Emelyanov7db9cfd2008-06-05 22:46:27 -07001106
NeilBrownd3374822009-01-09 08:31:10 +11001107 restart:
Tejun Heo0762b8b2008-08-25 19:56:12 +09001108
Tejun Heo89f97492008-11-05 10:21:06 +01001109 ret = -ENXIO;
Tejun Heocf771cb2008-09-03 09:01:09 +02001110 disk = get_gendisk(bdev->bd_dev, &partno);
Tejun Heo0762b8b2008-08-25 19:56:12 +09001111 if (!disk)
Arnd Bergmann6e9624b2010-08-07 18:25:34 +02001112 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113
Tejun Heo69e02c52011-03-09 19:54:27 +01001114 disk_block_events(disk);
NeilBrown6796bf52006-12-08 02:36:16 -08001115 mutex_lock_nested(&bdev->bd_mutex, for_part);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 if (!bdev->bd_openers) {
1117 bdev->bd_disk = disk;
1118 bdev->bd_contains = bdev;
Tejun Heocf771cb2008-09-03 09:01:09 +02001119 if (!partno) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001120 struct backing_dev_info *bdi;
Tejun Heo89f97492008-11-05 10:21:06 +01001121
1122 ret = -ENXIO;
1123 bdev->bd_part = disk_get_part(disk, partno);
1124 if (!bdev->bd_part)
1125 goto out_clear;
1126
Tejun Heo1196f8b2011-04-21 20:54:45 +02001127 ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001128 if (disk->fops->open) {
Al Viro572c4892007-10-08 13:24:05 -04001129 ret = disk->fops->open(bdev, mode);
NeilBrownd3374822009-01-09 08:31:10 +11001130 if (ret == -ERESTARTSYS) {
1131 /* Lost a race with 'disk' being
1132 * deleted, try again.
1133 * See md.c
1134 */
1135 disk_put_part(bdev->bd_part);
1136 bdev->bd_part = NULL;
NeilBrownd3374822009-01-09 08:31:10 +11001137 bdev->bd_disk = NULL;
1138 mutex_unlock(&bdev->bd_mutex);
Tejun Heo69e02c52011-03-09 19:54:27 +01001139 disk_unblock_events(disk);
1140 module_put(disk->fops->owner);
1141 put_disk(disk);
NeilBrownd3374822009-01-09 08:31:10 +11001142 goto restart;
1143 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144 }
Tejun Heo7e697232011-05-23 13:26:07 +02001145
1146 if (!ret && !bdev->bd_openers) {
1147 bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);
1148 bdi = blk_get_backing_dev_info(bdev);
1149 if (bdi == NULL)
1150 bdi = &default_backing_dev_info;
1151 bdev_inode_switch_bdi(bdev->bd_inode, bdi);
1152 }
1153
Tejun Heo1196f8b2011-04-21 20:54:45 +02001154 /*
1155 * If the device is invalidated, rescan partition
1156 * if open succeeded or failed with -ENOMEDIUM.
1157 * The latter is necessary to prevent ghost
1158 * partitions on a removed medium.
1159 */
1160 if (bdev->bd_invalidated && (!ret || ret == -ENOMEDIUM))
1161 rescan_partitions(disk, bdev);
1162 if (ret)
1163 goto out_clear;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165 struct block_device *whole;
1166 whole = bdget_disk(disk, 0);
1167 ret = -ENOMEM;
1168 if (!whole)
Tejun Heo0762b8b2008-08-25 19:56:12 +09001169 goto out_clear;
NeilBrown37be4122006-12-08 02:36:16 -08001170 BUG_ON(for_part);
Al Viro572c4892007-10-08 13:24:05 -04001171 ret = __blkdev_get(whole, mode, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172 if (ret)
Tejun Heo0762b8b2008-08-25 19:56:12 +09001173 goto out_clear;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174 bdev->bd_contains = whole;
Dave Chinnera5491e02010-10-21 11:49:26 +11001175 bdev_inode_switch_bdi(bdev->bd_inode,
1176 whole->bd_inode->i_data.backing_dev_info);
Tejun Heo89f97492008-11-05 10:21:06 +01001177 bdev->bd_part = disk_get_part(disk, partno);
Tejun Heoe71bf0d2008-09-03 09:03:02 +02001178 if (!(disk->flags & GENHD_FL_UP) ||
Tejun Heo89f97492008-11-05 10:21:06 +01001179 !bdev->bd_part || !bdev->bd_part->nr_sects) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180 ret = -ENXIO;
Tejun Heo0762b8b2008-08-25 19:56:12 +09001181 goto out_clear;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182 }
Tejun Heo89f97492008-11-05 10:21:06 +01001183 bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001184 }
1185 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001186 if (bdev->bd_contains == bdev) {
Tejun Heo1196f8b2011-04-21 20:54:45 +02001187 ret = 0;
1188 if (bdev->bd_disk->fops->open)
Al Viro572c4892007-10-08 13:24:05 -04001189 ret = bdev->bd_disk->fops->open(bdev, mode);
Tejun Heo1196f8b2011-04-21 20:54:45 +02001190 /* the same as first opener case, read comment there */
1191 if (bdev->bd_invalidated && (!ret || ret == -ENOMEDIUM))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001192 rescan_partitions(bdev->bd_disk, bdev);
Tejun Heo1196f8b2011-04-21 20:54:45 +02001193 if (ret)
1194 goto out_unlock_bdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195 }
Tejun Heo69e02c52011-03-09 19:54:27 +01001196 /* only one opener holds refs to the module and disk */
1197 module_put(disk->fops->owner);
1198 put_disk(disk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001199 }
1200 bdev->bd_openers++;
NeilBrown37be4122006-12-08 02:36:16 -08001201 if (for_part)
1202 bdev->bd_part_count++;
Arjan van de Venc039e312006-03-23 03:00:28 -08001203 mutex_unlock(&bdev->bd_mutex);
Tejun Heo69e02c52011-03-09 19:54:27 +01001204 disk_unblock_events(disk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205 return 0;
1206
Tejun Heo0762b8b2008-08-25 19:56:12 +09001207 out_clear:
Tejun Heo89f97492008-11-05 10:21:06 +01001208 disk_put_part(bdev->bd_part);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 bdev->bd_disk = NULL;
Tejun Heo0762b8b2008-08-25 19:56:12 +09001210 bdev->bd_part = NULL;
Dave Chinnera5491e02010-10-21 11:49:26 +11001211 bdev_inode_switch_bdi(bdev->bd_inode, &default_backing_dev_info);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001212 if (bdev != bdev->bd_contains)
Al Viro572c4892007-10-08 13:24:05 -04001213 __blkdev_put(bdev->bd_contains, mode, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214 bdev->bd_contains = NULL;
Tejun Heo0762b8b2008-08-25 19:56:12 +09001215 out_unlock_bdev:
Arjan van de Venc039e312006-03-23 03:00:28 -08001216 mutex_unlock(&bdev->bd_mutex);
Tejun Heo69e02c52011-03-09 19:54:27 +01001217 disk_unblock_events(disk);
Tejun Heo69e02c52011-03-09 19:54:27 +01001218 module_put(disk->fops->owner);
Tejun Heo0762b8b2008-08-25 19:56:12 +09001219 put_disk(disk);
Dan Carpenter4345cab2011-03-19 13:53:31 +01001220 out:
Tejun Heo0762b8b2008-08-25 19:56:12 +09001221 bdput(bdev);
1222
Linus Torvalds1da177e2005-04-16 15:20:36 -07001223 return ret;
1224}
1225
Tejun Heod4d77622010-11-13 11:55:18 +01001226/**
1227 * blkdev_get - open a block device
1228 * @bdev: block_device to open
1229 * @mode: FMODE_* mask
1230 * @holder: exclusive holder identifier
1231 *
1232 * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is
1233 * open with exclusive access. Specifying %FMODE_EXCL with %NULL
1234 * @holder is invalid. Exclusive opens may nest for the same @holder.
1235 *
1236 * On success, the reference count of @bdev is unchanged. On failure,
1237 * @bdev is put.
1238 *
1239 * CONTEXT:
1240 * Might sleep.
1241 *
1242 * RETURNS:
1243 * 0 on success, -errno on failure.
1244 */
Tejun Heoe525fd82010-11-13 11:55:17 +01001245int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246{
Tejun Heoe525fd82010-11-13 11:55:17 +01001247 struct block_device *whole = NULL;
1248 int res;
1249
1250 WARN_ON_ONCE((mode & FMODE_EXCL) && !holder);
1251
1252 if ((mode & FMODE_EXCL) && holder) {
1253 whole = bd_start_claiming(bdev, holder);
1254 if (IS_ERR(whole)) {
1255 bdput(bdev);
1256 return PTR_ERR(whole);
1257 }
1258 }
1259
1260 res = __blkdev_get(bdev, mode, 0);
1261
1262 if (whole) {
Tejun Heod4dc2102011-04-21 20:54:46 +02001263 struct gendisk *disk = whole->bd_disk;
1264
Tejun Heo6a027ef2010-11-13 11:55:17 +01001265 /* finish claiming */
Tejun Heo77ea8872010-12-08 20:57:37 +01001266 mutex_lock(&bdev->bd_mutex);
Tejun Heo6a027ef2010-11-13 11:55:17 +01001267 spin_lock(&bdev_lock);
1268
Tejun Heo77ea8872010-12-08 20:57:37 +01001269 if (!res) {
Tejun Heo6a027ef2010-11-13 11:55:17 +01001270 BUG_ON(!bd_may_claim(bdev, whole, holder));
1271 /*
1272 * Note that for a whole device bd_holders
1273 * will be incremented twice, and bd_holder
1274 * will be set to bd_may_claim before being
1275 * set to holder
1276 */
1277 whole->bd_holders++;
1278 whole->bd_holder = bd_may_claim;
1279 bdev->bd_holders++;
1280 bdev->bd_holder = holder;
1281 }
1282
1283 /* tell others that we're done */
1284 BUG_ON(whole->bd_claiming != holder);
1285 whole->bd_claiming = NULL;
1286 wake_up_bit(&whole->bd_claiming, 0);
1287
1288 spin_unlock(&bdev_lock);
Tejun Heo77ea8872010-12-08 20:57:37 +01001289
1290 /*
Tejun Heod4dc2102011-04-21 20:54:46 +02001291 * Block event polling for write claims if requested. Any
1292 * write holder makes the write_holder state stick until
1293 * all are released. This is good enough and tracking
1294 * individual writeable reference is too fragile given the
1295 * way @mode is used in blkdev_get/put().
Tejun Heo77ea8872010-12-08 20:57:37 +01001296 */
Tejun Heo4c49ff32011-06-01 08:27:41 +02001297 if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder &&
1298 (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
Tejun Heo77ea8872010-12-08 20:57:37 +01001299 bdev->bd_write_holder = true;
Tejun Heod4dc2102011-04-21 20:54:46 +02001300 disk_block_events(disk);
Tejun Heo77ea8872010-12-08 20:57:37 +01001301 }
1302
1303 mutex_unlock(&bdev->bd_mutex);
Tejun Heo6a027ef2010-11-13 11:55:17 +01001304 bdput(whole);
Tejun Heoe525fd82010-11-13 11:55:17 +01001305 }
1306
1307 return res;
NeilBrown37be4122006-12-08 02:36:16 -08001308}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001309EXPORT_SYMBOL(blkdev_get);
1310
Tejun Heod4d77622010-11-13 11:55:18 +01001311/**
1312 * blkdev_get_by_path - open a block device by name
1313 * @path: path to the block device to open
1314 * @mode: FMODE_* mask
1315 * @holder: exclusive holder identifier
1316 *
1317 * Open the blockdevice described by the device file at @path. @mode
1318 * and @holder are identical to blkdev_get().
1319 *
1320 * On success, the returned block_device has reference count of one.
1321 *
1322 * CONTEXT:
1323 * Might sleep.
1324 *
1325 * RETURNS:
1326 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1327 */
1328struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
1329 void *holder)
1330{
1331 struct block_device *bdev;
1332 int err;
1333
1334 bdev = lookup_bdev(path);
1335 if (IS_ERR(bdev))
1336 return bdev;
1337
1338 err = blkdev_get(bdev, mode, holder);
1339 if (err)
1340 return ERR_PTR(err);
1341
Chuck Ebberte51900f2011-02-16 18:11:53 -05001342 if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) {
1343 blkdev_put(bdev, mode);
1344 return ERR_PTR(-EACCES);
1345 }
1346
Tejun Heod4d77622010-11-13 11:55:18 +01001347 return bdev;
1348}
1349EXPORT_SYMBOL(blkdev_get_by_path);
1350
1351/**
1352 * blkdev_get_by_dev - open a block device by device number
1353 * @dev: device number of block device to open
1354 * @mode: FMODE_* mask
1355 * @holder: exclusive holder identifier
1356 *
1357 * Open the blockdevice described by device number @dev. @mode and
1358 * @holder are identical to blkdev_get().
1359 *
1360 * Use it ONLY if you really do not have anything better - i.e. when
1361 * you are behind a truly sucky interface and all you are given is a
1362 * device number. _Never_ to be used for internal purposes. If you
1363 * ever need it - reconsider your API.
1364 *
1365 * On success, the returned block_device has reference count of one.
1366 *
1367 * CONTEXT:
1368 * Might sleep.
1369 *
1370 * RETURNS:
1371 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1372 */
1373struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
1374{
1375 struct block_device *bdev;
1376 int err;
1377
1378 bdev = bdget(dev);
1379 if (!bdev)
1380 return ERR_PTR(-ENOMEM);
1381
1382 err = blkdev_get(bdev, mode, holder);
1383 if (err)
1384 return ERR_PTR(err);
1385
1386 return bdev;
1387}
1388EXPORT_SYMBOL(blkdev_get_by_dev);
1389
Linus Torvalds1da177e2005-04-16 15:20:36 -07001390static int blkdev_open(struct inode * inode, struct file * filp)
1391{
1392 struct block_device *bdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001393
1394 /*
1395 * Preserve backwards compatibility and allow large file access
1396 * even if userspace doesn't ask for it explicitly. Some mkfs
1397 * binary needs it. We might want to drop this workaround
1398 * during an unstable branch.
1399 */
1400 filp->f_flags |= O_LARGEFILE;
1401
Al Viro572c4892007-10-08 13:24:05 -04001402 if (filp->f_flags & O_NDELAY)
1403 filp->f_mode |= FMODE_NDELAY;
1404 if (filp->f_flags & O_EXCL)
1405 filp->f_mode |= FMODE_EXCL;
1406 if ((filp->f_flags & O_ACCMODE) == 3)
1407 filp->f_mode |= FMODE_WRITE_IOCTL;
1408
Linus Torvalds1da177e2005-04-16 15:20:36 -07001409 bdev = bd_acquire(inode);
Pavel Emelianov6a2aae02006-10-28 10:38:33 -07001410 if (bdev == NULL)
1411 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412
Al Viro572c4892007-10-08 13:24:05 -04001413 filp->f_mapping = bdev->bd_inode->i_mapping;
1414
Tejun Heoe525fd82010-11-13 11:55:17 +01001415 return blkdev_get(bdev, filp->f_mode, filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001416}
1417
Al Viro9a1c3542008-02-22 20:40:24 -05001418static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001419{
1420 int ret = 0;
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001421 struct gendisk *disk = bdev->bd_disk;
NeilBrown37be4122006-12-08 02:36:16 -08001422 struct block_device *victim = NULL;
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001423
NeilBrown6796bf52006-12-08 02:36:16 -08001424 mutex_lock_nested(&bdev->bd_mutex, for_part);
NeilBrown37be4122006-12-08 02:36:16 -08001425 if (for_part)
1426 bdev->bd_part_count--;
1427
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001428 if (!--bdev->bd_openers) {
Tejun Heo6a027ef2010-11-13 11:55:17 +01001429 WARN_ON_ONCE(bdev->bd_holders);
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001430 sync_blockdev(bdev);
1431 kill_bdev(bdev);
NeilBrown94007752011-09-10 17:20:21 +10001432 /* ->release can cause the old bdi to disappear,
1433 * so must switch it out first
1434 */
1435 bdev_inode_switch_bdi(bdev->bd_inode,
1436 &default_backing_dev_info);
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001437 }
1438 if (bdev->bd_contains == bdev) {
1439 if (disk->fops->release)
Al Viro9a1c3542008-02-22 20:40:24 -05001440 ret = disk->fops->release(disk, mode);
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001441 }
1442 if (!bdev->bd_openers) {
1443 struct module *owner = disk->fops->owner;
1444
1445 put_disk(disk);
1446 module_put(owner);
Tejun Heo0762b8b2008-08-25 19:56:12 +09001447 disk_put_part(bdev->bd_part);
1448 bdev->bd_part = NULL;
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001449 bdev->bd_disk = NULL;
NeilBrown37be4122006-12-08 02:36:16 -08001450 if (bdev != bdev->bd_contains)
1451 victim = bdev->bd_contains;
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001452 bdev->bd_contains = NULL;
1453 }
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001454 mutex_unlock(&bdev->bd_mutex);
1455 bdput(bdev);
NeilBrown37be4122006-12-08 02:36:16 -08001456 if (victim)
Al Viro9a1c3542008-02-22 20:40:24 -05001457 __blkdev_put(victim, mode, 1);
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001458 return ret;
1459}
1460
Al Viro9a1c3542008-02-22 20:40:24 -05001461int blkdev_put(struct block_device *bdev, fmode_t mode)
NeilBrown37be4122006-12-08 02:36:16 -08001462{
Tejun Heo85ef06d2011-07-01 16:17:47 +02001463 mutex_lock(&bdev->bd_mutex);
1464
Tejun Heoe525fd82010-11-13 11:55:17 +01001465 if (mode & FMODE_EXCL) {
Tejun Heo6a027ef2010-11-13 11:55:17 +01001466 bool bdev_free;
1467
1468 /*
1469 * Release a claim on the device. The holder fields
1470 * are protected with bdev_lock. bd_mutex is to
1471 * synchronize disk_holder unlinking.
1472 */
Tejun Heo6a027ef2010-11-13 11:55:17 +01001473 spin_lock(&bdev_lock);
1474
1475 WARN_ON_ONCE(--bdev->bd_holders < 0);
1476 WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0);
1477
1478 /* bd_contains might point to self, check in a separate step */
1479 if ((bdev_free = !bdev->bd_holders))
1480 bdev->bd_holder = NULL;
1481 if (!bdev->bd_contains->bd_holders)
1482 bdev->bd_contains->bd_holder = NULL;
1483
1484 spin_unlock(&bdev_lock);
1485
Tejun Heo77ea8872010-12-08 20:57:37 +01001486 /*
1487 * If this was the last claim, remove holder link and
1488 * unblock evpoll if it was a write holder.
1489 */
Tejun Heo85ef06d2011-07-01 16:17:47 +02001490 if (bdev_free && bdev->bd_write_holder) {
1491 disk_unblock_events(bdev->bd_disk);
1492 bdev->bd_write_holder = false;
Tejun Heo77ea8872010-12-08 20:57:37 +01001493 }
Tejun Heo69362172011-03-09 19:54:27 +01001494 }
Tejun Heo77ea8872010-12-08 20:57:37 +01001495
Tejun Heo85ef06d2011-07-01 16:17:47 +02001496 /*
1497 * Trigger event checking and tell drivers to flush MEDIA_CHANGE
1498 * event. This is to ensure detection of media removal commanded
1499 * from userland - e.g. eject(1).
1500 */
1501 disk_flush_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE);
1502
1503 mutex_unlock(&bdev->bd_mutex);
1504
Al Viro9a1c3542008-02-22 20:40:24 -05001505 return __blkdev_put(bdev, mode, 0);
NeilBrown37be4122006-12-08 02:36:16 -08001506}
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001507EXPORT_SYMBOL(blkdev_put);
1508
Linus Torvalds1da177e2005-04-16 15:20:36 -07001509static int blkdev_close(struct inode * inode, struct file * filp)
1510{
1511 struct block_device *bdev = I_BDEV(filp->f_mapping->host);
Tejun Heoe525fd82010-11-13 11:55:17 +01001512
Al Viro9a1c3542008-02-22 20:40:24 -05001513 return blkdev_put(bdev, filp->f_mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001514}
1515
Arnd Bergmannbb93e3a2005-06-23 00:10:15 -07001516static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001517{
Al Viro56b26ad2008-09-19 03:17:36 -04001518 struct block_device *bdev = I_BDEV(file->f_mapping->host);
1519 fmode_t mode = file->f_mode;
Christoph Hellwigfd4ce1a2008-11-05 14:58:42 +01001520
1521 /*
1522 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
1523 * to updated it before every ioctl.
1524 */
Al Viro56b26ad2008-09-19 03:17:36 -04001525 if (file->f_flags & O_NDELAY)
Christoph Hellwigfd4ce1a2008-11-05 14:58:42 +01001526 mode |= FMODE_NDELAY;
1527 else
1528 mode &= ~FMODE_NDELAY;
1529
Al Viro56b26ad2008-09-19 03:17:36 -04001530 return blkdev_ioctl(bdev, mode, cmd, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001531}
1532
Theodore Ts'o87d8fe12009-01-03 09:47:09 -05001533/*
Christoph Hellwigeef99382009-08-20 17:43:41 +02001534 * Write data to the block device. Only intended for the block device itself
1535 * and the raw driver which basically is a fake block device.
1536 *
1537 * Does not take i_mutex for the write and thus is not for general purpose
1538 * use.
1539 */
1540ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
1541 unsigned long nr_segs, loff_t pos)
1542{
1543 struct file *file = iocb->ki_filp;
1544 ssize_t ret;
1545
1546 BUG_ON(iocb->ki_pos != pos);
1547
1548 ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
1549 if (ret > 0 || ret == -EIOCBQUEUED) {
1550 ssize_t err;
1551
1552 err = generic_write_sync(file, pos, ret);
1553 if (err < 0 && ret > 0)
1554 ret = err;
1555 }
1556 return ret;
1557}
1558EXPORT_SYMBOL_GPL(blkdev_aio_write);
1559
1560/*
Theodore Ts'o87d8fe12009-01-03 09:47:09 -05001561 * Try to release a page associated with block device when the system
1562 * is under memory pressure.
1563 */
1564static int blkdev_releasepage(struct page *page, gfp_t wait)
1565{
1566 struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super;
1567
1568 if (super && super->s_op->bdev_try_to_free_page)
1569 return super->s_op->bdev_try_to_free_page(super, page, wait);
1570
1571 return try_to_free_buffers(page);
1572}
1573
Adrian Bunk4c54ac62008-02-18 13:48:31 +01001574static const struct address_space_operations def_blk_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001575 .readpage = blkdev_readpage,
1576 .writepage = blkdev_writepage,
Nick Piggin6272b5a2007-10-16 01:25:04 -07001577 .write_begin = blkdev_write_begin,
1578 .write_end = blkdev_write_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001579 .writepages = generic_writepages,
Theodore Ts'o87d8fe12009-01-03 09:47:09 -05001580 .releasepage = blkdev_releasepage,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001581 .direct_IO = blkdev_direct_IO,
1582};
1583
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -08001584const struct file_operations def_blk_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001585 .open = blkdev_open,
1586 .release = blkdev_close,
1587 .llseek = block_llseek,
Badari Pulavarty543ade12006-09-30 23:28:48 -07001588 .read = do_sync_read,
1589 .write = do_sync_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001590 .aio_read = generic_file_aio_read,
Christoph Hellwigeef99382009-08-20 17:43:41 +02001591 .aio_write = blkdev_aio_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001592 .mmap = generic_file_mmap,
Andrew Mortonb1dd3b22010-04-06 14:35:00 -07001593 .fsync = blkdev_fsync,
Arnd Bergmannbb93e3a2005-06-23 00:10:15 -07001594 .unlocked_ioctl = block_ioctl,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001595#ifdef CONFIG_COMPAT
1596 .compat_ioctl = compat_blkdev_ioctl,
1597#endif
Jens Axboe7f9c51f2006-05-01 19:59:32 +02001598 .splice_read = generic_file_splice_read,
1599 .splice_write = generic_file_splice_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001600};
1601
1602int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg)
1603{
1604 int res;
1605 mm_segment_t old_fs = get_fs();
1606 set_fs(KERNEL_DS);
Al Viro56b26ad2008-09-19 03:17:36 -04001607 res = blkdev_ioctl(bdev, 0, cmd, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001608 set_fs(old_fs);
1609 return res;
1610}
1611
1612EXPORT_SYMBOL(ioctl_by_bdev);
1613
1614/**
1615 * lookup_bdev - lookup a struct block_device by name
Randy Dunlap94e29592009-01-06 14:41:15 -08001616 * @pathname: special file representing the block device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001617 *
Randy Dunlap57d1b532008-10-09 10:42:38 +02001618 * Get a reference to the blockdevice at @pathname in the current
Linus Torvalds1da177e2005-04-16 15:20:36 -07001619 * namespace if possible and return it. Return ERR_PTR(error)
1620 * otherwise.
1621 */
Al Viro421748e2008-08-02 01:04:36 -04001622struct block_device *lookup_bdev(const char *pathname)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001623{
1624 struct block_device *bdev;
1625 struct inode *inode;
Al Viro421748e2008-08-02 01:04:36 -04001626 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001627 int error;
1628
Al Viro421748e2008-08-02 01:04:36 -04001629 if (!pathname || !*pathname)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001630 return ERR_PTR(-EINVAL);
1631
Al Viro421748e2008-08-02 01:04:36 -04001632 error = kern_path(pathname, LOOKUP_FOLLOW, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001633 if (error)
1634 return ERR_PTR(error);
1635
Al Viro421748e2008-08-02 01:04:36 -04001636 inode = path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001637 error = -ENOTBLK;
1638 if (!S_ISBLK(inode->i_mode))
1639 goto fail;
1640 error = -EACCES;
Al Viro421748e2008-08-02 01:04:36 -04001641 if (path.mnt->mnt_flags & MNT_NODEV)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001642 goto fail;
1643 error = -ENOMEM;
1644 bdev = bd_acquire(inode);
1645 if (!bdev)
1646 goto fail;
1647out:
Al Viro421748e2008-08-02 01:04:36 -04001648 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001649 return bdev;
1650fail:
1651 bdev = ERR_PTR(error);
1652 goto out;
1653}
Al Virod5686b42008-08-01 05:00:11 -04001654EXPORT_SYMBOL(lookup_bdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001655
NeilBrown93b270f2011-02-24 17:25:47 +11001656int __invalidate_device(struct block_device *bdev, bool kill_dirty)
David Howellsb71e8a42006-08-29 19:06:11 +01001657{
1658 struct super_block *sb = get_super(bdev);
1659 int res = 0;
1660
1661 if (sb) {
1662 /*
1663 * no need to lock the super, get_super holds the
1664 * read mutex so the filesystem cannot go away
1665 * under us (->put_super runs with the write lock
1666 * hold).
1667 */
1668 shrink_dcache_sb(sb);
NeilBrown93b270f2011-02-24 17:25:47 +11001669 res = invalidate_inodes(sb, kill_dirty);
David Howellsb71e8a42006-08-29 19:06:11 +01001670 drop_super(sb);
1671 }
Peter Zijlstraf98393a2007-05-06 14:49:54 -07001672 invalidate_bdev(bdev);
David Howellsb71e8a42006-08-29 19:06:11 +01001673 return res;
1674}
1675EXPORT_SYMBOL(__invalidate_device);