blob: 552a8d13bc321f4d1cf64fb9b3171893e28e73e9 [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>
Muthu Kumarb502bd12012-03-23 15:01:50 -070019#include <linux/magic.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include <linux/buffer_head.h>
Al Viroff01bb42011-09-16 02:31:11 -040021#include <linux/swap.h>
Nick Piggin585d3bc2009-02-25 10:44:19 +010022#include <linux/pagevec.h>
David Howells811d7362006-08-29 19:06:09 +010023#include <linux/writeback.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <linux/mpage.h>
25#include <linux/mount.h>
26#include <linux/uio.h>
27#include <linux/namei.h>
Vignesh Babu BM1368c4f2007-05-08 00:24:32 -070028#include <linux/log2.h>
Al Viroff01bb42011-09-16 02:31:11 -040029#include <linux/cleancache.h>
Kent Overstreeta27bb332013-05-07 16:19:08 -070030#include <linux/aio.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031#include <asm/uaccess.h>
David Howells07f3f05c2006-09-30 20:52:18 +020032#include "internal.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34struct bdev_inode {
35 struct block_device bdev;
36 struct inode vfs_inode;
37};
38
Adrian Bunk4c54ac62008-02-18 13:48:31 +010039static const struct address_space_operations def_blk_aops;
40
Linus Torvalds1da177e2005-04-16 15:20:36 -070041static inline struct bdev_inode *BDEV_I(struct inode *inode)
42{
43 return container_of(inode, struct bdev_inode, vfs_inode);
44}
45
46inline struct block_device *I_BDEV(struct inode *inode)
47{
48 return &BDEV_I(inode)->bdev;
49}
Linus Torvalds1da177e2005-04-16 15:20:36 -070050EXPORT_SYMBOL(I_BDEV);
51
Dave Chinnera5491e02010-10-21 11:49:26 +110052/*
Christoph Hellwigf758eea2011-04-21 18:19:44 -060053 * Move the inode from its current bdi to a new bdi. If the inode is dirty we
54 * need to move it onto the dirty list of @dst so that the inode is always on
55 * the right list.
Dave Chinnera5491e02010-10-21 11:49:26 +110056 */
57static void bdev_inode_switch_bdi(struct inode *inode,
58 struct backing_dev_info *dst)
59{
Christoph Hellwigf758eea2011-04-21 18:19:44 -060060 struct backing_dev_info *old = inode->i_data.backing_dev_info;
Jan Karaa5faeaf2013-06-28 16:04:02 +020061 bool wakeup_bdi = false;
Christoph Hellwigf758eea2011-04-21 18:19:44 -060062
63 if (unlikely(dst == old)) /* deadlock avoidance */
64 return;
65 bdi_lock_two(&old->wb, &dst->wb);
Dave Chinner250df6e2011-03-22 22:23:36 +110066 spin_lock(&inode->i_lock);
Dave Chinnera5491e02010-10-21 11:49:26 +110067 inode->i_data.backing_dev_info = dst;
Jan Karaa5faeaf2013-06-28 16:04:02 +020068 if (inode->i_state & I_DIRTY) {
69 if (bdi_cap_writeback_dirty(dst) && !wb_has_dirty_io(&dst->wb))
70 wakeup_bdi = true;
Nick Piggin7ccf19a2010-10-21 11:49:30 +110071 list_move(&inode->i_wb_list, &dst->wb.b_dirty);
Jan Karaa5faeaf2013-06-28 16:04:02 +020072 }
Dave Chinner250df6e2011-03-22 22:23:36 +110073 spin_unlock(&inode->i_lock);
Christoph Hellwigf758eea2011-04-21 18:19:44 -060074 spin_unlock(&old->wb.list_lock);
75 spin_unlock(&dst->wb.list_lock);
Jan Karaa5faeaf2013-06-28 16:04:02 +020076
77 if (wakeup_bdi)
78 bdi_wakeup_thread_delayed(dst);
Dave Chinnera5491e02010-10-21 11:49:26 +110079}
80
Peter Zijlstraf9a14392007-05-06 14:49:55 -070081/* Kill _all_ buffers and pagecache , dirty or not.. */
Al Viroff01bb42011-09-16 02:31:11 -040082void kill_bdev(struct block_device *bdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -070083{
Al Viroff01bb42011-09-16 02:31:11 -040084 struct address_space *mapping = bdev->bd_inode->i_mapping;
85
Johannes Weiner91b0abe2014-04-03 14:47:49 -070086 if (mapping->nrpages == 0 && mapping->nrshadows == 0)
Peter Zijlstraf9a14392007-05-06 14:49:55 -070087 return;
Al Viroff01bb42011-09-16 02:31:11 -040088
Peter Zijlstraf9a14392007-05-06 14:49:55 -070089 invalidate_bh_lrus();
Al Viroff01bb42011-09-16 02:31:11 -040090 truncate_inode_pages(mapping, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -070091}
Al Viroff01bb42011-09-16 02:31:11 -040092EXPORT_SYMBOL(kill_bdev);
93
94/* Invalidate clean unused buffers and pagecache. */
95void invalidate_bdev(struct block_device *bdev)
96{
97 struct address_space *mapping = bdev->bd_inode->i_mapping;
98
99 if (mapping->nrpages == 0)
100 return;
101
102 invalidate_bh_lrus();
103 lru_add_drain_all(); /* make sure all lru add caches are flushed */
104 invalidate_mapping_pages(mapping, 0, -1);
105 /* 99% of the time, we don't need to flush the cleancache on the bdev.
106 * But, for the strange corners, lets be cautious
107 */
Dan Magenheimer31677602011-09-21 11:56:28 -0400108 cleancache_invalidate_inode(mapping);
Al Viroff01bb42011-09-16 02:31:11 -0400109}
110EXPORT_SYMBOL(invalidate_bdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111
112int set_blocksize(struct block_device *bdev, int size)
113{
114 /* Size must be a power of two, and between 512 and PAGE_SIZE */
Vignesh Babu BM1368c4f2007-05-08 00:24:32 -0700115 if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 return -EINVAL;
117
118 /* Size cannot be smaller than the size supported by the device */
Martin K. Petersene1defc42009-05-22 17:17:49 -0400119 if (size < bdev_logical_block_size(bdev))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 return -EINVAL;
121
122 /* Don't change the size if it is same as current */
123 if (bdev->bd_block_size != size) {
124 sync_blockdev(bdev);
125 bdev->bd_block_size = size;
126 bdev->bd_inode->i_blkbits = blksize_bits(size);
127 kill_bdev(bdev);
128 }
129 return 0;
130}
131
132EXPORT_SYMBOL(set_blocksize);
133
134int sb_set_blocksize(struct super_block *sb, int size)
135{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 if (set_blocksize(sb->s_bdev, size))
137 return 0;
138 /* If we get here, we know size is power of two
139 * and it's value is between 512 and PAGE_SIZE */
140 sb->s_blocksize = size;
Coywolf Qi Hunt38885bd2006-03-24 03:18:05 -0800141 sb->s_blocksize_bits = blksize_bits(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 return sb->s_blocksize;
143}
144
145EXPORT_SYMBOL(sb_set_blocksize);
146
147int sb_min_blocksize(struct super_block *sb, int size)
148{
Martin K. Petersene1defc42009-05-22 17:17:49 -0400149 int minsize = bdev_logical_block_size(sb->s_bdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 if (size < minsize)
151 size = minsize;
152 return sb_set_blocksize(sb, size);
153}
154
155EXPORT_SYMBOL(sb_min_blocksize);
156
157static int
158blkdev_get_block(struct inode *inode, sector_t iblock,
159 struct buffer_head *bh, int create)
160{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 bh->b_bdev = I_BDEV(inode);
162 bh->b_blocknr = iblock;
163 set_buffer_mapped(bh);
164 return 0;
165}
166
Andrew Mortonb2e895d2007-02-03 01:14:01 -0800167static ssize_t
168blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
169 loff_t offset, unsigned long nr_segs)
170{
171 struct file *file = iocb->ki_filp;
172 struct inode *inode = file->f_mapping->host;
173
Christoph Hellwigeafdc7d2010-06-04 11:29:53 +0200174 return __blockdev_direct_IO(rw, iocb, inode, I_BDEV(inode), iov, offset,
Linus Torvaldsbbec02702012-11-29 12:31:52 -0800175 nr_segs, blkdev_get_block, NULL, NULL, 0);
Andrew Mortonb2e895d2007-02-03 01:14:01 -0800176}
177
Jan Kara5cee5812009-04-27 16:43:51 +0200178int __sync_blockdev(struct block_device *bdev, int wait)
179{
180 if (!bdev)
181 return 0;
182 if (!wait)
183 return filemap_flush(bdev->bd_inode->i_mapping);
184 return filemap_write_and_wait(bdev->bd_inode->i_mapping);
185}
186
Nick Piggin585d3bc2009-02-25 10:44:19 +0100187/*
188 * Write out and wait upon all the dirty data associated with a block
189 * device via its mapping. Does not take the superblock lock.
190 */
191int sync_blockdev(struct block_device *bdev)
192{
Jan Kara5cee5812009-04-27 16:43:51 +0200193 return __sync_blockdev(bdev, 1);
Nick Piggin585d3bc2009-02-25 10:44:19 +0100194}
195EXPORT_SYMBOL(sync_blockdev);
196
197/*
198 * Write out and wait upon all dirty data associated with this
199 * device. Filesystem data as well as the underlying block
200 * device. Takes the superblock lock.
201 */
202int fsync_bdev(struct block_device *bdev)
203{
204 struct super_block *sb = get_super(bdev);
205 if (sb) {
Jan Kara60b06802009-04-27 16:43:53 +0200206 int res = sync_filesystem(sb);
Nick Piggin585d3bc2009-02-25 10:44:19 +0100207 drop_super(sb);
208 return res;
209 }
210 return sync_blockdev(bdev);
211}
Al Viro47e44912009-04-01 07:07:16 -0400212EXPORT_SYMBOL(fsync_bdev);
Nick Piggin585d3bc2009-02-25 10:44:19 +0100213
214/**
215 * freeze_bdev -- lock a filesystem and force it into a consistent state
216 * @bdev: blockdevice to lock
217 *
Nick Piggin585d3bc2009-02-25 10:44:19 +0100218 * If a superblock is found on this device, we take the s_umount semaphore
219 * on it to make sure nobody unmounts until the snapshot creation is done.
220 * The reference counter (bd_fsfreeze_count) guarantees that only the last
221 * unfreeze process can unfreeze the frozen filesystem actually when multiple
222 * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
223 * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
224 * actually.
225 */
226struct super_block *freeze_bdev(struct block_device *bdev)
227{
228 struct super_block *sb;
229 int error = 0;
230
231 mutex_lock(&bdev->bd_fsfreeze_mutex);
Christoph Hellwig45042302009-08-03 23:28:35 +0200232 if (++bdev->bd_fsfreeze_count > 1) {
233 /*
234 * We don't even need to grab a reference - the first call
235 * to freeze_bdev grab an active reference and only the last
236 * thaw_bdev drops it.
237 */
Nick Piggin585d3bc2009-02-25 10:44:19 +0100238 sb = get_super(bdev);
Christoph Hellwig45042302009-08-03 23:28:35 +0200239 drop_super(sb);
Nick Piggin585d3bc2009-02-25 10:44:19 +0100240 mutex_unlock(&bdev->bd_fsfreeze_mutex);
241 return sb;
242 }
Nick Piggin585d3bc2009-02-25 10:44:19 +0100243
Christoph Hellwig45042302009-08-03 23:28:35 +0200244 sb = get_active_super(bdev);
245 if (!sb)
246 goto out;
Josef Bacik18e9e512010-03-23 10:34:56 -0400247 error = freeze_super(sb);
248 if (error) {
249 deactivate_super(sb);
250 bdev->bd_fsfreeze_count--;
Christoph Hellwig45042302009-08-03 23:28:35 +0200251 mutex_unlock(&bdev->bd_fsfreeze_mutex);
Josef Bacik18e9e512010-03-23 10:34:56 -0400252 return ERR_PTR(error);
Nick Piggin585d3bc2009-02-25 10:44:19 +0100253 }
Josef Bacik18e9e512010-03-23 10:34:56 -0400254 deactivate_super(sb);
Christoph Hellwig45042302009-08-03 23:28:35 +0200255 out:
Nick Piggin585d3bc2009-02-25 10:44:19 +0100256 sync_blockdev(bdev);
257 mutex_unlock(&bdev->bd_fsfreeze_mutex);
Christoph Hellwig4fadd7b2009-08-03 23:28:06 +0200258 return sb; /* thaw_bdev releases s->s_umount */
Nick Piggin585d3bc2009-02-25 10:44:19 +0100259}
260EXPORT_SYMBOL(freeze_bdev);
261
262/**
263 * thaw_bdev -- unlock filesystem
264 * @bdev: blockdevice to unlock
265 * @sb: associated superblock
266 *
267 * Unlocks the filesystem and marks it writeable again after freeze_bdev().
268 */
269int thaw_bdev(struct block_device *bdev, struct super_block *sb)
270{
Christoph Hellwig45042302009-08-03 23:28:35 +0200271 int error = -EINVAL;
Nick Piggin585d3bc2009-02-25 10:44:19 +0100272
273 mutex_lock(&bdev->bd_fsfreeze_mutex);
Christoph Hellwig45042302009-08-03 23:28:35 +0200274 if (!bdev->bd_fsfreeze_count)
Josef Bacik18e9e512010-03-23 10:34:56 -0400275 goto out;
Nick Piggin585d3bc2009-02-25 10:44:19 +0100276
Christoph Hellwig45042302009-08-03 23:28:35 +0200277 error = 0;
278 if (--bdev->bd_fsfreeze_count > 0)
Josef Bacik18e9e512010-03-23 10:34:56 -0400279 goto out;
Nick Piggin585d3bc2009-02-25 10:44:19 +0100280
Christoph Hellwig45042302009-08-03 23:28:35 +0200281 if (!sb)
Josef Bacik18e9e512010-03-23 10:34:56 -0400282 goto out;
Christoph Hellwig45042302009-08-03 23:28:35 +0200283
Josef Bacik18e9e512010-03-23 10:34:56 -0400284 error = thaw_super(sb);
285 if (error) {
286 bdev->bd_fsfreeze_count++;
287 mutex_unlock(&bdev->bd_fsfreeze_mutex);
288 return error;
Nick Piggin585d3bc2009-02-25 10:44:19 +0100289 }
Josef Bacik18e9e512010-03-23 10:34:56 -0400290out:
Nick Piggin585d3bc2009-02-25 10:44:19 +0100291 mutex_unlock(&bdev->bd_fsfreeze_mutex);
292 return 0;
293}
294EXPORT_SYMBOL(thaw_bdev);
295
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
297{
298 return block_write_full_page(page, blkdev_get_block, wbc);
299}
300
301static int blkdev_readpage(struct file * file, struct page * page)
302{
303 return block_read_full_page(page, blkdev_get_block);
304}
305
Nick Piggin6272b5a2007-10-16 01:25:04 -0700306static int blkdev_write_begin(struct file *file, struct address_space *mapping,
307 loff_t pos, unsigned len, unsigned flags,
308 struct page **pagep, void **fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309{
Christoph Hellwig155130a2010-06-04 11:29:58 +0200310 return block_write_begin(mapping, pos, len, flags, pagep,
311 blkdev_get_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312}
313
Nick Piggin6272b5a2007-10-16 01:25:04 -0700314static int blkdev_write_end(struct file *file, struct address_space *mapping,
315 loff_t pos, unsigned len, unsigned copied,
316 struct page *page, void *fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317{
Nick Piggin6272b5a2007-10-16 01:25:04 -0700318 int ret;
319 ret = block_write_end(file, mapping, pos, len, copied, page, fsdata);
320
321 unlock_page(page);
322 page_cache_release(page);
323
324 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325}
326
327/*
328 * private llseek:
Al Viro496ad9a2013-01-23 17:07:38 -0500329 * for a block special file file_inode(file)->i_size is zero
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 * so we compute the size by hand (just as in block_read/write above)
331 */
Andrew Morton965c8e52012-12-17 15:59:39 -0800332static loff_t block_llseek(struct file *file, loff_t offset, int whence)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333{
334 struct inode *bd_inode = file->f_mapping->host;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 loff_t retval;
336
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800337 mutex_lock(&bd_inode->i_mutex);
Al Viro5d48f3a2013-06-23 21:34:45 +0400338 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800339 mutex_unlock(&bd_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 return retval;
341}
342
Josef Bacik02c24a82011-07-16 20:44:56 -0400343int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344{
Anton Blanchardb8af67e2010-04-23 13:18:06 -0400345 struct inode *bd_inode = filp->f_mapping->host;
346 struct block_device *bdev = I_BDEV(bd_inode);
Christoph Hellwigab0a9732009-10-29 14:14:04 +0100347 int error;
Rafael J. Wysockida5aa862011-08-02 02:17:48 +0200348
349 error = filemap_write_and_wait_range(filp->f_mapping, start, end);
350 if (error)
351 return error;
Christoph Hellwigab0a9732009-10-29 14:14:04 +0100352
Anton Blanchardb8af67e2010-04-23 13:18:06 -0400353 /*
354 * There is no need to serialise calls to blkdev_issue_flush with
355 * i_mutex and doing so causes performance issues with concurrent
356 * O_SYNC writers to a block device.
357 */
Christoph Hellwigdd3932e2010-09-16 20:51:46 +0200358 error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL);
Christoph Hellwigab0a9732009-10-29 14:14:04 +0100359 if (error == -EOPNOTSUPP)
360 error = 0;
Anton Blanchardb8af67e2010-04-23 13:18:06 -0400361
Christoph Hellwigab0a9732009-10-29 14:14:04 +0100362 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363}
Andrew Mortonb1dd3b22010-04-06 14:35:00 -0700364EXPORT_SYMBOL(blkdev_fsync);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365
366/*
367 * pseudo-fs
368 */
369
370static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
Christoph Lametere18b8902006-12-06 20:33:20 -0800371static struct kmem_cache * bdev_cachep __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372
373static struct inode *bdev_alloc_inode(struct super_block *sb)
374{
Christoph Lametere94b1762006-12-06 20:33:17 -0800375 struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376 if (!ei)
377 return NULL;
378 return &ei->vfs_inode;
379}
380
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +1100381static void bdev_i_callback(struct rcu_head *head)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382{
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +1100383 struct inode *inode = container_of(head, struct inode, i_rcu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 struct bdev_inode *bdi = BDEV_I(inode);
385
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 kmem_cache_free(bdev_cachep, bdi);
387}
388
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +1100389static void bdev_destroy_inode(struct inode *inode)
390{
391 call_rcu(&inode->i_rcu, bdev_i_callback);
392}
393
Alexey Dobriyan51cc5062008-07-25 19:45:34 -0700394static void init_once(void *foo)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395{
396 struct bdev_inode *ei = (struct bdev_inode *) foo;
397 struct block_device *bdev = &ei->bdev;
398
Christoph Lametera35afb82007-05-16 22:10:57 -0700399 memset(bdev, 0, sizeof(*bdev));
400 mutex_init(&bdev->bd_mutex);
Christoph Lametera35afb82007-05-16 22:10:57 -0700401 INIT_LIST_HEAD(&bdev->bd_inodes);
402 INIT_LIST_HEAD(&bdev->bd_list);
Tejun Heo49731ba2011-01-14 18:43:57 +0100403#ifdef CONFIG_SYSFS
404 INIT_LIST_HEAD(&bdev->bd_holder_disks);
405#endif
Christoph Lametera35afb82007-05-16 22:10:57 -0700406 inode_init_once(&ei->vfs_inode);
Takashi Satofcccf502009-01-09 16:40:59 -0800407 /* Initialize mutex for freeze. */
408 mutex_init(&bdev->bd_fsfreeze_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409}
410
411static inline void __bd_forget(struct inode *inode)
412{
413 list_del_init(&inode->i_devices);
414 inode->i_bdev = NULL;
415 inode->i_mapping = &inode->i_data;
416}
417
Al Virob57922d2010-06-07 14:34:48 -0400418static void bdev_evict_inode(struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419{
420 struct block_device *bdev = &BDEV_I(inode)->bdev;
421 struct list_head *p;
Johannes Weiner91b0abe2014-04-03 14:47:49 -0700422 truncate_inode_pages_final(&inode->i_data);
Al Virob57922d2010-06-07 14:34:48 -0400423 invalidate_inode_buffers(inode); /* is it needed here? */
Jan Karadbd57682012-05-03 14:48:02 +0200424 clear_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 spin_lock(&bdev_lock);
426 while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) {
427 __bd_forget(list_entry(p, struct inode, i_devices));
428 }
429 list_del_init(&bdev->bd_list);
430 spin_unlock(&bdev_lock);
431}
432
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800433static const struct super_operations bdev_sops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 .statfs = simple_statfs,
435 .alloc_inode = bdev_alloc_inode,
436 .destroy_inode = bdev_destroy_inode,
437 .drop_inode = generic_delete_inode,
Al Virob57922d2010-06-07 14:34:48 -0400438 .evict_inode = bdev_evict_inode,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439};
440
Al Viro51139ad2010-07-25 23:47:46 +0400441static struct dentry *bd_mount(struct file_system_type *fs_type,
442 int flags, const char *dev_name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443{
Muthu Kumarb502bd12012-03-23 15:01:50 -0700444 return mount_pseudo(fs_type, "bdev:", &bdev_sops, NULL, BDEVFS_MAGIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445}
446
447static struct file_system_type bd_type = {
448 .name = "bdev",
Al Viro51139ad2010-07-25 23:47:46 +0400449 .mount = bd_mount,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 .kill_sb = kill_anon_super,
451};
452
Al Virof47ec3f2011-11-21 21:15:42 -0500453static struct super_block *blockdev_superblock __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454
455void __init bdev_cache_init(void)
456{
457 int err;
Sergey Senozhatskyace85772012-01-10 02:43:59 +0300458 static struct vfsmount *bd_mnt;
Denis ChengRqc2acf7b2008-12-01 14:34:56 -0800459
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460 bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
Paul Jacksonfffb60f2006-03-24 03:16:06 -0800461 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
462 SLAB_MEM_SPREAD|SLAB_PANIC),
Paul Mundt20c2df82007-07-20 10:11:58 +0900463 init_once);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 err = register_filesystem(&bd_type);
465 if (err)
466 panic("Cannot register bdev pseudo-fs");
467 bd_mnt = kern_mount(&bd_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 if (IS_ERR(bd_mnt))
469 panic("Cannot create bdev pseudo-fs");
Sergey Senozhatskyace85772012-01-10 02:43:59 +0300470 blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471}
472
473/*
474 * Most likely _very_ bad one - but then it's hardly critical for small
475 * /dev and can be fixed when somebody will need really large one.
476 * Keep in mind that it will be fed through icache hash function too.
477 */
478static inline unsigned long hash(dev_t dev)
479{
480 return MAJOR(dev)+MINOR(dev);
481}
482
483static int bdev_test(struct inode *inode, void *data)
484{
485 return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data;
486}
487
488static int bdev_set(struct inode *inode, void *data)
489{
490 BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data;
491 return 0;
492}
493
494static LIST_HEAD(all_bdevs);
495
496struct block_device *bdget(dev_t dev)
497{
498 struct block_device *bdev;
499 struct inode *inode;
500
Denis ChengRqc2acf7b2008-12-01 14:34:56 -0800501 inode = iget5_locked(blockdev_superblock, hash(dev),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 bdev_test, bdev_set, &dev);
503
504 if (!inode)
505 return NULL;
506
507 bdev = &BDEV_I(inode)->bdev;
508
509 if (inode->i_state & I_NEW) {
510 bdev->bd_contains = NULL;
Lachlan McIlroy782b94c2011-06-30 11:01:45 +1000511 bdev->bd_super = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 bdev->bd_inode = inode;
513 bdev->bd_block_size = (1 << inode->i_blkbits);
514 bdev->bd_part_count = 0;
515 bdev->bd_invalidated = 0;
516 inode->i_mode = S_IFBLK;
517 inode->i_rdev = dev;
518 inode->i_bdev = bdev;
519 inode->i_data.a_ops = &def_blk_aops;
520 mapping_set_gfp_mask(&inode->i_data, GFP_USER);
521 inode->i_data.backing_dev_info = &default_backing_dev_info;
522 spin_lock(&bdev_lock);
523 list_add(&bdev->bd_list, &all_bdevs);
524 spin_unlock(&bdev_lock);
525 unlock_new_inode(inode);
526 }
527 return bdev;
528}
529
530EXPORT_SYMBOL(bdget);
531
Alan Jenkinsdddac6a2009-07-29 21:07:55 +0200532/**
533 * bdgrab -- Grab a reference to an already referenced block device
534 * @bdev: Block device to grab a reference to.
535 */
536struct block_device *bdgrab(struct block_device *bdev)
537{
Al Viro7de9c6ee2010-10-23 11:11:40 -0400538 ihold(bdev->bd_inode);
Alan Jenkinsdddac6a2009-07-29 21:07:55 +0200539 return bdev;
540}
Anatol Pomozovc1681bf2013-04-01 09:47:56 -0700541EXPORT_SYMBOL(bdgrab);
Alan Jenkinsdddac6a2009-07-29 21:07:55 +0200542
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543long nr_blockdev_pages(void)
544{
Matthias Kaehlcke203a2932007-07-15 23:40:23 -0700545 struct block_device *bdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 long ret = 0;
547 spin_lock(&bdev_lock);
Matthias Kaehlcke203a2932007-07-15 23:40:23 -0700548 list_for_each_entry(bdev, &all_bdevs, bd_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 ret += bdev->bd_inode->i_mapping->nrpages;
550 }
551 spin_unlock(&bdev_lock);
552 return ret;
553}
554
555void bdput(struct block_device *bdev)
556{
557 iput(bdev->bd_inode);
558}
559
560EXPORT_SYMBOL(bdput);
561
562static struct block_device *bd_acquire(struct inode *inode)
563{
564 struct block_device *bdev;
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700565
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 spin_lock(&bdev_lock);
567 bdev = inode->i_bdev;
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700568 if (bdev) {
Al Viro7de9c6ee2010-10-23 11:11:40 -0400569 ihold(bdev->bd_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 spin_unlock(&bdev_lock);
571 return bdev;
572 }
573 spin_unlock(&bdev_lock);
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700574
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 bdev = bdget(inode->i_rdev);
576 if (bdev) {
577 spin_lock(&bdev_lock);
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700578 if (!inode->i_bdev) {
579 /*
Al Viro7de9c6ee2010-10-23 11:11:40 -0400580 * We take an additional reference to bd_inode,
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700581 * and it's released in clear_inode() of inode.
582 * So, we can access it via ->i_mapping always
583 * without igrab().
584 */
Al Viro7de9c6ee2010-10-23 11:11:40 -0400585 ihold(bdev->bd_inode);
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700586 inode->i_bdev = bdev;
587 inode->i_mapping = bdev->bd_inode->i_mapping;
588 list_add(&inode->i_devices, &bdev->bd_inodes);
589 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 spin_unlock(&bdev_lock);
591 }
592 return bdev;
593}
594
Jan Karaa8855992013-07-09 22:36:45 +0800595int sb_is_blkdev_sb(struct super_block *sb)
Al Virof47ec3f2011-11-21 21:15:42 -0500596{
597 return sb == blockdev_superblock;
598}
599
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600/* Call when you free inode */
601
602void bd_forget(struct inode *inode)
603{
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700604 struct block_device *bdev = NULL;
605
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 spin_lock(&bdev_lock);
Yan Hongb4ea2ea2013-04-30 15:26:47 -0700607 if (!sb_is_blkdev_sb(inode->i_sb))
608 bdev = inode->i_bdev;
609 __bd_forget(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 spin_unlock(&bdev_lock);
OGAWA Hirofumi09d967c2006-06-22 14:47:21 -0700611
612 if (bdev)
613 iput(bdev->bd_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614}
615
Tejun Heo1a3cbbc2010-04-07 18:52:29 +0900616/**
617 * bd_may_claim - test whether a block device can be claimed
618 * @bdev: block device of interest
619 * @whole: whole block device containing @bdev, may equal @bdev
620 * @holder: holder trying to claim @bdev
621 *
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300622 * Test whether @bdev can be claimed by @holder.
Tejun Heo1a3cbbc2010-04-07 18:52:29 +0900623 *
624 * CONTEXT:
625 * spin_lock(&bdev_lock).
626 *
627 * RETURNS:
628 * %true if @bdev can be claimed, %false otherwise.
629 */
630static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
631 void *holder)
632{
633 if (bdev->bd_holder == holder)
634 return true; /* already a holder */
635 else if (bdev->bd_holder != NULL)
636 return false; /* held by someone else */
637 else if (bdev->bd_contains == bdev)
638 return true; /* is a whole device which isn't held */
639
Tejun Heoe525fd82010-11-13 11:55:17 +0100640 else if (whole->bd_holder == bd_may_claim)
Tejun Heo1a3cbbc2010-04-07 18:52:29 +0900641 return true; /* is a partition of a device that is being partitioned */
642 else if (whole->bd_holder != NULL)
643 return false; /* is a partition of a held device */
644 else
645 return true; /* is a partition of an un-held device */
646}
647
648/**
Tejun Heo6b4517a2010-04-07 18:53:59 +0900649 * bd_prepare_to_claim - prepare to claim a block device
650 * @bdev: block device of interest
651 * @whole: the whole device containing @bdev, may equal @bdev
652 * @holder: holder trying to claim @bdev
653 *
654 * Prepare to claim @bdev. This function fails if @bdev is already
655 * claimed by another holder and waits if another claiming is in
656 * progress. This function doesn't actually claim. On successful
657 * return, the caller has ownership of bd_claiming and bd_holder[s].
658 *
659 * CONTEXT:
660 * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab
661 * it multiple times.
662 *
663 * RETURNS:
664 * 0 if @bdev can be claimed, -EBUSY otherwise.
665 */
666static int bd_prepare_to_claim(struct block_device *bdev,
667 struct block_device *whole, void *holder)
668{
669retry:
670 /* if someone else claimed, fail */
671 if (!bd_may_claim(bdev, whole, holder))
672 return -EBUSY;
673
Tejun Heoe75aa852010-08-04 17:59:39 +0200674 /* if claiming is already in progress, wait for it to finish */
675 if (whole->bd_claiming) {
Tejun Heo6b4517a2010-04-07 18:53:59 +0900676 wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0);
677 DEFINE_WAIT(wait);
678
679 prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
680 spin_unlock(&bdev_lock);
681 schedule();
682 finish_wait(wq, &wait);
683 spin_lock(&bdev_lock);
684 goto retry;
685 }
686
687 /* yay, all mine */
688 return 0;
689}
690
691/**
692 * bd_start_claiming - start claiming a block device
693 * @bdev: block device of interest
694 * @holder: holder trying to claim @bdev
695 *
696 * @bdev is about to be opened exclusively. Check @bdev can be opened
697 * exclusively and mark that an exclusive open is in progress. Each
698 * successful call to this function must be matched with a call to
Nick Pigginb0018362010-05-26 01:51:19 +1000699 * either bd_finish_claiming() or bd_abort_claiming() (which do not
700 * fail).
701 *
702 * This function is used to gain exclusive access to the block device
703 * without actually causing other exclusive open attempts to fail. It
704 * should be used when the open sequence itself requires exclusive
705 * access but may subsequently fail.
Tejun Heo6b4517a2010-04-07 18:53:59 +0900706 *
707 * CONTEXT:
708 * Might sleep.
709 *
710 * RETURNS:
711 * Pointer to the block device containing @bdev on success, ERR_PTR()
712 * value on failure.
713 */
714static struct block_device *bd_start_claiming(struct block_device *bdev,
715 void *holder)
716{
717 struct gendisk *disk;
718 struct block_device *whole;
719 int partno, err;
720
721 might_sleep();
722
723 /*
724 * @bdev might not have been initialized properly yet, look up
725 * and grab the outer block device the hard way.
726 */
727 disk = get_gendisk(bdev->bd_dev, &partno);
728 if (!disk)
729 return ERR_PTR(-ENXIO);
730
Tejun Heod4c208b2011-06-13 12:45:48 +0200731 /*
732 * Normally, @bdev should equal what's returned from bdget_disk()
733 * if partno is 0; however, some drivers (floppy) use multiple
734 * bdev's for the same physical device and @bdev may be one of the
735 * aliases. Keep @bdev if partno is 0. This means claimer
736 * tracking is broken for those devices but it has always been that
737 * way.
738 */
739 if (partno)
740 whole = bdget_disk(disk, 0);
741 else
742 whole = bdgrab(bdev);
743
Nick Piggincf342572010-05-26 01:50:21 +1000744 module_put(disk->fops->owner);
Tejun Heo6b4517a2010-04-07 18:53:59 +0900745 put_disk(disk);
746 if (!whole)
747 return ERR_PTR(-ENOMEM);
748
749 /* prepare to claim, if successful, mark claiming in progress */
750 spin_lock(&bdev_lock);
751
752 err = bd_prepare_to_claim(bdev, whole, holder);
753 if (err == 0) {
754 whole->bd_claiming = holder;
755 spin_unlock(&bdev_lock);
756 return whole;
757 } else {
758 spin_unlock(&bdev_lock);
759 bdput(whole);
760 return ERR_PTR(err);
761 }
762}
763
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800764#ifdef CONFIG_SYSFS
Tejun Heo49731ba2011-01-14 18:43:57 +0100765struct bd_holder_disk {
766 struct list_head list;
767 struct gendisk *disk;
768 int refcnt;
769};
770
771static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev,
772 struct gendisk *disk)
773{
774 struct bd_holder_disk *holder;
775
776 list_for_each_entry(holder, &bdev->bd_holder_disks, list)
777 if (holder->disk == disk)
778 return holder;
779 return NULL;
780}
781
Andrew Morton4d7dd8fd2006-09-29 01:58:56 -0700782static int add_symlink(struct kobject *from, struct kobject *to)
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800783{
Andrew Morton4d7dd8fd2006-09-29 01:58:56 -0700784 return sysfs_create_link(from, to, kobject_name(to));
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800785}
786
787static void del_symlink(struct kobject *from, struct kobject *to)
788{
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800789 sysfs_remove_link(from, kobject_name(to));
790}
791
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800792/**
Tejun Heoe09b4572010-11-13 11:55:17 +0100793 * bd_link_disk_holder - create symlinks between holding disk and slave bdev
794 * @bdev: the claimed slave bdev
795 * @disk: the holding disk
Jun'ichi Nomuradf6c0cd2006-10-30 16:23:56 -0500796 *
Tejun Heo49731ba2011-01-14 18:43:57 +0100797 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
798 *
Tejun Heoe09b4572010-11-13 11:55:17 +0100799 * This functions creates the following sysfs symlinks.
Jun'ichi Nomuradf6c0cd2006-10-30 16:23:56 -0500800 *
Tejun Heoe09b4572010-11-13 11:55:17 +0100801 * - from "slaves" directory of the holder @disk to the claimed @bdev
802 * - from "holders" directory of the @bdev to the holder @disk
803 *
804 * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
805 * passed to bd_link_disk_holder(), then:
806 *
807 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
808 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
809 *
810 * The caller must have claimed @bdev before calling this function and
811 * ensure that both @bdev and @disk are valid during the creation and
812 * lifetime of these symlinks.
813 *
814 * CONTEXT:
815 * Might sleep.
816 *
817 * RETURNS:
818 * 0 on success, -errno on failure.
Jun'ichi Nomuradf6c0cd2006-10-30 16:23:56 -0500819 */
Tejun Heoe09b4572010-11-13 11:55:17 +0100820int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
Jun'ichi Nomuradf6c0cd2006-10-30 16:23:56 -0500821{
Tejun Heo49731ba2011-01-14 18:43:57 +0100822 struct bd_holder_disk *holder;
Tejun Heoe09b4572010-11-13 11:55:17 +0100823 int ret = 0;
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800824
Peter Zijlstra2e7b6512006-12-08 02:36:13 -0800825 mutex_lock(&bdev->bd_mutex);
Jun'ichi Nomuradf6c0cd2006-10-30 16:23:56 -0500826
Tejun Heo49731ba2011-01-14 18:43:57 +0100827 WARN_ON_ONCE(!bdev->bd_holder);
Johannes Weiner4e916722007-07-15 23:41:25 -0700828
Tejun Heoe09b4572010-11-13 11:55:17 +0100829 /* FIXME: remove the following once add_disk() handles errors */
830 if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir))
831 goto out_unlock;
Johannes Weiner4e916722007-07-15 23:41:25 -0700832
Tejun Heo49731ba2011-01-14 18:43:57 +0100833 holder = bd_find_holder_disk(bdev, disk);
834 if (holder) {
835 holder->refcnt++;
Tejun Heoe09b4572010-11-13 11:55:17 +0100836 goto out_unlock;
837 }
838
Tejun Heo49731ba2011-01-14 18:43:57 +0100839 holder = kzalloc(sizeof(*holder), GFP_KERNEL);
840 if (!holder) {
841 ret = -ENOMEM;
842 goto out_unlock;
843 }
844
845 INIT_LIST_HEAD(&holder->list);
846 holder->disk = disk;
847 holder->refcnt = 1;
848
849 ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
850 if (ret)
851 goto out_free;
852
853 ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj);
854 if (ret)
855 goto out_del;
Tejun Heoe7407d12011-02-24 09:56:32 +0100856 /*
857 * bdev could be deleted beneath us which would implicitly destroy
858 * the holder directory. Hold on to it.
859 */
860 kobject_get(bdev->bd_part->holder_dir);
Tejun Heo49731ba2011-01-14 18:43:57 +0100861
862 list_add(&holder->list, &bdev->bd_holder_disks);
863 goto out_unlock;
864
865out_del:
866 del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
867out_free:
868 kfree(holder);
Tejun Heoe09b4572010-11-13 11:55:17 +0100869out_unlock:
Jun'ichi Nomurab4cf1b72006-03-27 01:18:00 -0800870 mutex_unlock(&bdev->bd_mutex);
Tejun Heoe09b4572010-11-13 11:55:17 +0100871 return ret;
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800872}
Tejun Heoe09b4572010-11-13 11:55:17 +0100873EXPORT_SYMBOL_GPL(bd_link_disk_holder);
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800874
Tejun Heo49731ba2011-01-14 18:43:57 +0100875/**
876 * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
877 * @bdev: the calimed slave bdev
878 * @disk: the holding disk
879 *
880 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
881 *
882 * CONTEXT:
883 * Might sleep.
884 */
885void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800886{
Tejun Heo49731ba2011-01-14 18:43:57 +0100887 struct bd_holder_disk *holder;
Tejun Heoe09b4572010-11-13 11:55:17 +0100888
Tejun Heo49731ba2011-01-14 18:43:57 +0100889 mutex_lock(&bdev->bd_mutex);
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800890
Tejun Heo49731ba2011-01-14 18:43:57 +0100891 holder = bd_find_holder_disk(bdev, disk);
892
893 if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) {
894 del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
895 del_symlink(bdev->bd_part->holder_dir,
896 &disk_to_dev(disk)->kobj);
Tejun Heoe7407d12011-02-24 09:56:32 +0100897 kobject_put(bdev->bd_part->holder_dir);
Tejun Heo49731ba2011-01-14 18:43:57 +0100898 list_del_init(&holder->list);
899 kfree(holder);
900 }
901
902 mutex_unlock(&bdev->bd_mutex);
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800903}
Tejun Heo49731ba2011-01-14 18:43:57 +0100904EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
Jun'ichi Nomura641dc632006-03-27 01:17:57 -0800905#endif
906
Andrew Patterson0c002c22008-09-04 14:27:20 -0600907/**
Andrew Patterson56ade442008-09-04 14:27:40 -0600908 * flush_disk - invalidates all buffer-cache entries on a disk
909 *
910 * @bdev: struct block device to be flushed
Randy Dunlape6eb5ce2011-02-26 10:54:00 -0800911 * @kill_dirty: flag to guide handling of dirty inodes
Andrew Patterson56ade442008-09-04 14:27:40 -0600912 *
913 * Invalidates all buffer-cache entries on a disk. It should be called
914 * when a disk has been changed -- either by a media change or online
915 * resize.
916 */
NeilBrown93b270f2011-02-24 17:25:47 +1100917static void flush_disk(struct block_device *bdev, bool kill_dirty)
Andrew Patterson56ade442008-09-04 14:27:40 -0600918{
NeilBrown93b270f2011-02-24 17:25:47 +1100919 if (__invalidate_device(bdev, kill_dirty)) {
Andrew Patterson56ade442008-09-04 14:27:40 -0600920 char name[BDEVNAME_SIZE] = "";
921
922 if (bdev->bd_disk)
923 disk_name(bdev->bd_disk, 0, name);
924 printk(KERN_WARNING "VFS: busy inodes on changed media or "
925 "resized disk %s\n", name);
926 }
927
928 if (!bdev->bd_disk)
929 return;
Tejun Heod27769e2011-08-23 20:01:04 +0200930 if (disk_part_scan_enabled(bdev->bd_disk))
Andrew Patterson56ade442008-09-04 14:27:40 -0600931 bdev->bd_invalidated = 1;
932}
933
934/**
Randy Dunlap57d1b532008-10-09 10:42:38 +0200935 * check_disk_size_change - checks for disk size change and adjusts bdev size.
Andrew Pattersonc3279d12008-09-04 14:27:25 -0600936 * @disk: struct gendisk to check
937 * @bdev: struct bdev to adjust.
938 *
939 * This routine checks to see if the bdev size does not match the disk size
940 * and adjusts it if it differs.
941 */
942void check_disk_size_change(struct gendisk *disk, struct block_device *bdev)
943{
944 loff_t disk_size, bdev_size;
945
946 disk_size = (loff_t)get_capacity(disk) << 9;
947 bdev_size = i_size_read(bdev->bd_inode);
948 if (disk_size != bdev_size) {
949 char name[BDEVNAME_SIZE];
950
951 disk_name(disk, 0, name);
952 printk(KERN_INFO
953 "%s: detected capacity change from %lld to %lld\n",
954 name, bdev_size, disk_size);
955 i_size_write(bdev->bd_inode, disk_size);
NeilBrown93b270f2011-02-24 17:25:47 +1100956 flush_disk(bdev, false);
Andrew Pattersonc3279d12008-09-04 14:27:25 -0600957 }
958}
959EXPORT_SYMBOL(check_disk_size_change);
960
961/**
Randy Dunlap57d1b532008-10-09 10:42:38 +0200962 * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
Andrew Patterson0c002c22008-09-04 14:27:20 -0600963 * @disk: struct gendisk to be revalidated
964 *
965 * This routine is a wrapper for lower-level driver's revalidate_disk
966 * call-backs. It is used to do common pre and post operations needed
967 * for all revalidate_disk operations.
968 */
969int revalidate_disk(struct gendisk *disk)
970{
Andrew Pattersonc3279d12008-09-04 14:27:25 -0600971 struct block_device *bdev;
Andrew Patterson0c002c22008-09-04 14:27:20 -0600972 int ret = 0;
973
974 if (disk->fops->revalidate_disk)
975 ret = disk->fops->revalidate_disk(disk);
976
Andrew Pattersonc3279d12008-09-04 14:27:25 -0600977 bdev = bdget_disk(disk, 0);
978 if (!bdev)
979 return ret;
980
981 mutex_lock(&bdev->bd_mutex);
982 check_disk_size_change(disk, bdev);
MITSUNARI Shigeo7630b662013-02-21 16:42:01 -0800983 bdev->bd_invalidated = 0;
Andrew Pattersonc3279d12008-09-04 14:27:25 -0600984 mutex_unlock(&bdev->bd_mutex);
985 bdput(bdev);
Andrew Patterson0c002c22008-09-04 14:27:20 -0600986 return ret;
987}
988EXPORT_SYMBOL(revalidate_disk);
989
Linus Torvalds1da177e2005-04-16 15:20:36 -0700990/*
991 * This routine checks whether a removable media has been changed,
992 * and invalidates all buffer-cache-entries in that case. This
993 * is a relatively slow routine, so we have to try to minimize using
994 * it. Thus it is called only upon a 'mount' or 'open'. This
995 * is the best way of combining speed and utility, I think.
996 * People changing diskettes in the middle of an operation deserve
997 * to lose :-)
998 */
999int check_disk_change(struct block_device *bdev)
1000{
1001 struct gendisk *disk = bdev->bd_disk;
Alexey Dobriyan83d5cde2009-09-21 17:01:13 -07001002 const struct block_device_operations *bdops = disk->fops;
Tejun Heo77ea8872010-12-08 20:57:37 +01001003 unsigned int events;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004
Tejun Heo77ea8872010-12-08 20:57:37 +01001005 events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE |
1006 DISK_EVENT_EJECT_REQUEST);
1007 if (!(events & DISK_EVENT_MEDIA_CHANGE))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001008 return 0;
1009
NeilBrown93b270f2011-02-24 17:25:47 +11001010 flush_disk(bdev, true);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 if (bdops->revalidate_disk)
1012 bdops->revalidate_disk(bdev->bd_disk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013 return 1;
1014}
1015
1016EXPORT_SYMBOL(check_disk_change);
1017
1018void bd_set_size(struct block_device *bdev, loff_t size)
1019{
Martin K. Petersene1defc42009-05-22 17:17:49 -04001020 unsigned bsize = bdev_logical_block_size(bdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021
Guo Chaod646a022013-02-21 15:16:42 -08001022 mutex_lock(&bdev->bd_inode->i_mutex);
1023 i_size_write(bdev->bd_inode, size);
1024 mutex_unlock(&bdev->bd_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025 while (bsize < PAGE_CACHE_SIZE) {
1026 if (size & bsize)
1027 break;
1028 bsize <<= 1;
1029 }
1030 bdev->bd_block_size = bsize;
1031 bdev->bd_inode->i_blkbits = blksize_bits(bsize);
1032}
1033EXPORT_SYMBOL(bd_set_size);
1034
Al Viro4385bab2013-05-05 22:11:03 -04001035static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
NeilBrown37be4122006-12-08 02:36:16 -08001036
Peter Zijlstra6d740cd2007-02-20 13:58:18 -08001037/*
1038 * bd_mutex locking:
1039 *
1040 * mutex_lock(part->bd_mutex)
1041 * mutex_lock_nested(whole->bd_mutex, 1)
1042 */
1043
Al Viro572c4892007-10-08 13:24:05 -04001044static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046 struct gendisk *disk;
Tejun Heo523e1d32011-10-19 14:31:07 +02001047 struct module *owner;
Pavel Emelyanov7db9cfd2008-06-05 22:46:27 -07001048 int ret;
Tejun Heocf771cb2008-09-03 09:01:09 +02001049 int partno;
Al Virofe6e9c12008-06-23 08:30:55 -04001050 int perm = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001051
Al Viro572c4892007-10-08 13:24:05 -04001052 if (mode & FMODE_READ)
Al Virofe6e9c12008-06-23 08:30:55 -04001053 perm |= MAY_READ;
Al Viro572c4892007-10-08 13:24:05 -04001054 if (mode & FMODE_WRITE)
Al Virofe6e9c12008-06-23 08:30:55 -04001055 perm |= MAY_WRITE;
1056 /*
1057 * hooks: /n/, see "layering violations".
1058 */
Chris Wrightb7300b72010-08-10 18:02:55 -07001059 if (!for_part) {
1060 ret = devcgroup_inode_permission(bdev->bd_inode, perm);
1061 if (ret != 0) {
1062 bdput(bdev);
1063 return ret;
1064 }
Al Viro82666022008-08-01 05:32:04 -04001065 }
Pavel Emelyanov7db9cfd2008-06-05 22:46:27 -07001066
NeilBrownd3374822009-01-09 08:31:10 +11001067 restart:
Tejun Heo0762b8b2008-08-25 19:56:12 +09001068
Tejun Heo89f97492008-11-05 10:21:06 +01001069 ret = -ENXIO;
Tejun Heocf771cb2008-09-03 09:01:09 +02001070 disk = get_gendisk(bdev->bd_dev, &partno);
Tejun Heo0762b8b2008-08-25 19:56:12 +09001071 if (!disk)
Arnd Bergmann6e9624b2010-08-07 18:25:34 +02001072 goto out;
Tejun Heo523e1d32011-10-19 14:31:07 +02001073 owner = disk->fops->owner;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074
Tejun Heo69e02c52011-03-09 19:54:27 +01001075 disk_block_events(disk);
NeilBrown6796bf52006-12-08 02:36:16 -08001076 mutex_lock_nested(&bdev->bd_mutex, for_part);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077 if (!bdev->bd_openers) {
1078 bdev->bd_disk = disk;
Andi Kleen87192a22012-01-12 17:20:34 -08001079 bdev->bd_queue = disk->queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080 bdev->bd_contains = bdev;
Tejun Heocf771cb2008-09-03 09:01:09 +02001081 if (!partno) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082 struct backing_dev_info *bdi;
Tejun Heo89f97492008-11-05 10:21:06 +01001083
1084 ret = -ENXIO;
1085 bdev->bd_part = disk_get_part(disk, partno);
1086 if (!bdev->bd_part)
1087 goto out_clear;
1088
Tejun Heo1196f8b2011-04-21 20:54:45 +02001089 ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 if (disk->fops->open) {
Al Viro572c4892007-10-08 13:24:05 -04001091 ret = disk->fops->open(bdev, mode);
NeilBrownd3374822009-01-09 08:31:10 +11001092 if (ret == -ERESTARTSYS) {
1093 /* Lost a race with 'disk' being
1094 * deleted, try again.
1095 * See md.c
1096 */
1097 disk_put_part(bdev->bd_part);
1098 bdev->bd_part = NULL;
NeilBrownd3374822009-01-09 08:31:10 +11001099 bdev->bd_disk = NULL;
Andi Kleen87192a22012-01-12 17:20:34 -08001100 bdev->bd_queue = NULL;
NeilBrownd3374822009-01-09 08:31:10 +11001101 mutex_unlock(&bdev->bd_mutex);
Tejun Heo69e02c52011-03-09 19:54:27 +01001102 disk_unblock_events(disk);
Tejun Heo69e02c52011-03-09 19:54:27 +01001103 put_disk(disk);
Tejun Heo523e1d32011-10-19 14:31:07 +02001104 module_put(owner);
NeilBrownd3374822009-01-09 08:31:10 +11001105 goto restart;
1106 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107 }
Tejun Heo7e697232011-05-23 13:26:07 +02001108
Guo Chaode331272013-02-21 15:16:43 -08001109 if (!ret) {
Tejun Heo7e697232011-05-23 13:26:07 +02001110 bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);
1111 bdi = blk_get_backing_dev_info(bdev);
1112 if (bdi == NULL)
1113 bdi = &default_backing_dev_info;
1114 bdev_inode_switch_bdi(bdev->bd_inode, bdi);
1115 }
1116
Tejun Heo1196f8b2011-04-21 20:54:45 +02001117 /*
1118 * If the device is invalidated, rescan partition
1119 * if open succeeded or failed with -ENOMEDIUM.
1120 * The latter is necessary to prevent ghost
1121 * partitions on a removed medium.
1122 */
Jun'ichi Nomurafe316bf2012-03-02 10:38:33 +01001123 if (bdev->bd_invalidated) {
1124 if (!ret)
1125 rescan_partitions(disk, bdev);
1126 else if (ret == -ENOMEDIUM)
1127 invalidate_partitions(disk, bdev);
1128 }
Tejun Heo1196f8b2011-04-21 20:54:45 +02001129 if (ret)
1130 goto out_clear;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001131 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132 struct block_device *whole;
1133 whole = bdget_disk(disk, 0);
1134 ret = -ENOMEM;
1135 if (!whole)
Tejun Heo0762b8b2008-08-25 19:56:12 +09001136 goto out_clear;
NeilBrown37be4122006-12-08 02:36:16 -08001137 BUG_ON(for_part);
Al Viro572c4892007-10-08 13:24:05 -04001138 ret = __blkdev_get(whole, mode, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139 if (ret)
Tejun Heo0762b8b2008-08-25 19:56:12 +09001140 goto out_clear;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141 bdev->bd_contains = whole;
Dave Chinnera5491e02010-10-21 11:49:26 +11001142 bdev_inode_switch_bdi(bdev->bd_inode,
1143 whole->bd_inode->i_data.backing_dev_info);
Tejun Heo89f97492008-11-05 10:21:06 +01001144 bdev->bd_part = disk_get_part(disk, partno);
Tejun Heoe71bf0d2008-09-03 09:03:02 +02001145 if (!(disk->flags & GENHD_FL_UP) ||
Tejun Heo89f97492008-11-05 10:21:06 +01001146 !bdev->bd_part || !bdev->bd_part->nr_sects) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147 ret = -ENXIO;
Tejun Heo0762b8b2008-08-25 19:56:12 +09001148 goto out_clear;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 }
Tejun Heo89f97492008-11-05 10:21:06 +01001150 bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151 }
1152 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153 if (bdev->bd_contains == bdev) {
Tejun Heo1196f8b2011-04-21 20:54:45 +02001154 ret = 0;
1155 if (bdev->bd_disk->fops->open)
Al Viro572c4892007-10-08 13:24:05 -04001156 ret = bdev->bd_disk->fops->open(bdev, mode);
Tejun Heo1196f8b2011-04-21 20:54:45 +02001157 /* the same as first opener case, read comment there */
Jun'ichi Nomurafe316bf2012-03-02 10:38:33 +01001158 if (bdev->bd_invalidated) {
1159 if (!ret)
1160 rescan_partitions(bdev->bd_disk, bdev);
1161 else if (ret == -ENOMEDIUM)
1162 invalidate_partitions(bdev->bd_disk, bdev);
1163 }
Tejun Heo1196f8b2011-04-21 20:54:45 +02001164 if (ret)
1165 goto out_unlock_bdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166 }
Tejun Heo69e02c52011-03-09 19:54:27 +01001167 /* only one opener holds refs to the module and disk */
Tejun Heo69e02c52011-03-09 19:54:27 +01001168 put_disk(disk);
Tejun Heo523e1d32011-10-19 14:31:07 +02001169 module_put(owner);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170 }
1171 bdev->bd_openers++;
NeilBrown37be4122006-12-08 02:36:16 -08001172 if (for_part)
1173 bdev->bd_part_count++;
Arjan van de Venc039e312006-03-23 03:00:28 -08001174 mutex_unlock(&bdev->bd_mutex);
Tejun Heo69e02c52011-03-09 19:54:27 +01001175 disk_unblock_events(disk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176 return 0;
1177
Tejun Heo0762b8b2008-08-25 19:56:12 +09001178 out_clear:
Tejun Heo89f97492008-11-05 10:21:06 +01001179 disk_put_part(bdev->bd_part);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180 bdev->bd_disk = NULL;
Tejun Heo0762b8b2008-08-25 19:56:12 +09001181 bdev->bd_part = NULL;
Andi Kleen87192a22012-01-12 17:20:34 -08001182 bdev->bd_queue = NULL;
Dave Chinnera5491e02010-10-21 11:49:26 +11001183 bdev_inode_switch_bdi(bdev->bd_inode, &default_backing_dev_info);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001184 if (bdev != bdev->bd_contains)
Al Viro572c4892007-10-08 13:24:05 -04001185 __blkdev_put(bdev->bd_contains, mode, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001186 bdev->bd_contains = NULL;
Tejun Heo0762b8b2008-08-25 19:56:12 +09001187 out_unlock_bdev:
Arjan van de Venc039e312006-03-23 03:00:28 -08001188 mutex_unlock(&bdev->bd_mutex);
Tejun Heo69e02c52011-03-09 19:54:27 +01001189 disk_unblock_events(disk);
Tejun Heo0762b8b2008-08-25 19:56:12 +09001190 put_disk(disk);
Tejun Heo523e1d32011-10-19 14:31:07 +02001191 module_put(owner);
Dan Carpenter4345cab2011-03-19 13:53:31 +01001192 out:
Tejun Heo0762b8b2008-08-25 19:56:12 +09001193 bdput(bdev);
1194
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195 return ret;
1196}
1197
Tejun Heod4d77622010-11-13 11:55:18 +01001198/**
1199 * blkdev_get - open a block device
1200 * @bdev: block_device to open
1201 * @mode: FMODE_* mask
1202 * @holder: exclusive holder identifier
1203 *
1204 * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is
1205 * open with exclusive access. Specifying %FMODE_EXCL with %NULL
1206 * @holder is invalid. Exclusive opens may nest for the same @holder.
1207 *
1208 * On success, the reference count of @bdev is unchanged. On failure,
1209 * @bdev is put.
1210 *
1211 * CONTEXT:
1212 * Might sleep.
1213 *
1214 * RETURNS:
1215 * 0 on success, -errno on failure.
1216 */
Tejun Heoe525fd82010-11-13 11:55:17 +01001217int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218{
Tejun Heoe525fd82010-11-13 11:55:17 +01001219 struct block_device *whole = NULL;
1220 int res;
1221
1222 WARN_ON_ONCE((mode & FMODE_EXCL) && !holder);
1223
1224 if ((mode & FMODE_EXCL) && holder) {
1225 whole = bd_start_claiming(bdev, holder);
1226 if (IS_ERR(whole)) {
1227 bdput(bdev);
1228 return PTR_ERR(whole);
1229 }
1230 }
1231
1232 res = __blkdev_get(bdev, mode, 0);
1233
1234 if (whole) {
Tejun Heod4dc2102011-04-21 20:54:46 +02001235 struct gendisk *disk = whole->bd_disk;
1236
Tejun Heo6a027ef2010-11-13 11:55:17 +01001237 /* finish claiming */
Tejun Heo77ea8872010-12-08 20:57:37 +01001238 mutex_lock(&bdev->bd_mutex);
Tejun Heo6a027ef2010-11-13 11:55:17 +01001239 spin_lock(&bdev_lock);
1240
Tejun Heo77ea8872010-12-08 20:57:37 +01001241 if (!res) {
Tejun Heo6a027ef2010-11-13 11:55:17 +01001242 BUG_ON(!bd_may_claim(bdev, whole, holder));
1243 /*
1244 * Note that for a whole device bd_holders
1245 * will be incremented twice, and bd_holder
1246 * will be set to bd_may_claim before being
1247 * set to holder
1248 */
1249 whole->bd_holders++;
1250 whole->bd_holder = bd_may_claim;
1251 bdev->bd_holders++;
1252 bdev->bd_holder = holder;
1253 }
1254
1255 /* tell others that we're done */
1256 BUG_ON(whole->bd_claiming != holder);
1257 whole->bd_claiming = NULL;
1258 wake_up_bit(&whole->bd_claiming, 0);
1259
1260 spin_unlock(&bdev_lock);
Tejun Heo77ea8872010-12-08 20:57:37 +01001261
1262 /*
Tejun Heod4dc2102011-04-21 20:54:46 +02001263 * Block event polling for write claims if requested. Any
1264 * write holder makes the write_holder state stick until
1265 * all are released. This is good enough and tracking
1266 * individual writeable reference is too fragile given the
1267 * way @mode is used in blkdev_get/put().
Tejun Heo77ea8872010-12-08 20:57:37 +01001268 */
Tejun Heo4c49ff32011-06-01 08:27:41 +02001269 if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder &&
1270 (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
Tejun Heo77ea8872010-12-08 20:57:37 +01001271 bdev->bd_write_holder = true;
Tejun Heod4dc2102011-04-21 20:54:46 +02001272 disk_block_events(disk);
Tejun Heo77ea8872010-12-08 20:57:37 +01001273 }
1274
1275 mutex_unlock(&bdev->bd_mutex);
Tejun Heo6a027ef2010-11-13 11:55:17 +01001276 bdput(whole);
Tejun Heoe525fd82010-11-13 11:55:17 +01001277 }
1278
1279 return res;
NeilBrown37be4122006-12-08 02:36:16 -08001280}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281EXPORT_SYMBOL(blkdev_get);
1282
Tejun Heod4d77622010-11-13 11:55:18 +01001283/**
1284 * blkdev_get_by_path - open a block device by name
1285 * @path: path to the block device to open
1286 * @mode: FMODE_* mask
1287 * @holder: exclusive holder identifier
1288 *
1289 * Open the blockdevice described by the device file at @path. @mode
1290 * and @holder are identical to blkdev_get().
1291 *
1292 * On success, the returned block_device has reference count of one.
1293 *
1294 * CONTEXT:
1295 * Might sleep.
1296 *
1297 * RETURNS:
1298 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1299 */
1300struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
1301 void *holder)
1302{
1303 struct block_device *bdev;
1304 int err;
1305
1306 bdev = lookup_bdev(path);
1307 if (IS_ERR(bdev))
1308 return bdev;
1309
1310 err = blkdev_get(bdev, mode, holder);
1311 if (err)
1312 return ERR_PTR(err);
1313
Chuck Ebberte51900f2011-02-16 18:11:53 -05001314 if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) {
1315 blkdev_put(bdev, mode);
1316 return ERR_PTR(-EACCES);
1317 }
1318
Tejun Heod4d77622010-11-13 11:55:18 +01001319 return bdev;
1320}
1321EXPORT_SYMBOL(blkdev_get_by_path);
1322
1323/**
1324 * blkdev_get_by_dev - open a block device by device number
1325 * @dev: device number of block device to open
1326 * @mode: FMODE_* mask
1327 * @holder: exclusive holder identifier
1328 *
1329 * Open the blockdevice described by device number @dev. @mode and
1330 * @holder are identical to blkdev_get().
1331 *
1332 * Use it ONLY if you really do not have anything better - i.e. when
1333 * you are behind a truly sucky interface and all you are given is a
1334 * device number. _Never_ to be used for internal purposes. If you
1335 * ever need it - reconsider your API.
1336 *
1337 * On success, the returned block_device has reference count of one.
1338 *
1339 * CONTEXT:
1340 * Might sleep.
1341 *
1342 * RETURNS:
1343 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1344 */
1345struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
1346{
1347 struct block_device *bdev;
1348 int err;
1349
1350 bdev = bdget(dev);
1351 if (!bdev)
1352 return ERR_PTR(-ENOMEM);
1353
1354 err = blkdev_get(bdev, mode, holder);
1355 if (err)
1356 return ERR_PTR(err);
1357
1358 return bdev;
1359}
1360EXPORT_SYMBOL(blkdev_get_by_dev);
1361
Linus Torvalds1da177e2005-04-16 15:20:36 -07001362static int blkdev_open(struct inode * inode, struct file * filp)
1363{
1364 struct block_device *bdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001365
1366 /*
1367 * Preserve backwards compatibility and allow large file access
1368 * even if userspace doesn't ask for it explicitly. Some mkfs
1369 * binary needs it. We might want to drop this workaround
1370 * during an unstable branch.
1371 */
1372 filp->f_flags |= O_LARGEFILE;
1373
Al Viro572c4892007-10-08 13:24:05 -04001374 if (filp->f_flags & O_NDELAY)
1375 filp->f_mode |= FMODE_NDELAY;
1376 if (filp->f_flags & O_EXCL)
1377 filp->f_mode |= FMODE_EXCL;
1378 if ((filp->f_flags & O_ACCMODE) == 3)
1379 filp->f_mode |= FMODE_WRITE_IOCTL;
1380
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381 bdev = bd_acquire(inode);
Pavel Emelianov6a2aae02006-10-28 10:38:33 -07001382 if (bdev == NULL)
1383 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001384
Al Viro572c4892007-10-08 13:24:05 -04001385 filp->f_mapping = bdev->bd_inode->i_mapping;
1386
Tejun Heoe525fd82010-11-13 11:55:17 +01001387 return blkdev_get(bdev, filp->f_mode, filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388}
1389
Al Viro4385bab2013-05-05 22:11:03 -04001390static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001391{
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001392 struct gendisk *disk = bdev->bd_disk;
NeilBrown37be4122006-12-08 02:36:16 -08001393 struct block_device *victim = NULL;
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001394
NeilBrown6796bf52006-12-08 02:36:16 -08001395 mutex_lock_nested(&bdev->bd_mutex, for_part);
NeilBrown37be4122006-12-08 02:36:16 -08001396 if (for_part)
1397 bdev->bd_part_count--;
1398
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001399 if (!--bdev->bd_openers) {
Tejun Heo6a027ef2010-11-13 11:55:17 +01001400 WARN_ON_ONCE(bdev->bd_holders);
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001401 sync_blockdev(bdev);
1402 kill_bdev(bdev);
NeilBrown94007752011-09-10 17:20:21 +10001403 /* ->release can cause the old bdi to disappear,
1404 * so must switch it out first
1405 */
1406 bdev_inode_switch_bdi(bdev->bd_inode,
1407 &default_backing_dev_info);
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001408 }
1409 if (bdev->bd_contains == bdev) {
1410 if (disk->fops->release)
Al Virodb2a1442013-05-05 21:52:57 -04001411 disk->fops->release(disk, mode);
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001412 }
1413 if (!bdev->bd_openers) {
1414 struct module *owner = disk->fops->owner;
1415
Tejun Heo0762b8b2008-08-25 19:56:12 +09001416 disk_put_part(bdev->bd_part);
1417 bdev->bd_part = NULL;
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001418 bdev->bd_disk = NULL;
NeilBrown37be4122006-12-08 02:36:16 -08001419 if (bdev != bdev->bd_contains)
1420 victim = bdev->bd_contains;
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001421 bdev->bd_contains = NULL;
Tejun Heo523e1d32011-10-19 14:31:07 +02001422
1423 put_disk(disk);
1424 module_put(owner);
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001425 }
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001426 mutex_unlock(&bdev->bd_mutex);
1427 bdput(bdev);
NeilBrown37be4122006-12-08 02:36:16 -08001428 if (victim)
Al Viro9a1c3542008-02-22 20:40:24 -05001429 __blkdev_put(victim, mode, 1);
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001430}
1431
Al Viro4385bab2013-05-05 22:11:03 -04001432void blkdev_put(struct block_device *bdev, fmode_t mode)
NeilBrown37be4122006-12-08 02:36:16 -08001433{
Tejun Heo85ef06d2011-07-01 16:17:47 +02001434 mutex_lock(&bdev->bd_mutex);
1435
Tejun Heoe525fd82010-11-13 11:55:17 +01001436 if (mode & FMODE_EXCL) {
Tejun Heo6a027ef2010-11-13 11:55:17 +01001437 bool bdev_free;
1438
1439 /*
1440 * Release a claim on the device. The holder fields
1441 * are protected with bdev_lock. bd_mutex is to
1442 * synchronize disk_holder unlinking.
1443 */
Tejun Heo6a027ef2010-11-13 11:55:17 +01001444 spin_lock(&bdev_lock);
1445
1446 WARN_ON_ONCE(--bdev->bd_holders < 0);
1447 WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0);
1448
1449 /* bd_contains might point to self, check in a separate step */
1450 if ((bdev_free = !bdev->bd_holders))
1451 bdev->bd_holder = NULL;
1452 if (!bdev->bd_contains->bd_holders)
1453 bdev->bd_contains->bd_holder = NULL;
1454
1455 spin_unlock(&bdev_lock);
1456
Tejun Heo77ea8872010-12-08 20:57:37 +01001457 /*
1458 * If this was the last claim, remove holder link and
1459 * unblock evpoll if it was a write holder.
1460 */
Tejun Heo85ef06d2011-07-01 16:17:47 +02001461 if (bdev_free && bdev->bd_write_holder) {
1462 disk_unblock_events(bdev->bd_disk);
1463 bdev->bd_write_holder = false;
Tejun Heo77ea8872010-12-08 20:57:37 +01001464 }
Tejun Heo69362172011-03-09 19:54:27 +01001465 }
Tejun Heo77ea8872010-12-08 20:57:37 +01001466
Tejun Heo85ef06d2011-07-01 16:17:47 +02001467 /*
1468 * Trigger event checking and tell drivers to flush MEDIA_CHANGE
1469 * event. This is to ensure detection of media removal commanded
1470 * from userland - e.g. eject(1).
1471 */
1472 disk_flush_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE);
1473
1474 mutex_unlock(&bdev->bd_mutex);
1475
Al Viro4385bab2013-05-05 22:11:03 -04001476 __blkdev_put(bdev, mode, 0);
NeilBrown37be4122006-12-08 02:36:16 -08001477}
Peter Zijlstra2e7b6512006-12-08 02:36:13 -08001478EXPORT_SYMBOL(blkdev_put);
1479
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480static int blkdev_close(struct inode * inode, struct file * filp)
1481{
1482 struct block_device *bdev = I_BDEV(filp->f_mapping->host);
Al Viro4385bab2013-05-05 22:11:03 -04001483 blkdev_put(bdev, filp->f_mode);
1484 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001485}
1486
Arnd Bergmannbb93e3a2005-06-23 00:10:15 -07001487static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488{
Al Viro56b26ad2008-09-19 03:17:36 -04001489 struct block_device *bdev = I_BDEV(file->f_mapping->host);
1490 fmode_t mode = file->f_mode;
Christoph Hellwigfd4ce1a2008-11-05 14:58:42 +01001491
1492 /*
1493 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
1494 * to updated it before every ioctl.
1495 */
Al Viro56b26ad2008-09-19 03:17:36 -04001496 if (file->f_flags & O_NDELAY)
Christoph Hellwigfd4ce1a2008-11-05 14:58:42 +01001497 mode |= FMODE_NDELAY;
1498 else
1499 mode &= ~FMODE_NDELAY;
1500
Al Viro56b26ad2008-09-19 03:17:36 -04001501 return blkdev_ioctl(bdev, mode, cmd, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001502}
1503
Theodore Ts'o87d8fe12009-01-03 09:47:09 -05001504/*
Christoph Hellwigeef99382009-08-20 17:43:41 +02001505 * Write data to the block device. Only intended for the block device itself
1506 * and the raw driver which basically is a fake block device.
1507 *
1508 * Does not take i_mutex for the write and thus is not for general purpose
1509 * use.
1510 */
1511ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
1512 unsigned long nr_segs, loff_t pos)
1513{
1514 struct file *file = iocb->ki_filp;
Jianpeng Ma53362a02012-08-02 09:50:39 +02001515 struct blk_plug plug;
Christoph Hellwigeef99382009-08-20 17:43:41 +02001516 ssize_t ret;
1517
1518 BUG_ON(iocb->ki_pos != pos);
1519
Jianpeng Ma53362a02012-08-02 09:50:39 +02001520 blk_start_plug(&plug);
Al Viro41fc56d2014-02-09 12:58:52 -05001521 ret = __generic_file_aio_write(iocb, iov, nr_segs);
Christoph Hellwig02afc272013-09-04 15:04:40 +02001522 if (ret > 0) {
Christoph Hellwigeef99382009-08-20 17:43:41 +02001523 ssize_t err;
1524
1525 err = generic_write_sync(file, pos, ret);
Dan Carpenter45d4f852014-04-03 14:47:17 -07001526 if (err < 0)
Christoph Hellwigeef99382009-08-20 17:43:41 +02001527 ret = err;
1528 }
Jianpeng Ma53362a02012-08-02 09:50:39 +02001529 blk_finish_plug(&plug);
Christoph Hellwigeef99382009-08-20 17:43:41 +02001530 return ret;
1531}
1532EXPORT_SYMBOL_GPL(blkdev_aio_write);
1533
Linus Torvalds684c9aa2012-12-07 16:48:39 -08001534static ssize_t blkdev_aio_read(struct kiocb *iocb, const struct iovec *iov,
1535 unsigned long nr_segs, loff_t pos)
1536{
1537 struct file *file = iocb->ki_filp;
1538 struct inode *bd_inode = file->f_mapping->host;
1539 loff_t size = i_size_read(bd_inode);
1540
1541 if (pos >= size)
1542 return 0;
1543
1544 size -= pos;
Kent Overstreet73a70752013-05-09 15:03:42 -07001545 if (size < iocb->ki_nbytes)
Linus Torvalds684c9aa2012-12-07 16:48:39 -08001546 nr_segs = iov_shorten((struct iovec *)iov, nr_segs, size);
1547 return generic_file_aio_read(iocb, iov, nr_segs, pos);
1548}
1549
Christoph Hellwigeef99382009-08-20 17:43:41 +02001550/*
Theodore Ts'o87d8fe12009-01-03 09:47:09 -05001551 * Try to release a page associated with block device when the system
1552 * is under memory pressure.
1553 */
1554static int blkdev_releasepage(struct page *page, gfp_t wait)
1555{
1556 struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super;
1557
1558 if (super && super->s_op->bdev_try_to_free_page)
1559 return super->s_op->bdev_try_to_free_page(super, page, wait);
1560
1561 return try_to_free_buffers(page);
1562}
1563
Adrian Bunk4c54ac62008-02-18 13:48:31 +01001564static const struct address_space_operations def_blk_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001565 .readpage = blkdev_readpage,
1566 .writepage = blkdev_writepage,
Nick Piggin6272b5a2007-10-16 01:25:04 -07001567 .write_begin = blkdev_write_begin,
1568 .write_end = blkdev_write_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001569 .writepages = generic_writepages,
Theodore Ts'o87d8fe12009-01-03 09:47:09 -05001570 .releasepage = blkdev_releasepage,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001571 .direct_IO = blkdev_direct_IO,
Mel Gormanb4597222013-07-03 15:02:05 -07001572 .is_dirty_writeback = buffer_check_dirty_writeback,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001573};
1574
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -08001575const struct file_operations def_blk_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001576 .open = blkdev_open,
1577 .release = blkdev_close,
1578 .llseek = block_llseek,
Badari Pulavarty543ade12006-09-30 23:28:48 -07001579 .read = do_sync_read,
1580 .write = do_sync_write,
Linus Torvalds684c9aa2012-12-07 16:48:39 -08001581 .aio_read = blkdev_aio_read,
Christoph Hellwigeef99382009-08-20 17:43:41 +02001582 .aio_write = blkdev_aio_write,
Linus Torvalds1e8b3332012-11-29 10:49:50 -08001583 .mmap = generic_file_mmap,
Andrew Mortonb1dd3b22010-04-06 14:35:00 -07001584 .fsync = blkdev_fsync,
Arnd Bergmannbb93e3a2005-06-23 00:10:15 -07001585 .unlocked_ioctl = block_ioctl,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001586#ifdef CONFIG_COMPAT
1587 .compat_ioctl = compat_blkdev_ioctl,
1588#endif
Linus Torvalds1e8b3332012-11-29 10:49:50 -08001589 .splice_read = generic_file_splice_read,
1590 .splice_write = generic_file_splice_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001591};
1592
1593int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg)
1594{
1595 int res;
1596 mm_segment_t old_fs = get_fs();
1597 set_fs(KERNEL_DS);
Al Viro56b26ad2008-09-19 03:17:36 -04001598 res = blkdev_ioctl(bdev, 0, cmd, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001599 set_fs(old_fs);
1600 return res;
1601}
1602
1603EXPORT_SYMBOL(ioctl_by_bdev);
1604
1605/**
1606 * lookup_bdev - lookup a struct block_device by name
Randy Dunlap94e29592009-01-06 14:41:15 -08001607 * @pathname: special file representing the block device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001608 *
Randy Dunlap57d1b532008-10-09 10:42:38 +02001609 * Get a reference to the blockdevice at @pathname in the current
Linus Torvalds1da177e2005-04-16 15:20:36 -07001610 * namespace if possible and return it. Return ERR_PTR(error)
1611 * otherwise.
1612 */
Al Viro421748e2008-08-02 01:04:36 -04001613struct block_device *lookup_bdev(const char *pathname)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001614{
1615 struct block_device *bdev;
1616 struct inode *inode;
Al Viro421748e2008-08-02 01:04:36 -04001617 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001618 int error;
1619
Al Viro421748e2008-08-02 01:04:36 -04001620 if (!pathname || !*pathname)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001621 return ERR_PTR(-EINVAL);
1622
Al Viro421748e2008-08-02 01:04:36 -04001623 error = kern_path(pathname, LOOKUP_FOLLOW, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001624 if (error)
1625 return ERR_PTR(error);
1626
Al Viro421748e2008-08-02 01:04:36 -04001627 inode = path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001628 error = -ENOTBLK;
1629 if (!S_ISBLK(inode->i_mode))
1630 goto fail;
1631 error = -EACCES;
Al Viro421748e2008-08-02 01:04:36 -04001632 if (path.mnt->mnt_flags & MNT_NODEV)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001633 goto fail;
1634 error = -ENOMEM;
1635 bdev = bd_acquire(inode);
1636 if (!bdev)
1637 goto fail;
1638out:
Al Viro421748e2008-08-02 01:04:36 -04001639 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001640 return bdev;
1641fail:
1642 bdev = ERR_PTR(error);
1643 goto out;
1644}
Al Virod5686b42008-08-01 05:00:11 -04001645EXPORT_SYMBOL(lookup_bdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001646
NeilBrown93b270f2011-02-24 17:25:47 +11001647int __invalidate_device(struct block_device *bdev, bool kill_dirty)
David Howellsb71e8a42006-08-29 19:06:11 +01001648{
1649 struct super_block *sb = get_super(bdev);
1650 int res = 0;
1651
1652 if (sb) {
1653 /*
1654 * no need to lock the super, get_super holds the
1655 * read mutex so the filesystem cannot go away
1656 * under us (->put_super runs with the write lock
1657 * hold).
1658 */
1659 shrink_dcache_sb(sb);
NeilBrown93b270f2011-02-24 17:25:47 +11001660 res = invalidate_inodes(sb, kill_dirty);
David Howellsb71e8a42006-08-29 19:06:11 +01001661 drop_super(sb);
1662 }
Peter Zijlstraf98393a2007-05-06 14:49:54 -07001663 invalidate_bdev(bdev);
David Howellsb71e8a42006-08-29 19:06:11 +01001664 return res;
1665}
1666EXPORT_SYMBOL(__invalidate_device);
Jan Kara5c0d6b62012-07-03 16:45:31 +02001667
1668void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg)
1669{
1670 struct inode *inode, *old_inode = NULL;
1671
1672 spin_lock(&inode_sb_list_lock);
1673 list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) {
1674 struct address_space *mapping = inode->i_mapping;
1675
1676 spin_lock(&inode->i_lock);
1677 if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) ||
1678 mapping->nrpages == 0) {
1679 spin_unlock(&inode->i_lock);
1680 continue;
1681 }
1682 __iget(inode);
1683 spin_unlock(&inode->i_lock);
1684 spin_unlock(&inode_sb_list_lock);
1685 /*
1686 * We hold a reference to 'inode' so it couldn't have been
1687 * removed from s_inodes list while we dropped the
1688 * inode_sb_list_lock. We cannot iput the inode now as we can
1689 * be holding the last reference and we cannot iput it under
1690 * inode_sb_list_lock. So we keep the reference and iput it
1691 * later.
1692 */
1693 iput(old_inode);
1694 old_inode = inode;
1695
1696 func(I_BDEV(inode), arg);
1697
1698 spin_lock(&inode_sb_list_lock);
1699 }
1700 spin_unlock(&inode_sb_list_lock);
1701 iput(old_inode);
1702}