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block: move fs/block_dev.c to block/bdev.c

Move it together with the rest of the block layer.

Christoph Hellwig committed 5 years ago

Commit 0dca4461 parent cd82cca7 files · +8 −9Browse files

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1+// SPDX-License-Identifier: GPL-2.0-only
2+/*
3+ * Copyright (C) 1991, 1992 Linus Torvalds
4+ * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
5+ * Copyright (C) 2016 - 2020 Christoph Hellwig
6+ */
7+
8+#include <linux/init.h>
9+#include <linux/mm.h>
10+#include <linux/slab.h>
11+#include <linux/kmod.h>
12+#include <linux/major.h>
13+#include <linux/device_cgroup.h>
14+#include <linux/blkdev.h>
15+#include <linux/backing-dev.h>
16+#include <linux/module.h>
17+#include <linux/blkpg.h>
18+#include <linux/magic.h>
19+#include <linux/buffer_head.h>
20+#include <linux/swap.h>
21+#include <linux/writeback.h>
22+#include <linux/mount.h>
23+#include <linux/pseudo_fs.h>
24+#include <linux/uio.h>
25+#include <linux/namei.h>
26+#include <linux/cleancache.h>
27+#include <linux/part_stat.h>
28+#include <linux/uaccess.h>
29+#include "../fs/internal.h"
30+#include "blk.h"
31+
32+struct bdev_inode {
33+ struct block_device bdev;
34+ struct inode vfs_inode;
35+};
36+
37+static inline struct bdev_inode *BDEV_I(struct inode *inode)
38+{
39+ return container_of(inode, struct bdev_inode, vfs_inode);
40+}
41+
42+struct block_device *I_BDEV(struct inode *inode)
43+{
44+ return &BDEV_I(inode)->bdev;
45+}
46+EXPORT_SYMBOL(I_BDEV);
47+
48+static void bdev_write_inode(struct block_device *bdev)
49+{
50+ struct inode *inode = bdev->bd_inode;
51+ int ret;
52+
53+ spin_lock(&inode->i_lock);
54+ while (inode->i_state & I_DIRTY) {
55+ spin_unlock(&inode->i_lock);
56+ ret = write_inode_now(inode, true);
57+ if (ret) {
58+ char name[BDEVNAME_SIZE];
59+ pr_warn_ratelimited("VFS: Dirty inode writeback failed "
60+ "for block device %s (err=%d).\n",
61+ bdevname(bdev, name), ret);
62+ }
63+ spin_lock(&inode->i_lock);
64+ }
65+ spin_unlock(&inode->i_lock);
66+}
67+
68+/* Kill _all_ buffers and pagecache , dirty or not.. */
69+static void kill_bdev(struct block_device *bdev)
70+{
71+ struct address_space *mapping = bdev->bd_inode->i_mapping;
72+
73+ if (mapping_empty(mapping))
74+ return;
75+
76+ invalidate_bh_lrus();
77+ truncate_inode_pages(mapping, 0);
78+}
79+
80+/* Invalidate clean unused buffers and pagecache. */
81+void invalidate_bdev(struct block_device *bdev)
82+{
83+ struct address_space *mapping = bdev->bd_inode->i_mapping;
84+
85+ if (mapping->nrpages) {
86+ invalidate_bh_lrus();
87+ lru_add_drain_all(); /* make sure all lru add caches are flushed */
88+ invalidate_mapping_pages(mapping, 0, -1);
89+ }
90+ /* 99% of the time, we don't need to flush the cleancache on the bdev.
91+ * But, for the strange corners, lets be cautious
92+ */
93+ cleancache_invalidate_inode(mapping);
94+}
95+EXPORT_SYMBOL(invalidate_bdev);
96+
97+/*
98+ * Drop all buffers & page cache for given bdev range. This function bails
99+ * with error if bdev has other exclusive owner (such as filesystem).
100+ */
101+int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
102+ loff_t lstart, loff_t lend)
103+{
104+ /*
105+ * If we don't hold exclusive handle for the device, upgrade to it
106+ * while we discard the buffer cache to avoid discarding buffers
107+ * under live filesystem.
108+ */
109+ if (!(mode & FMODE_EXCL)) {
110+ int err = bd_prepare_to_claim(bdev, truncate_bdev_range);
111+ if (err)
112+ goto invalidate;
113+ }
114+
115+ truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
116+ if (!(mode & FMODE_EXCL))
117+ bd_abort_claiming(bdev, truncate_bdev_range);
118+ return 0;
119+
120+invalidate:
121+ /*
122+ * Someone else has handle exclusively open. Try invalidating instead.
123+ * The 'end' argument is inclusive so the rounding is safe.
124+ */
125+ return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping,
126+ lstart >> PAGE_SHIFT,
127+ lend >> PAGE_SHIFT);
128+}
129+
130+static void set_init_blocksize(struct block_device *bdev)
131+{
132+ unsigned int bsize = bdev_logical_block_size(bdev);
133+ loff_t size = i_size_read(bdev->bd_inode);
134+
135+ while (bsize < PAGE_SIZE) {
136+ if (size & bsize)
137+ break;
138+ bsize <<= 1;
139+ }
140+ bdev->bd_inode->i_blkbits = blksize_bits(bsize);
141+}
142+
143+int set_blocksize(struct block_device *bdev, int size)
144+{
145+ /* Size must be a power of two, and between 512 and PAGE_SIZE */
146+ if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
147+ return -EINVAL;
148+
149+ /* Size cannot be smaller than the size supported by the device */
150+ if (size < bdev_logical_block_size(bdev))
151+ return -EINVAL;
152+
153+ /* Don't change the size if it is same as current */
154+ if (bdev->bd_inode->i_blkbits != blksize_bits(size)) {
155+ sync_blockdev(bdev);
156+ bdev->bd_inode->i_blkbits = blksize_bits(size);
157+ kill_bdev(bdev);
158+ }
159+ return 0;
160+}
161+
162+EXPORT_SYMBOL(set_blocksize);
163+
164+int sb_set_blocksize(struct super_block *sb, int size)
165+{
166+ if (set_blocksize(sb->s_bdev, size))
167+ return 0;
168+ /* If we get here, we know size is power of two
169+ * and it's value is between 512 and PAGE_SIZE */
170+ sb->s_blocksize = size;
171+ sb->s_blocksize_bits = blksize_bits(size);
172+ return sb->s_blocksize;
173+}
174+
175+EXPORT_SYMBOL(sb_set_blocksize);
176+
177+int sb_min_blocksize(struct super_block *sb, int size)
178+{
179+ int minsize = bdev_logical_block_size(sb->s_bdev);
180+ if (size < minsize)
181+ size = minsize;
182+ return sb_set_blocksize(sb, size);
183+}
184+
185+EXPORT_SYMBOL(sb_min_blocksize);
186+
187+int __sync_blockdev(struct block_device *bdev, int wait)
188+{
189+ if (!bdev)
190+ return 0;
191+ if (!wait)
192+ return filemap_flush(bdev->bd_inode->i_mapping);
193+ return filemap_write_and_wait(bdev->bd_inode->i_mapping);
194+}
195+
196+/*
197+ * Write out and wait upon all the dirty data associated with a block
198+ * device via its mapping. Does not take the superblock lock.
199+ */
200+int sync_blockdev(struct block_device *bdev)
201+{
202+ return __sync_blockdev(bdev, 1);
203+}
204+EXPORT_SYMBOL(sync_blockdev);
205+
206+/*
207+ * Write out and wait upon all dirty data associated with this
208+ * device. Filesystem data as well as the underlying block
209+ * device. Takes the superblock lock.
210+ */
211+int fsync_bdev(struct block_device *bdev)
212+{
213+ struct super_block *sb = get_super(bdev);
214+ if (sb) {
215+ int res = sync_filesystem(sb);
216+ drop_super(sb);
217+ return res;
218+ }
219+ return sync_blockdev(bdev);
220+}
221+EXPORT_SYMBOL(fsync_bdev);
222+
223+/**
224+ * freeze_bdev -- lock a filesystem and force it into a consistent state
225+ * @bdev: blockdevice to lock
226+ *
227+ * If a superblock is found on this device, we take the s_umount semaphore
228+ * on it to make sure nobody unmounts until the snapshot creation is done.
229+ * The reference counter (bd_fsfreeze_count) guarantees that only the last
230+ * unfreeze process can unfreeze the frozen filesystem actually when multiple
231+ * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
232+ * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
233+ * actually.
234+ */
235+int freeze_bdev(struct block_device *bdev)
236+{
237+ struct super_block *sb;
238+ int error = 0;
239+
240+ mutex_lock(&bdev->bd_fsfreeze_mutex);
241+ if (++bdev->bd_fsfreeze_count > 1)
242+ goto done;
243+
244+ sb = get_active_super(bdev);
245+ if (!sb)
246+ goto sync;
247+ if (sb->s_op->freeze_super)
248+ error = sb->s_op->freeze_super(sb);
249+ else
250+ error = freeze_super(sb);
251+ deactivate_super(sb);
252+
253+ if (error) {
254+ bdev->bd_fsfreeze_count--;
255+ goto done;
256+ }
257+ bdev->bd_fsfreeze_sb = sb;
258+
259+sync:
260+ sync_blockdev(bdev);
261+done:
262+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
263+ return error;
264+}
265+EXPORT_SYMBOL(freeze_bdev);
266+
267+/**
268+ * thaw_bdev -- unlock filesystem
269+ * @bdev: blockdevice to unlock
270+ *
271+ * Unlocks the filesystem and marks it writeable again after freeze_bdev().
272+ */
273+int thaw_bdev(struct block_device *bdev)
274+{
275+ struct super_block *sb;
276+ int error = -EINVAL;
277+
278+ mutex_lock(&bdev->bd_fsfreeze_mutex);
279+ if (!bdev->bd_fsfreeze_count)
280+ goto out;
281+
282+ error = 0;
283+ if (--bdev->bd_fsfreeze_count > 0)
284+ goto out;
285+
286+ sb = bdev->bd_fsfreeze_sb;
287+ if (!sb)
288+ goto out;
289+
290+ if (sb->s_op->thaw_super)
291+ error = sb->s_op->thaw_super(sb);
292+ else
293+ error = thaw_super(sb);
294+ if (error)
295+ bdev->bd_fsfreeze_count++;
296+ else
297+ bdev->bd_fsfreeze_sb = NULL;
298+out:
299+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
300+ return error;
301+}
302+EXPORT_SYMBOL(thaw_bdev);
303+
304+/**
305+ * bdev_read_page() - Start reading a page from a block device
306+ * @bdev: The device to read the page from
307+ * @sector: The offset on the device to read the page to (need not be aligned)
308+ * @page: The page to read
309+ *
310+ * On entry, the page should be locked. It will be unlocked when the page
311+ * has been read. If the block driver implements rw_page synchronously,
312+ * that will be true on exit from this function, but it need not be.
313+ *
314+ * Errors returned by this function are usually "soft", eg out of memory, or
315+ * queue full; callers should try a different route to read this page rather
316+ * than propagate an error back up the stack.
317+ *
318+ * Return: negative errno if an error occurs, 0 if submission was successful.
319+ */
320+int bdev_read_page(struct block_device *bdev, sector_t sector,
321+ struct page *page)
322+{
323+ const struct block_device_operations *ops = bdev->bd_disk->fops;
324+ int result = -EOPNOTSUPP;
325+
326+ if (!ops->rw_page || bdev_get_integrity(bdev))
327+ return result;
328+
329+ result = blk_queue_enter(bdev->bd_disk->queue, 0);
330+ if (result)
331+ return result;
332+ result = ops->rw_page(bdev, sector + get_start_sect(bdev), page,
333+ REQ_OP_READ);
334+ blk_queue_exit(bdev->bd_disk->queue);
335+ return result;
336+}
337+
338+/**
339+ * bdev_write_page() - Start writing a page to a block device
340+ * @bdev: The device to write the page to
341+ * @sector: The offset on the device to write the page to (need not be aligned)
342+ * @page: The page to write
343+ * @wbc: The writeback_control for the write
344+ *
345+ * On entry, the page should be locked and not currently under writeback.
346+ * On exit, if the write started successfully, the page will be unlocked and
347+ * under writeback. If the write failed already (eg the driver failed to
348+ * queue the page to the device), the page will still be locked. If the
349+ * caller is a ->writepage implementation, it will need to unlock the page.
350+ *
351+ * Errors returned by this function are usually "soft", eg out of memory, or
352+ * queue full; callers should try a different route to write this page rather
353+ * than propagate an error back up the stack.
354+ *
355+ * Return: negative errno if an error occurs, 0 if submission was successful.
356+ */
357+int bdev_write_page(struct block_device *bdev, sector_t sector,
358+ struct page *page, struct writeback_control *wbc)
359+{
360+ int result;
361+ const struct block_device_operations *ops = bdev->bd_disk->fops;
362+
363+ if (!ops->rw_page || bdev_get_integrity(bdev))
364+ return -EOPNOTSUPP;
365+ result = blk_queue_enter(bdev->bd_disk->queue, 0);
366+ if (result)
367+ return result;
368+
369+ set_page_writeback(page);
370+ result = ops->rw_page(bdev, sector + get_start_sect(bdev), page,
371+ REQ_OP_WRITE);
372+ if (result) {
373+ end_page_writeback(page);
374+ } else {
375+ clean_page_buffers(page);
376+ unlock_page(page);
377+ }
378+ blk_queue_exit(bdev->bd_disk->queue);
379+ return result;
380+}
381+
382+/*
383+ * pseudo-fs
384+ */
385+
386+static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
387+static struct kmem_cache * bdev_cachep __read_mostly;
388+
389+static struct inode *bdev_alloc_inode(struct super_block *sb)
390+{
391+ struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL);
392+
393+ if (!ei)
394+ return NULL;
395+ memset(&ei->bdev, 0, sizeof(ei->bdev));
396+ return &ei->vfs_inode;
397+}
398+
399+static void bdev_free_inode(struct inode *inode)
400+{
401+ struct block_device *bdev = I_BDEV(inode);
402+
403+ free_percpu(bdev->bd_stats);
404+ kfree(bdev->bd_meta_info);
405+
406+ if (!bdev_is_partition(bdev)) {
407+ if (bdev->bd_disk && bdev->bd_disk->bdi)
408+ bdi_put(bdev->bd_disk->bdi);
409+ kfree(bdev->bd_disk);
410+ }
411+
412+ if (MAJOR(bdev->bd_dev) == BLOCK_EXT_MAJOR)
413+ blk_free_ext_minor(MINOR(bdev->bd_dev));
414+
415+ kmem_cache_free(bdev_cachep, BDEV_I(inode));
416+}
417+
418+static void init_once(void *data)
419+{
420+ struct bdev_inode *ei = data;
421+
422+ inode_init_once(&ei->vfs_inode);
423+}
424+
425+static void bdev_evict_inode(struct inode *inode)
426+{
427+ truncate_inode_pages_final(&inode->i_data);
428+ invalidate_inode_buffers(inode); /* is it needed here? */
429+ clear_inode(inode);
430+}
431+
432+static const struct super_operations bdev_sops = {
433+ .statfs = simple_statfs,
434+ .alloc_inode = bdev_alloc_inode,
435+ .free_inode = bdev_free_inode,
436+ .drop_inode = generic_delete_inode,
437+ .evict_inode = bdev_evict_inode,
438+};
439+
440+static int bd_init_fs_context(struct fs_context *fc)
441+{
442+ struct pseudo_fs_context *ctx = init_pseudo(fc, BDEVFS_MAGIC);
443+ if (!ctx)
444+ return -ENOMEM;
445+ fc->s_iflags |= SB_I_CGROUPWB;
446+ ctx->ops = &bdev_sops;
447+ return 0;
448+}
449+
450+static struct file_system_type bd_type = {
451+ .name = "bdev",
452+ .init_fs_context = bd_init_fs_context,
453+ .kill_sb = kill_anon_super,
454+};
455+
456+struct super_block *blockdev_superblock __read_mostly;
457+EXPORT_SYMBOL_GPL(blockdev_superblock);
458+
459+void __init bdev_cache_init(void)
460+{
461+ int err;
462+ static struct vfsmount *bd_mnt;
463+
464+ bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
465+ 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
466+ SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC),
467+ init_once);
468+ err = register_filesystem(&bd_type);
469+ if (err)
470+ panic("Cannot register bdev pseudo-fs");
471+ bd_mnt = kern_mount(&bd_type);
472+ if (IS_ERR(bd_mnt))
473+ panic("Cannot create bdev pseudo-fs");
474+ blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
475+}
476+
477+struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
478+{
479+ struct block_device *bdev;
480+ struct inode *inode;
481+
482+ inode = new_inode(blockdev_superblock);
483+ if (!inode)
484+ return NULL;
485+ inode->i_mode = S_IFBLK;
486+ inode->i_rdev = 0;
487+ inode->i_data.a_ops = &def_blk_aops;
488+ mapping_set_gfp_mask(&inode->i_data, GFP_USER);
489+
490+ bdev = I_BDEV(inode);
491+ mutex_init(&bdev->bd_fsfreeze_mutex);
492+ spin_lock_init(&bdev->bd_size_lock);
493+ bdev->bd_disk = disk;
494+ bdev->bd_partno = partno;
495+ bdev->bd_inode = inode;
496+ bdev->bd_stats = alloc_percpu(struct disk_stats);
497+ if (!bdev->bd_stats) {
498+ iput(inode);
499+ return NULL;
500+ }
501+ return bdev;
502+}
503+
504+void bdev_add(struct block_device *bdev, dev_t dev)
505+{
506+ bdev->bd_dev = dev;
507+ bdev->bd_inode->i_rdev = dev;
508+ bdev->bd_inode->i_ino = dev;
509+ insert_inode_hash(bdev->bd_inode);
510+}
511+
512+long nr_blockdev_pages(void)
513+{
514+ struct inode *inode;
515+ long ret = 0;
516+
517+ spin_lock(&blockdev_superblock->s_inode_list_lock);
518+ list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list)
519+ ret += inode->i_mapping->nrpages;
520+ spin_unlock(&blockdev_superblock->s_inode_list_lock);
521+
522+ return ret;
523+}
524+
525+/**
526+ * bd_may_claim - test whether a block device can be claimed
527+ * @bdev: block device of interest
528+ * @whole: whole block device containing @bdev, may equal @bdev
529+ * @holder: holder trying to claim @bdev
530+ *
531+ * Test whether @bdev can be claimed by @holder.
532+ *
533+ * CONTEXT:
534+ * spin_lock(&bdev_lock).
535+ *
536+ * RETURNS:
537+ * %true if @bdev can be claimed, %false otherwise.
538+ */
539+static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
540+ void *holder)
541+{
542+ if (bdev->bd_holder == holder)
543+ return true; /* already a holder */
544+ else if (bdev->bd_holder != NULL)
545+ return false; /* held by someone else */
546+ else if (whole == bdev)
547+ return true; /* is a whole device which isn't held */
548+
549+ else if (whole->bd_holder == bd_may_claim)
550+ return true; /* is a partition of a device that is being partitioned */
551+ else if (whole->bd_holder != NULL)
552+ return false; /* is a partition of a held device */
553+ else
554+ return true; /* is a partition of an un-held device */
555+}
556+
557+/**
558+ * bd_prepare_to_claim - claim a block device
559+ * @bdev: block device of interest
560+ * @holder: holder trying to claim @bdev
561+ *
562+ * Claim @bdev. This function fails if @bdev is already claimed by another
563+ * holder and waits if another claiming is in progress. return, the caller
564+ * has ownership of bd_claiming and bd_holder[s].
565+ *
566+ * RETURNS:
567+ * 0 if @bdev can be claimed, -EBUSY otherwise.
568+ */
569+int bd_prepare_to_claim(struct block_device *bdev, void *holder)
570+{
571+ struct block_device *whole = bdev_whole(bdev);
572+
573+ if (WARN_ON_ONCE(!holder))
574+ return -EINVAL;
575+retry:
576+ spin_lock(&bdev_lock);
577+ /* if someone else claimed, fail */
578+ if (!bd_may_claim(bdev, whole, holder)) {
579+ spin_unlock(&bdev_lock);
580+ return -EBUSY;
581+ }
582+
583+ /* if claiming is already in progress, wait for it to finish */
584+ if (whole->bd_claiming) {
585+ wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0);
586+ DEFINE_WAIT(wait);
587+
588+ prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
589+ spin_unlock(&bdev_lock);
590+ schedule();
591+ finish_wait(wq, &wait);
592+ goto retry;
593+ }
594+
595+ /* yay, all mine */
596+ whole->bd_claiming = holder;
597+ spin_unlock(&bdev_lock);
598+ return 0;
599+}
600+EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */
601+
602+static void bd_clear_claiming(struct block_device *whole, void *holder)
603+{
604+ lockdep_assert_held(&bdev_lock);
605+ /* tell others that we're done */
606+ BUG_ON(whole->bd_claiming != holder);
607+ whole->bd_claiming = NULL;
608+ wake_up_bit(&whole->bd_claiming, 0);
609+}
610+
611+/**
612+ * bd_finish_claiming - finish claiming of a block device
613+ * @bdev: block device of interest
614+ * @holder: holder that has claimed @bdev
615+ *
616+ * Finish exclusive open of a block device. Mark the device as exlusively
617+ * open by the holder and wake up all waiters for exclusive open to finish.
618+ */
619+static void bd_finish_claiming(struct block_device *bdev, void *holder)
620+{
621+ struct block_device *whole = bdev_whole(bdev);
622+
623+ spin_lock(&bdev_lock);
624+ BUG_ON(!bd_may_claim(bdev, whole, holder));
625+ /*
626+ * Note that for a whole device bd_holders will be incremented twice,
627+ * and bd_holder will be set to bd_may_claim before being set to holder
628+ */
629+ whole->bd_holders++;
630+ whole->bd_holder = bd_may_claim;
631+ bdev->bd_holders++;
632+ bdev->bd_holder = holder;
633+ bd_clear_claiming(whole, holder);
634+ spin_unlock(&bdev_lock);
635+}
636+
637+/**
638+ * bd_abort_claiming - abort claiming of a block device
639+ * @bdev: block device of interest
640+ * @holder: holder that has claimed @bdev
641+ *
642+ * Abort claiming of a block device when the exclusive open failed. This can be
643+ * also used when exclusive open is not actually desired and we just needed
644+ * to block other exclusive openers for a while.
645+ */
646+void bd_abort_claiming(struct block_device *bdev, void *holder)
647+{
648+ spin_lock(&bdev_lock);
649+ bd_clear_claiming(bdev_whole(bdev), holder);
650+ spin_unlock(&bdev_lock);
651+}
652+EXPORT_SYMBOL(bd_abort_claiming);
653+
654+static void blkdev_flush_mapping(struct block_device *bdev)
655+{
656+ WARN_ON_ONCE(bdev->bd_holders);
657+ sync_blockdev(bdev);
658+ kill_bdev(bdev);
659+ bdev_write_inode(bdev);
660+}
661+
662+static int blkdev_get_whole(struct block_device *bdev, fmode_t mode)
663+{
664+ struct gendisk *disk = bdev->bd_disk;
665+ int ret = 0;
666+
667+ if (disk->fops->open) {
668+ ret = disk->fops->open(bdev, mode);
669+ if (ret) {
670+ /* avoid ghost partitions on a removed medium */
671+ if (ret == -ENOMEDIUM &&
672+ test_bit(GD_NEED_PART_SCAN, &disk->state))
673+ bdev_disk_changed(disk, true);
674+ return ret;
675+ }
676+ }
677+
678+ if (!bdev->bd_openers)
679+ set_init_blocksize(bdev);
680+ if (test_bit(GD_NEED_PART_SCAN, &disk->state))
681+ bdev_disk_changed(disk, false);
682+ bdev->bd_openers++;
683+ return 0;;
684+}
685+
686+static void blkdev_put_whole(struct block_device *bdev, fmode_t mode)
687+{
688+ if (!--bdev->bd_openers)
689+ blkdev_flush_mapping(bdev);
690+ if (bdev->bd_disk->fops->release)
691+ bdev->bd_disk->fops->release(bdev->bd_disk, mode);
692+}
693+
694+static int blkdev_get_part(struct block_device *part, fmode_t mode)
695+{
696+ struct gendisk *disk = part->bd_disk;
697+ int ret;
698+
699+ if (part->bd_openers)
700+ goto done;
701+
702+ ret = blkdev_get_whole(bdev_whole(part), mode);
703+ if (ret)
704+ return ret;
705+
706+ ret = -ENXIO;
707+ if (!bdev_nr_sectors(part))
708+ goto out_blkdev_put;
709+
710+ disk->open_partitions++;
711+ set_init_blocksize(part);
712+done:
713+ part->bd_openers++;
714+ return 0;
715+
716+out_blkdev_put:
717+ blkdev_put_whole(bdev_whole(part), mode);
718+ return ret;
719+}
720+
721+static void blkdev_put_part(struct block_device *part, fmode_t mode)
722+{
723+ struct block_device *whole = bdev_whole(part);
724+
725+ if (--part->bd_openers)
726+ return;
727+ blkdev_flush_mapping(part);
728+ whole->bd_disk->open_partitions--;
729+ blkdev_put_whole(whole, mode);
730+}
731+
732+struct block_device *blkdev_get_no_open(dev_t dev)
733+{
734+ struct block_device *bdev;
735+ struct inode *inode;
736+
737+ inode = ilookup(blockdev_superblock, dev);
738+ if (!inode) {
739+ blk_request_module(dev);
740+ inode = ilookup(blockdev_superblock, dev);
741+ if (!inode)
742+ return NULL;
743+ }
744+
745+ /* switch from the inode reference to a device mode one: */
746+ bdev = &BDEV_I(inode)->bdev;
747+ if (!kobject_get_unless_zero(&bdev->bd_device.kobj))
748+ bdev = NULL;
749+ iput(inode);
750+
751+ if (!bdev)
752+ return NULL;
753+ if ((bdev->bd_disk->flags & GENHD_FL_HIDDEN) ||
754+ !try_module_get(bdev->bd_disk->fops->owner)) {
755+ put_device(&bdev->bd_device);
756+ return NULL;
757+ }
758+
759+ return bdev;
760+}
761+
762+void blkdev_put_no_open(struct block_device *bdev)
763+{
764+ module_put(bdev->bd_disk->fops->owner);
765+ put_device(&bdev->bd_device);
766+}
767+
768+/**
769+ * blkdev_get_by_dev - open a block device by device number
770+ * @dev: device number of block device to open
771+ * @mode: FMODE_* mask
772+ * @holder: exclusive holder identifier
773+ *
774+ * Open the block device described by device number @dev. If @mode includes
775+ * %FMODE_EXCL, the block device is opened with exclusive access. Specifying
776+ * %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may nest for
777+ * the same @holder.
778+ *
779+ * Use this interface ONLY if you really do not have anything better - i.e. when
780+ * you are behind a truly sucky interface and all you are given is a device
781+ * number. Everything else should use blkdev_get_by_path().
782+ *
783+ * CONTEXT:
784+ * Might sleep.
785+ *
786+ * RETURNS:
787+ * Reference to the block_device on success, ERR_PTR(-errno) on failure.
788+ */
789+struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
790+{
791+ bool unblock_events = true;
792+ struct block_device *bdev;
793+ struct gendisk *disk;
794+ int ret;
795+
796+ ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
797+ MAJOR(dev), MINOR(dev),
798+ ((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) |
799+ ((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0));
800+ if (ret)
801+ return ERR_PTR(ret);
802+
803+ bdev = blkdev_get_no_open(dev);
804+ if (!bdev)
805+ return ERR_PTR(-ENXIO);
806+ disk = bdev->bd_disk;
807+
808+ if (mode & FMODE_EXCL) {
809+ ret = bd_prepare_to_claim(bdev, holder);
810+ if (ret)
811+ goto put_blkdev;
812+ }
813+
814+ disk_block_events(disk);
815+
816+ mutex_lock(&disk->open_mutex);
817+ ret = -ENXIO;
818+ if (!disk_live(disk))
819+ goto abort_claiming;
820+ if (bdev_is_partition(bdev))
821+ ret = blkdev_get_part(bdev, mode);
822+ else
823+ ret = blkdev_get_whole(bdev, mode);
824+ if (ret)
825+ goto abort_claiming;
826+ if (mode & FMODE_EXCL) {
827+ bd_finish_claiming(bdev, holder);
828+
829+ /*
830+ * Block event polling for write claims if requested. Any write
831+ * holder makes the write_holder state stick until all are
832+ * released. This is good enough and tracking individual
833+ * writeable reference is too fragile given the way @mode is
834+ * used in blkdev_get/put().
835+ */
836+ if ((mode & FMODE_WRITE) && !bdev->bd_write_holder &&
837+ (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
838+ bdev->bd_write_holder = true;
839+ unblock_events = false;
840+ }
841+ }
842+ mutex_unlock(&disk->open_mutex);
843+
844+ if (unblock_events)
845+ disk_unblock_events(disk);
846+ return bdev;
847+
848+abort_claiming:
849+ if (mode & FMODE_EXCL)
850+ bd_abort_claiming(bdev, holder);
851+ mutex_unlock(&disk->open_mutex);
852+ disk_unblock_events(disk);
853+put_blkdev:
854+ blkdev_put_no_open(bdev);
855+ return ERR_PTR(ret);
856+}
857+EXPORT_SYMBOL(blkdev_get_by_dev);
858+
859+/**
860+ * blkdev_get_by_path - open a block device by name
861+ * @path: path to the block device to open
862+ * @mode: FMODE_* mask
863+ * @holder: exclusive holder identifier
864+ *
865+ * Open the block device described by the device file at @path. If @mode
866+ * includes %FMODE_EXCL, the block device is opened with exclusive access.
867+ * Specifying %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may
868+ * nest for the same @holder.
869+ *
870+ * CONTEXT:
871+ * Might sleep.
872+ *
873+ * RETURNS:
874+ * Reference to the block_device on success, ERR_PTR(-errno) on failure.
875+ */
876+struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
877+ void *holder)
878+{
879+ struct block_device *bdev;
880+ dev_t dev;
881+ int error;
882+
883+ error = lookup_bdev(path, &dev);
884+ if (error)
885+ return ERR_PTR(error);
886+
887+ bdev = blkdev_get_by_dev(dev, mode, holder);
888+ if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) {
889+ blkdev_put(bdev, mode);
890+ return ERR_PTR(-EACCES);
891+ }
892+
893+ return bdev;
894+}
895+EXPORT_SYMBOL(blkdev_get_by_path);
896+
897+void blkdev_put(struct block_device *bdev, fmode_t mode)
898+{
899+ struct gendisk *disk = bdev->bd_disk;
900+
901+ /*
902+ * Sync early if it looks like we're the last one. If someone else
903+ * opens the block device between now and the decrement of bd_openers
904+ * then we did a sync that we didn't need to, but that's not the end
905+ * of the world and we want to avoid long (could be several minute)
906+ * syncs while holding the mutex.
907+ */
908+ if (bdev->bd_openers == 1)
909+ sync_blockdev(bdev);
910+
911+ mutex_lock(&disk->open_mutex);
912+ if (mode & FMODE_EXCL) {
913+ struct block_device *whole = bdev_whole(bdev);
914+ bool bdev_free;
915+
916+ /*
917+ * Release a claim on the device. The holder fields
918+ * are protected with bdev_lock. open_mutex is to
919+ * synchronize disk_holder unlinking.
920+ */
921+ spin_lock(&bdev_lock);
922+
923+ WARN_ON_ONCE(--bdev->bd_holders < 0);
924+ WARN_ON_ONCE(--whole->bd_holders < 0);
925+
926+ if ((bdev_free = !bdev->bd_holders))
927+ bdev->bd_holder = NULL;
928+ if (!whole->bd_holders)
929+ whole->bd_holder = NULL;
930+
931+ spin_unlock(&bdev_lock);
932+
933+ /*
934+ * If this was the last claim, remove holder link and
935+ * unblock evpoll if it was a write holder.
936+ */
937+ if (bdev_free && bdev->bd_write_holder) {
938+ disk_unblock_events(disk);
939+ bdev->bd_write_holder = false;
940+ }
941+ }
942+
943+ /*
944+ * Trigger event checking and tell drivers to flush MEDIA_CHANGE
945+ * event. This is to ensure detection of media removal commanded
946+ * from userland - e.g. eject(1).
947+ */
948+ disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE);
949+
950+ if (bdev_is_partition(bdev))
951+ blkdev_put_part(bdev, mode);
952+ else
953+ blkdev_put_whole(bdev, mode);
954+ mutex_unlock(&disk->open_mutex);
955+
956+ blkdev_put_no_open(bdev);
957+}
958+EXPORT_SYMBOL(blkdev_put);
959+
960+/**
961+ * lookup_bdev - lookup a struct block_device by name
962+ * @pathname: special file representing the block device
963+ * @dev: return value of the block device's dev_t
964+ *
965+ * Get a reference to the blockdevice at @pathname in the current
966+ * namespace if possible and return it. Return ERR_PTR(error)
967+ * otherwise.
968+ */
969+int lookup_bdev(const char *pathname, dev_t *dev)
970+{
971+ struct inode *inode;
972+ struct path path;
973+ int error;
974+
975+ if (!pathname || !*pathname)
976+ return -EINVAL;
977+
978+ error = kern_path(pathname, LOOKUP_FOLLOW, &path);
979+ if (error)
980+ return error;
981+
982+ inode = d_backing_inode(path.dentry);
983+ error = -ENOTBLK;
984+ if (!S_ISBLK(inode->i_mode))
985+ goto out_path_put;
986+ error = -EACCES;
987+ if (!may_open_dev(&path))
988+ goto out_path_put;
989+
990+ *dev = inode->i_rdev;
991+ error = 0;
992+out_path_put:
993+ path_put(&path);
994+ return error;
995+}
996+EXPORT_SYMBOL(lookup_bdev);
997+
998+int __invalidate_device(struct block_device *bdev, bool kill_dirty)
999+{
1000+ struct super_block *sb = get_super(bdev);
1001+ int res = 0;
1002+
1003+ if (sb) {
1004+ /*
1005+ * no need to lock the super, get_super holds the
1006+ * read mutex so the filesystem cannot go away
1007+ * under us (->put_super runs with the write lock
1008+ * hold).
1009+ */
1010+ shrink_dcache_sb(sb);
1011+ res = invalidate_inodes(sb, kill_dirty);
1012+ drop_super(sb);
1013+ }
1014+ invalidate_bdev(bdev);
1015+ return res;
1016+}
1017+EXPORT_SYMBOL(__invalidate_device);
1018+
1019+void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg)
1020+{
1021+ struct inode *inode, *old_inode = NULL;
1022+
1023+ spin_lock(&blockdev_superblock->s_inode_list_lock);
1024+ list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) {
1025+ struct address_space *mapping = inode->i_mapping;
1026+ struct block_device *bdev;
1027+
1028+ spin_lock(&inode->i_lock);
1029+ if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) ||
1030+ mapping->nrpages == 0) {
1031+ spin_unlock(&inode->i_lock);
1032+ continue;
1033+ }
1034+ __iget(inode);
1035+ spin_unlock(&inode->i_lock);
1036+ spin_unlock(&blockdev_superblock->s_inode_list_lock);
1037+ /*
1038+ * We hold a reference to 'inode' so it couldn't have been
1039+ * removed from s_inodes list while we dropped the
1040+ * s_inode_list_lock We cannot iput the inode now as we can
1041+ * be holding the last reference and we cannot iput it under
1042+ * s_inode_list_lock. So we keep the reference and iput it
1043+ * later.
1044+ */
1045+ iput(old_inode);
1046+ old_inode = inode;
1047+ bdev = I_BDEV(inode);
1048+
1049+ mutex_lock(&bdev->bd_disk->open_mutex);
1050+ if (bdev->bd_openers)
1051+ func(bdev, arg);
1052+ mutex_unlock(&bdev->bd_disk->open_mutex);
1053+
1054+ spin_lock(&blockdev_superblock->s_inode_list_lock);
1055+ }
1056+ spin_unlock(&blockdev_superblock->s_inode_list_lock);
1057+ iput(old_inode);
1058+}