// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 1991, 1992 Linus Torvalds * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE * Copyright (C) 2016 - 2020 Christoph Hellwig */ #include <linux/init.h> #include <linux/mm.h> #include <linux/slab.h> #include <linux/kmod.h> #include <linux/major.h> #include <linux/device_cgroup.h> #include <linux/blkdev.h> #include <linux/blk-integrity.h> #include <linux/backing-dev.h> #include <linux/module.h> #include <linux/blkpg.h> #include <linux/magic.h> #include <linux/buffer_head.h> #include <linux/swap.h> #include <linux/writeback.h> #include <linux/mount.h> #include <linux/pseudo_fs.h> #include <linux/uio.h> #include <linux/namei.h> #include <linux/part_stat.h> #include <linux/uaccess.h> #include <linux/stat.h> #include "../fs/internal.h" #include "blk.h" struct bdev_inode { struct block_device bdev; struct inode vfs_inode; }; static inline struct bdev_inode *BDEV_I(struct inode *inode) { return container_of(inode, struct bdev_inode, vfs_inode); } struct block_device *I_BDEV(struct inode *inode) { return &BDEV_I(inode)->bdev; } EXPORT_SYMBOL(I_BDEV); static void bdev_write_inode(struct block_device *bdev) { struct inode *inode = bdev->bd_inode; int ret; spin_lock(&inode->i_lock); while (inode->i_state & I_DIRTY) { spin_unlock(&inode->i_lock); ret = write_inode_now(inode, true); if (ret) pr_warn_ratelimited( "VFS: Dirty inode writeback failed for block device %pg (err=%d).\n", bdev, ret); spin_lock(&inode->i_lock); } spin_unlock(&inode->i_lock); } /* Kill _all_ buffers and pagecache , dirty or not.. */ static void kill_bdev(struct block_device *bdev) { struct address_space *mapping = bdev->bd_inode->i_mapping; if (mapping_empty(mapping)) return; invalidate_bh_lrus(); truncate_inode_pages(mapping, 0); } /* Invalidate clean unused buffers and pagecache. */ void invalidate_bdev(struct block_device *bdev) { struct address_space *mapping = bdev->bd_inode->i_mapping; if (mapping->nrpages) { invalidate_bh_lrus(); lru_add_drain_all(); /* make sure all lru add caches are flushed */ invalidate_mapping_pages(mapping, 0, -1); } } EXPORT_SYMBOL(invalidate_bdev); /* * Drop all buffers & page cache for given bdev range. This function bails * with error if bdev has other exclusive owner (such as filesystem). */ int truncate_bdev_range(struct block_device *bdev, fmode_t mode, loff_t lstart, loff_t lend) { /* * If we don't hold exclusive handle for the device, upgrade to it * while we discard the buffer cache to avoid discarding buffers * under live filesystem. */ if (!(mode & FMODE_EXCL)) { int err = bd_prepare_to_claim(bdev, truncate_bdev_range); if (err) goto invalidate; } truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend); if (!(mode & FMODE_EXCL)) bd_abort_claiming(bdev, truncate_bdev_range); return 0; invalidate: /* * Someone else has handle exclusively open. Try invalidating instead. * The 'end' argument is inclusive so the rounding is safe. */ return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping, lstart >> PAGE_SHIFT, lend >> PAGE_SHIFT); } static void set_init_blocksize(struct block_device *bdev) { unsigned int bsize = bdev_logical_block_size(bdev); loff_t size = i_size_read(bdev->bd_inode); while (bsize < PAGE_SIZE) { if (size & bsize) break; bsize <<= 1; } bdev->bd_inode->i_blkbits = blksize_bits(bsize); } int set_blocksize(struct block_device *bdev, int size) { /* Size must be a power of two, and between 512 and PAGE_SIZE */ if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) return -EINVAL; /* Size cannot be smaller than the size supported by the device */ if (size < bdev_logical_block_size(bdev)) return -EINVAL; /* Don't change the size if it is same as current */ if (bdev->bd_inode->i_blkbits != blksize_bits(size)) { sync_blockdev(bdev); bdev->bd_inode->i_blkbits = blksize_bits(size); kill_bdev(bdev); } return 0; } EXPORT_SYMBOL(set_blocksize); int sb_set_blocksize(struct super_block *sb, int size) { if (set_blocksize(sb->s_bdev, size)) return 0; /* If we get here, we know size is power of two * and it's value is between 512 and PAGE_SIZE */ sb->s_blocksize = size; sb->s_blocksize_bits = blksize_bits(size); return sb->s_blocksize; } EXPORT_SYMBOL(sb_set_blocksize); int sb_min_blocksize(struct super_block *sb, int size) { int minsize = bdev_logical_block_size(sb->s_bdev); if (size < minsize) size = minsize; return sb_set_blocksize(sb, size); } EXPORT_SYMBOL(sb_min_blocksize); int sync_blockdev_nowait(struct block_device *bdev) { if (!bdev) return 0; return filemap_flush(bdev->bd_inode->i_mapping); } EXPORT_SYMBOL_GPL(sync_blockdev_nowait); /* * Write out and wait upon all the dirty data associated with a block * device via its mapping. Does not take the superblock lock. */ int sync_blockdev(struct block_device *bdev) { if (!bdev) return 0; return filemap_write_and_wait(bdev->bd_inode->i_mapping); } EXPORT_SYMBOL(sync_blockdev); int sync_blockdev_range(struct block_device *bdev, loff_t lstart, loff_t lend) { return filemap_write_and_wait_range(bdev->bd_inode->i_mapping, lstart, lend); } EXPORT_SYMBOL(sync_blockdev_range); /* * Write out and wait upon all dirty data associated with this * device. Filesystem data as well as the underlying block * device. Takes the superblock lock. */ int fsync_bdev(struct block_device *bdev) { struct super_block *sb = get_super(bdev); if (sb) { int res = sync_filesystem(sb); drop_super(sb); return res; } return sync_blockdev(bdev); } EXPORT_SYMBOL(fsync_bdev); /** * freeze_bdev - lock a filesystem and force it into a consistent state * @bdev: blockdevice to lock * * If a superblock is found on this device, we take the s_umount semaphore * on it to make sure nobody unmounts until the snapshot creation is done. * The reference counter (bd_fsfreeze_count) guarantees that only the last * unfreeze process can unfreeze the frozen filesystem actually when multiple * freeze requests arrive simultaneously. It counts up in freeze_bdev() and * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze * actually. */ int freeze_bdev(struct block_device *bdev) { struct super_block *sb; int error = 0; mutex_lock(&bdev->bd_fsfreeze_mutex); if (++bdev->bd_fsfreeze_count > 1) goto done; sb = get_active_super(bdev); if (!sb) goto sync; if (sb->s_op->freeze_super) error = sb->s_op->freeze_super(sb); else error = freeze_super(sb); deactivate_super(sb); if (error) { bdev->bd_fsfreeze_count--; goto done; } bdev->bd_fsfreeze_sb = sb; sync: sync_blockdev(bdev); done: mutex_unlock(&bdev->bd_fsfreeze_mutex); return error; } EXPORT_SYMBOL(freeze_bdev); /** * thaw_bdev - unlock filesystem * @bdev: blockdevice to unlock * * Unlocks the filesystem and marks it writeable again after freeze_bdev(). */ int thaw_bdev(struct block_device *bdev) { struct super_block *sb; int error = -EINVAL; mutex_lock(&bdev->bd_fsfreeze_mutex); if (!bdev->bd_fsfreeze_count) goto out; error = 0; if (--bdev->bd_fsfreeze_count > 0) goto out; sb = bdev->bd_fsfreeze_sb; if (!sb) goto out; if (sb->s_op->thaw_super) error = sb->s_op->thaw_super(sb); else error = thaw_super(sb); if (error) bdev->bd_fsfreeze_count++; else bdev->bd_fsfreeze_sb = NULL; out: mutex_unlock(&bdev->bd_fsfreeze_mutex); return error; } EXPORT_SYMBOL(thaw_bdev); /* * pseudo-fs */ static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); static struct kmem_cache * bdev_cachep __read_mostly; static struct inode *bdev_alloc_inode(struct super_block *sb) { struct bdev_inode *ei = alloc_inode_sb(sb, bdev_cachep, GFP_KERNEL); if (!ei) return NULL; memset(&ei->bdev, 0, sizeof(ei->bdev)); return &ei->vfs_inode; } static void bdev_free_inode(struct inode *inode) { struct block_device *bdev = I_BDEV(inode); free_percpu(bdev->bd_stats); kfree(bdev->bd_meta_info); if (!bdev_is_partition(bdev)) { if (bdev->bd_disk && bdev->bd_disk->bdi) bdi_put(bdev->bd_disk->bdi); kfree(bdev->bd_disk); } if (MAJOR(bdev->bd_dev) == BLOCK_EXT_MAJOR) blk_free_ext_minor(MINOR(bdev->bd_dev)); kmem_cache_free(bdev_cachep, BDEV_I(inode)); } static void init_once(void *data) { struct bdev_inode *ei = data; inode_init_once(&ei->vfs_inode); } static void bdev_evict_inode(struct inode *inode) { truncate_inode_pages_final(&inode->i_data); invalidate_inode_buffers(inode); /* is it needed here? */ clear_inode(inode); } static const struct super_operations bdev_sops = { .statfs = simple_statfs, .alloc_inode = bdev_alloc_inode, .free_inode = bdev_free_inode, .drop_inode = generic_delete_inode, .evict_inode = bdev_evict_inode, }; static int bd_init_fs_context(struct fs_context *fc) { struct pseudo_fs_context *ctx = init_pseudo(fc, BDEVFS_MAGIC); if (!ctx) return -ENOMEM; fc->s_iflags |= SB_I_CGROUPWB; ctx->ops = &bdev_sops; return 0; } static struct file_system_type bd_type = { .name = "bdev", .init_fs_context = bd_init_fs_context, .kill_sb = kill_anon_super, }; struct super_block *blockdev_superblock __read_mostly; EXPORT_SYMBOL_GPL(blockdev_superblock); void __init bdev_cache_init(void) { int err; static struct vfsmount *bd_mnt; bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC), init_once); err = register_filesystem(&bd_type); if (err) panic("Cannot register bdev pseudo-fs"); bd_mnt = kern_mount(&bd_type); if (IS_ERR(bd_mnt)) panic("Cannot create bdev pseudo-fs"); blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ } struct block_device *bdev_alloc(struct gendisk *disk, u8 partno) { struct block_device *bdev; struct inode *inode; inode = new_inode(blockdev_superblock); if (!inode) return NULL; inode->i_mode = S_IFBLK; inode->i_rdev = 0; inode->i_data.a_ops = &def_blk_aops; mapping_set_gfp_mask(&inode->i_data, GFP_USER); bdev = I_BDEV(inode); mutex_init(&bdev->bd_fsfreeze_mutex); spin_lock_init(&bdev->bd_size_lock); bdev->bd_partno = partno; bdev->bd_inode = inode; bdev->bd_queue = disk->queue; if (partno) bdev->bd_has_submit_bio = disk->part0->bd_has_submit_bio; else bdev->bd_has_submit_bio = false; bdev->bd_stats = alloc_percpu(struct disk_stats); if (!bdev->bd_stats) { iput(inode); return NULL; } bdev->bd_disk = disk; return bdev; } void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors) { spin_lock(&bdev->bd_size_lock); i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT); bdev->bd_nr_sectors = sectors; spin_unlock(&bdev->bd_size_lock); } void bdev_add(struct block_device *bdev, dev_t dev) { bdev->bd_dev = dev; bdev->bd_inode->i_rdev = dev; bdev->bd_inode->i_ino = dev; insert_inode_hash(bdev->bd_inode); } long nr_blockdev_pages(void) { struct inode *inode; long ret = 0; spin_lock(&blockdev_superblock->s_inode_list_lock); list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) ret += inode->i_mapping->nrpages; spin_unlock(&blockdev_superblock->s_inode_list_lock); return ret; } /** * bd_may_claim - test whether a block device can be claimed * @bdev: block device of interest * @whole: whole block device containing @bdev, may equal @bdev * @holder: holder trying to claim @bdev * * Test whether @bdev can be claimed by @holder. * * CONTEXT: * spin_lock(&bdev_lock). * * RETURNS: * %true if @bdev can be claimed, %false otherwise. */ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, void *holder) { if (bdev->bd_holder == holder) return true; /* already a holder */ else if (bdev->bd_holder != NULL) return false; /* held by someone else */ else if (whole == bdev) return true; /* is a whole device which isn't held */ else if (whole->bd_holder == bd_may_claim) return true; /* is a partition of a device that is being partitioned */ else if (whole->bd_holder != NULL) return false; /* is a partition of a held device */ else return true; /* is a partition of an un-held device */ } /** * bd_prepare_to_claim - claim a block device * @bdev: block device of interest * @holder: holder trying to claim @bdev * * Claim @bdev. This function fails if @bdev is already claimed by another * holder and waits if another claiming is in progress. return, the caller * has ownership of bd_claiming and bd_holder[s]. * * RETURNS: * 0 if @bdev can be claimed, -EBUSY otherwise. */ int bd_prepare_to_claim(struct block_device *bdev, void *holder) { struct block_device *whole = bdev_whole(bdev); if (WARN_ON_ONCE(!holder)) return -EINVAL; retry: spin_lock(&bdev_lock); /* if someone else claimed, fail */ if (!bd_may_claim(bdev, whole, holder)) { spin_unlock(&bdev_lock); return -EBUSY; } /* if claiming is already in progress, wait for it to finish */ if (whole->bd_claiming) { wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0); DEFINE_WAIT(wait); prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); spin_unlock(&bdev_lock); schedule(); finish_wait(wq, &wait); goto retry; } /* yay, all mine */ whole->bd_claiming = holder; spin_unlock(&bdev_lock); return 0; } EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */ static void bd_clear_claiming(struct block_device *whole, void *holder) { lockdep_assert_held(&bdev_lock); /* tell others that we're done */ BUG_ON(whole->bd_claiming != holder); whole->bd_claiming = NULL; wake_up_bit(&whole->bd_claiming, 0); } /** * bd_finish_claiming - finish claiming of a block device * @bdev: block device of interest * @holder: holder that has claimed @bdev * * Finish exclusive open of a block device. Mark the device as exlusively * open by the holder and wake up all waiters for exclusive open to finish. */ static void bd_finish_claiming(struct block_device *bdev, void *holder) { struct block_device *whole = bdev_whole(bdev); spin_lock(&bdev_lock); BUG_ON(!bd_may_claim(bdev, whole, holder)); /* * Note that for a whole device bd_holders will be incremented twice, * and bd_holder will be set to bd_may_claim before being set to holder */ whole->bd_holders++; whole->bd_holder = bd_may_claim; bdev->bd_holders++; bdev->bd_holder = holder; bd_clear_claiming(whole, holder); spin_unlock(&bdev_lock); } /** * bd_abort_claiming - abort claiming of a block device * @bdev: block device of interest * @holder: holder that has claimed @bdev * * Abort claiming of a block device when the exclusive open failed. This can be * also used when exclusive open is not actually desired and we just needed * to block other exclusive openers for a while. */ void bd_abort_claiming(struct block_device *bdev, void *holder) { spin_lock(&bdev_lock); bd_clear_claiming(bdev_whole(bdev), holder); spin_unlock(&bdev_lock); } EXPORT_SYMBOL(bd_abort_claiming); static void blkdev_flush_mapping(struct block_device *bdev) { WARN_ON_ONCE(bdev->bd_holders); sync_blockdev(bdev); kill_bdev(bdev); bdev_write_inode(bdev); } static int blkdev_get_whole(struct block_device *bdev, fmode_t mode) { struct gendisk *disk = bdev->bd_disk; int ret; if (disk->fops->open) { ret = disk->fops->open(bdev, mode); if (ret) { /* avoid ghost partitions on a removed medium */ if (ret == -ENOMEDIUM && test_bit(GD_NEED_PART_SCAN, &disk->state)) bdev_disk_changed(disk, true); return ret; } } if (!atomic_read(&bdev->bd_openers)) set_init_blocksize(bdev); if (test_bit(GD_NEED_PART_SCAN, &disk->state)) bdev_disk_changed(disk, false); atomic_inc(&bdev->bd_openers); return 0; } static void blkdev_put_whole(struct block_device *bdev, fmode_t mode) { if (atomic_dec_and_test(&bdev->bd_openers)) blkdev_flush_mapping(bdev); if (bdev->bd_disk->fops->release) bdev->bd_disk->fops->release(bdev->bd_disk, mode); } static int blkdev_get_part(struct block_device *part, fmode_t mode) { struct gendisk *disk = part->bd_disk; int ret; if (atomic_read(&part->bd_openers)) goto done; ret = blkdev_get_whole(bdev_whole(part), mode); if (ret) return ret; ret = -ENXIO; if (!bdev_nr_sectors(part)) goto out_blkdev_put; disk->open_partitions++; set_init_blocksize(part); done: atomic_inc(&part->bd_openers); return 0; out_blkdev_put: blkdev_put_whole(bdev_whole(part), mode); return ret; } static void blkdev_put_part(struct block_device *part, fmode_t mode) { struct block_device *whole = bdev_whole(part); if (!atomic_dec_and_test(&part->bd_openers)) return; blkdev_flush_mapping(part); whole->bd_disk->open_partitions--; blkdev_put_whole(whole, mode); } struct block_device *blkdev_get_no_open(dev_t dev) { struct block_device *bdev; struct inode *inode; inode = ilookup(blockdev_superblock, dev); if (!inode && IS_ENABLED(CONFIG_BLOCK_LEGACY_AUTOLOAD)) { blk_request_module(dev); inode = ilookup(blockdev_superblock, dev); if (inode) pr_warn_ratelimited( "block device autoloading is deprecated and will be removed.\n"); } if (!inode) return NULL; /* switch from the inode reference to a device mode one: */ bdev = &BDEV_I(inode)->bdev; if (!kobject_get_unless_zero(&bdev->bd_device.kobj)) bdev = NULL; iput(inode); return bdev; } void blkdev_put_no_open(struct block_device *bdev) { put_device(&bdev->bd_device); } /** * blkdev_get_by_dev - open a block device by device number * @dev: device number of block device to open * @mode: FMODE_* mask * @holder: exclusive holder identifier * * Open the block device described by device number @dev. If @mode includes * %FMODE_EXCL, the block device is opened with exclusive access. Specifying * %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may nest for * the same @holder. * * Use this interface ONLY if you really do not have anything better - i.e. when * you are behind a truly sucky interface and all you are given is a device * number. Everything else should use blkdev_get_by_path(). * * CONTEXT: * Might sleep. * * RETURNS: * Reference to the block_device on success, ERR_PTR(-errno) on failure. */ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) { bool unblock_events = true; struct block_device *bdev; struct gendisk *disk; int ret; ret = devcgroup_check_permission(DEVCG_DEV_BLOCK, MAJOR(dev), MINOR(dev), ((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) | ((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0)); if (ret) return ERR_PTR(ret); bdev = blkdev_get_no_open(dev); if (!bdev) return ERR_PTR(-ENXIO); disk = bdev->bd_disk; if (mode & FMODE_EXCL) { ret = bd_prepare_to_claim(bdev, holder); if (ret) goto put_blkdev; } disk_block_events(disk); mutex_lock(&disk->open_mutex); ret = -ENXIO; if (!disk_live(disk)) goto abort_claiming; if (!try_module_get(disk->fops->owner)) goto abort_claiming; if (bdev_is_partition(bdev)) ret = blkdev_get_part(bdev, mode); else ret = blkdev_get_whole(bdev, mode); if (ret) goto put_module; if (mode & FMODE_EXCL) { bd_finish_claiming(bdev, holder); /* * Block event polling for write claims if requested. Any write * holder makes the write_holder state stick until all are * released. This is good enough and tracking individual * writeable reference is too fragile given the way @mode is * used in blkdev_get/put(). */ if ((mode & FMODE_WRITE) && !bdev->bd_write_holder && (disk->event_flags & DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE)) { bdev->bd_write_holder = true; unblock_events = false; } } mutex_unlock(&disk->open_mutex); if (unblock_events) disk_unblock_events(disk); return bdev; put_module: module_put(disk->fops->owner); abort_claiming: if (mode & FMODE_EXCL) bd_abort_claiming(bdev, holder); mutex_unlock(&disk->open_mutex); disk_unblock_events(disk); put_blkdev: blkdev_put_no_open(bdev); return ERR_PTR(ret); } EXPORT_SYMBOL(blkdev_get_by_dev); /** * blkdev_get_by_path - open a block device by name * @path: path to the block device to open * @mode: FMODE_* mask * @holder: exclusive holder identifier * * Open the block device described by the device file at @path. If @mode * includes %FMODE_EXCL, the block device is opened with exclusive access. * Specifying %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may * nest for the same @holder. * * CONTEXT: * Might sleep. * * RETURNS: * Reference to the block_device on success, ERR_PTR(-errno) on failure. */ struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, void *holder) { struct block_device *bdev; dev_t dev; int error; error = lookup_bdev(path, &dev); if (error) return ERR_PTR(error); bdev = blkdev_get_by_dev(dev, mode, holder); if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) { blkdev_put(bdev, mode); return ERR_PTR(-EACCES); } return bdev; } EXPORT_SYMBOL(blkdev_get_by_path); void blkdev_put(struct block_device *bdev, fmode_t mode) { struct gendisk *disk = bdev->bd_disk; /* * Sync early if it looks like we're the last one. If someone else * opens the block device between now and the decrement of bd_openers * then we did a sync that we didn't need to, but that's not the end * of the world and we want to avoid long (could be several minute) * syncs while holding the mutex. */ if (atomic_read(&bdev->bd_openers) == 1) sync_blockdev(bdev); mutex_lock(&disk->open_mutex); if (mode & FMODE_EXCL) { struct block_device *whole = bdev_whole(bdev); bool bdev_free; /* * Release a claim on the device. The holder fields * are protected with bdev_lock. open_mutex is to * synchronize disk_holder unlinking. */ spin_lock(&bdev_lock); WARN_ON_ONCE(--bdev->bd_holders < 0); WARN_ON_ONCE(--whole->bd_holders < 0); if ((bdev_free = !bdev->bd_holders)) bdev->bd_holder = NULL; if (!whole->bd_holders) whole->bd_holder = NULL; spin_unlock(&bdev_lock); /* * If this was the last claim, remove holder link and * unblock evpoll if it was a write holder. */ if (bdev_free && bdev->bd_write_holder) { disk_unblock_events(disk); bdev->bd_write_holder = false; } } /* * Trigger event checking and tell drivers to flush MEDIA_CHANGE * event. This is to ensure detection of media removal commanded * from userland - e.g. eject(1). */ disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE); if (bdev_is_partition(bdev)) blkdev_put_part(bdev, mode); else blkdev_put_whole(bdev, mode); mutex_unlock(&disk->open_mutex); module_put(disk->fops->owner); blkdev_put_no_open(bdev); } EXPORT_SYMBOL(blkdev_put); /** * lookup_bdev() - Look up a struct block_device by name. * @pathname: Name of the block device in the filesystem. * @dev: Pointer to the block device's dev_t, if found. * * Lookup the block device's dev_t at @pathname in the current * namespace if possible and return it in @dev. * * Context: May sleep. * Return: 0 if succeeded, negative errno otherwise. */ int lookup_bdev(const char *pathname, dev_t *dev) { struct inode *inode; struct path path; int error; if (!pathname || !*pathname) return -EINVAL; error = kern_path(pathname, LOOKUP_FOLLOW, &path); if (error) return error; inode = d_backing_inode(path.dentry); error = -ENOTBLK; if (!S_ISBLK(inode->i_mode)) goto out_path_put; error = -EACCES; if (!may_open_dev(&path)) goto out_path_put; *dev = inode->i_rdev; error = 0; out_path_put: path_put(&path); return error; } EXPORT_SYMBOL(lookup_bdev); int __invalidate_device(struct block_device *bdev, bool kill_dirty) { struct super_block *sb = get_super(bdev); int res = 0; if (sb) { /* * no need to lock the super, get_super holds the * read mutex so the filesystem cannot go away * under us (->put_super runs with the write lock * hold). */ shrink_dcache_sb(sb); res = invalidate_inodes(sb, kill_dirty); drop_super(sb); } invalidate_bdev(bdev); return res; } EXPORT_SYMBOL(__invalidate_device); void sync_bdevs(bool wait) { struct inode *inode, *old_inode = NULL; spin_lock(&blockdev_superblock->s_inode_list_lock); list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) { struct address_space *mapping = inode->i_mapping; struct block_device *bdev; spin_lock(&inode->i_lock); if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) || mapping->nrpages == 0) { spin_unlock(&inode->i_lock); continue; } __iget(inode); spin_unlock(&inode->i_lock); spin_unlock(&blockdev_superblock->s_inode_list_lock); /* * We hold a reference to 'inode' so it couldn't have been * removed from s_inodes list while we dropped the * s_inode_list_lock We cannot iput the inode now as we can * be holding the last reference and we cannot iput it under * s_inode_list_lock. So we keep the reference and iput it * later. */ iput(old_inode); old_inode = inode; bdev = I_BDEV(inode); mutex_lock(&bdev->bd_disk->open_mutex); if (!atomic_read(&bdev->bd_openers)) { ; /* skip */ } else if (wait) { /* * We keep the error status of individual mapping so * that applications can catch the writeback error using * fsync(2). See filemap_fdatawait_keep_errors() for * details. */ filemap_fdatawait_keep_errors(inode->i_mapping); } else { filemap_fdatawrite(inode->i_mapping); } mutex_unlock(&bdev->bd_disk->open_mutex); spin_lock(&blockdev_superblock->s_inode_list_lock); } spin_unlock(&blockdev_superblock->s_inode_list_lock); iput(old_inode); } /* * Handle STATX_DIOALIGN for block devices. * * Note that the inode passed to this is the inode of a block device node file, * not the block device's internal inode. Therefore it is *not* valid to use * I_BDEV() here; the block device has to be looked up by i_rdev instead. */ void bdev_statx_dioalign(struct inode *inode, struct kstat *stat) { struct block_device *bdev; bdev = blkdev_get_no_open(inode->i_rdev); if (!bdev) return; stat->dio_mem_align = bdev_dma_alignment(bdev) + 1; stat->dio_offset_align = bdev_logical_block_size(bdev); stat->result_mask |= STATX_DIOALIGN; blkdev_put_no_open(bdev); }