diff options
40 files changed, 1043 insertions, 629 deletions
diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst index 898d0b43109e..f8fe815ab1f3 100644 --- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -260,9 +260,11 @@ filesystem. The following members are defined: void (*evict_inode) (struct inode *); void (*put_super) (struct super_block *); int (*sync_fs)(struct super_block *sb, int wait); - int (*freeze_super) (struct super_block *); + int (*freeze_super) (struct super_block *sb, + enum freeze_holder who); int (*freeze_fs) (struct super_block *); - int (*thaw_super) (struct super_block *); + int (*thaw_super) (struct super_block *sb, + enum freeze_wholder who); int (*unfreeze_fs) (struct super_block *); int (*statfs) (struct dentry *, struct kstatfs *); int (*remount_fs) (struct super_block *, int *, char *); diff --git a/block/bdev.c b/block/bdev.c index 979e28a46b98..f3b13aa1b7d4 100644 --- a/block/bdev.c +++ b/block/bdev.c @@ -206,23 +206,6 @@ int sync_blockdev_range(struct block_device *bdev, loff_t lstart, loff_t 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 @@ -248,9 +231,9 @@ int freeze_bdev(struct block_device *bdev) if (!sb) goto sync; if (sb->s_op->freeze_super) - error = sb->s_op->freeze_super(sb); + error = sb->s_op->freeze_super(sb, FREEZE_HOLDER_USERSPACE); else - error = freeze_super(sb); + error = freeze_super(sb, FREEZE_HOLDER_USERSPACE); deactivate_super(sb); if (error) { @@ -291,9 +274,9 @@ int thaw_bdev(struct block_device *bdev) goto out; if (sb->s_op->thaw_super) - error = sb->s_op->thaw_super(sb); + error = sb->s_op->thaw_super(sb, FREEZE_HOLDER_USERSPACE); else - error = thaw_super(sb); + error = thaw_super(sb, FREEZE_HOLDER_USERSPACE); if (error) bdev->bd_fsfreeze_count++; else @@ -960,26 +943,38 @@ out_path_put: } EXPORT_SYMBOL(lookup_bdev); -int __invalidate_device(struct block_device *bdev, bool kill_dirty) +/** + * bdev_mark_dead - mark a block device as dead + * @bdev: block device to operate on + * @surprise: indicate a surprise removal + * + * Tell the file system that this devices or media is dead. If @surprise is set + * to %true the device or media is already gone, if not we are preparing for an + * orderly removal. + * + * This calls into the file system, which then typicall syncs out all dirty data + * and writes back inodes and then invalidates any cached data in the inodes on + * the file system. In addition we also invalidate the block device mapping. + */ +void bdev_mark_dead(struct block_device *bdev, bool surprise) { - struct super_block *sb = get_super(bdev); - int res = 0; + mutex_lock(&bdev->bd_holder_lock); + if (bdev->bd_holder_ops && bdev->bd_holder_ops->mark_dead) + bdev->bd_holder_ops->mark_dead(bdev, surprise); + else + sync_blockdev(bdev); + mutex_unlock(&bdev->bd_holder_lock); - 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); +#ifdef CONFIG_DASD_MODULE +/* + * Drivers should not use this directly, but the DASD driver has historically + * had a shutdown to offline mode that doesn't actually remove the gendisk + * that otherwise looks a lot like a safe device removal. + */ +EXPORT_SYMBOL_GPL(bdev_mark_dead); +#endif void sync_bdevs(bool wait) { diff --git a/block/disk-events.c b/block/disk-events.c index 0cfac464e6d1..422db8292d09 100644 --- a/block/disk-events.c +++ b/block/disk-events.c @@ -281,9 +281,7 @@ bool disk_check_media_change(struct gendisk *disk) if (!(events & DISK_EVENT_MEDIA_CHANGE)) return false; - if (__invalidate_device(disk->part0, true)) - pr_warn("VFS: busy inodes on changed media %s\n", - disk->disk_name); + bdev_mark_dead(disk->part0, true); set_bit(GD_NEED_PART_SCAN, &disk->state); return true; } @@ -294,25 +292,16 @@ EXPORT_SYMBOL(disk_check_media_change); * @disk: the disk which will raise the event * @events: the events to raise * - * Generate uevents for the disk. If DISK_EVENT_MEDIA_CHANGE is present, - * attempt to free all dentries and inodes and invalidates all block + * Should be called when the media changes for @disk. Generates a uevent + * and attempts to free all dentries and inodes and invalidates all block * device page cache entries in that case. - * - * Returns %true if DISK_EVENT_MEDIA_CHANGE was raised, or %false if not. */ -bool disk_force_media_change(struct gendisk *disk, unsigned int events) +void disk_force_media_change(struct gendisk *disk) { - disk_event_uevent(disk, events); - - if (!(events & DISK_EVENT_MEDIA_CHANGE)) - return false; - + disk_event_uevent(disk, DISK_EVENT_MEDIA_CHANGE); inc_diskseq(disk); - if (__invalidate_device(disk->part0, true)) - pr_warn("VFS: busy inodes on changed media %s\n", - disk->disk_name); + bdev_mark_dead(disk->part0, true); set_bit(GD_NEED_PART_SCAN, &disk->state); - return true; } EXPORT_SYMBOL_GPL(disk_force_media_change); diff --git a/block/genhd.c b/block/genhd.c index 3d287b32d50d..cc32a0c704eb 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -554,7 +554,7 @@ out_exit_elevator: } EXPORT_SYMBOL(device_add_disk); -static void blk_report_disk_dead(struct gendisk *disk) +static void blk_report_disk_dead(struct gendisk *disk, bool surprise) { struct block_device *bdev; unsigned long idx; @@ -565,10 +565,7 @@ static void blk_report_disk_dead(struct gendisk *disk) continue; rcu_read_unlock(); - mutex_lock(&bdev->bd_holder_lock); - if (bdev->bd_holder_ops && bdev->bd_holder_ops->mark_dead) - bdev->bd_holder_ops->mark_dead(bdev); - mutex_unlock(&bdev->bd_holder_lock); + bdev_mark_dead(bdev, surprise); put_device(&bdev->bd_device); rcu_read_lock(); @@ -576,14 +573,7 @@ static void blk_report_disk_dead(struct gendisk *disk) rcu_read_unlock(); } -/** - * blk_mark_disk_dead - mark a disk as dead - * @disk: disk to mark as dead - * - * Mark as disk as dead (e.g. surprise removed) and don't accept any new I/O - * to this disk. - */ -void blk_mark_disk_dead(struct gendisk *disk) +static void __blk_mark_disk_dead(struct gendisk *disk) { /* * Fail any new I/O. @@ -603,8 +593,19 @@ void blk_mark_disk_dead(struct gendisk *disk) * Prevent new I/O from crossing bio_queue_enter(). */ blk_queue_start_drain(disk->queue); +} - blk_report_disk_dead(disk); +/** + * blk_mark_disk_dead - mark a disk as dead + * @disk: disk to mark as dead + * + * Mark as disk as dead (e.g. surprise removed) and don't accept any new I/O + * to this disk. + */ +void blk_mark_disk_dead(struct gendisk *disk) +{ + __blk_mark_disk_dead(disk); + blk_report_disk_dead(disk, true); } EXPORT_SYMBOL_GPL(blk_mark_disk_dead); @@ -641,18 +642,20 @@ void del_gendisk(struct gendisk *disk) disk_del_events(disk); /* - * Prevent new openers by unlinked the bdev inode, and write out - * dirty data before marking the disk dead and stopping all I/O. + * Prevent new openers by unlinked the bdev inode. */ mutex_lock(&disk->open_mutex); - xa_for_each(&disk->part_tbl, idx, part) { + xa_for_each(&disk->part_tbl, idx, part) remove_inode_hash(part->bd_inode); - fsync_bdev(part); - __invalidate_device(part, true); - } mutex_unlock(&disk->open_mutex); - blk_mark_disk_dead(disk); + /* + * Tell the file system to write back all dirty data and shut down if + * it hasn't been notified earlier. + */ + if (!test_bit(GD_DEAD, &disk->state)) + blk_report_disk_dead(disk, false); + __blk_mark_disk_dead(disk); /* * Drop all partitions now that the disk is marked dead. diff --git a/block/ioctl.c b/block/ioctl.c index 3be11941fb2d..648670ddb164 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -364,7 +364,14 @@ static int blkdev_flushbuf(struct block_device *bdev, unsigned cmd, { if (!capable(CAP_SYS_ADMIN)) return -EACCES; - fsync_bdev(bdev); + + mutex_lock(&bdev->bd_holder_lock); + if (bdev->bd_holder_ops && bdev->bd_holder_ops->sync) + bdev->bd_holder_ops->sync(bdev); + else + sync_blockdev(bdev); + mutex_unlock(&bdev->bd_holder_lock); + invalidate_bdev(bdev); return 0; } diff --git a/block/partitions/core.c b/block/partitions/core.c index 13a7341299a9..e137a87f4db0 100644 --- a/block/partitions/core.c +++ b/block/partitions/core.c @@ -281,10 +281,7 @@ static void delete_partition(struct block_device *part) * looked up any more even when openers still hold references. */ remove_inode_hash(part->bd_inode); - - fsync_bdev(part); - __invalidate_device(part, true); - + bdev_mark_dead(part, false); drop_partition(part); } diff --git a/drivers/block/amiflop.c b/drivers/block/amiflop.c index e460c9799d9f..2b98114a9fe0 100644 --- a/drivers/block/amiflop.c +++ b/drivers/block/amiflop.c @@ -1547,7 +1547,6 @@ static int fd_locked_ioctl(struct block_device *bdev, blk_mode_t mode, rel_fdc(); return -EBUSY; } - fsync_bdev(bdev); if (fd_motor_on(drive) == 0) { rel_fdc(); return -ENODEV; diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 2db9b186b977..ea4eb88a2e45 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -3255,7 +3255,7 @@ static int set_geometry(unsigned int cmd, struct floppy_struct *g, if (!disk || ITYPE(drive_state[cnt].fd_device) != type) continue; - __invalidate_device(disk->part0, true); + disk_force_media_change(disk); } mutex_unlock(&open_lock); } else { diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 637c5bda2387..9f2d412fc560 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -603,7 +603,7 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, goto out_err; /* and ... switch */ - disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE); + disk_force_media_change(lo->lo_disk); blk_mq_freeze_queue(lo->lo_queue); mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask); lo->lo_backing_file = file; @@ -1067,7 +1067,7 @@ static int loop_configure(struct loop_device *lo, blk_mode_t mode, /* suppress uevents while reconfiguring the device */ dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 1); - disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE); + disk_force_media_change(lo->lo_disk); set_disk_ro(lo->lo_disk, (lo->lo_flags & LO_FLAGS_READ_ONLY) != 0); lo->use_dio = lo->lo_flags & LO_FLAGS_DIRECT_IO; @@ -1171,7 +1171,7 @@ static void __loop_clr_fd(struct loop_device *lo, bool release) if (!release) blk_mq_unfreeze_queue(lo->lo_queue); - disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE); + disk_force_media_change(lo->lo_disk); if (lo->lo_flags & LO_FLAGS_PARTSCAN) { int err; diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 8576d696c7a2..42e0159bb258 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1434,12 +1434,10 @@ static int nbd_start_device_ioctl(struct nbd_device *nbd) return ret; } -static void nbd_clear_sock_ioctl(struct nbd_device *nbd, - struct block_device *bdev) +static void nbd_clear_sock_ioctl(struct nbd_device *nbd) { + blk_mark_disk_dead(nbd->disk); nbd_clear_sock(nbd); - __invalidate_device(bdev, true); - nbd_bdev_reset(nbd); if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, &nbd->config->runtime_flags)) nbd_config_put(nbd); @@ -1465,7 +1463,7 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, case NBD_DISCONNECT: return nbd_disconnect(nbd); case NBD_CLEAR_SOCK: - nbd_clear_sock_ioctl(nbd, bdev); + nbd_clear_sock_ioctl(nbd); return 0; case NBD_SET_SOCK: return nbd_add_socket(nbd, arg, false); diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c index 50a5ff70814a..215597f73be4 100644 --- a/drivers/s390/block/dasd.c +++ b/drivers/s390/block/dasd.c @@ -3636,11 +3636,8 @@ int dasd_generic_set_offline(struct ccw_device *cdev) * so sync bdev first and then wait for our queues to become * empty */ - if (device->block) { - rc = fsync_bdev(device->block->bdev); - if (rc != 0) - goto interrupted; - } + if (device->block) + bdev_mark_dead(device->block->bdev, false); dasd_schedule_device_bh(device); rc = wait_event_interruptible(shutdown_waitq, _wait_for_empty_queues(device)); diff --git a/fs/buffer.c b/fs/buffer.c index 3aa2380a75e1..084a6ade108a 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1226,19 +1226,14 @@ EXPORT_SYMBOL(mark_buffer_dirty); void mark_buffer_write_io_error(struct buffer_head *bh) { - struct super_block *sb; - set_buffer_write_io_error(bh); /* FIXME: do we need to set this in both places? */ if (bh->b_folio && bh->b_folio->mapping) mapping_set_error(bh->b_folio->mapping, -EIO); - if (bh->b_assoc_map) + if (bh->b_assoc_map) { mapping_set_error(bh->b_assoc_map, -EIO); - rcu_read_lock(); - sb = READ_ONCE(bh->b_bdev->bd_super); - if (sb) - errseq_set(&sb->s_wb_err, -EIO); - rcu_read_unlock(); + errseq_set(&bh->b_assoc_map->host->i_sb->s_wb_err, -EIO); + } } EXPORT_SYMBOL(mark_buffer_write_io_error); diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c index e755b2223936..5ee7d7bbb361 100644 --- a/fs/cramfs/inode.c +++ b/fs/cramfs/inode.c @@ -486,12 +486,16 @@ static void cramfs_kill_sb(struct super_block *sb) { struct cramfs_sb_info *sbi = CRAMFS_SB(sb); + generic_shutdown_super(sb); + if (IS_ENABLED(CONFIG_CRAMFS_MTD) && sb->s_mtd) { if (sbi && sbi->mtd_point_size) mtd_unpoint(sb->s_mtd, 0, sbi->mtd_point_size); - kill_mtd_super(sb); + put_mtd_device(sb->s_mtd); + sb->s_mtd = NULL; } else if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV) && sb->s_bdev) { - kill_block_super(sb); + sync_blockdev(sb->s_bdev); + blkdev_put(sb->s_bdev, sb); } kfree(sbi); } diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h index 729ada9e26e8..f55498e5c23d 100644 --- a/fs/exfat/exfat_fs.h +++ b/fs/exfat/exfat_fs.h @@ -273,8 +273,6 @@ struct exfat_sb_info { spinlock_t inode_hash_lock; struct hlist_head inode_hashtable[EXFAT_HASH_SIZE]; - - struct rcu_head rcu; }; #define EXFAT_CACHE_VALID 0 diff --git a/fs/exfat/super.c b/fs/exfat/super.c index 8e0ca4b0fc8f..2778bd9b631e 100644 --- a/fs/exfat/super.c +++ b/fs/exfat/super.c @@ -31,16 +31,6 @@ static void exfat_free_iocharset(struct exfat_sb_info *sbi) kfree(sbi->options.iocharset); } -static void exfat_delayed_free(struct rcu_head *p) -{ - struct exfat_sb_info *sbi = container_of(p, struct exfat_sb_info, rcu); - - unload_nls(sbi->nls_io); - exfat_free_iocharset(sbi); - exfat_free_upcase_table(sbi); - kfree(sbi); -} - static void exfat_put_super(struct super_block *sb) { struct exfat_sb_info *sbi = EXFAT_SB(sb); @@ -50,7 +40,8 @@ static void exfat_put_super(struct super_block *sb) brelse(sbi->boot_bh); mutex_unlock(&sbi->s_lock); - call_rcu(&sbi->rcu, exfat_delayed_free); + unload_nls(sbi->nls_io); + exfat_free_upcase_table(sbi); } static int exfat_sync_fs(struct super_block *sb, int wait) @@ -709,9 +700,6 @@ free_table: check_nls_io: unload_nls(sbi->nls_io); - exfat_free_iocharset(sbi); - sb->s_fs_info = NULL; - kfree(sbi); return err; } @@ -720,14 +708,18 @@ static int exfat_get_tree(struct fs_context *fc) return get_tree_bdev(fc, exfat_fill_super); } +static void exfat_free_sbi(struct exfat_sb_info *sbi) +{ + exfat_free_iocharset(sbi); + kfree(sbi); +} + static void exfat_free(struct fs_context *fc) { struct exfat_sb_info *sbi = fc->s_fs_info; - if (sbi) { - exfat_free_iocharset(sbi); - kfree(sbi); - } + if (sbi) + exfat_free_sbi(sbi); } static int exfat_reconfigure(struct fs_context *fc) @@ -772,12 +764,21 @@ static int exfat_init_fs_context(struct fs_context *fc) return 0; } +static void exfat_kill_sb(struct super_block *sb) +{ + struct exfat_sb_info *sbi = sb->s_fs_info; + + kill_block_super(sb); + if (sbi) + exfat_free_sbi(sbi); +} + static struct file_system_type exfat_fs_type = { .owner = THIS_MODULE, .name = "exfat", .init_fs_context = exfat_init_fs_context, .parameters = exfat_parameters, - .kill_sb = kill_block_super, + .kill_sb = exfat_kill_sb, .fs_flags = FS_REQUIRES_DEV, }; diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c index 77f318ec8abb..b38d59581411 100644 --- a/fs/ext4/ext4_jbd2.c +++ b/fs/ext4/ext4_jbd2.c @@ -234,8 +234,7 @@ int __ext4_journal_get_write_access(const char *where, unsigned int line, might_sleep(); - if (bh->b_bdev->bd_super) - ext4_check_bdev_write_error(bh->b_bdev->bd_super); + ext4_check_bdev_write_error(sb); if (ext4_handle_valid(handle)) { err = jbd2_journal_get_write_access(handle, bh); diff --git a/fs/ext4/super.c b/fs/ext4/super.c index cb1ff47af156..73547d2334fd 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -93,6 +93,7 @@ static int ext4_get_tree(struct fs_context *fc); static int ext4_reconfigure(struct fs_context *fc); static void ext4_fc_free(struct fs_context *fc); static int ext4_init_fs_context(struct fs_context *fc); +static void ext4_kill_sb(struct super_block *sb); static const struct fs_parameter_spec ext4_param_specs[]; /* @@ -135,12 +136,12 @@ static struct file_system_type ext2_fs_type = { .name = "ext2", .init_fs_context = ext4_init_fs_context, .parameters = ext4_param_specs, - .kill_sb = kill_block_super, + .kill_sb = ext4_kill_sb, .fs_flags = FS_REQUIRES_DEV, }; MODULE_ALIAS_FS("ext2"); MODULE_ALIAS("ext2"); -#define IS_EXT2_SB(sb) ((sb)->s_bdev->bd_holder == &ext2_fs_type) +#define IS_EXT2_SB(sb) ((sb)->s_type == &ext2_fs_type) #else #define IS_EXT2_SB(sb) (0) #endif @@ -151,12 +152,12 @@ static struct file_system_type ext3_fs_type = { .name = "ext3", .init_fs_context = ext4_init_fs_context, .parameters = ext4_param_specs, - .kill_sb = kill_block_super, + .kill_sb = ext4_kill_sb, .fs_flags = FS_REQUIRES_DEV, }; MODULE_ALIAS_FS("ext3"); MODULE_ALIAS("ext3"); -#define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type) +#define IS_EXT3_SB(sb) ((sb)->s_type == &ext3_fs_type) static inline void __ext4_read_bh(struct buffer_head *bh, blk_opf_t op_flags, @@ -1096,15 +1097,6 @@ void ext4_update_dynamic_rev(struct super_block *sb) */ } -static void ext4_bdev_mark_dead(struct block_device *bdev) -{ - ext4_force_shutdown(bdev->bd_holder, EXT4_GOING_FLAGS_NOLOGFLUSH); -} - -static const struct blk_holder_ops ext4_holder_ops = { - .mark_dead = ext4_bdev_mark_dead, -}; - /* * Open the external journal device */ @@ -1113,7 +1105,7 @@ static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb) struct block_device *bdev; bdev = blkdev_get_by_dev(dev, BLK_OPEN_READ | BLK_OPEN_WRITE, sb, - &ext4_holder_ops); + &fs_holder_ops); if (IS_ERR(bdev)) goto fail; return bdev; @@ -1125,25 +1117,6 @@ fail: return NULL; } -/* - * Release the journal device - */ -static void ext4_blkdev_remove(struct ext4_sb_info *sbi) -{ - struct block_device *bdev; - bdev = sbi->s_journal_bdev; - if (bdev) { - /* - * Invalidate the journal device's buffers. We don't want them - * floating about in memory - the physical journal device may - * hotswapped, and it breaks the `ro-after' testing code. - */ - invalidate_bdev(bdev); - blkdev_put(bdev, sbi->s_sb); - sbi->s_journal_bdev = NULL; - } -} - static inline struct inode *orphan_list_entry(struct list_head *l) { return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode; @@ -1339,8 +1312,13 @@ static void ext4_put_super(struct super_block *sb) sync_blockdev(sb->s_bdev); invalidate_bdev(sb->s_bdev); if (sbi->s_journal_bdev) { + /* + * Invalidate the journal device's buffers. We don't want them + * floating about in memory - the physical journal device may + * hotswapped, and it breaks the `ro-after' testing code. + */ sync_blockdev(sbi->s_journal_bdev); - ext4_blkdev_remove(sbi); + invalidate_bdev(sbi->s_journal_bdev); } ext4_xattr_destroy_cache(sbi->s_ea_inode_cache); @@ -5572,7 +5550,6 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) spin_lock_init(&sbi->s_bdev_wb_lock); errseq_check_and_advance(&sb->s_bdev->bd_inode->i_mapping->wb_err, &sbi->s_bdev_wb_err); - sb->s_bdev->bd_super = sb; EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS; ext4_orphan_cleanup(sb, es); EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS; @@ -5664,9 +5641,11 @@ failed_mount: kfree(get_qf_name(sb, sbi, i)); #endif fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy); - /* ext4_blkdev_remove() calls kill_bdev(), release bh before it. */ brelse(sbi->s_sbh); - ext4_blkdev_remove(sbi); + if (sbi->s_journal_bdev) { + invalidate_bdev(sbi->s_journal_bdev); + blkdev_put(sbi->s_journal_bdev, sb); + } out_fail: invalidate_bdev(sb->s_bdev); sb->s_fs_info = NULL; @@ -5854,7 +5833,10 @@ static journal_t *ext4_get_dev_journal(struct super_block *sb, if (WARN_ON_ONCE(!ext4_has_feature_journal(sb))) return NULL; + /* see get_tree_bdev why this is needed and safe */ + up_write(&sb->s_umount); bdev = ext4_blkdev_get(j_dev, sb); + down_write(&sb->s_umount); if (bdev == NULL) return NULL; @@ -7273,12 +7255,23 @@ static inline int ext3_feature_set_ok(struct super_block *sb) return 1; } +static void ext4_kill_sb(struct super_block *sb) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct block_device *journal_bdev = sbi ? sbi->s_journal_bdev : NULL; + + kill_block_super(sb); + + if (journal_bdev) + blkdev_put(journal_bdev, sb); +} + static struct file_system_type ext4_fs_type = { .owner = THIS_MODULE, .name = "ext4", .init_fs_context = ext4_init_fs_context, .parameters = ext4_param_specs, - .kill_sb = kill_block_super, + .kill_sb = ext4_kill_sb, .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP | FS_MGTIME, }; MODULE_ALIAS_FS("ext4"); diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index 01effd3fcb6c..a1ca394bc327 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -2181,12 +2181,14 @@ out_drop_write: if (err) return err; - err = freeze_super(sbi->sb); + err = freeze_super(sbi->sb, FREEZE_HOLDER_USERSPACE); if (err) return err; if (f2fs_readonly(sbi->sb)) { - thaw_super(sbi->sb); + err = thaw_super(sbi->sb, FREEZE_HOLDER_USERSPACE); + if (err) + return err; return -EROFS; } @@ -2240,6 +2242,6 @@ recover_out: out_err: f2fs_up_write(&sbi->cp_global_sem); f2fs_up_write(&sbi->gc_lock); - thaw_super(sbi->sb); + thaw_super(sbi->sb, FREEZE_HOLDER_USERSPACE); return err; } diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 28aeffc0048c..aa1f9a3a8037 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -1561,7 +1561,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi) int i; for (i = 0; i < sbi->s_ndevs; i++) { - blkdev_put(FDEV(i).bdev, sbi->sb->s_type); + blkdev_put(FDEV(i).bdev, sbi->sb); #ifdef CONFIG_BLK_DEV_ZONED kvfree(FDEV(i).blkz_seq); #endif @@ -4198,7 +4198,7 @@ static int f2fs_scan_devices(struct f2fs_sb_info *sbi) /* Single zoned block device mount */ FDEV(0).bdev = blkdev_get_by_dev(sbi->sb->s_bdev->bd_dev, mode, - sbi->sb->s_type, NULL); + sbi->sb, NULL); } else { /* Multi-device mount */ memcpy(FDEV(i).path, RDEV(i).path, MAX_PATH_LEN); @@ -4217,8 +4217,7 @@ static int f2fs_scan_devices(struct f2fs_sb_info *sbi) sbi->log_blocks_per_seg) - 1; } FDEV(i).bdev = blkdev_get_by_path(FDEV(i).path, mode, - sbi->sb->s_type, - NULL); + sbi->sb, NULL); } if (IS_ERR(FDEV(i).bdev)) return PTR_ERR(FDEV(i).bdev); diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index aca4b4811394..969ce991b0b0 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -1953,9 +1953,9 @@ static long __writeback_inodes_wb(struct bdi_writeback *wb, struct inode *inode = wb_inode(wb->b_io.prev); struct super_block *sb = inode->i_sb; - if (!trylock_super(sb)) { + if (!super_trylock_shared(sb)) { /* - * trylock_super() may fail consistently due to + * super_trylock_shared() may fail consistently due to * s_umount being grabbed by someone else. Don't use * requeue_io() to avoid busy retrying the inode/sb. */ diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index ec0296b35dfe..2f701335e8ee 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -689,7 +689,7 @@ static int gfs2_freeze_locally(struct gfs2_sbd *sdp) struct super_block *sb = sdp->sd_vfs; int error; - error = freeze_super(sb); + error = freeze_super(sb, FREEZE_HOLDER_USERSPACE); if (error) return error; @@ -697,7 +697,9 @@ static int gfs2_freeze_locally(struct gfs2_sbd *sdp) gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_FREEZE | GFS2_LFC_FREEZE_GO_SYNC); if (gfs2_withdrawn(sdp)) { - thaw_super(sb); + error = thaw_super(sb, FREEZE_HOLDER_USERSPACE); + if (error) + return error; return -EIO; } } @@ -712,7 +714,7 @@ static int gfs2_do_thaw(struct gfs2_sbd *sdp) error = gfs2_freeze_lock_shared(sdp); if (error) goto fail; - error = thaw_super(sb); + error = thaw_super(sb, FREEZE_HOLDER_USERSPACE); if (!error) return 0; @@ -761,7 +763,7 @@ out: * */ -static int gfs2_freeze_super(struct super_block *sb) +static int gfs2_freeze_super(struct super_block *sb, enum freeze_holder who) { struct gfs2_sbd *sdp = sb->s_fs_info; int error; @@ -816,7 +818,7 @@ out: * */ -static int gfs2_thaw_super(struct super_block *sb) +static int gfs2_thaw_super(struct super_block *sb, enum freeze_holder who) { struct gfs2_sbd *sdp = sb->s_fs_info; int error; diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c index 2dfbe2f188dd..c60bc7f628e1 100644 --- a/fs/gfs2/sys.c +++ b/fs/gfs2/sys.c @@ -168,10 +168,10 @@ static ssize_t freeze_store(struct gfs2_sbd *sdp, const char *buf, size_t len) switch (n) { case 0: - error = thaw_super(sdp->sd_vfs); + error = thaw_super(sdp->sd_vfs, FREEZE_HOLDER_USERSPACE); break; case 1: - error = freeze_super(sdp->sd_vfs); + error = freeze_super(sdp->sd_vfs, FREEZE_HOLDER_USERSPACE); break; default: return -EINVAL; diff --git a/fs/inode.c b/fs/inode.c index 0ad4fb4b8fe9..35fd688168c5 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -751,16 +751,11 @@ EXPORT_SYMBOL_GPL(evict_inodes); /** * invalidate_inodes - attempt to free all inodes on a superblock * @sb: superblock to operate on - * @kill_dirty: flag to guide handling of dirty inodes * - * Attempts to free all inodes for a given superblock. If there were any - * busy inodes return a non-zero value, else zero. - * If @kill_dirty is set, discard dirty inodes too, otherwise treat - * them as busy. + * Attempts to free all inodes (including dirty inodes) for a given superblock. */ -int invalidate_inodes(struct super_block *sb, bool kill_dirty) +void invalidate_inodes(struct super_block *sb) { - int busy = 0; struct inode *inode, *next; LIST_HEAD(dispose); @@ -772,14 +767,8 @@ again: spin_unlock(&inode->i_lock); continue; } - if (inode->i_state & I_DIRTY_ALL && !kill_dirty) { - spin_unlock(&inode->i_lock); - busy = 1; - continue; - } if (atomic_read(&inode->i_count)) { spin_unlock(&inode->i_lock); - busy = 1; continue; } @@ -797,8 +786,6 @@ again: spin_unlock(&sb->s_inode_list_lock); dispose_list(&dispose); - - return busy; } /* diff --git a/fs/internal.h b/fs/internal.h index f7a3dc111026..74d3b161dd2c 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -115,7 +115,7 @@ static inline void put_file_access(struct file *file) * super.c */ extern int reconfigure_super(struct fs_context *); -extern bool trylock_super(struct super_block *sb); +extern bool super_trylock_shared(struct super_block *sb); struct super_block *user_get_super(dev_t, bool excl); void put_super(struct super_block *sb); extern bool mount_capable(struct fs_context *); @@ -201,7 +201,7 @@ void lock_two_inodes(struct inode *inode1, struct inode *inode2, * fs-writeback.c */ extern long get_nr_dirty_inodes(void); -extern int invalidate_inodes(struct super_block *, bool); +void invalidate_inodes(struct super_block *sb); /* * dcache.c diff --git a/fs/ioctl.c b/fs/ioctl.c index d413e0b8f6c2..f5fd99d6b0d4 100644 --- a/fs/ioctl.c +++ b/fs/ioctl.c @@ -397,8 +397,8 @@ static int ioctl_fsfreeze(struct file *filp) /* Freeze */ if (sb->s_op->freeze_super) - return sb->s_op->freeze_super(sb); - return freeze_super(sb); + return sb->s_op->freeze_super(sb, FREEZE_HOLDER_USERSPACE); + return freeze_super(sb, FREEZE_HOLDER_USERSPACE); } static int ioctl_fsthaw(struct file *filp) @@ -410,8 +410,8 @@ static int ioctl_fsthaw(struct file *filp) /* Thaw */ if (sb->s_op->thaw_super) - return sb->s_op->thaw_super(sb); - return thaw_super(sb); + return sb->s_op->thaw_super(sb, FREEZE_HOLDER_USERSPACE); + return thaw_super(sb, FREEZE_HOLDER_USERSPACE); } static int ioctl_file_dedupe_range(struct file *file, diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c index 0ef8c71bde8e..a5d1fa4e7552 100644 --- a/fs/nilfs2/super.c +++ b/fs/nilfs2/super.c @@ -35,6 +35,7 @@ #include <linux/writeback.h> #include <linux/seq_file.h> #include <linux/mount.h> +#include <linux/fs_context.h> #include "nilfs.h" #include "export.h" #include "mdt.h" @@ -1216,7 +1217,6 @@ static int nilfs_remount(struct super_block *sb, int *flags, char *data) } struct nilfs_super_data { - struct block_device *bdev; __u64 cno; int flags; }; @@ -1283,64 +1283,49 @@ static int nilfs_identify(char *data, struct nilfs_super_data *sd) static int nilfs_set_bdev_super(struct super_block *s, void *data) { - s->s_bdev = data; - s->s_dev = s->s_bdev->bd_dev; + s->s_dev = *(dev_t *)data; return 0; } static int nilfs_test_bdev_super(struct super_block *s, void *data) { - return (void *)s->s_bdev == data; + return !(s->s_iflags & SB_I_RETIRED) && s->s_dev == *(dev_t *)data; } static struct dentry * nilfs_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) { - struct nilfs_super_data sd; + struct nilfs_super_data sd = { .flags = flags }; struct super_block *s; - struct dentry *root_dentry; - int err, s_new = false; + dev_t dev; + int err; - sd.bdev = blkdev_get_by_path(dev_name, sb_open_mode(flags), fs_type, - NULL); - if (IS_ERR(sd.bdev)) - return ERR_CAST(sd.bdev); + if (nilfs_identify(data, &sd)) + return ERR_PTR(-EINVAL); - sd.cno = 0; - sd.flags = flags; - if (nilfs_identify((char *)data, &sd)) { - err = -EINVAL; - goto failed; - } + err = lookup_bdev(dev_name, &dev); + if (err) + return ERR_PTR(err); - /* - * once the super is inserted into the list by sget, s_umount - * will protect the lockfs code from trying to start a snapshot - * while we are mounting - */ - mutex_lock(&sd.bdev->bd_fsfreeze_mutex); - if (sd.bdev->bd_fsfreeze_count > 0) { - mutex_unlock(&sd.bdev->bd_fsfreeze_mutex); - err = -EBUSY; - goto failed; - } s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, flags, - sd.bdev); - mutex_unlock(&sd.bdev->bd_fsfreeze_mutex); - if (IS_ERR(s)) { - err = PTR_ERR(s); - goto failed; - } + &dev); + if (IS_ERR(s)) + return ERR_CAST(s); if (!s->s_root) { - s_new = true; - - /* New superblock instance created */ - snprintf(s->s_id, sizeof(s->s_id), "%pg", sd.bdev); - sb_set_blocksize(s, block_size(sd.bdev)); - - err = nilfs_fill_super(s, data, flags & SB_SILENT ? 1 : 0); + /* + * We drop s_umount here because we need to open the bdev and + * bdev->open_mutex ranks above s_umount (blkdev_put() -> + * __invalidate_device()). It is safe because we have active sb + * reference and SB_BORN is not set yet. + */ + up_write(&s->s_umount); + err = setup_bdev_super(s, flags, NULL); + down_write(&s->s_umount); + if (!err) + err = nilfs_fill_super(s, data, + flags & SB_SILENT ? 1 : 0); if (err) goto failed_super; @@ -1366,24 +1351,18 @@ nilfs_mount(struct file_system_type *fs_type, int flags, } if (sd.cno) { + struct dentry *root_dentry; + err = nilfs_attach_snapshot(s, sd.cno, &root_dentry); if (err) goto failed_super; - } else { - root_dentry = dget(s->s_root); + return root_dentry; } - if (!s_new) - blkdev_put(sd.bdev, fs_type); - - return root_dentry; + return dget(s->s_root); failed_super: deactivate_locked_super(s); - - failed: - if (!s_new) - blkdev_put(sd.bdev, fs_type); return ERR_PTR(err); } diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c index 1a02072b6b0e..5fffddea554f 100644 --- a/fs/ntfs3/super.c +++ b/fs/ntfs3/super.c @@ -569,9 +569,9 @@ static void init_once(void *foo) } /* - * put_ntfs - Noinline to reduce binary size. + * Noinline to reduce binary size. */ -static noinline void put_ntfs(struct ntfs_sb_info *sbi) +static noinline void ntfs3_free_sbi(struct ntfs_sb_info *sbi) { kfree(sbi->new_rec); kvfree(ntfs_put_shared(sbi->upcase)); @@ -625,12 +625,6 @@ static void ntfs_put_super(struct super_block *sb) /* Mark rw ntfs as clear, if possible. */ ntfs_set_state(sbi, NTFS_DIRTY_CLEAR); - - put_mount_options(sbi->options); - put_ntfs(sbi); - sb->s_fs_info = NULL; - - sync_blockdev(sb->s_bdev); } static int ntfs_statfs(struct dentry *dentry, struct kstatfs *buf) @@ -1564,15 +1558,7 @@ load_root: put_inode_out: iput(inode); out: - /* - * Free resources here. - * ntfs_fs_free will be called with fc->s_fs_info = NULL - */ - put_mount_options(sbi->options); - put_ntfs(sbi); - sb->s_fs_info = NULL; kfree(boot2); - return err; } @@ -1659,7 +1645,7 @@ static void ntfs_fs_free(struct fs_context *fc) struct ntfs_sb_info *sbi = fc->s_fs_info; if (sbi) - put_ntfs(sbi); + ntfs3_free_sbi(sbi); if (opts) put_mount_options(opts); @@ -1728,13 +1714,24 @@ free_opts: return -ENOMEM; } +static void ntfs3_kill_sb(struct super_block *sb) +{ + struct ntfs_sb_info *sbi = sb->s_fs_info; + + kill_block_super(sb); + + if (sbi->options) + put_mount_options(sbi->options); + ntfs3_free_sbi(sbi); +} + // clang-format off static struct file_system_type ntfs_fs_type = { .owner = THIS_MODULE, .name = "ntfs3", .init_fs_context = ntfs_init_fs_context, .parameters = ntfs_fs_parameters, - .kill_sb = kill_block_super, + .kill_sb = ntfs3_kill_sb, .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP, }; // clang-format on diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c index 25d8072ccfce..c19c730c26e2 100644 --- a/fs/ocfs2/journal.c +++ b/fs/ocfs2/journal.c @@ -557,7 +557,7 @@ static void ocfs2_abort_trigger(struct jbd2_buffer_trigger_type *triggers, (unsigned long)bh, (unsigned long long)bh->b_blocknr); - ocfs2_error(bh->b_bdev->bd_super, + ocfs2_error(bh->b_assoc_map->host->i_sb, "JBD2 has aborted our journal, ocfs2 cannot continue\n"); } @@ -780,14 +780,14 @@ void ocfs2_journal_dirty(handle_t *handle, struct buffer_head *bh) mlog_errno(status); if (!is_handle_aborted(handle)) { journal_t *journal = handle->h_transaction->t_journal; - struct super_block *sb = bh->b_bdev->bd_super; mlog(ML_ERROR, "jbd2_journal_dirty_metadata failed. " "Aborting transaction and journal.\n"); handle->h_err = status; jbd2_journal_abort_handle(handle); jbd2_journal_abort(journal, status); - ocfs2_abort(sb, "Journal already aborted.\n"); + ocfs2_abort(bh->b_assoc_map->host->i_sb, + "Journal already aborted.\n"); } } } diff --git a/fs/romfs/super.c b/fs/romfs/super.c index d89739655f9e..5c35f6c76037 100644 --- a/fs/romfs/super.c +++ b/fs/romfs/super.c @@ -582,16 +582,18 @@ static int romfs_init_fs_context(struct fs_context *fc) */ static void romfs_kill_sb(struct super_block *sb) { + generic_shutdown_super(sb); + #ifdef CONFIG_ROMFS_ON_MTD if (sb->s_mtd) { - kill_mtd_super(sb); - return; + put_mtd_device(sb->s_mtd); + sb->s_mtd = NULL; } #endif #ifdef CONFIG_ROMFS_ON_BLOCK if (sb->s_bdev) { - kill_block_super(sb); - return; + sync_blockdev(sb->s_bdev); + blkdev_put(sb->s_bdev, sb); } #endif } diff --git a/fs/super.c b/fs/super.c index e04a403dbffd..692654c2af36 100644 --- a/fs/super.c +++ b/fs/super.c @@ -39,7 +39,7 @@ #include <uapi/linux/mount.h> #include "internal.h" -static int thaw_super_locked(struct super_block *sb); +static int thaw_super_locked(struct super_block *sb, enum freeze_holder who); static LIST_HEAD(super_blocks); static DEFINE_SPINLOCK(sb_lock); @@ -50,6 +50,130 @@ static char *sb_writers_name[SB_FREEZE_LEVELS] = { "sb_internal", }; +static inline void __super_lock(struct super_block *sb, bool excl) +{ + if (excl) + down_write(&sb->s_umount); + else + down_read(&sb->s_umount); +} + +static inline void super_unlock(struct super_block *sb, bool excl) +{ + if (excl) + up_write(&sb->s_umount); + else + up_read(&sb->s_umount); +} + +static inline void __super_lock_excl(struct super_block *sb) +{ + __super_lock(sb, true); +} + +static inline void super_unlock_excl(struct super_block *sb) +{ + super_unlock(sb, true); +} + +static inline void super_unlock_shared(struct super_block *sb) +{ + super_unlock(sb, false); +} + +static inline bool wait_born(struct super_block *sb) +{ + unsigned int flags; + + /* + * Pairs with smp_store_release() in super_wake() and ensures + * that we see SB_BORN or SB_DYING after we're woken. + */ + flags = smp_load_acquire(&sb->s_flags); + return flags & (SB_BORN | SB_DYING); +} + +/** + * super_lock - wait for superblock to become ready and lock it + * @sb: superblock to wait for + * @excl: whether exclusive access is required + * + * If the superblock has neither passed through vfs_get_tree() or + * generic_shutdown_super() yet wait for it to happen. Either superblock + * creation will succeed and SB_BORN is set by vfs_get_tree() or we're + * woken and we'll see SB_DYING. + * + * The caller must have acquired a temporary reference on @sb->s_count. + * + * Return: This returns true if SB_BORN was set, false if SB_DYING was + * set. The function acquires s_umount and returns with it held. + */ +static __must_check bool super_lock(struct super_block *sb, bool excl) +{ + + lockdep_assert_not_held(&sb->s_umount); + +relock: + __super_lock(sb, excl); + + /* + * Has gone through generic_shutdown_super() in the meantime. + * @sb->s_root is NULL and @sb->s_active is 0. No one needs to + * grab a reference to this. Tell them so. + */ + if (sb->s_flags & SB_DYING) + return false; + + /* Has called ->get_tree() successfully. */ + if (sb->s_flags & SB_BORN) + return true; + + super_unlock(sb, excl); + + /* wait until the superblock is ready or dying */ + wait_var_event(&sb->s_flags, wait_born(sb)); + + /* + * Neither SB_BORN nor SB_DYING are ever unset so we never loop. + * Just reacquire @sb->s_umount for the caller. + */ + goto relock; +} + +/* wait and acquire read-side of @sb->s_umount */ +static inline bool super_lock_shared(struct super_block *sb) +{ + return super_lock(sb, false); +} + +/* wait and acquire write-side of @sb->s_umount */ +static inline bool super_lock_excl(struct super_block *sb) +{ + return super_lock(sb, true); +} + +/* wake waiters */ +#define SUPER_WAKE_FLAGS (SB_BORN | SB_DYING | SB_DEAD) +static void super_wake(struct super_block *sb, unsigned int flag) +{ + WARN_ON_ONCE((flag & ~SUPER_WAKE_FLAGS)); + WARN_ON_ONCE(hweight32(flag & SUPER_WAKE_FLAGS) > 1); + + /* + * Pairs with smp_load_acquire() in super_lock() to make sure + * all initializations in the superblock are seen by the user + * seeing SB_BORN sent. + */ + smp_store_release(&sb->s_flags, sb->s_flags | flag); + /* + * Pairs with the barrier in prepare_to_wait_event() to make sure + * ___wait_var_event() either sees SB_BORN set or + * waitqueue_active() check in wake_up_var() sees the waiter. + */ + smp_mb(); + wake_up_var(&sb->s_flags); +} + /* * One thing we have to be careful of with a per-sb shrinker is that we don't * drop the last active reference to the superblock from within the shrinker. @@ -76,7 +200,7 @@ static unsigned long super_cache_scan(struct shrinker *shrink, if (!(sc->gfp_mask & __GFP_FS)) return SHRINK_STOP; - if (!trylock_super(sb)) + if (!super_trylock_shared(sb)) return SHRINK_STOP; if (sb->s_op->nr_cached_objects) @@ -110,7 +234,7 @@ static unsigned long super_cache_scan(struct shrinker *shrink, freed += sb->s_op->free_cached_objects(sb, sc); } - up_read(&sb->s_umount); + super_unlock_shared(sb); return freed; } @@ -123,17 +247,17 @@ static unsigned long super_cache_count(struct shrinker *shrink, sb = container_of(shrink, struct super_block, s_shrink); /* - * We don't call trylock_super() here as it is a scalability bottleneck, - * so we're exposed to partial setup state. The shrinker rwsem does not - * protect filesystem operations backing list_lru_shrink_count() or - * s_op->nr_cached_objects(). Counts can change between - * super_cache_count and super_cache_scan, so we really don't need locks - * here. + * We don't call super_trylock_shared() here as it is a scalability + * bottleneck, so we're exposed to partial setup state. The shrinker + * rwsem does not protect filesystem operations backing + * list_lru_shrink_count() or s_op->nr_cached_objects(). Counts can + * change between super_cache_count and super_cache_scan, so we really + * don't need locks here. * * However, if we are currently mounting the superblock, the underlying * filesystem might be in a state of partial construction and hence it - * is dangerous to access it. trylock_super() uses a SB_BORN check to - * avoid this situation, so do the same here. The memory barrier is + * is dangerous to access it. super_trylock_shared() uses a SB_BORN check + * to avoid this situation, so do the same here. The memory barrier is * matched with the one in mount_fs() as we don't hold locks here. */ if (!(sb->s_flags & SB_BORN)) @@ -176,7 +300,7 @@ static void destroy_unused_super(struct super_block *s) { if (!s) return; - up_write(&s->s_umount); + super_unlock_excl(s); list_lru_destroy(&s->s_dentry_lru); list_lru_destroy(&s->s_inode_lru); security_sb_free(s); @@ -337,10 +461,29 @@ void deactivate_locked_super(struct super_block *s) list_lru_destroy(&s->s_dentry_lru); list_lru_destroy(&s->s_inode_lru); + /* + * Remove it from @fs_supers so it isn't found by new + * sget{_fc}() walkers anymore. Any concurrent mounter still + * managing to grab a temporary reference is guaranteed to + * already see SB_DYING and will wait until we notify them about + * SB_DEAD. + */ + spin_lock(&sb_lock); + hlist_del_init(&s->s_instances); + spin_unlock(&sb_lock); + + /* + * Let concurrent mounts know that this thing is really dead. + * We don't need @sb->s_umount here as every concurrent caller + * will see SB_DYING and either discard the superblock or wait + * for SB_DEAD. + */ + super_wake(s, SB_DEAD); + put_filesystem(fs); put_super(s); } else { - up_write(&s->s_umount); + super_unlock_excl(s); } } @@ -357,7 +500,7 @@ EXPORT_SYMBOL(deactivate_locked_super); void deactivate_super(struct super_block *s) { if (!atomic_add_unless(&s->s_active, -1, 1)) { - down_write(&s->s_umount); + __super_lock_excl(s); deactivate_locked_super(s); } } @@ -379,20 +522,61 @@ EXPORT_SYMBOL(deactivate_super); */ static int grab_super(struct super_block *s) __releases(sb_lock) { + bool born; + s->s_count++; spin_unlock(&sb_lock); - down_write(&s->s_umount); - if ((s->s_flags & SB_BORN) && atomic_inc_not_zero(&s->s_active)) { + born = super_lock_excl(s); + if (born && atomic_inc_not_zero(&s->s_active)) { put_super(s); return 1; } - up_write(&s->s_umount); + super_unlock_excl(s); put_super(s); return 0; } +static inline bool wait_dead(struct super_block *sb) +{ + unsigned int flags; + + /* + * Pairs with memory barrier in super_wake() and ensures + * that we see SB_DEAD after we're woken. + */ + flags = smp_load_acquire(&sb->s_flags); + return flags & SB_DEAD; +} + +/** + * grab_super_dead - acquire an active reference to a superblock + * @sb: superblock to acquire + * + * Acquire a temporary reference on a superblock and try to trade it for + * an active reference. This is used in sget{_fc}() to wait for a + * superblock to either become SB_BORN or for it to pass through + * sb->kill() and be marked as SB_DEAD. + * + * Return: This returns true if an active reference could be acquired, + * false if not. + */ +static bool grab_super_dead(struct super_block *sb) +{ + + sb->s_count++; + if (grab_super(sb)) { + put_super(sb); + lockdep_assert_held(&sb->s_umount); + return true; + } + wait_var_event(&sb->s_flags, wait_dead(sb)); + put_super(sb); + lockdep_assert_not_held(&sb->s_umount); + return false; +} + /* - * trylock_super - try to grab ->s_umount shared + * super_trylock_shared - try to grab ->s_umount shared * @sb: reference we are trying to grab * * Try to prevent fs shutdown. This is used in places where we @@ -408,13 +592,13 @@ static int grab_super(struct super_block *s) __releases(sb_lock) * of down_read(). There's a couple of places that are OK with that, but * it's very much not a general-purpose interface. */ -bool trylock_super(struct super_block *sb) +bool super_trylock_shared(struct super_block *sb) { if (down_read_trylock(&sb->s_umount)) { - if (!hlist_unhashed(&sb->s_instances) && - sb->s_root && (sb->s_flags & SB_BORN)) + if (!(sb->s_flags & SB_DYING) && sb->s_root && + (sb->s_flags & SB_BORN)) return true; - up_read(&sb->s_umount); + super_unlock_shared(sb); } return false; @@ -439,13 +623,13 @@ bool trylock_super(struct super_block *sb) void retire_super(struct super_block *sb) { WARN_ON(!sb->s_bdev); - down_write(&sb->s_umount); + __super_lock_excl(sb); if (sb->s_iflags & SB_I_PERSB_BDI) { bdi_unregister(sb->s_bdi); sb->s_iflags &= ~SB_I_PERSB_BDI; } sb->s_iflags |= SB_I_RETIRED; - up_write(&sb->s_umount); + super_unlock_excl(sb); } EXPORT_SYMBOL(retire_super); @@ -517,11 +701,17 @@ void generic_shutdown_super(struct super_block *sb) spin_unlock(&sb->s_inode_list_lock); } } - spin_lock(&sb_lock); - /* should be initialized for __put_super_and_need_restart() */ - hlist_del_init(&sb->s_instances); - spin_unlock(&sb_lock); - up_write(&sb->s_umount); + /* + * Broadcast to everyone that grabbed a temporary reference to this + * superblock before we removed it from @fs_supers that the superblock + * is dying. Every walker of @fs_supers outside of sget{_fc}() will now + * discard this superblock and treat it as dead. + * + * We leave the superblock on @fs_supers so it can be found by + * sget{_fc}() until we passed sb->kill_sb(). + */ + super_wake(sb, SB_DYING); + super_unlock_excl(sb); if (sb->s_bdi != &noop_backing_dev_info) { if (sb->s_iflags & SB_I_PERSB_BDI) bdi_unregister(sb->s_bdi); @@ -609,6 +799,11 @@ retry: s->s_type = fc->fs_type; s->s_iflags |= fc->s_iflags; strscpy(s->s_id, s->s_type->name, sizeof(s->s_id)); + /* + * Make the superblock visible on @super_blocks and @fs_supers. + * It's in a nascent state and users should wait on SB_BORN or + * SB_DYING to be set. + */ list_add_tail(&s->s_list, &super_blocks); hlist_add_head(&s->s_instances, &s->s_type->fs_supers); spin_unlock(&sb_lock); @@ -626,7 +821,7 @@ share_extant_sb: warnfc(fc, "reusing existing filesystem in another namespace not allowed"); return ERR_PTR(-EBUSY); } - if (!grab_super(old)) + if (!grab_super_dead(old)) goto retry; destroy_unused_super(s); return old; @@ -670,7 +865,7 @@ retry: destroy_unused_super(s); return ERR_PTR(-EBUSY); } - if (!grab_super(old)) + if (!grab_super_dead(old)) goto retry; destroy_unused_super(s); return old; @@ -703,7 +898,7 @@ EXPORT_SYMBOL(sget); void drop_super(struct super_block *sb) { - up_read(&sb->s_umount); + super_unlock_shared(sb); put_super(sb); } @@ -711,7 +906,7 @@ EXPORT_SYMBOL(drop_super); void drop_super_exclusive(struct super_block *sb) { - up_write(&sb->s_umount); + super_unlock_excl(sb); put_super(sb); } EXPORT_SYMBOL(drop_super_exclusive); @@ -722,7 +917,8 @@ static void __iterate_supers(void (*f)(struct super_block *)) spin_lock(&sb_lock); list_for_each_entry(sb, &super_blocks, s_list) { - if (hlist_unhashed(&sb->s_instances)) + /* Pairs with memory marrier in super_wake(). */ + if (smp_load_acquire(&sb->s_flags) & SB_DYING) continue; sb->s_count++; spin_unlock(&sb_lock); @@ -752,15 +948,15 @@ void iterate_supers(void (*f)(struct super_block *, void *), void *arg) spin_lock(&sb_lock); list_for_each_entry(sb, &super_blocks, s_list) { - if (hlist_unhashed(&sb->s_instances)) - continue; + bool born; + sb->s_count++; spin_unlock(&sb_lock); - down_read(&sb->s_umount); - if (sb->s_root && (sb->s_flags & SB_BORN)) + born = super_lock_shared(sb); + if (born && sb->s_root) f(sb, arg); - up_read(&sb->s_umount); + super_unlock_shared(sb); spin_lock(&sb_lock); if (p) @@ -788,13 +984,15 @@ void iterate_supers_type(struct file_system_type *type, spin_lock(&sb_lock); hlist_for_each_entry(sb, &type->fs_supers, s_instances) { + bool born; + sb->s_count++; spin_unlock(&sb_lock); - down_read(&sb->s_umount); - if (sb->s_root && (sb->s_flags & SB_BORN)) + born = super_lock_shared(sb); + if (born && sb->s_root) f(sb, arg); - up_read(&sb->s_umount); + super_unlock_shared(sb); spin_lock(&sb_lock); if (p) @@ -809,43 +1007,6 @@ void iterate_supers_type(struct file_system_type *type, EXPORT_SYMBOL(iterate_supers_type); /** - * get_super - get the superblock of a device - * @bdev: device to get the superblock for - * - * Scans the superblock list and finds the superblock of the file system - * mounted on the device given. %NULL is returned if no match is found. - */ -struct super_block *get_super(struct block_device *bdev) -{ - struct super_block *sb; - - if (!bdev) - return NULL; - - spin_lock(&sb_lock); -rescan: - list_for_each_entry(sb, &super_blocks, s_list) { - if (hlist_unhashed(&sb->s_instances)) - continue; - if (sb->s_bdev == bdev) { - sb->s_count++; - spin_unlock(&sb_lock); - down_read(&sb->s_umount); - /* still alive? */ - if (sb->s_root && (sb->s_flags & SB_BORN)) - return sb; - up_read(&sb->s_umount); - /* nope, got unmounted */ - spin_lock(&sb_lock); - __put_super(sb); - goto rescan; - } - } - spin_unlock(&sb_lock); - return NULL; -} - -/** * get_active_super - get an active reference to the superblock of a device * @bdev: device to get the superblock for * @@ -860,15 +1021,12 @@ struct super_block *get_active_super(struct block_device *bdev) if (!bdev) return NULL; -restart: spin_lock(&sb_lock); list_for_each_entry(sb, &super_blocks, s_list) { - if (hlist_unhashed(&sb->s_instances)) - continue; if (sb->s_bdev == bdev) { if (!grab_super(sb)) - goto restart; - up_write(&sb->s_umount); + return NULL; + super_unlock_excl(sb); return sb; } } @@ -881,28 +1039,21 @@ struct super_block *user_get_super(dev_t dev, bool excl) struct super_block *sb; spin_lock(&sb_lock); -rescan: list_for_each_entry(sb, &super_blocks, s_list) { - if (hlist_unhashed(&sb->s_instances)) - continue; if (sb->s_dev == dev) { + bool born; + sb->s_count++; spin_unlock(&sb_lock); - if (excl) - down_write(&sb->s_umount); - else - down_read(&sb->s_umount); /* still alive? */ - if (sb->s_root && (sb->s_flags & SB_BORN)) + born = super_lock(sb, excl); + if (born && sb->s_root) return sb; - if (excl) - up_write(&sb->s_umount); - else - up_read(&sb->s_umount); + super_unlock(sb, excl); /* nope, got unmounted */ spin_lock(&sb_lock); __put_super(sb); - goto rescan; + break; } } spin_unlock(&sb_lock); @@ -944,9 +1095,9 @@ int reconfigure_super(struct fs_context *fc) if (remount_ro) { if (!hlist_empty(&sb->s_pins)) { - up_write(&sb->s_umount); + super_unlock_excl(sb); group_pin_kill(&sb->s_pins); - down_write(&sb->s_umount); + __super_lock_excl(sb); if (!sb->s_root) return 0; if (sb->s_writers.frozen != SB_UNFROZEN) @@ -1009,9 +1160,9 @@ cancel_readonly: static void do_emergency_remount_callback(struct super_block *sb) { - down_write(&sb->s_umount); - if (sb->s_root && sb->s_bdev && (sb->s_flags & SB_BORN) && - !sb_rdonly(sb)) { + bool born = super_lock_excl(sb); + + if (born && sb->s_root && sb->s_bdev && !sb_rdonly(sb)) { struct fs_context *fc; fc = fs_context_for_reconfigure(sb->s_root, @@ -1022,7 +1173,7 @@ static void do_emergency_remount_callback(struct super_block *sb) put_fs_context(fc); } } - up_write(&sb->s_umount); + super_unlock_excl(sb); } static void do_emergency_remount(struct work_struct *work) @@ -1045,12 +1196,13 @@ void emergency_remount(void) static void do_thaw_all_callback(struct super_block *sb) { - down_write(&sb->s_umount); - if (sb->s_root && sb->s_flags & SB_BORN) { + bool born = super_lock_excl(sb); + + if (born && sb->s_root) { emergency_thaw_bdev(sb); - thaw_super_locked(sb); + thaw_super_locked(sb, FREEZE_HOLDER_USERSPACE); } else { - up_write(&sb->s_umount); + super_unlock_excl(sb); } } @@ -1209,31 +1361,66 @@ int get_tree_keyed(struct fs_context *fc, EXPORT_SYMBOL(get_tree_keyed); #ifdef CONFIG_BLOCK -static void fs_mark_dead(struct block_device *bdev) +/* + * Lock a super block that the callers holds a reference to. + * + * The caller needs to ensure that the super_block isn't being freed while + * calling this function, e.g. by holding a lock over the call to this function + * and the place that clears the pointer to the superblock used by this function + * before freeing the superblock. + */ +static bool super_lock_shared_active(struct super_block *sb) { - struct super_block *sb; + bool born = super_lock_shared(sb); - sb = get_super(bdev); - if (!sb) + if (!born || !sb->s_root || !(sb->s_flags & SB_ACTIVE)) { + super_unlock_shared(sb); + return false; + } + return true; +} + +static void fs_bdev_mark_dead(struct block_device *bdev, bool surprise) +{ + struct super_block *sb = bdev->bd_holder; + + /* bd_holder_lock ensures that the sb isn't freed */ + lockdep_assert_held(&bdev->bd_holder_lock); + + if (!super_lock_shared_active(sb)) return; + if (!surprise) + sync_filesystem(sb); + shrink_dcache_sb(sb); + invalidate_inodes(sb); if (sb->s_op->shutdown) sb->s_op->shutdown(sb); - drop_super(sb); + + super_unlock_shared(sb); } -static const struct blk_holder_ops fs_holder_ops = { - .mark_dead = fs_mark_dead, +static void fs_bdev_sync(struct block_device *bdev) +{ + struct super_block *sb = bdev->bd_holder; + + lockdep_assert_held(&bdev->bd_holder_lock); + + if (!super_lock_shared_active(sb)) + return; + sync_filesystem(sb); + super_unlock_shared(sb); +} + +const struct blk_holder_ops fs_holder_ops = { + .mark_dead = fs_bdev_mark_dead, + .sync = fs_bdev_sync, }; +EXPORT_SYMBOL_GPL(fs_holder_ops); static int set_bdev_super(struct super_block *s, void *data) { - s->s_bdev = data; - s->s_dev = s->s_bdev->bd_dev; - s->s_bdi = bdi_get(s->s_bdev->bd_disk->bdi); - - if (bdev_stable_writes(s->s_bdev)) - s->s_iflags |= SB_I_STABLE_WRITES; + s->s_dev = *(dev_t *)data; return 0; } @@ -1244,8 +1431,63 @@ static int set_bdev_super_fc(struct super_block *s, struct fs_context *fc) static int test_bdev_super_fc(struct super_block *s, struct fs_context *fc) { - return !(s->s_iflags & SB_I_RETIRED) && s->s_bdev == fc->sget_key; + return !(s->s_iflags & SB_I_RETIRED) && + s->s_dev == *(dev_t *)fc->sget_key; +} + +int setup_bdev_super(struct super_block *sb, int sb_flags, + struct fs_context *fc) +{ + blk_mode_t mode = sb_open_mode(sb_flags); + struct block_device *bdev; + + bdev = blkdev_get_by_dev(sb->s_dev, mode, sb, &fs_holder_ops); + if (IS_ERR(bdev)) { + if (fc) + errorf(fc, "%s: Can't open blockdev", fc->source); + return PTR_ERR(bdev); + } + + /* + * This really should be in blkdev_get_by_dev, but right now can't due + * to legacy issues that require us to allow opening a block device node + * writable from userspace even for a read-only block device. + */ + if ((mode & BLK_OPEN_WRITE) && bdev_read_only(bdev)) { + blkdev_put(bdev, sb); + return -EACCES; + } + + /* + * Until SB_BORN flag is set, there can be no active superblock + * references and thus no filesystem freezing. get_active_super() will + * just loop waiting for SB_BORN so even freeze_bdev() cannot proceed. + * + * It is enough to check bdev was not frozen before we set s_bdev. + */ + mutex_lock(&bdev->bd_fsfreeze_mutex); + if (bdev->bd_fsfreeze_count > 0) { + mutex_unlock(&bdev->bd_fsfreeze_mutex); + if (fc) + warnf(fc, "%pg: Can't mount, blockdev is frozen", bdev); + blkdev_put(bdev, sb); + return -EBUSY; + } + spin_lock(&sb_lock); + sb->s_bdev = bdev; + sb->s_bdi = bdi_get(bdev->bd_disk->bdi); + if (bdev_stable_writes(bdev)) + sb->s_iflags |= SB_I_STABLE_WRITES; + spin_unlock(&sb_lock); + mutex_unlock(&bdev->bd_fsfreeze_mutex); + + snprintf(sb->s_id, sizeof(sb->s_id), "%pg", bdev); + shrinker_debugfs_rename(&sb->s_shrink, "sb-%s:%s", sb->s_type->name, + sb->s_id); + sb_set_blocksize(sb, block_size(bdev)); + return 0; } +EXPORT_SYMBOL_GPL(setup_bdev_super); /** * get_tree_bdev - Get a superblock based on a single block device @@ -1256,73 +1498,49 @@ int get_tree_bdev(struct fs_context *fc, int (*fill_super)(struct super_block *, struct fs_context *)) { - struct block_device *bdev; struct super_block *s; int error = 0; + dev_t dev; if (!fc->source) return invalf(fc, "No source specified"); - bdev = blkdev_get_by_path(fc->source, sb_open_mode(fc->sb_flags), - fc->fs_type, &fs_holder_ops); - if (IS_ERR(bdev)) { - errorf(fc, "%s: Can't open blockdev", fc->source); - return PTR_ERR(bdev); - } - - /* Once the superblock is inserted into the list by sget_fc(), s_umount - * will protect the lockfs code from trying to start a snapshot while - * we are mounting - */ - mutex_lock(&bdev->bd_fsfreeze_mutex); - if (bdev->bd_fsfreeze_count > 0) { - mutex_unlock(&bdev->bd_fsfreeze_mutex); - warnf(fc, "%pg: Can't mount, blockdev is frozen", bdev); - blkdev_put(bdev, fc->fs_type); - return -EBUSY; + error = lookup_bdev(fc->source, &dev); + if (error) { + errorf(fc, "%s: Can't lookup blockdev", fc->source); + return error; } fc->sb_flags |= SB_NOSEC; - fc->sget_key = bdev; + fc->sget_key = &dev; s = sget_fc(fc, test_bdev_super_fc, set_bdev_super_fc); - mutex_unlock(&bdev->bd_fsfreeze_mutex); - if (IS_ERR(s)) { - blkdev_put(bdev, fc->fs_type); + if (IS_ERR(s)) return PTR_ERR(s); - } if (s->s_root) { /* Don't summarily change the RO/RW state. */ if ((fc->sb_flags ^ s->s_flags) & SB_RDONLY) { - warnf(fc, "%pg: Can't mount, would change RO state", bdev); + warnf(fc, "%pg: Can't mount, would change RO state", s->s_bdev); deactivate_locked_super(s); - blkdev_put(bdev, fc->fs_type); return -EBUSY; } - + } else { /* - * s_umount nests inside open_mutex during - * __invalidate_device(). blkdev_put() acquires - * open_mutex and can't be called under s_umount. Drop - * s_umount temporarily. This is safe as we're - * holding an active reference. + * We drop s_umount here because we need to open the bdev and + * bdev->open_mutex ranks above s_umount (blkdev_put() -> + * bdev_mark_dead()). It is safe because we have active sb + * reference and SB_BORN is not set yet. */ - up_write(&s->s_umount); - blkdev_put(bdev, fc->fs_type); - down_write(&s->s_umount); - } else { - snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev); - shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s", - fc->fs_type->name, s->s_id); - sb_set_blocksize(s, block_size(bdev)); - error = fill_super(s, fc); + super_unlock_excl(s); + error = setup_bdev_super(s, fc->sb_flags, fc); + __super_lock_excl(s); + if (!error) + error = fill_super(s, fc); if (error) { deactivate_locked_super(s); return error; } - s->s_flags |= SB_ACTIVE; - bdev->bd_super = s; } BUG_ON(fc->root); @@ -1333,79 +1551,52 @@ EXPORT_SYMBOL(get_tree_bdev); static int test_bdev_super(struct super_block *s, void *data) { - return !(s->s_iflags & SB_I_RETIRED) && (void *)s->s_bdev == data; + return !(s->s_iflags & SB_I_RETIRED) && s->s_dev == *(dev_t *)data; } struct dentry *mount_bdev(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, int (*fill_super)(struct super_block *, void *, int)) { - struct block_device *bdev; struct super_block *s; - int error = 0; + int error; + dev_t dev; - bdev = blkdev_get_by_path(dev_name, sb_open_mode(flags), fs_type, - &fs_holder_ops); - if (IS_ERR(bdev)) - return ERR_CAST(bdev); + error = lookup_bdev(dev_name, &dev); + if (error) + return ERR_PTR(error); - /* - * once the super is inserted into the list by sget, s_umount - * will protect the lockfs code from trying to start a snapshot - * while we are mounting - */ - mutex_lock(&bdev->bd_fsfreeze_mutex); - if (bdev->bd_fsfreeze_count > 0) { - mutex_unlock(&bdev->bd_fsfreeze_mutex); - error = -EBUSY; - goto error_bdev; - } - s = sget(fs_type, test_bdev_super, set_bdev_super, flags | SB_NOSEC, - bdev); - mutex_unlock(&bdev->bd_fsfreeze_mutex); + flags |= SB_NOSEC; + s = sget(fs_type, test_bdev_super, set_bdev_super, flags, &dev); if (IS_ERR(s)) - goto error_s; + return ERR_CAST(s); if (s->s_root) { if ((flags ^ s->s_flags) & SB_RDONLY) { deactivate_locked_super(s); - error = -EBUSY; - goto error_bdev; + return ERR_PTR(-EBUSY); } - + } else { /* - * s_umount nests inside open_mutex during - * __invalidate_device(). blkdev_put() acquires - * open_mutex and can't be called under s_umount. Drop - * s_umount temporarily. This is safe as we're - * holding an active reference. + * We drop s_umount here because we need to open the bdev and + * bdev->open_mutex ranks above s_umount (blkdev_put() -> + * bdev_mark_dead()). It is safe because we have active sb + * reference and SB_BORN is not set yet. */ - up_write(&s->s_umount); - blkdev_put(bdev, fs_type); - down_write(&s->s_umount); - } else { - snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev); - shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s", - fs_type->name, s->s_id); - sb_set_blocksize(s, block_size(bdev)); - error = fill_super(s, data, flags & SB_SILENT ? 1 : 0); + super_unlock_excl(s); + error = setup_bdev_super(s, flags, NULL); + __super_lock_excl(s); + if (!error) + error = fill_super(s, data, flags & SB_SILENT ? 1 : 0); if (error) { deactivate_locked_super(s); - goto error; + return ERR_PTR(error); } s->s_flags |= SB_ACTIVE; - bdev->bd_super = s; } return dget(s->s_root); - -error_s: - error = PTR_ERR(s); -error_bdev: - blkdev_put(bdev, fs_type); -error: - return ERR_PTR(error); } EXPORT_SYMBOL(mount_bdev); @@ -1413,10 +1604,11 @@ void kill_block_super(struct super_block *sb) { struct block_device *bdev = sb->s_bdev; - bdev->bd_super = NULL; generic_shutdown_super(sb); - sync_blockdev(bdev); - blkdev_put(bdev, sb->s_type); + if (bdev) { + sync_blockdev(bdev); + blkdev_put(bdev, sb); + } } EXPORT_SYMBOL(kill_block_super); @@ -1533,13 +1725,13 @@ int vfs_get_tree(struct fs_context *fc) WARN_ON(!sb->s_bdi); /* - * Write barrier is for super_cache_count(). We place it before setting - * SB_BORN as the data dependency between the two functions is the - * superblock structure contents that we just set up, not the SB_BORN - * flag. + * super_wake() contains a memory barrier which also care of + * ordering for super_cache_count(). We place it before setting + * SB_BORN as the data dependency between the two functions is + * the superblock structure contents that we just set up, not + * the SB_BORN flag. */ - smp_wmb(); - sb->s_flags |= SB_BORN; + super_wake(sb, SB_BORN); error = security_sb_set_mnt_opts(sb, fc->security, 0, NULL); if (unlikely(error)) { @@ -1644,14 +1836,43 @@ static void sb_freeze_unlock(struct super_block *sb, int level) percpu_up_write(sb->s_writers.rw_sem + level); } +static int wait_for_partially_frozen(struct super_block *sb) +{ + int ret = 0; + + do { + unsigned short old = sb->s_writers.frozen; + + up_write(&sb->s_umount); + ret = wait_var_event_killable(&sb->s_writers.frozen, + sb->s_writers.frozen != old); + down_write(&sb->s_umount); + } while (ret == 0 && + sb->s_writers.frozen != SB_UNFROZEN && + sb->s_writers.frozen != SB_FREEZE_COMPLETE); + + return ret; +} + /** * freeze_super - lock the filesystem and force it into a consistent state * @sb: the super to lock + * @who: context that wants to freeze * * Syncs the super to make sure the filesystem is consistent and calls the fs's - * freeze_fs. Subsequent calls to this without first thawing the fs will return + * freeze_fs. Subsequent calls to this without first thawing the fs may return * -EBUSY. * + * @who should be: + * * %FREEZE_HOLDER_USERSPACE if userspace wants to freeze the fs; + * * %FREEZE_HOLDER_KERNEL if the kernel wants to freeze the fs. + * + * The @who argument distinguishes between the kernel and userspace trying to + * freeze the filesystem. Although there cannot be multiple kernel freezes or + * multiple userspace freezes in effect at any given time, the kernel and + * userspace can both hold a filesystem frozen. The filesystem remains frozen + * until there are no kernel or userspace freezes in effect. + * * During this function, sb->s_writers.frozen goes through these values: * * SB_UNFROZEN: File system is normal, all writes progress as usual. @@ -1677,34 +1898,62 @@ static void sb_freeze_unlock(struct super_block *sb, int level) * * sb->s_writers.frozen is protected by sb->s_umount. */ -int freeze_super(struct super_block *sb) +int freeze_super(struct super_block *sb, enum freeze_holder who) { int ret; atomic_inc(&sb->s_active); - down_write(&sb->s_umount); + if (!super_lock_excl(sb)) + WARN(1, "Dying superblock while freezing!"); + +retry: + if (sb->s_writers.frozen == SB_FREEZE_COMPLETE) { + if (sb->s_writers.freeze_holders & who) { + deactivate_locked_super(sb); + return -EBUSY; + } + + WARN_ON(sb->s_writers.freeze_holders == 0); + + /* + * Someone else already holds this type of freeze; share the + * freeze and assign the active ref to the freeze. + */ + sb->s_writers.freeze_holders |= who; + super_unlock_excl(sb); + return 0; + } + if (sb->s_writers.frozen != SB_UNFROZEN) { - deactivate_locked_super(sb); - return -EBUSY; + ret = wait_for_partially_frozen(sb); + if (ret) { + deactivate_locked_super(sb); + return ret; + } + + goto retry; } if (!(sb->s_flags & SB_BORN)) { - up_write(&sb->s_umount); + super_unlock_excl(sb); return 0; /* sic - it's "nothing to do" */ } if (sb_rdonly(sb)) { /* Nothing to do really... */ + sb->s_writers.freeze_holders |= who; sb->s_writers.frozen = SB_FREEZE_COMPLETE; - up_write(&sb->s_umount); + wake_up_var(&sb->s_writers.frozen); + super_unlock_excl(sb); return 0; } sb->s_writers.frozen = SB_FREEZE_WRITE; /* Release s_umount to preserve sb_start_write -> s_umount ordering */ - up_write(&sb->s_umount); + super_unlock_excl(sb); sb_wait_write(sb, SB_FREEZE_WRITE); - down_write(&sb->s_umount); + if (!super_lock_excl(sb)) + WARN(1, "Dying superblock while freezing!"); /* Now we go and block page faults... */ sb->s_writers.frozen = SB_FREEZE_PAGEFAULT; @@ -1715,6 +1964,7 @@ int freeze_super(struct super_block *sb) if (ret) { sb->s_writers.frozen = SB_UNFROZEN; sb_freeze_unlock(sb, SB_FREEZE_PAGEFAULT); + wake_up_var(&sb->s_writers.frozen); deactivate_locked_super(sb); return ret; } @@ -1730,6 +1980,7 @@ int freeze_super(struct super_block *sb) "VFS:Filesystem freeze failed\n"); sb->s_writers.frozen = SB_UNFROZEN; sb_freeze_unlock(sb, SB_FREEZE_FS); + wake_up_var(&sb->s_writers.frozen); deactivate_locked_super(sb); return ret; } @@ -1738,24 +1989,50 @@ int freeze_super(struct super_block *sb) * For debugging purposes so that fs can warn if it sees write activity * when frozen is set to SB_FREEZE_COMPLETE, and for thaw_super(). */ + sb->s_writers.freeze_holders |= who; sb->s_writers.frozen = SB_FREEZE_COMPLETE; + wake_up_var(&sb->s_writers.frozen); lockdep_sb_freeze_release(sb); - up_write(&sb->s_umount); + super_unlock_excl(sb); return 0; } EXPORT_SYMBOL(freeze_super); -static int thaw_super_locked(struct super_block *sb) +/* + * Undoes the effect of a freeze_super_locked call. If the filesystem is + * frozen both by userspace and the kernel, a thaw call from either source + * removes that state without releasing the other state or unlocking the + * filesystem. + */ +static int thaw_super_locked(struct super_block *sb, enum freeze_holder who) { int error; - if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) { - up_write(&sb->s_umount); + if (sb->s_writers.frozen == SB_FREEZE_COMPLETE) { + if (!(sb->s_writers.freeze_holders & who)) { + super_unlock_excl(sb); + return -EINVAL; + } + + /* + * Freeze is shared with someone else. Release our hold and + * drop the active ref that freeze_super assigned to the + * freezer. + */ + if (sb->s_writers.freeze_holders & ~who) { + sb->s_writers.freeze_holders &= ~who; + deactivate_locked_super(sb); + return 0; + } + } else { + super_unlock_excl(sb); return -EINVAL; } if (sb_rdonly(sb)) { + sb->s_writers.freeze_holders &= ~who; sb->s_writers.frozen = SB_UNFROZEN; + wake_up_var(&sb->s_writers.frozen); goto out; } @@ -1764,15 +2041,16 @@ static int thaw_super_locked(struct super_block *sb) if (sb->s_op->unfreeze_fs) { error = sb->s_op->unfreeze_fs(sb); if (error) { - printk(KERN_ERR - "VFS:Filesystem thaw failed\n"); + printk(KERN_ERR "VFS:Filesystem thaw failed\n"); lockdep_sb_freeze_release(sb); - up_write(&sb->s_umount); + super_unlock_excl(sb); return error; } } + sb->s_writers.freeze_holders &= ~who; sb->s_writers.frozen = SB_UNFROZEN; + wake_up_var(&sb->s_writers.frozen); sb_freeze_unlock(sb, SB_FREEZE_FS); out: deactivate_locked_super(sb); @@ -1782,13 +2060,20 @@ out: /** * thaw_super -- unlock filesystem * @sb: the super to thaw + * @who: context that wants to freeze + * + * Unlocks the filesystem and marks it writeable again after freeze_super() + * if there are no remaining freezes on the filesystem. * - * Unlocks the filesystem and marks it writeable again after freeze_super(). + * @who should be: + * * %FREEZE_HOLDER_USERSPACE if userspace wants to thaw the fs; + * * %FREEZE_HOLDER_KERNEL if the kernel wants to thaw the fs. */ -int thaw_super(struct super_block *sb) +int thaw_super(struct super_block *sb, enum freeze_holder who) { - down_write(&sb->s_umount); - return thaw_super_locked(sb); + if (!super_lock_excl(sb)) + WARN(1, "Dying superblock while thawing!"); + return thaw_super_locked(sb, who); } EXPORT_SYMBOL(thaw_super); diff --git a/fs/xfs/scrub/fscounters.c b/fs/xfs/scrub/fscounters.c index e382a35e98d8..05be757668bb 100644 --- a/fs/xfs/scrub/fscounters.c +++ b/fs/xfs/scrub/fscounters.c @@ -1,4 +1,4 @@ -// SPDX-License-Identifier: GPL-2.0+ +// SPDX-License-Identifier: GPL-2.0-or-later /* * Copyright (C) 2019-2023 Oracle. All Rights Reserved. * Author: Darrick J. Wong <djwong@kernel.org> @@ -8,6 +8,8 @@ #include "xfs_shared.h" #include "xfs_format.h" #include "xfs_trans_resv.h" +#include "xfs_log_format.h" +#include "xfs_trans.h" #include "xfs_mount.h" #include "xfs_alloc.h" #include "xfs_ialloc.h" @@ -16,6 +18,7 @@ #include "xfs_ag.h" #include "xfs_rtalloc.h" #include "xfs_inode.h" +#include "xfs_icache.h" #include "scrub/scrub.h" #include "scrub/common.h" #include "scrub/trace.h" @@ -53,6 +56,7 @@ struct xchk_fscounters { uint64_t frextents; unsigned long long icount_min; unsigned long long icount_max; + bool frozen; }; /* @@ -123,6 +127,82 @@ xchk_fscount_warmup( return error; } +static inline int +xchk_fsfreeze( + struct xfs_scrub *sc) +{ + int error; + + error = freeze_super(sc->mp->m_super, FREEZE_HOLDER_KERNEL); + trace_xchk_fsfreeze(sc, error); + return error; +} + +static inline int +xchk_fsthaw( + struct xfs_scrub *sc) +{ + int error; + + /* This should always succeed, we have a kernel freeze */ + error = thaw_super(sc->mp->m_super, FREEZE_HOLDER_KERNEL); + trace_xchk_fsthaw(sc, error); + return error; +} + +/* + * We couldn't stabilize the filesystem long enough to sample all the variables + * that comprise the summary counters and compare them to the percpu counters. + * We need to disable all writer threads, which means taking the first two + * freeze levels to put userspace to sleep, and the third freeze level to + * prevent background threads from starting new transactions. Take one level + * more to prevent other callers from unfreezing the filesystem while we run. + */ +STATIC int +xchk_fscounters_freeze( + struct xfs_scrub *sc) +{ + struct xchk_fscounters *fsc = sc->buf; + int error = 0; + + if (sc->flags & XCHK_HAVE_FREEZE_PROT) { + sc->flags &= ~XCHK_HAVE_FREEZE_PROT; + mnt_drop_write_file(sc->file); + } + + /* Try to grab a kernel freeze. */ + while ((error = xchk_fsfreeze(sc)) == -EBUSY) { + if (xchk_should_terminate(sc, &error)) + return error; + + delay(HZ / 10); + } + if (error) + return error; + + fsc->frozen = true; + return 0; +} + +/* Thaw the filesystem after checking or repairing fscounters. */ +STATIC void +xchk_fscounters_cleanup( + void *buf) +{ + struct xchk_fscounters *fsc = buf; + struct xfs_scrub *sc = fsc->sc; + int error; + + if (!fsc->frozen) + return; + + error = xchk_fsthaw(sc); + if (error) + xfs_emerg(sc->mp, "still frozen after scrub, err=%d", error); + else + fsc->frozen = false; +} + int xchk_setup_fscounters( struct xfs_scrub *sc) @@ -140,6 +220,7 @@ xchk_setup_fscounters( sc->buf = kzalloc(sizeof(struct xchk_fscounters), XCHK_GFP_FLAGS); if (!sc->buf) return -ENOMEM; + sc->buf_cleanup = xchk_fscounters_cleanup; fsc = sc->buf; fsc->sc = sc; @@ -150,7 +231,18 @@ xchk_setup_fscounters( if (error) return error; - return xchk_trans_alloc(sc, 0); + /* + * Pause all writer activity in the filesystem while we're scrubbing to + * reduce the likelihood of background perturbations to the counters + * throwing off our calculations. + */ + if (sc->flags & XCHK_TRY_HARDER) { + error = xchk_fscounters_freeze(sc); + if (error) + return error; + } + + return xfs_trans_alloc_empty(sc->mp, &sc->tp); } /* @@ -290,8 +382,7 @@ retry: if (fsc->ifree > fsc->icount) { if (tries--) goto retry; - xchk_set_incomplete(sc); - return 0; + return -EDEADLOCK; } return 0; @@ -367,6 +458,8 @@ xchk_fscount_count_frextents( * Otherwise, we /might/ have a problem. If the change in the summations is * more than we want to tolerate, the filesystem is probably busy and we should * just send back INCOMPLETE and see if userspace will try again. + * + * If we're repairing then we require an exact match. */ static inline bool xchk_fscount_within_range( @@ -396,21 +489,7 @@ xchk_fscount_within_range( if (expected >= min_value && expected <= max_value) return true; - /* - * If the difference between the two summations is too large, the fs - * might just be busy and so we'll mark the scrub incomplete. Return - * true here so that we don't mark the counter corrupt. - * - * XXX: In the future when userspace can grant scrub permission to - * quiesce the filesystem to solve the outsized variance problem, this - * check should be moved up and the return code changed to signal to - * userspace that we need quiesce permission. - */ - if (max_value - min_value >= XCHK_FSCOUNT_MIN_VARIANCE) { - xchk_set_incomplete(sc); - return true; - } - + /* Everything else is bad. */ return false; } @@ -422,6 +501,7 @@ xchk_fscounters( struct xfs_mount *mp = sc->mp; struct xchk_fscounters *fsc = sc->buf; int64_t icount, ifree, fdblocks, frextents; + bool try_again = false; int error; /* Snapshot the percpu counters. */ @@ -431,9 +511,26 @@ xchk_fscounters( frextents = percpu_counter_sum(&mp->m_frextents); /* No negative values, please! */ - if (icount < 0 || ifree < 0 || fdblocks < 0 || frextents < 0) + if (icount < 0 || ifree < 0) xchk_set_corrupt(sc); + /* + * If the filesystem is not frozen, the counter summation calls above + * can race with xfs_mod_freecounter, which subtracts a requested space + * reservation from the counter and undoes the subtraction if that made + * the counter go negative. Therefore, it's possible to see negative + * values here, and we should only flag that as a corruption if we + * froze the fs. This is much more likely to happen with frextents + * since there are no reserved pools. + */ + if (fdblocks < 0 || frextents < 0) { + if (!fsc->frozen) + return -EDEADLOCK; + + xchk_set_corrupt(sc); + return 0; + } + /* See if icount is obviously wrong. */ if (icount < fsc->icount_min || icount > fsc->icount_max) xchk_set_corrupt(sc); @@ -447,12 +544,6 @@ xchk_fscounters( xchk_set_corrupt(sc); /* - * XXX: We can't quiesce percpu counter updates, so exit early. - * This can be re-enabled when we gain exclusive freeze functionality. - */ - return 0; - - /* * If ifree exceeds icount by more than the minimum variance then * something's probably wrong with the counters. */ @@ -463,8 +554,6 @@ xchk_fscounters( error = xchk_fscount_aggregate_agcounts(sc, fsc); if (!xchk_process_error(sc, 0, XFS_SB_BLOCK(mp), &error)) return error; - if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_INCOMPLETE) - return 0; /* Count the free extents counter for rt volumes. */ error = xchk_fscount_count_frextents(sc, fsc); @@ -473,20 +562,45 @@ xchk_fscounters( if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_INCOMPLETE) return 0; - /* Compare the in-core counters with whatever we counted. */ - if (!xchk_fscount_within_range(sc, icount, &mp->m_icount, fsc->icount)) - xchk_set_corrupt(sc); + /* + * Compare the in-core counters with whatever we counted. If the fs is + * frozen, we treat the discrepancy as a corruption because the freeze + * should have stabilized the counter values. Otherwise, we need + * userspace to call us back having granted us freeze permission. + */ + if (!xchk_fscount_within_range(sc, icount, &mp->m_icount, + fsc->icount)) { + if (fsc->frozen) + xchk_set_corrupt(sc); + else + try_again = true; + } - if (!xchk_fscount_within_range(sc, ifree, &mp->m_ifree, fsc->ifree)) - xchk_set_corrupt(sc); + if (!xchk_fscount_within_range(sc, ifree, &mp->m_ifree, fsc->ifree)) { + if (fsc->frozen) + xchk_set_corrupt(sc); + else + try_again = true; + } if (!xchk_fscount_within_range(sc, fdblocks, &mp->m_fdblocks, - fsc->fdblocks)) - xchk_set_corrupt(sc); + fsc->fdblocks)) { + if (fsc->frozen) + xchk_set_corrupt(sc); + else + try_again = true; + } if (!xchk_fscount_within_range(sc, frextents, &mp->m_frextents, - fsc->frextents)) - xchk_set_corrupt(sc); + fsc->frextents)) { + if (fsc->frozen) + xchk_set_corrupt(sc); + else + try_again = true; + } + + if (try_again) + return -EDEADLOCK; return 0; } diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c index 3d98f604765e..a0fffbcd022b 100644 --- a/fs/xfs/scrub/scrub.c +++ b/fs/xfs/scrub/scrub.c @@ -184,8 +184,10 @@ xchk_teardown( xchk_irele(sc, sc->ip); sc->ip = NULL; } - if (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) + if (sc->flags & XCHK_HAVE_FREEZE_PROT) { + sc->flags &= ~XCHK_HAVE_FREEZE_PROT; mnt_drop_write_file(sc->file); + } if (sc->buf) { if (sc->buf_cleanup) sc->buf_cleanup(sc->buf); @@ -505,6 +507,8 @@ retry_op: error = mnt_want_write_file(sc->file); if (error) goto out_sc; + + sc->flags |= XCHK_HAVE_FREEZE_PROT; } /* Set up for the operation. */ diff --git a/fs/xfs/scrub/scrub.h b/fs/xfs/scrub/scrub.h index e113f2f5c254..f8ba00e51ca9 100644 --- a/fs/xfs/scrub/scrub.h +++ b/fs/xfs/scrub/scrub.h @@ -106,6 +106,7 @@ struct xfs_scrub { /* XCHK state flags grow up from zero, XREP state flags grown down from 2^31 */ #define XCHK_TRY_HARDER (1U << 0) /* can't get resources, try again */ +#define XCHK_HAVE_FREEZE_PROT (1U << 1) /* do we have freeze protection? */ #define XCHK_FSGATES_DRAIN (1U << 2) /* defer ops draining enabled */ #define XCHK_NEED_DRAIN (1U << 3) /* scrub needs to drain defer ops */ #define XREP_ALREADY_FIXED (1U << 31) /* checking our repair work */ diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h index b3894daeb86a..0b54f1a1cf0c 100644 --- a/fs/xfs/scrub/trace.h +++ b/fs/xfs/scrub/trace.h @@ -98,6 +98,7 @@ TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_FSCOUNTERS); #define XFS_SCRUB_STATE_STRINGS \ { XCHK_TRY_HARDER, "try_harder" }, \ + { XCHK_HAVE_FREEZE_PROT, "nofreeze" }, \ { XCHK_FSGATES_DRAIN, "fsgates_drain" }, \ { XCHK_NEED_DRAIN, "need_drain" }, \ { XREP_ALREADY_FIXED, "already_fixed" } @@ -693,6 +694,31 @@ TRACE_EVENT(xchk_fscounters_within_range, __entry->old_value) ) +DECLARE_EVENT_CLASS(xchk_fsfreeze_class, + TP_PROTO(struct xfs_scrub *sc, int error), + TP_ARGS(sc, error), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(unsigned int, type) + __field(int, error) + ), + TP_fast_assign( + __entry->dev = sc->mp->m_super->s_dev; + __entry->type = sc->sm->sm_type; + __entry->error = error; + ), + TP_printk("dev %d:%d type %s error %d", + MAJOR(__entry->dev), MINOR(__entry->dev), + __print_symbolic(__entry->type, XFS_SCRUB_TYPE_STRINGS), + __entry->error) +); +#define DEFINE_XCHK_FSFREEZE_EVENT(name) \ +DEFINE_EVENT(xchk_fsfreeze_class, name, \ + TP_PROTO(struct xfs_scrub *sc, int error), \ + TP_ARGS(sc, error)) +DEFINE_XCHK_FSFREEZE_EVENT(xchk_fsfreeze); +DEFINE_XCHK_FSFREEZE_EVENT(xchk_fsthaw); + TRACE_EVENT(xchk_refcount_incorrect, TP_PROTO(struct xfs_perag *pag, const struct xfs_refcount_irec *irec, xfs_nlink_t seen), diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index 15d1e5a7c2d3..3b903f6bce98 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -1938,14 +1938,17 @@ void xfs_free_buftarg( struct xfs_buftarg *btp) { + struct block_device *bdev = btp->bt_bdev; + unregister_shrinker(&btp->bt_shrinker); ASSERT(percpu_counter_sum(&btp->bt_io_count) == 0); percpu_counter_destroy(&btp->bt_io_count); list_lru_destroy(&btp->bt_lru); - blkdev_issue_flush(btp->bt_bdev); - invalidate_bdev(btp->bt_bdev); fs_put_dax(btp->bt_daxdev, btp->bt_mount); + /* the main block device is closed by kill_block_super */ + if (bdev != btp->bt_mount->m_super->s_bdev) + blkdev_put(bdev, btp->bt_mount->m_super); kmem_free(btp); } diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c index 4b10edb2c972..c79eac048456 100644 --- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -377,17 +377,6 @@ disable_dax: return 0; } -static void -xfs_bdev_mark_dead( - struct block_device *bdev) -{ - xfs_force_shutdown(bdev->bd_holder, SHUTDOWN_DEVICE_REMOVED); -} - -static const struct blk_holder_ops xfs_holder_ops = { - .mark_dead = xfs_bdev_mark_dead, -}; - STATIC int xfs_blkdev_get( xfs_mount_t *mp, @@ -396,8 +385,8 @@ xfs_blkdev_get( { int error = 0; - *bdevp = blkdev_get_by_path(name, BLK_OPEN_READ | BLK_OPEN_WRITE, mp, - &xfs_holder_ops); + *bdevp = blkdev_get_by_path(name, BLK_OPEN_READ | BLK_OPEN_WRITE, + mp->m_super, &fs_holder_ops); if (IS_ERR(*bdevp)) { error = PTR_ERR(*bdevp); xfs_warn(mp, "Invalid device [%s], error=%d", name, error); @@ -407,31 +396,45 @@ xfs_blkdev_get( } STATIC void -xfs_blkdev_put( - struct xfs_mount *mp, - struct block_device *bdev) -{ - if (bdev) - blkdev_put(bdev, mp); -} - -STATIC void -xfs_close_devices( +xfs_shutdown_devices( struct xfs_mount *mp) { + /* + * Udev is triggered whenever anyone closes a block device or unmounts + * a file systemm on a block device. + * The default udev rules invoke blkid to read the fs super and create + * symlinks to the bdev under /dev/disk. For this, it uses buffered + * reads through the page cache. + * + * xfs_db also uses buffered reads to examine metadata. There is no + * coordination between xfs_db and udev, which means that they can run + * concurrently. Note there is no coordination between the kernel and + * blkid either. + * + * On a system with 64k pages, the page cache can cache the superblock + * and the root inode (and hence the root directory) with the same 64k + * page. If udev spawns blkid after the mkfs and the system is busy + * enough that it is still running when xfs_db starts up, they'll both + * read from the same page in the pagecache. + * + * The unmount writes updated inode metadata to disk directly. The XFS + * buffer cache does not use the bdev pagecache, so it needs to + * invalidate that pagecache on unmount. If the above scenario occurs, + * the pagecache no longer reflects what's on disk, xfs_db reads the + * stale metadata, and fails to find /a. Most of the time this succeeds + * because closing a bdev invalidates the page cache, but when processes + * race, everyone loses. + */ if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp) { - struct block_device *logdev = mp->m_logdev_targp->bt_bdev; - - xfs_free_buftarg(mp->m_logdev_targp); - xfs_blkdev_put(mp, logdev); + blkdev_issue_flush(mp->m_logdev_targp->bt_bdev); + invalidate_bdev(mp->m_logdev_targp->bt_bdev); } if (mp->m_rtdev_targp) { - struct block_device *rtdev = mp->m_rtdev_targp->bt_bdev; - - xfs_free_buftarg(mp->m_rtdev_targp); - xfs_blkdev_put(mp, rtdev); + blkdev_issue_flush(mp->m_rtdev_targp->bt_bdev); + invalidate_bdev(mp->m_rtdev_targp->bt_bdev); } - xfs_free_buftarg(mp->m_ddev_targp); + blkdev_issue_flush(mp->m_ddev_targp->bt_bdev); + invalidate_bdev(mp->m_ddev_targp->bt_bdev); } /* @@ -448,17 +451,24 @@ STATIC int xfs_open_devices( struct xfs_mount *mp) { - struct block_device *ddev = mp->m_super->s_bdev; + struct super_block *sb = mp->m_super; + struct block_device *ddev = sb->s_bdev; struct block_device *logdev = NULL, *rtdev = NULL; int error; /* + * blkdev_put() can't be called under s_umount, see the comment + * in get_tree_bdev() for more details + */ + up_write(&sb->s_umount); + + /* * Open real time and log devices - order is important. */ if (mp->m_logname) { error = xfs_blkdev_get(mp, mp->m_logname, &logdev); if (error) - return error; + goto out_relock; } if (mp->m_rtname) { @@ -496,7 +506,10 @@ xfs_open_devices( mp->m_logdev_targp = mp->m_ddev_targp; } - return 0; + error = 0; +out_relock: + down_write(&sb->s_umount); + return error; out_free_rtdev_targ: if (mp->m_rtdev_targp) @@ -504,11 +517,12 @@ xfs_open_devices( out_free_ddev_targ: xfs_free_buftarg(mp->m_ddev_targp); out_close_rtdev: - xfs_blkdev_put(mp, rtdev); + if (rtdev) + blkdev_put(rtdev, sb); out_close_logdev: if (logdev && logdev != ddev) - xfs_blkdev_put(mp, logdev); - return error; + blkdev_put(logdev, sb); + goto out_relock; } /* @@ -758,6 +772,17 @@ static void xfs_mount_free( struct xfs_mount *mp) { + /* + * Free the buftargs here because blkdev_put needs to be called outside + * of sb->s_umount, which is held around the call to ->put_super. + */ + if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp) + xfs_free_buftarg(mp->m_logdev_targp); + if (mp->m_rtdev_targp) + xfs_free_buftarg(mp->m_rtdev_targp); + if (mp->m_ddev_targp) + xfs_free_buftarg(mp->m_ddev_targp); + kfree(mp->m_rtname); kfree(mp->m_logname); kmem_free(mp); @@ -1133,10 +1158,6 @@ xfs_fs_put_super( { struct xfs_mount *mp = XFS_M(sb); - /* if ->fill_super failed, we have no mount to tear down */ - if (!sb->s_fs_info) - return; - xfs_notice(mp, "Unmounting Filesystem %pU", &mp->m_sb.sb_uuid); xfs_filestream_unmount(mp); xfs_unmountfs(mp); @@ -1147,10 +1168,7 @@ xfs_fs_put_super( xfs_inodegc_free_percpu(mp); xfs_destroy_percpu_counters(mp); xfs_destroy_mount_workqueues(mp); - xfs_close_devices(mp); - - sb->s_fs_info = NULL; - xfs_mount_free(mp); + xfs_shutdown_devices(mp); } static long @@ -1492,7 +1510,7 @@ xfs_fs_fill_super( error = xfs_fs_validate_params(mp); if (error) - goto out_free_names; + return error; sb_min_blocksize(sb, BBSIZE); sb->s_xattr = xfs_xattr_handlers; @@ -1519,11 +1537,11 @@ xfs_fs_fill_super( error = xfs_open_devices(mp); if (error) - goto out_free_names; + return error; error = xfs_init_mount_workqueues(mp); if (error) - goto out_close_devices; + goto out_shutdown_devices; error = xfs_init_percpu_counters(mp); if (error) @@ -1737,11 +1755,8 @@ xfs_fs_fill_super( xfs_destroy_percpu_counters(mp); out_destroy_workqueues: xfs_destroy_mount_workqueues(mp); - out_close_devices: - xfs_close_devices(mp); - out_free_names: - sb->s_fs_info = NULL; - xfs_mount_free(mp); + out_shutdown_devices: + xfs_shutdown_devices(mp); return error; out_unmount: @@ -1934,7 +1949,8 @@ xfs_fs_reconfigure( return 0; } -static void xfs_fs_free( +static void +xfs_fs_free( struct fs_context *fc) { struct xfs_mount *mp = fc->s_fs_info; @@ -2003,12 +2019,20 @@ static int xfs_init_fs_context( return 0; } +static void +xfs_kill_sb( + struct super_block *sb) +{ + kill_block_super(sb); + xfs_mount_free(XFS_M(sb)); +} + static struct file_system_type xfs_fs_type = { .owner = THIS_MODULE, .name = "xfs", .init_fs_context = xfs_init_fs_context, .parameters = xfs_fs_parameters, - .kill_sb = kill_block_super, + .kill_sb = xfs_kill_sb, .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP | FS_MGTIME, }; MODULE_ALIAS_FS("xfs"); diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 0bad62cca3d0..d5c5e59ddbd2 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -52,7 +52,6 @@ struct block_device { atomic_t bd_openers; spinlock_t bd_size_lock; /* for bd_inode->i_size updates */ struct inode * bd_inode; /* will die */ - struct super_block * bd_super; void * bd_claiming; void * bd_holder; const struct blk_holder_ops *bd_holder_ops; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 87d94be7825a..83ce87354e9a 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -750,7 +750,8 @@ static inline int bdev_read_only(struct block_device *bdev) } bool set_capacity_and_notify(struct gendisk *disk, sector_t size); -bool disk_force_media_change(struct gendisk *disk, unsigned int events); +void disk_force_media_change(struct gendisk *disk); +void bdev_mark_dead(struct block_device *bdev, bool surprise); void add_disk_randomness(struct gendisk *disk) __latent_entropy; void rand_initialize_disk(struct gendisk *disk); @@ -809,7 +810,6 @@ int __register_blkdev(unsigned int major, const char *name, void unregister_blkdev(unsigned int major, const char *name); bool disk_check_media_change(struct gendisk *disk); -int __invalidate_device(struct block_device *bdev, bool kill_dirty); void set_capacity(struct gendisk *disk, sector_t size); #ifdef CONFIG_BLOCK_HOLDER_DEPRECATED @@ -1460,9 +1460,16 @@ void blkdev_show(struct seq_file *seqf, off_t offset); #endif struct blk_holder_ops { - void (*mark_dead)(struct block_device *bdev); + void (*mark_dead)(struct block_device *bdev, bool surprise); + + /* + * Sync the file system mounted on the block device. + */ + void (*sync)(struct block_device *bdev); }; +extern const struct blk_holder_ops fs_holder_ops; + /* * Return the correct open flags for blkdev_get_by_* for super block flags * as stored in sb->s_flags. @@ -1521,8 +1528,6 @@ static inline int early_lookup_bdev(const char *pathname, dev_t *dev) } #endif /* CONFIG_BLOCK */ -int fsync_bdev(struct block_device *bdev); - int freeze_bdev(struct block_device *bdev); int thaw_bdev(struct block_device *bdev); diff --git a/include/linux/fs.h b/include/linux/fs.h index 0ffb996c2af3..4e270f3ed58e 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1095,6 +1095,8 @@ extern int send_sigurg(struct fown_struct *fown); #define SB_LAZYTIME BIT(25) /* Update the on-disk [acm]times lazily */ /* These sb flags are internal to the kernel */ +#define SB_DEAD BIT(21) +#define SB_DYING BIT(24) #define SB_SUBMOUNT BIT(26) #define SB_FORCE BIT(27) #define SB_NOSEC BIT(28) @@ -1147,7 +1149,8 @@ enum { #define SB_FREEZE_LEVELS (SB_FREEZE_COMPLETE - 1) struct sb_writers { - int frozen; /* Is sb frozen? */ + unsigned short frozen; /* Is sb frozen? */ + unsigned short freeze_holders; /* Who froze fs? */ struct percpu_rw_semaphore rw_sem[SB_FREEZE_LEVELS]; }; @@ -1982,6 +1985,10 @@ extern loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos, struct file *dst_file, loff_t dst_pos, loff_t len, unsigned int remap_flags); +enum freeze_holder { + FREEZE_HOLDER_KERNEL = (1U << 0), + FREEZE_HOLDER_USERSPACE = (1U << 1), +}; struct super_operations { struct inode *(*alloc_inode)(struct super_block *sb); @@ -1994,9 +2001,9 @@ struct super_operations { void (*evict_inode) (struct inode *); void (*put_super) (struct super_block *); int (*sync_fs)(struct super_block *sb, int wait); - int (*freeze_super) (struct super_block *); + int (*freeze_super) (struct super_block *, enum freeze_holder who); int (*freeze_fs) (struct super_block *); - int (*thaw_super) (struct super_block *); + int (*thaw_super) (struct super_block *, enum freeze_holder who); int (*unfreeze_fs) (struct super_block *); int (*statfs) (struct dentry *, struct kstatfs *); int (*remount_fs) (struct super_block *, int *, char *); @@ -2382,8 +2389,8 @@ extern int unregister_filesystem(struct file_system_type *); extern int vfs_statfs(const struct path *, struct kstatfs *); extern int user_statfs(const char __user *, struct kstatfs *); extern int fd_statfs(int, struct kstatfs *); -extern int freeze_super(struct super_block *super); -extern int thaw_super(struct super_block *super); +int freeze_super(struct super_block *super, enum freeze_holder who); +int thaw_super(struct super_block *super, enum freeze_holder who); extern __printf(2, 3) int super_setup_bdi_name(struct super_block *sb, char *fmt, ...); extern int super_setup_bdi(struct super_block *sb); @@ -3055,7 +3062,6 @@ extern int vfs_readlink(struct dentry *, char __user *, int); extern struct file_system_type *get_filesystem(struct file_system_type *fs); extern void put_filesystem(struct file_system_type *fs); extern struct file_system_type *get_fs_type(const char *name); -extern struct super_block *get_super(struct block_device *); extern struct super_block *get_active_super(struct block_device *bdev); extern void drop_super(struct super_block *sb); extern void drop_super_exclusive(struct super_block *sb); diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h index a33a3b1d9016..96332db693d5 100644 --- a/include/linux/fs_context.h +++ b/include/linux/fs_context.h @@ -156,6 +156,8 @@ extern int get_tree_keyed(struct fs_context *fc, struct fs_context *fc), void *key); +int setup_bdev_super(struct super_block *sb, int sb_flags, + struct fs_context *fc); extern int get_tree_bdev(struct fs_context *fc, int (*fill_super)(struct super_block *sb, struct fs_context *fc)); |