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See http://www.infradead.org/rpr.html X-Headers-End: 1qRDz6-0004SZ-3q Subject: [f2fs-dev] [PATCH 04/12] btrfs: open block devices after superblock creation X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , linux-block@vger.kernel.org, linux-nilfs@vger.kernel.org, Jan Kara , linux-fsdevel@vger.kernel.org, "Darrick J. Wong" , Josef Bacik , linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, Chris Mason , Andreas Dilger , Jaegeuk Kim , David Sterba , Theodore Ts'o , linux-ext4@vger.kernel.org, Ryusuke Konishi , linux-btrfs@vger.kernel.org Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net Currently btrfs_mount_root opens the block devices before committing to allocating a super block. That creates problems for restricting the number of writers to a device, and also leads to a unusual and not very helpful holder (the fs_type). Reorganize the code to first look whether the superblock for a particular fsid does already exist and open the block devices only if it doesn't, mirror the recent changes to the VFS mount helpers. Signed-off-by: Christoph Hellwig --- fs/btrfs/super.c | 51 ++++++++++++++++++++++------------------------ fs/btrfs/volumes.c | 4 ++-- 2 files changed, 26 insertions(+), 29 deletions(-) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index b318bddefd5236..5980b5dcc6b163 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1434,10 +1434,8 @@ static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid, static struct dentry *btrfs_mount_root(struct file_system_type *fs_type, int flags, const char *device_name, void *data) { - struct block_device *bdev = NULL; struct super_block *s; struct btrfs_device *device = NULL; - struct btrfs_fs_devices *fs_devices = NULL; struct btrfs_fs_info *fs_info = NULL; void *new_sec_opts = NULL; int error = 0; @@ -1483,35 +1481,36 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type, error = PTR_ERR(device); goto error_fs_info; } - - fs_devices = device->fs_devices; - fs_info->fs_devices = fs_devices; - - error = btrfs_open_devices(fs_devices, sb_open_mode(flags), fs_type); + fs_info->fs_devices = device->fs_devices; mutex_unlock(&uuid_mutex); - if (error) - goto error_fs_info; - - if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) { - error = -EACCES; - goto error_close_devices; - } - bdev = fs_devices->latest_dev->bdev; s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC, fs_info); if (IS_ERR(s)) { error = PTR_ERR(s); - goto error_close_devices; + goto error_fs_info; } if (s->s_root) { - btrfs_close_devices(fs_devices); btrfs_free_fs_info(fs_info); if ((flags ^ s->s_flags) & SB_RDONLY) error = -EBUSY; } else { - snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev); + struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; + + error = btrfs_open_devices(fs_devices, sb_open_mode(flags), + fs_type); + if (error) + goto out_deactivate; + + if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) { + error = -EACCES; + btrfs_close_devices(fs_info->fs_devices); + goto out_deactivate; + } + + snprintf(s->s_id, sizeof(s->s_id), "%pg", + fs_devices->latest_dev->bdev); shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s", fs_type->name, s->s_id); btrfs_sb(s)->bdev_holder = fs_type; @@ -1519,21 +1518,19 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type, } if (!error) error = security_sb_set_mnt_opts(s, new_sec_opts, 0, NULL); + if (error) + goto out_deactivate; security_free_mnt_opts(&new_sec_opts); - if (error) { - deactivate_locked_super(s); - return ERR_PTR(error); - } - return dget(s->s_root); -error_close_devices: - btrfs_close_devices(fs_devices); -error_fs_info: - btrfs_free_fs_info(fs_info); +out_deactivate: + deactivate_locked_super(s); error_sec_opts: security_free_mnt_opts(&new_sec_opts); return ERR_PTR(error); +error_fs_info: + btrfs_free_fs_info(fs_info); + goto error_sec_opts; } /* diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 8246578c70f55b..88e9daae5e74ed 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1269,7 +1269,6 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, { int ret; - lockdep_assert_held(&uuid_mutex); /* * The device_list_mutex cannot be taken here in case opening the * underlying device takes further locks like open_mutex. @@ -1277,7 +1276,7 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, * We also don't need the lock here as this is called during mount and * exclusion is provided by uuid_mutex */ - + mutex_lock(&uuid_mutex); if (fs_devices->opened) { fs_devices->opened++; ret = 0; @@ -1285,6 +1284,7 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, list_sort(NULL, &fs_devices->devices, devid_cmp); ret = open_fs_devices(fs_devices, flags, holder); } + mutex_unlock(&uuid_mutex); return ret; }