diff options
| author | Christoph Hellwig <hch@lst.de> | 2009-08-03 23:28:06 +0200 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2009-09-24 07:47:39 -0400 |
| commit | 4fadd7bb20a1e7c774ed88dc703d8fbcd00ff917 (patch) | |
| tree | a6f3df6f19d27e81f35a93f8858b73bd4273f420 /fs | |
| parent | 1ba50bbe93ebb98e83b174a85eff76af430c4e5b (diff) | |
| download | linux-4fadd7bb20a1e7c774ed88dc703d8fbcd00ff917.tar.bz2 | |
freeze_bdev: kill bd_mount_sem
Now that we have the freeze count there is not much reason for bd_mount_sem
anymore. The actual freeze/thaw operations are serialized using the
bd_fsfreeze_mutex, and the only other place we take bd_mount_sem is
get_sb_bdev which tries to prevent mounting a filesystem while the block
device is frozen. Instead of add a check for bd_fsfreeze_count and
return -EBUSY if a filesystem is frozen. While that is a change in user
visible behaviour a failing mount is much better for this case rather
than having the mount process stuck uninterruptible for a long time.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/block_dev.c | 8 | ||||
| -rw-r--r-- | fs/super.c | 9 |
2 files changed, 8 insertions, 9 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 5d1ed50bd46c..22506eb4a58e 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -216,8 +216,6 @@ EXPORT_SYMBOL(fsync_bdev); * freeze_bdev -- lock a filesystem and force it into a consistent state * @bdev: blockdevice to lock * - * This takes the block device bd_mount_sem to make sure no new mounts - * happen on bdev until thaw_bdev() is called. * If a superblock is found on this device, we take the s_umount semaphore * on it to make sure nobody unmounts until the snapshot creation is done. * The reference counter (bd_fsfreeze_count) guarantees that only the last @@ -240,7 +238,6 @@ struct super_block *freeze_bdev(struct block_device *bdev) } bdev->bd_fsfreeze_count++; - down(&bdev->bd_mount_sem); sb = get_super(bdev); if (sb && !(sb->s_flags & MS_RDONLY)) { sb->s_frozen = SB_FREEZE_WRITE; @@ -260,7 +257,6 @@ struct super_block *freeze_bdev(struct block_device *bdev) "VFS:Filesystem freeze failed\n"); sb->s_frozen = SB_UNFROZEN; drop_super(sb); - up(&bdev->bd_mount_sem); bdev->bd_fsfreeze_count--; mutex_unlock(&bdev->bd_fsfreeze_mutex); return ERR_PTR(error); @@ -271,7 +267,7 @@ struct super_block *freeze_bdev(struct block_device *bdev) sync_blockdev(bdev); mutex_unlock(&bdev->bd_fsfreeze_mutex); - return sb; /* thaw_bdev releases s->s_umount and bd_mount_sem */ + return sb; /* thaw_bdev releases s->s_umount */ } EXPORT_SYMBOL(freeze_bdev); @@ -321,7 +317,6 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb) drop_super(sb); } - up(&bdev->bd_mount_sem); mutex_unlock(&bdev->bd_fsfreeze_mutex); return 0; } @@ -430,7 +425,6 @@ static void init_once(void *foo) memset(bdev, 0, sizeof(*bdev)); mutex_init(&bdev->bd_mutex); - sema_init(&bdev->bd_mount_sem, 1); INIT_LIST_HEAD(&bdev->bd_inodes); INIT_LIST_HEAD(&bdev->bd_list); #ifdef CONFIG_SYSFS diff --git a/fs/super.c b/fs/super.c index 4906e2d8f400..1cb26a3e3df0 100644 --- a/fs/super.c +++ b/fs/super.c @@ -743,9 +743,14 @@ int get_sb_bdev(struct file_system_type *fs_type, * will protect the lockfs code from trying to start a snapshot * while we are mounting */ - down(&bdev->bd_mount_sem); + 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, bdev); - up(&bdev->bd_mount_sem); + mutex_unlock(&bdev->bd_fsfreeze_mutex); if (IS_ERR(s)) goto error_s; |