diff options
| author | David Sterba <dsterba@suse.com> | 2018-06-19 16:37:36 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-15 09:46:56 +0200 |
| commit | 71ddab54bee5c571647fd5ed9bb9be9db305f7c1 (patch) | |
| tree | 888651583bf90c8137a664719a4d5002f760115f /fs | |
| parent | 40ce21951aab62b8cdd6d2b852154d6fe9f11163 (diff) | |
btrfs: lift uuid_mutex to callers of btrfs_scan_one_device
[ Upstream commit 899f9307c33ce4758c30a076b10ed54d5c91c6e7 ]
Prepartory work to fix race between mount and device scan.
The callers will have to manage the critical section, eg. mount wants to
scan and then call btrfs_open_devices without the ioctl scan walking in
and modifying the fs devices in the meantime.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/super.c | 12 | ||||
| -rw-r--r-- | fs/btrfs/volumes.c | 4 |
2 files changed, 13 insertions, 3 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index fdda3cd8a921..b00e88f746cb 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -917,8 +917,10 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags, error = -ENOMEM; goto out; } + mutex_lock(&uuid_mutex); error = btrfs_scan_one_device(device_name, flags, holder, fs_devices); + mutex_unlock(&uuid_mutex); kfree(device_name); if (error) goto out; @@ -1539,7 +1541,9 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type, return ERR_PTR(error); } + mutex_lock(&uuid_mutex); error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices); + mutex_unlock(&uuid_mutex); if (error) goto error_sec_opts; @@ -2236,15 +2240,21 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd, switch (cmd) { case BTRFS_IOC_SCAN_DEV: + mutex_lock(&uuid_mutex); ret = btrfs_scan_one_device(vol->name, FMODE_READ, &btrfs_root_fs_type, &fs_devices); + mutex_unlock(&uuid_mutex); break; case BTRFS_IOC_DEVICES_READY: + mutex_lock(&uuid_mutex); ret = btrfs_scan_one_device(vol->name, FMODE_READ, &btrfs_root_fs_type, &fs_devices); - if (ret) + if (ret) { + mutex_unlock(&uuid_mutex); break; + } ret = !(fs_devices->num_devices == fs_devices->total_devices); + mutex_unlock(&uuid_mutex); break; case BTRFS_IOC_GET_SUPPORTED_FEATURES: ret = btrfs_ioctl_get_supported_features((void __user*)arg); diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 6e6b4f2c85ad..5304b8d6ceb8 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1241,6 +1241,8 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, int ret = 0; u64 bytenr; + lockdep_assert_held(&uuid_mutex); + /* * we would like to check all the supers, but that would make * a btrfs mount succeed after a mkfs from a different FS. @@ -1259,7 +1261,6 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, goto error_bdev_put; } - mutex_lock(&uuid_mutex); device = device_list_add(path, disk_super, &new_device_added); if (IS_ERR(device)) { ret = PTR_ERR(device); @@ -1268,7 +1269,6 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, if (new_device_added) btrfs_free_stale_devices(path, device); } - mutex_unlock(&uuid_mutex); btrfs_release_disk_super(page); |