diff options
| author | David Sterba <dsterba@suse.com> | 2018-06-19 16:37:36 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2018-08-06 13:12:47 +0200 |
| commit | 899f9307c33ce4758c30a076b10ed54d5c91c6e7 (patch) | |
| tree | a4a20c74583fb1d5f4527977faa947670562f6de /fs/btrfs/super.c | |
| parent | 7bcb8164ad9435068d9bc3b83b8a002c64d63ff6 (diff) | |
btrfs: lift uuid_mutex to callers of btrfs_scan_one_device
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>
Diffstat (limited to 'fs/btrfs/super.c')
| -rw-r--r-- | fs/btrfs/super.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 39d8e39b2fe1..0b6567f0c63d 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -915,8 +915,10 @@ 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; @@ -1537,7 +1539,9 @@ 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; @@ -2232,15 +2236,21 @@ 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); |