4.18-stable review patch. If anyone has any objections, please let me know.
------------------ From: David Sterba <[email protected]> [ Upstream commit 5139cff598d42b1e531f40c84691a7e945f04553 ] Prepartory work to fix race between mount and device scan. btrfs_parse_early_options calls the device scan from mount and we'll need to let mount completely manage the critical section. Reviewed-by: Anand Jain <[email protected]> Signed-off-by: David Sterba <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/btrfs/super.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -892,6 +892,8 @@ static int btrfs_parse_early_options(con char *device_name, *opts, *orig, *p; int error = 0; + lockdep_assert_held(&uuid_mutex); + if (!options) return 0; @@ -917,10 +919,8 @@ static int btrfs_parse_early_options(con 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; @@ -1528,8 +1528,10 @@ static struct dentry *btrfs_mount_root(s if (!(flags & SB_RDONLY)) mode |= FMODE_WRITE; + mutex_lock(&uuid_mutex); error = btrfs_parse_early_options(data, mode, fs_type, &fs_devices); + mutex_unlock(&uuid_mutex); if (error) { return ERR_PTR(error); }
