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authorFilipe Manana <fdmanana@suse.com>2019-03-26 10:49:56 +0000
committerDavid Sterba <dsterba@suse.com>2019-03-28 18:10:27 +0100
commitf35f06c35560a86e841631f0243b83a984dc11a9 (patch)
tree5be85f835ef5e28c2e42db529d8e6c99ed12e08b /fs
parent0ccc3876e4b2a1559a4dbe3126dda4459d38a83b (diff)
downloadlinux-stericsson-f35f06c35560a86e841631f0243b83a984dc11a9.tar.gz
Btrfs: do not allow trimming when a fs is mounted with the nologreplay option
Whan a filesystem is mounted with the nologreplay mount option, which requires it to be mounted in RO mode as well, we can not allow discard on free space inside block groups, because log trees refer to extents that are not pinned in a block group's free space cache (pinning the extents is precisely the first phase of replaying a log tree). So do not allow the fitrim ioctl to do anything when the filesystem is mounted with the nologreplay option, because later it can be mounted RW without that option, which causes log replay to happen and result in either a failure to replay the log trees (leading to a mount failure), a crash or some silent corruption. Reported-by: Darrick J. Wong <darrick.wong@oracle.com> Fixes: 96da09192cda ("btrfs: Introduce new mount option to disable tree log replay") CC: stable@vger.kernel.org # 4.9+ Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/ioctl.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index ec2d8919e7fb..cd4e693406a0 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -501,6 +501,16 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
+ /*
+ * If the fs is mounted with nologreplay, which requires it to be
+ * mounted in RO mode as well, we can not allow discard on free space
+ * inside block groups, because log trees refer to extents that are not
+ * pinned in a block group's free space cache (pinning the extents is
+ * precisely the first phase of replaying a log tree).
+ */
+ if (btrfs_test_opt(fs_info, NOLOGREPLAY))
+ return -EROFS;
+
rcu_read_lock();
list_for_each_entry_rcu(device, &fs_info->fs_devices->devices,
dev_list) {