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authorFilipe Manana <fdmanana@suse.com>2019-03-26 10:49:56 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-04-17 08:36:46 +0200
commit1ac411b49fd636a53d3c117caa71af44a604859d (patch)
tree4ee5e2741c7012ce63de2ac522913ee933cf2681
parentf4a40058ac9e6447a05626a0ba51ffc58a834f7b (diff)
Btrfs: do not allow trimming when a fs is mounted with the nologreplay option
commit f35f06c35560a86e841631f0243b83a984dc11a9 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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 242584a0d3b5..a67143c579aa 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -385,6 +385,16 @@ 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) {