| Message ID | 697674ea626a3d04218b02dbb12e07bdd851d3f0.1646983176.git.naohiro.aota@wdc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | protect relocation with sb_start_write | expand |
On Fri, Mar 11, 2022 at 04:38:05PM +0900, Naohiro Aota wrote: > btrfs_relocate_chunk() initiates new ordered extents. They can cause a > hang when a process is trying to thaw the filesystem. > > We should have called sb_start_write(), so the filesystem is not being > frozen. Add an ASSERT to check it is protected. > > Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> > --- > fs/btrfs/volumes.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index 0d27d8d35c7a..b558fd293ffa 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -3239,6 +3239,9 @@ int btrfs_relocate_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset) > u64 length; > int ret; > > + /* Assert we called sb_start_write(), not to race with FS freezing */ > + ASSERT(sb_write_started(fs_info->sb)); Does this pass the scenario of patch 1/4 (resuming balance on mount)? Because as commented in that patch, we have the sb_start_write() done in the mount task, and not by the task that actually runs balance - the balance kthread. Anyway, this change looks good, my concerns are only about patch 1/4. Thanks. > + > if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) { > btrfs_err(fs_info, > "relocate: not supported on extent tree v2 yet"); > -- > 2.35.1 >
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 0d27d8d35c7a..b558fd293ffa 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -3239,6 +3239,9 @@ int btrfs_relocate_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset) u64 length; int ret; + /* Assert we called sb_start_write(), not to race with FS freezing */ + ASSERT(sb_write_started(fs_info->sb)); + if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) { btrfs_err(fs_info, "relocate: not supported on extent tree v2 yet");
btrfs_relocate_chunk() initiates new ordered extents. They can cause a hang when a process is trying to thaw the filesystem. We should have called sb_start_write(), so the filesystem is not being frozen. Add an ASSERT to check it is protected. Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> --- fs/btrfs/volumes.c | 3 +++ 1 file changed, 3 insertions(+)