| Message ID | 20200803195501.30528-1-marcos@mpdesouza.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: super.c: Set compress_level=0 when using compress=lzo | expand |
On Mon, Aug 03, 2020 at 04:55:01PM -0300, Marcos Paulo de Souza wrote: > From: Marcos Paulo de Souza <mpdesouza@suse.com> > > Currently a user can set mount "-o compress" which will set the > compression algorithm to zlib, and use the default compress level for > zlib (3): > > relatime,compress=zlib:3,space_cache > > If the user remounts the fs using "-o compress=lzo", then the old > compress_level is used: > > relatime,compress=lzo:3,space_cache > > But lzo does not exposes any tunable compress level. The same happens if we set > any compress argument with different level, even with zstd. > > Fix this issue by resetting the compress_level when compress=lzo is specified. > With the fix applied, lzo is shown without compress level, even after remounting > from zlib or zstd: > > relatime,compress=lzo,space_cache > > Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com> > --- > > I found this issue while testing mount options. Should we tag this fix for > stable since the introduction of the compress_level, or is it no worthy? I'll tag it for stable, it's user-visible and confusing. Thanks.
On Mon, Aug 03, 2020 at 04:55:01PM -0300, Marcos Paulo de Souza wrote: > --- a/fs/btrfs/super.c > +++ b/fs/btrfs/super.c > @@ -614,6 +614,8 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options, > } else if (strncmp(args[0].from, "lzo", 3) == 0) { > compress_type = "lzo"; > info->compress_type = BTRFS_COMPRESS_LZO; > + /* lzo does not expose compression levels */ > + info->compress_level = 0; I had that as a fixup in patches fixing the other message errors, with info->compress_level = 1. With level 0 it'll print btrfs_info(info, "%s %s compression, level %d", (compress_force) ? "force" : "use", compress_type, info->compress_level); "use lzo compression, level 0" Which might be confusing as well, but super.c:btrfs_show_options will not print the level in that case so I think it's fine with 0.
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index a034ed52b5f6..dd2f05f9d6c6 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -614,6 +614,8 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options, } else if (strncmp(args[0].from, "lzo", 3) == 0) { compress_type = "lzo"; info->compress_type = BTRFS_COMPRESS_LZO; + /* lzo does not expose compression levels */ + info->compress_level = 0; btrfs_set_opt(info->mount_opt, COMPRESS); btrfs_clear_opt(info->mount_opt, NODATACOW); btrfs_clear_opt(info->mount_opt, NODATASUM);