| Message ID | 4d68f9e1e230dba0dfa70fb664540a962e0ae055.1728920737.git.fdmanana@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: clear force-compress on remount when compress mount option is given | expand |
On Mon, Oct 14, 2024 at 04:46:30PM +0100, fdmanana@kernel.org wrote: > From: Filipe Manana <fdmanana@suse.com> > > After the migration to use fs context for processing mount options we had > a slight change in the semantics for remounting a filesystem that was > mounted with compress-force. Before we could clear compress-force by > passing only "-o compress[=algo]" during a remount, but after that change > that does not work anymore, force-compress is still present and one needs > to pass "-o compress-force=no,compress[=algo]" to the mount command. > > Example, when running on a kernel 6.8+: > > $ mount -o compress-force=zlib:9 /dev/sdi /mnt/sdi > $ mount | grep sdi > /dev/sdi on /mnt/sdi type btrfs (rw,relatime,compress-force=zlib:9,discard=async,space_cache=v2,subvolid=5,subvol=/) > > $ mount -o remount,compress=zlib:5 /mnt/sdi > $ mount | grep $sdi > /dev/sdi on /mnt/sdi type btrfs (rw,relatime,compress-force=zlib:5,discard=async,space_cache=v2,subvolid=5,subvol=/) > > On a 6.7 kernel (or older): > > $ mount -o compress-force=zlib:9 /dev/sdi /mnt/sdi > $ mount | grep sdi > /dev/sdi on /mnt/sdi type btrfs (rw,relatime,compress-force=zlib:9,discard=async,space_cache=v2,subvolid=5,subvol=/) > > $ mount -o remount,compress=zlib:5 /mnt/sdi > $ mount | grep sdi > /dev/sdi on /mnt/sdi type btrfs (rw,relatime,compress=zlib:5,discard=async,space_cache=v2,subvolid=5,subvol=/) > > So update btrfs_parse_param() to clear "compress-force" when "compress" is > given, providing the same semantics as kernel 6.7 and older. > > Reported-by: Roman Mamedov <rm@romanrm.net> > Link: https://lore.kernel.org/linux-btrfs/20241014182416.13d0f8b0@nvm/ > CC: stable@vger.kernel.org # 6.8+ > Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index e8a5bf4af918..a4711640c0b4 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -340,6 +340,15 @@ static int btrfs_parse_param(struct fs_context *fc, struct fs_parameter *param) fallthrough; case Opt_compress: case Opt_compress_type: + /* + * Provide the same semantics as older kernels that don't use fs + * context, specifying the "compress" option clears + * "force-compress" without the need to pass + * "compress-force=[no|none]" before specifying "compress". + */ + if (opt != Opt_compress_force && opt != Opt_compress_force_type) + btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS); + if (opt == Opt_compress || opt == Opt_compress_force) { ctx->compress_type = BTRFS_COMPRESS_ZLIB; ctx->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;