btrfs: prepare for extensions in compression options

This is a minimal patch intended to be backported to older kernels.
We're going to extend the string specifying the compression method and
this would fail on kernels before that change (the string is compared
exactly).

Relax the string matching only to the prefix, ie. ignoring anything that
goes after "zlib" or "lzo", regardless of th format extension we decide
to use. This applies to the mount options and properties.

That way, patched old kernels could be booted on systems already
utilizing the new compression spec.

Applicable since commit 63541927c8, v3.14.

Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2017-07-17 18:11:10 +02:00
parent 1e20d1c45f
commit a7164fa4e0
2 changed files with 4 additions and 4 deletions

View File

@ -408,9 +408,9 @@ static int prop_compression_apply(struct inode *inode,
return 0;
}
if (!strncmp("lzo", value, len))
if (!strncmp("lzo", value, 3))
type = BTRFS_COMPRESS_LZO;
else if (!strncmp("zlib", value, len))
else if (!strncmp("zlib", value, 4))
type = BTRFS_COMPRESS_ZLIB;
else
return -EINVAL;

View File

@ -499,14 +499,14 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
btrfs_test_opt(info, FORCE_COMPRESS);
if (token == Opt_compress ||
token == Opt_compress_force ||
strcmp(args[0].from, "zlib") == 0) {
strncmp(args[0].from, "zlib", 4) == 0) {
compress_type = "zlib";
info->compress_type = BTRFS_COMPRESS_ZLIB;
btrfs_set_opt(info->mount_opt, COMPRESS);
btrfs_clear_opt(info->mount_opt, NODATACOW);
btrfs_clear_opt(info->mount_opt, NODATASUM);
no_compress = 0;
} else if (strcmp(args[0].from, "lzo") == 0) {
} else if (strncmp(args[0].from, "lzo", 3) == 0) {
compress_type = "lzo";
info->compress_type = BTRFS_COMPRESS_LZO;
btrfs_set_opt(info->mount_opt, COMPRESS);