btrfs: allow setting zlib compression level via :9

This is bikeshedding, but it seems people are drastically more likely to
understand "zlib:9" as compression level rather than an algorithm
version compared to "zlib9".

Based on feedback on the mailinglist, the ":9" will be the only accepted
syntax. The level must be a single digit. Unrecognized format will
result to the default, for forward compatibility in a similar way the
compression algorithm specifier was relaxed in commit
a7164fa4e0 ("btrfs: prepare for extensions in compression
options").

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Reviewed-by: David Sterba <dsterba@suse.com>
[ tighten the accepted format ]
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Adam Borowski 2017-09-15 17:36:58 +02:00 committed by David Sterba
parent f51d2b5912
commit fa4d885a48
2 changed files with 4 additions and 3 deletions

View File

@ -1111,8 +1111,9 @@ unsigned int btrfs_compress_str2level(const char *str)
if (strncmp(str, "zlib", 4) != 0)
return 0;
if ('1' <= str[4] && str[4] <= '9' )
return str[4] - '0';
/* Accepted form: zlib:1 up to zlib:9 and nothing left after the number */
if (str[4] == ':' && '1' <= str[5] && str[5] <= '9' && str[6] == 0)
return str[5] - '0';
return 0;
}

View File

@ -1261,7 +1261,7 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
else
seq_printf(seq, ",compress=%s", compress_type);
if (info->compress_level)
seq_printf(seq, "%d", info->compress_level);
seq_printf(seq, ":%d", info->compress_level);
}
if (btrfs_test_opt(info, NOSSD))
seq_puts(seq, ",nossd");