Commit fa4d885a authored Sep 15, 2017 by Adam Borowski Committed by David Sterba Nov 01, 2017

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
a7164fa4 ("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>

parent f51d2b59

fs/btrfs/compression.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}

fs/btrfs/super.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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");