UBIFS: introduce compression mount options

It is very handy to be able to change default UBIFS compressor
via mount options. Introduce -o compr=<name> mount option support.
Currently only "none", "lzo" and "zlib" compressors are supported.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/fs/ubifs/sb.c b/fs/ubifs/sb.c
index 0f392351dc5a..c5da201ab54f 100644
--- a/fs/ubifs/sb.c
+++ b/fs/ubifs/sb.c
@@ -179,8 +179,11 @@ static int create_default_filesystem(struct ubifs_info *c)
         sup->fanout        = cpu_to_le32(DEFAULT_FANOUT);
         sup->lsave_cnt     = cpu_to_le32(c->lsave_cnt);
         sup->fmt_version   = cpu_to_le32(UBIFS_FORMAT_VERSION);
-        sup->default_compr = cpu_to_le16(UBIFS_COMPR_LZO);
         sup->time_gran     = cpu_to_le32(DEFAULT_TIME_GRAN);
+        if (c->mount_opts.override_compr)
+                sup->default_compr = cpu_to_le16(c->mount_opts.compr_type);
+        else
+                sup->default_compr = cpu_to_le16(UBIFS_COMPR_LZO);
 
         generate_random_uuid(sup->uuid);
 
@@ -582,16 +585,15 @@ int ubifs_read_superblock(struct ubifs_info *c)
         c->jhead_cnt     = le32_to_cpu(sup->jhead_cnt) + NONDATA_JHEADS_CNT;
         c->fanout        = le32_to_cpu(sup->fanout);
         c->lsave_cnt     = le32_to_cpu(sup->lsave_cnt);
-        c->default_compr = le16_to_cpu(sup->default_compr);
         c->rp_size       = le64_to_cpu(sup->rp_size);
         c->rp_uid        = le32_to_cpu(sup->rp_uid);
         c->rp_gid        = le32_to_cpu(sup->rp_gid);
         sup_flags        = le32_to_cpu(sup->flags);
+        if (!c->mount_opts.override_compr)
+                c->default_compr = le16_to_cpu(sup->default_compr);
 
         c->vfs_sb->s_time_gran = le32_to_cpu(sup->time_gran);
-
         memcpy(&c->uuid, &sup->uuid, 16);
-
         c->big_lpt = !!(sup_flags & UBIFS_FLG_BIGLPT);
 
         /* Automatically increase file system size to the maximum size */