jffs2: implement mount option parsing and compression overriding
Currently jffs2 has compile-time constants (and .config options)
controlling whether or not the various compression/decompression
drivers are built in and enabled. This is fine for embedded
systems, but it clashes with distribution kernels. Distro kernels
tend to turn on everything; this causes OpenFirmware to fall
over, as it understands ZLIB-compressed inodes. Booting a kernel
that has LZO compression enabled, writing to the boot partition,
and then rebooting causes OFW to fail to read the kernel from
the filesystem. This is because LZO compression has priority
when writing new data to jffs2, if LZO is enabled.
This patch adds mount option parsing, and a single supported
option ("compr=none"). This adds the flexibility of being
able to specify which compressor overrides on a per-superblock
basis. For now, we can simply disable compression;
additional flexibility coming soon.
v2: kill some printks, and implement show_options as suggested
by Artem Bityutskiy.
Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
diff --git a/fs/jffs2/jffs2_fs_sb.h b/fs/jffs2/jffs2_fs_sb.h
index 0bc6a6c..55a0c1d 100644
--- a/fs/jffs2/jffs2_fs_sb.h
+++ b/fs/jffs2/jffs2_fs_sb.h
@@ -29,6 +29,11 @@
struct jffs2_inodirty;
+struct jffs2_mount_opts {
+ bool override_compr;
+ unsigned int compr;
+};
+
/* A struct for the overall file system control. Pointers to
jffs2_sb_info structs are named `c' in the source code.
Nee jffs_control
@@ -126,6 +131,7 @@
#endif
struct jffs2_summary *summary; /* Summary information */
+ struct jffs2_mount_opts mount_opts;
#ifdef CONFIG_JFFS2_FS_XATTR
#define XATTRINDEX_HASHSIZE (57)