5 files changed, 112 insertions, 4 deletions

diff --git a/fs/jffs2/compr.c b/fs/jffs2/compr.c
index de4247021d25..97bc74db2c96 100644
--- a/fs/jffs2/compr.c
+++ b/fs/jffs2/compr.c
@@ -76,13 +76,18 @@ uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
                         uint32_t *datalen, uint32_t *cdatalen)
 {
         int ret = JFFS2_COMPR_NONE;
-        int compr_ret;
+        int mode, compr_ret;
         struct jffs2_compressor *this, *best=NULL;
         unsigned char *output_buf = NULL, *tmp_buf;
         uint32_t orig_slen, orig_dlen;
         uint32_t best_slen=0, best_dlen=0;
 
-        switch (jffs2_compression_mode) {
+        if (c->mount_opts.override_compr)
+                mode = c->mount_opts.compr;
+        else
+                mode = jffs2_compression_mode;
+
+        switch (mode) {
         case JFFS2_COMPR_MODE_NONE:
                 break;
         case JFFS2_COMPR_MODE_PRIORITY:
diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c
index bbcb9755dd2b..5d54b4ed1b6c 100644
--- a/fs/jffs2/fs.c
+++ b/fs/jffs2/fs.c
@@ -379,7 +379,7 @@ void jffs2_dirty_inode(struct inode *inode, int flags)
         jffs2_do_setattr(inode, &iattr);
 }
 
-int jffs2_remount_fs (struct super_block *sb, int *flags, char *data)
+int jffs2_do_remount_fs(struct super_block *sb, int *flags, char *data)
 {
         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 
diff --git a/fs/jffs2/jffs2_fs_sb.h b/fs/jffs2/jffs2_fs_sb.h
index 0bc6a6c80a56..55a0c1dceadf 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 @@ struct jffs2_sb_info {
 #endif
 
         struct jffs2_summary *summary;          /* Summary information */
+        struct jffs2_mount_opts mount_opts;
 
 #ifdef CONFIG_JFFS2_FS_XATTR
 #define XATTRINDEX_HASHSIZE     (57)
diff --git a/fs/jffs2/os-linux.h b/fs/jffs2/os-linux.h
index 6c1755c59c0f..ab65ee3ec858 100644
--- a/fs/jffs2/os-linux.h
+++ b/fs/jffs2/os-linux.h
@@ -176,7 +176,7 @@ void jffs2_dirty_inode(struct inode *inode, int flags);
 struct inode *jffs2_new_inode (struct inode *dir_i, umode_t mode,
                                struct jffs2_raw_inode *ri);
 int jffs2_statfs (struct dentry *, struct kstatfs *);
-int jffs2_remount_fs (struct super_block *, int *, char *);
+int jffs2_do_remount_fs(struct super_block *, int *, char *);
 int jffs2_do_fill_super(struct super_block *sb, void *data, int silent);
 void jffs2_gc_release_inode(struct jffs2_sb_info *c,
                             struct jffs2_inode_info *f);
diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
index 853b8e300084..40f6e6385fd1 100644
--- a/fs/jffs2/super.c
+++ b/fs/jffs2/super.c
@@ -17,11 +17,13 @@
 #include <linux/fs.h>
 #include <linux/err.h>
 #include <linux/mount.h>
+#include <linux/parser.h>
 #include <linux/jffs2.h>
 #include <linux/pagemap.h>
 #include <linux/mtd/super.h>
 #include <linux/ctype.h>
 #include <linux/namei.h>
+#include <linux/seq_file.h>
 #include <linux/exportfs.h>
 #include "compr.h"
 #include "nodelist.h"
@@ -75,6 +77,29 @@ static void jffs2_write_super(struct super_block *sb)
         unlock_super(sb);
 }
 
+static const char *jffs2_compr_name(unsigned int compr)
+{
+        switch (compr) {
+        case JFFS2_COMPR_MODE_NONE:
+                return "none";
+        default:
+                /* should never happen; programmer error */
+                WARN_ON(1);
+                return "";
+        }
+}
+
+static int jffs2_show_options(struct seq_file *s, struct vfsmount *mnt)
+{
+        struct jffs2_sb_info *c = JFFS2_SB_INFO(mnt->mnt_sb);
+        struct jffs2_mount_opts *opts = &c->mount_opts;
+
+        if (opts->override_compr)
+                seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
+
+        return 0;
+}
+
 static int jffs2_sync_fs(struct super_block *sb, int wait)
 {
         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
@@ -133,6 +158,71 @@ static const struct export_operations jffs2_export_ops = {
         .fh_to_parent = jffs2_fh_to_parent,
 };
 
+/*
+ * JFFS2 mount options.
+ *
+ * Opt_override_compr: override default compressor
+ * Opt_err: just end of array marker
+ */
+enum {
+        Opt_override_compr,
+        Opt_err,
+};
+
+static const match_table_t tokens = {
+        {Opt_override_compr, "compr=%s"},
+        {Opt_err, NULL},
+};
+
+static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
+{
+        substring_t args[MAX_OPT_ARGS];
+        char *p, *name;
+
+        if (!data)
+                return 0;
+
+        while ((p = strsep(&data, ","))) {
+                int token;
+
+                if (!*p)
+                        continue;
+
+                token = match_token(p, tokens, args);
+                switch (token) {
+                case Opt_override_compr:
+                        name = match_strdup(&args[0]);
+
+                        if (!name)
+                                return -ENOMEM;
+                        if (!strcmp(name, "none")) {
+                                c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
+                                c->mount_opts.override_compr = true;
+                        }
+                        kfree(name);
+                        break;
+                default:
+                        printk(KERN_ERR "JFFS2 Error: unrecognized mount option '%s' or missing value\n",
+                                        p);
+                        return -EINVAL;
+                }
+        }
+
+        return 0;
+}
+
+static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
+{
+        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
+        int err;
+
+        err = jffs2_parse_options(c, data);
+        if (err)
+                return -EINVAL;
+
+        return jffs2_do_remount_fs(sb, flags, data);
+}
+
 static const struct super_operations jffs2_super_operations =
 {
         .alloc_inode =  jffs2_alloc_inode,
@@ -143,6 +233,7 @@ static const struct super_operations jffs2_super_operations =
         .remount_fs =   jffs2_remount_fs,
         .evict_inode =  jffs2_evict_inode,
         .dirty_inode =  jffs2_dirty_inode,
+        .show_options = jffs2_show_options,
         .sync_fs =      jffs2_sync_fs,
 };
 
@@ -166,6 +257,12 @@ static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
         c->os_priv = sb;
         sb->s_fs_info = c;
 
+        ret = jffs2_parse_options(c, data);
+        if (ret) {
+                kfree(c);
+                return -EINVAL;
+        }
+
         /* Initialize JFFS2 superblock locks, the further initialization will
          * be done later */
         mutex_init(&c->alloc_sem);