[PATCH] ext2: fix mount options parting

Restore old set of ext2 mount options when remounting of a filesystem
fails.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 30 insertions, 3 deletions

diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index eed521d22cf0..e977f8566d14 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -2,6 +2,15 @@
 #include <linux/ext2_fs.h>
 
 /*
+ * ext2 mount options
+ */
+struct ext2_mount_options {
+        unsigned long s_mount_opt;
+        uid_t s_resuid;
+        gid_t s_resgid;
+};
+
+/*
  * second extended file system inode data in memory
  */
 struct ext2_inode_info {
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 876e391f2871..dcfe331dc4c4 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -936,12 +936,23 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
         struct ext2_sb_info * sbi = EXT2_SB(sb);
         struct ext2_super_block * es;
         unsigned long old_mount_opt = sbi->s_mount_opt;
+        struct ext2_mount_options old_opts;
+        unsigned long old_sb_flags;
+        int err;
+
+        /* Store the old options */
+        old_sb_flags = sb->s_flags;
+        old_opts.s_mount_opt = sbi->s_mount_opt;
+        old_opts.s_resuid = sbi->s_resuid;
+        old_opts.s_resgid = sbi->s_resgid;
 
         /*
          * Allow the "check" option to be passed as a remount option.
          */
-        if (!parse_options (data, sbi))
-                return -EINVAL;
+        if (!parse_options (data, sbi)) {
+                err = -EINVAL;
+                goto restore_opts;
+        }
 
         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
@@ -971,7 +982,8 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
                                "unsupported optional features (%x).\n",
                                sb->s_id, le32_to_cpu(ret));
-                        return -EROFS;
+                        err = -EROFS;
+                        goto restore_opts;
                 }
                 /*
                  * Mounting a RDONLY partition read-write, so reread and
@@ -984,6 +996,12 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
         }
         ext2_sync_super(sb, es);
         return 0;
+restore_opts:
+        sbi->s_mount_opt = old_opts.s_mount_opt;
+        sbi->s_resuid = old_opts.s_resuid;
+        sbi->s_resgid = old_opts.s_resgid;
+        sb->s_flags = old_sb_flags;
+        return err;
 }
 
 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)