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authorEric Sandeen <sandeen@redhat.com>2010-02-15 20:17:55 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-13 13:20:18 -0700
commit670a13a74e34d9fff0cd03df73d8a2b77f7decb7 (patch)
tree09fa8e8a169b32b64c65b15d4d9e8969908a726d
parentc60ca6232164fc6abea21bcf3f58172607f491e5 (diff)
ext4: Fix optional-arg mount options
commit 15121c18a22ae483279f76dc9e554334b800d0f7 upstream. We have 2 mount options, "barrier" and "auto_da_alloc" which may or may not take a 1/0 argument. This causes the ext4 superblock mount code to subtract uninitialized pointers and pass the result to kmalloc, which results in very noisy failures. Per Ted's suggestion, initialize the args struct so that we know whether match_token() found an argument for the option, and skip match_int() if not. Also, return error (0) from parse_options if we thought we found an argument, but match_int() Fails. Reported-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Acked-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--fs/ext4/super.c23
1 files changed, 15 insertions, 8 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e820b936e1d0..f27e045df7a6 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1218,6 +1218,11 @@ static int parse_options(char *options, struct super_block *sb,
if (!*p)
continue;
+ /*
+ * Initialize args struct so we know whether arg was
+ * found; some options take optional arguments.
+ */
+ args[0].to = args[0].from = 0;
token = match_token(p, tokens, args);
switch (token) {
case Opt_bsd_df:
@@ -1503,10 +1508,11 @@ set_qf_format:
clear_opt(sbi->s_mount_opt, BARRIER);
break;
case Opt_barrier:
- if (match_int(&args[0], &option)) {
- set_opt(sbi->s_mount_opt, BARRIER);
- break;
- }
+ if (args[0].from) {
+ if (match_int(&args[0], &option))
+ return 0;
+ } else
+ option = 1; /* No argument, default to 1 */
if (option)
set_opt(sbi->s_mount_opt, BARRIER);
else
@@ -1579,10 +1585,11 @@ set_qf_format:
set_opt(sbi->s_mount_opt,NO_AUTO_DA_ALLOC);
break;
case Opt_auto_da_alloc:
- if (match_int(&args[0], &option)) {
- clear_opt(sbi->s_mount_opt, NO_AUTO_DA_ALLOC);
- break;
- }
+ if (args[0].from) {
+ if (match_int(&args[0], &option))
+ return 0;
+ } else
+ option = 1; /* No argument, default to 1 */
if (option)
clear_opt(sbi->s_mount_opt, NO_AUTO_DA_ALLOC);
else