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authorAl Viro <viro@zeniv.linux.org.uk>2010-01-24 08:04:07 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2010-01-27 06:22:24 +0300
commit29333920a5a46edcc9b728e2cf0134d5a9b516ee (patch)
tree2991b9f6d82d43c712278d6364da4faad4a0180d /fs/affs/super.c
parentafc70ed05a07bfe171f7a5b8fdc80bdb073d314f (diff)
downloadlinux-29333920a5a46edcc9b728e2cf0134d5a9b516ee.tar.xz
Fix remount races with symlink handling in affs
A couple of fields in affs_sb_info is used in follow_link() and symlink() for handling AFFS "absolute" symlinks. Need locking against affs_remount() updates. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/affs/super.c')
-rw-r--r--fs/affs/super.c17
1 files changed, 14 insertions, 3 deletions
diff --git a/fs/affs/super.c b/fs/affs/super.c
index b2a5958c6191..be6a6e8ed7d6 100644
--- a/fs/affs/super.c
+++ b/fs/affs/super.c
@@ -221,8 +221,6 @@ parse_options(char *options, uid_t *uid, gid_t *gid, int *mode, int *reserved, s
*mount_opts |= SF_MUFS;
break;
case Opt_prefix:
- /* Free any previous prefix */
- kfree(*prefix);
*prefix = match_strdup(&args[0]);
if (!*prefix)
return 0;
@@ -311,6 +309,7 @@ static int affs_fill_super(struct super_block *sb, void *data, int silent)
return -ENOMEM;
sb->s_fs_info = sbi;
mutex_init(&sbi->s_bmlock);
+ spin_lock_init(&sbi->symlink_lock);
if (!parse_options(data,&uid,&gid,&i,&reserved,&root_block,
&blocksize,&sbi->s_prefix,
@@ -518,14 +517,18 @@ affs_remount(struct super_block *sb, int *flags, char *data)
unsigned long mount_flags;
int res = 0;
char *new_opts = kstrdup(data, GFP_KERNEL);
+ char volume[32];
+ char *prefix = NULL;
pr_debug("AFFS: remount(flags=0x%x,opts=\"%s\")\n",*flags,data);
*flags |= MS_NODIRATIME;
+ memcpy(volume, sbi->s_volume, 32);
if (!parse_options(data, &uid, &gid, &mode, &reserved, &root_block,
- &blocksize, &sbi->s_prefix, sbi->s_volume,
+ &blocksize, &prefix, volume,
&mount_flags)) {
+ kfree(prefix);
kfree(new_opts);
return -EINVAL;
}
@@ -536,6 +539,14 @@ affs_remount(struct super_block *sb, int *flags, char *data)
sbi->s_mode = mode;
sbi->s_uid = uid;
sbi->s_gid = gid;
+ /* protect against readers */
+ spin_lock(&sbi->symlink_lock);
+ if (prefix) {
+ kfree(sbi->s_prefix);
+ sbi->s_prefix = prefix;
+ }
+ memcpy(sbi->s_volume, volume, 32);
+ spin_unlock(&sbi->symlink_lock);
if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
unlock_kernel();