diff options
| author | Al Viro <viro@zeniv.linux.org.uk> | 2010-01-24 00:04:07 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2010-01-26 22:22:24 -0500 |
| commit | 29333920a5a46edcc9b728e2cf0134d5a9b516ee (patch) | |
| tree | 2991b9f6d82d43c712278d6364da4faad4a0180d /fs/affs/super.c | |
| parent | afc70ed05a07bfe171f7a5b8fdc80bdb073d314f (diff) | |
| download | lwn-29333920a5a46edcc9b728e2cf0134d5a9b516ee.tar.gz lwn-29333920a5a46edcc9b728e2cf0134d5a9b516ee.zip | |
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.c | 17 |
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(); |