From 29333920a5a46edcc9b728e2cf0134d5a9b516ee Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 24 Jan 2010 00:04:07 -0500 Subject: 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 --- fs/affs/super.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) (limited to 'fs/affs/super.c') diff --git a/fs/affs/super.c b/fs/affs/super.c index b2a5958..be6a6e8 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(); -- cgit v1.1