GFS2: Fix use-after-free bug on umount

There was a use-after-free with the GFS2 super block during
umount. This patch moves almost all of the umount code from
->put_super into ->kill_sb, the only bit that cannot be moved
being the glock hash clearing which has to remain as ->put_super
due to umount ordering requirements. As a result its now obvious
that the kfree is the final operation, whereas before it was
hidden in ->put_super.

Also gfs2_jindex_free is then only referenced from a single file
so thats moved and marked static too.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This commit is contained in:
Steven Whitehouse
2008-11-27 08:27:28 +00:00
والد 2e204703a1
کامیت 3af165ac4d
6فایلهای تغییر یافته به همراه94 افزوده شده و 114 حذف شده

مشاهده پرونده

@@ -95,7 +95,7 @@ do_flush:
* Returns: errno
*/
static int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
{
struct gfs2_holder t_gh;
int error;
@@ -121,70 +121,6 @@ static int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
return error;
}
/**
* gfs2_put_super - Unmount the filesystem
* @sb: The VFS superblock
*
*/
static void gfs2_put_super(struct super_block *sb)
{
struct gfs2_sbd *sdp = sb->s_fs_info;
int error;
/* Unfreeze the filesystem, if we need to */
mutex_lock(&sdp->sd_freeze_lock);
if (sdp->sd_freeze_count)
gfs2_glock_dq_uninit(&sdp->sd_freeze_gh);
mutex_unlock(&sdp->sd_freeze_lock);
kthread_stop(sdp->sd_quotad_process);
kthread_stop(sdp->sd_logd_process);
kthread_stop(sdp->sd_recoverd_process);
if (!(sb->s_flags & MS_RDONLY)) {
error = gfs2_make_fs_ro(sdp);
if (error)
gfs2_io_error(sdp);
}
/* At this point, we're through modifying the disk */
/* Release stuff */
iput(sdp->sd_jindex);
iput(sdp->sd_inum_inode);
iput(sdp->sd_statfs_inode);
iput(sdp->sd_rindex);
iput(sdp->sd_quota_inode);
gfs2_glock_put(sdp->sd_rename_gl);
gfs2_glock_put(sdp->sd_trans_gl);
if (!sdp->sd_args.ar_spectator) {
gfs2_glock_dq_uninit(&sdp->sd_journal_gh);
gfs2_glock_dq_uninit(&sdp->sd_jinode_gh);
gfs2_glock_dq_uninit(&sdp->sd_ir_gh);
gfs2_glock_dq_uninit(&sdp->sd_sc_gh);
gfs2_glock_dq_uninit(&sdp->sd_qc_gh);
iput(sdp->sd_ir_inode);
iput(sdp->sd_sc_inode);
iput(sdp->sd_qc_inode);
}
gfs2_glock_dq_uninit(&sdp->sd_live_gh);
gfs2_clear_rgrpd(sdp);
gfs2_jindex_free(sdp);
/* Take apart glock structures and buffer lists */
gfs2_gl_hash_clear(sdp);
/* Unmount the locking protocol */
gfs2_lm_unmount(sdp);
/* At this point, we're through participating in the lockspace */
gfs2_sys_fs_del(sdp);
kfree(sdp);
}
/**
* gfs2_write_super
* @sb: the superblock
@@ -686,7 +622,7 @@ const struct super_operations gfs2_super_ops = {
.destroy_inode = gfs2_destroy_inode,
.write_inode = gfs2_write_inode,
.delete_inode = gfs2_delete_inode,
.put_super = gfs2_put_super,
.put_super = gfs2_gl_hash_clear,
.write_super = gfs2_write_super,
.sync_fs = gfs2_sync_fs,
.write_super_lockfs = gfs2_write_super_lockfs,