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