Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 fixes from Ted Ts'o:
 "Fix some syzbot-detected bugs, as well as other bugs found by I/O
  injection testing.

  Change ext4's fallocate to consistently drop set[ug]id bits when an
  fallocate operation might possibly change the user-visible contents of
  a file.

  Also, improve handling of potentially invalid values in the the
  s_overhead_cluster superblock field to avoid ext4 returning a negative
  number of free blocks"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  jbd2: fix a potential race while discarding reserved buffers after an abort
  ext4: update the cached overhead value in the superblock
  ext4: force overhead calculation if the s_overhead_cluster makes no sense
  ext4: fix overhead calculation to account for the reserved gdt blocks
  ext4, doc: fix incorrect h_reserved size
  ext4: limit length to bitmap_maxbytes - blocksize in punch_hole
  ext4: fix use-after-free in ext4_search_dir
  ext4: fix bug_on in start_this_handle during umount filesystem
  ext4: fix symlink file size not match to file content
  ext4: fix fallocate to use file_modified to update permissions consistently

1 files changed, 29 insertions, 11 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 81749eaddf4c..1466fbdbc8e3 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1199,20 +1199,25 @@ static void ext4_put_super(struct super_block *sb)
 	int aborted = 0;
 	int i, err;
 
-	ext4_unregister_li_request(sb);
-	ext4_quota_off_umount(sb);
-
-	flush_work(&sbi->s_error_work);
-	destroy_workqueue(sbi->rsv_conversion_wq);
-	ext4_release_orphan_info(sb);
-
 	/*
 	 * Unregister sysfs before destroying jbd2 journal.
 	 * Since we could still access attr_journal_task attribute via sysfs
 	 * path which could have sbi->s_journal->j_task as NULL
+	 * Unregister sysfs before flush sbi->s_error_work.
+	 * Since user may read /proc/fs/ext4/xx/mb_groups during umount, If
+	 * read metadata verify failed then will queue error work.
+	 * flush_stashed_error_work will call start_this_handle may trigger
+	 * BUG_ON.
 	 */
 	ext4_unregister_sysfs(sb);
 
+	ext4_unregister_li_request(sb);
+	ext4_quota_off_umount(sb);
+
+	flush_work(&sbi->s_error_work);
+	destroy_workqueue(sbi->rsv_conversion_wq);
+	ext4_release_orphan_info(sb);
+
 	if (sbi->s_journal) {
 		aborted = is_journal_aborted(sbi->s_journal);
 		err = jbd2_journal_destroy(sbi->s_journal);
@@ -4172,9 +4177,11 @@ static int count_overhead(struct super_block *sb, ext4_group_t grp,
 	ext4_fsblk_t		first_block, last_block, b;
 	ext4_group_t		i, ngroups = ext4_get_groups_count(sb);
 	int			s, j, count = 0;
+	int			has_super = ext4_bg_has_super(sb, grp);
 
 	if (!ext4_has_feature_bigalloc(sb))
-		return (ext4_bg_has_super(sb, grp) + ext4_bg_num_gdb(sb, grp) +
+		return (has_super + ext4_bg_num_gdb(sb, grp) +
+			(has_super ? le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0) +
 			sbi->s_itb_per_group + 2);
 
 	first_block = le32_to_cpu(sbi->s_es->s_first_data_block) +
@@ -5282,9 +5289,18 @@ no_journal:
 	 * Get the # of file system overhead blocks from the
 	 * superblock if present.
 	 */
-	if (es->s_overhead_clusters)
-		sbi->s_overhead = le32_to_cpu(es->s_overhead_clusters);
-	else {
+	sbi->s_overhead = le32_to_cpu(es->s_overhead_clusters);
+	/* ignore the precalculated value if it is ridiculous */
+	if (sbi->s_overhead > ext4_blocks_count(es))
+		sbi->s_overhead = 0;
+	/*
+	 * If the bigalloc feature is not enabled recalculating the
+	 * overhead doesn't take long, so we might as well just redo
+	 * it to make sure we are using the correct value.
+	 */
+	if (!ext4_has_feature_bigalloc(sb))
+		sbi->s_overhead = 0;
+	if (sbi->s_overhead == 0) {
 		err = ext4_calculate_overhead(sb);
 		if (err)
 			goto failed_mount_wq;
@@ -5602,6 +5618,8 @@ static int ext4_fill_super(struct super_block *sb, struct fs_context *fc)
 		ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
 			 "Quota mode: %s.", descr, ext4_quota_mode(sb));
 
+	/* Update the s_overhead_clusters if necessary */
+	ext4_update_overhead(sb);
 	return 0;
 
 free_sbi: