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, 3 insertions, 1 deletions

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 5b9408e3b370..ac7f067b7bdd 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -488,7 +488,6 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	jbd2_journal_wait_updates(journal);
 
 	commit_transaction->t_state = T_SWITCH;
-	write_unlock(&journal->j_state_lock);
 
 	J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
 			journal->j_max_transaction_buffers);
@@ -508,6 +507,8 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	 * has reserved.  This is consistent with the existing behaviour
 	 * that multiple jbd2_journal_get_write_access() calls to the same
 	 * buffer are perfectly permissible.
+	 * We use journal->j_state_lock here to serialize processing of
+	 * t_reserved_list with eviction of buffers from journal_unmap_buffer().
 	 */
 	while (commit_transaction->t_reserved_list) {
 		jh = commit_transaction->t_reserved_list;
@@ -527,6 +528,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 		jbd2_journal_refile_buffer(journal, jh);
 	}
 
+	write_unlock(&journal->j_state_lock);
 	/*
 	 * Now try to drop any written-back buffers from the journal's
 	 * checkpoint lists.  We do this *before* commit because it potentially