Merge tag 'for-6.9-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fix race when reading extent buffer and 'uptodate' status is missed
   by one thread (introduced in 6.5)

 - do additional validation of devices using major:minor numbers

 - zoned mode fixes:
     - use zone-aware super block access during scrub
     - fix use-after-free during device replace (found by KASAN)
     - also delete zones that are 100% unusable to reclaim space

 - extent unpinning fixes:
     - fix extent map leak after error handling
     - print correct range in error message

 - error code and message updates

* tag 'for-6.9-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix race in read_extent_buffer_pages()
  btrfs: return accurate error code on open failure in open_fs_devices()
  btrfs: zoned: don't skip block groups with 100% zone unusable
  btrfs: use btrfs_warn() to log message at btrfs_add_extent_mapping()
  btrfs: fix message not properly printing interval when adding extent map
  btrfs: fix warning messages not printing interval at unpin_extent_range()
  btrfs: fix extent map leak in unexpected scenario at unpin_extent_cache()
  btrfs: validate device maj:min during open
  btrfs: zoned: fix use-after-free in do_zone_finish()
  btrfs: zoned: use zone aware sb location for scrub

1 files changed, 13 insertions, 0 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 7441245b1ceb15..61594eaf1f8969 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4333,6 +4333,19 @@ int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
 	if (test_and_set_bit(EXTENT_BUFFER_READING, &eb->bflags))
 		goto done;
 
+	/*
+	 * Between the initial test_bit(EXTENT_BUFFER_UPTODATE) and the above
+	 * test_and_set_bit(EXTENT_BUFFER_READING), someone else could have
+	 * started and finished reading the same eb.  In this case, UPTODATE
+	 * will now be set, and we shouldn't read it in again.
+	 */
+	if (unlikely(test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))) {
+		clear_bit(EXTENT_BUFFER_READING, &eb->bflags);
+		smp_mb__after_atomic();
+		wake_up_bit(&eb->bflags, EXTENT_BUFFER_READING);
+		return 0;
+	}
+
 	clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
 	eb->read_mirror = 0;
 	check_buffer_tree_ref(eb);