Btrfs: fix error path when failing to submit bio for direct IO write

Commit 61de718fceb6 ("Btrfs: fix memory corruption on failure to submit
bio for direct IO") fixed problems with the error handling code after we
fail to submit a bio for direct IO. However there were 2 problems that it
did not address when the failure is due to memory allocation failures for
direct IO writes:

1) We considered that there could be only one ordered extent for the whole
   IO range, which is not always true, as we can have multiple;

2) It did not set the bit BTRFS_ORDERED_IO_DONE in the ordered extent,
   which can make other tasks running btrfs_wait_logged_extents() hang
   forever, since they wait for that bit to be set. The general assumption
   is that regardless of an error, the BTRFS_ORDERED_IO_DONE is always set
   and it precedes setting the bit BTRFS_ORDERED_COMPLETE.

Fix these issues by moving part of the btrfs_endio_direct_write() handler
into a new helper function and having that new helper function called when
we fail to allocate memory to submit the bio (and its private object) for
a direct IO write.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f82d1f4460ddc0cc130e31ee59fc02cf72118518..66106b48b478654a0bf8dbbe454b2c1a79260a47 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7995,22 +7995,22 @@ static void btrfs_endio_direct_read(struct bio *bio)
        bio_put(bio);
 }
 
-static void btrfs_endio_direct_write(struct bio *bio)
+static void btrfs_endio_direct_write_update_ordered(struct inode *inode,
+                                                   const u64 offset,
+                                                   const u64 bytes,
+                                                   const int uptodate)
 {
-       struct btrfs_dio_private *dip = bio->bi_private;
-       struct inode *inode = dip->inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
        struct btrfs_ordered_extent *ordered = NULL;
-       u64 ordered_offset = dip->logical_offset;
-       u64 ordered_bytes = dip->bytes;
-       struct bio *dio_bio;
+       u64 ordered_offset = offset;
+       u64 ordered_bytes = bytes;
        int ret;
 
 again:
        ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
                                                   &ordered_offset,
                                                   ordered_bytes,
-                                                  !bio->bi_error);
+                                                  uptodate);
        if (!ret)
                goto out_test;
 
@@ -8023,13 +8023,22 @@ out_test:
         * our bio might span multiple ordered extents.  If we haven't
         * completed the accounting for the whole dio, go back and try again
         */
-       if (ordered_offset < dip->logical_offset + dip->bytes) {
-               ordered_bytes = dip->logical_offset + dip->bytes -
-                       ordered_offset;
+       if (ordered_offset < offset + bytes) {
+               ordered_bytes = offset + bytes - ordered_offset;
                ordered = NULL;
                goto again;
        }
-       dio_bio = dip->dio_bio;
+}
+
+static void btrfs_endio_direct_write(struct bio *bio)
+{
+       struct btrfs_dio_private *dip = bio->bi_private;
+       struct bio *dio_bio = dip->dio_bio;
+
+       btrfs_endio_direct_write_update_ordered(dip->inode,
+                                               dip->logical_offset,
+                                               dip->bytes,
+                                               !bio->bi_error);
 
        kfree(dip);
 
@@ -8365,24 +8374,15 @@ free_ordered:
                dip = NULL;
                io_bio = NULL;
        } else {
-               if (write) {
-                       struct btrfs_ordered_extent *ordered;
-
-                       ordered = btrfs_lookup_ordered_extent(inode,
-                                                             file_offset);
-                       set_bit(BTRFS_ORDERED_IOERR, &ordered->flags);
-                       /*
-                        * Decrements our ref on the ordered extent and removes
-                        * the ordered extent from the inode's ordered tree,
-                        * doing all the proper resource cleanup such as for the
-                        * reserved space and waking up any waiters for this
-                        * ordered extent (through btrfs_remove_ordered_extent).
-                        */
-                       btrfs_finish_ordered_io(ordered);
-               } else {
+               if (write)
+                       btrfs_endio_direct_write_update_ordered(inode,
+                                               file_offset,
+                                               dio_bio->bi_iter.bi_size,
+                                               0);
+               else
                        unlock_extent(&BTRFS_I(inode)->io_tree, file_offset,
                              file_offset + dio_bio->bi_iter.bi_size - 1);
-               }
+
                dio_bio->bi_error = -EIO;
                /*
                 * Releases and cleans up our dio_bio, no need to bio_put()