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[v4,08/10] btrfs: add extra error messages for delalloc range related errors

Message ID 0e74b8be42025c25f2425d3eda0cda4bf7cebde6.1736591758.git.wqu@suse.com (mailing list archive)
State New, archived
Headers show
Series btrfs: error handling fixes | expand

Commit Message

Qu Wenruo Jan. 11, 2025, 10:43 a.m. UTC
All the error handling bugs I hit so far are all -ENOSPC from either:

- cow_file_range()
- run_delalloc_nocow()
- submit_uncompressed_range()

Previously when those functions failed, there is no error message at
all, making the debugging much harder.

So here we introduce extra error messages for:

- cow_file_range()
- run_delalloc_nocow()
- submit_uncompressed_range()
- writepage_delalloc() when btrfs_run_delalloc_range() failed
- extent_writepage() when extent_writepage_io() failed

One example of the new debug error messages is the following one:

 run fstests generic/750 at 2024-12-08 12:41:41
 BTRFS: device fsid 461b25f5-e240-4543-8deb-e7c2bd01a6d3 devid 1 transid 8 /dev/mapper/test-scratch1 (253:4) scanned by mount (2436600)
 BTRFS info (device dm-4): first mount of filesystem 461b25f5-e240-4543-8deb-e7c2bd01a6d3
 BTRFS info (device dm-4): using crc32c (crc32c-arm64) checksum algorithm
 BTRFS info (device dm-4): forcing free space tree for sector size 4096 with page size 65536
 BTRFS info (device dm-4): using free-space-tree
 BTRFS warning (device dm-4): read-write for sector size 4096 with page size 65536 is experimental
 BTRFS info (device dm-4): checking UUID tree
 BTRFS error (device dm-4): cow_file_range failed, root=363 inode=412 start=503808 len=98304: -28
 BTRFS error (device dm-4): run_delalloc_nocow failed, root=363 inode=412 start=503808 len=98304: -28
 BTRFS error (device dm-4): failed to run delalloc range, root=363 ino=412 folio=458752 submit_bitmap=11-15 start=503808 len=98304: -28

Which shows an error from cow_file_range() which is called inside a
nocow write attempt, along with the extra bitmap from
writepage_delalloc().

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/extent_io.c | 16 ++++++++++++++++
 fs/btrfs/inode.c     | 12 ++++++++++++
 2 files changed, 28 insertions(+)
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Patch

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index f50e4fccd909..72342663341c 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1255,6 +1255,15 @@  static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
 						       wbc);
 			if (ret >= 0)
 				last_finished_delalloc_end = found_start + found_len;
+			if (unlikely(ret < 0))
+				btrfs_err_rl(fs_info,
+"failed to run delalloc range, root=%lld ino=%llu folio=%llu submit_bitmap=%*pbl start=%llu len=%u: %d",
+					     btrfs_root_id(inode->root),
+					     btrfs_ino(inode),
+					     folio_pos(folio),
+					     fs_info->sectors_per_page,
+					     &bio_ctrl->submit_bitmap,
+					     found_start, found_len, ret);
 		} else {
 			/*
 			 * We've hit an error during previous delalloc range,
@@ -1553,6 +1562,13 @@  static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl
 				  PAGE_SIZE, bio_ctrl, i_size);
 	if (ret == 1)
 		return 0;
+	if (ret < 0)
+		btrfs_err_rl(fs_info,
+"failed to submit blocks, root=%lld inode=%llu folio=%llu submit_bitmap=%*pbl: %d",
+			     btrfs_root_id(inode->root),
+			     btrfs_ino(inode),
+			     folio_pos(folio), fs_info->sectors_per_page,
+			     &bio_ctrl->submit_bitmap, ret);
 
 	bio_ctrl->wbc->nr_to_write--;
 
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 73a6b88c6511..3409f1e02de0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1133,6 +1133,10 @@  static void submit_uncompressed_range(struct btrfs_inode *inode,
 		if (locked_folio)
 			btrfs_folio_end_lock(inode->root->fs_info, locked_folio,
 					     start, async_extent->ram_size);
+		btrfs_err_rl(inode->root->fs_info,
+		"%s failed, root=%llu inode=%llu start=%llu len=%llu: %d",
+			     __func__, btrfs_root_id(inode->root),
+			     btrfs_ino(inode), start, async_extent->ram_size, ret);
 	}
 }
 
@@ -1579,6 +1583,10 @@  static noinline int cow_file_range(struct btrfs_inode *inode,
 		btrfs_qgroup_free_data(inode, NULL, start + cur_alloc_size,
 				       end - start - cur_alloc_size + 1, NULL);
 	}
+	btrfs_err_rl(fs_info,
+		     "%s failed, root=%llu inode=%llu start=%llu len=%llu: %d",
+		     __func__, btrfs_root_id(inode->root),
+		     btrfs_ino(inode), orig_start, end + 1 - orig_start, ret);
 	return ret;
 }
 
@@ -2326,6 +2334,10 @@  static noinline int run_delalloc_nocow(struct btrfs_inode *inode,
 		btrfs_qgroup_free_data(inode, NULL, cur_offset, end - cur_offset + 1, NULL);
 	}
 	btrfs_free_path(path);
+	btrfs_err_rl(fs_info,
+		     "%s failed, root=%llu inode=%llu start=%llu len=%llu: %d",
+		     __func__, btrfs_root_id(inode->root),
+		     btrfs_ino(inode), start, end + 1 - start, ret);
 	return ret;
 }