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[1/3] btrfs: document mandatory order of bio in btrfs_io_bio

Message ID e9e6988cba06239527f8a4a33c62e7a21b0f9762.1497281195.git.dsterba@suse.com (mailing list archive)
State New, archived
Headers show

Commit Message

David Sterba June 12, 2017, 3:29 p.m. UTC
Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/volumes.h | 4 ++++
 1 file changed, 4 insertions(+)
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Patch

diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 58b97b6f5f02..35327efecdbb 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -281,6 +281,10 @@  struct btrfs_io_bio {
 	u8 *csum_allocated;
 	btrfs_io_bio_end_io_t *end_io;
 	struct bvec_iter iter;
+	/*
+	 * This member must come last, bio_alloc_bioset will allocate enough
+	 * bytes for entire btrfs_io_bio but relies on bio being last.
+	 */
 	struct bio bio;
 };