btrfs: add a btrfs_inode pointer to struct btrfs_bio

All btrfs_bio I/Os are associated with an inode.  Add a pointer to that
inode, which will allow to simplify a lot of calling conventions, and
which will be needed in the I/O completion path in the future.

This grow the btrfs_bio structure by a pointer, but that grows will
be offset by the removal of the device pointer soon.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/bio.c

@@ -22,9 +22,11 @@ static struct bio_set btrfs_bioset;
  * is already initialized by the block layer.
  */
 static inline void btrfs_bio_init(struct btrfs_bio *bbio,
+				  struct btrfs_inode *inode,
 				  btrfs_bio_end_io_t end_io, void *private)
 {
 	memset(bbio, 0, offsetof(struct btrfs_bio, bio));
+	bbio->inode = inode;
 	bbio->end_io = end_io;
 	bbio->private = private;
 }
@@ -37,16 +39,18 @@ static inline void btrfs_bio_init(struct btrfs_bio *bbio,
  * a mempool.
  */
 struct bio *btrfs_bio_alloc(unsigned int nr_vecs, blk_opf_t opf,
+			    struct btrfs_inode *inode,
 			    btrfs_bio_end_io_t end_io, void *private)
 {
 	struct bio *bio;
 
 	bio = bio_alloc_bioset(NULL, nr_vecs, opf, GFP_NOFS, &btrfs_bioset);
-	btrfs_bio_init(btrfs_bio(bio), end_io, private);
+	btrfs_bio_init(btrfs_bio(bio), inode, end_io, private);
 	return bio;
 }
 
 struct bio *btrfs_bio_clone_partial(struct bio *orig, u64 offset, u64 size,
+				    struct btrfs_inode *inode,
 				    btrfs_bio_end_io_t end_io, void *private)
 {
 	struct bio *bio;
@@ -56,7 +60,7 @@ struct bio *btrfs_bio_clone_partial(struct bio *orig, u64 offset, u64 size,
 
 	bio = bio_alloc_clone(orig->bi_bdev, orig, GFP_NOFS, &btrfs_bioset);
 	bbio = btrfs_bio(bio);
-	btrfs_bio_init(bbio, end_io, private);
+	btrfs_bio_init(bbio, inode, end_io, private);
 
 	bio_trim(bio, offset >> 9, size >> 9);
 	bbio->iter = bio->bi_iter;

fs/btrfs/bio.h

@@ -41,7 +41,8 @@ struct btrfs_bio {
 	unsigned int is_metadata:1;
 	struct bvec_iter iter;
 
-	/* File offset that this I/O operates on. */
+	/* Inode and offset into it that this I/O operates on. */
+	struct btrfs_inode *inode;
 	u64 file_offset;
 
 	/* @device is for stripe IO submission. */
@@ -80,8 +81,10 @@ int __init btrfs_bioset_init(void);
 void __cold btrfs_bioset_exit(void);
 
 struct bio *btrfs_bio_alloc(unsigned int nr_vecs, blk_opf_t opf,
+			    struct btrfs_inode *inode,
 			    btrfs_bio_end_io_t end_io, void *private);
 struct bio *btrfs_bio_clone_partial(struct bio *orig, u64 offset, u64 size,
+				    struct btrfs_inode *inode,
 				    btrfs_bio_end_io_t end_io, void *private);
 
 

fs/btrfs/compression.c

@@ -344,7 +344,8 @@ static struct bio *alloc_compressed_bio(struct compressed_bio *cb, u64 disk_byte
 	struct bio *bio;
 	int ret;
 
-	bio = btrfs_bio_alloc(BIO_MAX_VECS, opf, endio_func, cb);
+	bio = btrfs_bio_alloc(BIO_MAX_VECS, opf, BTRFS_I(cb->inode), endio_func,
+			      cb);
 	bio->bi_iter.bi_sector = disk_bytenr >> SECTOR_SHIFT;
 
 	em = btrfs_get_chunk_map(fs_info, disk_bytenr, fs_info->sectorsize);

fs/btrfs/extent_io.c

@@ -740,7 +740,8 @@ int btrfs_repair_one_sector(struct btrfs_inode *inode, struct btrfs_bio *failed_
 		return -EIO;
 	}
 
-	repair_bio = btrfs_bio_alloc(1, REQ_OP_READ, failed_bbio->end_io,
+	repair_bio = btrfs_bio_alloc(1, REQ_OP_READ, failed_bbio->inode,
+				     failed_bbio->end_io,
 				     failed_bbio->private);
 	repair_bbio = btrfs_bio(repair_bio);
 	repair_bbio->file_offset = start;
@@ -1394,9 +1395,8 @@ static int alloc_new_bio(struct btrfs_inode *inode,
 	struct bio *bio;
 	int ret;
 
-	ASSERT(bio_ctrl->end_io_func);
-
-	bio = btrfs_bio_alloc(BIO_MAX_VECS, opf, bio_ctrl->end_io_func, NULL);
+	bio = btrfs_bio_alloc(BIO_MAX_VECS, opf, inode, bio_ctrl->end_io_func,
+			      NULL);
 	/*
 	 * For compressed page range, its disk_bytenr is always @disk_bytenr
 	 * passed in, no matter if we have added any range into previous bio.

fs/btrfs/inode.c

@@ -8097,7 +8097,8 @@ static void btrfs_submit_direct(const struct iomap_iter *iter,
 		 * the allocation is backed by btrfs_bioset.
 		 */
 		bio = btrfs_bio_clone_partial(dio_bio, clone_offset, clone_len,
-					      btrfs_end_dio_bio, dip);
+					      BTRFS_I(inode), btrfs_end_dio_bio,
+					      dip);
 		btrfs_bio(bio)->file_offset = file_offset;
 
 		if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
@@ -10409,6 +10410,7 @@ int btrfs_encoded_read_regular_fill_pages(struct btrfs_inode *inode,
 
 			if (!bio) {
 				bio = btrfs_bio_alloc(BIO_MAX_VECS, REQ_OP_READ,
+						      inode,
 						      btrfs_encoded_read_endio,
 						      &priv);
 				bio->bi_iter.bi_sector =