@@ -870,6 +870,9 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
/* include any pages we added in add_ra-bio_pages */
cb->len = bio->bi_iter.bi_size;
+ /* Save bi_iter so that end_bio_extent_readpage() won't freak out. */
+ btrfs_bio_save_iter(btrfs_bio(bio));
+
while (cur_disk_byte < disk_bytenr + compressed_len) {
u64 offset = cur_disk_byte - disk_bytenr;
unsigned int index = offset >> PAGE_SHIFT;
@@ -817,6 +817,7 @@ static void run_one_async_done(struct btrfs_work *work)
/* If an error occurred we just want to clean up the bio and move on */
if (async->status) {
async->bio->bi_status = async->status;
+ btrfs_bio_save_iter(btrfs_bio(async->bio));
bio_endio(async->bio);
return;
}
@@ -949,6 +950,7 @@ blk_status_t btrfs_submit_metadata_bio(struct inode *inode, struct bio *bio,
out_w_error:
bio->bi_status = ret;
+ btrfs_bio_save_iter(btrfs_bio(bio));
bio_endio(bio);
return ret;
}
@@ -175,6 +175,11 @@ int __must_check submit_one_bio(struct bio *bio, int mirror_num,
/* Caller should ensure the bio has at least some range added */
ASSERT(bio->bi_iter.bi_size);
+ /*
+ * This for later endio on errors, as later endio functions will rely
+ * on btrfs_bio::iter.
+ */
+ btrfs_bio_save_iter(btrfs_bio(bio));
if (is_data_inode(tree->private_data))
ret = btrfs_submit_data_bio(tree->private_data, bio, mirror_num,
bio_flags);
@@ -192,6 +197,7 @@ static void end_write_bio(struct extent_page_data *epd, int ret)
if (bio) {
bio->bi_status = errno_to_blk_status(ret);
+ btrfs_bio_save_iter(btrfs_bio(bio));
bio_endio(bio);
epd->bio_ctrl.bio = NULL;
}
@@ -3355,6 +3361,7 @@ static int alloc_new_bio(struct btrfs_inode *inode,
error:
bio_ctrl->bio = NULL;
bio->bi_status = errno_to_blk_status(ret);
+ btrfs_bio_save_iter(btrfs_bio(bio));
bio_endio(bio);
return ret;
}
@@ -1731,6 +1731,7 @@ int raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc,
return PTR_ERR(rbio);
}
bio_list_add(&rbio->bio_list, bio);
+ btrfs_bio_save_iter(btrfs_bio(bio));
rbio->bio_list_bytes = bio->bi_iter.bi_size;
rbio->operation = BTRFS_RBIO_WRITE;
@@ -2135,6 +2136,7 @@ int raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
rbio->operation = BTRFS_RBIO_READ_REBUILD;
bio_list_add(&rbio->bio_list, bio);
+ btrfs_bio_save_iter(btrfs_bio(bio));
rbio->bio_list_bytes = bio->bi_iter.bi_size;
rbio->faila = find_logical_bio_stripe(rbio, bio);
@@ -6794,6 +6794,7 @@ blk_status_t btrfs_map_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
map_length = length;
btrfs_bio_counter_inc_blocked(fs_info);
+ btrfs_bio_save_iter(btrfs_bio(bio));
ret = __btrfs_map_block(fs_info, btrfs_op(bio), logical,
&map_length, &bioc, mirror_num, 1);
if (ret) {
@@ -334,6 +334,12 @@ struct btrfs_bio {
struct btrfs_device *device;
u8 *csum;
u8 csum_inline[BTRFS_BIO_INLINE_CSUM_SIZE];
+ /*
+ * Saved bio::bi_iter before submission.
+ *
+ * This allows us to interate the cloned/split bio properly, as at
+ * endio time bio::bi_iter is no longer reliable.
+ */
struct bvec_iter iter;
/*
@@ -356,6 +362,17 @@ static inline void btrfs_bio_free_csum(struct btrfs_bio *bbio)
}
}
+/*
+ * To save bbio::bio->bi_iter into bbio::iter so for callers who need the
+ * original bi_iter can access the original part of the bio.
+ * This is especially important for the incoming split btrfs_bio, which needs
+ * to call its endio for and only for the split range.
+ */
+static inline void btrfs_bio_save_iter(struct btrfs_bio *bbio)
+{
+ bbio->iter = bbio->bio.bi_iter;
+}
+
struct btrfs_io_stripe {
struct btrfs_device *dev;
u64 physical;
Currently btrfs_bio::iter is only utilized by direct IO. But later we will utilize btrfs_bio::iter to record the original bi_iter, for all endio functions to iterate the original range. Thus this patch will introduce a new helper, btrfs_bio_save_iter(), to save bi_iter into btrfs_bio::iter. All path that can lead to an bio_endio() call needs such btrfs_bio_save_iter() call. Under most common case, there will be a btrfs_map_bio() call to handle submitted bios. While for other error out paths, we need to call btrfs_bio_save_iter() manually, or later endio functions will ASSERT() on empty btrfs_bio::iter. Signed-off-by: Qu Wenruo <wqu@suse.com> --- fs/btrfs/compression.c | 3 +++ fs/btrfs/disk-io.c | 2 ++ fs/btrfs/extent_io.c | 7 +++++++ fs/btrfs/raid56.c | 2 ++ fs/btrfs/volumes.c | 1 + fs/btrfs/volumes.h | 17 +++++++++++++++++ 6 files changed, 32 insertions(+)