From 4246a0b63bd8f56a1469b12eafeb875b1041a451 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 20 Jul 2015 15:29:37 +0200 Subject: block: add a bi_error field to struct bio Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Reviewed-by: NeilBrown Signed-off-by: Jens Axboe --- fs/btrfs/extent_io.c | 30 ++++++++++++------------------ 1 file changed, 12 insertions(+), 18 deletions(-) (limited to 'fs/btrfs/extent_io.c') diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 02d0581..c22f175 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -2486,7 +2486,7 @@ int end_extent_writepage(struct page *page, int err, u64 start, u64 end) * Scheduling is not allowed, so the extent state tree is expected * to have one and only one object corresponding to this IO. */ -static void end_bio_extent_writepage(struct bio *bio, int err) +static void end_bio_extent_writepage(struct bio *bio) { struct bio_vec *bvec; u64 start; @@ -2516,7 +2516,7 @@ static void end_bio_extent_writepage(struct bio *bio, int err) start = page_offset(page); end = start + bvec->bv_offset + bvec->bv_len - 1; - if (end_extent_writepage(page, err, start, end)) + if (end_extent_writepage(page, bio->bi_error, start, end)) continue; end_page_writeback(page); @@ -2548,10 +2548,10 @@ endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len, * Scheduling is not allowed, so the extent state tree is expected * to have one and only one object corresponding to this IO. */ -static void end_bio_extent_readpage(struct bio *bio, int err) +static void end_bio_extent_readpage(struct bio *bio) { struct bio_vec *bvec; - int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); + int uptodate = !bio->bi_error; struct btrfs_io_bio *io_bio = btrfs_io_bio(bio); struct extent_io_tree *tree; u64 offset = 0; @@ -2564,16 +2564,13 @@ static void end_bio_extent_readpage(struct bio *bio, int err) int ret; int i; - if (err) - uptodate = 0; - bio_for_each_segment_all(bvec, bio, i) { struct page *page = bvec->bv_page; struct inode *inode = page->mapping->host; pr_debug("end_bio_extent_readpage: bi_sector=%llu, err=%d, " - "mirror=%u\n", (u64)bio->bi_iter.bi_sector, err, - io_bio->mirror_num); + "mirror=%u\n", (u64)bio->bi_iter.bi_sector, + bio->bi_error, io_bio->mirror_num); tree = &BTRFS_I(inode)->io_tree; /* We always issue full-page reads, but if some block @@ -2614,8 +2611,7 @@ static void end_bio_extent_readpage(struct bio *bio, int err) if (tree->ops && tree->ops->readpage_io_failed_hook) { ret = tree->ops->readpage_io_failed_hook(page, mirror); - if (!ret && !err && - test_bit(BIO_UPTODATE, &bio->bi_flags)) + if (!ret && !bio->bi_error) uptodate = 1; } else { /* @@ -2631,10 +2627,7 @@ static void end_bio_extent_readpage(struct bio *bio, int err) ret = bio_readpage_error(bio, offset, page, start, end, mirror); if (ret == 0) { - uptodate = - test_bit(BIO_UPTODATE, &bio->bi_flags); - if (err) - uptodate = 0; + uptodate = !bio->bi_error; offset += len; continue; } @@ -2684,7 +2677,7 @@ readpage_ok: endio_readpage_release_extent(tree, extent_start, extent_len, uptodate); if (io_bio->end_io) - io_bio->end_io(io_bio, err); + io_bio->end_io(io_bio, bio->bi_error); bio_put(bio); } @@ -3696,7 +3689,7 @@ static void set_btree_ioerr(struct page *page) } } -static void end_bio_extent_buffer_writepage(struct bio *bio, int err) +static void end_bio_extent_buffer_writepage(struct bio *bio) { struct bio_vec *bvec; struct extent_buffer *eb; @@ -3709,7 +3702,8 @@ static void end_bio_extent_buffer_writepage(struct bio *bio, int err) BUG_ON(!eb); done = atomic_dec_and_test(&eb->io_pages); - if (err || test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) { + if (bio->bi_error || + test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) { ClearPageUptodate(page); set_btree_ioerr(page); } -- cgit v1.1