@@ -221,6 +221,44 @@ static bool dec_and_test_compressed_bio(struct compressed_bio *cb,
return last_bio && last_io;
}
+static void finish_compressed_bio_read(struct compressed_bio *cb,
+ struct bio *bio)
+{
+ unsigned int index;
+ struct page *page;
+
+ /* release the compressed pages */
+ for (index = 0; index < cb->nr_pages; index++) {
+ page = cb->compressed_pages[index];
+ page->mapping = NULL;
+ put_page(page);
+ }
+
+ /* do io completion on the original bio */
+ if (cb->errors) {
+ bio_io_error(cb->orig_bio);
+ } else {
+ struct bio_vec *bvec;
+ struct bvec_iter_all iter_all;
+
+ ASSERT(bio);
+ ASSERT(!bio->bi_status);
+ /*
+ * we have verified the checksum already, set page
+ * checked so the end_io handlers know about it
+ */
+ ASSERT(!bio_flagged(bio, BIO_CLONED));
+ bio_for_each_segment_all(bvec, cb->orig_bio, iter_all)
+ SetPageChecked(bvec->bv_page);
+
+ bio_endio(cb->orig_bio);
+ }
+
+ /* finally free the cb struct */
+ kfree(cb->compressed_pages);
+ kfree(cb);
+}
+
/* when we finish reading compressed pages from the disk, we
* decompress them and then run the bio end_io routines on the
* decompressed pages (in the inode address space).
@@ -235,8 +273,6 @@ static void end_compressed_bio_read(struct bio *bio)
{
struct compressed_bio *cb = bio->bi_private;
struct inode *inode;
- struct page *page;
- unsigned int index;
unsigned int mirror = btrfs_io_bio(bio)->mirror_num;
int ret = 0;
@@ -271,36 +307,7 @@ static void end_compressed_bio_read(struct bio *bio)
csum_failed:
if (ret)
cb->errors = 1;
-
- /* release the compressed pages */
- index = 0;
- for (index = 0; index < cb->nr_pages; index++) {
- page = cb->compressed_pages[index];
- page->mapping = NULL;
- put_page(page);
- }
-
- /* do io completion on the original bio */
- if (cb->errors) {
- bio_io_error(cb->orig_bio);
- } else {
- struct bio_vec *bvec;
- struct bvec_iter_all iter_all;
-
- /*
- * we have verified the checksum already, set page
- * checked so the end_io handlers know about it
- */
- ASSERT(!bio_flagged(bio, BIO_CLONED));
- bio_for_each_segment_all(bvec, cb->orig_bio, iter_all)
- SetPageChecked(bvec->bv_page);
-
- bio_endio(cb->orig_bio);
- }
-
- /* finally free the cb struct */
- kfree(cb->compressed_pages);
- kfree(cb);
+ finish_compressed_bio_read(cb, bio);
out:
bio_put(bio);
}
@@ -426,6 +433,7 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
return BLK_STS_RESOURCE;
atomic_set(&cb->pending_bios, 0);
atomic_set(&cb->io_sectors, compressed_len >> fs_info->sectorsize_bits);
+ init_waitqueue_head(&cb->pending_bio_wait);
cb->errors = 0;
cb->inode = &inode->vfs_inode;
cb->start = start;
@@ -709,6 +717,7 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
atomic_set(&cb->pending_bios, 0);
atomic_set(&cb->io_sectors, compressed_len >> fs_info->sectorsize_bits);
+ init_waitqueue_head(&cb->pending_bio_wait);
cb->errors = 0;
cb->inode = inode;
cb->mirror_num = mirror_num;
@@ -784,20 +793,20 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
atomic_inc(&cb->pending_bios);
ret = btrfs_bio_wq_end_io(fs_info, comp_bio,
BTRFS_WQ_ENDIO_DATA);
- BUG_ON(ret); /* -ENOMEM */
+ if (ret)
+ goto finish_cb;
ret = btrfs_lookup_bio_sums(inode, comp_bio, sums);
- BUG_ON(ret); /* -ENOMEM */
+ if (ret)
+ goto finish_cb;
nr_sectors = DIV_ROUND_UP(comp_bio->bi_iter.bi_size,
fs_info->sectorsize);
sums += fs_info->csum_size * nr_sectors;
ret = btrfs_map_bio(fs_info, comp_bio, mirror_num);
- if (ret) {
- comp_bio->bi_status = ret;
- bio_endio(comp_bio);
- }
+ if (ret)
+ goto finish_cb;
comp_bio = btrfs_bio_alloc(cur_disk_byte);
comp_bio->bi_opf = REQ_OP_READ;
@@ -811,16 +820,16 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
atomic_inc(&cb->pending_bios);
ret = btrfs_bio_wq_end_io(fs_info, comp_bio, BTRFS_WQ_ENDIO_DATA);
- BUG_ON(ret); /* -ENOMEM */
+ if (ret)
+ goto last_bio;
ret = btrfs_lookup_bio_sums(inode, comp_bio, sums);
- BUG_ON(ret); /* -ENOMEM */
+ if (ret)
+ goto last_bio;
ret = btrfs_map_bio(fs_info, comp_bio, mirror_num);
- if (ret) {
- comp_bio->bi_status = ret;
- bio_endio(comp_bio);
- }
+ if (ret)
+ goto last_bio;
return 0;
@@ -836,6 +845,27 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
out:
free_extent_map(em);
return ret;
+last_bio:
+ cb->errors = 1;
+ comp_bio->bi_status = ret;
+ /* This is the last bio, endio functions will free @cb */
+ bio_endio(comp_bio);
+ return ret;
+finish_cb:
+ cb->errors = 1;
+ if (comp_bio) {
+ comp_bio->bi_status = ret;
+ bio_endio(comp_bio);
+ }
+ /*
+ * Even with previous bio ended, we should still have io not yet
+ * submitted, thus need to finish @cb manually.
+ */
+ ASSERT(atomic_read(&cb->io_sectors));
+ wait_event(cb->pending_bio_wait, atomic_read(&cb->pending_bios) == 0);
+ /* Now we are the only one referring @cb, can finish it safely. */
+ finish_compressed_bio_read(cb, NULL);
+ return ret;
}
/*
@@ -39,6 +39,9 @@ struct compressed_bio {
*/
atomic_t io_sectors;
+ /* To wait for any submitted bio, used in error handling */
+ wait_queue_head_t pending_bio_wait;
+
/* Number of compressed pages in the array */
unsigned int nr_pages;
There are quite some BUG_ON()s inside btrfs_submit_compressed_read(), namingly all errors inside the for() loop relies on BUG_ON() to handle -ENOMEM. Hunt down these BUG_ON()s properly by: - Introduce compressed_bio::pending_bios_wait This allows us to wait for any submitted bio to finish, while still keeps the compressed_bio from being freed, as we should have compressed_bio::io_sectors not zero. - Introduce finish_compressed_bio_read() to finish the compressed_bio - Properly end the bio and finish compressed_bio when error happens Now in btrfs_submit_compressed_read() even when the bio submission failed, we can properly handle the error without triggering BUG_ON(). Signed-off-by: Qu Wenruo <wqu@suse.com> --- fs/btrfs/compression.c | 118 ++++++++++++++++++++++++++--------------- fs/btrfs/compression.h | 3 ++ 2 files changed, 77 insertions(+), 44 deletions(-)