From: Qu Wenruo wqu@suse.com
commit f4340622e02261fae599e3da936ff4808b418173 upstream.
We have a BUG_ON() in flush_write_bio() to handle the return value of submit_one_bio().
Move the BUG_ON() one level up to all its callers.
This patch will introduce temporary variable, @flush_ret to keep code change minimal in this patch. That variable will be cleaned up when enhancing the error handling later.
Reviewed-by: Johannes Thumshirn jthumshirn@suse.de Signed-off-by: Qu Wenruo wqu@suse.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com [bwh: Cherry-picked for 4.19 to ease backporting later fixes] Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/extent_io.c | 55 ++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 41 insertions(+), 14 deletions(-)
--- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -160,15 +160,28 @@ static int __must_check submit_one_bio(s return blk_status_to_errno(ret); }
-static void flush_write_bio(struct extent_page_data *epd) +/* + * Submit bio from extent page data via submit_one_bio + * + * Return 0 if everything is OK. + * Return <0 for error. + */ +static int __must_check flush_write_bio(struct extent_page_data *epd) { - if (epd->bio) { - int ret; + int ret = 0;
+ if (epd->bio) { ret = submit_one_bio(epd->bio, 0, 0); - BUG_ON(ret < 0); /* -ENOMEM */ + /* + * Clean up of epd->bio is handled by its endio function. + * And endio is either triggered by successful bio execution + * or the error handler of submit bio hook. + * So at this point, no matter what happened, we don't need + * to clean up epd->bio. + */ epd->bio = NULL; } + return ret; }
int __init extent_io_init(void) @@ -3538,7 +3551,8 @@ lock_extent_buffer_for_io(struct extent_
if (!btrfs_try_tree_write_lock(eb)) { flush = 1; - flush_write_bio(epd); + ret = flush_write_bio(epd); + BUG_ON(ret < 0); btrfs_tree_lock(eb); }
@@ -3547,7 +3561,8 @@ lock_extent_buffer_for_io(struct extent_ if (!epd->sync_io) return 0; if (!flush) { - flush_write_bio(epd); + ret = flush_write_bio(epd); + BUG_ON(ret < 0); flush = 1; } while (1) { @@ -3588,7 +3603,8 @@ lock_extent_buffer_for_io(struct extent_
if (!trylock_page(p)) { if (!flush) { - flush_write_bio(epd); + ret = flush_write_bio(epd); + BUG_ON(ret < 0); flush = 1; } lock_page(p); @@ -3779,6 +3795,7 @@ int btree_write_cache_pages(struct addre .sync_io = wbc->sync_mode == WB_SYNC_ALL, }; int ret = 0; + int flush_ret; int done = 0; int nr_to_write_done = 0; struct pagevec pvec; @@ -3878,7 +3895,8 @@ retry: index = 0; goto retry; } - flush_write_bio(&epd); + flush_ret = flush_write_bio(&epd); + BUG_ON(flush_ret < 0); return ret; }
@@ -3975,7 +3993,8 @@ retry: * tmpfs file mapping */ if (!trylock_page(page)) { - flush_write_bio(epd); + ret = flush_write_bio(epd); + BUG_ON(ret < 0); lock_page(page); }
@@ -3985,8 +4004,10 @@ retry: }
if (wbc->sync_mode != WB_SYNC_NONE) { - if (PageWriteback(page)) - flush_write_bio(epd); + if (PageWriteback(page)) { + ret = flush_write_bio(epd); + BUG_ON(ret < 0); + } wait_on_page_writeback(page); }
@@ -4045,6 +4066,7 @@ retry: int extent_write_full_page(struct page *page, struct writeback_control *wbc) { int ret; + int flush_ret; struct extent_page_data epd = { .bio = NULL, .tree = &BTRFS_I(page->mapping->host)->io_tree, @@ -4054,7 +4076,8 @@ int extent_write_full_page(struct page *
ret = __extent_writepage(page, wbc, &epd);
- flush_write_bio(&epd); + flush_ret = flush_write_bio(&epd); + BUG_ON(flush_ret < 0); return ret; }
@@ -4062,6 +4085,7 @@ int extent_write_locked_range(struct ino int mode) { int ret = 0; + int flush_ret; struct address_space *mapping = inode->i_mapping; struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree; struct page *page; @@ -4096,7 +4120,8 @@ int extent_write_locked_range(struct ino start += PAGE_SIZE; }
- flush_write_bio(&epd); + flush_ret = flush_write_bio(&epd); + BUG_ON(flush_ret < 0); return ret; }
@@ -4104,6 +4129,7 @@ int extent_writepages(struct address_spa struct writeback_control *wbc) { int ret = 0; + int flush_ret; struct extent_page_data epd = { .bio = NULL, .tree = &BTRFS_I(mapping->host)->io_tree, @@ -4112,7 +4138,8 @@ int extent_writepages(struct address_spa };
ret = extent_write_cache_pages(mapping, wbc, &epd); - flush_write_bio(&epd); + flush_ret = flush_write_bio(&epd); + BUG_ON(flush_ret < 0); return ret; }