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 Conflicts: fs/btrfs/extent_io.c [yyl: adjust context] --- fs/btrfs/extent_io.c | 54 ++++++++++++++++++++++++++++++++------------ 1 file changed, 40 insertions(+), 14 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 92a156af4bf1..033f1b632b88 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -160,15 +160,28 @@ static int __must_check submit_one_bio(struct bio *bio, int mirror_num, 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) @@ -3552,7 +3565,8 @@ lock_extent_buffer_for_io(struct extent_buffer *eb,
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); }
@@ -3561,7 +3575,8 @@ lock_extent_buffer_for_io(struct extent_buffer *eb, 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) { @@ -3602,7 +3617,8 @@ lock_extent_buffer_for_io(struct extent_buffer *eb,
if (!trylock_page(p)) { if (!flush) { - flush_write_bio(epd); + ret = flush_write_bio(epd); + BUG_ON(ret < 0); flush = 1; } lock_page(p); @@ -3793,6 +3809,7 @@ int btree_write_cache_pages(struct address_space *mapping, .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; @@ -3920,7 +3937,7 @@ int btree_write_cache_pages(struct address_space *mapping, * if the fs already has error. */ if (!test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) { - flush_write_bio(&epd); + ret = flush_write_bio(&epd); } else { ret = -EUCLEAN; end_write_bio(&epd, ret); @@ -4021,7 +4038,8 @@ static int extent_write_cache_pages(struct address_space *mapping, * tmpfs file mapping */ if (!trylock_page(page)) { - flush_write_bio(epd); + ret = flush_write_bio(epd); + BUG_ON(ret < 0); lock_page(page); }
@@ -4031,8 +4049,10 @@ static int extent_write_cache_pages(struct address_space *mapping, }
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); }
@@ -4091,6 +4111,7 @@ static int extent_write_cache_pages(struct address_space *mapping, 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, @@ -4105,7 +4126,8 @@ int extent_write_full_page(struct page *page, struct writeback_control *wbc) return ret; }
- flush_write_bio(&epd); + flush_ret = flush_write_bio(&epd); + BUG_ON(flush_ret < 0); return ret; }
@@ -4113,6 +4135,7 @@ int extent_write_locked_range(struct inode *inode, u64 start, u64 end, 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; @@ -4147,7 +4170,8 @@ int extent_write_locked_range(struct inode *inode, u64 start, u64 end, start += PAGE_SIZE; }
- flush_write_bio(&epd); + flush_ret = flush_write_bio(&epd); + BUG_ON(flush_ret < 0); return ret; }
@@ -4155,6 +4179,7 @@ int extent_writepages(struct address_space *mapping, struct writeback_control *wbc) { int ret = 0; + int flush_ret; struct extent_page_data epd = { .bio = NULL, .tree = &BTRFS_I(mapping->host)->io_tree, @@ -4163,7 +4188,8 @@ int extent_writepages(struct address_space *mapping, };
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; }