The -EIO returned here can end up overriding whatever error is marked in the address space, and be returned at fsync time, even when there is a more appropriate error stored in the mapping. Read errors are also sometimes tracked on a per-page level using PG_error. Suppose we have a read error on a page, and then that page is subsequently dirtied by overwriting the whole page. Writeback doesn't clear PG_error, so we can then end up successfully writing back that page and still return -EIO on fsync. Worse yet, PG_error is cleared during a sync() syscall, but the -EIO return from that is silently discarded. Any subsystem that is relying on PG_error to report errors during fsync can easily lose writeback errors due to this. All you need is a stray sync() call on the box at the wrong time and you've lost the error. Since the handling of the PG_error flag is somewhat inconsistent across subsystems, let's just rely on marking the address space when there are writeback errors. Change the TestClearPageError call to ClearPageError, and make __filemap_fdatawait_range a void return function. Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> --- mm/filemap.c | 19 +++++-------------- 1 file changed, 5 insertions(+), 14 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index d94a76d4e023..47e7f50fb830 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -363,17 +363,16 @@ int filemap_flush(struct address_space *mapping) } EXPORT_SYMBOL(filemap_flush); -static int __filemap_fdatawait_range(struct address_space *mapping, +static void __filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte, loff_t end_byte) { pgoff_t index = start_byte >> PAGE_SHIFT; pgoff_t end = end_byte >> PAGE_SHIFT; struct pagevec pvec; int nr_pages; - int ret = 0; if (end_byte < start_byte) - goto out; + return; pagevec_init(&pvec, 0); while ((index <= end) && @@ -390,14 +389,11 @@ static int __filemap_fdatawait_range(struct address_space *mapping, continue; wait_on_page_writeback(page); - if (TestClearPageError(page)) - ret = -EIO; + ClearPageError(page); } pagevec_release(&pvec); cond_resched(); } -out: - return ret; } /** @@ -417,15 +413,10 @@ static int __filemap_fdatawait_range(struct address_space *mapping, int filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte, loff_t end_byte) { - int ret, ret2; errseq_t since = filemap_sample_wb_error(mapping); - ret = __filemap_fdatawait_range(mapping, start_byte, end_byte); - ret2 = filemap_check_wb_error(mapping, since); - if (!ret) - ret = ret2; - - return ret; + __filemap_fdatawait_range(mapping, start_byte, end_byte); + return filemap_check_wb_error(mapping, since); } EXPORT_SYMBOL(filemap_fdatawait_range); -- 2.9.3