From 941b853d779de3298e39f1eb4e252984464eaea8 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 11 Jan 2011 07:24:01 -0500 Subject: [PATCH] cifs: don't fail writepages on -EAGAIN errors If CIFSSMBWrite2 returns -EAGAIN, then the error should be considered temporary. CIFS should retry the write instead of setting an error on the mapping and returning. For WB_SYNC_ALL, just retry the write immediately. In the WB_SYNC_NONE case, call redirty_page_for_writeback on all of the pages that didn't get written out and then move on. Also, fix up the handling of a short write with a successful return code. MS-CIFS says that 0 bytes_written means ENOSPC or EFBIG. It doesn't mention what a short, but non-zero write means, so for now treat it as we would an -EAGAIN return. Reviewed-by: Suresh Jayaraman Reviewed-by: Pavel Shilovsky Signed-off-by: Jeff Layton Signed-off-by: Steve French --- fs/cifs/file.c | 49 +++++++++++++++++++++++++++++++++++++------------ 1 file changed, 37 insertions(+), 12 deletions(-) diff --git a/fs/cifs/file.c b/fs/cifs/file.c index af371910f54..cfa2e5ebcaf 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -1377,6 +1377,7 @@ retry: break; } if (n_iov) { +retry_write: open_file = find_writable_file(CIFS_I(mapping->host), false); if (!open_file) { @@ -1389,31 +1390,55 @@ retry: &bytes_written, iov, n_iov, long_op); cifsFileInfo_put(open_file); - cifs_update_eof(cifsi, offset, bytes_written); } - if (rc || bytes_written < bytes_to_write) { - cERROR(1, "Write2 ret %d, wrote %d", - rc, bytes_written); - mapping_set_error(mapping, rc); - } else { + cFYI(1, "Write2 rc=%d, wrote=%u", rc, bytes_written); + + /* + * For now, treat a short write as if nothing got + * written. A zero length write however indicates + * ENOSPC or EFBIG. We have no way to know which + * though, so call it ENOSPC for now. EFBIG would + * get translated to AS_EIO anyway. + * + * FIXME: make it take into account the data that did + * get written + */ + if (rc == 0) { + if (bytes_written == 0) + rc = -ENOSPC; + else if (bytes_written < bytes_to_write) + rc = -EAGAIN; + } + + /* retry on data-integrity flush */ + if (wbc->sync_mode == WB_SYNC_ALL && rc == -EAGAIN) + goto retry_write; + + /* fix the stats and EOF */ + if (bytes_written > 0) { cifs_stats_bytes_written(tcon, bytes_written); + cifs_update_eof(cifsi, offset, bytes_written); } for (i = 0; i < n_iov; i++) { page = pvec.pages[first + i]; - /* Should we also set page error on - success rc but too little data written? */ - /* BB investigate retry logic on temporary - server crash cases and how recovery works - when page marked as error */ - if (rc) + /* on retryable write error, redirty page */ + if (rc == -EAGAIN) + redirty_page_for_writepage(wbc, page); + else if (rc != 0) SetPageError(page); kunmap(page); unlock_page(page); end_page_writeback(page); page_cache_release(page); } + + if (rc != -EAGAIN) + mapping_set_error(mapping, rc); + else + rc = 0; + if ((wbc->nr_to_write -= n_iov) <= 0) done = 1; index = next; -- 2.20.1