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cifs: don't fail writepages on -EAGAIN errors

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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 <sjayaraman@suse.de>
Reviewed-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This commit is contained in:
Jeff Layton 2011-01-11 07:24:01 -05:00 committed by Steve French
parent 12fed00de9
commit 941b853d77
1 changed files with 37 additions and 12 deletions
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49
fs/cifs/file.c
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@ -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;