The patch titled
direct-io-sync-and-invalidate-file-region-when-falling-back-to-buffered-write fix
has been added to the -mm tree. Its filename is
direct-io-sync-and-invalidate-file-region-when-falling-back-to-buffered-write-fix.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: direct-io-sync-and-invalidate-file-region-when-falling-back-to-buffered-write fix
From: Jeff Moyer <jmoyer@xxxxxxxxxx>
akpm> /*
akpm> * We need to ensure that the page cache pages are written to
akpm> * disk and invalidated to preserve the expected O_DIRECT
akpm> * semantics.
akpm> */
akpm> endbyte = pos + written_buffered - 1;
We probably want to handle the case where generic_file_buffered_write
returns an error or nothing written.
akpm> err = do_sync_file_range(file, pos, endbyte,
akpm> SYNC_FILE_RANGE_WAIT_BEFORE|
akpm> SYNC_FILE_RANGE_WRITE|
akpm> SYNC_FILE_RANGE_WAIT_AFTER);
akpm> if (err == 0) {
akpm> written += written_buffered;
akpm> invalidate_mapping_pages(mapping,
akpm> pos >> PAGE_CACHE_SHIFT,
akpm> endbyte >> PAGE_CACHE_SHIFT);
generic_file_buffered_write takes written as an argument, and returns that
amount plus whatever it managed to write. As such, you don't want to add
written_buffered to written. Instead, you want written = written_buffered.
The endbyte calculation has to be altered in kind.
Incremental, locally tested patch attached. Comments are welcome as
always. Once there is consensus, I'll send this off for testing with
Oracle again.
Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cc: Zach Brown <zach.brown@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
mm/filemap.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff -puN mm/filemap.c~direct-io-sync-and-invalidate-file-region-when-falling-back-to-buffered-write-fix mm/filemap.c
--- a/mm/filemap.c~direct-io-sync-and-invalidate-file-region-when-falling-back-to-buffered-write-fix
+++ a/mm/filemap.c
@@ -2291,19 +2291,21 @@ __generic_file_aio_write_nolock(struct k
written_buffered = generic_file_buffered_write(iocb, iov,
nr_segs, pos, ppos, count,
written);
+ if (written_buffered < 0 || written_buffered == written)
+ goto out;
/*
* We need to ensure that the page cache pages are written to
* disk and invalidated to preserve the expected O_DIRECT
* semantics.
*/
- endbyte = pos + written_buffered - 1;
+ endbyte = pos + written_buffered - written - 1;
err = do_sync_file_range(file, pos, endbyte,
SYNC_FILE_RANGE_WAIT_BEFORE|
SYNC_FILE_RANGE_WRITE|
SYNC_FILE_RANGE_WAIT_AFTER);
if (err == 0) {
- written += written_buffered;
+ written = written_buffered;
invalidate_mapping_pages(mapping,
pos >> PAGE_CACHE_SHIFT,
endbyte >> PAGE_CACHE_SHIFT);
_
Patches currently in -mm which might be from jmoyer@xxxxxxxxxx are
direct-io-sync-and-invalidate-file-region-when-falling-back-to-buffered-write.patch
direct-io-sync-and-invalidate-file-region-when-falling-back-to-buffered-write-fix.patch
dio-centralize-completion-in-dio_complete.patch
dio-call-blk_run_address_space-once-per-op.patch
dio-formalize-bio-counters-as-a-dio-reference-count.patch
dio-remove-duplicate-bio-wait-code.patch
dio-only-call-aio_complete-after-returning-eiocbqueued.patch
-
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