kernel/git/stable/linux.git/mm/filemap.c, branch linux-2.6.21.y

[PATCH] dio: invalidate clean pages before dio write

2007-03-17T02:25:04+00:00

This patch fixes a user-triggerable oops that was reported by Leonid Ananiev as archived at http://lkml.org/lkml/2007/2/8/337. dio writes invalidate clean pages that intersect the written region so that subsequent buffered reads go to disk to read the new data. If this fails the interface tries to tell the caller that the cache is inconsistent by returning EIO. Before this patch we had the problem where this invalidation failure would clobber -EIOCBQUEUED as it made its way from fs/direct-io.c to fs/aio.c. Both fs/aio.c and bio completion call aio_complete() and we reference freed memory, usually oopsing. This patch addresses this problem by invalidating before the write so that we can cleanly return -EIO before ->direct_IO() has had a chance to return -EIOCBQUEUED. There is a compromise here. During the dio write we can fault in mmap()ed pages which intersect the written range with get_user_pages() if the user provided them for the source buffer. This is a crazy thing to do, but we can make it mostly work in most cases by trying the invalidation again. The compromise is that we won't return an error if this second invalidation fails if it's an AIO write and we have -EIOCBQUEUED. This was tested by having two processes race performing large O_DIRECT and buffered ordered writes. Within minutes ext3 would see a race between ext3_releasepage() and jbd holding a reference on ordered data buffers and would cause invalidation to fail, panicing the box. The test can be found in the 'aio_dio_bugs' test group in test.kernel.org/autotest. After this patch the test passes. Signed-off-by: Zach Brown Signed-off-by: Benjamin LaHaise Cc: Leonid Ananiev Cc: Nick Piggin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] knfsd: stop NFSD writes from being broken into lots of little writes to filesystem

2007-02-16T16:14:01+00:00

When NFSD receives a write request, the data is typically in a number of 1448 byte segments and writev is used to collect them together. Unfortunately, generic_file_buffered_write passes these to the filesystem one at a time, so an e.g. 32K over-write becomes a series of partial-page writes to each page, causing the filesystem to have to pre-read those pages - wasted effort. generic_file_buffered_write handles one segment of the vector at a time as it has to pre-fault in each segment to avoid deadlocks. When writing from kernel-space (and nfsd does) this is not an issue, so generic_file_buffered_write does not need to break and iovec from nfsd into little pieces. This patch avoids the splitting when get_fs is KERNEL_DS as it is from NFSd. This issue was introduced by commit 6527c2bdf1f833cc18e8f42bd97973d583e4aa83 Acked-by: Nick Piggin Cc: Norman Weathers Cc: Vladimir V. Saveliev Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Numerous fixes to kernel-doc info in source files.

2007-02-11T18:51:32+00:00

A variety of (mostly) innocuous fixes to the embedded kernel-doc content in source files, including: * make multi-line initial descriptions single line * denote some function names, constants and structs as such * change erroneous opening '/*' to '/**' in a few places * reword some text for clarity Signed-off-by: Robert P. J. Day Cc: "Randy.Dunlap" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] mm: remove find_trylock_page

2007-02-09T16:06:14+00:00

Remove find_trylock_page as per the removal schedule. Signed-off-by: Nick Piggin [ Let's see if anybody screams ] Signed-off-by: Linus Torvalds

[PATCH] dio: only call aio_complete() after returning -EIOCBQUEUED

2006-12-10T17:57:21+00:00

The only time it is safe to call aio_complete() is when the ->ki_retry function returns -EIOCBQUEUED to the AIO core. direct_io_worker() has historically done this by relying on its caller to translate positive return codes into -EIOCBQUEUED for the aio case. It did this by trying to keep conditionals in sync. direct_io_worker() knew when finished_one_bio() was going to call aio_complete(). It would reverse the test and wait and free the dio in the cases it thought that finished_one_bio() wasn't going to. Not surprisingly, it ended up getting it wrong. 'ret' could be a negative errno from the submission path but it failed to communicate this to finished_one_bio(). direct_io_worker() would return < 0, it's callers wouldn't raise -EIOCBQUEUED, and aio_complete() would be called. In the future finished_one_bio()'s tests wouldn't reflect this and aio_complete() would be called for a second time which can manifest as an oops. The previous cleanups have whittled the sync and async completion paths down to the point where we can collapse them and clearly reassert the invariant that we must only call aio_complete() after returning -EIOCBQUEUED. direct_io_worker() will only return -EIOCBQUEUED when it is not the last to drop the dio refcount and the aio bio completion path will only call aio_complete() when it is the last to drop the dio refcount. direct_io_worker() can ensure that it is the last to drop the reference count by waiting for bios to drain. It does this for sync ops, of course, and for partial dio writes that must fall back to buffered and for aio ops that saw errors during submission. This means that operations that end up waiting, even if they were issued as aio ops, will not call aio_complete() from dio. Instead we return the return code of the operation and let the aio core call aio_complete(). This is purposely done to fix a bug where AIO DIO file extensions would call aio_complete() before their callers have a chance to update i_size. Now that direct_io_worker() is explicitly returning -EIOCBQUEUED its callers no longer have to translate for it. XFS needs to be careful not to free resources that will be used during AIO completion if -EIOCBQUEUED is returned. We maintain the previous behaviour of trying to write fs metadata for O_SYNC aio+dio writes. Signed-off-by: Zach Brown Cc: Badari Pulavarty Cc: Suparna Bhattacharya Acked-by: Jeff Moyer Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path

2006-12-08T16:28:43+00:00

Change all the uses of f_{dentry,vfsmnt} to f_path.{dentry,mnt} in linux/mm/. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] grab swap token reordered

2006-12-07T16:39:21+00:00

Make sure the contention for the token happens _before_ any read-in and kicks the swap-token algo only when the VM is under pressure. Signed-off-by: Ashwin Chaugule Cc: Rik van Riel Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Export should_remove_suid()

2006-12-02T02:28:38+00:00

This helps us avoid replicating the same logic within file system drivers. Signed-off-by: Mark Fasheh

[PATCH] mm: clean up pagecache allocation

2006-10-28T18:30:50+00:00

- Consolidate page_cache_alloc - Fix splice: only the pagecache pages and filesystem data need to use mapping_gfp_mask. - Fix grab_cache_page_nowait: same as splice, also honour NUMA placement. Signed-off-by: Nick Piggin Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'splice' of git://brick.kernel.dk/data/git/linux-2.6-block

2006-10-21T17:01:52+00:00

* 'splice' of git://brick.kernel.dk/data/git/linux-2.6-block: [PATCH] Remove SUID when splicing into an inode [PATCH] Add lockless helpers for remove_suid() [PATCH] Introduce generic_file_splice_write_nolock() [PATCH] Take i_mutex in splice_from_pipe()