linux-stable.git/fs/nfs/write.c, branch linux-3.7.y

NFS: Ensure that we free the rpc_task after read and write cleanups are done

2013-01-11T17:18:38+00:00

commit 6db6dd7d3fd8f7c765dabc376493d6791ab28bd6 upstream.

This patch ensures that we free the rpc_task after the cleanup callbacks
are done in order to avoid a deadlock problem that can be triggered if
the callback needs to wait for another workqueue item to complete.

Signed-off-by: Trond Myklebust 
Cc: Weston Andros Adamson 
Cc: Tejun Heo 
Cc: Bruce Fields 
Signed-off-by: Greg Kroah-Hartman

NFS: Don't use SetPageError in the NFS writeback code

2013-01-11T17:18:37+00:00

commit ada8e20d044c0fa5610e504ce6fb4578ebd3edd9 upstream.

The writeback code is already capable of passing errors back to user space
by means of the open_context->error. In the case of ENOSPC, Neil Brown
is reporting seeing 2 errors being returned.

Neil writes:

"e.g. if /mnt2/ if an nfs mounted filesystem that has no space then

strace dd if=/dev/zero conv=fsync >> /mnt2/afile count=1

reported Input/output error and the relevant parts of the strace output are:

write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 512) = 512
fsync(1)                                = -1 EIO (Input/output error)
close(1)                                = -1 ENOSPC (No space left on device)"

Neil then shows that the duplication of error messages appears to be due to
the use of the PageError() mechanism, which causes filemap_fdatawait_range
to return the extra EIO. The regression was introduced by
commit 7b281ee026552f10862b617a2a51acf49c829554 (NFS: fsync() must exit
with an error if page writeback failed).

Fix this by removing the call to SetPageError(), and just relying on
open_context->error reporting the ENOSPC back to fsync().

Reported-by: Neil Brown 
Tested-by: Neil Brown 
Signed-off-by: Trond Myklebust 
Signed-off-by: Greg Kroah-Hartman

nfs: don't extend writes to cover entire page if pagecache is invalid

2013-01-11T17:18:36+00:00

commit 81d9bce5309288086b58b4d97a644e495fef75f2 upstream.

Jian reported that the following sequence would leave "testfile" with
corrupt data:

    # mount localhost:/export /mnt/nfs/ -o vers=3
    # echo abc > /mnt/nfs/testfile; echo def >> /export/testfile; echo ghi >> /mnt/nfs/testfile
    # cat -v /export/testfile
    abc
    ^@^@^@^@ghi

While there's no locking involved here, the operations are serialized,
so CTO should prevent corruption.

The first write to the file is fine and writes 4 bytes. The file is then
extended on the server. When it's reopened a GETATTR is issued and the
size change is noticed. This causes NFS_INO_INVALID_DATA to be set on
the file. Because the file is opened for write only,
nfs_want_read_modify_write() returns 0 to nfs_write_begin().
nfs_updatepage then calls nfs_write_pageuptodate() to see if it should
extend the nfs_page to cover the whole page. NFS_INO_INVALID_DATA is
still set on the file at that point, but that flag is ignored and
nfs_pageuptodate erroneously extends the write to cover the whole page,
with the write done on the server side filled in with zeroes.

This patch just has that function check for NFS_INO_INVALID_DATA in
addition to NFS_INO_REVAL_PAGECACHE. This fixes the bug, but looking
over the code, I wonder if we might have a similar bug in
nfs_revalidate_size(). The difference between those two flags is very
subtle, so it seems like we ought to be checking for
NFS_INO_INVALID_DATA in most of the places that we look for
NFS_INO_REVAL_PAGECACHE.

I believe this is regression introduced by commit 8d197a568. The code
did check for NFS_INO_INVALID_DATA prior to that patch.

Original bug report is here:

    https://bugzilla.redhat.com/show_bug.cgi?id=885743

Reported-by: Jian Li 
Signed-off-by: Jeff Layton 
Signed-off-by: Trond Myklebust 
Signed-off-by: Greg Kroah-Hartman

NFS: Fix fdatasync/fsync() when confronted with a server reboot

2012-09-28T20:03:05+00:00

If the server reboots before it can commit the unstable writes to disk,
then nfs_commit_release_pages() will detect this when it compares the
verifier returned by COMMIT to the one returned by WRITE. When this
happens, the client needs to resend those writes in order to guarantee
that they make it to stable storage.

This patch adds a signalling mechanism to notify fsync() that it
needs to retry all writes before it can exit.

Signed-off-by: Trond Myklebust

NFS: Clean up helper function nfs4_select_rw_stateid()

2012-09-28T20:03:04+00:00

We want to be able to pass on the information that the page was not
dirtied under a lock. Instead of adding a flag parameter, do this
by passing a pointer to a 'struct nfs_lock_owner' that may be NULL.

Also reuse this structure in struct nfs_lock_context to carry the
fl_owner_t and pid_t.

Signed-off-by: Trond Myklebust

nfs: tear down caches in nfs_init_writepagecache when allocation fails

2012-08-02T21:36:07+00:00

...and ensure that we tear down the nfs_commit_data cache too when
unloading the module.

Cc: Bryan Schumaker 
Cc: stable@vger.kernel.org
Signed-off-by: Jeff Layton 
Signed-off-by: Trond Myklebust

Merge branch 'akpm' (Andrew's patch-bomb)

2012-08-01T02:25:39+00:00

Merge Andrew's second set of patches:
 - MM
 - a few random fixes
 - a couple of RTC leftovers

* emailed patches from Andrew Morton : (120 commits)
  rtc/rtc-88pm80x: remove unneed devm_kfree
  rtc/rtc-88pm80x: assign ret only when rtc_register_driver fails
  mm: hugetlbfs: close race during teardown of hugetlbfs shared page tables
  tmpfs: distribute interleave better across nodes
  mm: remove redundant initialization
  mm: warn if pg_data_t isn't initialized with zero
  mips: zero out pg_data_t when it's allocated
  memcg: gix memory accounting scalability in shrink_page_list
  mm/sparse: remove index_init_lock
  mm/sparse: more checks on mem_section number
  mm/sparse: optimize sparse_index_alloc
  memcg: add mem_cgroup_from_css() helper
  memcg: further prevent OOM with too many dirty pages
  memcg: prevent OOM with too many dirty pages
  mm: mmu_notifier: fix freed page still mapped in secondary MMU
  mm: memcg: only check anon swapin page charges for swap cache
  mm: memcg: only check swap cache pages for repeated charging
  mm: memcg: split swapin charge function into private and public part
  mm: memcg: remove needless !mm fixup to init_mm when charging
  mm: memcg: remove unneeded shmem charge type
  ...

nfs: prevent page allocator recursions with swap over NFS.

2012-08-01T01:42:48+00:00

GFP_NOFS is _more_ permissive than GFP_NOIO in that it will initiate IO,
just not of any filesystem data.

The problem is that previously NOFS was correct because that avoids
recursion into the NFS code.  With swap-over-NFS, it is no longer correct
as swap IO can lead to this recursion.

Signed-off-by: Peter Zijlstra 
Signed-off-by: Mel Gorman 
Acked-by: Rik van Riel 
Cc: Christoph Hellwig 
Cc: David S. Miller 
Cc: Eric B Munson 
Cc: Eric Paris 
Cc: James Morris 
Cc: Mel Gorman 
Cc: Mike Christie 
Cc: Neil Brown 
Cc: Sebastian Andrzej Siewior 
Cc: Trond Myklebust 
Cc: Xiaotian Feng 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

nfs: disable data cache revalidation for swapfiles

2012-08-01T01:42:47+00:00

The VM does not like PG_private set on PG_swapcache pages.  As suggested
by Trond in http://lkml.org/lkml/2006/8/25/348, this patch disables NFS
data cache revalidation on swap files.  as it does not make sense to have
other clients change the file while it is being used as swap.  This avoids
setting PG_private on swap pages, since there ought to be no further races
with invalidate_inode_pages2() to deal with.

Since we cannot set PG_private we cannot use page->private which is
already used by PG_swapcache pages to store the nfs_page.  Thus augment
the new nfs_page_find_request logic.

Signed-off-by: Peter Zijlstra 
Signed-off-by: Mel Gorman 
Acked-by: Rik van Riel 
Cc: Christoph Hellwig 
Cc: David S. Miller 
Cc: Eric B Munson 
Cc: Eric Paris 
Cc: James Morris 
Cc: Mel Gorman 
Cc: Mike Christie 
Cc: Neil Brown 
Cc: Sebastian Andrzej Siewior 
Cc: Trond Myklebust 
Cc: Xiaotian Feng 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

nfs: teach the NFS client how to treat PG_swapcache pages

2012-08-01T01:42:47+00:00

Replace all relevant occurences of page->index and page->mapping in the
NFS client with the new page_file_index() and page_file_mapping()
functions.

Signed-off-by: Peter Zijlstra 
Signed-off-by: Mel Gorman 
Acked-by: Rik van Riel 
Cc: Christoph Hellwig 
Cc: David S. Miller 
Cc: Eric B Munson 
Cc: Eric Paris 
Cc: James Morris 
Cc: Mel Gorman 
Cc: Mike Christie 
Cc: Neil Brown 
Cc: Sebastian Andrzej Siewior 
Cc: Trond Myklebust 
Cc: Xiaotian Feng 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds