linux.git/fs/cifs, branch v3.15

cifs: fix actimeo=0 corner case when cifs_i->time == jiffies

2014-04-25T03:37:03+00:00

actimeo=0 is supposed to be a special case that ensures that inode
attributes are always refetched from the server instead of trusting the
cache. The cifs code however uses time_in_range() to determine whether
the attributes have timed out. In the case where cifs_i->time equals
jiffies, this leads to the cifs code not refetching the inode attributes
when it should.

Fix this by explicitly testing for actimeo=0, and handling it as a
special case.

Reported-and-tested-by: Tetsuo Handa 
Signed-off-by: Jeff Layton 
Signed-off-by: Steve French

cif: fix dead code

2014-04-17T04:08:57+00:00

This issue was found by Coverity (CID 1202536)

This proposes a fix for a statement that creates dead code.
The "rc < 0" statement is within code that is run
with "rc > 0".

It seems like "err < 0" was meant to be used here.
This way, the error code is returned by the function.

Signed-off-by: Michael Opdenacker 
Acked-by: Al Viro 
Signed-off-by: Steve French

cifs: fix error handling cifs_user_readv

2014-04-17T03:54:30+00:00

Coverity says:

*** CID 1202537:  Dereference after null check  (FORWARD_NULL)
/fs/cifs/file.c: 2873 in cifs_user_readv()
2867     		cur_len = min_t(const size_t, len - total_read, cifs_sb->rsize);
2868     		npages = DIV_ROUND_UP(cur_len, PAGE_SIZE);
2869
2870     		/* allocate a readdata struct */
2871     		rdata = cifs_readdata_alloc(npages,
2872     					    cifs_uncached_readv_complete);
>>>     CID 1202537:  Dereference after null check  (FORWARD_NULL)
>>>     Comparing "rdata" to null implies that "rdata" might be null.
2873     		if (!rdata) {
2874     			rc = -ENOMEM;
2875     			goto error;
2876     		}
2877
2878     		rc = cifs_read_allocate_pages(rdata, npages);

...when we "goto error", rc will be non-zero, and then we end up trying
to do a kref_put on the rdata (which is NULL). Fix this by replacing
the "goto error" with a "break".

Reported-by: 
Signed-off-by: Jeff Layton 
Signed-off-by: Steve French

fs: cifs: remove unused variable.

2014-04-16T18:51:46+00:00

In SMB2_set_compression(), the "res_key" variable is only initialized to NULL
and later kfreed. It is therefore useless and should be removed.

Found with the following semantic patch:


@@
identifier foo;
identifier f;
type T;
@@
* f(...) {
...
* T *foo = NULL;
... when forall
    when != foo
* kfree(foo);
...
}


Signed-off-by: Cyril Roelandt 
Signed-off-by: Steve French

Return correct error on query of xattr on file with empty xattrs

2014-04-16T18:51:46+00:00

xfstest 020 detected a problem with cifs xattr handling.  When a file
had an empty xattr list, we returned success (with an empty xattr value)
on query of particular xattrs rather than returning ENODATA.
This patch fixes it so that query of an xattr returns ENODATA when the
xattr list is empty for the file.

Signed-off-by: Steve French 
Reviewed-by: Jeff Layton

cifs: Wait for writebacks to complete before attempting write.

2014-04-16T18:51:46+00:00

Problem reported in Red Hat bz 1040329 for strict writes where we cache
only when we hold oplock and write direct to the server when we don't.

When we receive an oplock break, we first change the oplock value for
the inode in cifsInodeInfo->oplock to indicate that we no longer hold
the oplock before we enqueue a task to flush changes to the backing
device. Once we have completed flushing the changes, we return the
oplock to the server.

There are 2 ways here where we can have data corruption
1) While we flush changes to the backing device as part of the oplock
break, we can have processes write to the file. These writes check for
the oplock, find none and attempt to write directly to the server.
These direct writes made while we are flushing from cache could be
overwritten by data being flushed from the cache causing data
corruption.
2) While a thread runs in cifs_strict_writev, the machine could receive
and process an oplock break after the thread has checked the oplock and
found that it allows us to cache and before we have made changes to the
cache. In that case, we end up with a dirty page in cache when we
shouldn't have any. This will be flushed later and will overwrite all
subsequent writes to the part of the file represented by this page.

Before making any writes to the server, we need to confirm that we are
not in the process of flushing data to the server and if we are, we
should wait until the process is complete before we attempt the write.
We should also wait for existing writes to complete before we process
an oplock break request which changes oplock values.

We add a version specific  downgrade_oplock() operation to allow for
differences in the oplock values set for the different smb versions.

Cc: stable@vger.kernel.org
Signed-off-by: Sachin Prabhu 
Reviewed-by: Jeff Layton 
Reviewed-by: Pavel Shilovsky 
Signed-off-by: Steve French

cifs: Use min_t() when comparing "size_t" and "unsigned long"

2014-04-13T21:10:26+00:00

On 32 bit, size_t is "unsigned int", not "unsigned long", causing the
following warning when comparing with PAGE_SIZE, which is always "unsigned
long":

  fs/cifs/file.c: In function ‘cifs_readdata_to_iov’:
  fs/cifs/file.c:2757: warning: comparison of distinct pointer types lacks a cast

Introduced by commit 7f25bba819a3 ("cifs_iovec_read: keep iov_iter
between the calls of cifs_readdata_to_iov()"), which changed the
signedness of "remaining" and the code from min_t() to min().

Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2014-04-12T21:49:50+00:00

Pull vfs updates from Al Viro:
 "The first vfs pile, with deep apologies for being very late in this
  window.

  Assorted cleanups and fixes, plus a large preparatory part of iov_iter
  work.  There's a lot more of that, but it'll probably go into the next
  merge window - it *does* shape up nicely, removes a lot of
  boilerplate, gets rid of locking inconsistencie between aio_write and
  splice_write and I hope to get Kent's direct-io rewrite merged into
  the same queue, but some of the stuff after this point is having
  (mostly trivial) conflicts with the things already merged into
  mainline and with some I want more testing.

  This one passes LTP and xfstests without regressions, in addition to
  usual beating.  BTW, readahead02 in ltp syscalls testsuite has started
  giving failures since "mm/readahead.c: fix readahead failure for
  memoryless NUMA nodes and limit readahead pages" - might be a false
  positive, might be a real regression..."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
  missing bits of "splice: fix racy pipe->buffers uses"
  cifs: fix the race in cifs_writev()
  ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure
  kill generic_file_buffered_write()
  ocfs2_file_aio_write(): switch to generic_perform_write()
  ceph_aio_write(): switch to generic_perform_write()
  xfs_file_buffered_aio_write(): switch to generic_perform_write()
  export generic_perform_write(), start getting rid of generic_file_buffer_write()
  generic_file_direct_write(): get rid of ppos argument
  btrfs_file_aio_write(): get rid of ppos
  kill the 5th argument of generic_file_buffered_write()
  kill the 4th argument of __generic_file_aio_write()
  lustre: don't open-code kernel_recvmsg()
  ocfs2: don't open-code kernel_recvmsg()
  drbd: don't open-code kernel_recvmsg()
  constify blk_rq_map_user_iov() and friends
  lustre: switch to kernel_sendmsg()
  ocfs2: don't open-code kernel_sendmsg()
  take iov_iter stuff to mm/iov_iter.c
  process_vm_access: tidy up a bit
  ...

cifs: fix the race in cifs_writev()

2014-04-12T10:52:48+00:00

O_APPEND handling there hadn't been completely fixed by Pavel's
patch; it checks the right value, but it's racy - we can't really
do that until i_mutex has been taken.

Fix by switching to __generic_file_aio_write() (open-coding
generic_file_aio_write(), actually) and pulling mutex_lock() above
inode_size_read().

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro

mm: implement ->map_pages for page cache

2014-04-07T23:35:53+00:00

filemap_map_pages() is generic implementation of ->map_pages() for
filesystems who uses page cache.

It should be safe to use filemap_map_pages() for ->map_pages() if
filesystem use filemap_fault() for ->fault().

Signed-off-by: Kirill A. Shutemov 
Acked-by: Linus Torvalds 
Cc: Mel Gorman 
Cc: Rik van Riel 
Cc: Andi Kleen 
Cc: Matthew Wilcox 
Cc: Dave Hansen 
Cc: Alexander Viro 
Cc: Dave Chinner 
Cc: Ning Qu 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds