linux-toradex.git/include/linux/nfs_fs.h, branch v3.12.29

NFS: fix the handling of NFS_INO_INVALID_DATA flag in nfs_revalidate_mapping

2014-04-03T08:32:17+00:00

commit d529ef83c355f97027ff85298a9709fe06216a66 upstream.

There is a possible race in how the nfs_invalidate_mapping function is
handled.  Currently, we go and invalidate the pages in the file and then
clear NFS_INO_INVALID_DATA.

The problem is that it's possible for a stale page to creep into the
mapping after the page was invalidated (i.e., via readahead). If another
writer comes along and sets the flag after that happens but before
invalidate_inode_pages2 returns then we could clear the flag
without the cache having been properly invalidated.

So, we must clear the flag first and then invalidate the pages. Doing
this however, opens another race:

It's possible to have two concurrent read() calls that end up in
nfs_revalidate_mapping at the same time. The first one clears the
NFS_INO_INVALID_DATA flag and then goes to call nfs_invalidate_mapping.

Just before calling that though, the other task races in, checks the
flag and finds it cleared. At that point, it trusts that the mapping is
good and gets the lock on the page, allowing the read() to be satisfied
from the cache even though the data is no longer valid.

These effects are easily manifested by running diotest3 from the LTP
test suite on NFS. That program does a series of DIO writes and buffered
reads. The operations are serialized and page-aligned but the existing
code fails the test since it occasionally allows a read to come out of
the cache incorrectly. While mixing direct and buffered I/O isn't
recommended, I believe it's possible to hit this in other ways that just
use buffered I/O, though that situation is much harder to reproduce.

The problem is that the checking/clearing of that flag and the
invalidation of the mapping really need to be atomic. Fix this by
serializing concurrent invalidations with a bitlock.

At the same time, we also need to allow other places that check
NFS_INO_INVALID_DATA to check whether we might be in the middle of
invalidating the file, so fix up a couple of places that do that
to look for the new NFS_INO_INVALIDATING flag.

Doing this requires us to be careful not to set the bitlock
unnecessarily, so this code only does that if it believes it will
be doing an invalidation.

Signed-off-by: Jeff Layton 
Signed-off-by: Trond Myklebust 
Signed-off-by: Jiri Slaby

NFS: Ensure that rmdir() waits for sillyrenames to complete

2013-09-03T19:26:29+00:00

If an NFS client does

	mkdir("dir");
	fd = open("dir/file");
	unlink("dir/file");
	close(fd);
	rmdir("dir");

then the asynchronous nature of the sillyrename operation means that
we can end up getting EBUSY for the rmdir() in the above test. Fix
that by ensuring that we wait for any in-progress sillyrenames
before sending the rmdir() to the server.

Signed-off-by: Trond Myklebust

NFS: Make nfs_attribute_cache_expired() non-static

2013-07-09T21:17:07+00:00

NFS: Make nfs_attribute_cache_expired() non-static so we can call it from
nfs_readdir().

Signed-off-by: Scott Mayhew 
Signed-off-by: Trond Myklebust

Merge branch 'labeled-nfs' into linux-next

2013-06-28T20:29:51+00:00

* labeled-nfs:
  NFS: Apply v4.1 capabilities to v4.2
  NFS: Add in v4.2 callback operation
  NFS: Make callbacks minor version generic
  Kconfig: Add Kconfig entry for Labeled NFS V4 client
  NFS: Extend NFS xattr handlers to accept the security namespace
  NFS: Client implementation of Labeled-NFS
  NFS: Add label lifecycle management
  NFS:Add labels to client function prototypes
  NFSv4: Extend fattr bitmaps to support all 3 words
  NFSv4: Introduce new label structure
  NFSv4: Add label recommended attribute and NFSv4 flags
  NFSv4.2: Added NFS v4.2 support to the NFS client
  SELinux: Add new labeling type native labels
  LSM: Add flags field to security_sb_set_mnt_opts for in kernel mount data.
  Security: Add Hook to test if the particular xattr is part of a MAC model.
  Security: Add hook to calculate context based on a negative dentry.
  NFS: Add NFSv4.2 protocol constants

Conflicts:
	fs/nfs/nfs4proc.c

NFS: Client implementation of Labeled-NFS

2013-06-08T20:20:16+00:00

This patch implements the client transport and handling support for labeled
NFS. The patch adds two functions to encode and decode the security label
recommended attribute which makes use of the LSM hooks added earlier. It also
adds code to grab the label from the file attribute structures and encode the
label to be sent back to the server.

Acked-by: James Morris 
Signed-off-by: Matthew N. Dodd 
Signed-off-by: Miguel Rodel Felipe 
Signed-off-by: Phua Eu Gene 
Signed-off-by: Khin Mi Mi Aung 
Signed-off-by: Steve Dickson 
Signed-off-by: Trond Myklebust

NFS:Add labels to client function prototypes

2013-06-08T20:20:15+00:00

After looking at all of the nfsv4 operations the label structure has been added
to the prototypes of the functions which can transmit label data.

Signed-off-by: Matthew N. Dodd 
Signed-off-by: Miguel Rodel Felipe 
Signed-off-by: Phua Eu Gene 
Signed-off-by: Khin Mi Mi Aung 
Signed-off-by: Steve Dickson 
Signed-off-by: Trond Myklebust

NFSv4: Introduce new label structure

2013-06-08T20:20:14+00:00

In order to mimic the way that NFSv4 ACLs are implemented we have created a
structure to be used to pass label data up and down the call chain. This patch
adds the new structure and new members to the required NFSv4 call structures.

Signed-off-by: Matthew N. Dodd 
Signed-off-by: Miguel Rodel Felipe 
Signed-off-by: Phua Eu Gene 
Signed-off-by: Khin Mi Mi Aung 
Signed-off-by: Steve Dickson 
Signed-off-by: Trond Myklebust

NFSv4: Close another NFSv4 recovery race

2013-06-06T20:24:44+00:00

State recovery currently relies on being able to find a valid
nfs_open_context in the inode->open_files list.
We therefore need to put the nfs_open_context on the list while
we're still protected by the sp->so_reclaim_seqcount in order
to avoid reboot races.

Signed-off-by: Trond Myklebust

NFS: Add functionality to allow waiting on all outstanding reads to complete

2013-04-09T02:12:33+00:00

This will later allow NFS locking code to wait for readahead to complete
before releasing byte range locks.

Signed-off-by: Trond Myklebust

NFS: Don't accept more reads/writes if the open context recovery failed

2013-03-25T16:04:10+00:00

If the state recovery failed, we want to ensure that the application
doesn't try to use the same file descriptor for more reads or writes.

Signed-off-by: Trond Myklebust