linux.git/fs/nfs, branch v5.7

NFSv3: fix rpc receive buffer size for MOUNT call

2020-05-14T22:42:44+00:00

Prior to commit e3d3ab64dd66 ("SUNRPC: Use au_rslack when
computing reply buffer size"), there was enough slack in the reply
buffer to commodate filehandles of size 60bytes. However, the real
problem was that the reply buffer size for the MOUNT operation was
not correctly calculated. Received buffer size used the filehandle
size for NFSv2 (32bytes) which is much smaller than the allowed
filehandle size for the v3 mounts.

Fix the reply buffer size (decode arguments size) for the MNT command.

Fixes: 2c94b8eca1a2 ("SUNRPC: Use au_rslack when computing reply buffer size")
Signed-off-by: Olga Kornievskaia 
Signed-off-by: Trond Myklebust

NFS/pnfs: Don't use RPC_TASK_CRED_NOREF with pnfs

2020-05-13T13:55:36+00:00

When we're doing pnfs then the credential being used for the RPC call
is not necessarily the same as the one used in the open context, so
don't use RPC_TASK_CRED_NOREF.

Fixes: 612965072020 ("NFSv4: Avoid referencing the cred unnecessarily during NFSv4 I/O")
Signed-off-by: Trond Myklebust

NFS: Don't use RPC_TASK_CRED_NOREF with delegreturn

2020-05-11T18:06:51+00:00

We are not guaranteed that the credential will remain pinned.

Fixes: 612965072020 ("NFSv4: Avoid referencing the cred unnecessarily during NFSv4 I/O")
Signed-off-by: Trond Myklebust

Merge tag 'fscache-fixes-20200508-2' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

2020-05-11T18:06:50+00:00

 (1) The reorganisation of bmap() use accidentally caused the return value
     of cachefiles_read_or_alloc_pages() to get corrupted.

 (2) The NFS superblock index key accidentally got changed to include a
     number of kernel pointers - meaning that the key isn't matchable after
     a reboot.

 (3) A redundant check in nfs_fscache_get_super_cookie().

 (4) The NFS change_attr sometimes set in the auxiliary data for the
     caching of an file and sometimes not, which causes the cache to get
     discarded when it shouldn't.

 (5) There's a race between cachefiles_read_waiter() and
     cachefiles_read_copier() that causes an occasional assertion failure.

nfs: fix NULL deference in nfs4_get_valid_delegation

2020-05-11T18:05:58+00:00

We add the new state to the nfsi->open_states list, making it
potentially visible to other threads, before we've finished initializing
it.

That wasn't a problem when all the readers were also taking the i_lock
(as we do here), but since we switched to RCU, there's now a possibility
that a reader could see the partially initialized state.

Symptoms observed were a crash when another thread called
nfs4_get_valid_delegation() on a NULL inode, resulting in an oops like:

	BUG: unable to handle page fault for address: ffffffffffffffb0 ...
	RIP: 0010:nfs4_get_valid_delegation+0x6/0x30 [nfsv4] ...
	Call Trace:
	 nfs4_open_prepare+0x80/0x1c0 [nfsv4]
	 __rpc_execute+0x75/0x390 [sunrpc]
	 ? finish_task_switch+0x75/0x260
	 rpc_async_schedule+0x29/0x40 [sunrpc]
	 process_one_work+0x1ad/0x370
	 worker_thread+0x30/0x390
	 ? create_worker+0x1a0/0x1a0
	 kthread+0x10c/0x130
	 ? kthread_park+0x80/0x80
	 ret_from_fork+0x22/0x30

Fixes: 9ae075fdd190 "NFSv4: Convert open state lookup to use RCU"
Reviewed-by: Seiichi Ikarashi 
Tested-by: Daisuke Matsuda 
Tested-by: Masayoshi Mizuma 
Signed-off-by: J. Bruce Fields 
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: Trond Myklebust

NFSv4: Fix fscache cookie aux_data to ensure change_attr is included

2020-05-08T21:20:24+00:00

Commit 402cb8dda949 ("fscache: Attach the index key and aux data to
the cookie") added the aux_data and aux_data_len to parameters to
fscache_acquire_cookie(), and updated the callers in the NFS client.
In the process it modified the aux_data to include the change_attr,
but missed adding change_attr to a couple places where aux_data was
used.  Specifically, when opening a file and the change_attr is not
added, the following attempt to lookup an object will fail inside
cachefiles_check_object_xattr() = -116 due to
nfs_fscache_inode_check_aux() failing memcmp on auxdata and returning
FSCACHE_CHECKAUX_OBSOLETE.

Fix this by adding nfs_fscache_update_auxdata() to set the auxdata
from all relevant fields in the inode, including the change_attr.

Fixes: 402cb8dda949 ("fscache: Attach the index key and aux data to the cookie")
Signed-off-by: Dave Wysochanski 
Signed-off-by: David Howells

NFS: Fix fscache super_cookie allocation

2020-05-08T21:20:24+00:00

Commit f2aedb713c28 ("NFS: Add fs_context support.") reworked
NFS mount code paths for fs_context support which included
super_block initialization.  In the process there was an extra
return left in the code and so we never call
nfs_fscache_get_super_cookie even if 'fsc' is given on as mount
option.  In addition, there is an extra check inside
nfs_fscache_get_super_cookie for the NFS_OPTION_FSCACHE which
is unnecessary since the only caller nfs_get_cache_cookie
checks this flag.

Fixes: f2aedb713c28 ("NFS: Add fs_context support.")
Signed-off-by: Dave Wysochanski 
Signed-off-by: David Howells

NFS: Fix fscache super_cookie index_key from changing after umount

2020-05-08T21:20:24+00:00

Commit 402cb8dda949 ("fscache: Attach the index key and aux data to
the cookie") added the index_key and index_key_len parameters to
fscache_acquire_cookie(), and updated the callers in the NFS client.
One of the callers was inside nfs_fscache_get_super_cookie()
and was changed to use the full struct nfs_fscache_key as the
index_key.  However, a couple members of this structure contain
pointers and thus will change each time the same NFS share is
remounted.  Since index_key is used for fscache_cookie->key_hash
and this subsequently is used to compare cookies, the effectiveness
of fscache with NFS is reduced to the point at which a umount
occurs.   Any subsequent remount of the same share will cause a
unique NFS super_block index_key and key_hash to be generated for
the same data, rendering any prior fscache data unable to be
found.  A simple reproducer demonstrates the problem.

1. Mount share with 'fsc', create a file, drop page cache
systemctl start cachefilesd
mount -o vers=3,fsc 127.0.0.1:/export /mnt
dd if=/dev/zero of=/mnt/file1.bin bs=4096 count=1
echo 3 > /proc/sys/vm/drop_caches

2. Read file into page cache and fscache, then unmount
dd if=/mnt/file1.bin of=/dev/null bs=4096 count=1
umount /mnt

3. Remount and re-read which should come from fscache
mount -o vers=3,fsc 127.0.0.1:/export /mnt
echo 3 > /proc/sys/vm/drop_caches
dd if=/mnt/file1.bin of=/dev/null bs=4096 count=1

4. Check for READ ops in mountstats - there should be none
grep READ: /proc/self/mountstats

Looking at the history and the removed function, nfs_super_get_key(),
we should only use nfs_fscache_key.key plus any uniquifier, for
the fscache index_key.

Fixes: 402cb8dda949 ("fscache: Attach the index key and aux data to the cookie")
Signed-off-by: Dave Wysochanski 
Signed-off-by: David Howells

NFS: Fix a race in __nfs_list_for_each_server()

2020-04-30T19:08:26+00:00

The struct nfs_server gets put on the cl_superblocks list before
the server->super field has been initialised, in which case the
call to nfs_sb_active() will Oops. Add a check to ensure that
we skip such a list entry.

Fixes: 3c9e502b59fb ("NFS: Add a helper nfs_client_for_each_server()")
Signed-off-by: Trond Myklebust

NFSv4.1: fix handling of backchannel binding in BIND_CONN_TO_SESSION

2020-04-28T19:58:38+00:00

Currently, if the client sends BIND_CONN_TO_SESSION with
NFS4_CDFC4_FORE_OR_BOTH but only gets NFS4_CDFS4_FORE back it ignores
that it wasn't able to enable a backchannel.

To make sure, the client sends BIND_CONN_TO_SESSION as the first
operation on the connections (ie., no other session compounds haven't
been sent before), and if the client's request to bind the backchannel
is not satisfied, then reset the connection and retry.

Cc: stable@vger.kernel.org
Signed-off-by: Olga Kornievskaia 
Signed-off-by: Trond Myklebust