Pull vfs fixes from Al Viro: - backport-friendly part of lock_parent() race fix - a fix for an assumption in the heurisic used by path_connected() that is not true on NFS - livelock fixes for d_alloc_parallel() * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: Teach path_connected to handle nfs filesystems with multiple roots. fs: dcache: Use READ_ONCE when accessing i_dir_seq fs: dcache: Avoid livelock between d_alloc_parallel and __d_add lock_parent() needs to recheck if dentry got __dentry_kill'ed under it
On nfsv2 and nfsv3 the nfs server can export subsets of the same
filesystem and report the same filesystem identifier, so that the nfs
client can know they are the same filesystem. The subsets can be from
disjoint directory trees. The nfsv2 and nfsv3 filesystems provides no
way to find the common root of all directory trees exported form the
server with the same filesystem identifier.
The practical result is that in struct super s_root for nfs s_root is
not necessarily the root of the filesystem. The nfs mount code sets
s_root to the root of the first subset of the nfs filesystem that the
kernel mounts.
This effects the dcache invalidation code in generic_shutdown_super
currently called shrunk_dcache_for_umount and that code for years
has gone through an additional list of dentries that might be dentry
trees that need to be freed to accomodate nfs.
When I wrote path_connected I did not realize nfs was so special, and
it's hueristic for avoiding calling is_subdir can fail.
The practical case where this fails is when there is a move of a
directory from the subtree exposed by one nfs mount to the subtree
exposed by another nfs mount. This move can happen either locally or
remotely. With the remote case requiring that the move directory be cached
before the move and that after the move someone walks the path
to where the move directory now exists and in so doing causes the
already cached directory to be moved in the dcache through the magic
of d_splice_alias.
If someone whose working directory is in the move directory or a
subdirectory and now starts calling .. from the initial mount of nfs
(where s_root == mnt_root), then path_connected as a heuristic will
not bother with the is_subdir check. As s_root really is not the root
of the nfs filesystem this heuristic is wrong, and the path may
actually not be connected and path_connected can fail.
The is_subdir function might be cheap enough that we can call it
unconditionally. Verifying that will take some benchmarking and
the result may not be the same on all kernels this fix needs
to be backported to. So I am avoiding that for now.
Filesystems with snapshots such as nilfs and btrfs do something
similar. But as the directory tree of the snapshots are disjoint
from one another and from the main directory tree rename won't move
things between them and this problem will not occur.
Cc: stable@vger.kernel.org
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Fixes: 397d425dc26d ("vfs: Test for and handle paths that are unreachable from their mnt_root")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We do want to respect the FLUSH_SYNC argument to nfs_commit_inode() to
ensure that all outstanding COMMIT requests to the inode in question are
complete. Currently we may exit early from both nfs_commit_inode() and
nfs_write_inode() even if there are COMMIT requests in flight, or unstable
writes on the commit list.
In order to get the right semantics w.r.t. sync_inode(), we don't need
to have nfs_commit_inode() reset the inode dirty flags when called from
nfs_wb_page() and/or nfs_wb_all(). We just need to ensure that
nfs_write_inode() leaves them in the right state if there are outstanding
commits, or stable pages.
Reported-by: Scott Mayhew <smayhew@redhat.com>
Fixes: dc4fd9ab01ab ("nfs: don't wait on commit in nfs_commit_inode()...")
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Ensure that we hold a reference to the layout header when processing the pNFS return-on-close so that the refcount value does not inadvertently go to zero. Reported-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Cc: stable@vger.kernel.org # v4.10+ Tested-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
The start offset needs to be of type loff_t.
Fixed: 5fadeb47dcc5c ("nfs: count DIO good bytes correctly with mirroring")
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
The structure nlmclnt_fl_close_lock_ops s local to the source and does not need to be in global scope, so make it static. Cleans up sparse warning: fs/nfs/nfs3proc.c:876:33: warning: symbol 'nlmclnt_fl_close_lock_ops' was not declared. Should it be static? Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
nfs4_update_server unconditionally releases the nfs_client for the
source server. If migration fails, this can cause the source server's
nfs_client struct to be left with a low reference count, resulting in
use-after-free. Also, adjust reference count handling for ELOOP.
NFS: state manager: migration failed on NFSv4 server nfsvmu10 with error 6
WARNING: CPU: 16 PID: 17960 at fs/nfs/client.c:281 nfs_put_client+0xfa/0x110 [nfs]()
nfs_put_client+0xfa/0x110 [nfs]
nfs4_run_state_manager+0x30/0x40 [nfsv4]
kthread+0xd8/0xf0
BUG: unable to handle kernel NULL pointer dereference at 00000000000002a8
nfs4_xdr_enc_write+0x6b/0x160 [nfsv4]
rpcauth_wrap_req+0xac/0xf0 [sunrpc]
call_transmit+0x18c/0x2c0 [sunrpc]
__rpc_execute+0xa6/0x490 [sunrpc]
rpc_async_schedule+0x15/0x20 [sunrpc]
process_one_work+0x160/0x470
worker_thread+0x112/0x540
? rescuer_thread+0x3f0/0x3f0
kthread+0xd8/0xf0
This bug was introduced by 32e62b7c ("NFS: Add nfs4_update_server"),
but the fix applies cleanly to 52442f9b ("NFS4: Avoid migration loops")
Reported-by: Helen Chao <helen.chao@oracle.com>
Fixes: 52442f9b11b7 ("NFS4: Avoid migration loops")
Signed-off-by: Bill Baker <bill.baker@oracle.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Passing a pointer to a unsigned integer to test_bit() is broken. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
The function inode_cmp_iversion{+raw} is counter-intuitive, because it
returns true when the counters are different and false when these are equal.
Rename it to inode_eq_iversion{+raw}, which will returns true when
the counters are equal and false otherwise.
Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Pull misc vfs updates from Al Viro: "All kinds of misc stuff, without any unifying topic, from various people. Neil's d_anon patch, several bugfixes, introduction of kvmalloc analogue of kmemdup_user(), extending bitfield.h to deal with fixed-endians, assorted cleanups all over the place..." * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits) alpha: osf_sys.c: use timespec64 where appropriate alpha: osf_sys.c: fix put_tv32 regression jffs2: Fix use-after-free bug in jffs2_iget()'s error handling path dcache: delete unused d_hash_mask dcache: subtract d_hash_shift from 32 in advance fs/buffer.c: fold init_buffer() into init_page_buffers() fs: fold __inode_permission() into inode_permission() fs: add RWF_APPEND sctp: use vmemdup_user() rather than badly open-coding memdup_user() snd_ctl_elem_init_enum_names(): switch to vmemdup_user() replace_user_tlv(): switch to vmemdup_user() new primitive: vmemdup_user() memdup_user(): switch to GFP_USER eventfd: fold eventfd_ctx_get() into eventfd_ctx_fileget() eventfd: fold eventfd_ctx_read() into eventfd_read() eventfd: convert to use anon_inode_getfd() nfs4file: get rid of pointless include of btrfs.h uvc_v4l2: clean copyin/copyout up vme_user: don't use __copy_..._user() usx2y: don't bother with memdup_user() for 16-byte structure ...