Kudos to Neil Brown for spotting the problem:
"in nfs_sync_inode, there is effectively the sequence:
nfs_wait_on_requests
nfs_flush_inode
nfs_commit_inode
This seems a bit racy to me as if the only requests are on the
->commit list, and nfs_commit_inode is called separately after
nfs_wait_on_requests completes, and before nfs_commit_inode start
(say: by nfs_write_inode) then none of these function will return
>0, yet there will be some pending request that aren't waited for."
The solution is to search for requests to wait upon, search for dirty
requests, and search for uncommitted requests while holding the
nfsi->req_lock
The patch also cleans up nfs_sync_inode(), getting rid of the redundant
FLUSH_WAIT flag. It turns out that we were always setting it.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We don't need to set PG_private for readahead pages, since they never get
unlocked while I/O is in progress. However there is a small race in
nfs_readpage_release() whereby the page may be unlocked, and have
PG_private set.
Fix is to have PG_private set only for the case of writes...
Also fix a bug in nfs_clear_page_writeback(): Don't attempt to clear the
radix_tree tag if we've already deleted the radix tree entry.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the callback daemon is signalled, but is unable to exit because it still
has users, then we need to flush signals. If not, then svc_recv() can
never sleep, and so we hang.
If we flush signals, then we also have to be prepared to resend them when
we want the thread to exit.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Currently it returns NULL, which usually gets interpreted as ENOMEM. In
fact it can mean a host of issues.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The mount statistics patches introduced a call to nfs_free_iostats that is
not only redundant, but actually causes an oops.
Also fix a memory leak due to the lack of a call to nfs_free_iostats on
unmount.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The struct file_lock does not carry a properly initialised lock,
so don't copy it as if it were.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Now that we have aio writes, it is possible for dreq->outstanding to be
zero, but for the I/O not to have completed. Convert struct nfs_direct_req
to use a completion to signal when the I/O is done.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Introduced by NFS aio+dio patches.
Test plan:
Compile kernel with CONFIG_NFS enabled on 64-bit hardware.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Introduced by NFS metrics patch.
Test plan:
Compile kernel with CONFIG_NFS enabled on a 64-bit platform.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The patch "stop abusing file_lock_list introduces a couple of bugs since
the locks may be copied and need to be removed from the lists when they are
destroyed.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Currently lockd directly access the file_lock_list from fs/locks.c.
It does so to mark locks granted or reclaimable. This is very
suboptimal, because a) lockd needs to poke into locks.c internals, and
b) it needs to iterate over all locks in the system for marking locks
granted or reclaimable.
This patch adds lists for granted and reclaimable locks to the nlm_host
structure instead, and adds locks to those.
nlmclnt_lock:
now adds the lock to h_granted instead of setting the
NFS_LCK_GRANTED, still O(1)
nlmclnt_mark_reclaim:
goes away completely, replaced by a list_splice_init.
Complexity reduced from O(locks in the system) to O(1)
reclaimer:
iterates over h_reclaim now, complexity reduced from
O(locks in the system) to O(locks per nlm_host)
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
When doing NLM_GRANTED requests, lockd may end up blocking if we use
rpc_create_client() due to the synchronous call to rpc_ping(). Instead, use
rpc_new_client().
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Currently it uses nlmclnt_lookup_host(), which puts the resulting host
structure on a different list.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The caller of posix_test_lock() should never need to look at the lock
private data, so do not copy that information. This also means that there
is no need to call the fl_release_private methods.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The struct nfs_direct_req currently keeps a pointer to the file descriptor
without referencing it. This may cause problems if the parent process is
killed.
The nfs_open_context should normally have all the information that we're
currently using the filp for, and unlike fput(), is safe to release from
an rpciod process context.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Currently NFS O_DIRECT writes use FILE_SYNC so that a COMMIT is not
necessary. This simplifies the internal logic, but this could be a
difficult workload for some servers.
Instead, let's send UNSTABLE writes, and after they all complete, send a
COMMIT for the dirty range. After the COMMIT returns successfully, then do
the wake_up or fire off aio_complete().
Test plan:
Async direct I/O tests against Solaris (or any server that requires
committed unstable writes). Reboot server during test.
Based on an earlier patch by Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
^C against "iozone -I" is hitting the assertion in nfs_clear_inode().
Test plan:
"iozone -i0 -I -a -c" against a slow server, then control C. This should
not cause an oops.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Three atomic_t variables cause a lot of bus locking. Because they are all
used in the same places in the code, just use a single spin lock.
Now that the atomic_t variables are gone, we can remove the request size
limitation since the code no longer depends on the limited width of atomic_t
on some platforms.
Test plan:
Compile with CONFIG_NFS and CONFIG_NFS_DIRECTIO enabled. Millions of fsx
operations, iozone, OraSim.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Clean up tab damage and comments. Replace "file_offset" with more commonly
used "pos".
Test plan:
Compile with CONFIG_NFS and CONFIG_NFS_DIRECTIO enabled.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
For async iocb's, the NFS direct write path now returns EIOCBQUEUED,
and calls aio_complete when all the requested writes are finished. The
synchronous part of the NFS direct write path behaves exactly as it
was before.
Shared mapped NFS files will have some coherency difficulties when
accessed concurrently with aio+dio. Will need to explore how this
is handled in the local file system case.
Test plan:
aio-stress with "-O". OraSim.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Pass the iocb argument all the way down to the direct write request
scheduler, and make it available in nfs_direct_write_result.
Test plan:
Compile the kernel with CONFIG_NFS and CONFIG_NFS_DIRECTIO enabled.
Millions of fsx-odirect ops. OraSim.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Eliminate the persistent use of automatic storage in all parts of the
NFS client's direct write path to pave the way for introducing support
for aio against files opened with the O_DIRECT flag.
Test plan:
Compile the kernel with CONFIG_NFS and CONFIG_NFS_DIRECTIO enabled.
Millions of fsx-odirect ops. OraSim.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Duplicate infrastructure from direct read path that will allow write
path to generate multiple write requests concurrently. This will
enable us to add support for aio in this path.
Temporarily we will lose the ability to do UNSTABLE writes followed by
a COMMIT in the direct write path. However, all applications I am
aware of that use NFS O_DIRECT currently write in relatively small
chunks, so this should not be inconvenient in any way.
Test plan:
Millions of fsx-odirect ops. OraSim.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Factor out the common piece of completing an NFS direct I/O request.
Test plan:
Compile kernel with CONFIG_NFS and CONFIG_NFS_DIRECTIO enabled.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Factor out a small common piece of the path that allocate nfs_direct_req
structures.
Test plan:
Compile kernel with CONFIG_NFS and CONFIG_NFS_DIRECTIO enabled.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We're about to add asynchrony to the NFS direct write path. Begin by
abstracting out the common pieces in the read path.
The first piece is nfs_direct_read_wait, which works the same whether the
process is waiting for a read or a write.
Test plan:
Compile kernel with CONFIG_NFS and CONFIG_NFS_DIRECTIO enabled.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
For async iocb's, the NFS direct read path should return EIOCBQUEUED and
call aio_complete when all the requested reads are finished. The
synchronous part of the NFS direct read path behaves exactly as it was
before.
Test plan:
aio-stress with "-O". OraSim.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Pass the iocb argument all the way down to the direct read request
scheduler, and make it available in nfs_direct_read_result.
Test plan:
Compile the kernel with CONFIG_NFS and CONFIG_NFS_DIRECTIO enabled.
Millions of fsx-odirect ops. OraSim.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Eliminate the persistent use of automatic storage in all parts of the NFS
client's direct read path to pave the way for introducing support for aio
against files opened with the O_DIRECT flag.
Test plan:
Compile the kernel with CONFIG_NFS and CONFIG_NFS_DIRECTIO enabled.
Millions of fsx-odirect ops. OraSim.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
size_t is used for holding byte counts, so use it for variables storing rsize.
Note that the write path will be updated as we add support for async
O_DIRECT writes.
Test plan:
Need to verify that existing comparisons against new size_t variables behave
correctly.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Update to latest coding style standards. Remove block comments on
statically defined functions, and place function definitions all on
one line.
Test plan:
Compile kernel with CONFIG_NFS and CONFIG_NFS_DIRECTIO.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
