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>
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>
This patch inverts the callback hierarchy for NFS write calls.
Instead of having the NFSv2/v3/v4-specific code set up the RPC callback
ops, we allow the original caller to do so. This allows for more
flexibility w.r.t. how to set up and tear down the nfs_write_data
structure while still allowing the NFSv3/v4 code to perform error
handling.
The greater flexibility is needed by the asynchronous O_DIRECT code, which
wants to be able to hold on to the original nfs_write_data structures after
the WRITE RPC call has completed in order to be able to replay them if the
COMMIT call determines that the server has rebooted.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Invoke the byte and event counter macros where we want to count bytes and
events.
Clean-up: fix a possible NULL dereference in nfs_lock, and simplify
nfs_file_open.
Test-plan:
fsx and iozone on UP and SMP systems, with and without pre-emption. Watch
for memory overwrite bugs, and performance loss (significantly more CPU
required per op).
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
this converts fs/nfs to kzalloc() usage.
compile tested with make allyesconfig
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
I've been reading through fs/nfs/write.c trying to track down a bug
that seems to be related to pages loosing a refcount and getting
freed too early (you interested in detail??) and I spotted a little
bug which the following patch should fix.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The SuS states that a call to write() will cause mtime to be updated on
the file. In order to satisfy that requirement, we need to flush out
any cached writes in nfs_getattr().
Speed things up slightly by not committing the writes.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Most NFS server implementations allow up to 64KB reads and writes on the
wire. The Solaris NFS server allows up to a megabyte, for instance.
Now the Linux NFS client supports transfer sizes up to 1MB, too. This will
help reduce protocol and context switch overhead on read/write intensive NFS
workloads, and support larger atomic read and write operations on servers
that support them.
Test-plan:
Connectathon and iozone on mount point with wsize=rsize>32768 over TCP.
Tests with NFS over UDP to verify the maximum RPC payload size cap.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Shrink the RPC task structure. Instead of storing separate pointers
for task->tk_exit and task->tk_release, put them in a structure.
Also pass the user data pointer as a parameter instead of passing it via
task->tk_calldata. This enables us to nest callbacks.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Ensure that we always initiate flushing of data before we exit
a single-page ->writepage() call.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Ensure that we use set_page_writeback() in the appropriate places
to help the VM in keeping its page radix_tree in sync.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Fix some dprintk's so that NLM, NFS client, and RPC client compile
cleanly if CONFIG_SYSCTL is disabled.
Test plan:
Compile kernel with CONFIG_NFS enabled and CONFIG_SYSCTL disabled.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
RFC 3530 states that for OPEN_DOWNGRADE "The share_access and share_deny
bits specified must be exactly equal to the union of the share_access and
share_deny bits specified for some subset of the OPENs in effect for
current openowner on the current file.
Setattr is currently violating the NFSv4 rules for OPEN_DOWNGRADE in that
it may cause a downgrade from OPEN4_SHARE_ACCESS_BOTH to
OPEN4_SHARE_ACCESS_WRITE despite the fact that there exists no open file
with O_WRONLY access mode.
Fix the problem by replacing nfs4_find_state() with a modified version of
nfs_find_open_context().
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Basically copies the VFS's method for tracking writebacks and applies
it to the struct nfs_page.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Instead of looking at whether or not the file is open for writes before
we accept to update the length using the server value, we should rather
be looking at whether or not we are currently caching any writes.
Failure to do so means in particular that we're not updating the file
length correctly after obtaining a POSIX or BSD lock.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Trond Myklebust