linux.git/fs/nfs/write.c, branch v3.16

NFS: Remove 2 unused variables

2014-07-12T21:35:57+00:00

Cc: Weston Andros Adamson 
Signed-off-by: Trond Myklebust

nfs: handle multiple reqs in nfs_wb_page_cancel

2014-07-12T21:35:47+00:00

Use nfs_lock_and_join_requests to merge all subrequests into the head request -
this cancels and dereferences all subrequests.

Signed-off-by: Weston Andros Adamson 
Signed-off-by: Trond Myklebust

nfs: handle multiple reqs in nfs_page_async_flush

2014-07-12T21:35:46+00:00

Change nfs_find_and_lock_request so nfs_page_async_flush can handle multiple
requests in a page. There is only one request for a page the first time
nfs_page_async_flush is called, but if a write or commit fails, async_flush
is called again and there may be multiple requests associated with the page.
The solution is to merge all the requests in a page group into a single
request before calling nfs_pageio_add_request.

Rename nfs_find_and_lock_request to nfs_lock_and_join_requests and
change it to first lock all requests for the page, then cancel and merge
all subrequests into the head request.

Signed-off-by: Weston Andros Adamson 
Signed-off-by: Trond Myklebust

nfs: change find_request to find_head_request

2014-07-12T20:51:41+00:00

nfs_page_find_request_locked* should find the head request for that page.
Rename the functions and add comments to make this clear, and fix a bug
that could return a subrequest when page_private isn't set on the page.

Signed-off-by: Weston Andros Adamson 
Signed-off-by: Trond Myklebust

nfs: mark nfs_page reqs with flag for extra ref

2014-07-12T20:51:41+00:00

Change the use of PG_INODE_REF - set it when taking extra reference on
subrequests and take care to only release once for each request.

Signed-off-by: Weston Andros Adamson 
Signed-off-by: Trond Myklebust

nfs: Fix cache_validity check in nfs_write_pageuptodate()

2014-06-24T22:46:56+00:00

NFS_INO_INVALID_DATA cannot be ignored, even if we have a delegation.

We're still having some problems with data corruption when multiple
clients are appending to a file and those clients are being granted
write delegations on open.

To reproduce:

Client A:
vi /mnt/`hostname -s`
while :; do echo "XXXXXXXXXXXXXXX" >>/mnt/file; sleep $(( $RANDOM % 5 )); done

Client B:
vi /mnt/`hostname -s`
while :; do echo "YYYYYYYYYYYYYYY" >>/mnt/file; sleep $(( $RANDOM % 5 )); done

What's happening is that in nfs_update_inode() we're recognizing that
the file size has changed and we're setting NFS_INO_INVALID_DATA
accordingly, but then we ignore the cache_validity flags in
nfs_write_pageuptodate() because we have a delegation.  As a result,
in nfs_updatepage() we're extending the write to cover the full page
even though we've not read in the data to begin with.

Signed-off-by: Scott Mayhew 
Cc:  # v3.11+
Signed-off-by: Trond Myklebust

Merge tag 'nfs-for-3.16-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

2014-06-10T22:02:42+00:00

Pull NFS client updates from Trond Myklebust:
 "Highlights include:

   - massive cleanup of the NFS read/write code by Anna and Dros
   - support multiple NFS read/write requests per page in order to deal
     with non-page aligned pNFS striping.  Also cleans up the r/wsize <
     page size code nicely.
   - stable fix for ensuring inode is declared uptodate only after all
     the attributes have been checked.
   - stable fix for a kernel Oops when remounting
   - NFS over RDMA client fixes
   - move the pNFS files layout driver into its own subdirectory"

* tag 'nfs-for-3.16-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (79 commits)
  NFS: populate ->net in mount data when remounting
  pnfs: fix lockup caused by pnfs_generic_pg_test
  NFSv4.1: Fix typo in dprintk
  NFSv4.1: Comment is now wrong and redundant to code
  NFS: Use raw_write_seqcount_begin/end int nfs4_reclaim_open_state
  xprtrdma: Disconnect on registration failure
  xprtrdma: Remove BUG_ON() call sites
  xprtrdma: Avoid deadlock when credit window is reset
  SUNRPC: Move congestion window constants to header file
  xprtrdma: Reset connection timeout after successful reconnect
  xprtrdma: Use macros for reconnection timeout constants
  xprtrdma: Allocate missing pagelist
  xprtrdma: Remove Tavor MTU setting
  xprtrdma: Ensure ia->ri_id->qp is not NULL when reconnecting
  xprtrdma: Reduce the number of hardway buffer allocations
  xprtrdma: Limit work done by completion handler
  xprtrmda: Reduce calls to ib_poll_cq() in completion handlers
  xprtrmda: Reduce lock contention in completion handlers
  xprtrdma: Split the completion queue
  xprtrdma: Make rpcrdma_ep_destroy() return void
  ...

nfs: page group support in nfs_mark_uptodate

2014-05-29T15:11:46+00:00

Change how nfs_mark_uptodate checks to see if writes cover a whole page.

This patch should have no effect yet since all page groups currently
have one request, but will come into play when pg_test functions are
modified to split pages into sub-page regions.

Signed-off-by: Weston Andros Adamson 
Signed-off-by: Trond Myklebust

nfs: page group syncing in write path

2014-05-29T15:11:45+00:00

Operations that modify state for a whole page must be syncronized across
all requests within a page group. In the write path, this is calling
end_page_writeback and removing the head request from an inode.
Both of these operations should not be called until all requests
in a page group have reached the point where they would call them.

This patch should have no effect yet since all page groups currently
have one request, but will come into play when pg_test functions are
modified to split pages into sub-page regions.

Signed-off-by: Weston Andros Adamson 
Signed-off-by: Trond Myklebust

nfs: add support for multiple nfs reqs per page

2014-05-29T15:11:44+00:00

Add "page groups" - a circular list of nfs requests (struct nfs_page)
that all reference the same page. This gives nfs read and write paths
the ability to account for sub-page regions independently.  This
somewhat follows the design of struct buffer_head's sub-page
accounting.

Only "head" requests are ever added/removed from the inode list in
the buffered write path. "head" and "sub" requests are treated the
same through the read path and the rest of the write/commit path.
Requests are given an extra reference across the life of the list.

Page groups are never rejoined after being split. If the read/write
request fails and the client falls back to another path (ie revert
to MDS in PNFS case), the already split requests are pushed through
the recoalescing code again, which may split them further and then
coalesce them into properly sized requests on the wire. Fragmentation
shouldn't be a problem with the current design, because we flush all
requests in page group when a non-contiguous request is added, so
the only time resplitting should occur is on a resend of a read or
write.

This patch lays the groundwork for sub-page splitting, but does not
actually do any splitting. For now all page groups have one request
as pg_test functions don't yet split pages. There are several related
patches that are needed support multiple requests per page group.

Signed-off-by: Weston Andros Adamson 
Signed-off-by: Trond Myklebust