linux-stable.git/fs/nfs/write.c, branch linux-3.1.y

nfs: don't try to migrate pages with active requests

2011-11-11T17:43:14+00:00

commit 2da956523526e440ef4f4dd174e26f5ac06fe011 upstream.

nfs_find_and_lock_request will take a reference to the nfs_page and
will then put it if the req is already locked. It's possible though
that the reference will be the last one. That put then can kick off
a whole series of reference puts:

nfs_page
   nfs_open_context
      dentry
          inode

If the inode ends up being deleted, then the VFS will call
truncate_inode_pages. That function will try to take the page lock, but
it was already locked when migrate_page was called. The code
deadlocks.

Fix this by simply refusing the migration request if PagePrivate is
already set, indicating that the page is already associated with an
active read or write request.

We've had a customer test a backported version of this patch and
the preliminary results seem good.

Cc: Andrea Arcangeli 
Reported-by: Harshula Jayasuriya 
Signed-off-by: Jeff Layton 
Signed-off-by: Trond Myklebust 
Signed-off-by: Greg Kroah-Hartman

nfs: don't redirty inode when ncommit == 0 in nfs_commit_unstable_pages

2011-11-11T17:43:03+00:00

commit 3236c3e1adc0c7ec83eaff1de2d06746b7c5bb28 upstream.

commit 420e3646 allowed the kernel to reduce the number of unnecessary
commit calls by skipping the commit when there are a large number of
outstanding pages.

However, the current test in nfs_commit_unstable_pages does not handle
the edge condition properly. When ncommit == 0, then that means that the
kernel doesn't need to do anything more for the inode. The current test
though in the WB_SYNC_NONE case will return true, and the inode will end
up being marked dirty. Once that happens the inode will never be clean
until there's a WB_SYNC_ALL flush.

Fix this by immediately returning from nfs_commit_unstable_pages when
ncommit == 0.

Mike noticed this problem initially in RHEL5 (2.6.18-based kernel) which
has a backported version of 420e3646. The inode cache there was growing
very large. The inode cache was unable to be shrunk since the inodes
were all marked dirty. Calling sync() would essentially "fix" the
problem -- the WB_SYNC_ALL flush would result in the inodes all being
marked clean.

What I'm not clear on is how big a problem this is in mainline kernels
as the writeback code there is very different. Either way, it seems
incorrect to re-mark the inode dirty in this case.

Reported-by: Mike McLean 
Signed-off-by: Jeff Layton 
Signed-off-by: Trond Myklebust 
Signed-off-by: Greg Kroah-Hartman

Revert "NFS: Ensure that writeback_single_inode() calls write_inode() when syncing"

2011-11-11T17:43:02+00:00

commit 59b7c05fffba030e5d9e72324691e2f99aa69b79 upstream.

This reverts commit b80c3cb628f0ebc241b02e38dd028969fb8026a2.

The reverted commit was rendered obsolete by a VFS fix: commit
5547e8aac6f71505d621a612de2fca0dd988b439 (writeback: Update dirty flags in
two steps). We now no longer need to worry about writeback_single_inode()
missing our marking the inode for COMMIT in 'do_writepages()' call.

Reverting this patch, fixes a performance regression in which the inode
would continuously get queued to the dirty list, causing the writeback
code to unnecessarily try to send a COMMIT.

Signed-off-by: Trond Myklebust 
Tested-by: Simon Kirby 
Signed-off-by: Greg Kroah-Hartman

pnfs: recoalesce when ld write pagelist fails

2011-11-11T17:42:58+00:00

commit 8ce160c5ef06cc89c2b6b26bfa5ef7a5ce2c93e0 upstream.

For pnfs pagelist write failure, we need to pg_recoalesce and resend IO to
mds.

Signed-off-by: Peng Tao 
Signed-off-by: Jim Rees 
Signed-off-by: Trond Myklebust 
Signed-off-by: Greg Kroah-Hartman

NFS: Fix a typo in nfs_flush_multi

2011-09-13T21:06:57+00:00

Fix a typo which causes an Oops in the RPC layer, when using wsize < 4k.

Signed-off-by: Trond Myklebust 
Tested-by: Sricharan R

Merge branch 'nfs-for-3.1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

2011-07-27T20:23:02+00:00

* 'nfs-for-3.1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (44 commits)
  NFSv4: Don't use the delegation->inode in nfs_mark_return_delegation()
  nfs: don't use d_move in nfs_async_rename_done
  RDMA: Increasing RPCRDMA_MAX_DATA_SEGS
  SUNRPC: Replace xprt->resend and xprt->sending with a priority queue
  SUNRPC: Allow caller of rpc_sleep_on() to select priority levels
  SUNRPC: Support dynamic slot allocation for TCP connections
  SUNRPC: Clean up the slot table allocation
  SUNRPC: Initalise the struct xprt upon allocation
  SUNRPC: Ensure that we grab the XPRT_LOCK before calling xprt_alloc_slot
  pnfs: simplify pnfs files module autoloading
  nfs: document nfsv4 sillyrename issues
  NFS: Convert nfs4_set_ds_client to EXPORT_SYMBOL_GPL
  SUNRPC: Convert the backchannel exports to EXPORT_SYMBOL_GPL
  SUNRPC: sunrpc should not explicitly depend on NFS config options
  NFS: Clean up - simplify the switch to read/write-through-MDS
  NFS: Move the pnfs write code into pnfs.c
  NFS: Move the pnfs read code into pnfs.c
  NFS: Allow the nfs_pageio_descriptor to signal that a re-coalesce is needed
  NFS: Use the nfs_pageio_descriptor->pg_bsize in the read/write request
  NFS: Cache rpc_ops in struct nfs_pageio_descriptor
  ...

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/writeback

2011-07-26T17:39:54+00:00

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/writeback: (27 commits)
  mm: properly reflect task dirty limits in dirty_exceeded logic
  writeback: don't busy retry writeback on new/freeing inodes
  writeback: scale IO chunk size up to half device bandwidth
  writeback: trace global_dirty_state
  writeback: introduce max-pause and pass-good dirty limits
  writeback: introduce smoothed global dirty limit
  writeback: consolidate variable names in balance_dirty_pages()
  writeback: show bdi write bandwidth in debugfs
  writeback: bdi write bandwidth estimation
  writeback: account per-bdi accumulated written pages
  writeback: make writeback_control.nr_to_write straight
  writeback: skip tmpfs early in balance_dirty_pages_ratelimited_nr()
  writeback: trace event writeback_queue_io
  writeback: trace event writeback_single_inode
  writeback: remove .nonblocking and .encountered_congestion
  writeback: remove writeback_control.more_io
  writeback: skip balance_dirty_pages() for in-memory fs
  writeback: add bdi_dirty_limit() kernel-doc
  writeback: avoid extra sync work at enqueue time
  writeback: elevate queue_io() into wb_writeback()
  ...

Fix up trivial conflicts in fs/fs-writeback.c and mm/filemap.c

Merge branch 'master' into devel and apply fixup from Stephen Rothwell:

2011-07-25T18:53:52+00:00

vfs/nfs: fixup for nfs_open_context change

Signed-off-by: Stephen Rothwell 
Signed-off-by: Trond Myklebust

nfs_open_context doesn't need struct path either

2011-07-20T05:43:44+00:00

just dentry, please...

Signed-off-by: Al Viro

NFS: Clean up - simplify the switch to read/write-through-MDS

2011-07-15T13:12:22+00:00

Use nfs_pageio_reset_read_mds and nfs_pageio_reset_write_mds instead of
completely reinitialising the struct nfs_pageio_descriptor.

Signed-off-by: Trond Myklebust