linux.git/fs/nfs/write.c, branch v5.12

NFS: Fix open coded versions of nfs_set_cache_invalid()

2021-03-08T21:13:55+00:00

nfs_set_cache_invalid() has code to handle delegations, and other
optimisations, so let's use it when appropriate.

Signed-off-by: Trond Myklebust 
Signed-off-by: Anna Schumaker

NFS: Add support for eager writes

2021-02-16T21:11:14+00:00

Support eager writing to the server, meaning that we write the data to
cache on the server, and wait for that to complete. This ensures that we
see ENOSPC errors immediately.

Signed-off-by: Trond Myklebust 
Signed-off-by: Anna Schumaker

NFS: Optimise sparse writes past the end of file

2021-02-08T16:26:14+00:00

If we're doing a write, and the entire page lies beyond the end-of-file,
then we can assume the write can be extended to cover the beginning of
the page, since we know the data in that region will be all zeros.

Signed-off-by: Trond Myklebust 
Signed-off-by: Anna Schumaker

mm/writeback: discard NR_UNSTABLE_NFS, use NR_WRITEBACK instead

2020-06-02T17:59:08+00:00

After an NFS page has been written it is considered "unstable" until a
COMMIT request succeeds.  If the COMMIT fails, the page will be
re-written.

These "unstable" pages are currently accounted as "reclaimable", either
in WB_RECLAIMABLE, or in NR_UNSTABLE_NFS which is included in a
'reclaimable' count.  This might have made sense when sending the COMMIT
required a separate action by the VFS/MM (e.g.  releasepage() used to
send a COMMIT).  However now that all writes generated by ->writepages()
will automatically be followed by a COMMIT (since commit 919e3bd9a875
("NFS: Ensure we commit after writeback is complete")) it makes more
sense to treat them as writeback pages.

So this patch removes NR_UNSTABLE_NFS and accounts unstable pages in
NR_WRITEBACK and WB_WRITEBACK.

A particular effect of this change is that when
wb_check_background_flush() calls wb_over_bg_threshold(), the latter
will report 'true' a lot less often as the 'unstable' pages are no
longer considered 'dirty' (as there is nothing that writeback can do
about them anyway).

Currently wb_check_background_flush() will trigger writeback to NFS even
when there are relatively few dirty pages (if there are lots of unstable
pages), this can result in small writes going to the server (10s of
Kilobytes rather than a Megabyte) which hurts throughput.  With this
patch, there are fewer writes which are each larger on average.

Where the NR_UNSTABLE_NFS count was included in statistics
virtual-files, the entry is retained, but the value is hard-coded as
zero.  static trace points and warning printks which mentioned this
counter no longer report it.

[akpm@linux-foundation.org: re-layout comment]
[akpm@linux-foundation.org: fix printk warning]
Signed-off-by: NeilBrown 
Signed-off-by: Andrew Morton 
Reviewed-by: Jan Kara 
Reviewed-by: Christoph Hellwig 
Acked-by: Trond Myklebust 
Acked-by: Michal Hocko 	[mm]
Cc: Christoph Hellwig 
Cc: Chuck Lever 
Link: http://lkml.kernel.org/r/87d06j7gqa.fsf@notabene.neil.brown.name
Signed-off-by: Linus Torvalds

NFS/pnfs: Don't use RPC_TASK_CRED_NOREF with pnfs

2020-05-13T13:55:36+00:00

When we're doing pnfs then the credential being used for the RPC call
is not necessarily the same as the one used in the open context, so
don't use RPC_TASK_CRED_NOREF.

Fixes: 612965072020 ("NFSv4: Avoid referencing the cred unnecessarily during NFSv4 I/O")
Signed-off-by: Trond Myklebust

NFS: Try to join page groups before an O_DIRECT retransmission

2020-04-01T17:37:57+00:00

If we have to retransmit requests, try to join their page groups
first.

Signed-off-by: Trond Myklebust

NFS: Refactor nfs_lock_and_join_requests()

2020-04-01T17:37:56+00:00

Refactor nfs_lock_and_join_requests() in order to separate out the
subrequest merging into its own function nfs_lock_and_join_group()
that can be used by O_DIRECT.

Signed-off-by: Trond Myklebust

NFS: Clean up nfs_lock_and_join_requests()

2020-04-01T17:37:56+00:00

Clean up nfs_lock_and_join_requests() to simplify the calculation
of the range covered by the page group, taking into account the
presence of mirrors.

Signed-off-by: Trond Myklebust

NFS: Fix races nfs_page_group_destroy() vs nfs_destroy_unlinked_subrequests()

2020-04-01T17:34:28+00:00

When a subrequest is being detached from the subgroup, we want to
ensure that it is not holding the group lock, or in the process
of waiting for the group lock.

Fixes: 5b2b5187fa85 ("NFS: Fix nfs_page_group_destroy() and nfs_lock_and_join_requests() race cases")
Signed-off-by: Trond Myklebust

NFS: Fix a page leak in nfs_destroy_unlinked_subrequests()

2020-04-01T14:11:22+00:00

When we detach a subrequest from the list, we must also release the
reference it holds to the parent.

Fixes: 5b2b5187fa85 ("NFS: Fix nfs_page_group_destroy() and nfs_lock_and_join_requests() race cases")
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: Trond Myklebust