NFS: Avoid writeback threads getting stuck in mempool_alloc()

[ Upstream commit 0bae835b63c53f86cdc524f5962e39409585b22c ]

In a low memory situation, allow the NFS writeback code to fail without
ge

NFS: Avoid writeback threads getting stuck in mempool_alloc()

[ Upstream commit 0bae835b63c53f86cdc524f5962e39409585b22c ]

In a low memory situation, allow the NFS writeback code to fail without
getting stuck in infinite loops in mempool_alloc().

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

NFS: nfsiod should not block forever in mempool_alloc()

[ Upstream commit 515dcdcd48736576c6f5c197814da6f81c60a21e ]

The concern is that since nfsiod is sometimes required to kick off a
commit, it

NFS: nfsiod should not block forever in mempool_alloc()

[ Upstream commit 515dcdcd48736576c6f5c197814da6f81c60a21e ]

The concern is that since nfsiod is sometimes required to kick off a
commit, it can get locked up waiting forever in mempool_alloc() instead
of failing gracefully and leaving the commit until later.

Try to allocate from the slab first, with GFP_KERNEL | __GFP_NORETRY,
then fall back to a non-blocking attempt to allocate from the memory
pool.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

NFS: Use of mapping_set_error() results in spurious errors

[ Upstream commit 6c984083ec2453dfd3fcf98f392f34500c73e3f2 ]

The use of mapping_set_error() in conjunction with calls to
filemap_check_err

NFS: Use of mapping_set_error() results in spurious errors

[ Upstream commit 6c984083ec2453dfd3fcf98f392f34500c73e3f2 ]

The use of mapping_set_error() in conjunction with calls to
filemap_check_errors() is problematic because every error gets reported
as either an EIO or an ENOSPC by filemap_check_errors() in functions
such as filemap_write_and_wait() or filemap_write_and_wait_range().
In almost all cases, we prefer to use the more nuanced wb errors.

Fixes: b8946d7bfb94 ("NFS: Revalidate the file mapping on all fatal writeback errors")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

NFS: Fix up commit deadlocks

[ Upstream commit 133a48abf6ecc535d7eddc6da1c3e4c972445882 ]

If O_DIRECT bumps the commit_info rpcs_out field, then that could lead
to fsync() hangs. The fix is to ensu

NFS: Fix up commit deadlocks

[ Upstream commit 133a48abf6ecc535d7eddc6da1c3e4c972445882 ]

If O_DIRECT bumps the commit_info rpcs_out field, then that could lead
to fsync() hangs. The fix is to ensure that O_DIRECT calls
nfs_commit_end().

Fixes: 723c921e7dfc ("sched/wait, fs/nfs: Convert wait_on_atomic_t() usage to the new wait_var_event() API")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

NFS: Fix deadlocks in nfs_scan_commit_list()

[ Upstream commit 64a93dbf25d3a1368bb58ddf0f61d0a92d7479e3 ]

Partially revert commit 2ce209c42c01 ("NFS: Wait for requests that are
locked on the commit

NFS: Fix deadlocks in nfs_scan_commit_list()

[ Upstream commit 64a93dbf25d3a1368bb58ddf0f61d0a92d7479e3 ]

Partially revert commit 2ce209c42c01 ("NFS: Wait for requests that are
locked on the commit list"), since it can lead to deadlocks between
commit requests and nfs_join_page_group().
For now we should assume that any locked requests on the commit list are
either about to be removed and committed by another task, or the writes
they describe are about to be retransmitted. In either case, we should
not need to worry.

Fixes: 2ce209c42c01 ("NFS: Wait for requests that are locked on the commit list")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

NFSv4.1 identify and mark RPC tasks that can move between transports

In preparation for when we can re-try a task on a different transport,
identify and mark such RPC tasks as moveable. Only 4.1+ op

NFSv4.1 identify and mark RPC tasks that can move between transports

In preparation for when we can re-try a task on a different transport,
identify and mark such RPC tasks as moveable. Only 4.1+ operarations can
be re-tried on a different transport.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

show more ...

NFSv4: Don't modify the change attribute cached in the inode

When the client is caching data and a write delegation is held, then the
server may send a CB_GETATTR to query the attributes. When this

NFSv4: Don't modify the change attribute cached in the inode

When the client is caching data and a write delegation is held, then the
server may send a CB_GETATTR to query the attributes. When this happens,
the client is supposed to bump the change attribute value that it
returns if it holds cached data.
However that process uses a value that is stored in the delegation. We
do not want to bump the change attribute held in the inode.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

show more ...

NFS: Separate tracking of file mode cache validity from the uid/gid

chown()/chgrp() and chmod() are separate operations, and in addition,
there are mode operations that are performed automatically b

NFS: Separate tracking of file mode cache validity from the uid/gid

chown()/chgrp() and chmod() are separate operations, and in addition,
there are mode operations that are performed automatically by the
server. So let's track mode validity separately from the file ownership
validity.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

show more ...

NFS: Replace use of NFS_INO_REVAL_PAGECACHE when checking cache validity

When checking cache validity, be more specific than just 'we want to
check the page cache validity'. In almost all cases, we

NFS: Replace use of NFS_INO_REVAL_PAGECACHE when checking cache validity

When checking cache validity, be more specific than just 'we want to
check the page cache validity'. In almost all cases, we want to check
that change attribute, and possibly also the size.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

show more ...

NFS: Fix open coded versions of nfs_set_cache_invalid()

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

Signed-off-by: Trond Mykle

NFS: Fix open coded versions of nfs_set_cache_invalid()

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

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

show more ...

NFS: Add support for eager writes

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 im

NFS: Add support for eager writes

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 <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

show more ...

NFS: Optimise sparse writes past the end of file

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 p

NFS: Optimise sparse writes past the end of file

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 <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

show more ...

mm/writeback: discard NR_UNSTABLE_NFS, use NR_WRITEBACK instead

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

mm/writeback: discard NR_UNSTABLE_NFS, use NR_WRITEBACK instead

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 <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Acked-by: Michal Hocko <mhocko@suse.com> [mm]
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Link: http://lkml.kernel.org/r/87d06j7gqa.fsf@notabene.neil.brown.name
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

NFS/pnfs: Don't use RPC_TASK_CRED_NOREF with pnfs

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

NFS/pnfs: Don't use RPC_TASK_CRED_NOREF with pnfs

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 <trond.myklebust@hammerspace.com>

show more ...

NFS: Try to join page groups before an O_DIRECT retransmission

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

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.co

NFS: Try to join page groups before an O_DIRECT retransmission

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

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

show more ...

NFS: Refactor nfs_lock_and_join_requests()

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

NFS: Refactor nfs_lock_and_join_requests()

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 <trond.myklebust@hammerspace.com>

show more ...

NFS: Clean up nfs_lock_and_join_requests()

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.

Sig

NFS: Clean up nfs_lock_and_join_requests()

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 <trond.myklebust@hammerspace.com>

show more ...

NFS: Fix races nfs_page_group_destroy() vs nfs_destroy_unlinked_subrequests()

When a subrequest is being detached from the subgroup, we want to
ensure that it is not holding the group lock, or in th

NFS: Fix races nfs_page_group_destroy() vs nfs_destroy_unlinked_subrequests()

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 <trond.myklebust@hammerspace.com>

show more ...

NFS: Fix a page leak in nfs_destroy_unlinked_subrequests()

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

Fixes: 5b2b5187fa85 ("NFS: Fix nfs_p

NFS: Fix a page leak in nfs_destroy_unlinked_subrequests()

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 <trond.myklebust@hammerspace.com>

show more ...

NFS: Fix O_DIRECT commit verifier handling

Instead of trying to save the commit verifiers and checking them against
previous writes, adopt the same strategy as for buffered writes, of
just checking

NFS: Fix O_DIRECT commit verifier handling

Instead of trying to save the commit verifiers and checking them against
previous writes, adopt the same strategy as for buffered writes, of
just checking the verifiers at commit time.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

show more ...

NFS/pNFS: Refactor pnfs_generic_commit_pagelist()

Refactor pnfs_generic_commit_pagelist() to simplify the conversion
to layout segment based commit lists.

Signed-off-by: Trond Myklebust <trond.mykl

NFS/pNFS: Refactor pnfs_generic_commit_pagelist()

Refactor pnfs_generic_commit_pagelist() to simplify the conversion
to layout segment based commit lists.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

show more ...

NFS: Assume cred is pinned by open context in I/O requests

In read/write/commit, we should be able to assume that the cred is
pinned by the open context.

Signed-off-by: Trond Myklebust <trond.mykle

NFS: Assume cred is pinned by open context in I/O requests

In read/write/commit, we should be able to assume that the cred is
pinned by the open context.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

show more ...

NFS: When resending after a short write, reset the reply count to zero

If we're resending a write due to a short read or write, ensure we
reset the reply count to zero.

Signed-off-by: Trond Myklebu

NFS: When resending after a short write, reset the reply count to zero

If we're resending a write due to a short read or write, ensure we
reset the reply count to zero.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

show more ...

NFS: Clean up generic file commit tracepoint

Clean up the generic file commit tracepoints to use a 64-bit value
for the verifier, and to display the pNFS filehandle, if it exists.

Signed-off-by: Tr

NFS: Clean up generic file commit tracepoint

Clean up the generic file commit tracepoints to use a 64-bit value
for the verifier, and to display the pNFS filehandle, if it exists.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

show more ...

NFS: Clean up generic writeback tracepoints

Clean up the generic writeback tracepoints so they do pass the
full structures as arguments. Also ensure we report the number
of bytes actually written.

NFS: Clean up generic writeback tracepoints

Clean up the generic writeback tracepoints so they do pass the
full structures as arguments. Also ensure we report the number
of bytes actually written.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

show more ...