kernel.git/fs/nfs/write.c, branch linux-5.16.y

NFS: Avoid writeback threads getting stuck in mempool_alloc()

2022-04-13T18:03:11Z

[ 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 Signed-off-by: Sasha Levin

NFS: nfsiod should not block forever in mempool_alloc()

2022-04-13T18:03:11Z

[ 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 Signed-off-by: Sasha Levin

SUNRPC: improve 'swap' handling: scheduling and PF_MEMALLOC

2022-04-08T12:06:28Z

[ Upstream commit 8db55a032ac7ac1ed7b98d6b1dc980e6378c652f ] rpc tasks can be marked as RPC_TASK_SWAPPER. This causes GFP_MEMALLOC to be used for some allocations. This is needed in some cases, but not in all where it is currently provided, and in some where it isn't provided. Currently *all* tasks associated with a rpc_client on which swap is enabled get the flag and hence some GFP_MEMALLOC support. GFP_MEMALLOC is provided for ->buf_alloc() but only swap-writes need it. However xdr_alloc_bvec does not get GFP_MEMALLOC - though it often does need it. xdr_alloc_bvec is called while the XPRT_LOCK is held. If this blocks, then it blocks all other queued tasks. So this allocation needs GFP_MEMALLOC for *all* requests, not just writes, when the xprt is used for any swap writes. Similarly, if the transport is not connected, that will block all requests including swap writes, so memory allocations should get GFP_MEMALLOC if swap writes are possible. So with this patch: 1/ we ONLY set RPC_TASK_SWAPPER for swap writes. 2/ __rpc_execute() sets PF_MEMALLOC while handling any task with RPC_TASK_SWAPPER set, or when handling any task that holds the XPRT_LOCKED lock on an xprt used for swap. This removes the need for the RPC_IS_SWAPPER() test in ->buf_alloc handlers. 3/ xprt_prepare_transmit() sets PF_MEMALLOC after locking any task to a swapper xprt. __rpc_execute() will clear it. 3/ PF_MEMALLOC is set for all the connect workers. Reviewed-by: Chuck Lever (for xprtrdma parts) Signed-off-by: NeilBrown Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin

NFS: Use of mapping_set_error() results in spurious errors

2022-04-08T12:06:23Z

[ 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 Signed-off-by: Sasha Levin

NFS: Remove redundant call to __set_page_dirty_nobuffers

2021-10-21T21:11:41Z

Remove a redundant call in nfs_updatepage(). nfs_writepage_setup() will have already called nfs_mark_request_dirty() on success. Signed-off-by: Trond Myklebust

SUNRPC: Trace calls to .rpc_call_done

2021-10-20T22:09:54Z

Introduce a single tracepoint that can replace simple dprintk call sites in upper layer "rpc_call_done" callbacks. Example: kworker/u24:2-1254 [001] 771.026677: rpc_stats_latency: task:00000001@00000002 xid=0x16a6f3c0 rpcbindv2 GETPORT backlog=446 rtt=101 execute=555 kworker/u24:2-1254 [001] 771.026677: rpc_task_call_done: task:00000001@00000002 flags=ASYNC|DYNAMIC|SOFT|SOFTCONN|SENT runstate=RUNNING|ACTIVE status=0 action=rpcb_getport_done kworker/u24:2-1254 [001] 771.026678: rpcb_setport: task:00000001@00000002 status=0 port=20048 Signed-off-by: Chuck Lever Signed-off-by: Trond Myklebust

NFS: Fix up commit deadlocks

2021-10-20T22:09:45Z

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

NFS: Fix deadlocks in nfs_scan_commit_list()

2021-10-10T09:05:54Z

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

NFS: Instrument i_size_write()

2021-10-10T09:05:54Z

Generate a trace event whenever the NFS client modifies the size of a file. These new events aid troubleshooting workloads that trigger races around size updates. There are four new trace points, all named nfs_size_something so they are easy to grep for or enable as a group with a single glob. Size updated on the server: kworker/u24:10-194 [010] 369.939174: nfs_size_update: fileid=00:28:2 fhandle=0x36fbbe51 version=1752899344277980615 cursize=250471 newsize=172083 Server-side size update reported via NFSv3 WCC attributes: fsx-1387 [006] 380.760686: nfs_size_wcc: fileid=00:28:2 fhandle=0x36fbbe51 version=1752899355909932456 cursize=146792 newsize=171216 File has been truncated locally: fsx-1387 [007] 369.437421: nfs_size_truncate: fileid=00:28:2 fhandle=0x36fbbe51 version=1752899231200117272 cursize=215244 newsize=0 File has been extended locally: fsx-1387 [007] 369.439213: nfs_size_grow: fileid=00:28:2 fhandle=0x36fbbe51 version=1752899343704248410 cursize=258048 newsize=262144 Signed-off-by: Chuck Lever Signed-off-by: Trond Myklebust

NFS: Fix up nfs_ctx_key_to_expire()

2021-10-04T00:49:05Z

If the cached credential exists but doesn't have any expiration callback then exit early. Fix up atomicity issues when replacing the credential with a new one since the existing code could lead to refcount leaks. Signed-off-by: Trond Myklebust