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From: David Howells <dhowells@redhat.com>
To: Trond Myklebust <trondmy@hammerspace.com>,
	Anna Schumaker <anna.schumaker@netapp.com>,
	Steve French <sfrench@samba.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Matthew Wilcox <willy@infradead.org>
Cc: Jeff Layton <jlayton@redhat.com>,
	Dave Wysochanski <dwysocha@redhat.com>,
	dhowells@redhat.com, linux-cachefs@redhat.com,
	linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org,
	linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org,
	v9fs-developer@lists.sourceforge.net,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 01/13] afs: Fix interruption of operations
Date: Mon, 13 Jul 2020 17:37:07 +0100	[thread overview]
Message-ID: <159465822787.1377938.10874079234418111929.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <159465821598.1377938.2046362270225008168.stgit@warthog.procyon.org.uk>

The afs filesystem driver allows unstarted operations to be cancelled by
signal, but most of these can easily be restarted (mkdir for example).  The
primary culprits for reproducing this are those applications that use
SIGALRM to display a progress counter.

File lock-extension operation is marked uninterruptible as we have a
limited time in which to do it, and the release op is marked
uninterruptible also as if we fail to unlock a file, we'll have to wait 20
mins before anyone can lock it again.

The store operation logs a warning if it gets interruption, e.g.:

	kAFS: Unexpected error from FS.StoreData -4

because it's run from the background - but it can also be run from
fdatasync()-type things.  However, store options aren't marked
interruptible at the moment.

Fix this in the following ways:

 (1) Mark store operations as uninterruptible.  It might make sense to
     relax this for certain situations, but I'm not sure how to make sure
     that background store ops aren't affected by signals to foreground
     processes that happen to trigger them.

 (2) In afs_get_io_locks(), where we're getting the serialisation lock for
     talking to the fileserver, return ERESTARTSYS rather than EINTR
     because a lot of the operations (e.g. mkdir) are restartable if we
     haven't yet started sending the op to the server.

Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Signed-off-by: David Howells <dhowells@redhat.com>
---

 fs/afs/fs_operation.c |    4 ++--
 fs/afs/write.c        |    1 +
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/afs/fs_operation.c b/fs/afs/fs_operation.c
index c264839b2fd0..24fd163c6323 100644
--- a/fs/afs/fs_operation.c
+++ b/fs/afs/fs_operation.c
@@ -71,7 +71,7 @@ static bool afs_get_io_locks(struct afs_operation *op)
 		swap(vnode, vnode2);
 
 	if (mutex_lock_interruptible(&vnode->io_lock) < 0) {
-		op->error = -EINTR;
+		op->error = -ERESTARTSYS;
 		op->flags |= AFS_OPERATION_STOP;
 		_leave(" = f [I 0]");
 		return false;
@@ -80,7 +80,7 @@ static bool afs_get_io_locks(struct afs_operation *op)
 
 	if (vnode2) {
 		if (mutex_lock_interruptible_nested(&vnode2->io_lock, 1) < 0) {
-			op->error = -EINTR;
+			op->error = -ERESTARTSYS;
 			op->flags |= AFS_OPERATION_STOP;
 			mutex_unlock(&vnode->io_lock);
 			op->flags &= ~AFS_OPERATION_LOCK_0;
diff --git a/fs/afs/write.c b/fs/afs/write.c
index abfc8d3dc20c..60918b80b729 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -449,6 +449,7 @@ static int afs_store_data(struct address_space *mapping,
 	op->store.first_offset = offset;
 	op->store.last_to = to;
 	op->mtime = vnode->vfs_inode.i_mtime;
+	op->flags |= AFS_OPERATION_UNINTR;
 	op->ops = &afs_store_data_operation;
 
 try_next_key:



  reply	other threads:[~2020-07-13 16:37 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-13 16:36 [PATCH 00/13] fscache: Rewrite 3: Make AFS use it David Howells
2020-07-13 16:37 ` David Howells [this message]
2020-07-13 16:37 ` [PATCH 02/13] afs: Move key to afs_read struct David Howells
2020-07-13 16:37   ` David Howells
2020-07-13 16:37 ` [PATCH 03/13] afs: Don't truncate iter during data fetch David Howells
2020-07-13 16:37   ` David Howells
2020-07-13 16:37 ` [PATCH 04/13] afs: Log remote unmarshalling errors David Howells
2020-07-13 16:37   ` David Howells
2020-07-13 16:37 ` [PATCH 05/13] afs: Set up the iov_iter before calling afs_extract_data() David Howells
2020-07-13 16:37   ` David Howells
2020-07-13 16:38 ` [PATCH 06/13] afs: Use ITER_MAPPING for writing David Howells
2020-07-13 16:38   ` David Howells
2020-07-13 16:38 ` [PATCH 07/13] afs: Interpose struct fscache_io_request into struct afs_read David Howells
2020-07-13 16:38   ` David Howells
2020-07-13 16:38 ` [PATCH 08/13] afs: Note the amount transferred in fetch-data delivery David Howells
2020-07-13 16:38   ` David Howells
2020-07-13 16:38 ` [PATCH 09/13] afs: Wait on PG_fscache before modifying/releasing a page David Howells
2020-07-13 16:38 ` [PATCH 10/13] afs: Use new fscache I/O API David Howells
2020-07-13 16:38   ` David Howells
2020-07-13 16:39 ` [PATCH 11/13] afs: Copy local writes to the cache when writing to the server David Howells
2020-07-13 16:39 ` [PATCH 12/13] afs: Invoke fscache_resize_cookie() when handling ATTR_SIZE for setattr David Howells
2020-07-13 16:39 ` [PATCH 13/13] afs: Add O_DIRECT read support David Howells
2020-07-13 16:39   ` David Howells

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