From: David Howells dhowells@redhat.com
[ Upstream commit 2aeb8c86d49967552394d5e723f87454cb53f501 ]
If a callback break occurs (change notification), afs_getattr() needs to issue an FS.FetchStatus RPC operation to update the status of the file being examined by the stat-family of system calls.
Fix afs_getattr() to do this if AFS_VNODE_CB_PROMISED has been cleared on a vnode by a callback break. Skip this if AT_STATX_DONT_SYNC is set.
This can be tested by appending to a file on one AFS client and then using "stat -L" to examine its length on a machine running kafs. This can also be watched through tracing on the kafs machine. The callback break is seen:
kworker/1:1-46 [001] ..... 978.910812: afs_cb_call: c=0000005f YFSCB.CallBack kworker/1:1-46 [001] ...1. 978.910829: afs_cb_break: 100058:23b4c:242d2c2 b=2 s=1 break-cb kworker/1:1-46 [001] ..... 978.911062: afs_call_done: c=0000005f ret=0 ab=0 [0000000082994ead]
And then the stat command generated no traffic if unpatched, but with this change a call to fetch the status can be observed:
stat-4471 [000] ..... 986.744122: afs_make_fs_call: c=000000ab 100058:023b4c:242d2c2 YFS.FetchStatus stat-4471 [000] ..... 986.745578: afs_call_done: c=000000ab ret=0 ab=0 [0000000087fc8c84]
Fixes: 08e0e7c82eea ("[AF_RXRPC]: Make the in-kernel AFS filesystem use AF_RXRPC.") Reported-by: Markus Suvanto markus.suvanto@gmail.com Signed-off-by: David Howells dhowells@redhat.com cc: Marc Dionne marc.dionne@auristor.com cc: linux-afs@lists.infradead.org Tested-by: Markus Suvanto markus.suvanto@gmail.com Tested-by: kafs-testing+fedora34_64checkkafs-build-496@auristor.com Link: https://bugzilla.kernel.org/show_bug.cgi?id=216010 Link: https://lore.kernel.org/r/165308359800.162686.14122417881564420962.stgit@war... # v1 Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/afs/inode.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/fs/afs/inode.c b/fs/afs/inode.c index 8fcffea2daf5..a47666ba48f5 100644 --- a/fs/afs/inode.c +++ b/fs/afs/inode.c @@ -728,10 +728,22 @@ int afs_getattr(struct user_namespace *mnt_userns, const struct path *path, { struct inode *inode = d_inode(path->dentry); struct afs_vnode *vnode = AFS_FS_I(inode); - int seq = 0; + struct key *key; + int ret, seq = 0;
_enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
+ if (!(query_flags & AT_STATX_DONT_SYNC) && + !test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) { + key = afs_request_key(vnode->volume->cell); + if (IS_ERR(key)) + return PTR_ERR(key); + ret = afs_validate(vnode, key); + key_put(key); + if (ret < 0) + return ret; + } + do { read_seqbegin_or_lock(&vnode->cb_lock, &seq); generic_fillattr(&init_user_ns, inode, stat);