| Message ID | 165308359800.162686.14122417881564420962.stgit@warthog.procyon.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | afs: Fix afs_getattr() to refetch file status if callback break occurred | expand |
pe, 2022-05-20 kello 22:53 +0100, David Howells kirjoitti: > 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 > Link: https://bugzilla.kernel.org/show_bug.cgi?id=216010 > --- > > 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 2fe402483ad5..30b066299d39 100644 > --- a/fs/afs/inode.c > +++ b/fs/afs/inode.c > @@ -740,10 +740,22 @@ 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); > > Tested-by: Markus Suvanto <markus.suvanto@gmail.com> -Markus
diff --git a/fs/afs/inode.c b/fs/afs/inode.c index 2fe402483ad5..30b066299d39 100644 --- a/fs/afs/inode.c +++ b/fs/afs/inode.c @@ -740,10 +740,22 @@ 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);
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 Link: https://bugzilla.kernel.org/show_bug.cgi?id=216010 --- fs/afs/inode.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)