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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The cell name stored in the afs_cell struct is a 64-char + NUL buffer -
when it needs to be able to handle up to AFS_MAXCELLNAME (256 chars) + NUL.
Fix this by changing the array to a pointer and allocating the string.
Found using Coverity.
Fixes: 989782dcdc91 ("afs: Overhaul cell database management")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The fileserver probe timer, net->fs_probe_timer, isn't cancelled when
the kafs module is being removed and so the count it holds on
net->servers_outstanding doesn't get dropped..
This causes rmmod to wait forever. The hung process shows a stack like:
afs_purge_servers+0x1b5/0x23c [kafs]
afs_net_exit+0x44/0x6e [kafs]
ops_exit_list+0x72/0x93
unregister_pernet_operations+0x14c/0x1ba
unregister_pernet_subsys+0x1d/0x2a
afs_exit+0x29/0x6f [kafs]
__do_sys_delete_module.isra.0+0x1a2/0x24b
do_syscall_64+0x51/0x95
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fix this by:
(1) Attempting to cancel the probe timer and, if successful, drop the
count that the timer was holding.
(2) Make the timer function just drop the count and not schedule the
prober if the afs portion of net namespace is being destroyed.
Also, whilst we're at it, make the following changes:
(3) Initialise net->servers_outstanding to 1 and decrement it before
waiting on it so that it doesn't generate wake up events by being
decremented to 0 until we're cleaning up.
(4) Switch the atomic_dec() on ->servers_outstanding for ->fs_timer in
afs_purge_servers() to use the helper function for that.
Fixes: f6cbb368bcb0 ("afs: Actively poll fileservers to maintain NAT or firewall openings")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix afs_do_lookup()'s fallback case for when FS.InlineBulkStatus isn't
supported by the server.
In the fallback, it calls FS.FetchStatus for the specific vnode it's
meant to be looking up. Commit b6489a49f7b7 broke this by renaming one
of the two identically-named afs_fetch_status_operation descriptors to
something else so that one of them could be made non-static. The site
that used the renamed one, however, wasn't renamed and didn't produce
any warning because the other was declared in a header.
Fix this by making afs_do_lookup() use the renamed variant.
Note that there are two variants of the success method because one is
called from ->lookup() where we may or may not have an inode, but can't
call iget until after we've talked to the server - whereas the other is
called from within iget where we have an inode, but it may or may not be
initialised.
The latter variant expects there to be an inode, but because it's being
called from there former case, there might not be - resulting in an oops
like the following:
BUG: kernel NULL pointer dereference, address: 00000000000000b0
...
RIP: 0010:afs_fetch_status_success+0x27/0x7e
...
Call Trace:
afs_wait_for_operation+0xda/0x234
afs_do_lookup+0x2fe/0x3c1
afs_lookup+0x3c5/0x4bd
__lookup_slow+0xcd/0x10f
walk_component+0xa2/0x10c
path_lookupat.isra.0+0x80/0x110
filename_lookup+0x81/0x104
vfs_statx+0x76/0x109
__do_sys_newlstat+0x39/0x6b
do_syscall_64+0x4c/0x78
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: b6489a49f7b7 ("afs: Fix silly rename")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix AFS's silly rename by the following means:
(1) Set the destination directory in afs_do_silly_rename() so as to avoid
misbehaviour and indicate that the directory data version will
increment by 1 so as to avoid warnings about unexpected changes in the
DV. Also indicate that the ctime should be updated to avoid xfstest
grumbling.
(2) Note when the server indicates that a directory changed more than we
expected (AFS_OPERATION_DIR_CONFLICT), indicating a conflict with a
third party change, checking on successful completion of unlink and
rename.
The problem is that the FS.RemoveFile RPC op doesn't report the status
of the unlinked file, though YFS.RemoveFile2 does. This can be
mitigated by the assumption that if the directory DV cranked by
exactly 1, we can be sure we removed one link from the file; further,
ordinarily in AFS, files cannot be hardlinked across directories, so
if we reduce nlink to 0, the file is deleted.
However, if the directory DV jumps by more than 1, we cannot know if a
third party intervened by adding or removing a link on the file we
just removed a link from.
The same also goes for any vnode that is at the destination of the
FS.Rename RPC op.
(3) Make afs_vnode_commit_status() apply the nlink drop inside the cb_lock
section along with the other attribute updates if ->op_unlinked is set
on the descriptor for the appropriate vnode.
(4) Issue a follow up status fetch to the unlinked file in the event of a
third party conflict that makes it impossible for us to know if we
actually deleted the file or not.
(5) Provide a flag, AFS_VNODE_SILLY_DELETED, to make afs_getattr() lie to
the user about the nlink of a silly deleted file so that it appears as
0, not 1.
Found with the generic/035 and generic/084 xfstests.
Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
afs_vnode_commit_status() is only ever called if op->error is 0, so remove
the op->error checks from the function.
Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Signed-off-by: David Howells <dhowells@redhat.com>
afs_check_for_remote_deletion() checks to see if error ENOENT is returned
by the server in response to an operation and, if so, marks the primary
vnode as having been deleted as the FID is no longer valid.
However, it's being called from the operation success functions, where no
abort has happened - and if an inline abort is recorded, it's handled by
afs_vnode_commit_status().
Fix this by actually calling the operation aborted method if provided and
having that point to afs_check_for_remote_deletion().
Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Signed-off-by: David Howells <dhowells@redhat.com>
Remove afs_operation::abort_code as it's read but never set. Use ac.abort_code instead. Signed-off-by: David Howells <dhowells@redhat.com>
Fix yfs_fs_fetch_status() to honour the vnode selector in
op->fetch_status.which as does afs_fs_fetch_status() that allows
afs_do_lookup() to use this as an alternative to the InlineBulkStatus RPC
call if not implemented by the server.
This doesn't matter in the current code as YFS servers always implement
InlineBulkStatus, but a subsequent will call it on YFS servers too in some
circumstances.
Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Signed-off-by: David Howells <dhowells@redhat.com>
Remove yfs_fs_fetch_file_status() as it's no longer used. Signed-off-by: David Howells <dhowells@redhat.com>