linux-stable.git/fs/ceph, branch v5.8.4

ceph: fix use-after-free for fsc->mdsc

2020-08-26T09:49:06+00:00

[ Upstream commit a7caa88f8b72c136f9a401f498471b8a8e35370d ]

If the ceph_mdsc_init() fails, it will free the mdsc already.

Reported-by: syzbot+b57f46d8d6ea51960b8c@syzkaller.appspotmail.com
Signed-off-by: Xiubo Li 
Reviewed-by: Jeff Layton 
Signed-off-by: Ilya Dryomov 
Signed-off-by: Sasha Levin

ceph: handle zero-length feature mask in session messages

2020-08-21T11:15:00+00:00

commit 02e37571f9e79022498fd0525c073b07e9d9ac69 upstream.

Most session messages contain a feature mask, but the MDS will
routinely send a REJECT message with one that is zero-length.

Commit 0fa8263367db ("ceph: fix endianness bug when handling MDS
session feature bits") fixed the decoding of the feature mask,
but failed to account for the MDS sending a zero-length feature
mask. This causes REJECT message decoding to fail.

Skip trying to decode a feature mask if the word count is zero.

Cc: stable@vger.kernel.org
URL: https://tracker.ceph.com/issues/46823
Fixes: 0fa8263367db ("ceph: fix endianness bug when handling MDS session feature bits")
Signed-off-by: Jeff Layton 
Reviewed-by: Ilya Dryomov 
Tested-by: Patrick Donnelly 
Signed-off-by: Ilya Dryomov 
Signed-off-by: Greg Kroah-Hartman

ceph: set sec_context xattr on symlink creation

2020-08-21T11:15:00+00:00

commit b748fc7a8763a5b3f8149f12c45711cd73ef8176 upstream.

Symlink inodes should have the security context set in their xattrs on
creation. We already set the context on creation, but we don't attach
the pagelist. The effect is that symlink inodes don't get an SELinux
context set on them at creation, so they end up unlabeled instead of
inheriting the proper context. Make it do so.

Cc: stable@vger.kernel.org
Signed-off-by: Jeff Layton 
Reviewed-by: Ilya Dryomov 
Signed-off-by: Ilya Dryomov 
Signed-off-by: Greg Kroah-Hartman

ceph: skip checking caps when session reconnecting and releasing reqs

2020-06-01T11:22:53+00:00

It make no sense to check the caps when reconnecting to mds. And
for the async dirop caps, they will be put by its _cb() function,
so when releasing the requests, it will make no sense too.

URL: https://tracker.ceph.com/issues/45635
Signed-off-by: Xiubo Li 
Reviewed-by: "Yan, Zheng" 
Signed-off-by: Ilya Dryomov

ceph: make sure mdsc->mutex is nested in s->s_mutex to fix dead lock

2020-06-01T11:22:53+00:00

send_mds_reconnect takes the s_mutex while the mdsc->mutex is already
held. That inverts the locking order documented in mds_client.h. Drop
the mdsc->mutex, acquire the s_mutex and then reacquire the mdsc->mutex
to prevent a deadlock.

URL: https://tracker.ceph.com/issues/45609
Signed-off-by: Xiubo Li 
Reviewed-by: Jeff Layton 
Signed-off-by: Ilya Dryomov

ceph: don't return -ESTALE if there's still an open file

2020-06-01T11:22:53+00:00

Similarly to commit 03f219041fdb ("ceph: check i_nlink while converting
a file handle to dentry"), this fixes another corner case with
name_to_handle_at/open_by_handle_at.  The issue has been detected by
xfstest generic/467, when doing:

 - name_to_handle_at("/cephfs/myfile")
 - open("/cephfs/myfile")
 - unlink("/cephfs/myfile")
 - sync; sync;
 - drop caches
 - open_by_handle_at()

The call to open_by_handle_at should not fail because the file hasn't been
deleted yet (only unlinked) and we do have a valid handle to it.  -ESTALE
shall be returned only if i_nlink is 0 *and* i_count is 1.

This patch also makes sure we have LINK caps before checking i_nlink.

Signed-off-by: Luis Henriques 
Reviewed-by: Jeff Layton 
Acked-by: Amir Goldstein 
Signed-off-by: Ilya Dryomov

ceph: allow rename operation under different quota realms

2020-06-01T11:22:53+00:00

Returning -EXDEV when trying to 'mv' files/directories from different
quota realms results in copy+unlink operations instead of the faster
CEPH_MDS_OP_RENAME.  This will occur even when there aren't any quotas
set in the destination directory, or if there's enough space left for
the new file(s).

This patch adds a new helper function to be called on rename operations
which will allow these operations if they can be executed.  This patch
mimics userland fuse client commit b8954e5734b3 ("client:
optimize rename operation under different quota root").

Since ceph_quota_is_same_realm() is now called only from this new
helper, make it static.

URL: https://tracker.ceph.com/issues/44791
Signed-off-by: Luis Henriques 
Reviewed-by: Jeff Layton 
Signed-off-by: Ilya Dryomov

ceph: normalize 'delta' parameter usage in check_quota_exceeded

2020-06-01T11:22:53+00:00

Function check_quota_exceeded() uses delta parameter only for the
QUOTA_CHECK_MAX_BYTES_OP operation.  Using this parameter also for
MAX_FILES will makes the code cleaner and will be required to support
cross-quota-tree renames.

Signed-off-by: Luis Henriques 
Reviewed-by: Jeff Layton 
Signed-off-by: Ilya Dryomov

ceph: ceph_kick_flushing_caps needs the s_mutex

2020-06-01T11:22:53+00:00

The mdsc->cap_dirty_lock is not held while walking the list in
ceph_kick_flushing_caps, which is not safe.

ceph_early_kick_flushing_caps does something similar, but the
s_mutex is held while it's called and I think that guards against
changes to the list.

Ensure we hold the s_mutex when calling ceph_kick_flushing_caps,
and add some clarifying comments.

Signed-off-by: Jeff Layton 
Reviewed-by: "Yan, Zheng" 
Signed-off-by: Ilya Dryomov

ceph: request expedited service on session's last cap flush

2020-06-01T11:22:52+00:00

When flushing a lot of caps to the MDS's at once (e.g. for syncfs),
we can end up waiting a substantial amount of time for MDS replies, due
to the fact that it may delay some of them so that it can batch them up
together in a single journal transaction. This can lead to stalls when
calling sync or syncfs.

What we'd really like to do is request expedited service on the _last_
cap we're flushing back to the server. If the CHECK_CAPS_FLUSH flag is
set on the request and the current inode was the last one on the
session->s_cap_dirty list, then mark the request with
CEPH_CLIENT_CAPS_SYNC.

Note that this heuristic is not perfect. New inodes can race onto the
list after we've started flushing, but it does seem to fix some common
use cases.

URL: https://tracker.ceph.com/issues/44744
Reported-by: Jan Fajerski 
Signed-off-by: Jeff Layton 
Reviewed-by: "Yan, Zheng" 
Signed-off-by: Ilya Dryomov