linux.git/fs/ceph/locks.c, branch v3.19

ceph: fix file lock interruption

2014-12-17T17:09:49+00:00

When a lock operation is interrupted, current code sends a unlock request to
MDS to undo the lock operation. This method does not work as expected because
the unlock request can drop locks that have already been acquired.

The fix is use the newly introduced CEPH_LOCK_FCNTL_INTR/CEPH_LOCK_FLOCK_INTR
requests to interrupt blocked file lock request. These requests do not drop
locks that have alread been acquired, they only interrupt blocked file lock
request.

Signed-off-by: Yan, Zheng

locks: ensure that fl_owner is always initialized properly in flock and lease codepaths

2014-06-02T12:09:29+00:00

Currently, the fl_owner isn't set for flock locks. Some filesystems use
byte-range locks to simulate flock locks and there is a common idiom in
those that does:

    fl->fl_owner = (fl_owner_t)filp;
    fl->fl_start = 0;
    fl->fl_end = OFFSET_MAX;

Since flock locks are generally "owned" by the open file description,
move this into the common flock lock setup code. The fl_start and fl_end
fields are already set appropriately, so remove the unneeded setting of
that in flock ops in those filesystems as well.

Finally, the lease code also sets the fl_owner as if they were owned by
the process and not the open file description. This is incorrect as
leases have the same ownership semantics as flock locks. Set them the
same way. The lease code doesn't actually use the fl_owner value for
anything, so this is more for consistency's sake than a bugfix.

Reported-by: Trond Myklebust 
Signed-off-by: Jeff Layton 
Acked-by: Greg Kroah-Hartman  (Staging portion)
Acked-by: J. Bruce Fields

ceph: reserve caps for file layout/lock MDS requests

2014-04-28T19:55:41+00:00

Signed-off-by: Yan, Zheng 
Reviewed-by: Sage Weil

ceph: use fl->fl_file as owner identifier of flock and posix lock

2014-04-05T04:07:11+00:00

flock and posix lock should use fl->fl_file instead of process ID
as owner identifier. (posix lock uses fl->fl_owner. fl->fl_owner
is usually equal to fl->fl_file, but it also can be a customized
value). The process ID of who holds the lock is just for F_GETLK
fcntl(2).

The fix is rename the 'pid' fields of struct ceph_mds_request_args
and struct ceph_filelock to 'owner', rename 'pid_namespace' fields
to 'pid'. Assign fl->fl_file to the 'owner' field of lock messages.
We also set the most significant bit of the 'owner' field. MDS can
use that bit to distinguish between old and new clients.

The MDS counterpart of this patch modifies the flock code to not
take the 'pid_namespace' into consideration when checking conflict
locks.

Signed-off-by: Yan, Zheng 
Reviewed-by: Sage Weil

ceph: forbid mandatory file lock

2014-04-05T04:07:09+00:00

Signed-off-by: Yan, Zheng

ceph: use fl->fl_type to decide flock operation

2014-04-05T04:07:08+00:00

VFS does not directly pass flock's operation code to filesystem's
flock callback. It translates the operation code to the form how
posix lock's parameters are presented.

Signed-off-by: Yan, Zheng

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client

2013-07-09T19:39:10+00:00

Pull Ceph updates from Sage Weil:
 "There is some follow-on RBD cleanup after the last window's code drop,
  a series from Yan fixing multi-mds behavior in cephfs, and then a
  sprinkling of bug fixes all around.  Some warnings, sleeping while
  atomic, a null dereference, and cleanups"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (36 commits)
  libceph: fix invalid unsigned->signed conversion for timespec encoding
  libceph: call r_unsafe_callback when unsafe reply is received
  ceph: fix race between cap issue and revoke
  ceph: fix cap revoke race
  ceph: fix pending vmtruncate race
  ceph: avoid accessing invalid memory
  libceph: Fix NULL pointer dereference in auth client code
  ceph: Reconstruct the func ceph_reserve_caps.
  ceph: Free mdsc if alloc mdsc->mdsmap failed.
  ceph: remove sb_start/end_write in ceph_aio_write.
  ceph: avoid meaningless calling ceph_caps_revoking if sync_mode == WB_SYNC_ALL.
  ceph: fix sleeping function called from invalid context.
  ceph: move inode to proper flushing list when auth MDS changes
  rbd: fix a couple warnings
  ceph: clear migrate seq when MDS restarts
  ceph: check migrate seq before changing auth cap
  ceph: fix race between page writeback and truncate
  ceph: reset iov_len when discarding cap release messages
  ceph: fix cap release race
  libceph: fix truncate size calculation
  ...

ceph: fix up comment for ceph_count_locks() as to which lock to hold

2013-07-01T16:52:01+00:00

Signed-off-by: Jim Schutt 
Reviewed-by: Alex Elder

locks: protect most of the file_lock handling with i_lock

2013-06-29T08:57:42+00:00

Having a global lock that protects all of this code is a clear
scalability problem. Instead of doing that, move most of the code to be
protected by the i_lock instead. The exceptions are the global lists
that the ->fl_link sits on, and the ->fl_block list.

->fl_link is what connects these structures to the
global lists, so we must ensure that we hold those locks when iterating
over or updating these lists.

Furthermore, sound deadlock detection requires that we hold the
blocked_list state steady while checking for loops. We also must ensure
that the search and update to the list are atomic.

For the checking and insertion side of the blocked_list, push the
acquisition of the global lock into __posix_lock_file and ensure that
checking and update of the  blocked_list is done without dropping the
lock in between.

On the removal side, when waking up blocked lock waiters, take the
global lock before walking the blocked list and dequeue the waiters from
the global list prior to removal from the fl_block list.

With this, deadlock detection should be race free while we minimize
excessive file_lock_lock thrashing.

Finally, in order to avoid a lock inversion problem when handling
/proc/locks output we must ensure that manipulations of the fl_block
list are also protected by the file_lock_lock.

Signed-off-by: Jeff Layton 
Signed-off-by: Al Viro

ceph: ceph_pagelist_append might sleep while atomic

2013-05-17T17:45:48+00:00

Ceph's encode_caps_cb() worked hard to not call __page_cache_alloc()
while holding a lock, but it's spoiled because ceph_pagelist_addpage()
always calls kmap(), which might sleep.  Here's the result:

[13439.295457] ceph: mds0 reconnect start
[13439.300572] BUG: sleeping function called from invalid context at include/linux/highmem.h:58
[13439.309243] in_atomic(): 1, irqs_disabled(): 0, pid: 12059, name: kworker/1:1
    . . .
[13439.376225] Call Trace:
[13439.378757]  [] __might_sleep+0xfc/0x110
[13439.384353]  [] ceph_pagelist_append+0x120/0x1b0 [libceph]
[13439.391491]  [] ceph_encode_locks+0x89/0x190 [ceph]
[13439.398035]  [] ? _raw_spin_lock+0x49/0x50
[13439.403775]  [] ? lock_flocks+0x15/0x20
[13439.409277]  [] encode_caps_cb+0x41f/0x4a0 [ceph]
[13439.415622]  [] ? igrab+0x28/0x70
[13439.420610]  [] ? iterate_session_caps+0xe8/0x250 [ceph]
[13439.427584]  [] iterate_session_caps+0x115/0x250 [ceph]
[13439.434499]  [] ? set_request_path_attr+0x2d0/0x2d0 [ceph]
[13439.441646]  [] send_mds_reconnect+0x238/0x450 [ceph]
[13439.448363]  [] ? ceph_mdsmap_decode+0x5e2/0x770 [ceph]
[13439.455250]  [] check_new_map+0x352/0x500 [ceph]
[13439.461534]  [] ceph_mdsc_handle_map+0x1bd/0x260 [ceph]
[13439.468432]  [] ? mutex_unlock+0xe/0x10
[13439.473934]  [] extra_mon_dispatch+0x22/0x30 [ceph]
[13439.480464]  [] dispatch+0xbc/0x110 [libceph]
[13439.486492]  [] process_message+0x1ad/0x1d0 [libceph]
[13439.493190]  [] ? read_partial_message+0x3e8/0x520 [libceph]
    . . .
[13439.587132] ceph: mds0 reconnect success
[13490.720032] ceph: mds0 caps stale
[13501.235257] ceph: mds0 recovery completed
[13501.300419] ceph: mds0 caps renewed

Fix it up by encoding locks into a buffer first, and when the number
of encoded locks is stable, copy that into a ceph_pagelist.

[elder@inktank.com: abbreviated the stack info a bit.]

Cc: stable@vger.kernel.org # 3.4+
Signed-off-by: Jim Schutt 
Reviewed-by: Alex Elder