In most cases that snap context is needed, we are holding
reference of CEPH_CAP_FILE_WR. So we can set ceph inode's
i_head_snapc when getting the CEPH_CAP_FILE_WR reference,
and make codes get snap context from i_head_snapc. This makes
the code simpler.

Another benefit of this change is that we can handle snap
notification more elegantly. Especially when snap context
is updated while someone else is doing write. The old queue
cap_snap code may set cap_snap's context to ether the old
context or the new snap context, depending on if i_head_snapc
is set. The new queue capp_snap code always set cap_snap's
context to the old snap context.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

Signed-off-by: NYan, Zheng <zyan@redhat.com>

If a directory is complete, we want to keep the exclusive
cap. So that MDS does not end up revoking the shared cap
on every create/unlink operation.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

No i_auth_cap means reconnecting to MDS was denied. So don't
add new dirty caps.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

when reconnecting to MDS is denied, we remove session caps
forcibly. But it's possible there are ongoing write, the
write code needs to reference i_snap_realm. So if there are
ongoing write, we keep i_snap_realm.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

that's the bulk of filesystem drivers dealing with inodes of their own
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

we should not do block operation in wait_event_interruptible()'s condition
check function, but reading inline data can block. so move the read inline
data code to ceph_get_caps()
Signed-off-by: NYan, Zheng <zyan@redhat.com>

check_cap_flush() calls mutex_lock(), which may block. So we can't
use it as condition check function for wait_event();
Signed-off-by: NYan, Zheng <zyan@redhat.com>

When snaprealm is created, its initial reference count is zero.
But in some rare cases, the newly created snaprealm is not referenced
by anyone. This causes snaprealm with zero reference count not freed.

The fix is set reference count of newly snaprealm to 1. The reference
is return the function who requests to create the snaprealm. When the
function finishes its job, it releases the reference.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

mark session as readonly and wake up all cap waiters.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

After converting inline data to normal data, client need to flush
the new i_inline_version (CEPH_INLINE_NONE) to MDS. This commit makes
cap messages (sent to MDS) contain inline_version and inline_data.
Client always converts inline data to normal data before data write,
so the inline data length part is always zero.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

we can't use getattr to fetch inline data after getting Fcr caps,
because it can cause deadlock. The solution is try bringing inline
data to page cache when not holding any cap, and hope the inline
data page is still there after getting the Fcr caps. If the page
is still there, pin it in page cache for later IO.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

Request reply and cap message can contain inline data. add inline data
to the page cache if there is Fc cap.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

Signed-off-by: NYan, Zheng <zyan@redhat.com>

The functions ceph_put_snap_context() and iput() test whether their
argument is NULL and then return immediately. Thus the test around the
call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
[idryomov@redhat.com: squashed rbd.c hunk, changelog]
Signed-off-by: NIlya Dryomov <idryomov@redhat.com>

TID of cap flush ack is 64 bits, but ceph_inode_info::flushing_cap_tid
is only 16 bits. 16 bits should be plenty to let the cap flush updates
pipeline appropriately, but we need to cast in the proper direction when
comparing these differently-sized versions. So downcast the 64-bits one
to 16 bits.

Reflects ceph.git commit a5184cf46a6e867287e24aeb731634828467cd98.
Signed-off-by: NYan, Zheng <zyan@redhat.com>
Reviewed-by: NIlya Dryomov <idryomov@redhat.com>

Fix some coccinelle warnings:
fs/ceph/caps.c:2400:6-10: WARNING: Assignment of bool to 0/1
fs/ceph/caps.c:2401:6-15: WARNING: Assignment of bool to 0/1
fs/ceph/caps.c:2402:6-17: WARNING: Assignment of bool to 0/1
fs/ceph/caps.c:2403:6-22: WARNING: Assignment of bool to 0/1
fs/ceph/caps.c:2404:6-22: WARNING: Assignment of bool to 0/1
fs/ceph/caps.c:2405:6-19: WARNING: Assignment of bool to 0/1
fs/ceph/caps.c:2440:4-20: WARNING: Assignment of bool to 0/1
fs/ceph/caps.c:2469:3-16: WARNING: Assignment of bool to 0/1
fs/ceph/caps.c:2490:2-18: WARNING: Assignment of bool to 0/1
fs/ceph/caps.c:2519:3-7: WARNING: Assignment of bool to 0/1
fs/ceph/caps.c:2549:3-12: WARNING: Assignment of bool to 0/1
fs/ceph/caps.c:2575:2-6: WARNING: Assignment of bool to 0/1
fs/ceph/caps.c:2589:3-7: WARNING: Assignment of bool to 0/1
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NIlya Dryomov <idryomov@redhat.com>

ceph_find_inode() may wait on freeing inode, using it inside the s_mutex
may cause deadlock. (the freeing inode is waiting for OSD read reply, but
dispatch thread is blocked by the s_mutex)
Signed-off-by: NYan, Zheng <zyan@redhat.com>
Reviewed-by: NSage Weil <sage@redhat.com>

Replace a comma between expression statements by a semicolon. This changes
the semantics of the code, but given the current indentation appears to be
what is intended.

A simplified version of the Coccinelle semantic patch that performs this
transformation is as follows:
// <smpl>
@r@
expression e1,e2;
@@

 e1
-,
+;
 e2;
// </smpl>
Signed-off-by: NHimangi Saraogi <himangi774@gmail.com>
Acked-by: NJulia Lawall <julia.lawall@lip6.fr>
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>

handle following sequence of events:
- mds0 exports an inode to mds1. client receives the cap import
  message from mds1. caps from mds0 are removed while handling
  the cap import message.
- mds1 exports an inode to mds0. client receives the cap export
  message from mds1. handle_cap_export() adds placeholder caps
  for mds0
- client receives the first cap export message (for exporting
  inode from mds0 to mds1)
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

cap import messages are processed by both handle_cap_import() and
handle_cap_grant(). These two functions are not executed in the same
atomic context, so they can races with cap release.

The fix is make handle_cap_import() not release the i_ceph_lock when
it returns. Let handle_cap_grant() release the lock after it finishes
its job.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

So that ceph_add_cap() can be used while i_ceph_lock is locked.
This simplifies the code that handle cap import/export.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

Cap message and request reply from non-auth MDS may carry stale
information (corresponding locks are in LOCK states) even they
have the newest inode version. So client should update inode fields
according to issued caps.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

cap grant/revoke message from non-auth MDS can update inode's size
and truncate_seq/truncate_size. (the message arrives before auth
MDS's cap trunc message)
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

To avoid releasing caps that are being used, encode_inode_release()
should send implemented caps to MDS.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

When adjusting caps client wants, MDS does not record caps that are
not allowed. For non-auth MDS, it does not record WR caps. So when
a MDS reply changes a non-auth cap to auth cap, client needs to set
cap's mds_wanted according to the reply.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

Only auth MDS can issue write caps to clients, so don't consider
write caps registered with non-auth MDS as valid.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

Version 3 cap export message includes information about the imported
caps. It allows us to add the imported caps if the corresponding cap
import message still hasn't been received.

This allow us to handle situation that the importer MDS crashes and
the cap import message is missing.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

Version 3 cap import message includes the ID of the exported
caps. It allow us to remove the exported caps if we still haven't
received the corresponding cap export message.

We remove the exported caps because they are stale, keeping them
can compromise consistence.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

Some inodes in readdir reply may have no caps. Getattr mds request
for these inodes can return -ESTALE. The fix is consider dentry that
links to inode with no caps as invalid. Invalid dentry causes a
lookup request to send to the mds, the MDS will send caps back.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

handle following sequence of events:

- non-auth MDS revokes Fc cap. queue invalidate work
- auth MDS issues Fc cap through request reply. i_rdcache_gen gets
  increased.
- invalidate work runs. it finds i_rdcache_revoking != i_rdcache_gen,
  so it does nothing.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

auth cap may change after releasing the i_ceph_lock
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

"disconnected" is too easily confused with "DCACHE_DISCONNECTED".  I
think "unhashed" is the more precise term here.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
Reviewed-by: NSage Weil <sage@inktank.com>

Signed-off-by: NGuangliang Zhao <lucienchao@gmail.com>
Reviewed-by: NLi Wang <li.wang@ubuntykylin.com>
Reviewed-by: NZheng Yan <zheng.z.yan@intel.com>

When a cap get released while composing the cap reconnect message.
We should skip queuing the release message if the cap hasn't been
added to the cap reconnect message.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

call __queue_cap_release() in __ceph_remove_cap(), this avoids
acquiring s_cap_lock twice.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

d_invalidate() is the standard VFS method to invalidate dentry.
compare to d_delete(), it also try shrinking children dentries.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

Adding support for fscache to the Ceph filesystem. This would bring it to on
par with some of the other network filesystems in Linux (like NFS, AFS, etc...)

In order to mount the filesystem with fscache the 'fsc' mount option must be
passed.
Signed-off-by: NMilosz Tanski <milosz@adfin.com>
Signed-off-by: NSage Weil <sage@inktank.com>

Cleanup in handle_cap_grant().
Signed-off-by: NLi Wang <liwang@ubuntukylin.com>
Reviewed-by: NSage Weil <sage@inktank.com>