If we have enough memory to allocate a new cap release message, do so, so
that we can send a partial release message immediately.  This keeps us from
making the MDS wait when the cap release it needs is in a partially full
release message.

If we fail because of ENOMEM, oh well, they'll just have to wait a bit
longer.
Signed-off-by: NSage Weil <sage@newdream.net>

If we get an IMPORT that give us a cap, but we don't have the inode, queue
a release (and try to send it immediately) so that the MDS doesn't get
stuck waiting for us.
Signed-off-by: NSage Weil <sage@newdream.net>

Nothing is released here: the caps message is simply ignored in this case.
Signed-off-by: NSage Weil <sage@newdream.net>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This is essential, as for the rados block device we'll need
to run in different contexts that would need flags that
are other than GFP_NOFS.
Signed-off-by: NYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

We don't ever use "dirty" so we can remove it.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NSage Weil <sage@newdream.net>

We only need to pass in front_len.  Callers can attach any other payload
pieces (middle, data) as they see fit.
Signed-off-by: NSage Weil <sage@newdream.net>

Returning ERR_PTR(-ENOMEM) is useless extra work.  Return NULL on failure
instead, and fix up the callers (about half of which were wrong anyway).
Signed-off-by: NSage Weil <sage@newdream.net>

ceph_sb_to_client and ceph_client are really identical, we need to dump
one; while function ceph_client is confusing with "struct ceph_client",
ceph_sb_to_client's definition is more clear; so we'd better switch all
call to ceph_sb_to_client.

  -static inline struct ceph_client *ceph_client(struct super_block *sb)
  -{
  -	return sb->s_fs_info;
  -}
Signed-off-by: NCheng Renquan <crquan@gmail.com>
Signed-off-by: NSage Weil <sage@newdream.net>

The iterate_session_caps helper traverses the session caps list and tries
to grab an inode reference.  However, the __ceph_remove_cap was clearing
the inode backpointer _before_ removing itself from the session list,
causing a null pointer dereference.

Clear cap->ci under protection of s_cap_lock to avoid the race, and to
tightly couple the list and backpointer state.  Use a local flag to
indicate whether we are releasing the cap, as cap->session may be modified
by a racing thread in iterate_session_caps.
Signed-off-by: NSage Weil <sage@newdream.net>

Signed-off-by: NSage Weil <sage@newdream.net>

We create a ceph_cap_snap if there is dirty cap metadata (for writeback to
mds) OR dirty pages (for writeback to osd).  It is thus possible that the
metadata has been written back to the MDS but the OSD data has not when
the cap_snap is created.  This results in a cap_snap with dirty(caps) == 0.
The problem is that cap writeback to the MDS isn't necessary, and a
FLUSHSNAP cap op gets no ack from the MDS.  This leaves the cap_snap
attached to the inode along with its inode reference.

Fix the problem by dropping the cap_snap if it becomes 'complete' (all
pages written out) and dirty(caps) == 0 in ceph_put_wrbuffer_cap_refs().

Also, BUG() in __ceph_flush_snaps() if we encounter a cap_snap with
dirty(caps) == 0.
Signed-off-by: NSage Weil <sage@newdream.net>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

We were releasing used caps (e.g. FILE_CACHE) from encode_inode_release
with MDS requests (e.g. setattr).  We don't carry refs on most caps, so
this code worked most of the time, but for setattr (utimes) we try to
drop Fscr.

This causes cap state to get slightly out of sync with reality, and may
result in subsequent mds revoke messages getting ignored.

Fix by only releasing unused caps.
Signed-off-by: NSage Weil <sage@newdream.net>

Drop session mutex unconditionally in handle_cap_grant, and do the
check_caps from the handle_cap_grant helper.  This avoids using a magic
return value.

Also avoid using a flag variable in the IMPORT case and call
check_caps at the appropriate point.
Signed-off-by: NSage Weil <sage@newdream.net>

Passing a session pointer to ceph_check_caps() used to mean it would leave
the session mutex locked.  That wasn't always possible if it wasn't passed
CHECK_CAPS_AUTHONLY.   If could unlock the passed session and lock a
differet session mutex, which was clearly wrong, and also emitted a
warning when it a racing CPU retook it and we did an unlock from the wrong
context.

This was only a problem when there was more than one MDS.

First, make ceph_check_caps unconditionally drop the session mutex, so that
it is free to lock other sessions as needed.  Then adjust the one caller
that passes in a session (handle_cap_grant) accordingly.
Signed-off-by: NSage Weil <sage@newdream.net>

If we don't have the exported cap it's because we already released it. No
need to WARN.
Signed-off-by: NSage Weil <sage@newdream.net>

Added assertion, and cleared one case where the implemented caps were
not following the issued caps.
Signed-off-by: NYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NSage Weil <sage@newdream.net>

The flush_dirty_caps() used to loop over the first entry of the cap_dirty
dirty list on the assumption that after calling ceph_check_caps() it would
be removed from the list.  This isn't true for caps that are being
migrated between MDSs, where we've received the EXPORT but not the IMPORT.

Instead, do a safe list iteration, and pin the next inode on the list via
the CEPH_I_NOFLUSH flag.
Signed-off-by: NSage Weil <sage@newdream.net>

We should include caps that are mid-migration (we've received the EXPORT,
but not the IMPORT) in the issued caps set.
Signed-off-by: NSage Weil <sage@newdream.net>

Verify the file is actually open for the given caps when we are
waiting for caps.  This ensures we will wake up and return EBADF
if another thread closes the file out from under us.

Note that EBADF is also the correct return code from write(2)
when called on a file handle opened for reading (although the
vfs should catch that).
Signed-off-by: NSage Weil <sage@newdream.net>

This was simply broken.  Apparently at some point we thought about putting
the snaptrace in the middle section, but didn't.
Signed-off-by: NSage Weil <sage@newdream.net>

Verify the mds session is currently registered before handling
incoming messages.  Clean up message handlers to pull mds out
of session->s_mds instead of less trustworthy src field.

Clean up con_{get,put} debug output.
Signed-off-by: NSage Weil <sage@newdream.net>

The destroy_inode path needs no inode locks since there are no
inode references.  Update __ceph_remove_cap comment to reflect
that it is called without cap->session->s_mutex in this case.
Signed-off-by: NSage Weil <sage@newdream.net>

There is no state in local vars that requires us to loop after temporarily
dropping i_lock.
Signed-off-by: NYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

We need to know whether there was any page left behind, and not the
return value (the total number of pages invalidated).  Look at the mapping
to see if we were successful or not.

Move it all into a helper to simplify the two callers.
Signed-off-by: NYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

We need to be able to iterate over all caps on a session with a
possibly slow callback on each cap.  To allow this, we used to
prevent cap reordering while we were iterating.  However, we were
not safe from races with removal: removing the 'next' cap would
make the next pointer from list_for_each_entry_safe be invalid,
and cause a lock up or similar badness.

Instead, we keep an iterator pointer in the session pointing to
the current cap.  As before, we avoid reordering.  For removal,
if the cap isn't the current cap we are iterating over, we are
fine.  If it is, we clear cap->ci (to mark the cap as pending
removal) but leave it in the session list.  In iterate_caps, we
can safely finish removal and get the next cap pointer.

While we're at it, clean up put_cap to not take a cap reservation
context, as it was never used.
Signed-off-by: NSage Weil <sage@newdream.net>

Use a global counter for the minimum number of allocated caps instead of
hard coding a check against readdir_max.  This takes into account multiple
client instances, and avoids examining the superblock mount options when a
cap is dropped.
Signed-off-by: NSage Weil <sage@newdream.net>

We were invalidating mapping pages when dropping FILE_CACHE in
__send_cap().  But ceph_check_caps attempts to invalidate already, and
also checks for success, so we should never get to this point.
Signed-off-by: NSage Weil <sage@newdream.net>

There is no reason not to invalidate pages when a truncate is pending.
Both throw out page cache pages.
Signed-off-by: NSage Weil <sage@newdream.net>

Grab inode ref in helper.  Make work functions static, with consistent
naming.
Signed-off-by: NSage Weil <sage@newdream.net>

Never retain caps in __send_cap() that are being revoked.
Signed-off-by: NSage Weil <sage@newdream.net>

Try to invalidate pages in ceph_check_caps() if FILE_CACHE is being
revoked.  If we fail, queue an immediate async invalidate if FILE_CACHE
is being revoked.  (If it's not being revoked, we just queue the caps
for later evaluation later, as per the old behavior.)
Signed-off-by: NSage Weil <sage@newdream.net>

Many (most?) message types include a transaction id.  By including it in
the fixed size header, we always have it available even when we are unable
to allocate memory for the (larger, variable sized) message body.  This
will allow us to error out the appropriate request instead of (silently)
dropping the reply.
Signed-off-by: NSage Weil <sage@newdream.net>

Avoid confusing iterate_session_caps(), flag the session while we are
iterating so that __touch_cap does not rearrange items on the list.

All other modifiers of session->s_caps do so under the protection of
s_mutex.
Signed-off-by: NSage Weil <sage@newdream.net>

Also, print fsid using standard format, NOT hex dump.
Signed-off-by: NSage Weil <sage@newdream.net>

Signed-off-by: NSage Weil <sage@newdream.net>

We occasionally want to make a best-effort attempt to invalidate cache
pages without fear of blocking.  If this fails, we fall back to an async
invalidate in another thread.

Use invalidate_mapping_pages instead of invalidate_inode_page2, as that
will skip locked pages, and not deadlock.
Signed-off-by: NSage Weil <sage@newdream.net>

We don't get an explicit affirmative confirmation that our caps reconnect,
nor do we necessarily want to pay that cost.  So, take all this code out
for now.
Signed-off-by: NSage Weil <sage@newdream.net>