Accessing d_parent requires some sort of locking or it could vanish
out from under us. Since we take the d_lock anyway, use that to fetch
d_parent and take a reference to it, and then use that reference to
call ceph_encode_inode_release.

Link: http://tracker.ceph.com/issues/18148Signed-off-by: NJeff Layton <jlayton@redhat.com>
Reviewed-by: NYan, Zheng <zyan@redhat.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Commit 5c341ee3 ("ceph: fix scheduler warning due to nested
blocking") causes infinite loop when process is interrupted.  Fix it.
Signed-off-by: NYan, Zheng <zyan@redhat.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

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

Add a flags parameter to send_cap_msg, so we can request expedited
service from the MDS when we know we'll be waiting on the result.

Set that flag in the case of try_flush_caps. The callers of that
function generally wait synchronously on the result, so it's beneficial
to ask the server to expedite it.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Reviewed-by: NYan, Zheng <zyan@redhat.com>

The userland ceph has MClientCaps at struct version 10. This brings the
kernel up the same version.

For now, all of the the new stuff is set to default values including
the flags field, which will be conditionally set in a later patch.

Note that we don't need to set the change_attr and btime to anything
since we aren't currently setting the feature flag. The MDS should
ignore those values.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Reviewed-by: NYan, Zheng <zyan@redhat.com>

When we get to this many arguments, it's hard to work with positional
parameters. send_cap_msg is already at 25 arguments, with more needed.

Define a new args structure and pass a pointer to it to send_cap_msg.
Eventually it might make sense to embed one of these inside
ceph_cap_snap instead of tracking individual fields.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Reviewed-by: NYan, Zheng <zyan@redhat.com>

Just for clarity. This part is inside the header, so it makes sense to
group it with the rest of the stuff in the header.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Reviewed-by: NYan, Zheng <zyan@redhat.com>

Signed-off-by: NJeff Layton <jlayton@redhat.com>
Reviewed-by: NYan, Zheng <zyan@redhat.com>

For readahead/fadvise cases, caller of ceph_readpages does not
hold buffer capability. Pages can be added to page cache while
there is no buffer capability. This can cause data integrity
issue.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

try_get_cap_refs can be used as a condition in a wait_event* calls.
This is all fine until it has to call __ceph_do_pending_vmtruncate,
which in turn acquires the i_truncate_mutex. This leads to a situation
in which a task's state is !TASK_RUNNING and at the same time it's
trying to acquire a sleeping primitive. In essence a nested sleeping
primitives are being used. This causes the following warning:

WARNING: CPU: 22 PID: 11064 at kernel/sched/core.c:7631 __might_sleep+0x9f/0xb0()
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8109447d>] prepare_to_wait_event+0x5d/0x110
 ipmi_msghandler tcp_scalable ib_qib dca ib_mad ib_core ib_addr ipv6
CPU: 22 PID: 11064 Comm: fs_checker.pl Tainted: G           O    4.4.20-clouder2 #6
Hardware name: Supermicro X10DRi/X10DRi, BIOS 1.1a 10/16/2015
 0000000000000000 ffff8838b416fa88 ffffffff812f4409 ffff8838b416fad0
 ffffffff81a034f2 ffff8838b416fac0 ffffffff81052b46 ffffffff81a0432c
 0000000000000061 0000000000000000 0000000000000000 ffff88167bda54a0
Call Trace:
 [<ffffffff812f4409>] dump_stack+0x67/0x9e
 [<ffffffff81052b46>] warn_slowpath_common+0x86/0xc0
 [<ffffffff81052bcc>] warn_slowpath_fmt+0x4c/0x50
 [<ffffffff8109447d>] ? prepare_to_wait_event+0x5d/0x110
 [<ffffffff8109447d>] ? prepare_to_wait_event+0x5d/0x110
 [<ffffffff8107767f>] __might_sleep+0x9f/0xb0
 [<ffffffff81612d30>] mutex_lock+0x20/0x40
 [<ffffffffa04eea14>] __ceph_do_pending_vmtruncate+0x44/0x1a0 [ceph]
 [<ffffffffa04fa692>] try_get_cap_refs+0xa2/0x320 [ceph]
 [<ffffffffa04fd6f5>] ceph_get_caps+0x255/0x2b0 [ceph]
 [<ffffffff81094370>] ? wait_woken+0xb0/0xb0
 [<ffffffffa04f2c11>] ceph_write_iter+0x2b1/0xde0 [ceph]
 [<ffffffff81613f22>] ? schedule_timeout+0x202/0x260
 [<ffffffff8117f01a>] ? kmem_cache_free+0x1ea/0x200
 [<ffffffff811b46ce>] ? iput+0x9e/0x230
 [<ffffffff81077632>] ? __might_sleep+0x52/0xb0
 [<ffffffff81156147>] ? __might_fault+0x37/0x40
 [<ffffffff8119e123>] ? cp_new_stat+0x153/0x170
 [<ffffffff81198cfa>] __vfs_write+0xaa/0xe0
 [<ffffffff81199369>] vfs_write+0xa9/0x190
 [<ffffffff811b6d01>] ? set_close_on_exec+0x31/0x70
 [<ffffffff8119a056>] SyS_write+0x46/0xa0

This happens since wait_event_interruptible can interfere with the
mutex locking code, since they both fiddle with the task state.

Fix the issue by using the newly-added nested blocking infrastructure
in 61ada528 ("sched/wait: Provide infrastructure to deal with
nested blocking")

Link: https://lwn.net/Articles/628628/Signed-off-by: NNikolay Borisov <kernel@kyup.com>
Signed-off-by: NYan, Zheng <zyan@redhat.com>

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

Add a 'wake' flag to ceph_cap_flush struct, which indicates if there
is someone waiting for it to finish. When getting flush ack message,
we check the 'wake' flag in corresponding ceph_cap_flush struct to
decide if we should wake up waiters. One corner case is that the
acked cap flush has 'wake' flags is set, but it is not the first one
on the flushing list. We do not wake up waiters in this case, set
'wake' flags of preceding ceph_cap_flush struct instead
Signed-off-by: NYan, Zheng <zyan@redhat.com>

This patch devide __ceph_flush_snaps() into two stags. In the first
stage, __ceph_flush_snaps() assign snapcaps flush TIDs and add them
to cap flush lists. __ceph_flush_snaps() keeps holding the
i_ceph_lock in this stagge. So inode's auth cap can not change. In
the second stage, __ceph_flush_snaps() send flushsnap cap messages.
i_ceph_lock is unlocked before sending each cap message. If auth cap
changes in the middle, __ceph_flush_snaps() just stops. This is OK
because kick_flushing_inode_caps() will re-send flushsnap cap messages
to inode's new auth MDS.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

If ceph_check_caps() wants to send cap message to a recovering MDS,
make sure it kicks cap flushes first.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

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

make ceph_kick_flushing_caps() ignore inodes whose cap flushes
have already been re-sent by ceph_early_kick_flushing_caps()
Signed-off-by: NYan, Zheng <zyan@redhat.com>

This patch includes following changes
- Assign flush tid to snapcap flush
- Remove session's s_cap_snaps_flushing list. Add inode to session's
  s_cap_flushing list instead. Inode is removed from the list when
  there is no pending snapcap flush or cap flush.
- make __kick_flushing_caps() re-send both snapcap flushes and cap
  flushes.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

We don't have requirement of searching cap flush by TID. In most cases,
we just need to know TID of the oldest cap flush. List is ideal for this
usage.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

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

Otherwise ceph_sync_write_unsafe() may access/modify freed inode.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

Track usage count for individual fmode bit. This can reduce the
array size by half.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

This patch adds codes that decode pool namespace information in
cap message and request reply. Pool namespace is saved in i_layout,
it will be passed to libceph when doing read/write.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

Define new ceph_file_layout structure and rename old ceph_file_layout
to ceph_file_layout_legacy. This is preparation for adding namespace
to ceph_file_layout structure.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

There are several issues in fscache revalidation code.
- In ceph_revalidate_work(), fscache_invalidate() is called when
  fscache_check_consistency() return 0. This is complete wrong
  because 0 means cache is valid.
- Handle_cap_grant() calls ceph_queue_revalidate() if client
  already has CAP_FILE_CACHE. This code is confusing. Client
  should revalidate the cache each time it got CAP_FILE_CACHE
  anew.
- In Handle_cap_grant(), fscache_invalidate() is called if MDS
  revokes CAP_FILE_CACHE. This is inconsistency with the case
  that inode get evicted. In the later case, the cache is not
  discarded. Client may use the cache when inode is reloaded.

This patch moves the fscache revalidation into ceph_get_caps().
Client revalidates the cache after it gets CAP_FILE_CACHE.
i_rdcache_gen should keep constance while CAP_FILE_CACHE is
used. If i_fscache_gen is not equal to i_rdcache_gen, client
needs to check cache's consistency.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

ceph_fill_file_size() has already called ceph_fscache_invalidate()
if it return true.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

truncate_pagecache() drops dirty pages, it's dangerous to use it
to invalidate read cache. Besides, we shouldn't start invalidating
read cache while there are buffer writers. Because buffer writers
may add dirty pages later.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

When mds session gets killed, read/write operation may hang.
Client waits for Frw caps, but mds does not know what caps client
wants. To recover this, client sends an open request to mds. The
request will tell mds what caps client wants.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE.  And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special.  They are
not.

The changes are pretty straight-forward:

 - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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

Add support for the format change of MClientReply/MclientCaps.
Also add code that denies access to inodes with pool_ns layouts.
Signed-off-by: NYan, Zheng <zyan@redhat.com>
Reviewed-by: NSage Weil <sage@redhat.com>

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

If we get a unsafe reply for request that created/modified inode,
add the unsafe request to a list in the newly created/modified
inode. So we can make fsync() wait these unsafe requests.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

ceph_check_caps() invalidate page cache when inode is not used
by any open file. This behaviour is not friendly for workload
that repeatly read files.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

This patch makes try_get_cap_refs() and __do_request() check
if the file system was forced umount, and return -EIO if it was.
This patch also adds a helper function to drops dirty caps and
wakes up blocking operation.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

commit e548e9b9 makes the kclient
only re-send cap flush once during MDS failover. If the kclient sends
a cap flush after MDS enters reconnect stage but before MDS recovers.
The kclient will skip re-sending the same cap flush when MDS recovers.

This causes problem for newly created inode. The MDS handles cap
flushes before replaying unsafe requests, so it's possible that MDS
find corresponding inode is missing when handling cap flush. The fix
is reverting to old behaviour: always re-send when MDS recovers
Signed-off-by: NYan, Zheng <zyan@redhat.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Previously our dcache readdir code relies on that child dentries in
directory dentry's d_subdir list are sorted by dentry's offset in
descending order. When adding dentries to the dcache, if a dentry
already exists, our readdir code moves it to head of directory
dentry's d_subdir list. This design relies on dcache internals.
Al Viro suggests using ncpfs's approach: keeping array of pointers
to dentries in page cache of directory inode. the validity of those
pointers are presented by directory inode's complete and ordered
flags. When a dentry gets pruned, we clear directory inode's complete
flag in the d_prune() callback. Before moving a dentry to other
directory, we clear the ordered flag for both old and new directory.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

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

if flushing caps were revoked, we should re-send the cap flush in
client reconnect stage. This guarantees that MDS processes the cap
flush message before issuing the flushing caps to other client.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

According to this information, MDS can trim its completed caps flush
list (which is used to detect duplicated cap flush).
Signed-off-by: NYan, Zheng <zyan@redhat.com>

So we know TID of the oldest pending caps flushing. Later patch will
send this information to MDS, so that MDS can trim its completed caps
flush list.

Tracking pending caps flushing globally also simplifies syncfs code.
Signed-off-by: NYan, Zheng <zyan@redhat.com>