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>

ceph_check_caps() requests new max size only when there is Fw cap.
If we call check_max_size() while there is no Fw cap. It updates
i_wanted_max_size and calls ceph_check_caps(), but ceph_check_caps()
does nothing. Later when Fw cap is issued, we call check_max_size()
again. But i_wanted_max_size is equal to 'endoff' at this time, so
check_max_size() doesn't call ceph_check_caps() and we end up with
waiting for the new max size forever.

The fix is duplicate ceph_check_caps()'s "request max size" code in
check_max_size(), and make try_get_cap_refs() wait for the Fw cap
before retry requesting new max size.

This patch also removes the "endoff > (inode->i_size << 1)" check
in check_max_size(). It's useless because there is no corresponding
logic in ceph_check_caps().
Reviewed-by: NSage Weil <sage@inktank.com>
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

I encountered below deadlock when running fsstress

wmtruncate work      truncate                 MDS
---------------  ------------------  --------------------------
                   lock i_mutex
                                      <- truncate file
lock i_mutex (blocked)
                                      <- revoking Fcb (filelock to MIX)
                   send request ->
                                         handle request (xlock filelock)

At the initial time, there are some dirty pages in the page cache.
When the kclient receives the truncate message, it reduces inode size
and creates some 'out of i_size' dirty pages. wmtruncate work can't
truncate these dirty pages because it's blocked by the i_mutex. Later
when the kclient receives the cap message that revokes Fcb caps, It
can't flush all dirty pages because writepages() only flushes dirty
pages within the inode size.

When the MDS handles the 'truncate' request from kclient, it waits
for the filelock to become stable. But the filelock is stuck in
unstable state because it can't finish revoking kclient's Fcb caps.

The truncate pagecache locking has already caused lots of trouble
for use. I think it's time simplify it by introducing a new mutex.
We use the new mutex to prevent concurrent truncate_inode_pages().
There is no need to worry about race between buffered write and
truncate_inode_pages(), because our "get caps" mechanism prevents
them from concurrent execution.
Reviewed-by: NSage Weil <sage@inktank.com>
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

The MDS uses caps message to notify clients about deleted inode.
when receiving a such message, invalidate any alias of the inode.
This makes the kernel release the inode ASAP.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

If we receive new caps from the auth MDS and the non-auth MDS is
revoking the newly issued caps, we should release the caps from
the non-auth MDS. The scenario is filelock's state changes from
SYNC to LOCK. Non-auth MDS revokes Fc cap, the client gets Fc cap
from the auth MDS at the same time.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

If caps are been revoking by the auth MDS, don't consider them as
issued even they are still issued by non-auth MDS. The non-auth
MDS should also be revoking/exporting these caps, the client just
hasn't received the cap revoke/export message.

The race I encountered is: When caps are exporting to new MDS, the
client receives cap import message and cap revoke message from the
new MDS, then receives cap export message from the old MDS. When
the client receives cap revoke message from the new MDS, the revoking
caps are still issued by the old MDS, so the client does nothing.
Later when the cap export message is received, the client removes
the caps issued by the old MDS. (Another way to fix the race is
calling ceph_check_caps() in handle_cap_export())
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

The locking order for pending vmtruncate is wrong, it can lead to
following race:

        write                  wmtruncate work
------------------------    ----------------------
lock i_mutex
check i_truncate_pending   check i_truncate_pending
truncate_inode_pages()     lock i_mutex (blocked)
copy data to page cache
unlock i_mutex
                           truncate_inode_pages()

The fix is take i_mutex before calling __ceph_do_pending_vmtruncate()

Fixes: http://tracker.ceph.com/issues/5453Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

Drop ignored return value.  Fix allocation failure case to not leak.
Signed-off-by: NJianpeng Ma <majianpeng@gmail.com>
Reviewed-by: NSage Weil <sage@inktank.com>

Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

We may receive old request reply from the exporter MDS after receiving
the importer MDS' cap import message.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

ceph_encode_inode_release() can race with ceph_open() and release
caps wanted by open files. So it should call __ceph_caps_wanted()
to get the wanted caps.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

There is deadlock as illustrated bellow. The fix is taking i_mutex
before getting Fw cap reference.

      write                    truncate                 MDS
---------------------     --------------------      --------------
get Fw cap
                          lock i_mutex
lock i_mutex (blocked)
                          request setattr.size  ->
                                                <-   revoke Fw cap
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

Current ceph code tracks directory's completeness in two places.
ceph_readdir() checks i_release_count to decide if it can set the
I_COMPLETE flag in i_ceph_flags. All other places check the I_COMPLETE
flag. This indirection introduces locking complexity.

This patch adds a new variable i_complete_count to ceph_inode_info.
Set i_release_count's value to it when marking a directory complete.
By comparing the two variables, we know if a directory is complete
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>

commit c6ffe100 moved the flag that tracks if the dcache contents
for a directory are complete to dentry. The problem is there are
lots of places that use ceph_dir_{set,clear,test}_complete() while
holding i_ceph_lock. but ceph_dir_{set,clear,test}_complete() may
sleep because they call dput().

This patch basically reverts that commit. For ceph_d_prune(), it's
called with both the dentry to prune and the parent dentry are
locked. So it's safe to access the parent dentry's d_inode and
clear I_COMPLETE flag.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NGreg Farnum <greg@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

MDS ignores cap update message if migrate_seq mismatch, so when
receiving a cap import message with higher migrate_seq, set mds_want
according to the cap import message.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NGreg Farnum <greg@inktank.com>

So the client will later send cap release message to MDS
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NGreg Farnum <greg@inktank.com>

Before printing kuid and kgids values convert them into
the initial user namespace.

Cc: Sage Weil <sage@inktank.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

- Make the uid and gid arguments of send_cap_msg() used to compose
  ceph_mds_caps messages of type kuid_t and kgid_t.

- Pass inode->i_uid and inode->i_gid in __send_cap to send_cap_msg()
  through variables of type kuid_t and kgid_t.

- Modify struct ceph_cap_snap to store uids and gids in types kuid_t
  and kgid_t.  This allows capturing inode->i_uid and inode->i_gid in
  ceph_queue_cap_snap() without loss and pssing them to
  __ceph_flush_snaps() where they are removed from struct
  ceph_cap_snap and passed to send_cap_msg().

- In handle_cap_grant translate uid and gids in the initial user
  namespace stored in struct ceph_mds_cap into kuids and kgids
  before setting inode->i_uid and inode->i_gid.

Cc: Sage Weil <sage@inktank.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

The MDS may have incorrect wanted caps after importing caps. So the
client should check the value mds has and send cap update if necessary.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

When client wants to release an imported cap, it's possible there
is no reserved cap_release message in corresponding mds session.
so __queue_cap_release causes kernel panic.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

Allow revoking duplicated caps issued by non-auth MDS if these caps
are also issued by auth MDS.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: NSage Weil <sage@inktank.com>

If client sends cap message that requests new max size during
exporting caps, the exporting MDS will drop the message quietly.
So the client may wait for the reply that updates the max size
forever. call handle_cap_grant() for cap import message can
avoid this issue.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: NSage Weil <sage@inktank.com>

Add dirty inode to cap_dirty_migrating list instead, this can avoid
ceph_flush_dirty_caps() entering infinite loop.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: NSage Weil <sage@inktank.com>

The cap from non-auth mds doesn't have a meaningful max_size value.
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: NSage Weil <sage@inktank.com>

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

Convert cpu_to_le32(le32_to_cpu(E1) + E2) to use le32_add_cpu().

dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch)
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NSage Weil <sage@inktank.com>

Lockdep was reporting a possible circular lock dependency in
dentry_lease_is_valid().  That function needs to sample the
session's s_cap_gen and and s_cap_ttl fields coherently, but needs
to do so while holding a dentry lock.  The s_cap_lock field was
being used to protect the two fields, but that can't be taken while
holding a lock on a dentry within the session.

In most cases, the s_cap_gen and s_cap_ttl fields only get operated
on separately.  But in three cases they need to be updated together.
Implement a new lock to protect the spots updating both fields
atomically is required.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Reviewed-by: NSage Weil <sage@newdream.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We have been using i_lock to protect all kinds of data structures in the
ceph_inode_info struct, including lists of inodes that we need to iterate
over while avoiding races with inode destruction.  That requires grabbing
a reference to the inode with the list lock protected, but igrab() now
takes i_lock to check the inode flags.

Changing the list lock ordering would be a painful process.

However, using a ceph-specific i_ceph_lock in the ceph inode instead of
i_lock is a simple mechanical change and avoids the ordering constraints
imposed by igrab().
Reported-by: NAmon Ott <a.ott@m-privacy.de>
Signed-off-by: NSage Weil <sage@newdream.net>

We used to use a flag on the directory inode to track whether the dcache
contents for a directory were a complete cached copy.  Switch to a dentry
flag CEPH_D_COMPLETE that is safely updated by ->d_prune().
Signed-off-by: NSage Weil <sage@newdream.net>

Replace remaining direct i_nlink updates with a new set_nlink()
updater function.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Tested-by: NToshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The pool allocation failures are masked by the pool; there is no need to
spam the console about them.  (That's the whole point of having the pool
in the first place.)

Mark msg allocations whose failure is safely handled as such.
Signed-off-by: NSage Weil <sage@newdream.net>

Btrfs needs to be able to control how filemap_write_and_wait_range() is called
in fsync to make it less of a painful operation, so push down taking i_mutex and
the calling of filemap_write_and_wait() down into the ->fsync() handlers.  Some
file systems can drop taking the i_mutex altogether it seems, like ext3 and
ocfs2.  For correctness sake I just pushed everything down in all cases to make
sure that we keep the current behavior the same for everybody, and then each
individual fs maintainer can make up their mind about what to do from there.
Thanks,
Acked-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We should use ihold whenever we already have a stable inode ref, even
when we aren't holding i_lock.  This avoids adding new and unnecessary
locking dependencies.
Signed-off-by: NSage Weil <sage@newdream.net>

In e9964c10 we change cap flushing to do a delicate dance because some
inodes on the cap_dirty list could be in a migrating state (got EXPORT but
not IMPORT) in which we couldn't actually flush and move from
dirty->flushing, breaking the while (!empty) { process first } loop
structure.  It worked for a single sync thread, but was not reentrant and
triggered infinite loops when multiple syncers came along.

Instead, move inodes with dirty to a separate cap_dirty_migrating list
when in the limbo export-but-no-import state, allowing us to go back to
the simple loop structure (which was reentrant).  This is cleaner and more
robust.

Audited the cap_dirty users and this looks fine:
list_empty(&ci->i_dirty_item) is still a reliable indicator of whether we
have dirty caps (which list we're on is irrelevant) and list_del_init()
calls still do the right thing.
Signed-off-by: NSage Weil <sage@newdream.net>

If we grab new_cap, retake the lock, and find we already have a cap now
for the given mds, release new_cap.
Signed-off-by: NSage Weil <sage@newdream.net>

We increments i_wrbuffer_ref when taking the Fb cap. This breaks
the dirty page accounting and causes looping in
__ceph_do_pending_vmtruncate, and ceph client hangs.

This bug can be reproduced occasionally by running blogbench.

Add a new field i_wb_ref to inode and dedicate it to Fb reference
counting.
Signed-off-by: NHenry C Chang <henry.cy.chang@gmail.com>
Signed-off-by: NSage Weil <sage@newdream.net>

The __mark_dirty_inode helper now takes i_lock as of 250df6ed.  Fix the
one ceph callers that held i_lock (__ceph_mark_dirty_caps) to return the
flags value so that the callers can do it outside of i_lock.
Signed-off-by: NSage Weil <sage@newdream.net>