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>

An on-stack oid in ceph_ioctl_get_dataloc() is not initialized,
resulting in a WARN and a NULL pointer dereference later on.  We will
have more of these on-stack in the future, so fix it with a convenience
macro.

Fixes: d30291b9 ("libceph: variable-sized ceph_object_id")
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

->atomic_open() can be given an in-lookup dentry *or* a negative one
found in dcache.  Use d_in_lookup() to tell one from another, rather
than d_unhashed().
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

on failure d_obtain_alias() will have done iput()
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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>

All other filesystems do not add dirty pages to fscache. They all
disable fscache when inode is opened for write. Only ceph adds
dirty pages to fscache, but the code is buggy.
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>

If readpages fails, fscache needs to cleanup its internal state.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

For the benefit of every single caller, take osdc instead of map.
Also, now that osdc->osdmap can't ever be NULL, drop the check.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

preparation for similar switch in ->setxattr() (see the next commit for
rationale).
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We should reset i_requested_max_size before waking the waiters.
(zero i_requested_max_size make waiter re-request the max size)
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>

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

writepage() can be interrupted when it's called by direct memory
reclaimer (the direct memory relaimer is killed). To avoid lossing
data, we redirty the page.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

ceph_update_writeable_page() is used by ceph_write_begin(). It beaks
atomicity of write operation if it's interruptible.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

when ceph_update_writeable_page() return -EAGAIN, caller should
lock the page and call ceph_update_writeable_page() again.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

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

Fault and page_mkwrite are supposed to be uninterruptable. But they
call ceph functions that are interruptible. So they should block
signals before calling functions that are interruptible
Signed-off-by: NYan, Zheng <zyan@redhat.com>

This patch makes serverl logical caculation functions return bool to
improve readability due to these particular functions only using 0/1
as their return value.

No functional change.
Signed-off-by: NZhang Zhuoyu <zhangzhuoyu@cmss.chinamobile.com>

A mds bug can cause symlink's size to be truncated to zero.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

check if number of splits in i_fragtree is equal to number of splits
in mds reply
Signed-off-by: NYan, Zheng <zyan@redhat.com>

Nodes in i_fragtree are sorted according to ceph_compare_frag().
It means frag node in i_fragtree always follow its direct parent
node. To check if a leaf node is valid, we just need to check if
it's child of previous split node.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

-1 is CDIR_AUTH_PARENT, it means dir's auth mds is the same as
inode's auth mds
Signed-off-by: NYan, Zheng <zyan@redhat.com>

The algorithm that updates i_fragtree relies on that the frag tree
splits in mds reply are of the same order of i_fragtree. This is not
true because current MDS encodes frag tree splits in ascending order
of (unsigned)frag_t. But nodes in i_fragtree are sorted according to
ceph_frag_compare().

The fix is sort the frag tree splits first, then updates i_fragtree.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

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

If MDS sorts dentries in dirfrag in hash order, we use hash value to
compose dentry offset. dentry offset is:

  (0xff << 52) | ((24 bits hash) << 28) |
  (the nth entry hash hash collision)

This offset is stable across directory fragmentation. This alos means
there is no need to reset readdir offset if directory get fragmented
in the middle of readdir.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

Forward seek within same frag does not update fi->last_name, it will
not affect contents of later readdir reply. So there is no need to
forbid marking directory complete
Signed-off-by: NYan, Zheng <zyan@redhat.com>

This is preparation for using hash value as dentry 'offset'
Signed-off-by: NYan, Zheng <zyan@redhat.com>

Set a flag in readdir request, which indicates that client interprets
'end/complete' as bit flags. So that mds can reply additional flags in
readdir reply.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

This avoids defining multiple arrays for entries in readdir reply
Signed-off-by: NYan, Zheng <zyan@redhat.com>

don't distinguish leftmost frag from other frags. always use 2 as
first entry's offset.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

we never add snapdir and the hidden .ceph dir into readdir cache
Signed-off-by: NYan, Zheng <zyan@redhat.com>

use binary search to find cache index that corresponds to readdir
postion.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

Setxattr with NULL value and XATTR_REPLACE flag should be equivalent
to removexattr. But current MDS does not support deleting vxattrs through
MDS_OP_SETXATTR request. The workaround is sending MDS_OP_RMXATTR request
if setxattr actually removs xattr.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

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

symlink target is useless for debug and can be very long. It's annoying
to show it in debugfs/mdsc.
Signed-off-by: NYan, Zheng <zyan@redhat.com>

truncate_pagecache() may decrease inode's reference. This can cause
deadlock if inode's last reference is dropped and iput_final() wants
to evict the inode. (evict() calls inode_wait_for_writeback(), which
waits for ceph_writepages_start() to return).

The fix is use work thead to truncate dirty pages. Also add 'forced
umount' check to ceph_update_writeable_page(), which prevents new
pages getting dirty.
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>

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