ceph: let MDS adjust readdir 'frag'

If readdir 'frag' is adjusted, readdir 'offset' should be reset.
Otherwise some dentries may be lost when readdir and fragmenting
directory happen at the some.

Another way to fix this issue is let MDS adjust readdir 'frag'.
The code that handles MDS reply reset the readdir 'offset' if
the readdir reply is different than the requested one.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: simplify ceph_fh_to_dentry()

MDS handles LOOKUPHASH and LOOKUPINO MDS requests in the same way.
So __cfh_to_dentry() is redundant.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: fix ceph_fh_to_parent()

ceph_fh_to_parent() finds the inode that corresponds to the 'ino' field
of struct ceph_nfs_confh. This is wrong, it should find the inode that
corresponds to the 'parent_ino' field.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: add get_parent() callback for export_operations

The callback uses LOOKUPPARENT MDS request to find parent.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: print inode number for LOOKUPINO/LOOKUPPARENT request

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: avoid useless ceph_get_dentry_parent_inode() in ceph_rename()

This is just old_dir; no reason to abuse the dcache pointers.

Reported-by: Al Viro <viro.zeniv.linux.org.uk>
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: do not chain inode updates to parent fsync

The fsync(dirfd) only covers namespace operations, not inode updates.
We do not need to cover setattr variants or O_TRUNC.

Reported-by: Al Viro <viro@xeniv.linux.org.uk>
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: do not assume r_old_dentry[_dir] always set together

Do not assume that r_old_dentry implies that r_old_dentry_dir is also
true.  Separate out the ref cleanup and make the debugs dump behave when
it is NULL.

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: do not set r_old_dentry_dir on link()

This is racy--we do not know whather d_parent has changed out from
underneath us because i_mutex is not held on the source inode's directory.

Also, taking this reference is useless.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>