Commit 06222e491e663dac939f04b125c9dc52126a75c4 got the if wrong so that
it always evaluates as true.  This is semantically harmless, but makes
SEEK_CUR and SEEK_SET needlessly query the server.

Rewrite the if to explicitly enumerate the cases we DO need a valid i_size
to make this code less fragile.

Reported-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>

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: Amon Ott <a.ott@m-privacy.de>
Signed-off-by: Sage Weil <sage@newdream.net>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (23 commits)
  ceph: document unlocked d_parent accesses
  ceph: explicitly reference rename old_dentry parent dir in request
  ceph: document locking for ceph_set_dentry_offset
  ceph: avoid d_parent in ceph_dentry_hash; fix ceph_encode_fh() hashing bug
  ceph: protect d_parent access in ceph_d_revalidate
  ceph: protect access to d_parent
  ceph: handle racing calls to ceph_init_dentry
  ceph: set dir complete frag after adding capability
  rbd: set blk_queue request sizes to object size
  ceph: set up readahead size when rsize is not passed
  rbd: cancel watch request when releasing the device
  ceph: ignore lease mask
  ceph: fix ceph_lookup_open intent usage
  ceph: only link open operations to directory unsafe list if O_CREAT|O_TRUNC
  ceph: fix bad parent_inode calc in ceph_lookup_open
  ceph: avoid carrying Fw cap during write into page cache
  libceph: don't time out osd requests that haven't been received
  ceph: report f_bfree based on kb_avail rather than diffing.
  ceph: only queue capsnap if caps are dirty
  ceph: fix snap writeback when racing with writes
  ...

d_parent is protected by d_lock: use it when looking up a dentry's parent
directory inode.  Also take a reference and drop it in the caller to avoid
a use-after-free.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>

We weren't properly calling lookup_instantiate_filp when setting up the
lookup intent, which could lead to file leakage on errors.  So:

 - use separate helper for the hidden snapdir translation, immediately
   following the mds request
 - use ceph_finish_lookup for the final dentry/return value dance in the
   exit path
 - lookup_instantiate_filp on success

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>

We only need to put these on the directory unsafe list if they have
side effects that fsync(2) should flush out.

Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>

We were always getting NULL here because the intent file f_dentry is always
NULL at this point, which means we were always passing NULL to
ceph_mdsc_do_request.  In reality, this was fine, since this isn't
currently ever a write operation that needs to get strung on the dir's
unsafe list.

Use the dir explicitly, and only pass it if this open has side-effects that
a dir fsync should flush.

Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>

The generic_file_aio_write call may block on balance_dirty_pages while we
flush data to the OSDs.  If we hold a reference to the FILE_WR cap during
that interval revocation by the MDS (e.g., to do a stat(2)) may be very
slow.

Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>

This allows us to force IO through the sync path which you normally only
get when multiple clients are reading/writing to the same file or by
mounting with -o sync.  Among other things, this lets test programs verify
correctness with a single mount.

Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>

This converts everybody to handle SEEK_HOLE/SEEK_DATA properly.  In some cases
we just return -EINVAL, in others we do the normal generic thing, and in others
we're simply making sure that the properly due-dilligence is done.  For example
in NFS/CIFS we need to make sure the file size is update properly for the
SEEK_HOLE and SEEK_DATA case, but since it calls the generic llseek stuff itself
that is all we have to do.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>