Snaps in the root directory are now supported by the MDS, and harmless on
older versions.
Signed-off-by: NSage Weil <sage@newdream.net>

This factors out protocol and low-level storage parts of ceph into a
separate libceph module living in net/ceph and include/linux/ceph.  This
is mostly a matter of moving files around.  However, a few key pieces
of the interface change as well:

 - ceph_client becomes ceph_fs_client and ceph_client, where the latter
   captures the mon and osd clients, and the fs_client gets the mds client
   and file system specific pieces.
 - Mount option parsing and debugfs setup is correspondingly broken into
   two pieces.
 - The mon client gets a generic handler callback for otherwise unknown
   messages (mds map, in this case).
 - The basic supported/required feature bits can be expanded (and are by
   ceph_fs_client).

No functional change, aside from some subtle error handling cases that got
cleaned up in the refactoring process.
Signed-off-by: NSage Weil <sage@newdream.net>

When we release a root dentry, particularly after a splice, the parent
(actually our) inode was evaluating to NULL and was getting dereferenced
by ceph_snap().  This is reproduced by something as simple as

 mount -t ceph monhost:/a/b mnt
 mount -t ceph monhost:/a mnt2
 ls mnt2

A splice_dentry() would kill the old 'b' inode's root dentry, and we'd
crash while releasing it.

Fix by checking for both the ROOT and NULL cases explicitly.  We only need
to invalidate the parent dir when we have a correct parent to invalidate.
Signed-off-by: NSage Weil <sage@newdream.net>

Signed-off-by: NSage Weil <sage@newdream.net>

This makes checkpatch happy.
Signed-off-by: NSage Weil <sage@newdream.net>

Mainly fixing minor issues reported by sparse.
Signed-off-by: NYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

We need to set the d_release dop for snapdir and snapped dentries so that
the ceph_dentry_info struct gets released.  We also use the dcache to
cache readdir results when possible, which only works if we know when
dentries are dropped from the cache.  Since we don't use the dcache for
readdir in the hidden snapdir, avoid that case in ceph_dentry_release.
Signed-off-by: NSage Weil <sage@newdream.net>

We should always go to the MDS for readdir on the hidden snapdir.  The
set of snapshots can change at any time; the client can't trust its cache
for that.
Signed-off-by: NSage Weil <sage@newdream.net>

Use ERR_CAST(x) rather than ERR_PTR(PTR_ERR(x)).  The former makes more
clear what is the purpose of the operation, which otherwise looks like a
no-op.

In the case of fs/ceph/inode.c, ERR_CAST is not needed, because the type of
the returned value is the same as the type of the enclosing function.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
type T;
T x;
identifier f;
@@

T f (...) { <+...
- ERR_PTR(PTR_ERR(x))
+ x
 ...+> }

@@
expression x;
@@

- ERR_PTR(PTR_ERR(x))
+ ERR_CAST(x)
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NSage Weil <sage@newdream.net>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Specify max bytes in request to bound size of reply.  Add associated
mount option with default value of 512 KB.
Signed-off-by: NSage Weil <sage@newdream.net>

We want to assign an offset when the dentry goes from null to linked, which
is always done by splice_dentry().  Notably, we should NOT assign an
offset when a dentry is first created and is still null.

BUG if we try to splice a non-null dentry (we shouldn't).
Signed-off-by: NSage Weil <sage@newdream.net>

Set next_offset to 2 (always 2!), not 0, on readdir finish.
Signed-off-by: NSage Weil <sage@newdream.net>

Free dentry_info in error path.
Signed-off-by: NSage Weil <sage@newdream.net>

ceph_sb_to_client and ceph_client are really identical, we need to dump
one; while function ceph_client is confusing with "struct ceph_client",
ceph_sb_to_client's definition is more clear; so we'd better switch all
call to ceph_sb_to_client.

  -static inline struct ceph_client *ceph_client(struct super_block *sb)
  -{
  -	return sb->s_fs_info;
  -}
Signed-off-by: NCheng Renquan <crquan@gmail.com>
Signed-off-by: NSage Weil <sage@newdream.net>

If we abort a request, we return to caller, but the request may still
complete.  And if we hold the dir FILE_EXCL bit, we may not release a
lease when sending a request.  A simple un-tar, control-c, un-tar again
will reproduce the bug (manifested as a 'Cannot open: File exists').

Ensure we invalidate affected dentry leases (as well dir I_COMPLETE) so
we don't have valid (but incorrect) leases.  Do the same, consistently, at
other sites where I_COMPLETE is similarly cleared.
Signed-off-by: NSage Weil <sage@newdream.net>

If a rename operation is resent to the MDS following an MDS restart, the
client does not get a full reply (containing the resulting metadata) back.
In that case, a ceph_rename() needs to compensate by doing anything useful
that fill_inode() would have, like d_move().

It also needs to invalidate the dentry (to workaround the vfs_rename_dir()
bug) and clear the dir complete flag, just like fill_trace().
Signed-off-by: NSage Weil <sage@newdream.net>

We were missing space for the directory cap.  The result was a BUG at
fs/ceph/caps.c:2178.
Signed-off-by: NYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

When filldir returned an error (e.g. buffer full for a large directory),
we would leak a dentry reference, causing an oops on umount.
Signed-off-by: NSage Weil <sage@newdream.net>

If a lookup fails on the magic .snap directory, we bind it to a magic
snap directory inode in ceph_lookup_finish().  That code assumes the dentry
is unhashed, but a recent server-side change started returning NULL leases
on lookup failure, causing the .snap dentry to be hashed and NULL by
ceph_fill_trace().

This causes dentry hash chain corruption, or a dies when d_rehash()
includes
	BUG_ON(!d_unhashed(entry));

So, avoid processing the NULL dentry lease if it the dentry matches the
snapdir name in ceph_fill_trace().  That allows the lookup completion to
properly bind it to the snapdir inode.  BUG there if dentry is hashed to
be sure.
Signed-off-by: NSage Weil <sage@newdream.net>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

Clear pointer to mds request after dropping the reference to
ensure we don't drop it again, as there is at least one error
path through this function that does not reset fi->last_readdir
to a new value.
Signed-off-by: NSage Weil <sage@newdream.net>

Define supported and required feature set.  Fail connection if the server
requires features we do not support (TAG_FEATURES), or if the server does
not support features we require.
Signed-off-by: NSage Weil <sage@newdream.net>

We need to hold session s_mutex for __ceph_mdsc_drop_dentry_lease(), which
we don't, so skip it.  It was purely an optimization.
Signed-off-by: NSage Weil <sage@newdream.net>

We need to skip /.ceph in (cached) readdir results, and exclude "/.ceph"
from the cached ENOENT lookup check.
Signed-off-by: NSage Weil <sage@newdream.net>

It was hidden from sync readdir, but not the cached dcache version.
Signed-off-by: NSage Weil <sage@newdream.net>

This simplifies much of the error handling during mount.  It also means
that we have the mount args before client creation, and we can initialize
based on those options.
Signed-off-by: NSage Weil <sage@newdream.net>

Directory operations, including lookup, are defined here.  We take
advantage of lookup intents when possible.  For the most part, we just
need to build the proper requests for the metadata server(s) and
pass things off to the mds_client.

The results of most operations are normally incorporated into the
client's cache when the reply is parsed by ceph_fill_trace().
However, if the MDS replies without a trace (e.g., when retrying an
update after an MDS failure recovery), some operation-specific cleanup
may be needed.

We can validate cached dentries in two ways.  A per-dentry lease may
be issued by the MDS, or a per-directory cap may be issued that acts
as a lease on the entire directory.  In the latter case, a 'gen' value
is used to determine which dentries belong to the currently leased
directory contents.

We normally prepopulate the dcache and icache with readdir results.
This makes subsequent lookups and getattrs avoid any server
interaction.  It also lets us satisfy readdir operation by peeking at
the dcache IFF we hold the per-directory cap/lease, previously
performed a readdir, and haven't dropped any of the resulting
dentries.
Signed-off-by: NSage Weil <sage@newdream.net>