This saves us a word of memory per file.
Reviewed-by: NYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

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>

Ceph does not need these, and they screw up our use of the dcache as a
consistent cache.
Signed-off-by: NSage Weil <sage@newdream.net>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Only a few file systems need this.  Start by pushing it down into each
rename method (except gfs2 and xfs) so that it can be dealt with on a
per-fs basis.
Acked-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSage Weil <sage@newdream.net>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Only a few file systems need this.  Start by pushing it down into each
fs rmdir method (except gfs2 and xfs) so it can be dealt with on a per-fs
basis.

This does not change behavior for any in-tree file systems.
Acked-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSage Weil <sage@newdream.net>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Both off and fi->offset are unsigned, so the difference is always >= 0.
Compare them directly instead of the sign of the difference.
Signed-off-by: NSage Weil <sage@newdream.net>

We allocate a buffer for rstats if the dirstat option is enabled.  Use
snprintf.
Signed-off-by: NSage Weil <sage@newdream.net>

Just for consistency's sake.  Fix obsolete comment too.
Signed-off-by: NSage Weil <sage@newdream.net>

The ino32 mount option forces the ceph fs to report 32 bit
ino values.  This is useful for 64 bit kernels with 32 bit userspace.
Signed-off-by: NYehuda Sadeh <yehuda@hq.newdream.net>

can't blindly check nd->flags in ->d_revalidate()
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Otherwise you can do things like

# mkdir .snap/foo
# cd .snap/foo/.snap
# ls
<badness>
Signed-off-by: NSage Weil <sage@newdream.net>

First, this was racy anyway: d_release isn't called until well after the
dentry is unhashed.  Second, this runs afoul of the recent dcache change
that clears d_parent prior to calling d_release (949854d0), causing a NULL
pointer dereference.
Signed-off-by: NSage Weil <sage@newdream.net>

Do not set the I_COMPLETE flag on directories until we resolve races with
dcache pruning.
Signed-off-by: NSage Weil <sage@newdream.net>

This reverts commit 97d79b40.

This fails to account for d_parent changes due to rename or disconnected
dentries due to submounts or NFS reexports.
Signed-off-by: NSage Weil <sage@newdream.net>

When creating a new dentry we now hold a reference to the parent
inode in the ceph_dentry.  This is required due to the new RCU
changes from 949854d0, which set dentry->d_parent to NULL in d_kill before
calling the ->release() callback.  If/when that behavior is changed, we can
revert this hack.
Signed-off-by: NYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

Add a ceph_dir_layout to the inode, and calculate dentry hash values based
on the parent directory's specified dir_hash function.  This is needed
because the old default Linux dcache hash function is extremely week and
leads to a poor distribution of files among dir fragments.
Signed-off-by: NSage Weil <sage@newdream.net>

Require filesystems be aware of .d_revalidate being called in rcu-walk
mode (nd->flags & LOOKUP_RCU). For now do a simple push down, returning
-ECHILD from all implementations.
Signed-off-by: NNick Piggin <npiggin@kernel.dk>

Reduce some branches and memory accesses in dcache lookup by adding dentry
flags to indicate common d_ops are set, rather than having to check them.
This saves a pointer memory access (dentry->d_op) in common path lookup
situations, and saves another pointer load and branch in cases where we
have d_op but not the particular operation.

Patched with:

git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i
Signed-off-by: NNick Piggin <npiggin@kernel.dk>

dcache_lock no longer protects anything. remove it.
Signed-off-by: NNick Piggin <npiggin@kernel.dk>

Protect d_subdirs and d_child with d_lock, except in filesystems that aren't
using dcache_lock for these anyway (eg. using i_mutex).

Note: if we change the locking rule in future so that ->d_child protection is
provided only with ->d_parent->d_lock, it may allow us to reduce some locking.
But it would be an exception to an otherwise regular locking scheme, so we'd
have to see some good results. Probably not worthwhile.
Signed-off-by: NNick Piggin <npiggin@kernel.dk>

Protect d_unhashed(dentry) condition with d_lock. This means keeping
DCACHE_UNHASHED bit in synch with hash manipulations.
Signed-off-by: NNick Piggin <npiggin@kernel.dk>

Make d_count non-atomic and protect it with d_lock. This allows us to ensure a
0 refcount dentry remains 0 without dcache_lock. It is also fairly natural when
we start protecting many other dentry members with d_lock.
Signed-off-by: NNick Piggin <npiggin@kernel.dk>

The fh_to_dentry etc. methods use ceph_init_dentry(), which assumes that
d_parent is defined.  It isn't for those callers, so check!
Signed-off-by: NSage Weil <sage@newdream.net>

last may be NULL, but we dereference it in the else branch without
checking.  Normally it doesn't trigger because last == NULL when fpos == 2,
but it could happen on a newly opened dir if the user seeks forward.
Reported-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NSage Weil <sage@newdream.net>

One of the readdir filldir_t callers was passing the raw ceph 64-bit ino
instead of the hashed 32-bit one, producing an EOVERFLOW in the filler
callback.  Fix this by calling the ceph_vino_to_ino() helper to do the
conversion.
Reported-by: NJan Smets <jan.smets@alcatel-lucent.com>
Tested-by: NJan Smets <jan.smets@alcatel-lucent.com>
Signed-off-by: NSage Weil <sage@newdream.net>

We start at offset 2 for the leftmost frag, and 0 for subsequent frags.
When we reach the end (rightmost), we go back to 2.  This fixes readdir on
fragmented (large) directories.
Signed-off-by: NSage Weil <sage@newdream.net>

Clear fi->last_name when it's freed.  The only caller is rewinddir() (or
equivalent lseek).
Signed-off-by: NSage Weil <sage@newdream.net>

We were taking dcache_lock inside of i_lock, which introduces a dependency
not found elsewhere in the kernel, complicationg the vfs locking
scalability work.  Since we don't actually need it here anyway, remove
it.

We only need i_lock to test for the I_COMPLETE flag, so be careful to do
so without dcache_lock held.
Signed-off-by: NSage Weil <sage@newdream.net>

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>