Commit Graph

201 Commits

Author SHA1 Message Date
Al Viro
77acfa29e1 [readdir] convert ceph
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-06-29 12:56:41 +04:00
Yan, Zheng
2f276c5111 ceph: use i_release_count to indicate dir's completeness
Current ceph code tracks directory's completeness in two places.
ceph_readdir() checks i_release_count to decide if it can set the
I_COMPLETE flag in i_ceph_flags. All other places check the I_COMPLETE
flag. This indirection introduces locking complexity.

This patch adds a new variable i_complete_count to ceph_inode_info.
Set i_release_count's value to it when marking a directory complete.
By comparing the two variables, we know if a directory is complete

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
2013-05-01 21:17:07 -07:00
Yan, Zheng
a8673d61ad ceph: use I_COMPLETE inode flag instead of D_COMPLETE flag
commit c6ffe10015 moved the flag that tracks if the dcache contents
for a directory are complete to dentry. The problem is there are
lots of places that use ceph_dir_{set,clear,test}_complete() while
holding i_ceph_lock. but ceph_dir_{set,clear,test}_complete() may
sleep because they call dput().

This patch basically reverts that commit. For ceph_d_prune(), it's
called with both the dentry to prune and the parent dentry are
locked. So it's safe to access the parent dentry's d_inode and
clear I_COMPLETE flag.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
2013-05-01 21:14:33 -07:00
Al Viro
496ad9aa8e new helper: file_inode(file)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-22 23:31:31 -05:00
Andrew Morton
965c8e59cf lseek: the "whence" argument is called "whence"
But the kernel decided to call it "origin" instead.  Fix most of the
sites.

Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-17 17:15:12 -08:00
Sage Weil
5ef50c3bec ceph: simplify+fix atomic_open
The initial ->atomic_open op was carried over from the old intent code,
which was incomplete and didn't really work.  Replace it with a fresh
method.  In particular:

 * always attempt to do an atomic open+lookup, both for the create case
   and for lookups of existing files.
 * fix symlink handling by returning 1 to the VFS so that we can follow
   the link to its destination. This fixes a longstanding ceph bug (#2392).

Signed-off-by: Sage Weil <sage@inktank.com>
2012-08-02 09:11:19 -07:00
Linus Torvalds
cc8362b1f6 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
Pull Ceph changes from Sage Weil:
 "Lots of stuff this time around:

   - lots of cleanup and refactoring in the libceph messenger code, and
     many hard to hit races and bugs closed as a result.
   - lots of cleanup and refactoring in the rbd code from Alex Elder,
     mostly in preparation for the layering functionality that will be
     coming in 3.7.
   - some misc rbd cleanups from Josh Durgin that are finally going
     upstream
   - support for CRUSH tunables (used by newer clusters to improve the
     data placement)
   - some cleanup in our use of d_parent that Al brought up a while back
   - a random collection of fixes across the tree

  There is another patch coming that fixes up our ->atomic_open()
  behavior, but I'm going to hammer on it a bit more before sending it."

Fix up conflicts due to commits that were already committed earlier in
drivers/block/rbd.c, net/ceph/{messenger.c, osd_client.c}

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (132 commits)
  rbd: create rbd_refresh_helper()
  rbd: return obj version in __rbd_refresh_header()
  rbd: fixes in rbd_header_from_disk()
  rbd: always pass ops array to rbd_req_sync_op()
  rbd: pass null version pointer in add_snap()
  rbd: make rbd_create_rw_ops() return a pointer
  rbd: have __rbd_add_snap_dev() return a pointer
  libceph: recheck con state after allocating incoming message
  libceph: change ceph_con_in_msg_alloc convention to be less weird
  libceph: avoid dropping con mutex before fault
  libceph: verify state after retaking con lock after dispatch
  libceph: revoke mon_client messages on session restart
  libceph: fix handling of immediate socket connect failure
  ceph: update MAINTAINERS file
  libceph: be less chatty about stray replies
  libceph: clear all flags on con_close
  libceph: clean up con flags
  libceph: replace connection state bits with states
  libceph: drop unnecessary CLOSED check in socket state change callback
  libceph: close socket directly from ceph_con_close()
  ...
2012-07-31 14:35:28 -07:00
Sage Weil
8842b3be96 ceph: clean up useless d_parent checks
d_parent is never NULL, and IS_ROOT() is the proper way to check for a
(non-self-referential) parent.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Sage Weil <sage@inktank.com>
2012-07-30 09:29:54 -07:00
Al Viro
ebfc3b49a7 don't pass nameidata to ->create()
boolean "does it have to be exclusive?" flag is passed instead;
Local filesystem should just ignore it - the object is guaranteed
not to be there yet.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:34:47 +04:00
Al Viro
00cd8dd3bf stop passing nameidata to ->lookup()
Just the flags; only NFS cares even about that, but there are
legitimate uses for such argument.  And getting rid of that
completely would require splitting ->lookup() into a couple
of methods (at least), so let's leave that alone for now...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:34:32 +04:00
Al Viro
0b728e1911 stop passing nameidata * to ->d_revalidate()
Just the lookup flags.  Die, bastard, die...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:34:14 +04:00
Al Viro
e45198a6ac make finish_no_open() return int
namely, 1 ;-)  That's what we want to return from ->atomic_open()
instances after finish_no_open().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:45 +04:00
Al Viro
30d9049474 kill struct opendata
Just pass struct file *.  Methods are happier that way...
There's no need to return struct file * from finish_open() now,
so let it return int.  Next: saner prototypes for parts in
namei.c

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:39 +04:00
Al Viro
d95852777b make ->atomic_open() return int
Change of calling conventions:
old		new
NULL		1
file		0
ERR_PTR(-ve)	-ve

Caller *knows* that struct file *; no need to return it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:35 +04:00
Al Viro
47237687d7 ->atomic_open() prototype change - pass int * instead of bool *
... and let finish_open() report having opened the file via that sucker.
Next step: don't modify od->filp at all.

[AV: FILE_CREATE was already used by cifs; Miklos' fix folded]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:31 +04:00
Miklos Szeredi
2d83bde9a1 ceph: implement i_op->atomic_open()
Add an ->atomic_open implementation which replaces the atomic lookup+open+create
operation implemented via ->lookup and ->create operations.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Sage Weil <sage@newdream.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:16 +04:00
Miklos Szeredi
3819219b59 ceph: remove unused arg from ceph_lookup_open()
What was the purpose of this?

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Sage Weil <sage@newdream.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:16 +04:00
Linus Torvalds
6c073a7ee2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  rbd: fix safety of rbd_put_client()
  rbd: fix a memory leak in rbd_get_client()
  ceph: create a new session lock to avoid lock inversion
  ceph: fix length validation in parse_reply_info()
  ceph: initialize client debugfs outside of monc->mutex
  ceph: change "ceph.layout" xattr to be "ceph.file.layout"
2012-02-02 15:47:33 -08:00
Alex Elder
d8fb02abdc ceph: create a new session lock to avoid lock inversion
Lockdep was reporting a possible circular lock dependency in
dentry_lease_is_valid().  That function needs to sample the
session's s_cap_gen and and s_cap_ttl fields coherently, but needs
to do so while holding a dentry lock.  The s_cap_lock field was
being used to protect the two fields, but that can't be taken while
holding a lock on a dentry within the session.

In most cases, the s_cap_gen and s_cap_ttl fields only get operated
on separately.  But in three cases they need to be updated together.
Implement a new lock to protect the spots updating both fields
atomically is required.

Signed-off-by: Alex Elder <elder@dreamhost.com>
Reviewed-by: Sage Weil <sage@newdream.net>
2012-02-02 12:49:19 -08:00
Linus Torvalds
1a52bb0b68 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  ceph: ensure prealloc_blob is in place when removing xattr
  rbd: initialize snap_rwsem in rbd_add()
  ceph: enable/disable dentry complete flags via mount option
  vfs: export symbol d_find_any_alias()
  ceph: always initialize the dentry in open_root_dentry()
  libceph: remove useless return value for osd_client __send_request()
  ceph: avoid iput() while holding spinlock in ceph_dir_fsync
  ceph: avoid useless dget/dput in encode_fh
  ceph: dereference pointer after checking for NULL
  crush: fix force for non-root TAKE
  ceph: remove unnecessary d_fsdata conditional checks
  ceph: Use kmemdup rather than duplicating its implementation

Fix up conflicts in fs/ceph/super.c (d_alloc_root() failure handling vs
always initialize the dentry in open_root_dentry)
2012-01-13 10:29:21 -08:00
Sage Weil
a40dc6cc2e ceph: enable/disable dentry complete flags via mount option
Enable/disable use of the dentry dir 'complete' flag via a mount option.
This lets the admin control whether ceph uses the dcache to satisfy
negative lookups or readdir when it has the entire directory contents in
its cache.

This is purely a performance optimization; correctness is guaranteed
whether it is enabled or not.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sage Weil <sage@newdream.net>
2012-01-12 11:00:40 -08:00
Sage Weil
2ff179e650 ceph: avoid iput() while holding spinlock in ceph_dir_fsync
ceph_mdsc_put_request() can call iput(), which can sleep.  Don't do that.

Fixes: #1812
Signed-off-by: Sage Weil <sage@newdream.net>
2012-01-10 08:57:02 -08:00
Sage Weil
3d8eb7a94e ceph: remove unnecessary d_fsdata conditional checks
We now set d_fsdata unconditionally on all dentries prior to setting up
the d_ops, so all of these checks are unnecessary.

Signed-off-by: Sage Weil <sage@newdream.net>
2012-01-10 08:56:56 -08:00
Al Viro
dba19c6064 get rid of open-coded S_ISREG(), etc.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:55:12 -05:00
Al Viro
1a67aafb5f switch ->mknod() to umode_t
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:54:54 -05:00
Al Viro
4acdaf27eb switch ->create() to umode_t
vfs_create() ignores everything outside of 16bit subset of its
mode argument; switching it to umode_t is obviously equivalent
and it's the only caller of the method

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:54:53 -05:00
Al Viro
18bb1db3e7 switch vfs_mkdir() and ->mkdir() to umode_t
vfs_mkdir() gets int, but immediately drops everything that might not
fit into umode_t and that's the only caller of ->mkdir()...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:54:53 -05:00
Sage Weil
a4d46363ce ceph: disable use of dcache for readdir etc.
Ceph attempts to use the dcache to satisfy negative lookups and readdir
when the entire directory contents are in cache.  Disable this behavior
until lingering bugs in this code are shaken out; we'll re-enable these
hooks once things are fully stable.

Signed-off-by: Sage Weil <sage@newdream.net>
2011-12-29 08:05:14 -08:00
Sage Weil
be655596b3 ceph: use i_ceph_lock instead of i_lock
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>
2011-12-07 10:46:44 -08:00
Sage Weil
774ac21da7 ceph: initialize root dentry
Set up d_fsdata on the root dentry.  This fixes a NULL pointer dereference
in ceph_d_prune on umount.  It also means we can eventually strip out all
of the conditional checks on d_fsdata because it is now set unconditionally
(prior to setting up the d_ops).

Fix the ceph_d_prune debug print while we're here.

Signed-off-by: Sage Weil <sage@newdream.net>
2011-11-11 09:50:17 -08:00
Sage Weil
c6ffe10015 ceph: use new D_COMPLETE dentry flag
We used to use a flag on the directory inode to track whether the dcache
contents for a directory were a complete cached copy.  Switch to a dentry
flag CEPH_D_COMPLETE that is safely updated by ->d_prune().

Signed-off-by: Sage Weil <sage@newdream.net>
2011-11-05 21:10:10 -07:00
Sage Weil
b58dc4100b ceph: clear parent D_COMPLETE flag when on dentry prune
When the VFS prunes a dentry from the cache, clear the D_COMPLETE flag
on the parent dentry.  Do this for the live and snapshotted namespaces. Do
not bother for the .snap dir contents, since we do not cache that.

Signed-off-by: Sage Weil <sage@newdream.net>
2011-11-03 09:23:49 -07:00
Linus Torvalds
ba5b56cb3e Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
* '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
  ...
2011-07-26 13:38:50 -07:00
Sage Weil
d79698da32 ceph: document unlocked d_parent accesses
For the most part we don't care about racing with rename when directing
MDS requests; either the old or new parent is fine.  Document that, and
do some minor cleanup.

Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
2011-07-26 11:31:26 -07:00
Sage Weil
41b02e1f9b ceph: explicitly reference rename old_dentry parent dir in request
We carry a pin on the parent directory for the rename source and dest
dentries.  For the source it's r_locked_dir; we need to explicitly
reference the old_dentry parent as well, since the dentry's d_parent may
change between when the request was created and pinned and when it is
freed.

Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
2011-07-26 11:31:14 -07:00
Sage Weil
e5f86dc377 ceph: avoid d_parent in ceph_dentry_hash; fix ceph_encode_fh() hashing bug
Have caller pass in a safely-obtained reference to the parent directory
for calculating a dentry's hash valud.

While we're here, simpify the flow through ceph_encode_fh() so that there
is a single exit point and cleanup.

Also fix a bug with the dentry hash calculation: calculate the hash for the
dentry we were given, not its parent.

Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
2011-07-26 11:30:55 -07:00
Sage Weil
bf1c6aca96 ceph: protect d_parent access in ceph_d_revalidate
Protect d_parent with d_lock.  Carry a reference.  Simplify the flow so
that there is a single exit point and cleanup.

Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
2011-07-26 11:30:43 -07:00
Sage Weil
5f21c96dd5 ceph: protect access to d_parent
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>
2011-07-26 11:30:29 -07:00
Sage Weil
48d0cbd124 ceph: handle racing calls to ceph_init_dentry
The ->lookup() and prepopulate_readdir() callers are working with unhashed
dentries, so we don't have to worry.  The export.c callers, though, need
to initialize something they got back from d_obtain_alias() and are
potentially racing with other callers.  Make sure we don't return unless
the dentry is properly initialized (by us or someone else).

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>
2011-07-26 11:30:15 -07:00
Sage Weil
468640e32c ceph: fix ceph_lookup_open intent usage
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>
2011-07-26 11:28:11 -07:00
Sage Weil
9cfa1098dc ceph: use flag bit for at_end readdir flag
This saves us a word of memory per file.

Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
2011-07-26 11:26:18 -07:00
Josef Bacik
02c24a8218 fs: push i_mutex and filemap_write_and_wait down into ->fsync() handlers
Btrfs needs to be able to control how filemap_write_and_wait_range() is called
in fsync to make it less of a painful operation, so push down taking i_mutex and
the calling of filemap_write_and_wait() down into the ->fsync() handlers.  Some
file systems can drop taking the i_mutex altogether it seems, like ext3 and
ocfs2.  For correctness sake I just pushed everything down in all cases to make
sure that we keep the current behavior the same for everybody, and then each
individual fs maintainer can make up their mind about what to do from there.
Thanks,

Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20 20:47:59 -04:00
Josef Bacik
06222e491e fs: handle SEEK_HOLE/SEEK_DATA properly in all fs's that define their own llseek
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>
2011-07-20 20:47:58 -04:00
Al Viro
b85fd6bdc9 don't open-code parent_ino() in assorted ->readdir()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20 20:47:54 -04:00
Al Viro
a127e0af59 ceph: LOOKUP_OPEN is set only when it's the last component
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20 01:43:59 -04:00
Sage Weil
70b666c3b4 ceph: use ihold when we already have an inode ref
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: Sage Weil <sage@newdream.net>
2011-06-07 21:34:11 -07:00
Sage Weil
da39822c65 ceph: fix broken comparison in readdir loop
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: Sage Weil <sage@newdream.net>
2011-05-19 11:25:04 -07:00
Sage Weil
ae59808301 ceph: use snprintf for dirstat content
We allocate a buffer for rstats if the dirstat option is enabled.  Use
snprintf.

Signed-off-by: Sage Weil <sage@newdream.net>
2011-05-19 11:25:02 -07:00
Sage Weil
147851d2dc ceph: rename dentry_release -> d_release, fix comment
Just for consistency's sake.  Fix obsolete comment too.

Signed-off-by: Sage Weil <sage@newdream.net>
2011-03-21 12:24:26 -07:00
Yehuda Sadeh
ad1fee96cb ceph: add ino32 mount option
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: Yehuda Sadeh <yehuda@hq.newdream.net>
2011-03-21 12:24:22 -07:00
Al Viro
0eb980e317 ceph: fix d_revalidate oopsen on NFS exports
can't blindly check nd->flags in ->d_revalidate()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-10 03:44:05 -05:00
Sage Weil
455cec0abf ceph: no .snap inside of snapped namespace
Otherwise you can do things like

# mkdir .snap/foo
# cd .snap/foo/.snap
# ls
<badness>

Signed-off-by: Sage Weil <sage@newdream.net>
2011-03-04 12:25:09 -08:00
Sage Weil
16a8b70a5a ceph: do not clear I_COMPLETE from d_release
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: Sage Weil <sage@newdream.net>
2011-03-03 10:09:52 -08:00
Sage Weil
b545cc1505 ceph: do not set I_COMPLETE
Do not set the I_COMPLETE flag on directories until we resolve races with
dcache pruning.

Signed-off-by: Sage Weil <sage@newdream.net>
2011-03-03 10:09:51 -08:00
Sage Weil
9bde178d05 Revert "ceph: keep reference to parent inode on ceph_dentry"
This reverts commit 97d79b403e.

This fails to account for d_parent changes due to rename or disconnected
dentries due to submounts or NFS reexports.

Signed-off-by: Sage Weil <sage@newdream.net>
2011-03-03 10:09:50 -08:00
Linus Torvalds
8bd89ca220 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  ceph: keep reference to parent inode on ceph_dentry
  ceph: queue cap_snaps once per realm
  libceph: fix socket write error handling
  libceph: fix socket read error handling
2011-02-21 15:01:38 -08:00
Yehuda Sadeh
97d79b403e ceph: keep reference to parent inode on ceph_dentry
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: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
2011-02-19 19:59:14 -08:00
Linus Torvalds
a170315420 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  rbd: fix cleanup when trying to mount inexistent image
  net/ceph: make ceph_msgr_wq non-reentrant
  ceph: fsc->*_wq's aren't used in memory reclaim path
  ceph: Always free allocated memory in osdmap_decode()
  ceph: Makefile: Remove unnessary code
  ceph: associate requests with opening sessions
  ceph: drop redundant r_mds field
  ceph: implement DIRLAYOUTHASH feature to get dir layout from MDS
  ceph: add dir_layout to inode
2011-01-13 10:25:24 -08:00
Sage Weil
6c0f3af72c ceph: add dir_layout to inode
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: Sage Weil <sage@newdream.net>
2011-01-12 15:15:12 -08:00
Nick Piggin
34286d6662 fs: rcu-walk aware d_revalidate method
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: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:29 +11:00
Nick Piggin
fb045adb99 fs: dcache reduce branches in lookup path
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: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:28 +11:00
Nick Piggin
b5c84bf6f6 fs: dcache remove dcache_lock
dcache_lock no longer protects anything. remove it.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:23 +11:00
Nick Piggin
2fd6b7f507 fs: dcache scale subdirs
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: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:21 +11:00
Nick Piggin
da5029563a fs: dcache scale d_unhashed
Protect d_unhashed(dentry) condition with d_lock. This means keeping
DCACHE_UNHASHED bit in synch with hash manipulations.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:21 +11:00
Nick Piggin
b7ab39f631 fs: dcache scale dentry refcount
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: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:21 +11:00
Sage Weil
92cf765237 ceph: fix null pointer dereference in ceph_init_dentry for nfs reexport
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: Sage Weil <sage@newdream.net>
2010-12-17 09:53:48 -08:00
Sage Weil
884ea89276 ceph: avoid possible null deref in readdir after dir llseek
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: Dan Carpenter <error27@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>
2010-12-01 14:15:31 -08:00
Sage Weil
3105c19c45 ceph: fix readdir EOVERFLOW on 32-bit archs
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: Jan Smets <jan.smets@alcatel-lucent.com>
Tested-by: Jan Smets <jan.smets@alcatel-lucent.com>
Signed-off-by: Sage Weil <sage@newdream.net>
2010-11-18 09:15:07 -08:00
Sage Weil
7b88dadc13 ceph: fix frag offset for non-leftmost frags
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: Sage Weil <sage@newdream.net>
2010-11-11 16:48:59 -08:00
Sage Weil
a1629c3b24 ceph: fix dangling pointer
Clear fi->last_name when it's freed.  The only caller is rewinddir() (or
equivalent lseek).

Signed-off-by: Sage Weil <sage@newdream.net>
2010-11-11 15:24:06 -08:00
Sage Weil
efa4c1206e ceph: do not carry i_lock for readdir from dcache
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: Sage Weil <sage@newdream.net>
2010-10-20 15:38:27 -07:00
Sage Weil
4c32f5dda5 ceph: do not hide .snap in root directory
Snaps in the root directory are now supported by the MDS, and harmless on
older versions.

Signed-off-by: Sage Weil <sage@newdream.net>
2010-10-20 15:38:14 -07:00
Yehuda Sadeh
3d14c5d2b6 ceph: factor out libceph from Ceph file system
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: Sage Weil <sage@newdream.net>
2010-10-20 15:37:28 -07:00
Sage Weil
ca04d9c3ec ceph: fix null pointer deref on anon root dentry release
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: Sage Weil <sage@newdream.net>
2010-09-11 10:52:47 -07:00
Sage Weil
36e21687e6 ceph: initialize fields on new dentry_infos
Signed-off-by: Sage Weil <sage@newdream.net>
2010-08-24 16:24:19 -07:00
Sage Weil
52dfb8ac0e ceph: constify dentry_operations
This makes checkpatch happy.

Signed-off-by: Sage Weil <sage@newdream.net>
2010-08-03 10:25:30 -07:00
Yehuda Sadeh
cd84db6e40 ceph: code cleanup
Mainly fixing minor issues reported by sparse.

Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
2010-08-01 20:11:40 -07:00
Sage Weil
252af52146 ceph: fix d_release dop for snapdir, snapped dentries
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: Sage Weil <sage@newdream.net>
2010-07-23 10:02:05 -07:00
Sage Weil
a0dff78dab ceph: avoid dcache readdir for snapdir
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: Sage Weil <sage@newdream.net>
2010-07-22 13:50:45 -07:00
Linus Torvalds
b612a05537 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  ceph: clean up on forwarded aborted mds request
  ceph: fix leak of osd authorizer
  ceph: close out mds, osd connections before stopping auth
  ceph: make lease code DN specific
  fs/ceph: Use ERR_CAST
  ceph: renew auth tickets before they expire
  ceph: do not resend mon requests on auth ticket renewal
  ceph: removed duplicated #includes
  ceph: avoid possible null dereference
  ceph: make mds requests killable, not interruptible
  sched: add wait_for_completion_killable_timeout
2010-05-30 08:56:39 -07:00
Julia Lawall
7e34bc524e fs/ceph: Use ERR_CAST
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: Julia Lawall <julia@diku.dk>
Signed-off-by: Sage Weil <sage@newdream.net>
2010-05-29 09:12:41 -07:00
Christoph Hellwig
7ea8085910 drop unused dentry argument to ->fsync
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-27 22:05:02 -04:00
Sage Weil
23804d91f1 ceph: specify max_bytes on readdir replies
Specify max bytes in request to bound size of reply.  Add associated
mount option with default value of 512 KB.

Signed-off-by: Sage Weil <sage@newdream.net>
2010-05-17 15:25:41 -07:00
Sage Weil
1cd3935bed ceph: set dn offset when spliced
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: Sage Weil <sage@newdream.net>
2010-05-17 15:25:28 -07:00
Sage Weil
f1f2765fae ceph: set next_offset on readdir finish
Set next_offset to 2 (always 2!), not 0, on readdir finish.

Signed-off-by: Sage Weil <sage@newdream.net>
2010-05-17 15:25:26 -07:00
Sage Weil
8c6efb58a5 ceph: fix memory leak due to possible dentry init race
Free dentry_info in error path.

Signed-off-by: Sage Weil <sage@newdream.net>
2010-05-17 15:25:23 -07:00
Cheng Renquan
640ef79d27 ceph: use ceph_sb_to_client instead of ceph_client
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: Cheng Renquan <crquan@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>
2010-05-17 15:25:17 -07:00
Sage Weil
81a6cf2d30 ceph: invalidate affected dentry leases on aborted requests
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: Sage Weil <sage@newdream.net>
2010-05-17 10:25:45 -07:00
Sage Weil
ea1409f961 ceph: clear dir complete, invalidate dentry on replayed rename
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: Sage Weil <sage@newdream.net>
2010-05-03 10:49:25 -07:00
Linus Torvalds
96e35b40c0 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  ceph: use separate class for ceph sockets' sk_lock
  ceph: reserve one more caps space when doing readdir
  ceph: queue_cap_snap should always queue dirty context
  ceph: fix dentry reference leak in dcache readdir
  ceph: decode v5 of osdmap (pool names) [protocol change]
  ceph: fix ack counter reset on connection reset
  ceph: fix leaked inode ref due to snap metadata writeback race
  ceph: fix snap context reference leaks
  ceph: allow writeback of snapped pages older than 'oldest' snapc
  ceph: fix dentry rehashing on virtual .snap dir
2010-04-14 18:45:31 -07:00
Yehuda Sadeh
e1e4dd0caa ceph: reserve one more caps space when doing readdir
We were missing space for the directory cap.  The result was a BUG at
fs/ceph/caps.c:2178.

Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
2010-04-13 12:28:54 -07:00
Sage Weil
f5b066287c ceph: fix dentry reference leak in dcache readdir
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: Sage Weil <sage@newdream.net>
2010-04-12 14:25:51 -07:00
Sage Weil
9358c6d4c0 ceph: fix dentry rehashing on virtual .snap dir
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: Sage Weil <sage@newdream.net>
2010-03-30 13:55:22 -07:00
Tejun Heo
5a0e3ad6af 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: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Sage Weil
393f662096 ceph: fix possible double-free of mds request reference
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: Sage Weil <sage@newdream.net>
2010-03-23 07:47:06 -07:00
Sage Weil
04a419f908 ceph: add feature bits to connection handshake (protocol change)
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: Sage Weil <sage@newdream.net>
2009-12-23 09:30:21 -08:00
Sage Weil
5de7bf8afa ceph: do not drop lease during revalidate
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: Sage Weil <sage@newdream.net>
2009-12-21 16:39:58 -08:00
Sage Weil
1d1de9160e ceph: hide /.ceph from readdir results
We need to skip /.ceph in (cached) readdir results, and exclude "/.ceph"
from the cached ENOENT lookup check.

Signed-off-by: Sage Weil <sage@newdream.net>
2009-12-03 14:59:48 -08:00
Sage Weil
09b8a7d2af ceph: exclude snapdir from readdir results
It was hidden from sync readdir, but not the cached dcache version.

Signed-off-by: Sage Weil <sage@newdream.net>
2009-11-11 15:50:25 -08:00
Sage Weil
6b8051855d ceph: allocate and parse mount args before client instance
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: Sage Weil <sage@newdream.net>
2009-10-27 11:57:03 -07:00
Sage Weil
2817b000b0 ceph: directory operations
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: Sage Weil <sage@newdream.net>
2009-10-06 11:31:08 -07:00