[patch 12/52] fs: dcache scale dentry refcount

From: npiggin
Date: Wed Jun 23 2010 - 23:21:35 EST

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@xxxxxxx>
---
arch/powerpc/platforms/cell/spufs/inode.c | 2
drivers/infiniband/hw/ipath/ipath_fs.c | 2
fs/autofs4/expire.c | 8 +-
fs/autofs4/root.c | 6 -
fs/coda/dir.c | 2
fs/configfs/dir.c | 3
fs/configfs/inode.c | 2
fs/dcache.c | 107 ++++++++++++++++++++++--------
fs/ecryptfs/inode.c | 2
fs/exportfs/expfs.c | 9 ++
fs/hpfs/namei.c | 2
fs/locks.c | 2
fs/namei.c | 2
fs/nfs/dir.c | 12 +--
fs/nfsd/vfs.c | 5 -
fs/notify/fsnotify.c | 11 ++-
fs/notify/inotify/inotify.c | 14 +++
fs/smbfs/dir.c | 8 +-
fs/smbfs/proc.c | 8 +-
include/linux/dcache.h | 29 ++++----
kernel/cgroup.c | 2
21 files changed, 162 insertions(+), 76 deletions(-)

Index: linux-2.6/fs/dcache.c
===================================================================
--- linux-2.6.orig/fs/dcache.c
+++ linux-2.6/fs/dcache.c
@@ -45,6 +45,7 @@
* - d_flags
* - d_name
* - d_lru
+ * - d_count
*
* Ordering:
* dcache_lock
@@ -112,6 +113,7 @@ static void d_callback(struct rcu_head *
static void d_free(struct dentry *dentry)
{
atomic_dec(&dentry_stat.nr_dentry);
+ BUG_ON(dentry->d_count);
if (dentry->d_op && dentry->d_op->d_release)
dentry->d_op->d_release(dentry);
/* if dentry was never inserted into hash, immediate free is OK */
@@ -263,13 +265,23 @@ void dput(struct dentry *dentry)
return;

repeat:
- if (atomic_read(&dentry->d_count) == 1)
+ if (dentry->d_count == 1)
might_sleep();
- if (!atomic_dec_and_lock(&dentry->d_count, &dcache_lock))
- return;
-
spin_lock(&dentry->d_lock);
- if (atomic_read(&dentry->d_count)) {
+ if (dentry->d_count == 1) {
+ if (!spin_trylock(&dcache_lock)) {
+ /*
+ * Something of a livelock possibility we could avoid
+ * by taking dcache_lock and trying again, but we
+ * want to reduce dcache_lock anyway so this will
+ * get improved.
+ */
+ spin_unlock(&dentry->d_lock);
+ goto repeat;
+ }
+ }
+ dentry->d_count--;
+ if (dentry->d_count) {
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
return;
@@ -347,7 +359,7 @@ int d_invalidate(struct dentry * dentry)
* working directory or similar).
*/
spin_lock(&dentry->d_lock);
- if (atomic_read(&dentry->d_count) > 1) {
+ if (dentry->d_count > 1) {
if (dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode)) {
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
@@ -362,29 +374,60 @@ int d_invalidate(struct dentry * dentry)
}
EXPORT_SYMBOL(d_invalidate);

-/* This should be called _only_ with dcache_lock held */
+/* This must be called with dcache_lock and d_lock held */
static inline struct dentry * __dget_locked_dlock(struct dentry *dentry)
{
- atomic_inc(&dentry->d_count);
+ dentry->d_count++;
dentry_lru_del_init(dentry);
return dentry;
}

+/* This should be called _only_ with dcache_lock held */
static inline struct dentry * __dget_locked(struct dentry *dentry)
{
- atomic_inc(&dentry->d_count);
spin_lock(&dentry->d_lock);
- dentry_lru_del_init(dentry);
+ __dget_locked_dlock(dentry);
spin_unlock(&dentry->d_lock);
return dentry;
}

+struct dentry * dget_locked_dlock(struct dentry *dentry)
+{
+ return __dget_locked_dlock(dentry);
+}
+
struct dentry * dget_locked(struct dentry *dentry)
{
return __dget_locked(dentry);
}
EXPORT_SYMBOL(dget_locked);

+struct dentry *dget_parent(struct dentry *dentry)
+{
+ struct dentry *ret;
+
+repeat:
+ spin_lock(&dentry->d_lock);
+ ret = dentry->d_parent;
+ if (!ret)
+ goto out;
+ if (dentry == ret) {
+ ret->d_count++;
+ goto out;
+ }
+ if (!spin_trylock(&ret->d_lock)) {
+ spin_unlock(&dentry->d_lock);
+ goto repeat;
+ }
+ BUG_ON(!ret->d_count);
+ ret->d_count++;
+ spin_unlock(&ret->d_lock);
+out:
+ spin_unlock(&dentry->d_lock);
+ return ret;
+}
+EXPORT_SYMBOL(dget_parent);
+
/**
* d_find_alias - grab a hashed alias of inode
* @inode: inode in question
@@ -453,7 +496,7 @@ restart:
spin_lock(&dcache_lock);
list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
spin_lock(&dentry->d_lock);
- if (!atomic_read(&dentry->d_count)) {
+ if (!dentry->d_count) {
__dget_locked_dlock(dentry);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
@@ -489,7 +532,10 @@ static void prune_one_dentry(struct dent
*/
while (dentry) {
spin_lock(&dcache_lock);
- if (!atomic_dec_and_lock(&dentry->d_count, &dentry->d_lock)) {
+ spin_lock(&dentry->d_lock);
+ dentry->d_count--;
+ if (dentry->d_count) {
+ spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
return;
}
@@ -575,7 +621,7 @@ again:
* the LRU because of laziness during lookup. Do not free
* it - just keep it off the LRU list.
*/
- if (atomic_read(&dentry->d_count)) {
+ if (dentry->d_count) {
spin_unlock(&dentry->d_lock);
continue;
}
@@ -736,7 +782,7 @@ static void shrink_dcache_for_umount_sub
do {
struct inode *inode;

- if (atomic_read(&dentry->d_count) != 0) {
+ if (dentry->d_count != 0) {
printk(KERN_ERR
"BUG: Dentry %p{i=%lx,n=%s}"
" still in use (%d)"
@@ -745,7 +791,7 @@ static void shrink_dcache_for_umount_sub
dentry->d_inode ?
dentry->d_inode->i_ino : 0UL,
dentry->d_name.name,
- atomic_read(&dentry->d_count),
+ dentry->d_count,
dentry->d_sb->s_type->name,
dentry->d_sb->s_id);
BUG();
@@ -755,7 +801,9 @@ static void shrink_dcache_for_umount_sub
parent = NULL;
else {
parent = dentry->d_parent;
- atomic_dec(&parent->d_count);
+ spin_lock(&parent->d_lock);
+ parent->d_count--;
+ spin_unlock(&parent->d_lock);
}

list_del(&dentry->d_u.d_child);
@@ -810,7 +858,9 @@ void shrink_dcache_for_umount(struct sup

dentry = sb->s_root;
sb->s_root = NULL;
- atomic_dec(&dentry->d_count);
+ spin_lock(&dentry->d_lock);
+ dentry->d_count--;
+ spin_unlock(&dentry->d_lock);
shrink_dcache_for_umount_subtree(dentry);

while (!hlist_empty(&sb->s_anon)) {
@@ -903,17 +953,15 @@ resume:

spin_lock(&dentry->d_lock);
dentry_lru_del_init(dentry);
- spin_unlock(&dentry->d_lock);
/*
* move only zero ref count dentries to the end
* of the unused list for prune_dcache
*/
- if (!atomic_read(&dentry->d_count)) {
- spin_lock(&dentry->d_lock);
+ if (!dentry->d_count) {
dentry_lru_add_tail(dentry);
- spin_unlock(&dentry->d_lock);
found++;
}
+ spin_unlock(&dentry->d_lock);

/*
* We can return to the caller if we have found some (this
@@ -1023,7 +1071,7 @@ struct dentry *d_alloc(struct dentry * p
memcpy(dname, name->name, name->len);
dname[name->len] = 0;

- atomic_set(&dentry->d_count, 1);
+ dentry->d_count = 1;
dentry->d_flags = DCACHE_UNHASHED;
spin_lock_init(&dentry->d_lock);
dentry->d_inode = NULL;
@@ -1497,7 +1545,7 @@ struct dentry * __d_lookup(struct dentry
goto next;
}

- atomic_inc(&dentry->d_count);
+ dentry->d_count++;
found = dentry;
spin_unlock(&dentry->d_lock);
break;
@@ -1558,6 +1606,7 @@ int d_validate(struct dentry *dentry, st
goto out;

spin_lock(&dcache_lock);
+ spin_lock(&dentry->d_lock);
spin_lock(&dcache_hash_lock);
base = d_hash(dparent, dentry->d_name.hash);
hlist_for_each(lhp,base) {
@@ -1566,12 +1615,14 @@ int d_validate(struct dentry *dentry, st
*/
if (dentry == hlist_entry(lhp, struct dentry, d_hash)) {
spin_unlock(&dcache_hash_lock);
- __dget_locked(dentry);
+ __dget_locked_dlock(dentry);
+ spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
return 1;
}
}
spin_unlock(&dcache_hash_lock);
+ spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
out:
return 0;
@@ -1608,7 +1659,7 @@ void d_delete(struct dentry * dentry)
spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
isdir = S_ISDIR(dentry->d_inode->i_mode);
- if (atomic_read(&dentry->d_count) == 1) {
+ if (dentry->d_count == 1) {
dentry->d_flags &= ~DCACHE_CANT_MOUNT;
dentry_iput(dentry);
fsnotify_nameremove(dentry, isdir);
@@ -2314,11 +2365,15 @@ resume:
this_parent = dentry;
goto repeat;
}
- atomic_dec(&dentry->d_count);
+ spin_lock(&dentry->d_lock);
+ dentry->d_count--;
+ spin_unlock(&dentry->d_lock);
}
if (this_parent != root) {
next = this_parent->d_u.d_child.next;
- atomic_dec(&this_parent->d_count);
+ spin_lock(&this_parent->d_lock);
+ this_parent->d_count--;
+ spin_unlock(&this_parent->d_lock);
this_parent = this_parent->d_parent;
goto resume;
}
Index: linux-2.6/include/linux/dcache.h
===================================================================
--- linux-2.6.orig/include/linux/dcache.h
+++ linux-2.6/include/linux/dcache.h
@@ -87,7 +87,7 @@ full_name_hash(const unsigned char *name
#endif

struct dentry {
- atomic_t d_count;
+ unsigned int d_count; /* protected by d_lock */
unsigned int d_flags; /* protected by d_lock */
spinlock_t d_lock; /* per dentry lock */
int d_mounted;
@@ -334,17 +334,28 @@ extern char *dentry_path(struct dentry *
* needs and they take necessary precautions) you should hold dcache_lock
* and call dget_locked() instead of dget().
*/
-
+static inline struct dentry *dget_dlock(struct dentry *dentry)
+{
+ if (dentry) {
+ BUG_ON(!dentry->d_count);
+ dentry->d_count++;
+ }
+ return dentry;
+}
static inline struct dentry *dget(struct dentry *dentry)
{
if (dentry) {
- BUG_ON(!atomic_read(&dentry->d_count));
- atomic_inc(&dentry->d_count);
+ spin_lock(&dentry->d_lock);
+ dget_dlock(dentry);
+ spin_unlock(&dentry->d_lock);
}
return dentry;
}

extern struct dentry * dget_locked(struct dentry *);
+extern struct dentry * dget_locked_dlock(struct dentry *);
+
+extern struct dentry *dget_parent(struct dentry *dentry);

/**
* d_unhashed - is dentry hashed
@@ -375,16 +386,6 @@ static inline void dont_mount(struct den
spin_unlock(&dentry->d_lock);
}

-static inline struct dentry *dget_parent(struct dentry *dentry)
-{
- struct dentry *ret;
-
- spin_lock(&dentry->d_lock);
- ret = dget(dentry->d_parent);
- spin_unlock(&dentry->d_lock);
- return ret;
-}
-
extern void dput(struct dentry *);

static inline int d_mountpoint(struct dentry *dentry)
Index: linux-2.6/fs/configfs/dir.c
===================================================================
--- linux-2.6.orig/fs/configfs/dir.c
+++ linux-2.6/fs/configfs/dir.c
@@ -399,8 +399,7 @@ static void remove_dir(struct dentry * d
if (d->d_inode)
simple_rmdir(parent->d_inode,d);

- pr_debug(" o %s removing done (%d)\n",d->d_name.name,
- atomic_read(&d->d_count));
+ pr_debug(" o %s removing done (%d)\n",d->d_name.name, d->d_count);

dput(parent);
}
Index: linux-2.6/fs/locks.c
===================================================================
--- linux-2.6.orig/fs/locks.c
+++ linux-2.6/fs/locks.c
@@ -1375,7 +1375,7 @@ int generic_setlease(struct file *filp,
if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
goto out;
if ((arg == F_WRLCK)
- && ((atomic_read(&dentry->d_count) > 1)
+ && (dentry->d_count > 1
|| (atomic_read(&inode->i_count) > 1)))
goto out;
}
Index: linux-2.6/fs/namei.c
===================================================================
--- linux-2.6.orig/fs/namei.c
+++ linux-2.6/fs/namei.c
@@ -2154,7 +2154,7 @@ void dentry_unhash(struct dentry *dentry
shrink_dcache_parent(dentry);
spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
- if (atomic_read(&dentry->d_count) == 2)
+ if (dentry->d_count == 2)
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
Index: linux-2.6/fs/autofs4/expire.c
===================================================================
--- linux-2.6.orig/fs/autofs4/expire.c
+++ linux-2.6/fs/autofs4/expire.c
@@ -198,7 +198,7 @@ static int autofs4_tree_busy(struct vfsm
else
ino_count++;

- if (atomic_read(&p->d_count) > ino_count) {
+ if (p->d_count > ino_count) {
top_ino->last_used = jiffies;
dput(p);
return 1;
@@ -347,7 +347,7 @@ struct dentry *autofs4_expire_indirect(s

/* Path walk currently on this dentry? */
ino_count = atomic_read(&ino->count) + 2;
- if (atomic_read(&dentry->d_count) > ino_count)
+ if (dentry->d_count > ino_count)
goto next;

/* Can we umount this guy */
@@ -369,7 +369,7 @@ struct dentry *autofs4_expire_indirect(s
if (!exp_leaves) {
/* Path walk currently on this dentry? */
ino_count = atomic_read(&ino->count) + 1;
- if (atomic_read(&dentry->d_count) > ino_count)
+ if (dentry->d_count > ino_count)
goto next;

if (!autofs4_tree_busy(mnt, dentry, timeout, do_now)) {
@@ -383,7 +383,7 @@ struct dentry *autofs4_expire_indirect(s
} else {
/* Path walk currently on this dentry? */
ino_count = atomic_read(&ino->count) + 1;
- if (atomic_read(&dentry->d_count) > ino_count)
+ if (dentry->d_count > ino_count)
goto next;

expired = autofs4_check_leaves(mnt, dentry, timeout, do_now);
Index: linux-2.6/fs/coda/dir.c
===================================================================
--- linux-2.6.orig/fs/coda/dir.c
+++ linux-2.6/fs/coda/dir.c
@@ -612,7 +612,7 @@ static int coda_dentry_revalidate(struct
if (cii->c_flags & C_FLUSH)
coda_flag_inode_children(inode, C_FLUSH);

- if (atomic_read(&de->d_count) > 1)
+ if (de->d_count > 1)
/* pretend it's valid, but don't change the flags */
goto out;

Index: linux-2.6/fs/ecryptfs/inode.c
===================================================================
--- linux-2.6.orig/fs/ecryptfs/inode.c
+++ linux-2.6/fs/ecryptfs/inode.c
@@ -255,7 +255,7 @@ int ecryptfs_lookup_and_interpose_lower(
ecryptfs_dentry->d_parent));
lower_inode = lower_dentry->d_inode;
fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
- BUG_ON(!atomic_read(&lower_dentry->d_count));
+ BUG_ON(!lower_dentry->d_count);
ecryptfs_set_dentry_private(ecryptfs_dentry,
kmem_cache_alloc(ecryptfs_dentry_info_cache,
GFP_KERNEL));
Index: linux-2.6/fs/nfs/dir.c
===================================================================
--- linux-2.6.orig/fs/nfs/dir.c
+++ linux-2.6/fs/nfs/dir.c
@@ -1357,7 +1357,7 @@ static int nfs_sillyrename(struct inode

dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
- atomic_read(&dentry->d_count));
+ dentry->d_count);
nfs_inc_stats(dir, NFSIOS_SILLYRENAME);

/*
@@ -1466,7 +1466,7 @@ static int nfs_unlink(struct inode *dir,

spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
- if (atomic_read(&dentry->d_count) > 1) {
+ if (dentry->d_count > 1) {
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
/* Start asynchronous writeout of the inode */
@@ -1614,7 +1614,7 @@ static int nfs_rename(struct inode *old_
dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n",
old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
new_dentry->d_parent->d_name.name, new_dentry->d_name.name,
- atomic_read(&new_dentry->d_count));
+ new_dentry->d_count);

/*
* For non-directories, check whether the target is busy and if so,
@@ -1632,7 +1632,7 @@ static int nfs_rename(struct inode *old_
rehash = new_dentry;
}

- if (atomic_read(&new_dentry->d_count) > 2) {
+ if (new_dentry->d_count > 2) {
int err;

/* copy the target dentry's name */
@@ -1655,7 +1655,7 @@ static int nfs_rename(struct inode *old_
/*
* ... prune child dentries and writebacks if needed.
*/
- if (atomic_read(&old_dentry->d_count) > 1) {
+ if (old_dentry->d_count > 1) {
if (S_ISREG(old_inode->i_mode))
nfs_wb_all(old_inode);
shrink_dcache_parent(old_dentry);
Index: linux-2.6/fs/nfsd/vfs.c
===================================================================
--- linux-2.6.orig/fs/nfsd/vfs.c
+++ linux-2.6/fs/nfsd/vfs.c
@@ -1752,8 +1752,7 @@ nfsd_rename(struct svc_rqst *rqstp, stru
goto out_dput_new;

if (svc_msnfs(ffhp) &&
- ((atomic_read(&odentry->d_count) > 1)
- || (atomic_read(&ndentry->d_count) > 1))) {
+ ((odentry->d_count > 1) || (ndentry->d_count > 1))) {
host_err = -EPERM;
goto out_dput_new;
}
@@ -1839,7 +1838,7 @@ nfsd_unlink(struct svc_rqst *rqstp, stru
if (type != S_IFDIR) { /* It's UNLINK */
#ifdef MSNFS
if ((fhp->fh_export->ex_flags & NFSEXP_MSNFS) &&
- (atomic_read(&rdentry->d_count) > 1)) {
+ (rdentry->d_count > 1)) {
host_err = -EPERM;
} else
#endif
Index: linux-2.6/fs/exportfs/expfs.c
===================================================================
--- linux-2.6.orig/fs/exportfs/expfs.c
+++ linux-2.6/fs/exportfs/expfs.c
@@ -74,12 +74,19 @@ static struct dentry *
find_disconnected_root(struct dentry *dentry)
{
dget(dentry);
+again:
spin_lock(&dentry->d_lock);
while (!IS_ROOT(dentry) &&
(dentry->d_parent->d_flags & DCACHE_DISCONNECTED)) {
struct dentry *parent = dentry->d_parent;
- dget(parent);
+
+ if (!spin_trylock(&parent->d_lock)) {
+ spin_unlock(&dentry->d_lock);
+ goto again;
+ }
+ dget_dlock(parent);
spin_unlock(&dentry->d_lock);
+ spin_unlock(&parent->d_lock);
dput(dentry);
dentry = parent;
spin_lock(&dentry->d_lock);
Index: linux-2.6/fs/notify/inotify/inotify.c
===================================================================
--- linux-2.6.orig/fs/notify/inotify/inotify.c
+++ linux-2.6/fs/notify/inotify/inotify.c
@@ -335,18 +335,28 @@ void inotify_dentry_parent_queue_event(s
if (!(dentry->d_flags & DCACHE_INOTIFY_PARENT_WATCHED))
return;

+again:
spin_lock(&dentry->d_lock);
parent = dentry->d_parent;
+ if (parent != dentry && !spin_trylock(&parent->d_lock)) {
+ spin_unlock(&dentry->d_lock);
+ goto again;
+ }
inode = parent->d_inode;

if (inotify_inode_watched(inode)) {
- dget(parent);
+ dget_dlock(parent);
spin_unlock(&dentry->d_lock);
+ if (parent != dentry)
+ spin_unlock(&parent->d_lock);
inotify_inode_queue_event(inode, mask, cookie, name,
dentry->d_inode);
dput(parent);
- } else
+ } else {
spin_unlock(&dentry->d_lock);
+ if (parent != dentry)
+ spin_unlock(&parent->d_lock);
+ }
}
EXPORT_SYMBOL_GPL(inotify_dentry_parent_queue_event);

Index: linux-2.6/fs/smbfs/dir.c
===================================================================
--- linux-2.6.orig/fs/smbfs/dir.c
+++ linux-2.6/fs/smbfs/dir.c
@@ -406,6 +406,7 @@ void
smb_renew_times(struct dentry * dentry)
{
dget(dentry);
+again:
spin_lock(&dentry->d_lock);
for (;;) {
struct dentry *parent;
@@ -414,8 +415,13 @@ smb_renew_times(struct dentry * dentry)
if (IS_ROOT(dentry))
break;
parent = dentry->d_parent;
- dget(parent);
+ if (!spin_trylock(&parent->d_lock)) {
+ spin_unlock(&dentry->d_lock);
+ goto again;
+ }
+ dget_dlock(parent);
spin_unlock(&dentry->d_lock);
+ spin_unlock(&parent->d_lock);
dput(dentry);
dentry = parent;
spin_lock(&dentry->d_lock);
Index: linux-2.6/fs/smbfs/proc.c
===================================================================
--- linux-2.6.orig/fs/smbfs/proc.c
+++ linux-2.6/fs/smbfs/proc.c
@@ -332,6 +332,7 @@ static int smb_build_path(struct smb_sb_
* and store it in reversed order [see reverse_string()]
*/
dget(entry);
+again:
spin_lock(&entry->d_lock);
while (!IS_ROOT(entry)) {
struct dentry *parent;
@@ -350,6 +351,7 @@ static int smb_build_path(struct smb_sb_
dput(entry);
return len;
}
+
reverse_string(path, len);
path += len;
if (unicode) {
@@ -361,7 +363,11 @@ static int smb_build_path(struct smb_sb_
maxlen -= len+1;

parent = entry->d_parent;
- dget(parent);
+ if (!spin_trylock(&parent->d_lock)) {
+ spin_unlock(&entry->d_lock);
+ goto again;
+ }
+ dget_dlock(parent);
spin_unlock(&entry->d_lock);
dput(entry);
entry = parent;
Index: linux-2.6/kernel/cgroup.c
===================================================================
--- linux-2.6.orig/kernel/cgroup.c
+++ linux-2.6/kernel/cgroup.c
@@ -3545,9 +3545,7 @@ again:
list_del(&cgrp->sibling);
cgroup_unlock_hierarchy(cgrp->root);

- spin_lock(&cgrp->dentry->d_lock);
d = dget(cgrp->dentry);
- spin_unlock(&d->d_lock);

cgroup_d_remove_dir(d);
dput(d);
Index: linux-2.6/arch/powerpc/platforms/cell/spufs/inode.c
===================================================================
--- linux-2.6.orig/arch/powerpc/platforms/cell/spufs/inode.c
+++ linux-2.6/arch/powerpc/platforms/cell/spufs/inode.c
@@ -161,7 +161,7 @@ static void spufs_prune_dir(struct dentr
spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
if (!(d_unhashed(dentry)) && dentry->d_inode) {
- dget_locked(dentry);
+ dget_locked_dlock(dentry);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
simple_unlink(dir->d_inode, dentry);
Index: linux-2.6/drivers/infiniband/hw/ipath/ipath_fs.c
===================================================================
--- linux-2.6.orig/drivers/infiniband/hw/ipath/ipath_fs.c
+++ linux-2.6/drivers/infiniband/hw/ipath/ipath_fs.c
@@ -276,7 +276,7 @@ static int remove_file(struct dentry *pa
spin_lock(&dcache_lock);
spin_lock(&tmp->d_lock);
if (!(d_unhashed(tmp) && tmp->d_inode)) {
- dget_locked(tmp);
+ dget_locked_dlock(tmp);
__d_drop(tmp);
spin_unlock(&tmp->d_lock);
spin_unlock(&dcache_lock);
Index: linux-2.6/fs/configfs/inode.c
===================================================================
--- linux-2.6.orig/fs/configfs/inode.c
+++ linux-2.6/fs/configfs/inode.c
@@ -252,7 +252,7 @@ void configfs_drop_dentry(struct configf
spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
if (!(d_unhashed(dentry) && dentry->d_inode)) {
- dget_locked(dentry);
+ dget_locked_dlock(dentry);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
Index: linux-2.6/fs/notify/fsnotify.c
===================================================================
--- linux-2.6.orig/fs/notify/fsnotify.c
+++ linux-2.6/fs/notify/fsnotify.c
@@ -88,13 +88,18 @@ void __fsnotify_parent(struct dentry *de
if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
return;

+again:
spin_lock(&dentry->d_lock);
parent = dentry->d_parent;
+ if (parent != dentry && !spin_trylock(&parent->d_lock)) {
+ spin_unlock(&dentry->d_lock);
+ goto again;
+ }
p_inode = parent->d_inode;

if (fsnotify_inode_watches_children(p_inode)) {
if (p_inode->i_fsnotify_mask & mask) {
- dget(parent);
+ dget_dlock(parent);
send = true;
}
} else {
@@ -104,11 +109,13 @@ void __fsnotify_parent(struct dentry *de
* children and update their d_flags to let them know p_inode
* doesn't care about them any more.
*/
- dget(parent);
+ dget_dlock(parent);
should_update_children = true;
}

spin_unlock(&dentry->d_lock);
+ if (parent != dentry)
+ spin_unlock(&parent->d_lock);

if (send) {
/* we are notifying a parent so come up with the new mask which
Index: linux-2.6/fs/ceph/dir.c
===================================================================
--- linux-2.6.orig/fs/ceph/dir.c
+++ linux-2.6/fs/ceph/dir.c
@@ -149,7 +149,9 @@ more:
di = ceph_dentry(dentry);
}

- atomic_inc(&dentry->d_count);
+ spin_lock(&dentry->d_lock);
+ dentry->d_count++;
+ spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
spin_unlock(&inode->i_lock);

Index: linux-2.6/fs/ceph/inode.c
===================================================================
--- linux-2.6.orig/fs/ceph/inode.c
+++ linux-2.6/fs/ceph/inode.c
@@ -863,8 +863,8 @@ static struct dentry *splice_dentry(stru
} else if (realdn) {
dout("dn %p (%d) spliced with %p (%d) "
"inode %p ino %llx.%llx\n",
- dn, atomic_read(&dn->d_count),
- realdn, atomic_read(&realdn->d_count),
+ dn, dn->d_count,
+ realdn, realdn->d_count,
realdn->d_inode, ceph_vinop(realdn->d_inode));
dput(dn);
dn = realdn;
Index: linux-2.6/fs/ceph/mds_client.c
===================================================================
--- linux-2.6.orig/fs/ceph/mds_client.c
+++ linux-2.6/fs/ceph/mds_client.c
@@ -1371,7 +1371,7 @@ retry:
*base = ceph_ino(temp->d_inode);
*plen = len;
dout("build_path on %p %d built %llx '%.*s'\n",
- dentry, atomic_read(&dentry->d_count), *base, len, path);
+ dentry, dentry->d_count, *base, len, path);
return path;
}

Index: linux-2.6/drivers/infiniband/hw/qib/qib_fs.c
===================================================================
--- linux-2.6.orig/drivers/infiniband/hw/qib/qib_fs.c
+++ linux-2.6/drivers/infiniband/hw/qib/qib_fs.c
@@ -454,7 +454,7 @@ static int remove_file(struct dentry *pa
spin_lock(&dcache_lock);
spin_lock(&tmp->d_lock);
if (!(d_unhashed(tmp) && tmp->d_inode)) {
- dget_locked(tmp);
+ dget_locked_dlock(tmp);
__d_drop(tmp);
spin_unlock(&tmp->d_lock);
spin_unlock(&dcache_lock);


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