dcache_lock no longer protects anything. remove it.
Signed-off-by: Nick Piggin <npiggin@xxxxxxxxx>
---
Documentation/filesystems/Locking | 16 +-
Documentation/filesystems/dentry-locking.txt | 40 +++---
Documentation/filesystems/porting | 8 +
arch/powerpc/platforms/cell/spufs/inode.c | 5
drivers/infiniband/hw/ipath/ipath_fs.c | 6 -
drivers/infiniband/hw/qib/qib_fs.c | 3
drivers/staging/pohmelfs/path_entry.c | 2
drivers/staging/smbfs/cache.c | 4
drivers/usb/core/inode.c | 3
fs/9p/vfs_inode.c | 2
fs/affs/amigaffs.c | 2
fs/autofs4/autofs_i.h | 3
fs/autofs4/expire.c | 10 -
fs/autofs4/root.c | 44 +++----
fs/autofs4/waitq.c | 7 -
fs/ceph/dir.c | 6 -
fs/ceph/inode.c | 4
fs/cifs/inode.c | 3
fs/coda/cache.c | 2
fs/configfs/configfs_internal.h | 2
fs/configfs/inode.c | 6 -
fs/dcache.c | 162 ++++-----------------------
fs/exportfs/expfs.c | 4
fs/libfs.c | 8 -
fs/namei.c | 9 -
fs/ncpfs/dir.c | 18 +--
fs/ncpfs/ncplib_kernel.h | 4
fs/nfs/dir.c | 3
fs/nfs/getroot.c | 2
fs/nfs/namespace.c | 3
fs/notify/fsnotify.c | 2
fs/ocfs2/dcache.c | 2
include/linux/dcache.h | 7 -
include/linux/fs.h | 6 -
include/linux/fsnotify.h | 2
include/linux/fsnotify_backend.h | 11 +
include/linux/namei.h | 1
kernel/cgroup.c | 6 -
mm/filemap.c | 3
security/selinux/selinuxfs.c | 4
40 files changed, 120 insertions(+), 315 deletions(-)
Index: linux-2.6/fs/dcache.c
===================================================================
--- linux-2.6.orig/fs/dcache.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/dcache.c 2010-11-17 01:05:40.000000000 +1100
@@ -54,11 +54,10 @@
* - d_alias, d_inode
*
* Ordering:
- * dcache_lock
- * dcache_inode_lock
- * dentry->d_lock
- * dcache_lru_lock
- * dcache_hash_lock
+ * dcache_inode_lock
+ * dentry->d_lock
+ * dcache_lru_lock
+ * dcache_hash_lock
*
* If there is an ancestor relationship:
* dentry->d_parent->...->d_parent->d_lock
@@ -77,13 +76,11 @@ EXPORT_SYMBOL_GPL(sysctl_vfs_cache_press
__cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_inode_lock);
__cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_hash_lock);
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_lru_lock);
-__cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_lock);
__cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock);
EXPORT_SYMBOL(rename_lock);
EXPORT_SYMBOL(dcache_inode_lock);
EXPORT_SYMBOL(dcache_hash_lock);
-EXPORT_SYMBOL(dcache_lock);
static struct kmem_cache *dentry_cache __read_mostly;
@@ -133,7 +130,7 @@ static void __d_free(struct rcu_head *he
}
/*
- * no dcache_lock, please.
+ * no locks, please.
*/
static void d_free(struct dentry *dentry)
{
@@ -156,7 +153,6 @@ static void d_free(struct dentry *dentry
static void dentry_iput(struct dentry * dentry)
__releases(dentry->d_lock)
__releases(dcache_inode_lock)
- __releases(dcache_lock)
{
struct inode *inode = dentry->d_inode;
if (inode) {
@@ -164,7 +160,6 @@ static void dentry_iput(struct dentry *
list_del_init(&dentry->d_alias);
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
if (!inode->i_nlink)
fsnotify_inoderemove(inode);
if (dentry->d_op && dentry->d_op->d_iput)
@@ -174,7 +169,6 @@ static void dentry_iput(struct dentry *
} else {
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
}
}
@@ -229,14 +223,13 @@ static void dentry_lru_move_tail(struct
*
* If this is the root of the dentry tree, return NULL.
*
- * dcache_lock and d_lock and d_parent->d_lock must be held by caller, and
- * are dropped by d_kill.
+ * dentry->d_lock and parent->d_lock must be held by caller, and are dropped by
+ * d_kill.
*/
static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent)
__releases(dentry->d_lock)
__releases(parent->d_lock)
__releases(dcache_inode_lock)
- __releases(dcache_lock)
{
dentry->d_parent = NULL;
list_del(&dentry->d_u.d_child);
@@ -295,21 +288,10 @@ void dput(struct dentry *dentry)
else
parent = dentry->d_parent;
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.
- */
-drop1:
- spin_unlock(&dentry->d_lock);
- goto repeat;
- }
if (!spin_trylock(&dcache_inode_lock)) {
drop2:
- spin_unlock(&dcache_lock);
- goto drop1;
+ spin_unlock(&dentry->d_lock);
+ goto repeat;
}
if (parent && !spin_trylock(&parent->d_lock)) {
spin_unlock(&dcache_inode_lock);
@@ -321,7 +303,6 @@ void dput(struct dentry *dentry)
spin_unlock(&dentry->d_lock);
if (parent)
spin_unlock(&parent->d_lock);
- spin_unlock(&dcache_lock);
return;
}
@@ -345,7 +326,6 @@ void dput(struct dentry *dentry)
if (parent)
spin_unlock(&parent->d_lock);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
return;
unhash_it:
@@ -376,11 +356,9 @@ int d_invalidate(struct dentry * dentry)
/*
* If it's already been dropped, return OK.
*/
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
if (d_unhashed(dentry)) {
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
return 0;
}
/*
@@ -389,9 +367,7 @@ int d_invalidate(struct dentry * dentry)
*/
if (!list_empty(&dentry->d_subdirs)) {
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
shrink_dcache_parent(dentry);
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
}
@@ -408,19 +384,17 @@ int d_invalidate(struct dentry * dentry)
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);
return -EBUSY;
}
}
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
return 0;
}
EXPORT_SYMBOL(d_invalidate);
-/* This must be called with dcache_lock and d_lock held */
+/* This must be called with d_lock held */
static inline struct dentry * __dget_locked_dlock(struct dentry *dentry)
{
dentry->d_count++;
@@ -428,7 +402,7 @@ static inline struct dentry * __dget_loc
return dentry;
}
-/* This should be called _only_ with dcache_lock held */
+/* This must be called with d_lock held */
static inline struct dentry * __dget_locked(struct dentry *dentry)
{
spin_lock(&dentry->d_lock);
@@ -538,11 +512,9 @@ struct dentry *d_find_alias(struct inode
struct dentry *de = NULL;
if (!list_empty(&inode->i_dentry)) {
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
de = __d_find_alias(inode, 0);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
}
return de;
}
@@ -556,7 +528,6 @@ void d_prune_aliases(struct inode *inode
{
struct dentry *dentry;
restart:
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
spin_lock(&dentry->d_lock);
@@ -565,14 +536,12 @@ void d_prune_aliases(struct inode *inode
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
dput(dentry);
goto restart;
}
spin_unlock(&dentry->d_lock);
}
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
}
EXPORT_SYMBOL(d_prune_aliases);
@@ -588,17 +557,14 @@ static void prune_one_dentry(struct dent
__releases(dentry->d_lock)
__releases(parent->d_lock)
__releases(dcache_inode_lock)
- __releases(dcache_lock)
{
__d_drop(dentry);
dentry = d_kill(dentry, parent);
/*
- * Prune ancestors. Locking is simpler than in dput(),
- * because dcache_lock needs to be taken anyway.
+ * Prune ancestors.
*/
while (dentry) {
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
again:
spin_lock(&dentry->d_lock);
@@ -616,7 +582,6 @@ static void prune_one_dentry(struct dent
spin_unlock(&parent->d_lock);
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
return;
}
@@ -665,8 +630,7 @@ static void shrink_dentry_list(struct li
spin_unlock(&dcache_lru_lock);
prune_one_dentry(dentry, parent);
- /* dcache_lock, dcache_inode_lock and dentry->d_lock dropped */
- spin_lock(&dcache_lock);
+ /* dcache_inode_lock and dentry->d_lock dropped */
spin_lock(&dcache_inode_lock);
spin_lock(&dcache_lru_lock);
}
@@ -688,7 +652,6 @@ static void __shrink_dcache_sb(struct su
LIST_HEAD(tmp);
int cnt = *count;
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
relock:
spin_lock(&dcache_lru_lock);
@@ -719,7 +682,6 @@ static void __shrink_dcache_sb(struct su
if (!--cnt)
break;
}
- /* XXX: re-add cond_resched_lock when dcache_lock goes away */
}
*count = cnt;
@@ -729,7 +691,6 @@ static void __shrink_dcache_sb(struct su
list_splice(&referenced, &sb->s_dentry_lru);
spin_unlock(&dcache_lru_lock);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
}
/**
@@ -751,7 +712,6 @@ static void prune_dcache(int count)
if (unused == 0 || count == 0)
return;
- spin_lock(&dcache_lock);
if (count >= unused)
prune_ratio = 1;
else
@@ -788,11 +748,9 @@ static void prune_dcache(int count)
if (down_read_trylock(&sb->s_umount)) {
if ((sb->s_root != NULL) &&
(!list_empty(&sb->s_dentry_lru))) {
- spin_unlock(&dcache_lock);
__shrink_dcache_sb(sb, &w_count,
DCACHE_REFERENCED);
pruned -= w_count;
- spin_lock(&dcache_lock);
}
up_read(&sb->s_umount);
}
@@ -808,7 +766,6 @@ static void prune_dcache(int count)
if (p)
__put_super(p);
spin_unlock(&sb_lock);
- spin_unlock(&dcache_lock);
}
/**
@@ -822,7 +779,6 @@ void shrink_dcache_sb(struct super_block
{
LIST_HEAD(tmp);
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
spin_lock(&dcache_lru_lock);
while (!list_empty(&sb->s_dentry_lru)) {
@@ -831,7 +787,6 @@ void shrink_dcache_sb(struct super_block
}
spin_unlock(&dcache_lru_lock);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
}
EXPORT_SYMBOL(shrink_dcache_sb);
@@ -848,12 +803,10 @@ static void shrink_dcache_for_umount_sub
BUG_ON(!IS_ROOT(dentry));
/* detach this root from the system */
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
dentry_lru_del(dentry);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
for (;;) {
/* descend to the first leaf in the current subtree */
@@ -862,7 +815,6 @@ static void shrink_dcache_for_umount_sub
/* this is a branch with children - detach all of them
* from the system in one go */
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
list_for_each_entry(loop, &dentry->d_subdirs,
d_u.d_child) {
@@ -873,7 +825,6 @@ static void shrink_dcache_for_umount_sub
spin_unlock(&loop->d_lock);
}
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
/* move to the first child */
dentry = list_entry(dentry->d_subdirs.next,
@@ -940,8 +891,7 @@ static void shrink_dcache_for_umount_sub
/*
* destroy the dentries attached to a superblock on unmounting
- * - we don't need to use dentry->d_lock, and only need dcache_lock when
- * removing the dentry from the system lists and hashes because:
+ * - we don't need to use dentry->d_lock because:
* - the superblock is detached from all mountings and open files, so the
* dentry trees will not be rearranged by the VFS
* - s_umount is write-locked, so the memory pressure shrinker will ignore
@@ -992,7 +942,6 @@ int have_submounts(struct dentry *parent
this_parent = parent;
seq = read_seqbegin(&rename_lock);
- spin_lock(&dcache_lock);
if (d_mountpoint(parent))
goto positive;
spin_lock(&this_parent->d_lock);
@@ -1038,7 +987,6 @@ int have_submounts(struct dentry *parent
if (this_parent != child->d_parent ||
read_seqretry(&rename_lock, seq)) {
spin_unlock(&this_parent->d_lock);
- spin_unlock(&dcache_lock);
rcu_read_unlock();
goto rename_retry;
}
@@ -1047,12 +995,10 @@ int have_submounts(struct dentry *parent
goto resume;
}
spin_unlock(&this_parent->d_lock);
- spin_unlock(&dcache_lock);
if (read_seqretry(&rename_lock, seq))
goto rename_retry;
return 0; /* No mount points found in tree */
positive:
- spin_unlock(&dcache_lock);
if (read_seqretry(&rename_lock, seq))
goto rename_retry;
return 1;
@@ -1084,7 +1030,6 @@ static int select_parent(struct dentry *
this_parent = parent;
seq = read_seqbegin(&rename_lock);
- spin_lock(&dcache_lock);
spin_lock(&this_parent->d_lock);
repeat:
next = this_parent->d_subdirs.next;
@@ -1148,7 +1093,6 @@ static int select_parent(struct dentry *
if (this_parent != child->d_parent ||
read_seqretry(&rename_lock, seq)) {
spin_unlock(&this_parent->d_lock);
- spin_unlock(&dcache_lock);
rcu_read_unlock();
goto rename_retry;
}
@@ -1158,7 +1102,6 @@ static int select_parent(struct dentry *
}
out:
spin_unlock(&this_parent->d_lock);
- spin_unlock(&dcache_lock);
if (read_seqretry(&rename_lock, seq))
goto rename_retry;
return found;
@@ -1263,7 +1206,6 @@ struct dentry *d_alloc(struct dentry * p
INIT_LIST_HEAD(&dentry->d_u.d_child);
if (parent) {
- spin_lock(&dcache_lock);
spin_lock(&parent->d_lock);
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
dentry->d_parent = dget_dlock(parent);
@@ -1271,7 +1213,6 @@ struct dentry *d_alloc(struct dentry * p
list_add(&dentry->d_u.d_child, &parent->d_subdirs);
spin_unlock(&dentry->d_lock);
spin_unlock(&parent->d_lock);
- spin_unlock(&dcache_lock);
}
percpu_counter_inc(&nr_dentry);
@@ -1291,7 +1232,6 @@ struct dentry *d_alloc_name(struct dentr
}
EXPORT_SYMBOL(d_alloc_name);
-/* the caller must hold dcache_lock */
static void __d_instantiate(struct dentry *dentry, struct inode *inode)
{
spin_lock(&dentry->d_lock);
@@ -1320,11 +1260,9 @@ static void __d_instantiate(struct dentr
void d_instantiate(struct dentry *entry, struct inode * inode)
{
BUG_ON(!list_empty(&entry->d_alias));
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
__d_instantiate(entry, inode);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
security_d_instantiate(entry, inode);
}
EXPORT_SYMBOL(d_instantiate);
@@ -1387,11 +1325,9 @@ struct dentry *d_instantiate_unique(stru
BUG_ON(!list_empty(&entry->d_alias));
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
result = __d_instantiate_unique(entry, inode);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
if (!result) {
security_d_instantiate(entry, inode);
@@ -1480,12 +1416,11 @@ struct dentry *d_obtain_alias(struct ino
}
tmp->d_parent = tmp; /* make sure dput doesn't croak */
- spin_lock(&dcache_lock);
+
spin_lock(&dcache_inode_lock);
res = __d_find_alias(inode, 0);
if (res) {
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
dput(tmp);
goto out_iput;
}
@@ -1503,7 +1438,6 @@ struct dentry *d_obtain_alias(struct ino
spin_unlock(&tmp->d_lock);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
return tmp;
out_iput:
@@ -1533,21 +1467,18 @@ struct dentry *d_splice_alias(struct ino
struct dentry *new = NULL;
if (inode && S_ISDIR(inode->i_mode)) {
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
new = __d_find_alias(inode, 1);
if (new) {
BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED));
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
security_d_instantiate(new, inode);
d_move(new, dentry);
iput(inode);
} else {
- /* already taking dcache_lock, so d_add() by hand */
+ /* already taking dcache_inode_lock, so d_add() by hand */
__d_instantiate(dentry, inode);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
security_d_instantiate(dentry, inode);
d_rehash(dentry);
}
@@ -1620,12 +1551,10 @@ struct dentry *d_add_ci(struct dentry *d
* Negative dentry: instantiate it unless the inode is a directory and
* already has a dentry.
*/
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
if (!S_ISDIR(inode->i_mode) || list_empty(&inode->i_dentry)) {
__d_instantiate(found, inode);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
security_d_instantiate(found, inode);
return found;
}
@@ -1637,7 +1566,6 @@ struct dentry *d_add_ci(struct dentry *d
new = list_entry(inode->i_dentry.next, struct dentry, d_alias);
dget_locked(new);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
security_d_instantiate(found, inode);
d_move(new, found);
iput(inode);
@@ -1808,7 +1736,6 @@ int d_validate(struct dentry *dentry, st
{
struct dentry *child;
- spin_lock(&dcache_lock);
spin_lock(&dparent->d_lock);
list_for_each_entry(child, &dparent->d_subdirs, d_u.d_child) {
if (dentry == child) {
@@ -1816,12 +1743,10 @@ int d_validate(struct dentry *dentry, st
__dget_locked_dlock(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&dparent->d_lock);
- spin_unlock(&dcache_lock);
return 1;
}
}
spin_unlock(&dparent->d_lock);
- spin_unlock(&dcache_lock);
return 0;
}
@@ -1854,7 +1779,6 @@ void d_delete(struct dentry * dentry)
/*
* Are we the only user?
*/
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
spin_lock(&dentry->d_lock);
isdir = S_ISDIR(dentry->d_inode->i_mode);
@@ -1870,7 +1794,6 @@ void d_delete(struct dentry * dentry)
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
fsnotify_nameremove(dentry, isdir);
}
@@ -1897,13 +1820,11 @@ static void _d_rehash(struct dentry * en
void d_rehash(struct dentry * entry)
{
- spin_lock(&dcache_lock);
spin_lock(&entry->d_lock);
spin_lock(&dcache_hash_lock);
_d_rehash(entry);
spin_unlock(&dcache_hash_lock);
spin_unlock(&entry->d_lock);
- spin_unlock(&dcache_lock);
}
EXPORT_SYMBOL(d_rehash);
@@ -1972,14 +1893,14 @@ static void switch_names(struct dentry *
*/
/*
- * d_move_locked - move a dentry
+ * d_move - move a dentry
* @dentry: entry to move
* @target: new dentry
*
* Update the dcache to reflect the move of a file name. Negative
* dcache entries should not be moved in this way.
*/
-static void d_move_locked(struct dentry * dentry, struct dentry * target)
+void d_move(struct dentry * dentry, struct dentry * target)
{
if (!dentry->d_inode)
printk(KERN_WARNING "VFS: moving negative dcache entry\n");
@@ -2049,22 +1970,6 @@ static void d_move_locked(struct dentry
spin_unlock(&dentry->d_lock);
write_sequnlock(&rename_lock);
}
-
-/**
- * d_move - move a dentry
- * @dentry: entry to move
- * @target: new dentry
- *
- * Update the dcache to reflect the move of a file name. Negative
- * dcache entries should not be moved in this way.
- */
-
-void d_move(struct dentry * dentry, struct dentry * target)
-{
- spin_lock(&dcache_lock);
- d_move_locked(dentry, target);
- spin_unlock(&dcache_lock);
-}
EXPORT_SYMBOL(d_move);
/**
@@ -2090,13 +1995,12 @@ struct dentry *d_ancestor(struct dentry
* This helper attempts to cope with remotely renamed directories
*
* It assumes that the caller is already holding
- * dentry->d_parent->d_inode->i_mutex and the dcache_lock
+ * dentry->d_parent->d_inode->i_mutex and the dcache_inode_lock
*
* Note: If ever the locking in lock_rename() changes, then please
* remember to update this too...
*/
static struct dentry *__d_unalias(struct dentry *dentry, struct dentry *alias)
- __releases(dcache_lock)
__releases(dcache_inode_lock)
{
struct mutex *m1 = NULL, *m2 = NULL;
@@ -2120,11 +2024,10 @@ static struct dentry *__d_unalias(struct
goto out_err;
m2 = &alias->d_parent->d_inode->i_mutex;
out_unalias:
- d_move_locked(alias, dentry);
+ d_move(alias, dentry);
ret = alias;
out_err:
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
if (m2)
mutex_unlock(m2);
if (m1)
@@ -2188,7 +2091,6 @@ struct dentry *d_materialise_unique(stru
BUG_ON(!d_unhashed(dentry));
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
if (!inode) {
@@ -2203,6 +2105,11 @@ struct dentry *d_materialise_unique(stru
/* Does an aliased dentry already exist? */
alias = __d_find_alias(inode, 0);
if (alias) {
+ /*
+ * XXX: after dcache_lock removal, we no longer
+ * guarantee a !d_unhashed alias here. Is that going to
+ * be a problem?
+ */
actual = alias;
/* Is this an anonymous mountpoint that we could splice
* into our tree? */
@@ -2234,7 +2141,6 @@ struct dentry *d_materialise_unique(stru
spin_unlock(&dcache_hash_lock);
spin_unlock(&actual->d_lock);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
out_nolock:
if (actual == dentry) {
security_d_instantiate(dentry, inode);
@@ -2246,7 +2152,6 @@ struct dentry *d_materialise_unique(stru
shouldnt_be_hashed:
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
BUG();
}
EXPORT_SYMBOL_GPL(d_materialise_unique);
@@ -2360,11 +2265,9 @@ char *__d_path(const struct path *path,
int error;
prepend(&res, &buflen, "\0", 1);
- spin_lock(&dcache_lock);
write_seqlock(&rename_lock);
error = prepend_path(path, root, &res, &buflen);
write_sequnlock(&rename_lock);
- spin_unlock(&dcache_lock);
if (error)
return ERR_PTR(error);
@@ -2426,14 +2329,12 @@ char *d_path(const struct path *path, ch
return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
get_fs_root(current->fs, &root);
- spin_lock(&dcache_lock);
write_seqlock(&rename_lock);
tmp = root;
error = path_with_deleted(path, &tmp, &res, &buflen);
if (error)
res = ERR_PTR(error);
write_sequnlock(&rename_lock);
- spin_unlock(&dcache_lock);
path_put(&root);
return res;
}
@@ -2459,14 +2360,12 @@ char *d_path_with_unreachable(const stru
return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
get_fs_root(current->fs, &root);
- spin_lock(&dcache_lock);
write_seqlock(&rename_lock);
tmp = root;
error = path_with_deleted(path, &tmp, &res, &buflen);
if (!error && !path_equal(&tmp, &root))
error = prepend_unreachable(&res, &buflen);
write_sequnlock(&rename_lock);
- spin_unlock(&dcache_lock);
path_put(&root);
if (error)
res = ERR_PTR(error);
@@ -2533,11 +2432,9 @@ char *dentry_path_raw(struct dentry *den
{
char *retval;
- spin_lock(&dcache_lock);
write_seqlock(&rename_lock);
retval = __dentry_path(dentry, buf, buflen);
write_sequnlock(&rename_lock);
- spin_unlock(&dcache_lock);
return retval;
}
@@ -2548,7 +2445,6 @@ char *dentry_path(struct dentry *dentry,
char *p = NULL;
char *retval;
- spin_lock(&dcache_lock);
write_seqlock(&rename_lock);
if (d_unlinked(dentry)) {
p = buf + buflen;
@@ -2558,12 +2454,10 @@ char *dentry_path(struct dentry *dentry,
}
retval = __dentry_path(dentry, buf, buflen);
write_sequnlock(&rename_lock);
- spin_unlock(&dcache_lock);
if (!IS_ERR(retval) && p)
*p = '/'; /* restore '/' overriden with '\0' */
return retval;
Elong:
- spin_unlock(&dcache_lock);
return ERR_PTR(-ENAMETOOLONG);
}
@@ -2597,7 +2491,6 @@ SYSCALL_DEFINE2(getcwd, char __user *, b
get_fs_root_and_pwd(current->fs, &root, &pwd);
error = -ENOENT;
- spin_lock(&dcache_lock);
write_seqlock(&rename_lock);
if (!d_unlinked(pwd.dentry)) {
unsigned long len;
@@ -2608,7 +2501,6 @@ SYSCALL_DEFINE2(getcwd, char __user *, b
prepend(&cwd, &buflen, "\0", 1);
error = prepend_path(&pwd, &tmp, &cwd, &buflen);
write_sequnlock(&rename_lock);
- spin_unlock(&dcache_lock);
if (error)
goto out;
@@ -2629,7 +2521,6 @@ SYSCALL_DEFINE2(getcwd, char __user *, b
}
} else {
write_sequnlock(&rename_lock);
- spin_unlock(&dcache_lock);
}
out:
@@ -2715,7 +2606,6 @@ void d_genocide(struct dentry *root)
rename_retry:
this_parent = root;
seq = read_seqbegin(&rename_lock);
- spin_lock(&dcache_lock);
spin_lock(&this_parent->d_lock);
repeat:
next = this_parent->d_subdirs.next;
@@ -2762,7 +2652,6 @@ void d_genocide(struct dentry *root)
if (this_parent != child->d_parent ||
read_seqretry(&rename_lock, seq)) {
spin_unlock(&this_parent->d_lock);
- spin_unlock(&dcache_lock);
rcu_read_unlock();
goto rename_retry;
}
@@ -2771,7 +2660,6 @@ void d_genocide(struct dentry *root)
goto resume;
}
spin_unlock(&this_parent->d_lock);
- spin_unlock(&dcache_lock);
if (read_seqretry(&rename_lock, seq))
goto rename_retry;
}
Index: linux-2.6/fs/namei.c
===================================================================
--- linux-2.6.orig/fs/namei.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/namei.c 2010-11-17 00:52:37.000000000 +1100
@@ -612,8 +612,8 @@ int follow_up(struct path *path)
return 1;
}
-/* no need for dcache_lock, as serialization is taken care in
- * namespace.c
+/*
+ * serialization is taken care of in namespace.c
*/
static int __follow_mount(struct path *path)
{
@@ -645,9 +645,6 @@ static void follow_mount(struct path *pa
}
}
-/* no need for dcache_lock, as serialization is taken care in
- * namespace.c
- */
int follow_down(struct path *path)
{
struct vfsmount *mounted;
@@ -2128,12 +2125,10 @@ void dentry_unhash(struct dentry *dentry
{
dget(dentry);
shrink_dcache_parent(dentry);
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
if (dentry->d_count == 2)
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
}
int vfs_rmdir(struct inode *dir, struct dentry *dentry)
Index: linux-2.6/include/linux/dcache.h
===================================================================
--- linux-2.6.orig/include/linux/dcache.h 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/include/linux/dcache.h 2010-11-17 01:05:39.000000000 +1100
@@ -184,7 +184,6 @@ struct dentry_operations {
extern spinlock_t dcache_inode_lock;
extern spinlock_t dcache_hash_lock;
-extern spinlock_t dcache_lock;
extern seqlock_t rename_lock;
/**
@@ -215,11 +214,9 @@ static inline void __d_drop(struct dentr
static inline void d_drop(struct dentry *dentry)
{
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
}
static inline int dname_external(struct dentry *dentry)
@@ -328,8 +325,8 @@ extern char *dentry_path(struct dentry *
* destroyed when it has references. dget() should never be
* called for dentries with zero reference counter. For these cases
* (preferably none, functions in dcache.c are sufficient for normal
- * needs and they take necessary precautions) you should hold dcache_lock
- * and call dget_locked() instead of dget().
+ * needs and they take necessary precautions) you should hold d_lock
+ * and call dget_dlock() instead of dget().
*/
static inline struct dentry *dget_dlock(struct dentry *dentry)
{
Index: linux-2.6/fs/exportfs/expfs.c
===================================================================
--- linux-2.6.orig/fs/exportfs/expfs.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/exportfs/expfs.c 2010-11-17 01:05:39.000000000 +1100
@@ -47,24 +47,20 @@ find_acceptable_alias(struct dentry *res
if (acceptable(context, result))
return result;
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
list_for_each_entry(dentry, &result->d_inode->i_dentry, d_alias) {
dget_locked(dentry);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
if (toput)
dput(toput);
if (dentry != result && acceptable(context, dentry)) {
dput(result);
return dentry;
}
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
toput = dentry;
}
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
if (toput)
dput(toput);
Index: linux-2.6/Documentation/filesystems/Locking
===================================================================
--- linux-2.6.orig/Documentation/filesystems/Locking 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/Documentation/filesystems/Locking 2010-11-17 00:52:37.000000000 +1100
@@ -22,14 +22,14 @@ be able to use diff(1).
locking rules:
none have BKL
- dcache_lock rename_lock ->d_lock may block
-d_revalidate: no no no yes
-d_hash no no no no
-d_compare: no yes no no
-d_delete: yes no yes no
-d_release: no no no yes
-d_iput: no no no yes
-d_dname: no no no no
+ rename_lock ->d_lock may block
+d_revalidate: no no yes
+d_hash no no no
+d_compare: yes no no
+d_delete: no yes no
+d_release: no no yes
+d_iput: no no yes
+d_dname: no no no
--------------------------- inode_operations ---------------------------
prototypes:
Index: linux-2.6/arch/powerpc/platforms/cell/spufs/inode.c
===================================================================
--- linux-2.6.orig/arch/powerpc/platforms/cell/spufs/inode.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/arch/powerpc/platforms/cell/spufs/inode.c 2010-11-17 01:05:39.000000000 +1100
@@ -159,21 +159,18 @@ static void spufs_prune_dir(struct dentr
mutex_lock(&dir->d_inode->i_mutex);
list_for_each_entry_safe(dentry, tmp, &dir->d_subdirs, d_u.d_child) {
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
if (!(d_unhashed(dentry)) && dentry->d_inode) {
dget_locked_dlock(dentry);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
simple_unlink(dir->d_inode, dentry);
- /* XXX: what is dcache_lock protecting here? Other
+ /* XXX: what was dcache_lock protecting here? Other
* filesystems (IB, configfs) release dcache_lock
* before unlink */
- spin_unlock(&dcache_lock);
dput(dentry);
} else {
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
}
}
shrink_dcache_parent(dir);
Index: linux-2.6/drivers/infiniband/hw/ipath/ipath_fs.c
===================================================================
--- linux-2.6.orig/drivers/infiniband/hw/ipath/ipath_fs.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/drivers/infiniband/hw/ipath/ipath_fs.c 2010-11-17 01:05:39.000000000 +1100
@@ -277,18 +277,14 @@ static int remove_file(struct dentry *pa
goto bail;
}
- spin_lock(&dcache_lock);
spin_lock(&tmp->d_lock);
if (!(d_unhashed(tmp) && tmp->d_inode)) {
dget_locked_dlock(tmp);
__d_drop(tmp);
spin_unlock(&tmp->d_lock);
- spin_unlock(&dcache_lock);
simple_unlink(parent->d_inode, tmp);
- } else {
+ } else
spin_unlock(&tmp->d_lock);
- spin_unlock(&dcache_lock);
- }
ret = 0;
bail:
Index: linux-2.6/drivers/usb/core/inode.c
===================================================================
--- linux-2.6.orig/drivers/usb/core/inode.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/drivers/usb/core/inode.c 2010-11-17 00:52:37.000000000 +1100
@@ -344,7 +344,6 @@ static int usbfs_empty (struct dentry *d
{
struct list_head *list;
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
list_for_each(list, &dentry->d_subdirs) {
struct dentry *de = list_entry(list, struct dentry, d_u.d_child);
@@ -353,13 +352,11 @@ static int usbfs_empty (struct dentry *d
if (usbfs_positive(de)) {
spin_unlock(&de->d_lock);
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
return 0;
}
spin_unlock(&de->d_lock);
}
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
return 1;
}
Index: linux-2.6/fs/affs/amigaffs.c
===================================================================
--- linux-2.6.orig/fs/affs/amigaffs.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/affs/amigaffs.c 2010-11-17 00:52:37.000000000 +1100
@@ -128,7 +128,6 @@ affs_fix_dcache(struct dentry *dentry, u
void *data = dentry->d_fsdata;
struct list_head *head, *next;
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
head = &inode->i_dentry;
next = head->next;
@@ -141,7 +140,6 @@ affs_fix_dcache(struct dentry *dentry, u
next = next->next;
}
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
}
Index: linux-2.6/fs/coda/cache.c
===================================================================
--- linux-2.6.orig/fs/coda/cache.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/coda/cache.c 2010-11-17 00:52:37.000000000 +1100
@@ -93,7 +93,6 @@ static void coda_flag_children(struct de
struct list_head *child;
struct dentry *de;
- spin_lock(&dcache_lock);
spin_lock(&parent->d_lock);
list_for_each(child, &parent->d_subdirs)
{
@@ -104,7 +103,6 @@ static void coda_flag_children(struct de
coda_flag_inode(de->d_inode, flag);
}
spin_unlock(&parent->d_lock);
- spin_unlock(&dcache_lock);
return;
}
Index: linux-2.6/fs/configfs/configfs_internal.h
===================================================================
--- linux-2.6.orig/fs/configfs/configfs_internal.h 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/configfs/configfs_internal.h 2010-11-17 00:52:37.000000000 +1100
@@ -120,7 +120,6 @@ static inline struct config_item *config
{
struct config_item * item = NULL;
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
if (!d_unhashed(dentry)) {
struct configfs_dirent * sd = dentry->d_fsdata;
@@ -131,7 +130,6 @@ static inline struct config_item *config
item = config_item_get(sd->s_element);
}
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
return item;
}
Index: linux-2.6/fs/configfs/inode.c
===================================================================
--- linux-2.6.orig/fs/configfs/inode.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/configfs/inode.c 2010-11-17 01:05:39.000000000 +1100
@@ -250,18 +250,14 @@ void configfs_drop_dentry(struct configf
struct dentry * dentry = sd->s_dentry;
if (dentry) {
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
if (!(d_unhashed(dentry) && dentry->d_inode)) {
dget_locked_dlock(dentry);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
simple_unlink(parent->d_inode, dentry);
- } else {
+ } else
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
- }
}
}
Index: linux-2.6/fs/ncpfs/dir.c
===================================================================
--- linux-2.6.orig/fs/ncpfs/dir.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/ncpfs/dir.c 2010-11-17 01:05:39.000000000 +1100
@@ -394,7 +394,6 @@ ncp_dget_fpos(struct dentry *dentry, str
}
/* If a pointer is invalid, we search the dentry. */
- spin_lock(&dcache_lock);
spin_lock(&parent->d_lock);
next = parent->d_subdirs.next;
while (next != &parent->d_subdirs) {
@@ -405,13 +404,11 @@ ncp_dget_fpos(struct dentry *dentry, str
else
dent = NULL;
spin_unlock(&parent->d_lock);
- spin_unlock(&dcache_lock);
goto out;
}
next = next->next;
}
spin_unlock(&parent->d_lock);
- spin_unlock(&dcache_lock);
return NULL;
out:
@@ -635,21 +632,18 @@ ncp_fill_cache(struct file *filp, void *
struct inode *inode = newdent->d_inode;
/*
- * Inside ncpfs all uses of d_name are either for debugging,
- * or on functions which acquire inode mutex (mknod, creat,
- * lookup). So grab i_mutex here, to be sure. d_path
- * uses dcache_lock when generating path, so we should too.
- * And finally d_compare is protected by dentry's d_lock, so
- * here we go.
+ * Inside ncpfs all uses of d_name are either for
+ * debugging, or on functions which acquire inode mutex
+ * (mknod, creat, lookup). So grab i_mutex here, to be
+ * sure. And finally d_compare is protected by
+ * dentry's d_lock, so here we go.
*/
if (inode)
mutex_lock(&inode->i_mutex);
- spin_lock(&dcache_lock);
spin_lock(&newdent->d_lock);
memcpy((char *) newdent->d_name.name, qname.name,
- newdent->d_name.len);
+ newdent->d_name.len);
spin_unlock(&newdent->d_lock);
- spin_unlock(&dcache_lock);
if (inode)
mutex_unlock(&inode->i_mutex);
}
Index: linux-2.6/fs/ncpfs/ncplib_kernel.h
===================================================================
--- linux-2.6.orig/fs/ncpfs/ncplib_kernel.h 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/ncpfs/ncplib_kernel.h 2010-11-17 00:52:37.000000000 +1100
@@ -193,7 +193,6 @@ ncp_renew_dentries(struct dentry *parent
struct list_head *next;
struct dentry *dentry;
- spin_lock(&dcache_lock);
spin_lock(&parent->d_lock);
next = parent->d_subdirs.next;
while (next != &parent->d_subdirs) {
@@ -207,7 +206,6 @@ ncp_renew_dentries(struct dentry *parent
next = next->next;
}
spin_unlock(&parent->d_lock);
- spin_unlock(&dcache_lock);
}
static inline void
@@ -217,7 +215,6 @@ ncp_invalidate_dircache_entries(struct d
struct list_head *next;
struct dentry *dentry;
- spin_lock(&dcache_lock);
spin_lock(&parent->d_lock);
next = parent->d_subdirs.next;
while (next != &parent->d_subdirs) {
@@ -227,7 +224,6 @@ ncp_invalidate_dircache_entries(struct d
next = next->next;
}
spin_unlock(&parent->d_lock);
- spin_unlock(&dcache_lock);
}
struct ncp_cache_head {
Index: linux-2.6/fs/nfs/dir.c
===================================================================
--- linux-2.6.orig/fs/nfs/dir.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/nfs/dir.c 2010-11-17 00:52:37.000000000 +1100
@@ -1692,11 +1692,9 @@ static int nfs_unlink(struct inode *dir,
dfprintk(VFS, "NFS: unlink(%s/%ld, %s)\n", dir->i_sb->s_id,
dir->i_ino, dentry->d_name.name);
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
if (dentry->d_count > 1) {
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
/* Start asynchronous writeout of the inode */
write_inode_now(dentry->d_inode, 0);
error = nfs_sillyrename(dir, dentry);
@@ -1707,7 +1705,6 @@ static int nfs_unlink(struct inode *dir,
need_rehash = 1;
}
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
error = nfs_safe_remove(dentry);
if (!error || error == -ENOENT) {
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
Index: linux-2.6/fs/ocfs2/dcache.c
===================================================================
--- linux-2.6.orig/fs/ocfs2/dcache.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/ocfs2/dcache.c 2010-11-17 01:05:39.000000000 +1100
@@ -169,7 +169,6 @@ struct dentry *ocfs2_find_local_alias(st
struct list_head *p;
struct dentry *dentry = NULL;
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
list_for_each(p, &inode->i_dentry) {
dentry = list_entry(p, struct dentry, d_alias);
@@ -189,7 +188,6 @@ struct dentry *ocfs2_find_local_alias(st
}
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
return dentry;
}
Index: linux-2.6/kernel/cgroup.c
===================================================================
--- linux-2.6.orig/kernel/cgroup.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/kernel/cgroup.c 2010-11-17 01:05:39.000000000 +1100
@@ -874,7 +874,6 @@ static void cgroup_clear_directory(struc
struct list_head *node;
BUG_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
node = dentry->d_subdirs.next;
while (node != &dentry->d_subdirs) {
@@ -889,18 +888,15 @@ static void cgroup_clear_directory(struc
dget_locked_dlock(d);
spin_unlock(&d->d_lock);
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
d_delete(d);
simple_unlink(dentry->d_inode, d);
dput(d);
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
} else
spin_unlock(&d->d_lock);
node = dentry->d_subdirs.next;
}
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
}
/*
@@ -912,14 +908,12 @@ static void cgroup_d_remove_dir(struct d
cgroup_clear_directory(dentry);
- spin_lock(&dcache_lock);
parent = dentry->d_parent;
spin_lock(&parent->d_lock);
spin_lock(&dentry->d_lock);
list_del_init(&dentry->d_u.d_child);
spin_unlock(&dentry->d_lock);
spin_unlock(&parent->d_lock);
- spin_unlock(&dcache_lock);
remove_dir(dentry);
}
Index: linux-2.6/security/selinux/selinuxfs.c
===================================================================
--- linux-2.6.orig/security/selinux/selinuxfs.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/security/selinux/selinuxfs.c 2010-11-17 01:05:39.000000000 +1100
@@ -1145,7 +1145,6 @@ static void sel_remove_entries(struct de
{
struct list_head *node;
- spin_lock(&dcache_lock);
spin_lock(&de->d_lock);
node = de->d_subdirs.next;
while (node != &de->d_subdirs) {
@@ -1158,11 +1157,9 @@ static void sel_remove_entries(struct de
dget_locked_dlock(d);
spin_unlock(&de->d_lock);
spin_unlock(&d->d_lock);
- spin_unlock(&dcache_lock);
d_delete(d);
simple_unlink(de->d_inode, d);
dput(d);
- spin_lock(&dcache_lock);
spin_lock(&de->d_lock);
} else
spin_unlock(&d->d_lock);
@@ -1170,7 +1167,6 @@ static void sel_remove_entries(struct de
}
spin_unlock(&de->d_lock);
- spin_unlock(&dcache_lock);
}
#define BOOL_DIR_NAME "booleans"
Index: linux-2.6/fs/nfs/getroot.c
===================================================================
--- linux-2.6.orig/fs/nfs/getroot.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/nfs/getroot.c 2010-11-17 00:52:37.000000000 +1100
@@ -63,13 +63,11 @@ static int nfs_superblock_set_dummy_root
* This again causes shrink_dcache_for_umount_subtree() to
* Oops, since the test for IS_ROOT() will fail.
*/
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
spin_lock(&sb->s_root->d_lock);
list_del_init(&sb->s_root->d_alias);
spin_unlock(&sb->s_root->d_lock);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
}
return 0;
}
Index: linux-2.6/drivers/staging/pohmelfs/path_entry.c
===================================================================
--- linux-2.6.orig/drivers/staging/pohmelfs/path_entry.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/drivers/staging/pohmelfs/path_entry.c 2010-11-17 00:52:37.000000000 +1100
@@ -101,7 +101,6 @@ int pohmelfs_path_length(struct pohmelfs
d = first;
seq = read_seqbegin(&rename_lock);
rcu_read_lock();
- spin_lock(&dcache_lock);
if (!IS_ROOT(d) && d_unhashed(d))
len += UNHASHED_OBSCURE_STRING_SIZE; /* Obscure " (deleted)" string */
@@ -110,7 +109,6 @@ int pohmelfs_path_length(struct pohmelfs
len += d->d_name.len + 1; /* Plus slash */
d = d->d_parent;
}
- spin_unlock(&dcache_lock);
rcu_read_unlock();
if (read_seqretry(&rename_lock, seq))
goto rename_retry;
Index: linux-2.6/fs/nfs/namespace.c
===================================================================
--- linux-2.6.orig/fs/nfs/namespace.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/nfs/namespace.c 2010-11-17 00:52:37.000000000 +1100
@@ -60,7 +60,6 @@ char *nfs_path(const char *base,
seq = read_seqbegin(&rename_lock);
rcu_read_lock();
- spin_lock(&dcache_lock);
while (!IS_ROOT(dentry) && dentry != droot) {
namelen = dentry->d_name.len;
buflen -= namelen + 1;
@@ -71,7 +70,6 @@ char *nfs_path(const char *base,
*--end = '/';
dentry = dentry->d_parent;
}
- spin_unlock(&dcache_lock);
rcu_read_unlock();
if (read_seqretry(&rename_lock, seq))
goto rename_retry;
@@ -91,7 +89,6 @@ char *nfs_path(const char *base,
memcpy(end, base, namelen);
return end;
Elong_unlock:
- spin_unlock(&dcache_lock);
rcu_read_unlock();
if (read_seqretry(&rename_lock, seq))
goto rename_retry;
Index: linux-2.6/include/linux/fsnotify_backend.h
===================================================================
--- linux-2.6.orig/include/linux/fsnotify_backend.h 2010-11-17 00:50:48.000000000 +1100
+++ linux-2.6/include/linux/fsnotify_backend.h 2010-11-17 00:52:37.000000000 +1100
@@ -329,9 +329,15 @@ static inline void __fsnotify_update_dca
{
struct dentry *parent;
- assert_spin_locked(&dcache_lock);
assert_spin_locked(&dentry->d_lock);
+ /*
+ * Serialisation of setting PARENT_WATCHED on the dentries is provided
+ * by d_lock. If inotify_inode_watched changes after we have taken
+ * d_lock, the following __fsnotify_update_child_dentry_flags call will
+ * find our entry, so it will spin until we complete here, and update
+ * us with the new state.
+ */
parent = dentry->d_parent;
if (parent->d_inode && fsnotify_inode_watches_children(parent->d_inode))
dentry->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
@@ -341,15 +347,12 @@ static inline void __fsnotify_update_dca
/*
* fsnotify_d_instantiate - instantiate a dentry for inode
- * Called with dcache_lock held.
*/
static inline void __fsnotify_d_instantiate(struct dentry *dentry, struct inode *inode)
{
if (!inode)
return;
- assert_spin_locked(&dcache_lock);
-
spin_lock(&dentry->d_lock);
__fsnotify_update_dcache_flags(dentry);
spin_unlock(&dentry->d_lock);
Index: linux-2.6/fs/notify/fsnotify.c
===================================================================
--- linux-2.6.orig/fs/notify/fsnotify.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/notify/fsnotify.c 2010-11-17 00:52:37.000000000 +1100
@@ -59,7 +59,6 @@ void __fsnotify_update_child_dentry_flag
/* determine if the children should tell inode about their events */
watched = fsnotify_inode_watches_children(inode);
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
/* run all of the dentries associated with this inode. Since this is a
* directory, there damn well better only be one item on this list */
@@ -84,7 +83,6 @@ void __fsnotify_update_child_dentry_flag
spin_unlock(&alias->d_lock);
}
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
}
/* Notify this dentry's parent about a child's events. */
Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h 2010-11-17 00:50:47.000000000 +1100
+++ linux-2.6/include/linux/fs.h 2010-11-17 00:52:37.000000000 +1100
@@ -1377,7 +1377,7 @@ struct super_block {
#else
struct list_head s_files;
#endif
- /* s_dentry_lru and s_nr_dentry_unused are protected by dcache_lock */
+ /* s_dentry_lru, s_nr_dentry_unused protected by dcache.c lru locks */
struct list_head s_dentry_lru; /* unused dentry lru */
int s_nr_dentry_unused; /* # of dentry on lru */
@@ -2446,6 +2446,10 @@ static inline ino_t parent_ino(struct de
{
ino_t res;
+ /*
+ * Don't strictly need d_lock here? If the parent ino could change
+ * then surely we'd have a deeper race in the caller?
+ */
spin_lock(&dentry->d_lock);
res = dentry->d_parent->d_inode->i_ino;
spin_unlock(&dentry->d_lock);
Index: linux-2.6/fs/autofs4/autofs_i.h
===================================================================
--- linux-2.6.orig/fs/autofs4/autofs_i.h 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/autofs4/autofs_i.h 2010-11-17 00:52:37.000000000 +1100
@@ -16,6 +16,7 @@
#include <linux/auto_fs4.h>
#include <linux/auto_dev-ioctl.h>
#include <linux/mutex.h>
+#include <linux/spinlock.h>
#include <linux/list.h>
/* This is the range of ioctl() numbers we claim as ours */
@@ -60,6 +61,8 @@ do { \
current->pid, __func__, ##args); \
} while (0)
+extern spinlock_t autofs4_lock;
+
/* Unified info structure. This is pointed to by both the dentry and
inode structures. Each file in the filesystem has an instance of this
structure. It holds a reference to the dentry, so dentries are never
Index: linux-2.6/fs/autofs4/expire.c
===================================================================
--- linux-2.6.orig/fs/autofs4/expire.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/autofs4/expire.c 2010-11-17 00:52:37.000000000 +1100
@@ -102,7 +102,7 @@ static struct dentry *get_next_positive_
if (prev == NULL)
return dget(prev);
- spin_lock(&dcache_lock);
+ spin_lock(&autofs4_lock);
relock:
p = prev;
spin_lock(&p->d_lock);
@@ -114,7 +114,7 @@ static struct dentry *get_next_positive_
if (p == root) {
spin_unlock(&p->d_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
dput(prev);
return NULL;
}
@@ -144,7 +144,7 @@ static struct dentry *get_next_positive_
dget_dlock(ret);
spin_unlock(&ret->d_lock);
spin_unlock(&p->d_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
dput(prev);
@@ -408,13 +408,13 @@ struct dentry *autofs4_expire_indirect(s
ino->flags |= AUTOFS_INF_EXPIRING;
init_completion(&ino->expire_complete);
spin_unlock(&sbi->fs_lock);
- spin_lock(&dcache_lock);
+ spin_lock(&autofs4_lock);
spin_lock(&expired->d_parent->d_lock);
spin_lock_nested(&expired->d_lock, DENTRY_D_LOCK_NESTED);
list_move(&expired->d_parent->d_subdirs, &expired->d_u.d_child);
spin_unlock(&expired->d_lock);
spin_unlock(&expired->d_parent->d_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
return expired;
}
Index: linux-2.6/fs/autofs4/root.c
===================================================================
--- linux-2.6.orig/fs/autofs4/root.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/autofs4/root.c 2010-11-17 00:52:37.000000000 +1100
@@ -23,6 +23,8 @@
#include "autofs_i.h"
+DEFINE_SPINLOCK(autofs4_lock);
+
static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *);
static int autofs4_dir_unlink(struct inode *,struct dentry *);
static int autofs4_dir_rmdir(struct inode *,struct dentry *);
@@ -142,15 +144,15 @@ static int autofs4_dir_open(struct inode
* autofs file system so just let the libfs routines handle
* it.
*/
- spin_lock(&dcache_lock);
+ spin_lock(&autofs4_lock);
spin_lock(&dentry->d_lock);
if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) {
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
return -ENOENT;
}
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
out:
return dcache_dir_open(inode, file);
@@ -255,11 +257,11 @@ static void *autofs4_follow_link(struct
/* We trigger a mount for almost all flags */
lookup_type = autofs4_need_mount(nd->flags);
spin_lock(&sbi->fs_lock);
- spin_lock(&dcache_lock);
+ spin_lock(&autofs4_lock);
spin_lock(&dentry->d_lock);
if (!(lookup_type || ino->flags & AUTOFS_INF_PENDING)) {
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
spin_unlock(&sbi->fs_lock);
goto follow;
}
@@ -272,7 +274,7 @@ static void *autofs4_follow_link(struct
if (ino->flags & AUTOFS_INF_PENDING ||
(!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs))) {
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
spin_unlock(&sbi->fs_lock);
status = try_to_fill_dentry(dentry, nd->flags);
@@ -282,7 +284,7 @@ static void *autofs4_follow_link(struct
goto follow;
}
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
spin_unlock(&sbi->fs_lock);
follow:
/*
@@ -353,14 +355,14 @@ static int autofs4_revalidate(struct den
return 0;
/* Check for a non-mountpoint directory with no contents */
- spin_lock(&dcache_lock);
+ spin_lock(&autofs4_lock);
spin_lock(&dentry->d_lock);
if (S_ISDIR(dentry->d_inode->i_mode) &&
!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) {
DPRINTK("dentry=%p %.*s, emptydir",
dentry, dentry->d_name.len, dentry->d_name.name);
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
/* The daemon never causes a mount to trigger */
if (oz_mode)
@@ -377,7 +379,7 @@ static int autofs4_revalidate(struct den
return status;
}
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
return 1;
}
@@ -432,7 +434,7 @@ static struct dentry *autofs4_lookup_act
const unsigned char *str = name->name;
struct list_head *p, *head;
- spin_lock(&dcache_lock);
+ spin_lock(&autofs4_lock);
spin_lock(&sbi->lookup_lock);
head = &sbi->active_list;
list_for_each(p, head) {
@@ -465,14 +467,14 @@ static struct dentry *autofs4_lookup_act
dget_dlock(active);
spin_unlock(&active->d_lock);
spin_unlock(&sbi->lookup_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
return active;
}
next:
spin_unlock(&active->d_lock);
}
spin_unlock(&sbi->lookup_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
return NULL;
}
@@ -487,7 +489,7 @@ static struct dentry *autofs4_lookup_exp
const unsigned char *str = name->name;
struct list_head *p, *head;
- spin_lock(&dcache_lock);
+ spin_lock(&autofs4_lock);
spin_lock(&sbi->lookup_lock);
head = &sbi->expiring_list;
list_for_each(p, head) {
@@ -520,14 +522,14 @@ static struct dentry *autofs4_lookup_exp
dget_dlock(expiring);
spin_unlock(&expiring->d_lock);
spin_unlock(&sbi->lookup_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
return expiring;
}
next:
spin_unlock(&expiring->d_lock);
}
spin_unlock(&sbi->lookup_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
return NULL;
}
@@ -763,12 +765,12 @@ static int autofs4_dir_unlink(struct ino
dir->i_mtime = CURRENT_TIME;
- spin_lock(&dcache_lock);
+ spin_lock(&autofs4_lock);
autofs4_add_expiring(dentry);
spin_lock(&dentry->d_lock);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
return 0;
}
@@ -785,20 +787,20 @@ static int autofs4_dir_rmdir(struct inod
if (!autofs4_oz_mode(sbi))
return -EACCES;
- spin_lock(&dcache_lock);
+ spin_lock(&autofs4_lock);
spin_lock(&sbi->lookup_lock);
spin_lock(&dentry->d_lock);
if (!list_empty(&dentry->d_subdirs)) {
spin_unlock(&dentry->d_lock);
spin_unlock(&sbi->lookup_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
return -ENOTEMPTY;
}
__autofs4_add_expiring(dentry);
spin_unlock(&sbi->lookup_lock);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
if (atomic_dec_and_test(&ino->count)) {
p_ino = autofs4_dentry_ino(dentry->d_parent);
Index: linux-2.6/fs/autofs4/waitq.c
===================================================================
--- linux-2.6.orig/fs/autofs4/waitq.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/autofs4/waitq.c 2010-11-17 00:52:37.000000000 +1100
@@ -194,14 +194,15 @@ static int autofs4_getpath(struct autofs
rename_retry:
buf = *name;
len = 0;
+
seq = read_seqbegin(&rename_lock);
rcu_read_lock();
- spin_lock(&dcache_lock);
+ spin_lock(&autofs4_lock);
for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
len += tmp->d_name.len + 1;
if (!len || --len > NAME_MAX) {
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
rcu_read_unlock();
if (read_seqretry(&rename_lock, seq))
goto rename_retry;
@@ -217,7 +218,7 @@ static int autofs4_getpath(struct autofs
p -= tmp->d_name.len;
strncpy(p, tmp->d_name.name, tmp->d_name.len);
}
- spin_unlock(&dcache_lock);
+ spin_unlock(&autofs4_lock);
rcu_read_unlock();
if (read_seqretry(&rename_lock, seq))
goto rename_retry;
Index: linux-2.6/drivers/infiniband/hw/qib/qib_fs.c
===================================================================
--- linux-2.6.orig/drivers/infiniband/hw/qib/qib_fs.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/drivers/infiniband/hw/qib/qib_fs.c 2010-11-17 01:05:39.000000000 +1100
@@ -453,17 +453,14 @@ static int remove_file(struct dentry *pa
goto bail;
}
- spin_lock(&dcache_lock);
spin_lock(&tmp->d_lock);
if (!(d_unhashed(tmp) && tmp->d_inode)) {
dget_locked_dlock(tmp);
__d_drop(tmp);
spin_unlock(&tmp->d_lock);
- spin_unlock(&dcache_lock);
simple_unlink(parent->d_inode, tmp);
} else {
spin_unlock(&tmp->d_lock);
- spin_unlock(&dcache_lock);
}
ret = 0;
Index: linux-2.6/fs/ceph/dir.c
===================================================================
--- linux-2.6.orig/fs/ceph/dir.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/ceph/dir.c 2010-11-17 00:52:37.000000000 +1100
@@ -111,7 +111,6 @@ static int __dcache_readdir(struct file
dout("__dcache_readdir %p at %llu (last %p)\n", dir, filp->f_pos,
last);
- spin_lock(&dcache_lock);
spin_lock(&parent->d_lock);
/* start at beginning? */
@@ -155,7 +154,6 @@ static int __dcache_readdir(struct file
dget_dlock(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&parent->d_lock);
- spin_unlock(&dcache_lock);
dout(" %llu (%llu) dentry %p %.*s %p\n", di->offset, filp->f_pos,
dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
@@ -181,21 +179,19 @@ static int __dcache_readdir(struct file
filp->f_pos++;
- /* make sure a dentry wasn't dropped while we didn't have dcache_lock */
+ /* make sure a dentry wasn't dropped while we didn't have parent lock */
if (!ceph_i_test(dir, CEPH_I_COMPLETE)) {
dout(" lost I_COMPLETE on %p; falling back to mds\n", dir);
err = -EAGAIN;
goto out;
}
- spin_lock(&dcache_lock);
spin_lock(&parent->d_lock);
p = p->prev; /* advance to next dentry */
goto more;
out_unlock:
spin_unlock(&parent->d_lock);
- spin_unlock(&dcache_lock);
out:
if (last)
dput(last);
Index: linux-2.6/fs/ceph/inode.c
===================================================================
--- linux-2.6.orig/fs/ceph/inode.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/ceph/inode.c 2010-11-17 00:52:37.000000000 +1100
@@ -828,7 +828,6 @@ static void ceph_set_dentry_offset(struc
di->offset = ceph_inode(inode)->i_max_offset++;
spin_unlock(&inode->i_lock);
- spin_lock(&dcache_lock);
spin_lock(&dir->d_lock);
spin_lock_nested(&dn->d_lock, DENTRY_D_LOCK_NESTED);
list_move(&dn->d_u.d_child, &dir->d_subdirs);
@@ -836,7 +835,6 @@ static void ceph_set_dentry_offset(struc
dn->d_u.d_child.prev, dn->d_u.d_child.next);
spin_unlock(&dn->d_lock);
spin_unlock(&dir->d_lock);
- spin_unlock(&dcache_lock);
}
/*
@@ -1219,13 +1217,11 @@ int ceph_readdir_prepopulate(struct ceph
goto retry_lookup;
} else {
/* reorder parent's d_subdirs */
- spin_lock(&dcache_lock);
spin_lock(&parent->d_lock);
spin_lock_nested(&dn->d_lock, DENTRY_D_LOCK_NESTED);
list_move(&dn->d_u.d_child, &parent->d_subdirs);
spin_unlock(&dn->d_lock);
spin_unlock(&parent->d_lock);
- spin_unlock(&dcache_lock);
}
di = dn->d_fsdata;
Index: linux-2.6/Documentation/filesystems/dentry-locking.txt
===================================================================
--- linux-2.6.orig/Documentation/filesystems/dentry-locking.txt 2010-11-17 00:50:48.000000000 +1100
+++ linux-2.6/Documentation/filesystems/dentry-locking.txt 2010-11-17 00:52:37.000000000 +1100
@@ -31,6 +31,7 @@ significant change is the way d_lookup t
doesn't acquire the dcache_lock for this and rely on RCU to ensure
that the dentry has not been *freed*.
+dcache_lock no longer exists, dentry locking is explained in fs/dcache.c
Dcache locking details
======================
@@ -50,14 +51,12 @@ Safe lock-free look-up of dcache hash ta
Dcache is a complex data structure with the hash table entries also
linked together in other lists. In 2.4 kernel, dcache_lock protected
-all the lists. We applied RCU only on hash chain walking. The rest of
-the lists are still protected by dcache_lock. Some of the important
-changes are :
+all the lists. RCU dentry hash walking works like this:
1. The deletion from hash chain is done using hlist_del_rcu() macro
which doesn't initialize next pointer of the deleted dentry and
this allows us to walk safely lock-free while a deletion is
- happening.
+ happening. This is a standard hlist_rcu iteration.
2. Insertion of a dentry into the hash table is done using
hlist_add_head_rcu() which take care of ordering the writes - the
@@ -66,19 +65,18 @@ the lists are still protected by dcache_
which has since been replaced by hlist_for_each_entry_rcu(), while
walking the hash chain. The only requirement is that all
initialization to the dentry must be done before
- hlist_add_head_rcu() since we don't have dcache_lock protection
- while traversing the hash chain. This isn't different from the
- existing code.
-
-3. The dentry looked up without holding dcache_lock by cannot be
- returned for walking if it is unhashed. It then may have a NULL
- d_inode or other bogosity since RCU doesn't protect the other
- fields in the dentry. We therefore use a flag DCACHE_UNHASHED to
- indicate unhashed dentries and use this in conjunction with a
- per-dentry lock (d_lock). Once looked up without the dcache_lock,
- we acquire the per-dentry lock (d_lock) and check if the dentry is
- unhashed. If so, the look-up is failed. If not, the reference count
- of the dentry is increased and the dentry is returned.
+ hlist_add_head_rcu() since we don't have lock protection
+ while traversing the hash chain.
+
+3. The dentry looked up without holding locks cannot be returned for
+ walking if it is unhashed. It then may have a NULL d_inode or other
+ bogosity since RCU doesn't protect the other fields in the dentry. We
+ therefore use a flag DCACHE_UNHASHED to indicate unhashed dentries
+ and use this in conjunction with a per-dentry lock (d_lock). Once
+ looked up without locks, we acquire the per-dentry lock (d_lock) and
+ check if the dentry is unhashed. If so, the look-up is failed. If not,
+ the reference count of the dentry is increased and the dentry is
+ returned.
4. Once a dentry is looked up, it must be ensured during the path walk
for that component it doesn't go away. In pre-2.5.10 code, this was
@@ -86,10 +84,10 @@ the lists are still protected by dcache_
In some sense, dcache_rcu path walking looks like the pre-2.5.10
version.
-5. All dentry hash chain updates must take the dcache_lock as well as
- the per-dentry lock in that order. dput() does this to ensure that
- a dentry that has just been looked up in another CPU doesn't get
- deleted before dget() can be done on it.
+5. All dentry hash chain updates must take the per-dentry lock (see
+ fs/dcache.c). This excludes dput() to ensure that a dentry that has
+ been looked up concurrently does not get deleted before dget() can
+ take a ref.
6. There are several ways to do reference counting of RCU protected
objects. One such example is in ipv4 route cache where deferred
Index: linux-2.6/Documentation/filesystems/porting
===================================================================
--- linux-2.6.orig/Documentation/filesystems/porting 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/Documentation/filesystems/porting 2010-11-17 00:52:37.000000000 +1100
@@ -216,7 +216,6 @@ had ->revalidate()) add calls in ->follo
->d_parent changes are not protected by BKL anymore. Read access is safe
if at least one of the following is true:
* filesystem has no cross-directory rename()
- * dcache_lock is held
* we know that parent had been locked (e.g. we are looking at
->d_parent of ->lookup() argument).
* we are called from ->rename().
@@ -341,3 +340,10 @@ look at examples of other filesystems) f
changed. Read updated documentation in Documentation/filesystems/vfs.txt (and
look at examples of other filesystems) for guidance.
+---
+[mandatory]
+ dcache_lock is gone, replaced by fine grained locks. See fs/dcache.c
+for details of what locks to replace dcache_lock with in order to protect
+particular things. Most of the time, a filesystem only needs ->d_lock, which
+protects *all* the dcache state of a given dentry.
+
Index: linux-2.6/include/linux/namei.h
===================================================================
--- linux-2.6.orig/include/linux/namei.h 2010-11-17 00:50:47.000000000 +1100
+++ linux-2.6/include/linux/namei.h 2010-11-17 00:52:37.000000000 +1100
@@ -41,7 +41,6 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LA
* - require a directory
* - ending slashes ok even for nonexistent files
* - internal "there are more path components" flag
- * - locked when lookup done with dcache_lock held
* - dentry cache is untrusted; force a real lookup
*/
#define LOOKUP_FOLLOW 1
Index: linux-2.6/mm/filemap.c
===================================================================
--- linux-2.6.orig/mm/filemap.c 2010-11-17 00:50:48.000000000 +1100
+++ linux-2.6/mm/filemap.c 2010-11-17 00:52:37.000000000 +1100
@@ -102,9 +102,6 @@
* ->inode_lock (zap_pte_range->set_page_dirty)
* ->private_lock (zap_pte_range->__set_page_dirty_buffers)
*
- * ->task->proc_lock
- * ->dcache_lock (proc_pid_lookup)
- *
* (code doesn't rely on that order, so you could switch it around)
* ->tasklist_lock (memory_failure, collect_procs_ao)
* ->i_mmap_lock
Index: linux-2.6/fs/9p/vfs_inode.c
===================================================================
--- linux-2.6.orig/fs/9p/vfs_inode.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/9p/vfs_inode.c 2010-11-17 00:52:37.000000000 +1100
@@ -270,13 +270,11 @@ static struct dentry *v9fs_dentry_from_d
{
struct dentry *dentry;
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
/* Directory should have only one entry. */
BUG_ON(S_ISDIR(inode->i_mode) && !list_is_singular(&inode->i_dentry));
dentry = list_entry(inode->i_dentry.next, struct dentry, d_alias);
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
return dentry;
}
Index: linux-2.6/fs/cifs/inode.c
===================================================================
--- linux-2.6.orig/fs/cifs/inode.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/cifs/inode.c 2010-11-17 00:52:37.000000000 +1100
@@ -804,17 +804,14 @@ inode_has_hashed_dentries(struct inode *
{
struct dentry *dentry;
- spin_lock(&dcache_lock);
spin_lock(&dcache_inode_lock);
list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
if (!d_unhashed(dentry) || IS_ROOT(dentry)) {
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
return true;
}
}
spin_unlock(&dcache_inode_lock);
- spin_unlock(&dcache_lock);
return false;
}
Index: linux-2.6/drivers/staging/smbfs/cache.c
===================================================================
--- linux-2.6.orig/drivers/staging/smbfs/cache.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/drivers/staging/smbfs/cache.c 2010-11-17 01:05:39.000000000 +1100
@@ -62,7 +62,6 @@ smb_invalidate_dircache_entries(struct d
struct list_head *next;
struct dentry *dentry;
- spin_lock(&dcache_lock);
spin_lock(&parent->d_lock);
next = parent->d_subdirs.next;
while (next != &parent->d_subdirs) {
@@ -72,7 +71,6 @@ smb_invalidate_dircache_entries(struct d
next = next->next;
}
spin_unlock(&parent->d_lock);
- spin_unlock(&dcache_lock);
}
/*
@@ -98,7 +96,6 @@ smb_dget_fpos(struct dentry *dentry, str
}
/* If a pointer is invalid, we search the dentry. */
- spin_lock(&dcache_lock);
spin_lock(&parent->d_lock);
next = parent->d_subdirs.next;
while (next != &parent->d_subdirs) {
@@ -115,7 +112,6 @@ smb_dget_fpos(struct dentry *dentry, str
dent = NULL;
out_unlock:
spin_unlock(&parent->d_lock);
- spin_unlock(&dcache_lock);
return dent;
}
Index: linux-2.6/fs/libfs.c
===================================================================
--- linux-2.6.orig/fs/libfs.c 2010-11-17 00:52:37.000000000 +1100
+++ linux-2.6/fs/libfs.c 2010-11-17 00:52:37.000000000 +1100
@@ -100,7 +100,6 @@ loff_t dcache_dir_lseek(struct file *fil
struct dentry *cursor = file->private_data;
loff_t n = file->f_pos - 2;
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
/* d_lock not required for cursor */
list_del(&cursor->d_u.d_child);
@@ -116,7 +115,6 @@ loff_t dcache_dir_lseek(struct file *fil
}
list_add_tail(&cursor->d_u.d_child, p);
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
}
}
mutex_unlock(&dentry->d_inode->i_mutex);
@@ -159,7 +157,6 @@ int dcache_readdir(struct file * filp, v
i++;
/* fallthrough */
default:
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
if (filp->f_pos == 2)
list_move(q, &dentry->d_subdirs);
@@ -175,13 +172,11 @@ int dcache_readdir(struct file * filp, v
spin_unlock(&next->d_lock);
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
if (filldir(dirent, next->d_name.name,
next->d_name.len, filp->f_pos,
next->d_inode->i_ino,
dt_type(next->d_inode)) < 0)
return 0;
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
/* next is still alive */
@@ -191,7 +186,6 @@ int dcache_readdir(struct file * filp, v
filp->f_pos++;
}
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
}
return 0;
}
@@ -285,7 +279,6 @@ int simple_empty(struct dentry *dentry)
struct dentry *child;
int ret = 0;
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) {
spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
@@ -298,7 +291,6 @@ int simple_empty(struct dentry *dentry)
ret = 1;
out:
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
return ret;
}
Index: linux-2.6/include/linux/fsnotify.h
===================================================================
--- linux-2.6.orig/include/linux/fsnotify.h 2010-11-17 00:50:48.000000000 +1100
+++ linux-2.6/include/linux/fsnotify.h 2010-11-17 00:52:37.000000000 +1100
@@ -17,7 +17,6 @@
/*
* fsnotify_d_instantiate - instantiate a dentry for inode
- * Called with dcache_lock held.
*/
static inline void fsnotify_d_instantiate(struct dentry *dentry,
struct inode *inode)
@@ -62,7 +61,6 @@ static inline int fsnotify_perm(struct f
/*
* fsnotify_d_move - dentry has been moved
- * Called with dcache_lock and dentry->d_lock held.
*/
static inline void fsnotify_d_move(struct dentry *dentry)
{
--
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