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fs: dcache scale d_unhashed

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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>
This commit is contained in:
Nick Piggin 2011-01-07 17:49:33 +11:00
parent b7ab39f631
commit da5029563a
10 changed files with 102 additions and 54 deletions
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3
arch/powerpc/platforms/cell/spufs/inode.c
View File

@ -166,6 +166,9 @@ static void spufs_prune_dir(struct dentry *dir)
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
simple_unlink(dir->d_inode, dentry);
/* XXX: what is dcache_lock protecting here? Other
* filesystems (IB, configfs) release dcache_lock
* before unlink */
spin_unlock(&dcache_lock);
dput(dentry);
} else {

3
drivers/usb/core/inode.c
View File

@ -347,10 +347,13 @@ static int usbfs_empty (struct dentry *dentry)
list_for_each(list, &dentry->d_subdirs) {
struct dentry *de = list_entry(list, struct dentry, d_u.d_child);
spin_lock(&de->d_lock);
if (usbfs_positive(de)) {
spin_unlock(&de->d_lock);
spin_unlock(&dcache_lock);
return 0;
}
spin_unlock(&de->d_lock);
}
spin_unlock(&dcache_lock);

13
fs/autofs4/autofs_i.h
View File

@ -254,19 +254,6 @@ static inline int simple_positive(struct dentry *dentry)
return dentry->d_inode && !d_unhashed(dentry);
}
static inline int __simple_empty(struct dentry *dentry)
{
struct dentry *child;
int ret = 0;
list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child)
if (simple_positive(child))
goto out;
ret = 1;
out:
return ret;
}
static inline void autofs4_add_expiring(struct dentry *dentry)
{
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);

21
fs/autofs4/expire.c
View File

@ -160,14 +160,18 @@ static int autofs4_tree_busy(struct vfsmount *mnt,
spin_lock(&dcache_lock);
for (p = top; p; p = next_dentry(p, top)) {
spin_lock(&p->d_lock);
/* Negative dentry - give up */
if (!simple_positive(p))
if (!simple_positive(p)) {
spin_unlock(&p->d_lock);
continue;
}
DPRINTK("dentry %p %.*s",
p, (int) p->d_name.len, p->d_name.name);
p = dget(p);
p = dget_dlock(p);
spin_unlock(&p->d_lock);
spin_unlock(&dcache_lock);
/*
@ -228,14 +232,18 @@ static struct dentry *autofs4_check_leaves(struct vfsmount *mnt,
spin_lock(&dcache_lock);
for (p = parent; p; p = next_dentry(p, parent)) {
spin_lock(&p->d_lock);
/* Negative dentry - give up */
if (!simple_positive(p))
if (!simple_positive(p)) {
spin_unlock(&p->d_lock);
continue;
}
DPRINTK("dentry %p %.*s",
p, (int) p->d_name.len, p->d_name.name);
p = dget(p);
p = dget_dlock(p);
spin_unlock(&p->d_lock);
spin_unlock(&dcache_lock);
if (d_mountpoint(p)) {
@ -324,12 +332,15 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
/* Negative dentry - give up */
spin_lock(&dentry->d_lock);
if (!simple_positive(dentry)) {
next = next->next;
spin_unlock(&dentry->d_lock);
continue;
}
dentry = dget(dentry);
dentry = dget_dlock(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
spin_lock(&sbi->fs_lock);

5
fs/ceph/dir.c
View File

@ -136,6 +136,7 @@ more:
fi->at_end = 1;
goto out_unlock;
}
spin_lock(&dentry->d_lock);
if (!d_unhashed(dentry) && dentry->d_inode &&
ceph_snap(dentry->d_inode) != CEPH_SNAPDIR &&
ceph_ino(dentry->d_inode) != CEPH_INO_CEPH &&
@ -145,13 +146,13 @@ more:
dentry->d_name.len, dentry->d_name.name, di->offset,
filp->f_pos, d_unhashed(dentry) ? " unhashed" : "",
!dentry->d_inode ? " null" : "");
spin_unlock(&dentry->d_lock);
p = p->prev;
dentry = list_entry(p, struct dentry, d_u.d_child);
di = ceph_dentry(dentry);
}
spin_lock(&dentry->d_lock);
dentry->d_count++;
dget_dlock(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);

2
fs/configfs/configfs_internal.h
View File

@ -121,6 +121,7 @@ static inline struct config_item *configfs_get_config_item(struct dentry *dentry
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;
if (sd->s_type & CONFIGFS_ITEM_LINK) {
@ -129,6 +130,7 @@ static inline struct config_item *configfs_get_config_item(struct dentry *dentry
} else
item = config_item_get(sd->s_element);
}
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
return item;

74
fs/dcache.c
View File

@ -46,6 +46,7 @@
* - d_name
* - d_lru
* - d_count
* - d_unhashed()
*
* Ordering:
* dcache_lock
@ -53,6 +54,13 @@
* dcache_lru_lock
* dcache_hash_lock
*
* If there is an ancestor relationship:
* dentry->d_parent->...->d_parent->d_lock
* ...
* dentry->d_parent->d_lock
* dentry->d_lock
*
* If no ancestor relationship:
* if (dentry1 < dentry2)
* dentry1->d_lock
* dentry2->d_lock
@ -379,7 +387,9 @@ 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;
}
@ -388,9 +398,11 @@ int d_invalidate(struct dentry * dentry)
* to get rid of unused child entries.
*/
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);
}
/*
@ -403,7 +415,6 @@ int d_invalidate(struct dentry * dentry)
* we might still populate it if it was a
* working directory or similar).
*/
spin_lock(&dentry->d_lock);
if (dentry->d_count > 1) {
if (dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode)) {
spin_unlock(&dentry->d_lock);
@ -490,35 +501,44 @@ EXPORT_SYMBOL(dget_parent);
* any other hashed alias over that one unless @want_discon is set,
* in which case only return an IS_ROOT, DCACHE_DISCONNECTED alias.
*/
static struct dentry * __d_find_alias(struct inode *inode, int want_discon)
static struct dentry *__d_find_alias(struct inode *inode, int want_discon)
{
struct list_head *head, *next, *tmp;
struct dentry *alias, *discon_alias=NULL;
struct dentry *alias, *discon_alias;
head = &inode->i_dentry;
next = inode->i_dentry.next;
while (next != head) {
tmp = next;
next = tmp->next;
prefetch(next);
alias = list_entry(tmp, struct dentry, d_alias);
again:
discon_alias = NULL;
list_for_each_entry(alias, &inode->i_dentry, d_alias) {
spin_lock(&alias->d_lock);
if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
if (IS_ROOT(alias) &&
(alias->d_flags & DCACHE_DISCONNECTED))
(alias->d_flags & DCACHE_DISCONNECTED)) {
discon_alias = alias;
else if (!want_discon) {
__dget_locked(alias);
} else if (!want_discon) {
__dget_locked_dlock(alias);
spin_unlock(&alias->d_lock);
return alias;
}
}
spin_unlock(&alias->d_lock);
}
if (discon_alias)
__dget_locked(discon_alias);
return discon_alias;
if (discon_alias) {
alias = discon_alias;
spin_lock(&alias->d_lock);
if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
if (IS_ROOT(alias) &&
(alias->d_flags & DCACHE_DISCONNECTED)) {
__dget_locked_dlock(alias);
spin_unlock(&alias->d_lock);
return alias;
}
}
spin_unlock(&alias->d_lock);
goto again;
}
return NULL;
}
struct dentry * d_find_alias(struct inode *inode)
struct dentry *d_find_alias(struct inode *inode)
{
struct dentry *de = NULL;
@ -801,8 +821,8 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry)
spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
dentry_lru_del(dentry);
spin_unlock(&dentry->d_lock);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
for (;;) {
@ -817,8 +837,8 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry)
d_u.d_child) {
spin_lock(&loop->d_lock);
dentry_lru_del(loop);
spin_unlock(&loop->d_lock);
__d_drop(loop);
spin_unlock(&loop->d_lock);
cond_resched_lock(&dcache_lock);
}
spin_unlock(&dcache_lock);
@ -1863,7 +1883,10 @@ static void d_move_locked(struct dentry * dentry, struct dentry * target)
/*
* XXXX: do we really need to take target->d_lock?
*/
if (target < dentry) {
if (d_ancestor(dentry, target)) {
spin_lock(&dentry->d_lock);
spin_lock_nested(&target->d_lock, DENTRY_D_LOCK_NESTED);
} else if (d_ancestor(target, dentry) || target < dentry) {
spin_lock(&target->d_lock);
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
} else {
@ -2542,13 +2565,16 @@ resume:
struct list_head *tmp = next;
struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
next = tmp->next;
if (d_unhashed(dentry)||!dentry->d_inode)
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
if (d_unhashed(dentry) || !dentry->d_inode) {
spin_unlock(&dentry->d_lock);
continue;
}
if (!list_empty(&dentry->d_subdirs)) {
spin_unlock(&dentry->d_lock);
this_parent = dentry;
goto repeat;
}
spin_lock(&dentry->d_lock);
dentry->d_count--;
spin_unlock(&dentry->d_lock);
}

29
fs/libfs.c
View File

@ -16,6 +16,11 @@
#include <asm/uaccess.h>
static inline int simple_positive(struct dentry *dentry)
{
return dentry->d_inode && !d_unhashed(dentry);
}
int simple_getattr(struct vfsmount *mnt, struct dentry *dentry,
struct kstat *stat)
{
@ -100,8 +105,10 @@ loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin)
while (n && p != &file->f_path.dentry->d_subdirs) {
struct dentry *next;
next = list_entry(p, struct dentry, d_u.d_child);
if (!d_unhashed(next) && next->d_inode)
spin_lock(&next->d_lock);
if (simple_positive(next))
n--;
spin_unlock(&next->d_lock);
p = p->next;
}
list_add_tail(&cursor->d_u.d_child, p);
@ -155,9 +162,13 @@ int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
for (p=q->next; p != &dentry->d_subdirs; p=p->next) {
struct dentry *next;
next = list_entry(p, struct dentry, d_u.d_child);
if (d_unhashed(next) || !next->d_inode)
spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
if (!simple_positive(next)) {
spin_unlock(&next->d_lock);
continue;
}
spin_unlock(&next->d_lock);
spin_unlock(&dcache_lock);
if (filldir(dirent, next->d_name.name,
next->d_name.len, filp->f_pos,
@ -259,20 +270,20 @@ int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *den
return 0;
}
static inline int simple_positive(struct dentry *dentry)
{
return dentry->d_inode && !d_unhashed(dentry);
}
int simple_empty(struct dentry *dentry)
{
struct dentry *child;
int ret = 0;
spin_lock(&dcache_lock);
list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child)
if (simple_positive(child))
list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) {
spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
if (simple_positive(child)) {
spin_unlock(&child->d_lock);
goto out;
}
spin_unlock(&child->d_lock);
}
ret = 1;
out:
spin_unlock(&dcache_lock);

5
fs/ocfs2/dcache.c
View File

@ -174,13 +174,16 @@ struct dentry *ocfs2_find_local_alias(struct inode *inode,
list_for_each(p, &inode->i_dentry) {
dentry = list_entry(p, struct dentry, d_alias);
spin_lock(&dentry->d_lock);
if (ocfs2_match_dentry(dentry, parent_blkno, skip_unhashed)) {
mlog(0, "dentry found: %.*s\n",
dentry->d_name.len, dentry->d_name.name);
dget_locked(dentry);
dget_locked_dlock(dentry);
spin_unlock(&dentry->d_lock);
break;
}
spin_unlock(&dentry->d_lock);
dentry = NULL;
}

1
security/tomoyo/realpath.c
View File

@ -14,6 +14,7 @@
#include <linux/slab.h>
#include <net/sock.h>
#include "common.h"
#include "../../fs/internal.h"
/**
* tomoyo_encode: Convert binary string to ascii string.