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authorNick Piggin <npiggin@kernel.dk>2011-01-07 17:49:33 +1100
committerNick Piggin <npiggin@kernel.dk>2011-01-07 17:50:21 +1100
commitda5029563a0a026c64821b09e8e7b4fd81d3fe1b (patch)
tree5d5618e0cb382390073377b1be7d0aa76879ac54 /fs/libfs.c
parentb7ab39f631f505edc2bbdb86620d5493f995c9da (diff)
downloadlinux-da5029563a0a026c64821b09e8e7b4fd81d3fe1b.tar.bz2
fs: dcache scale d_unhashed
Protect d_unhashed(dentry) condition with d_lock. This means keeping DCACHE_UNHASHED bit in synch with hash manipulations. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Diffstat (limited to 'fs/libfs.c')
-rw-r--r--fs/libfs.c29
1 files changed, 20 insertions, 9 deletions
diff --git a/fs/libfs.c b/fs/libfs.c
index b9d25d83e228..433e7139c23a 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -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);