if (retval)
return retval;
- return security_inode_permission(inode,
- mask & (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND));
+ return security_inode_permission(inode, mask);
}
/**
static __always_inline void set_root(struct nameidata *nd)
{
- if (!nd->root.mnt) {
- struct fs_struct *fs = current->fs;
- read_lock(&fs->lock);
- nd->root = fs->root;
- path_get(&nd->root);
- read_unlock(&fs->lock);
- }
+ if (!nd->root.mnt)
+ get_fs_root(current->fs, &nd->root);
}
static int link_path_walk(const char *, struct nameidata *);
{
struct vfsmount *parent;
struct dentry *mountpoint;
- spin_lock(&vfsmount_lock);
+
+ br_read_lock(vfsmount_lock);
parent = path->mnt->mnt_parent;
if (parent == path->mnt) {
- spin_unlock(&vfsmount_lock);
+ br_read_unlock(vfsmount_lock);
return 0;
}
mntget(parent);
mountpoint = dget(path->mnt->mnt_mountpoint);
- spin_unlock(&vfsmount_lock);
+ br_read_unlock(vfsmount_lock);
dput(path->dentry);
path->dentry = mountpoint;
mntput(path->mnt);
follow_mount(&nd->path);
}
+/*
+ * Allocate a dentry with name and parent, and perform a parent
+ * directory ->lookup on it. Returns the new dentry, or ERR_PTR
+ * on error. parent->d_inode->i_mutex must be held. d_lookup must
+ * have verified that no child exists while under i_mutex.
+ */
+static struct dentry *d_alloc_and_lookup(struct dentry *parent,
+ struct qstr *name, struct nameidata *nd)
+{
+ struct inode *inode = parent->d_inode;
+ struct dentry *dentry;
+ struct dentry *old;
+
+ /* Don't create child dentry for a dead directory. */
+ if (unlikely(IS_DEADDIR(inode)))
+ return ERR_PTR(-ENOENT);
+
+ dentry = d_alloc(parent, name);
+ if (unlikely(!dentry))
+ return ERR_PTR(-ENOMEM);
+
+ old = inode->i_op->lookup(inode, dentry, nd);
+ if (unlikely(old)) {
+ dput(dentry);
+ dentry = old;
+ }
+ return dentry;
+}
+
/*
* It's more convoluted than I'd like it to be, but... it's still fairly
* small and for now I'd prefer to have fast path as straight as possible.
return err;
}
+ /*
+ * Rename seqlock is not required here because in the off chance
+ * of a false negative due to a concurrent rename, we're going to
+ * do the non-racy lookup, below.
+ */
dentry = __d_lookup(nd->path.dentry, name);
if (!dentry)
goto need_lookup;
+found:
if (dentry->d_op && dentry->d_op->d_revalidate)
goto need_revalidate;
done:
mutex_lock(&dir->i_mutex);
/*
* First re-do the cached lookup just in case it was created
- * while we waited for the directory semaphore..
+ * while we waited for the directory semaphore, or the first
+ * lookup failed due to an unrelated rename.
*
- * FIXME! This could use version numbering or similar to
- * avoid unnecessary cache lookups.
- *
- * The "dcache_lock" is purely to protect the RCU list walker
- * from concurrent renames at this point (we mustn't get false
- * negatives from the RCU list walk here, unlike the optimistic
- * fast walk).
- *
- * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup
+ * This could use version numbering or similar to avoid unnecessary
+ * cache lookups, but then we'd have to do the first lookup in the
+ * non-racy way. However in the common case here, everything should
+ * be hot in cache, so would it be a big win?
*/
dentry = d_lookup(parent, name);
- if (!dentry) {
- struct dentry *new;
-
- /* Don't create child dentry for a dead directory. */
- dentry = ERR_PTR(-ENOENT);
- if (IS_DEADDIR(dir))
- goto out_unlock;
-
- new = d_alloc(parent, name);
- dentry = ERR_PTR(-ENOMEM);
- if (new) {
- dentry = dir->i_op->lookup(dir, new, nd);
- if (dentry)
- dput(new);
- else
- dentry = new;
- }
-out_unlock:
+ if (likely(!dentry)) {
+ dentry = d_alloc_and_lookup(parent, name, nd);
mutex_unlock(&dir->i_mutex);
if (IS_ERR(dentry))
goto fail;
goto done;
}
-
/*
* Uhhuh! Nasty case: the cache was re-populated while
* we waited on the semaphore. Need to revalidate.
*/
mutex_unlock(&dir->i_mutex);
- if (dentry->d_op && dentry->d_op->d_revalidate) {
- dentry = do_revalidate(dentry, nd);
- if (!dentry)
- dentry = ERR_PTR(-ENOENT);
- }
- if (IS_ERR(dentry))
- goto fail;
- goto done;
+ goto found;
need_revalidate:
dentry = do_revalidate(dentry, nd);
nd->path = nd->root;
path_get(&nd->root);
} else if (dfd == AT_FDCWD) {
- struct fs_struct *fs = current->fs;
- read_lock(&fs->lock);
- nd->path = fs->pwd;
- path_get(&fs->pwd);
- read_unlock(&fs->lock);
+ get_fs_pwd(current->fs, &nd->path);
} else {
struct dentry *dentry;
static struct dentry *__lookup_hash(struct qstr *name,
struct dentry *base, struct nameidata *nd)
{
+ struct inode *inode = base->d_inode;
struct dentry *dentry;
- struct inode *inode;
int err;
- inode = base->d_inode;
+ err = exec_permission(inode);
+ if (err)
+ return ERR_PTR(err);
/*
* See if the low-level filesystem might want
goto out;
}
- dentry = __d_lookup(base, name);
-
- /* lockess __d_lookup may fail due to concurrent d_move()
- * in some unrelated directory, so try with d_lookup
+ /*
+ * Don't bother with __d_lookup: callers are for creat as
+ * well as unlink, so a lot of the time it would cost
+ * a double lookup.
*/
- if (!dentry)
- dentry = d_lookup(base, name);
+ dentry = d_lookup(base, name);
if (dentry && dentry->d_op && dentry->d_op->d_revalidate)
dentry = do_revalidate(dentry, nd);
- if (!dentry) {
- struct dentry *new;
-
- /* Don't create child dentry for a dead directory. */
- dentry = ERR_PTR(-ENOENT);
- if (IS_DEADDIR(inode))
- goto out;
-
- new = d_alloc(base, name);
- dentry = ERR_PTR(-ENOMEM);
- if (!new)
- goto out;
- dentry = inode->i_op->lookup(inode, new, nd);
- if (!dentry)
- dentry = new;
- else
- dput(new);
- }
+ if (!dentry)
+ dentry = d_alloc_and_lookup(base, name, nd);
out:
return dentry;
}
*/
static struct dentry *lookup_hash(struct nameidata *nd)
{
- int err;
-
- err = exec_permission(nd->path.dentry->d_inode);
- if (err)
- return ERR_PTR(err);
return __lookup_hash(&nd->last, nd->path.dentry, nd);
}
if (err)
return ERR_PTR(err);
- err = exec_permission(base->d_inode);
- if (err)
- return ERR_PTR(err);
return __lookup_hash(&this, base, NULL);
}
*/
error = locks_verify_locked(inode);
if (!error)
- error = security_path_truncate(path, 0,
- ATTR_MTIME|ATTR_CTIME|ATTR_OPEN);
+ error = security_path_truncate(path);
if (!error) {
error = do_truncate(path->dentry, 0,
ATTR_MTIME|ATTR_CTIME|ATTR_OPEN,
*/
if (will_truncate)
mnt_drop_write(nd->path.mnt);
+ path_put(&nd->path);
return filp;
exit:
}
filp = nameidata_to_filp(nd);
mnt_drop_write(nd->path.mnt);
+ path_put(&nd->path);
if (!IS_ERR(filp)) {
error = ima_file_check(filp, acc_mode);
if (error) {
goto slashes;
inode = dentry->d_inode;
if (inode)
- atomic_inc(&inode->i_count);
+ ihold(inode);
error = mnt_want_write(nd.path.mnt);
if (error)
goto exit2;
{
int error;
int is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
- const char *old_name;
+ const unsigned char *old_name;
if (old_dentry->d_inode == new_dentry->d_inode)
return 0;
git://bbs.cooldavid.org / net-next-2.6.git / blobdiff