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Merge branch 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs namei updates from Al Viro: - make lookup_one_len() safe with parent locked only shared(incoming afs series wants that) - fix of getname_kernel() regression from 2015 (-stable fodder, that one). * 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: getname_kernel() needs to make sure that ->name != ->iname in long case make lookup_one_len() safe to use with directory locked shared new helper: __lookup_slow() merge common parts of lookup_one_len{,_unlocked} into common helper
This commit is contained in:
commit
fd3b36d275
1 changed files with 57 additions and 67 deletions
124
fs/namei.c
124
fs/namei.c
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@ -224,9 +224,10 @@ getname_kernel(const char * filename)
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if (len <= EMBEDDED_NAME_MAX) {
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if (len <= EMBEDDED_NAME_MAX) {
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result->name = (char *)result->iname;
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result->name = (char *)result->iname;
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} else if (len <= PATH_MAX) {
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} else if (len <= PATH_MAX) {
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const size_t size = offsetof(struct filename, iname[1]);
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struct filename *tmp;
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struct filename *tmp;
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tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
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tmp = kmalloc(size, GFP_KERNEL);
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if (unlikely(!tmp)) {
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if (unlikely(!tmp)) {
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__putname(result);
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__putname(result);
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return ERR_PTR(-ENOMEM);
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return ERR_PTR(-ENOMEM);
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@ -1597,22 +1598,21 @@ static int lookup_fast(struct nameidata *nd,
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}
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}
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/* Fast lookup failed, do it the slow way */
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/* Fast lookup failed, do it the slow way */
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static struct dentry *lookup_slow(const struct qstr *name,
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static struct dentry *__lookup_slow(const struct qstr *name,
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struct dentry *dir,
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struct dentry *dir,
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unsigned int flags)
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unsigned int flags)
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{
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{
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struct dentry *dentry = ERR_PTR(-ENOENT), *old;
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struct dentry *dentry, *old;
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struct inode *inode = dir->d_inode;
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struct inode *inode = dir->d_inode;
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DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
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DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
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inode_lock_shared(inode);
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/* Don't go there if it's already dead */
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/* Don't go there if it's already dead */
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if (unlikely(IS_DEADDIR(inode)))
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if (unlikely(IS_DEADDIR(inode)))
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goto out;
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return ERR_PTR(-ENOENT);
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again:
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again:
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dentry = d_alloc_parallel(dir, name, &wq);
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dentry = d_alloc_parallel(dir, name, &wq);
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if (IS_ERR(dentry))
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if (IS_ERR(dentry))
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goto out;
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return dentry;
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if (unlikely(!d_in_lookup(dentry))) {
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if (unlikely(!d_in_lookup(dentry))) {
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if (!(flags & LOOKUP_NO_REVAL)) {
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if (!(flags & LOOKUP_NO_REVAL)) {
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int error = d_revalidate(dentry, flags);
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int error = d_revalidate(dentry, flags);
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@ -1634,11 +1634,21 @@ again:
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dentry = old;
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dentry = old;
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}
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}
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}
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}
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out:
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inode_unlock_shared(inode);
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return dentry;
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return dentry;
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}
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}
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static struct dentry *lookup_slow(const struct qstr *name,
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struct dentry *dir,
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unsigned int flags)
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{
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struct inode *inode = dir->d_inode;
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struct dentry *res;
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inode_lock_shared(inode);
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res = __lookup_slow(name, dir, flags);
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inode_unlock_shared(inode);
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return res;
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}
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static inline int may_lookup(struct nameidata *nd)
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static inline int may_lookup(struct nameidata *nd)
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{
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{
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if (nd->flags & LOOKUP_RCU) {
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if (nd->flags & LOOKUP_RCU) {
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@ -2421,6 +2431,38 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
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}
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}
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EXPORT_SYMBOL(vfs_path_lookup);
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EXPORT_SYMBOL(vfs_path_lookup);
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static int lookup_one_len_common(const char *name, struct dentry *base,
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int len, struct qstr *this)
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{
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this->name = name;
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this->len = len;
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this->hash = full_name_hash(base, name, len);
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if (!len)
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return -EACCES;
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if (unlikely(name[0] == '.')) {
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if (len < 2 || (len == 2 && name[1] == '.'))
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return -EACCES;
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}
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while (len--) {
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unsigned int c = *(const unsigned char *)name++;
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if (c == '/' || c == '\0')
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return -EACCES;
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}
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/*
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* See if the low-level filesystem might want
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* to use its own hash..
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*/
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if (base->d_flags & DCACHE_OP_HASH) {
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int err = base->d_op->d_hash(base, this);
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if (err < 0)
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return err;
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}
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return inode_permission(base->d_inode, MAY_EXEC);
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}
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/**
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/**
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* lookup_one_len - filesystem helper to lookup single pathname component
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* lookup_one_len - filesystem helper to lookup single pathname component
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* @name: pathname component to lookup
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* @name: pathname component to lookup
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@ -2434,43 +2476,18 @@ EXPORT_SYMBOL(vfs_path_lookup);
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*/
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*/
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struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
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struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
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{
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{
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struct dentry *dentry;
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struct qstr this;
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struct qstr this;
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unsigned int c;
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int err;
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int err;
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WARN_ON_ONCE(!inode_is_locked(base->d_inode));
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WARN_ON_ONCE(!inode_is_locked(base->d_inode));
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this.name = name;
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err = lookup_one_len_common(name, base, len, &this);
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this.len = len;
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this.hash = full_name_hash(base, name, len);
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if (!len)
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return ERR_PTR(-EACCES);
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if (unlikely(name[0] == '.')) {
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if (len < 2 || (len == 2 && name[1] == '.'))
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return ERR_PTR(-EACCES);
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}
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while (len--) {
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c = *(const unsigned char *)name++;
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if (c == '/' || c == '\0')
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return ERR_PTR(-EACCES);
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}
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/*
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* See if the low-level filesystem might want
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* to use its own hash..
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*/
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if (base->d_flags & DCACHE_OP_HASH) {
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int err = base->d_op->d_hash(base, &this);
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if (err < 0)
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return ERR_PTR(err);
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}
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err = inode_permission(base->d_inode, MAY_EXEC);
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if (err)
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if (err)
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return ERR_PTR(err);
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return ERR_PTR(err);
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return __lookup_hash(&this, base, 0);
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dentry = lookup_dcache(&this, base, 0);
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return dentry ? dentry : __lookup_slow(&this, base, 0);
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}
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}
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EXPORT_SYMBOL(lookup_one_len);
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EXPORT_SYMBOL(lookup_one_len);
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@ -2490,37 +2507,10 @@ struct dentry *lookup_one_len_unlocked(const char *name,
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struct dentry *base, int len)
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struct dentry *base, int len)
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{
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{
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struct qstr this;
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struct qstr this;
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unsigned int c;
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int err;
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int err;
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struct dentry *ret;
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struct dentry *ret;
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this.name = name;
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err = lookup_one_len_common(name, base, len, &this);
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this.len = len;
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this.hash = full_name_hash(base, name, len);
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if (!len)
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return ERR_PTR(-EACCES);
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if (unlikely(name[0] == '.')) {
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if (len < 2 || (len == 2 && name[1] == '.'))
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return ERR_PTR(-EACCES);
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}
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while (len--) {
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c = *(const unsigned char *)name++;
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if (c == '/' || c == '\0')
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return ERR_PTR(-EACCES);
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}
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/*
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* See if the low-level filesystem might want
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* to use its own hash..
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*/
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if (base->d_flags & DCACHE_OP_HASH) {
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int err = base->d_op->d_hash(base, &this);
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if (err < 0)
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return ERR_PTR(err);
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}
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err = inode_permission(base->d_inode, MAY_EXEC);
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if (err)
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if (err)
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return ERR_PTR(err);
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return ERR_PTR(err);
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