VFS: Put a small type field into struct dentry::d_flags
Put a type field into struct dentry::d_flags to indicate if the dentry is one of the following types that relate particularly to pathwalk: Miss (negative dentry) Directory "Automount" directory (defective - no i_op->lookup()) Symlink Other (regular, socket, fifo, device) The type field is set to one of the first five types on a dentry by calls to __d_instantiate() and d_obtain_alias() from information in the inode (if one is given). The type is cleared by dentry_unlink_inode() when it reconstitutes an existing dentry as a negative dentry. Accessors provided are: d_set_type(dentry, type) d_is_directory(dentry) d_is_autodir(dentry) d_is_symlink(dentry) d_is_file(dentry) d_is_negative(dentry) d_is_positive(dentry) A bunch of checks in pathname resolution switched to those. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
parent
afabada957
commit
b18825a7c8
42
fs/dcache.c
42
fs/dcache.c
@ -343,6 +343,7 @@ static void dentry_unlink_inode(struct dentry * dentry)
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__releases(dentry->d_inode->i_lock)
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{
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struct inode *inode = dentry->d_inode;
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__d_clear_type(dentry);
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dentry->d_inode = NULL;
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hlist_del_init(&dentry->d_alias);
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dentry_rcuwalk_barrier(dentry);
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@ -1648,14 +1649,42 @@ void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op)
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}
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EXPORT_SYMBOL(d_set_d_op);
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static unsigned d_flags_for_inode(struct inode *inode)
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{
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unsigned add_flags = DCACHE_FILE_TYPE;
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if (!inode)
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return DCACHE_MISS_TYPE;
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if (S_ISDIR(inode->i_mode)) {
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add_flags = DCACHE_DIRECTORY_TYPE;
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if (unlikely(!(inode->i_opflags & IOP_LOOKUP))) {
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if (unlikely(!inode->i_op->lookup))
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add_flags = DCACHE_AUTODIR_TYPE;
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else
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inode->i_opflags |= IOP_LOOKUP;
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}
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} else if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) {
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if (unlikely(inode->i_op->follow_link))
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add_flags = DCACHE_SYMLINK_TYPE;
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else
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inode->i_opflags |= IOP_NOFOLLOW;
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}
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if (unlikely(IS_AUTOMOUNT(inode)))
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add_flags |= DCACHE_NEED_AUTOMOUNT;
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return add_flags;
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}
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static void __d_instantiate(struct dentry *dentry, struct inode *inode)
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{
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unsigned add_flags = d_flags_for_inode(inode);
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spin_lock(&dentry->d_lock);
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if (inode) {
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if (unlikely(IS_AUTOMOUNT(inode)))
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dentry->d_flags |= DCACHE_NEED_AUTOMOUNT;
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dentry->d_flags &= ~DCACHE_ENTRY_TYPE;
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dentry->d_flags |= add_flags;
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if (inode)
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hlist_add_head(&dentry->d_alias, &inode->i_dentry);
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}
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dentry->d_inode = inode;
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dentry_rcuwalk_barrier(dentry);
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spin_unlock(&dentry->d_lock);
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@ -1860,6 +1889,7 @@ struct dentry *d_obtain_alias(struct inode *inode)
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static const struct qstr anonstring = QSTR_INIT("/", 1);
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struct dentry *tmp;
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struct dentry *res;
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unsigned add_flags;
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if (!inode)
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return ERR_PTR(-ESTALE);
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@ -1885,9 +1915,11 @@ struct dentry *d_obtain_alias(struct inode *inode)
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}
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/* attach a disconnected dentry */
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add_flags = d_flags_for_inode(inode) | DCACHE_DISCONNECTED;
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spin_lock(&tmp->d_lock);
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tmp->d_inode = inode;
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tmp->d_flags |= DCACHE_DISCONNECTED;
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tmp->d_flags |= add_flags;
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hlist_add_head(&tmp->d_alias, &inode->i_dentry);
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hlist_bl_lock(&tmp->d_sb->s_anon);
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hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon);
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95
fs/namei.c
95
fs/namei.c
@ -1501,18 +1501,9 @@ static void terminate_walk(struct nameidata *nd)
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* so we keep a cache of "no, this doesn't need follow_link"
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* for the common case.
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*/
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static inline int should_follow_link(struct inode *inode, int follow)
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static inline int should_follow_link(struct dentry *dentry, int follow)
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{
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if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) {
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if (likely(inode->i_op->follow_link))
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return follow;
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/* This gets set once for the inode lifetime */
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spin_lock(&inode->i_lock);
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inode->i_opflags |= IOP_NOFOLLOW;
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spin_unlock(&inode->i_lock);
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}
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return 0;
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return unlikely(d_is_symlink(dentry)) ? follow : 0;
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}
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static inline int walk_component(struct nameidata *nd, struct path *path,
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@ -1542,7 +1533,7 @@ static inline int walk_component(struct nameidata *nd, struct path *path,
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if (!inode)
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goto out_path_put;
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if (should_follow_link(inode, follow)) {
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if (should_follow_link(path->dentry, follow)) {
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if (nd->flags & LOOKUP_RCU) {
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if (unlikely(unlazy_walk(nd, path->dentry))) {
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err = -ECHILD;
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@ -1600,26 +1591,6 @@ static inline int nested_symlink(struct path *path, struct nameidata *nd)
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return res;
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}
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/*
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* We really don't want to look at inode->i_op->lookup
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* when we don't have to. So we keep a cache bit in
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* the inode ->i_opflags field that says "yes, we can
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* do lookup on this inode".
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*/
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static inline int can_lookup(struct inode *inode)
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{
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if (likely(inode->i_opflags & IOP_LOOKUP))
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return 1;
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if (likely(!inode->i_op->lookup))
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return 0;
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/* We do this once for the lifetime of the inode */
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spin_lock(&inode->i_lock);
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inode->i_opflags |= IOP_LOOKUP;
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spin_unlock(&inode->i_lock);
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return 1;
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}
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/*
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* We can do the critical dentry name comparison and hashing
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* operations one word at a time, but we are limited to:
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@ -1823,7 +1794,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)
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if (err)
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return err;
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}
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if (!can_lookup(nd->inode)) {
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if (!d_is_directory(nd->path.dentry)) {
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err = -ENOTDIR;
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break;
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}
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@ -1841,9 +1812,10 @@ static int path_init(int dfd, const char *name, unsigned int flags,
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nd->flags = flags | LOOKUP_JUMPED;
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nd->depth = 0;
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if (flags & LOOKUP_ROOT) {
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struct inode *inode = nd->root.dentry->d_inode;
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struct dentry *root = nd->root.dentry;
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struct inode *inode = root->d_inode;
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if (*name) {
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if (!can_lookup(inode))
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if (!d_is_directory(root))
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return -ENOTDIR;
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retval = inode_permission(inode, MAY_EXEC);
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if (retval)
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@ -1899,7 +1871,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
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dentry = f.file->f_path.dentry;
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if (*name) {
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if (!can_lookup(dentry->d_inode)) {
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if (!d_is_directory(dentry)) {
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fdput(f);
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return -ENOTDIR;
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}
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@ -1981,7 +1953,7 @@ static int path_lookupat(int dfd, const char *name,
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err = complete_walk(nd);
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if (!err && nd->flags & LOOKUP_DIRECTORY) {
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if (!can_lookup(nd->inode)) {
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if (!d_is_directory(nd->path.dentry)) {
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path_put(&nd->path);
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err = -ENOTDIR;
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}
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@ -2273,7 +2245,7 @@ done:
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}
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path->dentry = dentry;
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path->mnt = mntget(nd->path.mnt);
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if (should_follow_link(dentry->d_inode, nd->flags & LOOKUP_FOLLOW))
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if (should_follow_link(dentry, nd->flags & LOOKUP_FOLLOW))
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return 1;
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follow_mount(path);
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error = 0;
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@ -2417,12 +2389,14 @@ static inline int check_sticky(struct inode *dir, struct inode *inode)
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* 10. We don't allow removal of NFS sillyrenamed files; it's handled by
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* nfs_async_unlink().
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*/
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static int may_delete(struct inode *dir,struct dentry *victim,int isdir)
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static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
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{
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struct inode *inode = victim->d_inode;
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int error;
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if (!victim->d_inode)
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if (d_is_negative(victim))
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return -ENOENT;
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BUG_ON(!inode);
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BUG_ON(victim->d_parent->d_inode != dir);
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audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
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@ -2432,15 +2406,16 @@ static int may_delete(struct inode *dir,struct dentry *victim,int isdir)
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return error;
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if (IS_APPEND(dir))
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return -EPERM;
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if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)||
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IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode))
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if (check_sticky(dir, inode) || IS_APPEND(inode) ||
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IS_IMMUTABLE(inode) || IS_SWAPFILE(inode))
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return -EPERM;
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if (isdir) {
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if (!S_ISDIR(victim->d_inode->i_mode))
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if (!d_is_directory(victim) && !d_is_autodir(victim))
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return -ENOTDIR;
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if (IS_ROOT(victim))
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return -EBUSY;
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} else if (S_ISDIR(victim->d_inode->i_mode))
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} else if (d_is_directory(victim) || d_is_autodir(victim))
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return -EISDIR;
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if (IS_DEADDIR(dir))
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return -ENOENT;
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@ -2974,7 +2949,7 @@ retry_lookup:
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/*
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* create/update audit record if it already exists.
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*/
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if (path->dentry->d_inode)
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if (d_is_positive(path->dentry))
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audit_inode(name, path->dentry, 0);
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/*
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@ -3003,12 +2978,12 @@ retry_lookup:
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finish_lookup:
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/* we _can_ be in RCU mode here */
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error = -ENOENT;
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if (!inode) {
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if (d_is_negative(path->dentry)) {
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path_to_nameidata(path, nd);
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goto out;
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}
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if (should_follow_link(inode, !symlink_ok)) {
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if (should_follow_link(path->dentry, !symlink_ok)) {
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if (nd->flags & LOOKUP_RCU) {
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if (unlikely(unlazy_walk(nd, path->dentry))) {
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error = -ECHILD;
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@ -3037,10 +3012,11 @@ finish_open:
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}
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audit_inode(name, nd->path.dentry, 0);
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error = -EISDIR;
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if ((open_flag & O_CREAT) && S_ISDIR(nd->inode->i_mode))
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if ((open_flag & O_CREAT) &&
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(d_is_directory(nd->path.dentry) || d_is_autodir(nd->path.dentry)))
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goto out;
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error = -ENOTDIR;
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if ((nd->flags & LOOKUP_DIRECTORY) && !can_lookup(nd->inode))
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if ((nd->flags & LOOKUP_DIRECTORY) && !d_is_directory(nd->path.dentry))
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goto out;
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if (!S_ISREG(nd->inode->i_mode))
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will_truncate = false;
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@ -3266,7 +3242,7 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
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nd.root.mnt = mnt;
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nd.root.dentry = dentry;
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if (dentry->d_inode->i_op->follow_link && op->intent & LOOKUP_OPEN)
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if (d_is_symlink(dentry) && op->intent & LOOKUP_OPEN)
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return ERR_PTR(-ELOOP);
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file = path_openat(-1, &filename, &nd, op, flags | LOOKUP_RCU);
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@ -3316,8 +3292,9 @@ struct dentry *kern_path_create(int dfd, const char *pathname,
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goto unlock;
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error = -EEXIST;
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if (dentry->d_inode)
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if (d_is_positive(dentry))
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goto fail;
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/*
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* Special case - lookup gave negative, but... we had foo/bar/
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* From the vfs_mknod() POV we just have a negative dentry -
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@ -3706,7 +3683,7 @@ retry:
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if (nd.last.name[nd.last.len])
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goto slashes;
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inode = dentry->d_inode;
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if (!inode)
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if (d_is_negative(dentry))
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goto slashes;
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ihold(inode);
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error = security_path_unlink(&nd.path, dentry);
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@ -3731,8 +3708,12 @@ exit1:
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return error;
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slashes:
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error = !dentry->d_inode ? -ENOENT :
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S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR;
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if (d_is_negative(dentry))
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error = -ENOENT;
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else if (d_is_directory(dentry) || d_is_autodir(dentry))
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error = -EISDIR;
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else
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error = -ENOTDIR;
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goto exit2;
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}
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@ -4046,7 +4027,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
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struct inode *new_dir, struct dentry *new_dentry)
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{
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int error;
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int is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
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int is_dir = d_is_directory(old_dentry) || d_is_autodir(old_dentry);
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const unsigned char *old_name;
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if (old_dentry->d_inode == new_dentry->d_inode)
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@ -4134,10 +4115,10 @@ retry:
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goto exit3;
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/* source must exist */
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error = -ENOENT;
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if (!old_dentry->d_inode)
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if (d_is_negative(old_dentry))
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goto exit4;
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/* unless the source is a directory trailing slashes give -ENOTDIR */
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if (!S_ISDIR(old_dentry->d_inode->i_mode)) {
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if (!d_is_directory(old_dentry) && !d_is_autodir(old_dentry)) {
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error = -ENOTDIR;
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if (oldnd.last.name[oldnd.last.len])
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goto exit4;
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@ -169,13 +169,13 @@ struct dentry_operations {
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*/
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/* d_flags entries */
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#define DCACHE_OP_HASH 0x0001
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#define DCACHE_OP_COMPARE 0x0002
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#define DCACHE_OP_REVALIDATE 0x0004
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#define DCACHE_OP_DELETE 0x0008
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#define DCACHE_OP_PRUNE 0x0010
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#define DCACHE_OP_HASH 0x00000001
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#define DCACHE_OP_COMPARE 0x00000002
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#define DCACHE_OP_REVALIDATE 0x00000004
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#define DCACHE_OP_DELETE 0x00000008
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#define DCACHE_OP_PRUNE 0x00000010
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#define DCACHE_DISCONNECTED 0x0020
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#define DCACHE_DISCONNECTED 0x00000020
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/* This dentry is possibly not currently connected to the dcache tree, in
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* which case its parent will either be itself, or will have this flag as
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* well. nfsd will not use a dentry with this bit set, but will first
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@ -186,30 +186,38 @@ struct dentry_operations {
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* dentry into place and return that dentry rather than the passed one,
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* typically using d_splice_alias. */
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#define DCACHE_REFERENCED 0x0040 /* Recently used, don't discard. */
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#define DCACHE_RCUACCESS 0x0080 /* Entry has ever been RCU-visible */
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#define DCACHE_REFERENCED 0x00000040 /* Recently used, don't discard. */
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#define DCACHE_RCUACCESS 0x00000080 /* Entry has ever been RCU-visible */
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#define DCACHE_CANT_MOUNT 0x0100
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#define DCACHE_GENOCIDE 0x0200
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#define DCACHE_SHRINK_LIST 0x0400
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#define DCACHE_CANT_MOUNT 0x00000100
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#define DCACHE_GENOCIDE 0x00000200
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#define DCACHE_SHRINK_LIST 0x00000400
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#define DCACHE_OP_WEAK_REVALIDATE 0x0800
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#define DCACHE_OP_WEAK_REVALIDATE 0x00000800
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#define DCACHE_NFSFS_RENAMED 0x1000
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#define DCACHE_NFSFS_RENAMED 0x00001000
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/* this dentry has been "silly renamed" and has to be deleted on the last
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* dput() */
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#define DCACHE_COOKIE 0x2000 /* For use by dcookie subsystem */
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#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x4000
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#define DCACHE_COOKIE 0x00002000 /* For use by dcookie subsystem */
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#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000
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/* Parent inode is watched by some fsnotify listener */
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#define DCACHE_MOUNTED 0x10000 /* is a mountpoint */
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#define DCACHE_NEED_AUTOMOUNT 0x20000 /* handle automount on this dir */
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#define DCACHE_MANAGE_TRANSIT 0x40000 /* manage transit from this dirent */
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#define DCACHE_DENTRY_KILLED 0x00008000
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#define DCACHE_MOUNTED 0x00010000 /* is a mountpoint */
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#define DCACHE_NEED_AUTOMOUNT 0x00020000 /* handle automount on this dir */
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#define DCACHE_MANAGE_TRANSIT 0x00040000 /* manage transit from this dirent */
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#define DCACHE_MANAGED_DENTRY \
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(DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT)
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#define DCACHE_LRU_LIST 0x80000
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#define DCACHE_DENTRY_KILLED 0x100000
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#define DCACHE_LRU_LIST 0x00080000
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#define DCACHE_ENTRY_TYPE 0x00700000
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#define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry */
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#define DCACHE_DIRECTORY_TYPE 0x00100000 /* Normal directory */
|
||||
#define DCACHE_AUTODIR_TYPE 0x00200000 /* Lookupless directory (presumed automount) */
|
||||
#define DCACHE_SYMLINK_TYPE 0x00300000 /* Symlink */
|
||||
#define DCACHE_FILE_TYPE 0x00400000 /* Other file type */
|
||||
|
||||
extern seqlock_t rename_lock;
|
||||
|
||||
@ -394,6 +402,61 @@ static inline bool d_mountpoint(const struct dentry *dentry)
|
||||
return dentry->d_flags & DCACHE_MOUNTED;
|
||||
}
|
||||
|
||||
/*
|
||||
* Directory cache entry type accessor functions.
|
||||
*/
|
||||
static inline void __d_set_type(struct dentry *dentry, unsigned type)
|
||||
{
|
||||
dentry->d_flags = (dentry->d_flags & ~DCACHE_ENTRY_TYPE) | type;
|
||||
}
|
||||
|
||||
static inline void __d_clear_type(struct dentry *dentry)
|
||||
{
|
||||
__d_set_type(dentry, DCACHE_MISS_TYPE);
|
||||
}
|
||||
|
||||
static inline void d_set_type(struct dentry *dentry, unsigned type)
|
||||
{
|
||||
spin_lock(&dentry->d_lock);
|
||||
__d_set_type(dentry, type);
|
||||
spin_unlock(&dentry->d_lock);
|
||||
}
|
||||
|
||||
static inline unsigned __d_entry_type(const struct dentry *dentry)
|
||||
{
|
||||
return dentry->d_flags & DCACHE_ENTRY_TYPE;
|
||||
}
|
||||
|
||||
static inline bool d_is_directory(const struct dentry *dentry)
|
||||
{
|
||||
return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
|
||||
}
|
||||
|
||||
static inline bool d_is_autodir(const struct dentry *dentry)
|
||||
{
|
||||
return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE;
|
||||
}
|
||||
|
||||
static inline bool d_is_symlink(const struct dentry *dentry)
|
||||
{
|
||||
return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
|
||||
}
|
||||
|
||||
static inline bool d_is_file(const struct dentry *dentry)
|
||||
{
|
||||
return __d_entry_type(dentry) == DCACHE_FILE_TYPE;
|
||||
}
|
||||
|
||||
static inline bool d_is_negative(const struct dentry *dentry)
|
||||
{
|
||||
return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
|
||||
}
|
||||
|
||||
static inline bool d_is_positive(const struct dentry *dentry)
|
||||
{
|
||||
return !d_is_negative(dentry);
|
||||
}
|
||||
|
||||
extern int sysctl_vfs_cache_pressure;
|
||||
|
||||
static inline unsigned long vfs_pressure_ratio(unsigned long val)
|
||||
|
Loading…
Reference in New Issue
Block a user