#include <linux/syscalls.h>
#include <linux/string.h>
#include <linux/mm.h>
-#include <linux/fdtable.h>
#include <linux/fs.h>
#include <linux/fsnotify.h>
#include <linux/slab.h>
#include <linux/seqlock.h>
#include <linux/swap.h>
#include <linux/bootmem.h>
+#include <linux/fs_struct.h>
#include "internal.h"
-
int sysctl_vfs_cache_pressure __read_mostly = 100;
EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure);
static void __d_free(struct dentry *dentry)
{
+ WARN_ON(!list_empty(&dentry->d_alias));
if (dname_external(dentry))
kfree(dentry->d_name.name);
kmem_cache_free(dentry_cache, dentry);
dentry_stat.nr_dentry--; /* For d_free, below */
/*drops the locks, at that point nobody can reach this dentry */
dentry_iput(dentry);
- parent = dentry->d_parent;
+ if (IS_ROOT(dentry))
+ parent = NULL;
+ else
+ parent = dentry->d_parent;
d_free(dentry);
- return dentry == parent ? NULL : parent;
+ return parent;
}
/*
if ((flags & DCACHE_REFERENCED)
&& (dentry->d_flags & DCACHE_REFERENCED)) {
dentry->d_flags &= ~DCACHE_REFERENCED;
- list_move_tail(&dentry->d_lru, &referenced);
+ list_move(&dentry->d_lru, &referenced);
spin_unlock(&dentry->d_lock);
} else {
list_move_tail(&dentry->d_lru, &tmp);
BUG();
}
- parent = dentry->d_parent;
- if (parent == dentry)
+ if (IS_ROOT(dentry))
parent = NULL;
- else
+ else {
+ parent = dentry->d_parent;
atomic_dec(&parent->d_count);
+ }
list_del(&dentry->d_u.d_child);
detached++;
dentry->d_op = NULL;
dentry->d_fsdata = NULL;
dentry->d_mounted = 0;
-#ifdef CONFIG_PROFILING
- dentry->d_cookie = NULL;
-#endif
INIT_HLIST_NODE(&dentry->d_hash);
INIT_LIST_HEAD(&dentry->d_lru);
INIT_LIST_HEAD(&dentry->d_subdirs);
return d_alloc(parent, &q);
}
+/* the caller must hold dcache_lock */
+static void __d_instantiate(struct dentry *dentry, struct inode *inode)
+{
+ if (inode)
+ list_add(&dentry->d_alias, &inode->i_dentry);
+ dentry->d_inode = inode;
+ fsnotify_d_instantiate(dentry, inode);
+}
+
/**
* d_instantiate - fill in inode information for a dentry
* @entry: dentry to complete
{
BUG_ON(!list_empty(&entry->d_alias));
spin_lock(&dcache_lock);
- if (inode)
- list_add(&entry->d_alias, &inode->i_dentry);
- entry->d_inode = inode;
- fsnotify_d_instantiate(entry, inode);
+ __d_instantiate(entry, inode);
spin_unlock(&dcache_lock);
security_d_instantiate(entry, inode);
}
unsigned int hash = entry->d_name.hash;
if (!inode) {
- entry->d_inode = NULL;
+ __d_instantiate(entry, NULL);
return NULL;
}
return alias;
}
- list_add(&entry->d_alias, &inode->i_dentry);
- entry->d_inode = inode;
- fsnotify_d_instantiate(entry, inode);
+ __d_instantiate(entry, inode);
return NULL;
}
}
/**
- * d_alloc_anon - allocate an anonymous dentry
+ * d_obtain_alias - find or allocate a dentry for a given inode
* @inode: inode to allocate the dentry for
*
- * This is similar to d_alloc_root. It is used by filesystems when
- * creating a dentry for a given inode, often in the process of
- * mapping a filehandle to a dentry. The returned dentry may be
- * anonymous, or may have a full name (if the inode was already
- * in the cache). The file system may need to make further
- * efforts to connect this dentry into the dcache properly.
+ * Obtain a dentry for an inode resulting from NFS filehandle conversion or
+ * similar open by handle operations. The returned dentry may be anonymous,
+ * or may have a full name (if the inode was already in the cache).
*
- * When called on a directory inode, we must ensure that
- * the inode only ever has one dentry. If a dentry is
- * found, that is returned instead of allocating a new one.
+ * When called on a directory inode, we must ensure that the inode only ever
+ * has one dentry. If a dentry is found, that is returned instead of
+ * allocating a new one.
*
* On successful return, the reference to the inode has been transferred
- * to the dentry. If %NULL is returned (indicating kmalloc failure),
- * the reference on the inode has not been released.
+ * to the dentry. In case of an error the reference on the inode is released.
+ * To make it easier to use in export operations a %NULL or IS_ERR inode may
+ * be passed in and will be the error will be propagate to the return value,
+ * with a %NULL @inode replaced by ERR_PTR(-ESTALE).
*/
-
-struct dentry * d_alloc_anon(struct inode *inode)
+struct dentry *d_obtain_alias(struct inode *inode)
{
static const struct qstr anonstring = { .name = "" };
struct dentry *tmp;
struct dentry *res;
- if ((res = d_find_alias(inode))) {
- iput(inode);
- return res;
- }
+ if (!inode)
+ return ERR_PTR(-ESTALE);
+ if (IS_ERR(inode))
+ return ERR_CAST(inode);
- tmp = d_alloc(NULL, &anonstring);
- if (!tmp)
- return NULL;
+ res = d_find_alias(inode);
+ if (res)
+ goto out_iput;
+ tmp = d_alloc(NULL, &anonstring);
+ if (!tmp) {
+ res = ERR_PTR(-ENOMEM);
+ goto out_iput;
+ }
tmp->d_parent = tmp; /* make sure dput doesn't croak */
-
+
spin_lock(&dcache_lock);
res = __d_find_alias(inode, 0);
- if (!res) {
- /* attach a disconnected dentry */
- res = tmp;
- tmp = NULL;
- spin_lock(&res->d_lock);
- res->d_sb = inode->i_sb;
- res->d_parent = res;
- res->d_inode = inode;
- res->d_flags |= DCACHE_DISCONNECTED;
- res->d_flags &= ~DCACHE_UNHASHED;
- list_add(&res->d_alias, &inode->i_dentry);
- hlist_add_head(&res->d_hash, &inode->i_sb->s_anon);
- spin_unlock(&res->d_lock);
-
- inode = NULL; /* don't drop reference */
+ if (res) {
+ spin_unlock(&dcache_lock);
+ dput(tmp);
+ goto out_iput;
}
+
+ /* attach a disconnected dentry */
+ spin_lock(&tmp->d_lock);
+ tmp->d_sb = inode->i_sb;
+ tmp->d_inode = inode;
+ tmp->d_flags |= DCACHE_DISCONNECTED;
+ tmp->d_flags &= ~DCACHE_UNHASHED;
+ list_add(&tmp->d_alias, &inode->i_dentry);
+ hlist_add_head(&tmp->d_hash, &inode->i_sb->s_anon);
+ spin_unlock(&tmp->d_lock);
+
spin_unlock(&dcache_lock);
+ return tmp;
- if (inode)
- iput(inode);
- if (tmp)
- dput(tmp);
+ out_iput:
+ iput(inode);
return res;
}
-
+EXPORT_SYMBOL(d_obtain_alias);
/**
* d_splice_alias - splice a disconnected dentry into the tree if one exists
new = __d_find_alias(inode, 1);
if (new) {
BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED));
- fsnotify_d_instantiate(new, inode);
spin_unlock(&dcache_lock);
security_d_instantiate(new, inode);
d_rehash(dentry);
d_move(new, dentry);
iput(inode);
} else {
- /* d_instantiate takes dcache_lock, so we do it by hand */
- list_add(&dentry->d_alias, &inode->i_dentry);
- dentry->d_inode = inode;
- fsnotify_d_instantiate(dentry, inode);
+ /* already taking dcache_lock, so d_add() by hand */
+ __d_instantiate(dentry, inode);
spin_unlock(&dcache_lock);
security_d_instantiate(dentry, inode);
d_rehash(dentry);
return new;
}
+/**
+ * d_add_ci - lookup or allocate new dentry with case-exact name
+ * @inode: the inode case-insensitive lookup has found
+ * @dentry: the negative dentry that was passed to the parent's lookup func
+ * @name: the case-exact name to be associated with the returned dentry
+ *
+ * This is to avoid filling the dcache with case-insensitive names to the
+ * same inode, only the actual correct case is stored in the dcache for
+ * case-insensitive filesystems.
+ *
+ * For a case-insensitive lookup match and if the the case-exact dentry
+ * already exists in in the dcache, use it and return it.
+ *
+ * If no entry exists with the exact case name, allocate new dentry with
+ * the exact case, and return the spliced entry.
+ */
+struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
+ struct qstr *name)
+{
+ int error;
+ struct dentry *found;
+ struct dentry *new;
+
+ /*
+ * First check if a dentry matching the name already exists,
+ * if not go ahead and create it now.
+ */
+ found = d_hash_and_lookup(dentry->d_parent, name);
+ if (!found) {
+ new = d_alloc(dentry->d_parent, name);
+ if (!new) {
+ error = -ENOMEM;
+ goto err_out;
+ }
+
+ found = d_splice_alias(inode, new);
+ if (found) {
+ dput(new);
+ return found;
+ }
+ return new;
+ }
+
+ /*
+ * If a matching dentry exists, and it's not negative use it.
+ *
+ * Decrement the reference count to balance the iget() done
+ * earlier on.
+ */
+ if (found->d_inode) {
+ if (unlikely(found->d_inode != inode)) {
+ /* This can't happen because bad inodes are unhashed. */
+ BUG_ON(!is_bad_inode(inode));
+ BUG_ON(!is_bad_inode(found->d_inode));
+ }
+ iput(inode);
+ return found;
+ }
+
+ /*
+ * Negative dentry: instantiate it unless the inode is a directory and
+ * already has a dentry.
+ */
+ spin_lock(&dcache_lock);
+ if (!S_ISDIR(inode->i_mode) || list_empty(&inode->i_dentry)) {
+ __d_instantiate(found, inode);
+ spin_unlock(&dcache_lock);
+ security_d_instantiate(found, inode);
+ return found;
+ }
+
+ /*
+ * In case a directory already has a (disconnected) entry grab a
+ * reference to it, move it in place and use it.
+ */
+ new = list_entry(inode->i_dentry.next, struct dentry, d_alias);
+ dget_locked(new);
+ spin_unlock(&dcache_lock);
+ security_d_instantiate(found, inode);
+ d_move(new, found);
+ iput(inode);
+ dput(found);
+ return new;
+
+err_out:
+ iput(inode);
+ return ERR_PTR(error);
+}
/**
* d_lookup - search for a dentry
*
* Searches the children of the parent dentry for the name in question. If
* the dentry is found its reference count is incremented and the dentry
- * is returned. The caller must use d_put to free the entry when it has
+ * is returned. The caller must use dput to free the entry when it has
* finished using it. %NULL is returned on failure.
*
* __d_lookup is dcache_lock free. The hash list is protected using RCU.
if (dentry->d_parent != parent)
goto next;
+ /* non-existing due to RCU? */
+ if (d_unhashed(dentry))
+ goto next;
+
/*
* It is safe to compare names since d_move() cannot
* change the qstr (protected by d_lock).
goto next;
}
- if (!d_unhashed(dentry)) {
- atomic_inc(&dentry->d_count);
- found = dentry;
- }
+ atomic_inc(&dentry->d_count);
+ found = dentry;
spin_unlock(&dentry->d_lock);
break;
next:
* d_validate - verify dentry provided from insecure source
* @dentry: The dentry alleged to be valid child of @dparent
* @dparent: The parent dentry (known to be valid)
- * @hash: Hash of the dentry
- * @len: Length of the name
*
* An insecure source has sent us a dentry, here we verify it and dget() it.
* This is used by ncpfs in its readdir implementation.
spin_unlock(&dcache_lock);
}
-#define do_switch(x,y) do { \
- __typeof__ (x) __tmp = x; \
- x = y; y = __tmp; } while (0)
-
/*
* When switching names, the actual string doesn't strictly have to
* be preserved in the target - because we're dropping the target
/*
* Both external: swap the pointers
*/
- do_switch(target->d_name.name, dentry->d_name.name);
+ swap(target->d_name.name, dentry->d_name.name);
} else {
/*
* dentry:internal, target:external. Steal target's
*/
memcpy(dentry->d_iname, target->d_name.name,
target->d_name.len + 1);
+ dentry->d_name.len = target->d_name.len;
+ return;
}
}
+ swap(dentry->d_name.len, target->d_name.len);
}
/*
/* Switch the names.. */
switch_names(dentry, target);
- do_switch(dentry->d_name.len, target->d_name.len);
- do_switch(dentry->d_name.hash, target->d_name.hash);
+ swap(dentry->d_name.hash, target->d_name.hash);
/* ... and switch the parents */
if (IS_ROOT(dentry)) {
target->d_parent = target;
INIT_LIST_HEAD(&target->d_u.d_child);
} else {
- do_switch(dentry->d_parent, target->d_parent);
+ swap(dentry->d_parent, target->d_parent);
/* And add them back to the (new) parent lists */
list_add(&target->d_u.d_child, &target->d_parent->d_subdirs);
spin_unlock(&dcache_lock);
}
-/*
- * Helper that returns 1 if p1 is a parent of p2, else 0
+/**
+ * d_ancestor - search for an ancestor
+ * @p1: ancestor dentry
+ * @p2: child dentry
+ *
+ * Returns the ancestor dentry of p2 which is a child of p1, if p1 is
+ * an ancestor of p2, else NULL.
*/
-static int d_isparent(struct dentry *p1, struct dentry *p2)
+struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2)
{
struct dentry *p;
- for (p = p2; p->d_parent != p; p = p->d_parent) {
+ for (p = p2; !IS_ROOT(p); p = p->d_parent) {
if (p->d_parent == p1)
- return 1;
+ return p;
}
- return 0;
+ return NULL;
}
/*
/* Check for loops */
ret = ERR_PTR(-ELOOP);
- if (d_isparent(alias, dentry))
+ if (d_ancestor(alias, dentry))
goto out_err;
/* See lock_rename() */
struct dentry *dparent, *aparent;
switch_names(dentry, anon);
- do_switch(dentry->d_name.len, anon->d_name.len);
- do_switch(dentry->d_name.hash, anon->d_name.hash);
+ swap(dentry->d_name.hash, anon->d_name.hash);
dparent = dentry->d_parent;
aparent = anon->d_parent;
if (!inode) {
actual = dentry;
- dentry->d_inode = NULL;
+ __d_instantiate(dentry, NULL);
goto found_lock;
}
* Convert a dentry into an ASCII path name. If the entry has been deleted
* the string " (deleted)" is appended. Note that this is ambiguous.
*
- * Returns the buffer or an error code if the path was too long.
+ * Returns a pointer into the buffer or an error code if the
+ * path was too long.
*
* "buflen" should be positive. Caller holds the dcache_lock.
*
* Convert a dentry into an ASCII path name. If the entry has been deleted
* the string " (deleted)" is appended. Note that this is ambiguous.
*
- * Returns the buffer or an error code if the path was too long.
+ * Returns a pointer into the buffer or an error code if the path was
+ * too long. Note: Callers should use the returned pointer, not the passed
+ * in buffer, to use the name! The implementation often starts at an offset
+ * into the buffer, and may leave 0 bytes at the start.
*
* "buflen" should be positive.
*/
* return NULL;
* }
*/
-asmlinkage long sys_getcwd(char __user *buf, unsigned long size)
+SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
{
int error;
struct path pwd, root;
* Caller must ensure that "new_dentry" is pinned before calling is_subdir()
*/
-int is_subdir(struct dentry * new_dentry, struct dentry * old_dentry)
+int is_subdir(struct dentry *new_dentry, struct dentry *old_dentry)
{
int result;
- struct dentry * saved = new_dentry;
unsigned long seq;
- /* need rcu_readlock to protect against the d_parent trashing due to
- * d_move
+ if (new_dentry == old_dentry)
+ return 1;
+
+ /*
+ * Need rcu_readlock to protect against the d_parent trashing
+ * due to d_move
*/
rcu_read_lock();
- do {
+ do {
/* for restarting inner loop in case of seq retry */
- new_dentry = saved;
- result = 0;
seq = read_seqbegin(&rename_lock);
- for (;;) {
- if (new_dentry != old_dentry) {
- struct dentry * parent = new_dentry->d_parent;
- if (parent == new_dentry)
- break;
- new_dentry = parent;
- continue;
- }
+ if (d_ancestor(old_dentry, new_dentry))
result = 1;
- break;
- }
+ else
+ result = 0;
} while (read_seqretry(&rename_lock, seq));
rcu_read_unlock();
/* SLAB cache for __getname() consumers */
struct kmem_cache *names_cachep __read_mostly;
-/* SLAB cache for file structures */
-struct kmem_cache *filp_cachep __read_mostly;
-
EXPORT_SYMBOL(d_genocide);
void __init vfs_caches_init_early(void)
names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0,
SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
- filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0,
- SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
-
dcache_init();
inode_init();
files_init(mempages);
}
EXPORT_SYMBOL(d_alloc);
-EXPORT_SYMBOL(d_alloc_anon);
EXPORT_SYMBOL(d_alloc_root);
EXPORT_SYMBOL(d_delete);
EXPORT_SYMBOL(d_find_alias);
EXPORT_SYMBOL(d_prune_aliases);
EXPORT_SYMBOL(d_rehash);
EXPORT_SYMBOL(d_splice_alias);
+EXPORT_SYMBOL(d_add_ci);
EXPORT_SYMBOL(d_validate);
EXPORT_SYMBOL(dget_locked);
EXPORT_SYMBOL(dput);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff