/*
* This does basic POSIX ACL permission checking
*/
-static int acl_permission_check(struct inode *inode, int mask,
- int (*check_acl)(struct inode *inode, int mask))
+static int acl_permission_check(struct inode *inode, int mask, unsigned int flags,
+ int (*check_acl)(struct inode *inode, int mask, unsigned int flags))
{
umode_t mode = inode->i_mode;
mode >>= 6;
else {
if (IS_POSIXACL(inode) && (mode & S_IRWXG) && check_acl) {
- int error = check_acl(inode, mask);
+ int error = check_acl(inode, mask, flags);
if (error != -EAGAIN)
return error;
}
}
/**
- * generic_permission - check for access rights on a Posix-like filesystem
+ * generic_permission - check for access rights on a Posix-like filesystem
* @inode: inode to check access rights for
* @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
* @check_acl: optional callback to check for Posix ACLs
+ * @flags: IPERM_FLAG_ flags.
*
* Used to check for read/write/execute permissions on a file.
* We use "fsuid" for this, letting us set arbitrary permissions
* for filesystem access without changing the "normal" uids which
- * are used for other things..
+ * are used for other things.
+ *
+ * generic_permission is rcu-walk aware. It returns -ECHILD in case an rcu-walk
+ * request cannot be satisfied (eg. requires blocking or too much complexity).
+ * It would then be called again in ref-walk mode.
*/
-int generic_permission(struct inode *inode, int mask,
- int (*check_acl)(struct inode *inode, int mask))
+int generic_permission(struct inode *inode, int mask, unsigned int flags,
+ int (*check_acl)(struct inode *inode, int mask, unsigned int flags))
{
int ret;
/*
* Do the basic POSIX ACL permission checks.
*/
- ret = acl_permission_check(inode, mask, check_acl);
+ ret = acl_permission_check(inode, mask, flags, check_acl);
if (ret != -EACCES)
return ret;
}
if (inode->i_op->permission)
- retval = inode->i_op->permission(inode, mask);
+ retval = inode->i_op->permission(inode, mask, 0);
else
- retval = generic_permission(inode, mask, inode->i_op->check_acl);
+ retval = generic_permission(inode, mask, 0,
+ inode->i_op->check_acl);
if (retval)
return retval;
}
EXPORT_SYMBOL(path_put);
+/**
+ * nameidata_drop_rcu - drop this nameidata out of rcu-walk
+ * @nd: nameidata pathwalk data to drop
+ * Returns: 0 on success, -ECHILD on failure
+ *
+ * Path walking has 2 modes, rcu-walk and ref-walk (see
+ * Documentation/filesystems/path-lookup.txt). __drop_rcu* functions attempt
+ * to drop out of rcu-walk mode and take normal reference counts on dentries
+ * and vfsmounts to transition to rcu-walk mode. __drop_rcu* functions take
+ * refcounts at the last known good point before rcu-walk got stuck, so
+ * ref-walk may continue from there. If this is not successful (eg. a seqcount
+ * has changed), then failure is returned and path walk restarts from the
+ * beginning in ref-walk mode.
+ *
+ * nameidata_drop_rcu attempts to drop the current nd->path and nd->root into
+ * ref-walk. Must be called from rcu-walk context.
+ */
+static int nameidata_drop_rcu(struct nameidata *nd)
+{
+ struct fs_struct *fs = current->fs;
+ struct dentry *dentry = nd->path.dentry;
+
+ BUG_ON(!(nd->flags & LOOKUP_RCU));
+ if (nd->root.mnt) {
+ spin_lock(&fs->lock);
+ if (nd->root.mnt != fs->root.mnt ||
+ nd->root.dentry != fs->root.dentry)
+ goto err_root;
+ }
+ spin_lock(&dentry->d_lock);
+ if (!__d_rcu_to_refcount(dentry, nd->seq))
+ goto err;
+ BUG_ON(nd->inode != dentry->d_inode);
+ spin_unlock(&dentry->d_lock);
+ if (nd->root.mnt) {
+ path_get(&nd->root);
+ spin_unlock(&fs->lock);
+ }
+ mntget(nd->path.mnt);
+
+ rcu_read_unlock();
+ br_read_unlock(vfsmount_lock);
+ nd->flags &= ~LOOKUP_RCU;
+ return 0;
+err:
+ spin_unlock(&dentry->d_lock);
+err_root:
+ if (nd->root.mnt)
+ spin_unlock(&fs->lock);
+ return -ECHILD;
+}
+
+/* Try to drop out of rcu-walk mode if we were in it, otherwise do nothing. */
+static inline int nameidata_drop_rcu_maybe(struct nameidata *nd)
+{
+ if (nd->flags & LOOKUP_RCU)
+ return nameidata_drop_rcu(nd);
+ return 0;
+}
+
+/**
+ * nameidata_dentry_drop_rcu - drop nameidata and dentry out of rcu-walk
+ * @nd: nameidata pathwalk data to drop
+ * @dentry: dentry to drop
+ * Returns: 0 on success, -ECHILD on failure
+ *
+ * nameidata_dentry_drop_rcu attempts to drop the current nd->path and nd->root,
+ * and dentry into ref-walk. @dentry must be a path found by a do_lookup call on
+ * @nd. Must be called from rcu-walk context.
+ */
+static int nameidata_dentry_drop_rcu(struct nameidata *nd, struct dentry *dentry)
+{
+ struct fs_struct *fs = current->fs;
+ struct dentry *parent = nd->path.dentry;
+
+ /*
+ * It can be possible to revalidate the dentry that we started
+ * the path walk with. force_reval_path may also revalidate the
+ * dentry already committed to the nameidata.
+ */
+ if (unlikely(parent == dentry))
+ return nameidata_drop_rcu(nd);
+
+ BUG_ON(!(nd->flags & LOOKUP_RCU));
+ if (nd->root.mnt) {
+ spin_lock(&fs->lock);
+ if (nd->root.mnt != fs->root.mnt ||
+ nd->root.dentry != fs->root.dentry)
+ goto err_root;
+ }
+ spin_lock(&parent->d_lock);
+ spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
+ if (!__d_rcu_to_refcount(dentry, nd->seq))
+ goto err;
+ /*
+ * If the sequence check on the child dentry passed, then the child has
+ * not been removed from its parent. This means the parent dentry must
+ * be valid and able to take a reference at this point.
+ */
+ BUG_ON(!IS_ROOT(dentry) && dentry->d_parent != parent);
+ BUG_ON(!parent->d_count);
+ parent->d_count++;
+ spin_unlock(&dentry->d_lock);
+ spin_unlock(&parent->d_lock);
+ if (nd->root.mnt) {
+ path_get(&nd->root);
+ spin_unlock(&fs->lock);
+ }
+ mntget(nd->path.mnt);
+
+ rcu_read_unlock();
+ br_read_unlock(vfsmount_lock);
+ nd->flags &= ~LOOKUP_RCU;
+ return 0;
+err:
+ spin_unlock(&dentry->d_lock);
+ spin_unlock(&parent->d_lock);
+err_root:
+ if (nd->root.mnt)
+ spin_unlock(&fs->lock);
+ return -ECHILD;
+}
+
+/* Try to drop out of rcu-walk mode if we were in it, otherwise do nothing. */
+static inline int nameidata_dentry_drop_rcu_maybe(struct nameidata *nd, struct dentry *dentry)
+{
+ if (nd->flags & LOOKUP_RCU)
+ return nameidata_dentry_drop_rcu(nd, dentry);
+ return 0;
+}
+
+/**
+ * nameidata_drop_rcu_last - drop nameidata ending path walk out of rcu-walk
+ * @nd: nameidata pathwalk data to drop
+ * Returns: 0 on success, -ECHILD on failure
+ *
+ * nameidata_drop_rcu_last attempts to drop the current nd->path into ref-walk.
+ * nd->path should be the final element of the lookup, so nd->root is discarded.
+ * Must be called from rcu-walk context.
+ */
+static int nameidata_drop_rcu_last(struct nameidata *nd)
+{
+ struct dentry *dentry = nd->path.dentry;
+
+ BUG_ON(!(nd->flags & LOOKUP_RCU));
+ nd->flags &= ~LOOKUP_RCU;
+ nd->root.mnt = NULL;
+ spin_lock(&dentry->d_lock);
+ if (!__d_rcu_to_refcount(dentry, nd->seq))
+ goto err_unlock;
+ BUG_ON(nd->inode != dentry->d_inode);
+ spin_unlock(&dentry->d_lock);
+
+ mntget(nd->path.mnt);
+
+ rcu_read_unlock();
+ br_read_unlock(vfsmount_lock);
+
+ return 0;
+
+err_unlock:
+ spin_unlock(&dentry->d_lock);
+ rcu_read_unlock();
+ br_read_unlock(vfsmount_lock);
+ return -ECHILD;
+}
+
+/* Try to drop out of rcu-walk mode if we were in it, otherwise do nothing. */
+static inline int nameidata_drop_rcu_last_maybe(struct nameidata *nd)
+{
+ if (likely(nd->flags & LOOKUP_RCU))
+ return nameidata_drop_rcu_last(nd);
+ return 0;
+}
+
/**
* release_open_intent - free up open intent resources
* @nd: pointer to nameidata
fput(nd->intent.open.file);
}
+/*
+ * Call d_revalidate and handle filesystems that request rcu-walk
+ * to be dropped. This may be called and return in rcu-walk mode,
+ * regardless of success or error. If -ECHILD is returned, the caller
+ * must return -ECHILD back up the path walk stack so path walk may
+ * be restarted in ref-walk mode.
+ */
+static int d_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+ int status;
+
+ status = dentry->d_op->d_revalidate(dentry, nd);
+ if (status == -ECHILD) {
+ if (nameidata_dentry_drop_rcu(nd, dentry))
+ return status;
+ status = dentry->d_op->d_revalidate(dentry, nd);
+ }
+
+ return status;
+}
+
static inline struct dentry *
do_revalidate(struct dentry *dentry, struct nameidata *nd)
{
- int status = dentry->d_op->d_revalidate(dentry, nd);
+ int status;
+
+ status = d_revalidate(dentry, nd);
if (unlikely(status <= 0)) {
/*
* The dentry failed validation.
* the dentry otherwise d_revalidate is asking us
* to return a fail status.
*/
- if (!status) {
+ if (status < 0) {
+ /* If we're in rcu-walk, we don't have a ref */
+ if (!(nd->flags & LOOKUP_RCU))
+ dput(dentry);
+ dentry = ERR_PTR(status);
+
+ } else {
+ /* Don't d_invalidate in rcu-walk mode */
+ if (nameidata_dentry_drop_rcu_maybe(nd, dentry))
+ return ERR_PTR(-ECHILD);
if (!d_invalidate(dentry)) {
dput(dentry);
dentry = NULL;
}
- } else {
- dput(dentry);
- dentry = ERR_PTR(status);
}
}
return dentry;
}
+static inline int need_reval_dot(struct dentry *dentry)
+{
+ if (likely(!(dentry->d_flags & DCACHE_OP_REVALIDATE)))
+ return 0;
+
+ if (likely(!(dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)))
+ return 0;
+
+ return 1;
+}
+
/*
* force_reval_path - force revalidation of a dentry
*
/*
* only check on filesystems where it's possible for the dentry to
- * become stale. It's assumed that if this flag is set then the
- * d_revalidate op will also be defined.
+ * become stale.
*/
- if (!(dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT))
+ if (!need_reval_dot(dentry))
return 0;
- status = dentry->d_op->d_revalidate(dentry, nd);
+ status = d_revalidate(dentry, nd);
if (status > 0)
return 0;
if (!status) {
+ /* Don't d_invalidate in rcu-walk mode */
+ if (nameidata_drop_rcu(nd))
+ return -ECHILD;
d_invalidate(dentry);
status = -ESTALE;
}
* short-cut DAC fails, then call ->permission() to do more
* complete permission check.
*/
-static int exec_permission(struct inode *inode)
+static inline int exec_permission(struct inode *inode, unsigned int flags)
{
int ret;
if (inode->i_op->permission) {
- ret = inode->i_op->permission(inode, MAY_EXEC);
- if (!ret)
- goto ok;
- return ret;
+ ret = inode->i_op->permission(inode, MAY_EXEC, flags);
+ } else {
+ ret = acl_permission_check(inode, MAY_EXEC, flags,
+ inode->i_op->check_acl);
}
- ret = acl_permission_check(inode, MAY_EXEC, inode->i_op->check_acl);
- if (!ret)
+ if (likely(!ret))
goto ok;
+ if (ret == -ECHILD)
+ return ret;
if (capable(CAP_DAC_OVERRIDE) || capable(CAP_DAC_READ_SEARCH))
goto ok;
return ret;
ok:
- return security_inode_permission(inode, MAY_EXEC);
+ return security_inode_exec_permission(inode, flags);
}
static __always_inline void set_root(struct nameidata *nd)
static int link_path_walk(const char *, struct nameidata *);
+static __always_inline void set_root_rcu(struct nameidata *nd)
+{
+ if (!nd->root.mnt) {
+ struct fs_struct *fs = current->fs;
+ unsigned seq;
+
+ do {
+ seq = read_seqcount_begin(&fs->seq);
+ nd->root = fs->root;
+ } while (read_seqcount_retry(&fs->seq, seq));
+ }
+}
+
static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link)
{
+ int ret;
+
if (IS_ERR(link))
goto fail;
nd->path = nd->root;
path_get(&nd->root);
}
+ nd->inode = nd->path.dentry->d_inode;
- return link_path_walk(link, nd);
+ ret = link_path_walk(link, nd);
+ return ret;
fail:
path_put(&nd->path);
return PTR_ERR(link);
mntput(path->mnt);
}
-static inline void path_to_nameidata(struct path *path, struct nameidata *nd)
+static inline void path_to_nameidata(const struct path *path,
+ struct nameidata *nd)
{
- dput(nd->path.dentry);
- if (nd->path.mnt != path->mnt) {
- mntput(nd->path.mnt);
- nd->path.mnt = path->mnt;
+ if (!(nd->flags & LOOKUP_RCU)) {
+ dput(nd->path.dentry);
+ if (nd->path.mnt != path->mnt)
+ mntput(nd->path.mnt);
}
+ nd->path.mnt = path->mnt;
nd->path.dentry = path->dentry;
}
static __always_inline int
-__do_follow_link(struct path *path, struct nameidata *nd, void **p)
+__do_follow_link(const struct path *link, struct nameidata *nd, void **p)
{
int error;
- struct dentry *dentry = path->dentry;
+ struct dentry *dentry = link->dentry;
- touch_atime(path->mnt, dentry);
+ touch_atime(link->mnt, dentry);
nd_set_link(nd, NULL);
- if (path->mnt != nd->path.mnt) {
- path_to_nameidata(path, nd);
- dget(dentry);
- }
- mntget(path->mnt);
+ if (link->mnt == nd->path.mnt)
+ mntget(link->mnt);
+
nd->last_type = LAST_BIND;
*p = dentry->d_inode->i_op->follow_link(dentry, nd);
error = PTR_ERR(*p);
return err;
}
+static int follow_up_rcu(struct path *path)
+{
+ struct vfsmount *parent;
+ struct dentry *mountpoint;
+
+ parent = path->mnt->mnt_parent;
+ if (parent == path->mnt)
+ return 0;
+ mountpoint = path->mnt->mnt_mountpoint;
+ path->dentry = mountpoint;
+ path->mnt = parent;
+ return 1;
+}
+
int follow_up(struct path *path)
{
struct vfsmount *parent;
return 1;
}
-/* no need for dcache_lock, as serialization is taken care in
- * namespace.c
+/*
+ * Perform an automount
+ * - return -EISDIR to tell follow_managed() to stop and return the path we
+ * were called with.
*/
-static int __follow_mount(struct path *path)
+static int follow_automount(struct path *path, unsigned flags,
+ bool *need_mntput)
{
- int res = 0;
- while (d_mountpoint(path->dentry)) {
- struct vfsmount *mounted = lookup_mnt(path);
- if (!mounted)
- break;
+ struct vfsmount *mnt;
+ int err;
+
+ if (!path->dentry->d_op || !path->dentry->d_op->d_automount)
+ return -EREMOTE;
+
+ /* We don't want to mount if someone supplied AT_NO_AUTOMOUNT
+ * and this is the terminal part of the path.
+ */
+ if ((flags & LOOKUP_NO_AUTOMOUNT) && !(flags & LOOKUP_CONTINUE))
+ return -EISDIR; /* we actually want to stop here */
+
+ /* We want to mount if someone is trying to open/create a file of any
+ * type under the mountpoint, wants to traverse through the mountpoint
+ * or wants to open the mounted directory.
+ *
+ * We don't want to mount if someone's just doing a stat and they've
+ * set AT_SYMLINK_NOFOLLOW - unless they're stat'ing a directory and
+ * appended a '/' to the name.
+ */
+ if (!(flags & LOOKUP_FOLLOW) &&
+ !(flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY |
+ LOOKUP_OPEN | LOOKUP_CREATE)))
+ return -EISDIR;
+
+ current->total_link_count++;
+ if (current->total_link_count >= 40)
+ return -ELOOP;
+
+ mnt = path->dentry->d_op->d_automount(path);
+ if (IS_ERR(mnt)) {
+ /*
+ * The filesystem is allowed to return -EISDIR here to indicate
+ * it doesn't want to automount. For instance, autofs would do
+ * this so that its userspace daemon can mount on this dentry.
+ *
+ * However, we can only permit this if it's a terminal point in
+ * the path being looked up; if it wasn't then the remainder of
+ * the path is inaccessible and we should say so.
+ */
+ if (PTR_ERR(mnt) == -EISDIR && (flags & LOOKUP_CONTINUE))
+ return -EREMOTE;
+ return PTR_ERR(mnt);
+ }
+
+ if (!mnt) /* mount collision */
+ return 0;
+
+ /* The new mount record should have at least 2 refs to prevent it being
+ * expired before we get a chance to add it
+ */
+ BUG_ON(mnt_get_count(mnt) < 2);
+
+ if (mnt->mnt_sb == path->mnt->mnt_sb &&
+ mnt->mnt_root == path->dentry) {
+ mnt_clear_expiry(mnt);
+ mntput(mnt);
+ mntput(mnt);
+ return -ELOOP;
+ }
+
+ /* We need to add the mountpoint to the parent. The filesystem may
+ * have placed it on an expiry list, and so we need to make sure it
+ * won't be expired under us if do_add_mount() fails (do_add_mount()
+ * will eat a reference unconditionally).
+ */
+ mntget(mnt);
+ err = do_add_mount(mnt, path, path->mnt->mnt_flags | MNT_SHRINKABLE);
+ switch (err) {
+ case -EBUSY:
+ /* Someone else made a mount here whilst we were busy */
+ err = 0;
+ default:
+ mnt_clear_expiry(mnt);
+ mntput(mnt);
+ mntput(mnt);
+ return err;
+ case 0:
+ mntput(mnt);
dput(path->dentry);
- if (res)
+ if (*need_mntput)
mntput(path->mnt);
+ path->mnt = mnt;
+ path->dentry = dget(mnt->mnt_root);
+ *need_mntput = true;
+ return 0;
+ }
+}
+
+/*
+ * Handle a dentry that is managed in some way.
+ * - Flagged for transit management (autofs)
+ * - Flagged as mountpoint
+ * - Flagged as automount point
+ *
+ * This may only be called in refwalk mode.
+ *
+ * Serialization is taken care of in namespace.c
+ */
+static int follow_managed(struct path *path, unsigned flags)
+{
+ unsigned managed;
+ bool need_mntput = false;
+ int ret;
+
+ /* Given that we're not holding a lock here, we retain the value in a
+ * local variable for each dentry as we look at it so that we don't see
+ * the components of that value change under us */
+ while (managed = ACCESS_ONCE(path->dentry->d_flags),
+ managed &= DCACHE_MANAGED_DENTRY,
+ unlikely(managed != 0)) {
+ /* Allow the filesystem to manage the transit without i_mutex
+ * being held. */
+ if (managed & DCACHE_MANAGE_TRANSIT) {
+ BUG_ON(!path->dentry->d_op);
+ BUG_ON(!path->dentry->d_op->d_manage);
+ ret = path->dentry->d_op->d_manage(path->dentry,
+ false, false);
+ if (ret < 0)
+ return ret == -EISDIR ? 0 : ret;
+ }
+
+ /* Transit to a mounted filesystem. */
+ if (managed & DCACHE_MOUNTED) {
+ struct vfsmount *mounted = lookup_mnt(path);
+ if (mounted) {
+ dput(path->dentry);
+ if (need_mntput)
+ mntput(path->mnt);
+ path->mnt = mounted;
+ path->dentry = dget(mounted->mnt_root);
+ need_mntput = true;
+ continue;
+ }
+
+ /* Something is mounted on this dentry in another
+ * namespace and/or whatever was mounted there in this
+ * namespace got unmounted before we managed to get the
+ * vfsmount_lock */
+ }
+
+ /* Handle an automount point */
+ if (managed & DCACHE_NEED_AUTOMOUNT) {
+ ret = follow_automount(path, flags, &need_mntput);
+ if (ret < 0)
+ return ret == -EISDIR ? 0 : ret;
+ continue;
+ }
+
+ /* We didn't change the current path point */
+ break;
+ }
+ return 0;
+}
+
+int follow_down_one(struct path *path)
+{
+ struct vfsmount *mounted;
+
+ mounted = lookup_mnt(path);
+ if (mounted) {
+ dput(path->dentry);
+ mntput(path->mnt);
path->mnt = mounted;
path->dentry = dget(mounted->mnt_root);
- res = 1;
+ return 1;
}
- return res;
+ return 0;
}
-static void follow_mount(struct path *path)
+/*
+ * Skip to top of mountpoint pile in rcuwalk mode. We abort the rcu-walk if we
+ * meet a managed dentry and we're not walking to "..". True is returned to
+ * continue, false to abort.
+ */
+static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
+ struct inode **inode, bool reverse_transit)
{
while (d_mountpoint(path->dentry)) {
- struct vfsmount *mounted = lookup_mnt(path);
+ struct vfsmount *mounted;
+ if (unlikely(path->dentry->d_flags & DCACHE_MANAGE_TRANSIT) &&
+ !reverse_transit &&
+ path->dentry->d_op->d_manage(path->dentry, false, true) < 0)
+ return false;
+ mounted = __lookup_mnt(path->mnt, path->dentry, 1);
if (!mounted)
break;
- dput(path->dentry);
- mntput(path->mnt);
path->mnt = mounted;
- path->dentry = dget(mounted->mnt_root);
+ path->dentry = mounted->mnt_root;
+ nd->seq = read_seqcount_begin(&path->dentry->d_seq);
+ *inode = path->dentry->d_inode;
}
+
+ if (unlikely(path->dentry->d_flags & DCACHE_NEED_AUTOMOUNT))
+ return reverse_transit;
+ return true;
}
-/* no need for dcache_lock, as serialization is taken care in
- * namespace.c
+static int follow_dotdot_rcu(struct nameidata *nd)
+{
+ struct inode *inode = nd->inode;
+
+ set_root_rcu(nd);
+
+ while (1) {
+ if (nd->path.dentry == nd->root.dentry &&
+ nd->path.mnt == nd->root.mnt) {
+ break;
+ }
+ if (nd->path.dentry != nd->path.mnt->mnt_root) {
+ struct dentry *old = nd->path.dentry;
+ struct dentry *parent = old->d_parent;
+ unsigned seq;
+
+ seq = read_seqcount_begin(&parent->d_seq);
+ if (read_seqcount_retry(&old->d_seq, nd->seq))
+ return -ECHILD;
+ inode = parent->d_inode;
+ nd->path.dentry = parent;
+ nd->seq = seq;
+ break;
+ }
+ if (!follow_up_rcu(&nd->path))
+ break;
+ nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
+ inode = nd->path.dentry->d_inode;
+ }
+ __follow_mount_rcu(nd, &nd->path, &inode, true);
+ nd->inode = inode;
+
+ return 0;
+}
+
+/*
+ * Follow down to the covering mount currently visible to userspace. At each
+ * point, the filesystem owning that dentry may be queried as to whether the
+ * caller is permitted to proceed or not.
+ *
+ * Care must be taken as namespace_sem may be held (indicated by mounting_here
+ * being true).
*/
-int follow_down(struct path *path)
+int follow_down(struct path *path, bool mounting_here)
{
- struct vfsmount *mounted;
+ unsigned managed;
+ int ret;
- mounted = lookup_mnt(path);
- if (mounted) {
+ while (managed = ACCESS_ONCE(path->dentry->d_flags),
+ unlikely(managed & DCACHE_MANAGED_DENTRY)) {
+ /* Allow the filesystem to manage the transit without i_mutex
+ * being held.
+ *
+ * We indicate to the filesystem if someone is trying to mount
+ * something here. This gives autofs the chance to deny anyone
+ * other than its daemon the right to mount on its
+ * superstructure.
+ *
+ * The filesystem may sleep at this point.
+ */
+ if (managed & DCACHE_MANAGE_TRANSIT) {
+ BUG_ON(!path->dentry->d_op);
+ BUG_ON(!path->dentry->d_op->d_manage);
+ ret = path->dentry->d_op->d_manage(
+ path->dentry, mounting_here, false);
+ if (ret < 0)
+ return ret == -EISDIR ? 0 : ret;
+ }
+
+ /* Transit to a mounted filesystem. */
+ if (managed & DCACHE_MOUNTED) {
+ struct vfsmount *mounted = lookup_mnt(path);
+ if (!mounted)
+ break;
+ dput(path->dentry);
+ mntput(path->mnt);
+ path->mnt = mounted;
+ path->dentry = dget(mounted->mnt_root);
+ continue;
+ }
+
+ /* Don't handle automount points here */
+ break;
+ }
+ return 0;
+}
+
+/*
+ * Skip to top of mountpoint pile in refwalk mode for follow_dotdot()
+ */
+static void follow_mount(struct path *path)
+{
+ while (d_mountpoint(path->dentry)) {
+ struct vfsmount *mounted = lookup_mnt(path);
+ if (!mounted)
+ break;
dput(path->dentry);
mntput(path->mnt);
path->mnt = mounted;
path->dentry = dget(mounted->mnt_root);
- return 1;
}
- return 0;
}
-static __always_inline void follow_dotdot(struct nameidata *nd)
+static void follow_dotdot(struct nameidata *nd)
{
set_root(nd);
break;
}
follow_mount(&nd->path);
+ nd->inode = nd->path.dentry->d_inode;
}
/*
* It _is_ time-critical.
*/
static int do_lookup(struct nameidata *nd, struct qstr *name,
- struct path *path)
+ struct path *path, struct inode **inode)
{
struct vfsmount *mnt = nd->path.mnt;
- struct dentry *dentry, *parent;
+ struct dentry *dentry, *parent = nd->path.dentry;
struct inode *dir;
+ int err;
+
/*
* See if the low-level filesystem might want
* to use its own hash..
*/
- if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) {
- int err = nd->path.dentry->d_op->d_hash(nd->path.dentry,
- nd->path.dentry->d_inode, name);
+ if (unlikely(parent->d_flags & DCACHE_OP_HASH)) {
+ err = parent->d_op->d_hash(parent, nd->inode, name);
if (err < 0)
return err;
}
* 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 (nd->flags & LOOKUP_RCU) {
+ unsigned seq;
+
+ *inode = nd->inode;
+ dentry = __d_lookup_rcu(parent, name, &seq, inode);
+ if (!dentry) {
+ if (nameidata_drop_rcu(nd))
+ return -ECHILD;
+ goto need_lookup;
+ }
+ /* Memory barrier in read_seqcount_begin of child is enough */
+ if (__read_seqcount_retry(&parent->d_seq, nd->seq))
+ return -ECHILD;
+
+ nd->seq = seq;
+ if (dentry->d_flags & DCACHE_OP_REVALIDATE)
+ goto need_revalidate;
+done2:
+ path->mnt = mnt;
+ path->dentry = dentry;
+ if (likely(__follow_mount_rcu(nd, path, inode, false)))
+ return 0;
+ if (nameidata_drop_rcu(nd))
+ return -ECHILD;
+ /* fallthru */
+ }
+ dentry = __d_lookup(parent, name);
if (!dentry)
goto need_lookup;
found:
- if (dentry->d_op && dentry->d_op->d_revalidate)
+ if (dentry->d_flags & DCACHE_OP_REVALIDATE)
goto need_revalidate;
done:
path->mnt = mnt;
path->dentry = dentry;
- __follow_mount(path);
+ err = follow_managed(path, nd->flags);
+ if (unlikely(err < 0))
+ return err;
+ *inode = path->dentry->d_inode;
return 0;
need_lookup:
- parent = nd->path.dentry;
dir = parent->d_inode;
+ BUG_ON(nd->inode != dir);
mutex_lock(&dir->i_mutex);
/*
goto need_lookup;
if (IS_ERR(dentry))
goto fail;
+ if (nd->flags & LOOKUP_RCU)
+ goto done2;
goto done;
fail:
return PTR_ERR(dentry);
}
-/*
- * This is a temporary kludge to deal with "automount" symlinks; proper
- * solution is to trigger them on follow_mount(), so that do_lookup()
- * would DTRT. To be killed before 2.6.34-final.
- */
-static inline int follow_on_final(struct inode *inode, unsigned lookup_flags)
-{
- return inode && unlikely(inode->i_op->follow_link) &&
- ((lookup_flags & LOOKUP_FOLLOW) || S_ISDIR(inode->i_mode));
-}
-
/*
* Name resolution.
* This is the basic name resolution function, turning a pathname into
static int link_path_walk(const char *name, struct nameidata *nd)
{
struct path next;
- struct inode *inode;
int err;
unsigned int lookup_flags = nd->flags;
if (!*name)
goto return_reval;
- inode = nd->path.dentry->d_inode;
if (nd->depth)
lookup_flags = LOOKUP_FOLLOW | (nd->flags & LOOKUP_CONTINUE);
/* At this point we know we have a real path component. */
for(;;) {
+ struct inode *inode;
unsigned long hash;
struct qstr this;
unsigned int c;
nd->flags |= LOOKUP_CONTINUE;
- err = exec_permission(inode);
+ if (nd->flags & LOOKUP_RCU) {
+ err = exec_permission(nd->inode, IPERM_FLAG_RCU);
+ if (err == -ECHILD) {
+ if (nameidata_drop_rcu(nd))
+ return -ECHILD;
+ goto exec_again;
+ }
+ } else {
+exec_again:
+ err = exec_permission(nd->inode, 0);
+ }
if (err)
break;
if (this.name[0] == '.') switch (this.len) {
default:
break;
- case 2:
+ case 2:
if (this.name[1] != '.')
break;
- follow_dotdot(nd);
- inode = nd->path.dentry->d_inode;
+ if (nd->flags & LOOKUP_RCU) {
+ if (follow_dotdot_rcu(nd))
+ return -ECHILD;
+ } else
+ follow_dotdot(nd);
/* fallthrough */
case 1:
continue;
}
/* This does the actual lookups.. */
- err = do_lookup(nd, &this, &next);
+ err = do_lookup(nd, &this, &next, &inode);
if (err)
break;
-
err = -ENOENT;
- inode = next.dentry->d_inode;
if (!inode)
goto out_dput;
if (inode->i_op->follow_link) {
+ /* We commonly drop rcu-walk here */
+ if (nameidata_dentry_drop_rcu_maybe(nd, next.dentry))
+ return -ECHILD;
+ BUG_ON(inode != next.dentry->d_inode);
err = do_follow_link(&next, nd);
if (err)
goto return_err;
+ nd->inode = nd->path.dentry->d_inode;
err = -ENOENT;
- inode = nd->path.dentry->d_inode;
- if (!inode)
+ if (!nd->inode)
break;
- } else
+ } else {
path_to_nameidata(&next, nd);
+ nd->inode = inode;
+ }
err = -ENOTDIR;
- if (!inode->i_op->lookup)
+ if (!nd->inode->i_op->lookup)
break;
continue;
/* here ends the main loop */
if (this.name[0] == '.') switch (this.len) {
default:
break;
- case 2:
+ case 2:
if (this.name[1] != '.')
break;
- follow_dotdot(nd);
- inode = nd->path.dentry->d_inode;
+ if (nd->flags & LOOKUP_RCU) {
+ if (follow_dotdot_rcu(nd))
+ return -ECHILD;
+ } else
+ follow_dotdot(nd);
/* fallthrough */
case 1:
goto return_reval;
}
- err = do_lookup(nd, &this, &next);
+ err = do_lookup(nd, &this, &next, &inode);
if (err)
break;
- inode = next.dentry->d_inode;
- if (follow_on_final(inode, lookup_flags)) {
+ if (inode && unlikely(inode->i_op->follow_link) &&
+ (lookup_flags & LOOKUP_FOLLOW)) {
+ if (nameidata_dentry_drop_rcu_maybe(nd, next.dentry))
+ return -ECHILD;
+ BUG_ON(inode != next.dentry->d_inode);
err = do_follow_link(&next, nd);
if (err)
goto return_err;
- inode = nd->path.dentry->d_inode;
- } else
+ nd->inode = nd->path.dentry->d_inode;
+ } else {
path_to_nameidata(&next, nd);
+ nd->inode = inode;
+ }
err = -ENOENT;
- if (!inode)
+ if (!nd->inode)
break;
if (lookup_flags & LOOKUP_DIRECTORY) {
err = -ENOTDIR;
- if (!inode->i_op->lookup)
+ if (!nd->inode->i_op->lookup)
break;
}
goto return_base;
* We bypassed the ordinary revalidation routines.
* We may need to check the cached dentry for staleness.
*/
- if (nd->path.dentry && nd->path.dentry->d_sb &&
- (nd->path.dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)) {
- err = -ESTALE;
+ if (need_reval_dot(nd->path.dentry)) {
/* Note: we do not d_invalidate() */
- if (!nd->path.dentry->d_op->d_revalidate(
- nd->path.dentry, nd))
+ err = d_revalidate(nd->path.dentry, nd);
+ if (!err)
+ err = -ESTALE;
+ if (err < 0)
break;
}
return_base:
+ if (nameidata_drop_rcu_last_maybe(nd))
+ return -ECHILD;
return 0;
out_dput:
- path_put_conditional(&next, nd);
+ if (!(nd->flags & LOOKUP_RCU))
+ path_put_conditional(&next, nd);
break;
}
- path_put(&nd->path);
+ if (!(nd->flags & LOOKUP_RCU))
+ path_put(&nd->path);
return_err:
return err;
}
+static inline int path_walk_rcu(const char *name, struct nameidata *nd)
+{
+ current->total_link_count = 0;
+
+ return link_path_walk(name, nd);
+}
+
+static inline int path_walk_simple(const char *name, struct nameidata *nd)
+{
+ current->total_link_count = 0;
+
+ return link_path_walk(name, nd);
+}
+
static int path_walk(const char *name, struct nameidata *nd)
{
struct path save = nd->path;
return result;
}
+static void path_finish_rcu(struct nameidata *nd)
+{
+ if (nd->flags & LOOKUP_RCU) {
+ /* RCU dangling. Cancel it. */
+ nd->flags &= ~LOOKUP_RCU;
+ nd->root.mnt = NULL;
+ rcu_read_unlock();
+ br_read_unlock(vfsmount_lock);
+ }
+ if (nd->file)
+ fput(nd->file);
+}
+
+static int path_init_rcu(int dfd, const char *name, unsigned int flags, struct nameidata *nd)
+{
+ int retval = 0;
+ int fput_needed;
+ struct file *file;
+
+ nd->last_type = LAST_ROOT; /* if there are only slashes... */
+ nd->flags = flags | LOOKUP_RCU;
+ nd->depth = 0;
+ nd->root.mnt = NULL;
+ nd->file = NULL;
+
+ if (*name=='/') {
+ struct fs_struct *fs = current->fs;
+ unsigned seq;
+
+ br_read_lock(vfsmount_lock);
+ rcu_read_lock();
+
+ do {
+ seq = read_seqcount_begin(&fs->seq);
+ nd->root = fs->root;
+ nd->path = nd->root;
+ nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
+ } while (read_seqcount_retry(&fs->seq, seq));
+
+ } else if (dfd == AT_FDCWD) {
+ struct fs_struct *fs = current->fs;
+ unsigned seq;
+
+ br_read_lock(vfsmount_lock);
+ rcu_read_lock();
+
+ do {
+ seq = read_seqcount_begin(&fs->seq);
+ nd->path = fs->pwd;
+ nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
+ } while (read_seqcount_retry(&fs->seq, seq));
+
+ } else {
+ struct dentry *dentry;
+
+ file = fget_light(dfd, &fput_needed);
+ retval = -EBADF;
+ if (!file)
+ goto out_fail;
+
+ dentry = file->f_path.dentry;
+
+ retval = -ENOTDIR;
+ if (!S_ISDIR(dentry->d_inode->i_mode))
+ goto fput_fail;
+
+ retval = file_permission(file, MAY_EXEC);
+ if (retval)
+ goto fput_fail;
+
+ nd->path = file->f_path;
+ if (fput_needed)
+ nd->file = file;
+
+ nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
+ br_read_lock(vfsmount_lock);
+ rcu_read_lock();
+ }
+ nd->inode = nd->path.dentry->d_inode;
+ return 0;
+
+fput_fail:
+ fput_light(file, fput_needed);
+out_fail:
+ return retval;
+}
+
static int path_init(int dfd, const char *name, unsigned int flags, struct nameidata *nd)
{
int retval = 0;
fput_light(file, fput_needed);
}
+ nd->inode = nd->path.dentry->d_inode;
return 0;
fput_fail:
static int do_path_lookup(int dfd, const char *name,
unsigned int flags, struct nameidata *nd)
{
- int retval = path_init(dfd, name, flags, nd);
- if (!retval)
- retval = path_walk(name, nd);
- if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry &&
- nd->path.dentry->d_inode))
- audit_inode(name, nd->path.dentry);
+ int retval;
+
+ /*
+ * Path walking is largely split up into 2 different synchronisation
+ * schemes, rcu-walk and ref-walk (explained in
+ * Documentation/filesystems/path-lookup.txt). These share much of the
+ * path walk code, but some things particularly setup, cleanup, and
+ * following mounts are sufficiently divergent that functions are
+ * duplicated. Typically there is a function foo(), and its RCU
+ * analogue, foo_rcu().
+ *
+ * -ECHILD is the error number of choice (just to avoid clashes) that
+ * is returned if some aspect of an rcu-walk fails. Such an error must
+ * be handled by restarting a traditional ref-walk (which will always
+ * be able to complete).
+ */
+ retval = path_init_rcu(dfd, name, flags, nd);
+ if (unlikely(retval))
+ return retval;
+ retval = path_walk_rcu(name, nd);
+ path_finish_rcu(nd);
if (nd->root.mnt) {
path_put(&nd->root);
nd->root.mnt = NULL;
}
+
+ if (unlikely(retval == -ECHILD || retval == -ESTALE)) {
+ /* slower, locked walk */
+ if (retval == -ESTALE)
+ flags |= LOOKUP_REVAL;
+ retval = path_init(dfd, name, flags, nd);
+ if (unlikely(retval))
+ return retval;
+ retval = path_walk(name, nd);
+ if (nd->root.mnt) {
+ path_put(&nd->root);
+ nd->root.mnt = NULL;
+ }
+ }
+
+ if (likely(!retval)) {
+ if (unlikely(!audit_dummy_context())) {
+ if (nd->path.dentry && nd->inode)
+ audit_inode(name, nd->path.dentry);
+ }
+ }
+
return retval;
}
path_get(&nd->path);
nd->root = nd->path;
path_get(&nd->root);
+ nd->inode = nd->path.dentry->d_inode;
retval = path_walk(name, nd);
if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry &&
- nd->path.dentry->d_inode))
+ nd->inode))
audit_inode(name, nd->path.dentry);
path_put(&nd->root);
struct dentry *dentry;
int err;
- err = exec_permission(inode);
+ err = exec_permission(inode, 0);
if (err)
return ERR_PTR(err);
* See if the low-level filesystem might want
* to use its own hash..
*/
- if (base->d_op && base->d_op->d_hash) {
+ if (base->d_flags & DCACHE_OP_HASH) {
err = base->d_op->d_hash(base, inode, name);
dentry = ERR_PTR(err);
if (err < 0)
*/
dentry = d_lookup(base, name);
- if (dentry && dentry->d_op && dentry->d_op->d_revalidate)
+ if (dentry && (dentry->d_flags & DCACHE_OP_REVALIDATE))
dentry = do_revalidate(dentry, nd);
if (!dentry)
return break_lease(inode, flag);
}
-static int handle_truncate(struct path *path)
+static int handle_truncate(struct file *filp)
{
+ struct path *path = &filp->f_path;
struct inode *inode = path->dentry->d_inode;
int error = get_write_access(inode);
if (error)
if (!error) {
error = do_truncate(path->dentry, 0,
ATTR_MTIME|ATTR_CTIME|ATTR_OPEN,
- NULL);
+ filp);
}
put_write_access(inode);
return error;
mutex_unlock(&dir->d_inode->i_mutex);
dput(nd->path.dentry);
nd->path.dentry = path->dentry;
+
if (error)
return error;
/* Don't check for write permission, don't truncate */
}
if (!IS_ERR(filp)) {
if (will_truncate) {
- error = handle_truncate(&nd->path);
+ error = handle_truncate(filp);
if (error) {
fput(filp);
filp = ERR_PTR(error);
return ERR_PTR(error);
}
+/*
+ * Handle O_CREAT case for do_filp_open
+ */
static struct file *do_last(struct nameidata *nd, struct path *path,
int open_flag, int acc_mode,
int mode, const char *pathname)
follow_dotdot(nd);
dir = nd->path.dentry;
case LAST_DOT:
- if (nd->path.mnt->mnt_sb->s_type->fs_flags & FS_REVAL_DOT) {
- if (!dir->d_op->d_revalidate(dir, nd)) {
- error = -ESTALE;
+ if (need_reval_dot(dir)) {
+ int status = d_revalidate(nd->path.dentry, nd);
+ if (!status)
+ status = -ESTALE;
+ if (status < 0) {
+ error = status;
goto exit;
}
}
/* fallthrough */
case LAST_ROOT:
- if (open_flag & O_CREAT)
- goto exit;
- /* fallthrough */
+ goto exit;
case LAST_BIND:
audit_inode(pathname, dir);
goto ok;
}
/* trailing slashes? */
- if (nd->last.name[nd->last.len]) {
- if (open_flag & O_CREAT)
- goto exit;
- nd->flags |= LOOKUP_DIRECTORY | LOOKUP_FOLLOW;
- }
-
- /* just plain open? */
- if (!(open_flag & O_CREAT)) {
- error = do_lookup(nd, &nd->last, path);
- if (error)
- goto exit;
- error = -ENOENT;
- if (!path->dentry->d_inode)
- goto exit_dput;
- if (path->dentry->d_inode->i_op->follow_link)
- return NULL;
- error = -ENOTDIR;
- if (nd->flags & LOOKUP_DIRECTORY) {
- if (!path->dentry->d_inode->i_op->lookup)
- goto exit_dput;
- }
- path_to_nameidata(path, nd);
- audit_inode(pathname, nd->path.dentry);
- goto ok;
- }
+ if (nd->last.name[nd->last.len])
+ goto exit;
- /* OK, it's O_CREAT */
mutex_lock(&dir->d_inode->i_mutex);
path->dentry = lookup_hash(nd);
if (open_flag & O_EXCL)
goto exit_dput;
- if (__follow_mount(path)) {
- error = -ELOOP;
- if (open_flag & O_NOFOLLOW)
- goto exit_dput;
- }
+ error = follow_managed(path, nd->flags);
+ if (error < 0)
+ goto exit_dput;
error = -ENOENT;
if (!path->dentry->d_inode)
return NULL;
path_to_nameidata(path, nd);
+ nd->inode = path->dentry->d_inode;
error = -EISDIR;
- if (S_ISDIR(path->dentry->d_inode->i_mode))
+ if (S_ISDIR(nd->inode->i_mode))
goto exit;
ok:
filp = finish_open(nd, open_flag, acc_mode);
struct path path;
int count = 0;
int flag = open_to_namei_flags(open_flag);
- int force_reval = 0;
+ int flags;
if (!(open_flag & O_CREAT))
mode = 0;
if (open_flag & O_APPEND)
acc_mode |= MAY_APPEND;
- /* find the parent */
-reval:
- error = path_init(dfd, pathname, LOOKUP_PARENT, &nd);
+ flags = LOOKUP_OPEN;
+ if (open_flag & O_CREAT) {
+ flags |= LOOKUP_CREATE;
+ if (open_flag & O_EXCL)
+ flags |= LOOKUP_EXCL;
+ }
+ if (open_flag & O_DIRECTORY)
+ flags |= LOOKUP_DIRECTORY;
+ if (!(open_flag & O_NOFOLLOW))
+ flags |= LOOKUP_FOLLOW;
+
+ filp = get_empty_filp();
+ if (!filp)
+ return ERR_PTR(-ENFILE);
+
+ filp->f_flags = open_flag;
+ nd.intent.open.file = filp;
+ nd.intent.open.flags = flag;
+ nd.intent.open.create_mode = mode;
+
+ if (open_flag & O_CREAT)
+ goto creat;
+
+ /* !O_CREAT, simple open */
+ error = do_path_lookup(dfd, pathname, flags, &nd);
+ if (unlikely(error))
+ goto out_filp;
+ error = -ELOOP;
+ if (!(nd.flags & LOOKUP_FOLLOW)) {
+ if (nd.inode->i_op->follow_link)
+ goto out_path;
+ }
+ error = -ENOTDIR;
+ if (nd.flags & LOOKUP_DIRECTORY) {
+ if (!nd.inode->i_op->lookup)
+ goto out_path;
+ }
+ audit_inode(pathname, nd.path.dentry);
+ filp = finish_open(&nd, open_flag, acc_mode);
+ return filp;
+
+creat:
+ /* OK, have to create the file. Find the parent. */
+ error = path_init_rcu(dfd, pathname,
+ LOOKUP_PARENT | (flags & LOOKUP_REVAL), &nd);
if (error)
- return ERR_PTR(error);
- if (force_reval)
- nd.flags |= LOOKUP_REVAL;
+ goto out_filp;
+ error = path_walk_rcu(pathname, &nd);
+ path_finish_rcu(&nd);
+ if (unlikely(error == -ECHILD || error == -ESTALE)) {
+ /* slower, locked walk */
+ if (error == -ESTALE) {
+reval:
+ flags |= LOOKUP_REVAL;
+ }
+ error = path_init(dfd, pathname,
+ LOOKUP_PARENT | (flags & LOOKUP_REVAL), &nd);
+ if (error)
+ goto out_filp;
- current->total_link_count = 0;
- error = link_path_walk(pathname, &nd);
- if (error) {
- filp = ERR_PTR(error);
- goto out;
+ error = path_walk_simple(pathname, &nd);
}
- if (unlikely(!audit_dummy_context()) && (open_flag & O_CREAT))
+ if (unlikely(error))
+ goto out_filp;
+ if (unlikely(!audit_dummy_context()))
audit_inode(pathname, nd.path.dentry);
/*
* We have the parent and last component.
*/
-
- error = -ENFILE;
- filp = get_empty_filp();
- if (filp == NULL)
- goto exit_parent;
- nd.intent.open.file = filp;
- filp->f_flags = open_flag;
- nd.intent.open.flags = flag;
- nd.intent.open.create_mode = mode;
- nd.flags &= ~LOOKUP_PARENT;
- nd.flags |= LOOKUP_OPEN;
- if (open_flag & O_CREAT) {
- nd.flags |= LOOKUP_CREATE;
- if (open_flag & O_EXCL)
- nd.flags |= LOOKUP_EXCL;
- }
- if (open_flag & O_DIRECTORY)
- nd.flags |= LOOKUP_DIRECTORY;
- if (!(open_flag & O_NOFOLLOW))
- nd.flags |= LOOKUP_FOLLOW;
+ nd.flags = flags;
filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname);
while (unlikely(!filp)) { /* trailing symlink */
- struct path holder;
- struct inode *inode = path.dentry->d_inode;
+ struct path link = path;
+ struct inode *linki = link.dentry->d_inode;
void *cookie;
error = -ELOOP;
- /* S_ISDIR part is a temporary automount kludge */
- if (!(nd.flags & LOOKUP_FOLLOW) && !S_ISDIR(inode->i_mode))
+ if (!(nd.flags & LOOKUP_FOLLOW))
goto exit_dput;
if (count++ == 32)
goto exit_dput;
* just set LAST_BIND.
*/
nd.flags |= LOOKUP_PARENT;
- error = security_inode_follow_link(path.dentry, &nd);
+ error = security_inode_follow_link(link.dentry, &nd);
if (error)
goto exit_dput;
- error = __do_follow_link(&path, &nd, &cookie);
+ error = __do_follow_link(&link, &nd, &cookie);
if (unlikely(error)) {
+ if (!IS_ERR(cookie) && linki->i_op->put_link)
+ linki->i_op->put_link(link.dentry, &nd, cookie);
/* nd.path had been dropped */
- if (!IS_ERR(cookie) && inode->i_op->put_link)
- inode->i_op->put_link(path.dentry, &nd, cookie);
- path_put(&path);
- release_open_intent(&nd);
- filp = ERR_PTR(error);
- goto out;
+ nd.path = link;
+ goto out_path;
}
- holder = path;
nd.flags &= ~LOOKUP_PARENT;
filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname);
- if (inode->i_op->put_link)
- inode->i_op->put_link(holder.dentry, &nd, cookie);
- path_put(&holder);
+ if (linki->i_op->put_link)
+ linki->i_op->put_link(link.dentry, &nd, cookie);
+ path_put(&link);
}
out:
if (nd.root.mnt)
path_put(&nd.root);
- if (filp == ERR_PTR(-ESTALE) && !force_reval) {
- force_reval = 1;
+ if (filp == ERR_PTR(-ESTALE) && !(flags & LOOKUP_REVAL))
goto reval;
- }
return filp;
exit_dput:
path_put_conditional(&path, &nd);
+out_path:
+ path_put(&nd.path);
+out_filp:
if (!IS_ERR(nd.intent.open.file))
release_open_intent(&nd);
-exit_parent:
- path_put(&nd.path);
filp = ERR_PTR(error);
goto out;
}
{
dget(dentry);
shrink_dcache_parent(dentry);
- spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
if (dentry->d_count == 2)
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
}
int vfs_rmdir(struct inode *dir, struct dentry *dentry)
};
EXPORT_SYMBOL(user_path_at);
+EXPORT_SYMBOL(follow_down_one);
EXPORT_SYMBOL(follow_down);
EXPORT_SYMBOL(follow_up);
EXPORT_SYMBOL(get_write_access); /* binfmt_aout */