* - return -EISDIR to tell follow_managed() to stop and return the path we
* were called with.
*/
-static int follow_automount(struct path *path, struct nameidata *nd,
- bool *need_mntput)
+static int follow_automount(struct path *path, int *count, unsigned lookup_flags)
{
- struct vfsmount *mnt;
- int err;
-
- if (!path->dentry->d_op || !path->dentry->d_op->d_automount)
- return -EREMOTE;
+ struct dentry *dentry = path->dentry;
/* We don't want to mount if someone's just doing a stat -
* unless they're stat'ing a directory and appended a '/' to
* as being automount points. These will need the attentions
* of the daemon to instantiate them before they can be used.
*/
- if (!(nd->flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |
+ if (!(lookup_flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |
LOOKUP_OPEN | LOOKUP_CREATE | LOOKUP_AUTOMOUNT)) &&
- path->dentry->d_inode)
+ dentry->d_inode)
return -EISDIR;
- nd->total_link_count++;
- if (nd->total_link_count >= 40)
+ if (count && (*count)++ >= MAXSYMLINKS)
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 && (nd->flags & LOOKUP_PARENT))
- return -EREMOTE;
- return PTR_ERR(mnt);
- }
-
- if (!mnt) /* mount collision */
- return 0;
-
- if (!*need_mntput) {
- /* lock_mount() may release path->mnt on error */
- mntget(path->mnt);
- *need_mntput = true;
- }
- err = finish_automount(mnt, path);
-
- switch (err) {
- case -EBUSY:
- /* Someone else made a mount here whilst we were busy */
- return 0;
- case 0:
- path_put(path);
- path->mnt = mnt;
- path->dentry = dget(mnt->mnt_root);
- return 0;
- default:
- return err;
- }
-
+ return finish_automount(dentry->d_op->d_automount(path), path);
}
/*
/* Handle an automount point */
if (flags & DCACHE_NEED_AUTOMOUNT) {
- ret = follow_automount(path, nd, &need_mntput);
+ ret = follow_automount(path, &nd->total_link_count,
+ nd->flags);
if (ret < 0)
break;
continue;
!(path->dentry->d_flags & DCACHE_NEED_AUTOMOUNT);
}
+static inline int handle_mounts(struct nameidata *nd, struct dentry *dentry,
+ struct path *path, struct inode **inode,
+ unsigned int *seqp)
+{
+ int ret;
+
+ path->mnt = nd->path.mnt;
+ path->dentry = dentry;
+ if (nd->flags & LOOKUP_RCU) {
+ unsigned int seq = *seqp;
+ if (unlikely(!*inode))
+ return -ENOENT;
+ if (likely(__follow_mount_rcu(nd, path, inode, seqp)))
+ return 1;
+ if (unlazy_child(nd, dentry, seq))
+ return -ECHILD;
+ // *path might've been clobbered by __follow_mount_rcu()
+ path->mnt = nd->path.mnt;
+ path->dentry = dentry;
+ }
+ ret = follow_managed(path, nd);
+ if (likely(ret >= 0)) {
+ *inode = d_backing_inode(path->dentry);
+ *seqp = 0; /* out of RCU mode, so the value doesn't matter */
+ }
+ return ret;
+}
+
static int follow_dotdot_rcu(struct nameidata *nd)
{
struct inode *inode = nd->inode;
return dentry;
}
-static int lookup_fast(struct nameidata *nd,
- struct path *path, struct inode **inode,
- unsigned *seqp)
+static struct dentry *lookup_fast(struct nameidata *nd,
+ struct inode **inode,
+ unsigned *seqp)
{
- struct vfsmount *mnt = nd->path.mnt;
struct dentry *dentry, *parent = nd->path.dentry;
int status = 1;
- int err;
/*
* Rename seqlock is not required here because in the off chance
*/
if (nd->flags & LOOKUP_RCU) {
unsigned seq;
- bool negative;
dentry = __d_lookup_rcu(parent, &nd->last, &seq);
if (unlikely(!dentry)) {
if (unlazy_walk(nd))
- return -ECHILD;
- return 0;
+ return ERR_PTR(-ECHILD);
+ return NULL;
}
/*
* the dentry name information from lookup.
*/
*inode = d_backing_inode(dentry);
- negative = d_is_negative(dentry);
if (unlikely(read_seqcount_retry(&dentry->d_seq, seq)))
- return -ECHILD;
+ return ERR_PTR(-ECHILD);
/*
* This sequence count validates that the parent had no
* enough, we can use __read_seqcount_retry here.
*/
if (unlikely(__read_seqcount_retry(&parent->d_seq, nd->seq)))
- return -ECHILD;
+ return ERR_PTR(-ECHILD);
*seqp = seq;
status = d_revalidate(dentry, nd->flags);
- if (likely(status > 0)) {
- /*
- * Note: do negative dentry check after revalidation in
- * case that drops it.
- */
- if (unlikely(negative))
- return -ENOENT;
- path->mnt = mnt;
- path->dentry = dentry;
- if (likely(__follow_mount_rcu(nd, path, inode, seqp)))
- return 1;
- }
+ if (likely(status > 0))
+ return dentry;
if (unlazy_child(nd, dentry, seq))
- return -ECHILD;
+ return ERR_PTR(-ECHILD);
if (unlikely(status == -ECHILD))
/* we'd been told to redo it in non-rcu mode */
status = d_revalidate(dentry, nd->flags);
} else {
dentry = __d_lookup(parent, &nd->last);
if (unlikely(!dentry))
- return 0;
+ return NULL;
status = d_revalidate(dentry, nd->flags);
}
if (unlikely(status <= 0)) {
if (!status)
d_invalidate(dentry);
dput(dentry);
- return status;
+ return ERR_PTR(status);
}
-
- path->mnt = mnt;
- path->dentry = dentry;
- err = follow_managed(path, nd);
- if (likely(err > 0))
- *inode = d_backing_inode(path->dentry);
- return err;
+ return dentry;
}
/* Fast lookup failed, do it the slow way */
return 1;
}
-enum {WALK_FOLLOW = 1, WALK_MORE = 2};
+enum {WALK_FOLLOW = 1, WALK_MORE = 2, WALK_NOFOLLOW = 4};
/*
* Do we need to follow links? We _really_ want to be able
* so we keep a cache of "no, this doesn't need follow_link"
* for the common case.
*/
-static inline int step_into(struct nameidata *nd, struct path *path,
- int flags, struct inode *inode, unsigned seq)
+static int step_into(struct nameidata *nd, int flags,
+ struct dentry *dentry, struct inode *inode, unsigned seq)
{
- if (!(flags & WALK_MORE) && nd->depth)
- put_link(nd);
- if (likely(!d_is_symlink(path->dentry)) ||
- !(flags & WALK_FOLLOW || nd->flags & LOOKUP_FOLLOW)) {
+ struct path path;
+ int err = handle_mounts(nd, dentry, &path, &inode, &seq);
+
+ if (err < 0)
+ return err;
+ if (likely(!d_is_symlink(path.dentry)) ||
+ !((flags & WALK_FOLLOW) || (nd->flags & LOOKUP_FOLLOW)) ||
+ (flags & WALK_NOFOLLOW)) {
/* not a symlink or should not follow */
- path_to_nameidata(path, nd);
+ path_to_nameidata(&path, nd);
nd->inode = inode;
nd->seq = seq;
return 0;
}
/* make sure that d_is_symlink above matches inode */
if (nd->flags & LOOKUP_RCU) {
- if (read_seqcount_retry(&path->dentry->d_seq, seq))
+ if (read_seqcount_retry(&path.dentry->d_seq, seq))
return -ECHILD;
}
- return pick_link(nd, path, inode, seq);
+ return pick_link(nd, &path, inode, seq);
}
static int walk_component(struct nameidata *nd, int flags)
{
- struct path path;
+ struct dentry *dentry;
struct inode *inode;
unsigned seq;
int err;
* parent relationships.
*/
if (unlikely(nd->last_type != LAST_NORM)) {
- err = handle_dots(nd, nd->last_type);
if (!(flags & WALK_MORE) && nd->depth)
put_link(nd);
+ err = handle_dots(nd, nd->last_type);
return err;
}
- err = lookup_fast(nd, &path, &inode, &seq);
- if (unlikely(err <= 0)) {
- if (err < 0)
- return err;
- path.dentry = lookup_slow(&nd->last, nd->path.dentry,
- nd->flags);
- if (IS_ERR(path.dentry))
- return PTR_ERR(path.dentry);
-
- path.mnt = nd->path.mnt;
- err = follow_managed(&path, nd);
- if (unlikely(err < 0))
- return err;
-
- seq = 0; /* we are already out of RCU mode */
- inode = d_backing_inode(path.dentry);
+ dentry = lookup_fast(nd, &inode, &seq);
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
+ if (unlikely(!dentry)) {
+ dentry = lookup_slow(&nd->last, nd->path.dentry, nd->flags);
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
}
-
- return step_into(nd, &path, flags, inode, seq);
+ if (!(flags & WALK_MORE) && nd->depth)
+ put_link(nd);
+ return step_into(nd, flags, dentry, inode, seq);
}
/*
static int handle_lookup_down(struct nameidata *nd)
{
- struct path path = nd->path;
- struct inode *inode = nd->inode;
- unsigned seq = nd->seq;
- int err;
-
- if (nd->flags & LOOKUP_RCU) {
- /*
- * don't bother with unlazy_walk on failure - we are
- * at the very beginning of walk, so we lose nothing
- * if we simply redo everything in non-RCU mode
- */
- if (unlikely(!__follow_mount_rcu(nd, &path, &inode, &seq)))
- return -ECHILD;
- } else {
- dget(path.dentry);
- err = follow_managed(&path, nd);
- if (unlikely(err < 0))
- return err;
- inode = d_backing_inode(path.dentry);
- seq = 0;
- }
- path_to_nameidata(&path, nd);
- nd->inode = inode;
- nd->seq = seq;
- return 0;
+ if (!(nd->flags & LOOKUP_RCU))
+ dget(nd->path.dentry);
+ return step_into(nd, WALK_NOFOLLOW,
+ nd->path.dentry, nd->inode, nd->seq);
}
/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
*
* Returns an error code otherwise.
*/
-static int atomic_open(struct nameidata *nd, struct dentry *dentry,
- struct path *path, struct file *file,
- const struct open_flags *op,
- int open_flag, umode_t mode)
+static struct dentry *atomic_open(struct nameidata *nd, struct dentry *dentry,
+ struct file *file,
+ const struct open_flags *op,
+ int open_flag, umode_t mode)
{
struct dentry *const DENTRY_NOT_SET = (void *) -1UL;
struct inode *dir = nd->path.dentry->d_inode;
}
if (file->f_mode & FMODE_CREATED)
fsnotify_create(dir, dentry);
- if (unlikely(d_is_negative(dentry))) {
+ if (unlikely(d_is_negative(dentry)))
error = -ENOENT;
- } else {
- path->dentry = dentry;
- path->mnt = nd->path.mnt;
- return 0;
- }
}
}
- dput(dentry);
- return error;
+ if (error) {
+ dput(dentry);
+ dentry = ERR_PTR(error);
+ }
+ return dentry;
}
/*
*
* An error code is returned on failure.
*/
-static int lookup_open(struct nameidata *nd, struct path *path,
- struct file *file,
- const struct open_flags *op,
- bool got_write)
+static struct dentry *lookup_open(struct nameidata *nd, struct file *file,
+ const struct open_flags *op,
+ bool got_write)
{
struct dentry *dir = nd->path.dentry;
struct inode *dir_inode = dir->d_inode;
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
if (unlikely(IS_DEADDIR(dir_inode)))
- return -ENOENT;
+ return ERR_PTR(-ENOENT);
file->f_mode &= ~FMODE_CREATED;
dentry = d_lookup(dir, &nd->last);
if (!dentry) {
dentry = d_alloc_parallel(dir, &nd->last, &wq);
if (IS_ERR(dentry))
- return PTR_ERR(dentry);
+ return dentry;
}
if (d_in_lookup(dentry))
break;
}
if (dentry->d_inode) {
/* Cached positive dentry: will open in f_op->open */
- goto out_no_open;
+ return dentry;
}
/*
}
if (dir_inode->i_op->atomic_open) {
- error = atomic_open(nd, dentry, path, file, op, open_flag,
- mode);
- if (unlikely(error == -ENOENT) && create_error)
- error = create_error;
- return error;
+ dentry = atomic_open(nd, dentry, file, op, open_flag, mode);
+ if (unlikely(create_error) && dentry == ERR_PTR(-ENOENT))
+ dentry = ERR_PTR(create_error);
+ return dentry;
}
no_open:
error = create_error;
goto out_dput;
}
-out_no_open:
- path->dentry = dentry;
- path->mnt = nd->path.mnt;
- return 0;
+ return dentry;
out_dput:
dput(dentry);
- return error;
+ return ERR_PTR(error);
}
/*
int acc_mode = op->acc_mode;
unsigned seq;
struct inode *inode;
- struct path path;
+ struct dentry *dentry;
int error;
nd->flags &= ~LOOKUP_PARENT;
nd->flags |= op->intent;
if (nd->last_type != LAST_NORM) {
+ if (nd->depth)
+ put_link(nd);
error = handle_dots(nd, nd->last_type);
if (unlikely(error))
return error;
if (nd->last.name[nd->last.len])
nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
/* we _can_ be in RCU mode here */
- error = lookup_fast(nd, &path, &inode, &seq);
- if (likely(error > 0))
+ dentry = lookup_fast(nd, &inode, &seq);
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
+ if (likely(dentry))
goto finish_lookup;
- if (error < 0)
- return error;
-
BUG_ON(nd->inode != dir->d_inode);
BUG_ON(nd->flags & LOOKUP_RCU);
} else {
inode_lock(dir->d_inode);
else
inode_lock_shared(dir->d_inode);
- error = lookup_open(nd, &path, file, op, got_write);
+ dentry = lookup_open(nd, file, op, got_write);
if (open_flag & O_CREAT)
inode_unlock(dir->d_inode);
else
inode_unlock_shared(dir->d_inode);
- if (error)
+ if (IS_ERR(dentry)) {
+ error = PTR_ERR(dentry);
goto out;
+ }
if (file->f_mode & FMODE_OPENED) {
if ((file->f_mode & FMODE_CREATED) ||
will_truncate = false;
audit_inode(nd->name, file->f_path.dentry, 0);
+ dput(dentry);
goto opened;
}
open_flag &= ~O_TRUNC;
will_truncate = false;
acc_mode = 0;
- path_to_nameidata(&path, nd);
+ dput(nd->path.dentry);
+ nd->path.dentry = dentry;
goto finish_open_created;
}
got_write = false;
}
- error = follow_managed(&path, nd);
- if (unlikely(error < 0))
+finish_lookup:
+ if (nd->depth)
+ put_link(nd);
+ error = step_into(nd, 0, dentry, inode, seq);
+ if (unlikely(error))
return error;
- /*
- * create/update audit record if it already exists.
- */
- audit_inode(nd->name, path.dentry, 0);
-
if (unlikely((open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT))) {
- path_to_nameidata(&path, nd);
+ audit_inode(nd->name, nd->path.dentry, 0);
return -EEXIST;
}
-
- seq = 0; /* out of RCU mode, so the value doesn't matter */
- inode = d_backing_inode(path.dentry);
-finish_lookup:
- error = step_into(nd, &path, 0, inode, seq);
- if (unlikely(error))
- return error;
finish_open:
/* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */
error = complete_walk(nd);
projects / linux-2.6-microblaze.git / blobdiff