if (need_mntput && path->mnt == mnt)
mntput(path->mnt);
- if (ret == -EISDIR)
- ret = 0;
+ if (ret == -EISDIR || !ret)
+ ret = 1;
if (need_mntput)
nd->flags |= LOOKUP_JUMPED;
if (unlikely(ret < 0))
* This looks up the name in dcache, possibly revalidates the old dentry and
* allocates a new one if not found or not valid. In the need_lookup argument
* returns whether i_op->lookup is necessary.
- *
- * dir->d_inode->i_mutex must be held
*/
-static struct dentry *lookup_dcache(struct qstr *name, struct dentry *dir,
- unsigned int flags, bool *need_lookup)
+static struct dentry *lookup_dcache(const struct qstr *name,
+ struct dentry *dir,
+ unsigned int flags)
{
struct dentry *dentry;
int error;
- *need_lookup = false;
dentry = d_lookup(dir, name);
if (dentry) {
if (dentry->d_flags & DCACHE_OP_REVALIDATE) {
error = d_revalidate(dentry, flags);
if (unlikely(error <= 0)) {
- if (error < 0) {
- dput(dentry);
- return ERR_PTR(error);
- } else {
+ if (!error)
d_invalidate(dentry);
- dput(dentry);
- dentry = NULL;
- }
+ dput(dentry);
+ return ERR_PTR(error);
}
}
}
-
- if (!dentry) {
- dentry = d_alloc(dir, name);
- if (unlikely(!dentry))
- return ERR_PTR(-ENOMEM);
-
- *need_lookup = true;
- }
return dentry;
}
return dentry;
}
-static struct dentry *__lookup_hash(struct qstr *name,
+static struct dentry *__lookup_hash(const struct qstr *name,
struct dentry *base, unsigned int flags)
{
- bool need_lookup;
- struct dentry *dentry;
+ struct dentry *dentry = lookup_dcache(name, base, flags);
- dentry = lookup_dcache(name, base, flags, &need_lookup);
- if (!need_lookup)
+ if (dentry)
return dentry;
+ dentry = d_alloc(base, name);
+ if (unlikely(!dentry))
+ return ERR_PTR(-ENOMEM);
+
return lookup_real(base->d_inode, dentry, flags);
}
-/*
- * It's more convoluted than I'd like it to be, but... it's still fairly
- * small and for now I'd prefer to have fast path as straight as possible.
- * It _is_ time-critical.
- */
static int lookup_fast(struct nameidata *nd,
struct path *path, struct inode **inode,
unsigned *seqp)
{
struct vfsmount *mnt = nd->path.mnt;
struct dentry *dentry, *parent = nd->path.dentry;
- int need_reval = 1;
int status = 1;
int err;
/*
* Rename seqlock is not required here because in the off chance
- * of a false negative due to a concurrent rename, we're going to
- * do the non-racy lookup, below.
+ * of a false negative due to a concurrent rename, the caller is
+ * going to fall back to non-racy lookup.
*/
if (nd->flags & LOOKUP_RCU) {
unsigned seq;
bool negative;
dentry = __d_lookup_rcu(parent, &nd->last, &seq);
- if (!dentry)
- goto unlazy;
+ if (unlikely(!dentry)) {
+ if (unlazy_walk(nd, NULL, 0))
+ return -ECHILD;
+ return 0;
+ }
/*
* This sequence count validates that the inode matches
*/
*inode = d_backing_inode(dentry);
negative = d_is_negative(dentry);
- if (read_seqcount_retry(&dentry->d_seq, seq))
+ if (unlikely(read_seqcount_retry(&dentry->d_seq, seq)))
return -ECHILD;
/*
* The memory barrier in read_seqcount_begin of child is
* enough, we can use __read_seqcount_retry here.
*/
- if (__read_seqcount_retry(&parent->d_seq, nd->seq))
+ if (unlikely(__read_seqcount_retry(&parent->d_seq, nd->seq)))
return -ECHILD;
*seqp = seq;
- if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) {
+ if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE))
status = d_revalidate(dentry, nd->flags);
- if (unlikely(status <= 0)) {
- if (status != -ECHILD)
- need_reval = 0;
- goto unlazy;
- }
+ if (unlikely(status <= 0)) {
+ if (unlazy_walk(nd, dentry, seq))
+ return -ECHILD;
+ if (status == -ECHILD)
+ status = d_revalidate(dentry, nd->flags);
+ } else {
+ /*
+ * 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 (unlazy_walk(nd, dentry, seq))
+ return -ECHILD;
}
- /*
- * Note: do negative dentry check after revalidation in
- * case that drops it.
- */
- if (negative)
- return -ENOENT;
- path->mnt = mnt;
- path->dentry = dentry;
- if (likely(__follow_mount_rcu(nd, path, inode, seqp)))
- return 0;
-unlazy:
- if (unlazy_walk(nd, dentry, seq))
- return -ECHILD;
} else {
dentry = __d_lookup(parent, &nd->last);
+ if (unlikely(!dentry))
+ return 0;
+ if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE))
+ status = d_revalidate(dentry, nd->flags);
}
-
- if (unlikely(!dentry))
- goto need_lookup;
-
- if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE) && need_reval)
- status = d_revalidate(dentry, nd->flags);
if (unlikely(status <= 0)) {
- if (status < 0) {
- dput(dentry);
- return status;
- }
- d_invalidate(dentry);
+ if (!status)
+ d_invalidate(dentry);
dput(dentry);
- goto need_lookup;
+ return status;
}
-
if (unlikely(d_is_negative(dentry))) {
dput(dentry);
return -ENOENT;
}
+
path->mnt = mnt;
path->dentry = dentry;
err = follow_managed(path, nd);
- if (likely(!err))
+ if (likely(err > 0))
*inode = d_backing_inode(path->dentry);
return err;
-
-need_lookup:
- return 1;
}
/* Fast lookup failed, do it the slow way */
-static int lookup_slow(struct nameidata *nd, struct path *path)
+static struct dentry *lookup_slow(const struct qstr *name,
+ struct dentry *dir,
+ unsigned int flags)
{
- struct dentry *dentry, *parent;
-
- parent = nd->path.dentry;
- BUG_ON(nd->inode != parent->d_inode);
-
- inode_lock(parent->d_inode);
- dentry = __lookup_hash(&nd->last, parent, nd->flags);
- inode_unlock(parent->d_inode);
- if (IS_ERR(dentry))
- return PTR_ERR(dentry);
- path->mnt = nd->path.mnt;
- path->dentry = dentry;
- return follow_managed(path, nd);
+ struct dentry *dentry;
+ inode_lock(dir->d_inode);
+ dentry = d_lookup(dir, name);
+ if (unlikely(dentry)) {
+ if ((dentry->d_flags & DCACHE_OP_REVALIDATE) &&
+ !(flags & LOOKUP_NO_REVAL)) {
+ int error = d_revalidate(dentry, flags);
+ if (unlikely(error <= 0)) {
+ if (!error)
+ d_invalidate(dentry);
+ dput(dentry);
+ dentry = ERR_PTR(error);
+ }
+ }
+ if (dentry) {
+ inode_unlock(dir->d_inode);
+ return dentry;
+ }
+ }
+ dentry = d_alloc(dir, name);
+ if (unlikely(!dentry)) {
+ inode_unlock(dir->d_inode);
+ return ERR_PTR(-ENOMEM);
+ }
+ dentry = lookup_real(dir->d_inode, dentry, flags);
+ inode_unlock(dir->d_inode);
+ return dentry;
}
static inline int may_lookup(struct nameidata *nd)
return err;
}
err = lookup_fast(nd, &path, &inode, &seq);
- if (unlikely(err)) {
+ if (unlikely(err <= 0)) {
if (err < 0)
return err;
-
- err = lookup_slow(nd, &path);
- if (err < 0)
+ path.dentry = lookup_slow(&nd->last, nd->path.dentry,
+ nd->flags);
+ if (IS_ERR(path.dentry))
+ return PTR_ERR(path.dentry);
+ if (unlikely(d_is_negative(path.dentry))) {
+ dput(path.dentry);
+ return -ENOENT;
+ }
+ 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 */
- err = -ENOENT;
- if (d_is_negative(path.dentry))
- goto out_path_put;
inode = d_backing_inode(path.dentry);
}
nd->inode = inode;
nd->seq = seq;
return 0;
-
-out_path_put:
- path_to_nameidata(&path, nd);
- return err;
}
/*
if (err)
return ERR_PTR(err);
- /*
- * __d_lookup() is used to try to get a quick answer and avoid the
- * mutex. A false-negative does no harm.
- */
- ret = __d_lookup(base, &this);
- if (ret && unlikely(ret->d_flags & DCACHE_OP_REVALIDATE)) {
- dput(ret);
- ret = NULL;
- }
- if (ret)
- return ret;
-
- inode_lock(base->d_inode);
- ret = __lookup_hash(&this, base, 0);
- inode_unlock(base->d_inode);
+ ret = lookup_dcache(&this, base, 0);
+ if (!ret)
+ ret = lookup_slow(&this, base, 0);
return ret;
}
EXPORT_SYMBOL(lookup_one_len_unlocked);
if (error)
return error;
dentry = dget(nd->path.dentry);
- goto done;
- }
-
- inode_lock(dir->d_inode);
- dentry = d_lookup(dir, &nd->last);
- if (!dentry) {
- /*
- * No cached dentry. Mounted dentries are pinned in the cache,
- * so that means that this dentry is probably a symlink or the
- * path doesn't actually point to a mounted dentry.
- */
- dentry = d_alloc(dir, &nd->last);
+ } else {
+ dentry = d_lookup(dir, &nd->last);
if (!dentry) {
- inode_unlock(dir->d_inode);
- return -ENOMEM;
- }
- dentry = lookup_real(dir->d_inode, dentry, nd->flags);
- if (IS_ERR(dentry)) {
- inode_unlock(dir->d_inode);
- return PTR_ERR(dentry);
+ /*
+ * No cached dentry. Mounted dentries are pinned in the
+ * cache, so that means that this dentry is probably
+ * a symlink or the path doesn't actually point
+ * to a mounted dentry.
+ */
+ dentry = lookup_slow(&nd->last, dir,
+ nd->flags | LOOKUP_NO_REVAL);
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
}
}
- inode_unlock(dir->d_inode);
-
-done:
if (d_is_negative(dentry)) {
dput(dentry);
return -ENOENT;
struct inode *dir_inode = dir->d_inode;
struct dentry *dentry;
int error;
- bool need_lookup;
+ bool need_lookup = false;
*opened &= ~FILE_CREATED;
- dentry = lookup_dcache(&nd->last, dir, nd->flags, &need_lookup);
+ dentry = lookup_dcache(&nd->last, dir, nd->flags);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
- /* Cached positive dentry: will open in f_op->open */
- if (!need_lookup && dentry->d_inode)
+ if (!dentry) {
+ dentry = d_alloc(dir, &nd->last);
+ if (unlikely(!dentry))
+ return -ENOMEM;
+ need_lookup = true;
+ } else if (dentry->d_inode) {
+ /* Cached positive dentry: will open in f_op->open */
goto out_no_open;
+ }
if ((nd->flags & LOOKUP_OPEN) && dir_inode->i_op->atomic_open) {
return atomic_open(nd, dentry, path, file, op, got_write,
nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
/* we _can_ be in RCU mode here */
error = lookup_fast(nd, &path, &inode, &seq);
- if (likely(!error))
+ if (likely(error > 0))
goto finish_lookup;
if (error < 0)
return error;
BUG_ON(nd->inode != dir->d_inode);
+ BUG_ON(nd->flags & LOOKUP_RCU);
} else {
/* create side of things */
/*
goto finish_open_created;
}
- /*
- * create/update audit record if it already exists.
- */
- if (d_is_positive(path.dentry))
- audit_inode(nd->name, path.dentry, 0);
-
/*
* If atomic_open() acquired write access it is dropped now due to
* possible mount and symlink following (this might be optimized away if
got_write = false;
}
+ if (unlikely(d_is_negative(path.dentry))) {
+ path_to_nameidata(&path, nd);
+ return -ENOENT;
+ }
+
+ /*
+ * 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);
return -EEXIST;
if (unlikely(error < 0))
return error;
- BUG_ON(nd->flags & LOOKUP_RCU);
seq = 0; /* out of RCU mode, so the value doesn't matter */
- if (unlikely(d_is_negative(path.dentry))) {
- path_to_nameidata(&path, nd);
- return -ENOENT;
- }
inode = d_backing_inode(path.dentry);
finish_lookup:
if (nd->depth)
return sys_mkdirat(AT_FDCWD, pathname, mode);
}
-/*
- * The dentry_unhash() helper will try to drop the dentry early: we
- * should have a usage count of 1 if we're the only user of this
- * dentry, and if that is true (possibly after pruning the dcache),
- * then we drop the dentry now.
- *
- * A low-level filesystem can, if it choses, legally
- * do a
- *
- * if (!d_unhashed(dentry))
- * return -EBUSY;
- *
- * if it cannot handle the case of removing a directory
- * that is still in use by something else..
- */
-void dentry_unhash(struct dentry *dentry)
-{
- shrink_dcache_parent(dentry);
- spin_lock(&dentry->d_lock);
- if (dentry->d_lockref.count == 1)
- __d_drop(dentry);
- spin_unlock(&dentry->d_lock);
-}
-EXPORT_SYMBOL(dentry_unhash);
-
int vfs_rmdir(struct inode *dir, struct dentry *dentry)
{
int error = may_delete(dir, dentry, 1);
projects / cascardo / linux.git / blobdiff