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-rw-r--r--fs/namei.c177
1 files changed, 127 insertions, 50 deletions
diff --git a/fs/namei.c b/fs/namei.c
index c651f02c9fe..7d694194024 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -449,7 +449,7 @@ static int unlazy_walk(struct nameidata *nd, struct dentry *dentry)
mntget(nd->path.mnt);
rcu_read_unlock();
- br_read_unlock(vfsmount_lock);
+ br_read_unlock(&vfsmount_lock);
nd->flags &= ~LOOKUP_RCU;
return 0;
@@ -507,14 +507,14 @@ static int complete_walk(struct nameidata *nd)
if (unlikely(!__d_rcu_to_refcount(dentry, nd->seq))) {
spin_unlock(&dentry->d_lock);
rcu_read_unlock();
- br_read_unlock(vfsmount_lock);
+ br_read_unlock(&vfsmount_lock);
return -ECHILD;
}
BUG_ON(nd->inode != dentry->d_inode);
spin_unlock(&dentry->d_lock);
mntget(nd->path.mnt);
rcu_read_unlock();
- br_read_unlock(vfsmount_lock);
+ br_read_unlock(&vfsmount_lock);
}
if (likely(!(nd->flags & LOOKUP_JUMPED)))
@@ -681,15 +681,15 @@ int follow_up(struct path *path)
struct mount *parent;
struct dentry *mountpoint;
- br_read_lock(vfsmount_lock);
+ br_read_lock(&vfsmount_lock);
parent = mnt->mnt_parent;
if (&parent->mnt == path->mnt) {
- br_read_unlock(vfsmount_lock);
+ br_read_unlock(&vfsmount_lock);
return 0;
}
mntget(&parent->mnt);
mountpoint = dget(mnt->mnt_mountpoint);
- br_read_unlock(vfsmount_lock);
+ br_read_unlock(&vfsmount_lock);
dput(path->dentry);
path->dentry = mountpoint;
mntput(path->mnt);
@@ -947,7 +947,7 @@ failed:
if (!(nd->flags & LOOKUP_ROOT))
nd->root.mnt = NULL;
rcu_read_unlock();
- br_read_unlock(vfsmount_lock);
+ br_read_unlock(&vfsmount_lock);
return -ECHILD;
}
@@ -1125,8 +1125,8 @@ static struct dentry *__lookup_hash(struct qstr *name,
* small and for now I'd prefer to have fast path as straight as possible.
* It _is_ time-critical.
*/
-static int do_lookup(struct nameidata *nd, struct qstr *name,
- struct path *path, struct inode **inode)
+static int lookup_fast(struct nameidata *nd, struct qstr *name,
+ struct path *path, struct inode **inode)
{
struct vfsmount *mnt = nd->path.mnt;
struct dentry *dentry, *parent = nd->path.dentry;
@@ -1208,7 +1208,7 @@ unlazy:
goto need_lookup;
}
}
-done:
+
path->mnt = mnt;
path->dentry = dentry;
err = follow_managed(path, nd->flags);
@@ -1222,6 +1222,17 @@ done:
return 0;
need_lookup:
+ return 1;
+}
+
+/* Fast lookup failed, do it the slow way */
+static int lookup_slow(struct nameidata *nd, struct qstr *name,
+ struct path *path)
+{
+ struct dentry *dentry, *parent;
+ int err;
+
+ parent = nd->path.dentry;
BUG_ON(nd->inode != parent->d_inode);
mutex_lock(&parent->d_inode->i_mutex);
@@ -1229,7 +1240,16 @@ need_lookup:
mutex_unlock(&parent->d_inode->i_mutex);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
- goto done;
+ path->mnt = nd->path.mnt;
+ path->dentry = dentry;
+ err = follow_managed(path, nd->flags);
+ if (unlikely(err < 0)) {
+ path_put_conditional(path, nd);
+ return err;
+ }
+ if (err)
+ nd->flags |= LOOKUP_JUMPED;
+ return 0;
}
static inline int may_lookup(struct nameidata *nd)
@@ -1265,7 +1285,7 @@ static void terminate_walk(struct nameidata *nd)
if (!(nd->flags & LOOKUP_ROOT))
nd->root.mnt = NULL;
rcu_read_unlock();
- br_read_unlock(vfsmount_lock);
+ br_read_unlock(&vfsmount_lock);
}
}
@@ -1301,21 +1321,26 @@ static inline int walk_component(struct nameidata *nd, struct path *path,
*/
if (unlikely(type != LAST_NORM))
return handle_dots(nd, type);
- err = do_lookup(nd, name, path, &inode);
+ err = lookup_fast(nd, name, path, &inode);
if (unlikely(err)) {
- terminate_walk(nd);
- return err;
- }
- if (!inode) {
- path_to_nameidata(path, nd);
- terminate_walk(nd);
- return -ENOENT;
+ if (err < 0)
+ goto out_err;
+
+ err = lookup_slow(nd, name, path);
+ if (err < 0)
+ goto out_err;
+
+ inode = path->dentry->d_inode;
}
+ err = -ENOENT;
+ if (!inode)
+ goto out_path_put;
+
if (should_follow_link(inode, follow)) {
if (nd->flags & LOOKUP_RCU) {
if (unlikely(unlazy_walk(nd, path->dentry))) {
- terminate_walk(nd);
- return -ECHILD;
+ err = -ECHILD;
+ goto out_err;
}
}
BUG_ON(inode != path->dentry->d_inode);
@@ -1324,6 +1349,12 @@ static inline int walk_component(struct nameidata *nd, struct path *path,
path_to_nameidata(path, nd);
nd->inode = inode;
return 0;
+
+out_path_put:
+ path_to_nameidata(path, nd);
+out_err:
+ terminate_walk(nd);
+ return err;
}
/*
@@ -1620,7 +1651,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
nd->path = nd->root;
nd->inode = inode;
if (flags & LOOKUP_RCU) {
- br_read_lock(vfsmount_lock);
+ br_read_lock(&vfsmount_lock);
rcu_read_lock();
nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
} else {
@@ -1633,7 +1664,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
if (*name=='/') {
if (flags & LOOKUP_RCU) {
- br_read_lock(vfsmount_lock);
+ br_read_lock(&vfsmount_lock);
rcu_read_lock();
set_root_rcu(nd);
} else {
@@ -1646,7 +1677,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
struct fs_struct *fs = current->fs;
unsigned seq;
- br_read_lock(vfsmount_lock);
+ br_read_lock(&vfsmount_lock);
rcu_read_lock();
do {
@@ -1682,7 +1713,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
if (fput_needed)
*fp = file;
nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
- br_read_lock(vfsmount_lock);
+ br_read_lock(&vfsmount_lock);
rcu_read_lock();
} else {
path_get(&file->f_path);
@@ -2169,6 +2200,10 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
int want_write = 0;
int acc_mode = op->acc_mode;
struct file *filp;
+ struct inode *inode;
+ int symlink_ok = 0;
+ struct path save_parent = { .dentry = NULL, .mnt = NULL };
+ bool retried = false;
int error;
nd->flags &= ~LOOKUP_PARENT;
@@ -2200,30 +2235,23 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
}
if (!(open_flag & O_CREAT)) {
- int symlink_ok = 0;
if (nd->last.name[nd->last.len])
nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
if (open_flag & O_PATH && !(nd->flags & LOOKUP_FOLLOW))
symlink_ok = 1;
/* we _can_ be in RCU mode here */
- error = walk_component(nd, path, &nd->last, LAST_NORM,
- !symlink_ok);
- if (error < 0)
- return ERR_PTR(error);
- if (error) /* symlink */
- return NULL;
- /* sayonara */
- error = complete_walk(nd);
- if (error)
- return ERR_PTR(error);
+ error = lookup_fast(nd, &nd->last, path, &inode);
+ if (unlikely(error)) {
+ if (error < 0)
+ goto exit;
- error = -ENOTDIR;
- if (nd->flags & LOOKUP_DIRECTORY) {
- if (!nd->inode->i_op->lookup)
+ error = lookup_slow(nd, &nd->last, path);
+ if (error < 0)
goto exit;
+
+ inode = path->dentry->d_inode;
}
- audit_inode(pathname, nd->path.dentry);
- goto ok;
+ goto finish_lookup;
}
/* create side of things */
@@ -2241,6 +2269,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
if (nd->last.name[nd->last.len])
goto exit;
+retry_lookup:
mutex_lock(&dir->d_inode->i_mutex);
dentry = lookup_hash(nd);
@@ -2302,22 +2331,49 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
if (error)
nd->flags |= LOOKUP_JUMPED;
+ BUG_ON(nd->flags & LOOKUP_RCU);
+ inode = path->dentry->d_inode;
+finish_lookup:
+ /* we _can_ be in RCU mode here */
error = -ENOENT;
- if (!path->dentry->d_inode)
- goto exit_dput;
+ if (!inode) {
+ path_to_nameidata(path, nd);
+ goto exit;
+ }
- if (path->dentry->d_inode->i_op->follow_link)
+ if (should_follow_link(inode, !symlink_ok)) {
+ if (nd->flags & LOOKUP_RCU) {
+ if (unlikely(unlazy_walk(nd, path->dentry))) {
+ error = -ECHILD;
+ goto exit;
+ }
+ }
+ BUG_ON(inode != path->dentry->d_inode);
return NULL;
+ }
- path_to_nameidata(path, nd);
- nd->inode = path->dentry->d_inode;
+ if ((nd->flags & LOOKUP_RCU) || nd->path.mnt != path->mnt) {
+ path_to_nameidata(path, nd);
+ } else {
+ save_parent.dentry = nd->path.dentry;
+ save_parent.mnt = mntget(path->mnt);
+ nd->path.dentry = path->dentry;
+
+ }
+ nd->inode = inode;
/* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */
error = complete_walk(nd);
- if (error)
+ if (error) {
+ path_put(&save_parent);
return ERR_PTR(error);
+ }
error = -EISDIR;
- if (S_ISDIR(nd->inode->i_mode))
+ if ((open_flag & O_CREAT) && S_ISDIR(nd->inode->i_mode))
+ goto exit;
+ error = -ENOTDIR;
+ if ((nd->flags & LOOKUP_DIRECTORY) && !nd->inode->i_op->lookup)
goto exit;
+ audit_inode(pathname, nd->path.dentry);
ok:
if (!S_ISREG(nd->inode->i_mode))
will_truncate = 0;
@@ -2333,6 +2389,20 @@ common:
if (error)
goto exit;
filp = nameidata_to_filp(nd);
+ if (filp == ERR_PTR(-EOPENSTALE) && save_parent.dentry && !retried) {
+ BUG_ON(save_parent.dentry != dir);
+ path_put(&nd->path);
+ nd->path = save_parent;
+ nd->inode = dir->d_inode;
+ save_parent.mnt = NULL;
+ save_parent.dentry = NULL;
+ if (want_write) {
+ mnt_drop_write(nd->path.mnt);
+ want_write = 0;
+ }
+ retried = true;
+ goto retry_lookup;
+ }
if (!IS_ERR(filp)) {
error = ima_file_check(filp, op->acc_mode);
if (error) {
@@ -2352,7 +2422,8 @@ common:
out:
if (want_write)
mnt_drop_write(nd->path.mnt);
- path_put(&nd->path);
+ path_put(&save_parent);
+ terminate_walk(nd);
return filp;
exit_mutex_unlock:
@@ -2415,6 +2486,12 @@ out:
if (base)
fput(base);
release_open_intent(nd);
+ if (filp == ERR_PTR(-EOPENSTALE)) {
+ if (flags & LOOKUP_RCU)
+ filp = ERR_PTR(-ECHILD);
+ else
+ filp = ERR_PTR(-ESTALE);
+ }
return filp;
out_filp:
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-22 11:28:46 +0000