diff options
| -rw-r--r-- | fs/namei.c | 99 |
1 files changed, 61 insertions, 38 deletions
diff --git a/fs/namei.c b/fs/namei.c index 285e62e925f7..fad7117dbb28 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2197,19 +2197,73 @@ static inline int open_to_namei_flags(int flag) } /* + * Lookup, maybe create and open the last component + * + * Must be called with i_mutex held on parent. + * + * Returns open file or NULL on success, error otherwise. NULL means no open + * was performed, only lookup. + */ +static struct file *lookup_open(struct nameidata *nd, struct path *path, + const struct open_flags *op, + int *want_write, bool *created) +{ + struct dentry *dir = nd->path.dentry; + struct dentry *dentry; + int error; + + *created = false; + dentry = lookup_hash(nd); + if (IS_ERR(dentry)) + return ERR_CAST(dentry); + + /* Negative dentry, just create the file */ + if (!dentry->d_inode && (op->open_flag & O_CREAT)) { + umode_t mode = op->mode; + if (!IS_POSIXACL(dir->d_inode)) + mode &= ~current_umask(); + /* + * This write is needed to ensure that a + * rw->ro transition does not occur between + * the time when the file is created and when + * a permanent write count is taken through + * the 'struct file' in nameidata_to_filp(). + */ + error = mnt_want_write(nd->path.mnt); + if (error) + goto out_dput; + *want_write = 1; + *created = true; + error = security_path_mknod(&nd->path, dentry, mode, 0); + if (error) + goto out_dput; + error = vfs_create(dir->d_inode, dentry, mode, nd); + if (error) + goto out_dput; + } + path->dentry = dentry; + path->mnt = nd->path.mnt; + return NULL; + +out_dput: + dput(dentry); + return ERR_PTR(error); +} + +/* * Handle the last step of open() */ static struct file *do_last(struct nameidata *nd, struct path *path, const struct open_flags *op, const char *pathname) { struct dentry *dir = nd->path.dentry; - struct dentry *dentry; int open_flag = op->open_flag; int will_truncate = open_flag & O_TRUNC; int want_write = 0; int acc_mode = op->acc_mode; struct file *filp; struct inode *inode; + bool created; int symlink_ok = 0; struct path save_parent = { .dentry = NULL, .mnt = NULL }; bool retried = false; @@ -2277,53 +2331,24 @@ static struct file *do_last(struct nameidata *nd, struct path *path, retry_lookup: mutex_lock(&dir->d_inode->i_mutex); + filp = lookup_open(nd, path, op, &want_write, &created); + mutex_unlock(&dir->d_inode->i_mutex); - dentry = lookup_hash(nd); - error = PTR_ERR(dentry); - if (IS_ERR(dentry)) { - mutex_unlock(&dir->d_inode->i_mutex); - goto exit; - } - - path->dentry = dentry; - path->mnt = nd->path.mnt; + if (IS_ERR(filp)) + goto out; - /* Negative dentry, just create the file */ - if (!dentry->d_inode && (open_flag & O_CREAT)) { - umode_t mode = op->mode; - if (!IS_POSIXACL(dir->d_inode)) - mode &= ~current_umask(); - /* - * This write is needed to ensure that a - * rw->ro transition does not occur between - * the time when the file is created and when - * a permanent write count is taken through - * the 'struct file' in nameidata_to_filp(). - */ - error = mnt_want_write(nd->path.mnt); - if (error) - goto exit_mutex_unlock; - want_write = 1; + if (created) { /* Don't check for write permission, don't truncate */ open_flag &= ~O_TRUNC; will_truncate = 0; acc_mode = MAY_OPEN; - error = security_path_mknod(&nd->path, dentry, mode, 0); - if (error) - goto exit_mutex_unlock; - error = vfs_create(dir->d_inode, dentry, mode, nd); - if (error) - goto exit_mutex_unlock; - mutex_unlock(&dir->d_inode->i_mutex); - dput(nd->path.dentry); - nd->path.dentry = dentry; + path_to_nameidata(path, nd); goto common; } /* * It already exists. */ - mutex_unlock(&dir->d_inode->i_mutex); audit_inode(pathname, path->dentry); error = -EEXIST; @@ -2432,8 +2457,6 @@ out: terminate_walk(nd); return filp; -exit_mutex_unlock: - mutex_unlock(&dir->d_inode->i_mutex); exit_dput: path_put_conditional(path, nd); exit: |