diff options
| -rw-r--r-- | ipc/mqueue.c | 61 |
1 files changed, 28 insertions, 33 deletions
diff --git a/ipc/mqueue.c b/ipc/mqueue.c index f8e54f5b908..9a08acc9e64 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -726,7 +726,6 @@ static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir, struct mq_attr *attr) { const struct cred *cred = current_cred(); - struct file *result; int ret; if (attr) { @@ -748,21 +747,11 @@ static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir, } mode &= ~current_umask(); - ret = mnt_want_write(path->mnt); - if (ret) - return ERR_PTR(ret); ret = vfs_create(dir, path->dentry, mode, true); path->dentry->d_fsdata = NULL; - if (!ret) - result = dentry_open(path, oflag, cred); - else - result = ERR_PTR(ret); - /* - * dentry_open() took a persistent mnt_want_write(), - * so we can now drop this one. - */ - mnt_drop_write(path->mnt); - return result; + if (ret) + return ERR_PTR(ret); + return dentry_open(path, oflag, cred); } /* Opens existing queue */ @@ -788,7 +777,9 @@ SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode, struct mq_attr attr; int fd, error; struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; - struct dentry *root = ipc_ns->mq_mnt->mnt_root; + struct vfsmount *mnt = ipc_ns->mq_mnt; + struct dentry *root = mnt->mnt_root; + int ro; if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr))) return -EFAULT; @@ -802,6 +793,7 @@ SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode, if (fd < 0) goto out_putname; + ro = mnt_want_write(mnt); /* we'll drop it in any case */ error = 0; mutex_lock(&root->d_inode->i_mutex); path.dentry = lookup_one_len(name, root, strlen(name)); @@ -809,7 +801,7 @@ SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode, error = PTR_ERR(path.dentry); goto out_putfd; } - path.mnt = mntget(ipc_ns->mq_mnt); + path.mnt = mntget(mnt); if (oflag & O_CREAT) { if (path.dentry->d_inode) { /* entry already exists */ @@ -820,6 +812,10 @@ SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode, } filp = do_open(&path, oflag); } else { + if (ro) { + error = ro; + goto out; + } filp = do_create(ipc_ns, root->d_inode, &path, oflag, mode, u_attr ? &attr : NULL); @@ -845,6 +841,7 @@ out_putfd: fd = error; } mutex_unlock(&root->d_inode->i_mutex); + mnt_drop_write(mnt); out_putname: putname(name); return fd; @@ -857,40 +854,38 @@ SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name) struct dentry *dentry; struct inode *inode = NULL; struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; + struct vfsmount *mnt = ipc_ns->mq_mnt; name = getname(u_name); if (IS_ERR(name)) return PTR_ERR(name); - mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex, - I_MUTEX_PARENT); - dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name)); + err = mnt_want_write(mnt); + if (err) + goto out_name; + mutex_lock_nested(&mnt->mnt_root->d_inode->i_mutex, I_MUTEX_PARENT); + dentry = lookup_one_len(name, mnt->mnt_root, strlen(name)); if (IS_ERR(dentry)) { err = PTR_ERR(dentry); goto out_unlock; } - if (!dentry->d_inode) { - err = -ENOENT; - goto out_err; - } - inode = dentry->d_inode; - if (inode) + if (!inode) { + err = -ENOENT; + } else { ihold(inode); - err = mnt_want_write(ipc_ns->mq_mnt); - if (err) - goto out_err; - err = vfs_unlink(dentry->d_parent->d_inode, dentry); - mnt_drop_write(ipc_ns->mq_mnt); -out_err: + err = vfs_unlink(dentry->d_parent->d_inode, dentry); + } dput(dentry); out_unlock: - mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex); - putname(name); + mutex_unlock(&mnt->mnt_root->d_inode->i_mutex); if (inode) iput(inode); + mnt_drop_write(mnt); +out_name: + putname(name); return err; } |