LU-11944 llite: Lock inode on tiny write if setuid/setgid set

During a write, the setuid/setgid bits must be reset if they are
enabled and the user does not have the correct permissions. Setting
any file attributes, including setuid and setgid, requires the inode
to be locked. Writes became lockless with the introduction of
LU-1669. Locking the inode in the setuid/setgid case was added to
vvp_io_write_start() as a special case. The inode locking was not
included when support for tiny writes was added with LU-9409. This
mod adds the necessary inode lock/unlock calls to ll_do_tiny_write().

If the inode is not locked when setuid/setgid are reset, the kernel
will issue a one time warning and Lustre may hang trying to get the
inode lock in ll_setattr_raw().

Lustre-change: https://review.whamcloud.com/34218
Lustre-commit: f39a552922ca2db0c6974374fa3a917a34a4a747

Signed-off-by: Ann Koehler <amk@cray.com>
Change-Id: I5e8a98789828de52dbff4226958741320aba92e6
Reviewed-by: Patrick Farrell <pfarrell@whamcloud.com>
Reviewed-by: Ben Evans <bevans@cray.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Signed-off-by: Minh Diep <mdiep@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/34461
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lustre/llite/file.c b/lustre/llite/file.c
index 5e649de..5d6af43 100644 (file)
--- a/lustre/llite/file.c
+++ b/lustre/llite/file.c
@@ -1619,8 +1619,9 @@ out:
 static ssize_t ll_do_tiny_write(struct kiocb *iocb, struct iov_iter *iter)
 {
        ssize_t count = iov_iter_count(iter);
-       struct file *file = iocb->ki_filp;
-       struct inode *inode = file_inode(file);
+       struct  file *file = iocb->ki_filp;
+       struct  inode *inode = file_inode(file);
+       bool    lock_inode = !IS_NOSEC(inode);
        ssize_t result = 0;
 
        ENTRY;
@@ -1632,8 +1633,13 @@ static ssize_t ll_do_tiny_write(struct kiocb *iocb, struct iov_iter *iter)
            (iocb->ki_pos & (PAGE_SIZE-1)) + count > PAGE_SIZE)
                RETURN(0);
 
+       if (unlikely(lock_inode))
+               inode_lock(inode);
        result = __generic_file_write_iter(iocb, iter);
 
+       if (unlikely(lock_inode))
+               inode_unlock(inode);
+
        /* If the page is not already dirty, ll_tiny_write_begin returns
         * -ENODATA.  We continue on to normal write.
         */

diff --git a/lustre/llite/vvp_io.c b/lustre/llite/vvp_io.c
index 22bf50e..212ac9d 100644 (file)
--- a/lustre/llite/vvp_io.c
+++ b/lustre/llite/vvp_io.c
@@ -1092,13 +1092,13 @@ static int vvp_io_write_start(const struct lu_env *env,
                 * consistency, proper locking to protect against writes,
                 * trucates, etc. is handled in the higher layers of lustre.
                 */
-               bool lock_node = !IS_NOSEC(inode);
+               lock_inode = !IS_NOSEC(inode);
 
-               if (lock_node)
+               if (unlikely(lock_inode))
                        inode_lock(inode);
                result = __generic_file_write_iter(vio->vui_iocb,
                                                   vio->vui_iter);
-               if (lock_node)
+               if (unlikely(lock_inode))
                        inode_unlock(inode);
 
                if (result > 0 || result == -EIOCBQUEUED)