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From:   Chengguang Xu <cgxu519@mykernel.net>
To:     ericvh@gmail.com, lucho@ionkov.net, asmadeus@codewreck.org
Cc:     v9fs-developer@lists.sourceforge.net, linux-kernel@vger.kernel.org,
        Chengguang Xu <cgxu519@mykernel.net>
Message-ID: <20201207143329.32730-1-cgxu519@mykernel.net>
Subject: [V9fs-developer][PATCH v2] 9p: create writeback fid on shared writable mmap
Date:   Mon,  7 Dec 2020 22:33:29 +0800
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If vma is shared and the file was opened for writing,
we should also create writeback fid because vma may be
mprotected writable even if now readonly.

Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
---
 fs/9p/vfs_file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index b177fd3b1eb3..e4256dbcb754 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -517,7 +517,7 @@ v9fs_mmap_file_mmap(struct file *filp, struct vm_area_s=
truct *vma)
 =09mutex_lock(&v9inode->v_mutex);
 =09if (!v9inode->writeback_fid &&
 =09    (vma->vm_flags & VM_SHARED) &&
-=09    (vma->vm_flags & VM_WRITE)) {
+=09    (vma->vm_flags & VM_MAYWRITE)) {
 =09=09/*
 =09=09 * clone a fid and add it to writeback_fid
 =09=09 * we do it during mmap instead of
--=20
2.26.2