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| author | Chengguang Xu <cgxu519@zoho.com.cn> | 2019-08-20 18:03:25 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-17 13:40:54 -0700 |
| commit | 06453e2abdd2ec2ff40fc0324adead84ff4899b7 (patch) | |
| tree | b6ddd0f1a0ba1b2ba38670a4df48fcf5729990c7 | |
| parent | 5deaece94aa9f3be912ec2c61483ba876fcef12e (diff) | |
9p: avoid attaching writeback_fid on mmap with type PRIVATE
[ Upstream commit c87a37ebd40b889178664c2c09cc187334146292 ]
Currently on mmap cache policy, we always attach writeback_fid
whether mmap type is SHARED or PRIVATE. However, in the use case
of kata-container which combines 9p(Guest OS) with overlayfs(Host OS),
this behavior will trigger overlayfs' copy-up when excute command
inside container.
Link: http://lkml.kernel.org/r/20190820100325.10313-1-cgxu519@zoho.com.cn
Signed-off-by: Chengguang Xu <cgxu519@zoho.com.cn>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | fs/9p/vfs_file.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c index 373cc50544e9..9dbf37147126 100644 --- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -528,6 +528,7 @@ v9fs_mmap_file_mmap(struct file *filp, struct vm_area_struct *vma) v9inode = V9FS_I(inode); mutex_lock(&v9inode->v_mutex); if (!v9inode->writeback_fid && + (vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE)) { /* * clone a fid and add it to writeback_fid @@ -629,6 +630,8 @@ static void v9fs_mmap_vm_close(struct vm_area_struct *vma) (vma->vm_end - vma->vm_start - 1), }; + if (!(vma->vm_flags & VM_SHARED)) + return; p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma); |