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| author | Chengguang Xu <cgxu519@zoho.com.cn> | 2019-08-20 18:03:25 +0800 |
|---|---|---|
| committer | Dominique Martinet <dominique.martinet@cea.fr> | 2019-09-03 10:56:32 +0000 |
| commit | c87a37ebd40b889178664c2c09cc187334146292 (patch) | |
| tree | b22de8286db49fc7416431010267f6267c161da4 | |
| parent | 089cf7f6ecb266b6a4164919a2e69bd2f938374a (diff) | |
| download | linux-c87a37ebd40b889178664c2c09cc187334146292.tar.gz linux-c87a37ebd40b889178664c2c09cc187334146292.tar.bz2 linux-c87a37ebd40b889178664c2c09cc187334146292.zip | |
9p: avoid attaching writeback_fid on mmap with type PRIVATE
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>
| -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 4cc966a31cb3..fe7f0bd2048e 100644 --- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -513,6 +513,7 @@ 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 @@ -614,6 +615,8 @@ 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); |