Dirty pages weren't being written back when an mmap'ed eCryptfs file was
closed before the mapping was unmapped. Since f_ops->flush() is not
called by the munmap() path, the lower file was simply being released.
This patch flushes the eCryptfs file in the vm_ops->close() path.

https://launchpad.net/bugs/870326

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
---

Upstream: 32001d6fe9ac6b0423e674a3093aa56740849f3b
Discussion: https://lkml.org/lkml/2011/11/23/495

This is the upstream commit applied to ubuntu-oneiric/master-next. Linus wasn't
entirely happy with the patch, but he did take it in. I agree with his
criticism of the patch but this is a minimal fix to a critical bug and
implementing his suggestions will take a little more time.

I've been testing the patch (and using it daily) over the last week and have
had 0 issues.

fs/ecryptfs/file.c | 23 ++++++++++++++++++++++-
1 files changed, 22 insertions(+), 1 deletions(-)

diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 4ec9eb0..0c1a652 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -139,6 +139,27 @@ out:
return rc;
}

+static void ecryptfs_vma_close(struct vm_area_struct *vma)
+{
+ filemap_write_and_wait(vma->vm_file->f_mapping);
+}
+
+static const struct vm_operations_struct ecryptfs_file_vm_ops = {
+ .close = ecryptfs_vma_close,
+ .fault = filemap_fault,
+};
+
+static int ecryptfs_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ int rc;
+
+ rc = generic_file_mmap(file, vma);
+ if (!rc)
+ vma->vm_ops = &ecryptfs_file_vm_ops;
+
+ return rc;
+}
+
struct kmem_cache *ecryptfs_file_info_cache;

/**
@@ -348,7 +369,7 @@ const struct file_operations ecryptfs_main_fops = {
#ifdef CONFIG_COMPAT
.compat_ioctl = ecryptfs_compat_ioctl,
#endif
- .mmap = generic_file_mmap,
+ .mmap = ecryptfs_file_mmap,
.open = ecryptfs_open,
.flush = ecryptfs_flush,
.release = ecryptfs_release,
--
1.7.5.4


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