Patchwork [1/2] eCryptfs: Write out all dirty pages just before releasing the lower file

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Submitter Colin King
Date Sept. 15, 2012, 7:09 p.m.
Message ID <1347736154-5577-2-git-send-email-colin.king@canonical.com>
Download mbox | patch
Permalink /patch/184094/
State New
Headers show

Comments

Colin King - Sept. 15, 2012, 7:09 p.m.
From: Tyler Hicks <tyhicks@canonical.com>

Fixes a regression caused by:

821f749 eCryptfs: Revert to a writethrough cache model

That patch reverted some code (specifically, 32001d6f) that was
necessary to properly handle open() -> mmap() -> close() -> dirty pages
-> munmap(), because the lower file could be closed before the dirty
pages are written out.

Rather than reapplying 32001d6f, this approach is a better way of
ensuring that the lower file is still open in order to handle writing
out the dirty pages. It is called from ecryptfs_release(), while we have
a lock on the lower file pointer, just before the lower file gets the
final fput() and we overwrite the pointer.

BugLink: https://launchpad.net/bugs/1047261

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reported-by: Artemy Tregubenko <me@arty.name>
Tested-by: Artemy Tregubenko <me@arty.name>
Tested-by: Colin Ian King <colin.king@canonical.com>
(upstream cherry pick 7149f2558d5b5b988726662fe58b1c388337805b)
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 fs/ecryptfs/main.c |    1 +
 1 file changed, 1 insertion(+)
Brad Figg - Sept. 16, 2012, 6:07 a.m.
On 09/15/2012 12:09 PM, Colin King wrote:
> From: Tyler Hicks <tyhicks@canonical.com>
> 
> Fixes a regression caused by:
> 
> 821f749 eCryptfs: Revert to a writethrough cache model
> 
> That patch reverted some code (specifically, 32001d6f) that was
> necessary to properly handle open() -> mmap() -> close() -> dirty pages
> -> munmap(), because the lower file could be closed before the dirty
> pages are written out.
> 
> Rather than reapplying 32001d6f, this approach is a better way of
> ensuring that the lower file is still open in order to handle writing
> out the dirty pages. It is called from ecryptfs_release(), while we have
> a lock on the lower file pointer, just before the lower file gets the
> final fput() and we overwrite the pointer.
> 
> BugLink: https://launchpad.net/bugs/1047261
> 
> Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
> Reported-by: Artemy Tregubenko <me@arty.name>
> Tested-by: Artemy Tregubenko <me@arty.name>
> Tested-by: Colin Ian King <colin.king@canonical.com>
> (upstream cherry pick 7149f2558d5b5b988726662fe58b1c388337805b)
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  fs/ecryptfs/main.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
> index 2768138..9b627c1 100644
> --- a/fs/ecryptfs/main.c
> +++ b/fs/ecryptfs/main.c
> @@ -162,6 +162,7 @@ void ecryptfs_put_lower_file(struct inode *inode)
>  	inode_info = ecryptfs_inode_to_private(inode);
>  	if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
>  				      &inode_info->lower_file_mutex)) {
> +		filemap_write_and_wait(inode->i_mapping);
>  		fput(inode_info->lower_file);
>  		inode_info->lower_file = NULL;
>  		mutex_unlock(&inode_info->lower_file_mutex);
>

Patch

diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 2768138..9b627c1 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -162,6 +162,7 @@  void ecryptfs_put_lower_file(struct inode *inode)
 	inode_info = ecryptfs_inode_to_private(inode);
 	if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
 				      &inode_info->lower_file_mutex)) {
+		filemap_write_and_wait(inode->i_mapping);
 		fput(inode_info->lower_file);
 		inode_info->lower_file = NULL;
 		mutex_unlock(&inode_info->lower_file_mutex);