Re: [PATCH] ecryptfs: some inode attrs, and a question

From: Andrew Morton
Date: Thu Jan 15 2009 - 18:05:48 EST


On Tue, 13 Jan 2009 15:20:21 +0900
hooanon05@xxxxxxxxxxx wrote:

>
> Here are several fixes for linux-2.6.27/fs/ecryptfs.
>
> - The ecryptfs inode holds a reference to the lower inode, but doesn't
> increment the reference counter. When a user sets inotify to the
> ecryptfs inode, it may live without the corresponding dentry. In this
> case the referecen to the lower inode may be broken.
> This patch maintains the reference of the lower inode.
>
> - follow the VFS unlink sequence in ecryptfs_unlink() which is
> inrementing and decrementing the inode->i_count and the reference
> counter for the dentry.
>
> - maintain the link count and ctime in ecryptfs_rmdir() because a user
> may issue fstat(2) later.
>
> - remove the unnecessary d_drop()s in ecryptfs_link().
>
> And I have experienced a strange behaviour. When ecryptfs gets -ENOSPC
> from the lower fs, it converts and returns EINVAL to the userspace. Is
> this an intended behaviour?
>

I am puzzled by the current ecryptfs maintenance situation.

I queued this for 2.6.30. It could be bumped up for 2.6.29 (and even
backported to 2.6.28 and earlier) with suitable acks from the
maintainer(?)

>
> ...
>
> + atomic_inc_return(&lower_dentry->d_inode->i_count);
> + atomic_inc_return(&lower_inode->i_count);

atomic_inc() would suffice here, yes?

From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>

s/atomic_inc_return/atomic_inc/

Cc: Dave Kleikamp <shaggy@xxxxxxxxxxxxxxxxxx>
Cc: J. R. Okajima <hooanon05@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

fs/ecryptfs/inode.c | 2 +-
fs/ecryptfs/super.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff -puN fs/ecryptfs/inode.c~ecryptfs-some-inode-attr-fixes-fix fs/ecryptfs/inode.c
--- a/fs/ecryptfs/inode.c~ecryptfs-some-inode-attr-fixes-fix
+++ a/fs/ecryptfs/inode.c
@@ -479,7 +479,7 @@ static int ecryptfs_unlink(struct inode

lower_dir_dentry = lock_parent(lower_dentry);
dget(lower_dentry);
- atomic_inc_return(&lower_dentry->d_inode->i_count);
+ atomic_inc(&lower_dentry->d_inode->i_count);
rc = vfs_unlink(lower_dir_inode, lower_dentry);
dput(lower_dentry);
if (rc) {
diff -puN fs/ecryptfs/super.c~ecryptfs-some-inode-attr-fixes-fix fs/ecryptfs/super.c
--- a/fs/ecryptfs/super.c~ecryptfs-some-inode-attr-fixes-fix
+++ a/fs/ecryptfs/super.c
@@ -102,7 +102,7 @@ static void ecryptfs_destroy_inode(struc
*/
void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode)
{
- atomic_inc_return(&lower_inode->i_count);
+ atomic_inc(&lower_inode->i_count);
ecryptfs_set_inode_lower(inode, lower_inode);
inode->i_ino = lower_inode->i_ino;
inode->i_version++;
_

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