2013-12-11 10:45:29

by Christoph Hellwig

Subject: [PATCH 02/18] fs: add get_acl helper

Factor out the code to get an ACL either from the inode or disk from
check_acl, so that it can be used elsewhere later on.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
---
fs/namei.c | 24 +++---------------------
fs/posix_acl.c | 26 ++++++++++++++++++++++++++
include/linux/posix_acl.h | 2 ++
3 files changed, 31 insertions(+), 21 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index c53d3a9..8acd1e8 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -235,27 +235,9 @@ static int check_acl(struct inode *inode, int mask)
return posix_acl_permission(inode, acl, mask & ~MAY_NOT_BLOCK);
}

- acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
-
- /*
- * A filesystem can force a ACL callback by just never filling the
- * ACL cache. But normally you'd fill the cache either at inode
- * instantiation time, or on the first ->get_acl call.
- *
- * If the filesystem doesn't have a get_acl() function at all, we'll
- * just create the negative cache entry.
- */
- if (acl == ACL_NOT_CACHED) {
- if (inode->i_op->get_acl) {
- acl = inode->i_op->get_acl(inode, ACL_TYPE_ACCESS);
- if (IS_ERR(acl))
- return PTR_ERR(acl);
- } else {
- set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
- return -EAGAIN;
- }
- }
-
+ acl = get_acl(inode, ACL_TYPE_ACCESS);
+ if (IS_ERR(acl))
+ return PTR_ERR(acl);
if (acl) {
int error = posix_acl_permission(inode, acl, mask);
posix_acl_release(acl);
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 8bd2135..f2c48f8 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -418,3 +418,29 @@ posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode)
return err;
}
EXPORT_SYMBOL(posix_acl_chmod);
+
+struct posix_acl *get_acl(struct inode *inode, int type)
+{
+ struct posix_acl *acl;
+
+ acl = get_cached_acl(inode, type);
+ if (acl != ACL_NOT_CACHED)
+ return acl;
+
+ if (!IS_POSIXACL(inode))
+ return NULL;
+
+ /*
+ * A filesystem can force a ACL callback by just never filling the
+ * ACL cache. But normally you'd fill the cache either at inode
+ * instantiation time, or on the first ->get_acl call.
+ *
+ * If the filesystem doesn't have a get_acl() function at all, we'll
+ * just create the negative cache entry.
+ */
+ if (!inode->i_op->get_acl) {
+ set_cached_acl(inode, type, NULL);
+ return ERR_PTR(-EAGAIN);
+ }
+ return inode->i_op->get_acl(inode, type);
+}
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index 7931efe..a8d9918 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -175,4 +175,6 @@ static inline void cache_no_acl(struct inode *inode)
#endif
}

+struct posix_acl *get_acl(struct inode *inode, int type);
+
#endif /* __LINUX_POSIX_ACL_H */
--
1.7.10.4

2013-12-12 21:04:46

by Christoph Hellwig

Subject: Re: [PATCH 02/18] fs: add get_acl helper

On Thu, Dec 12, 2013 at 08:06:09PM +0100, Andreas Gruenbacher wrote:
> > + /*
> > + * A filesystem can force a ACL callback by just never filling the
> > + * ACL cache. But normally you'd fill the cache either at inode
> > + * instantiation time, or on the first ->get_acl call.
> > + *
> > + * If the filesystem doesn't have a get_acl() function at all, we'll
> > + * just create the negative cache entry.
> > + */
> > + if (!inode->i_op->get_acl) {
> > + set_cached_acl(inode, type, NULL);
> > + return ERR_PTR(-EAGAIN);
>
> The function should return NULL here.

Indeed. EAGAIN is the convention check_acl() in fs/namei.c uses,
but it will return that automatically if we just return NULL here.

2013-12-12 19:06:13

by Andreas Gruenbacher

Subject: Re: [PATCH 02/18] fs: add get_acl helper

Christoph,

> +struct posix_acl *get_acl(struct inode *inode, int type)
> +{
> + struct posix_acl *acl;
> +
> + acl = get_cached_acl(inode, type);
> + if (acl != ACL_NOT_CACHED)
> + return acl;
> +
> + if (!IS_POSIXACL(inode))
> + return NULL;
> +
> + /*
> + * A filesystem can force a ACL callback by just never filling the
> + * ACL cache. But normally you'd fill the cache either at inode
> + * instantiation time, or on the first ->get_acl call.
> + *
> + * If the filesystem doesn't have a get_acl() function at all, we'll
> + * just create the negative cache entry.
> + */
> + if (!inode->i_op->get_acl) {
> + set_cached_acl(inode, type, NULL);
> + return ERR_PTR(-EAGAIN);

The function should return NULL here.

Andreas