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authorMiklos Szeredi <mszeredi@redhat.com>2021-08-18 23:08:24 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2021-08-18 23:08:24 +0300
commit332f606b32b6291a944c8cf23b91f53a6e676525 (patch)
treec3a46cae0901eec40dd900a9a64c8ad1e51647ba /include/linux/posix_acl.h
parent0cad6246621b5887d5b33fea84219d2a71f2f99a (diff)
downloadlinux-332f606b32b6291a944c8cf23b91f53a6e676525.tar.xz
ovl: enable RCU'd ->get_acl()
Overlayfs does not cache ACL's (to avoid double caching). Instead it just calls the underlying filesystem's i_op->get_acl(), which will return the cached value, if possible. In rcu path walk, however, get_cached_acl_rcu() is employed to get the value from the cache, which will fail on overlayfs resulting in dropping out of rcu walk mode. This can result in a big performance hit in certain situations. Fix by calling ->get_acl() with rcu=true in case of ACL_DONT_CACHE (which indicates pass-through) Reported-by: garyhuang <zjh.20052005@163.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'include/linux/posix_acl.h')
-rw-r--r--include/linux/posix_acl.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index 307094ebb88c..b65c877d92b8 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -72,6 +72,8 @@ extern struct posix_acl *get_posix_acl(struct inode *, int);
extern int set_posix_acl(struct user_namespace *, struct inode *, int,
struct posix_acl *);
+struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type);
+
#ifdef CONFIG_FS_POSIX_ACL
int posix_acl_chmod(struct user_namespace *, struct inode *, umode_t);
extern int posix_acl_create(struct inode *, umode_t *, struct posix_acl **,
@@ -84,7 +86,6 @@ extern int simple_set_acl(struct user_namespace *, struct inode *,
extern int simple_acl_create(struct inode *, struct inode *);
struct posix_acl *get_cached_acl(struct inode *inode, int type);
-struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type);
void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl);
void forget_cached_acl(struct inode *inode, int type);
void forget_all_cached_acls(struct inode *inode);