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vfs: move ACL cache lookup into generic code 

This moves logic for checking the cached ACL values from low-level
filesystems into generic code.  The end result is a streamlined ACL
check that doesn't need to load the inode->i_op->check_acl pointer at
all for the common cached case.

The filesystems also don't need to check for a non-blocking RCU walk
case in their acl_check() functions, because that is all handled at a
VFS layer.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Linus Torvalds 2011-07-22 19:30:19 -07:00 committed by Al Viro
parent 3ca30d40a9
commit e77819e57f
12 changed files with 64 additions and 68 deletions
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3
fs/9p/acl.c
View File

@ -101,9 +101,6 @@ int v9fs_check_acl(struct inode *inode, int mask)
struct posix_acl *acl;
struct v9fs_session_info *v9ses;
if (mask & MAY_NOT_BLOCK)
return -ECHILD;
v9ses = v9fs_inode2v9ses(inode);
if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {

19
fs/btrfs/acl.c
View File

@ -198,19 +198,14 @@ out:
int btrfs_check_acl(struct inode *inode, int mask)
{
int error = -EAGAIN;
struct posix_acl *acl;
if (mask & MAY_NOT_BLOCK) {
if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
error = -ECHILD;
} else {
struct posix_acl *acl;
acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl) {
error = posix_acl_permission(inode, acl, mask);
posix_acl_release(acl);
}
acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl) {
error = posix_acl_permission(inode, acl, mask);
posix_acl_release(acl);
}
return error;

6
fs/ext2/acl.c
View File

@ -236,12 +236,6 @@ ext2_check_acl(struct inode *inode, int mask)
{
struct posix_acl *acl;
if (mask & MAY_NOT_BLOCK) {
if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
return -ECHILD;
return -EAGAIN;
}
acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);

6
fs/ext3/acl.c
View File

@ -244,12 +244,6 @@ ext3_check_acl(struct inode *inode, int mask)
{
struct posix_acl *acl;
if (mask & MAY_NOT_BLOCK) {
if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
return -ECHILD;
return -EAGAIN;
}
acl = ext3_get_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);

6
fs/ext4/acl.c
View File

@ -242,12 +242,6 @@ ext4_check_acl(struct inode *inode, int mask)
{
struct posix_acl *acl;
if (mask & MAY_NOT_BLOCK) {
if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
return -ECHILD;
return -EAGAIN;
}
acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);

17
fs/generic_acl.c
View File

@ -192,18 +192,13 @@ generic_acl_chmod(struct inode *inode)
int
generic_check_acl(struct inode *inode, int mask)
{
if (mask & MAY_NOT_BLOCK) {
if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
return -ECHILD;
} else {
struct posix_acl *acl;
struct posix_acl *acl;
acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
if (acl) {
int error = posix_acl_permission(inode, acl, mask);
posix_acl_release(acl);
return error;
}
acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
if (acl) {
int error = posix_acl_permission(inode, acl, mask);
posix_acl_release(acl);
return error;
}
return -EAGAIN;
}

6
fs/gfs2/acl.c
View File

@ -80,12 +80,6 @@ int gfs2_check_acl(struct inode *inode, int mask)
struct posix_acl *acl;
int error;
if (mask & MAY_NOT_BLOCK) {
if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
return -ECHILD;
return -EAGAIN;
}
acl = gfs2_acl_get(GFS2_I(inode), ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);

3
fs/jffs2/acl.c
View File

@ -264,9 +264,6 @@ int jffs2_check_acl(struct inode *inode, int mask)
struct posix_acl *acl;
int rc;
if (mask & MAY_NOT_BLOCK)
return -ECHILD;
acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);

3
fs/jfs/acl.c
View File

@ -118,9 +118,6 @@ int jfs_check_acl(struct inode *inode, int mask)
{
struct posix_acl *acl;
if (mask & MAY_NOT_BLOCK)
return -ECHILD;
acl = jfs_get_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);

52
fs/namei.c
View File

@ -32,6 +32,7 @@
#include <linux/fcntl.h>
#include <linux/device_cgroup.h>
#include <linux/fs_struct.h>
#include <linux/posix_acl.h>
#include <asm/uaccess.h>
#include "internal.h"
@ -173,12 +174,58 @@ void putname(const char *name)
EXPORT_SYMBOL(putname);
#endif
static int check_acl(struct inode *inode, int mask)
{
struct posix_acl *acl;
/*
* Under RCU walk, we cannot even do a "get_cached_acl()",
* because that involves locking and getting a refcount on
* a cached ACL.
*
* So the only case we handle during RCU walking is the
* case of a cached "no ACL at all", which needs no locks
* or refcounts.
*/
if (mask & MAY_NOT_BLOCK) {
if (negative_cached_acl(inode, ACL_TYPE_ACCESS))
return -EAGAIN;
return -ECHILD;
}
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 ->check_acl call.
*
* If the filesystem doesn't have a check_acl() function
* at all, we'll just create the negative cache entry.
*/
if (acl == ACL_NOT_CACHED) {
if (inode->i_op->check_acl)
return inode->i_op->check_acl(inode, mask);
set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
return -EAGAIN;
}
if (acl) {
int error = posix_acl_permission(inode, acl, mask);
posix_acl_release(acl);
return error;
}
return -EAGAIN;
}
/*
* This does basic POSIX ACL permission checking
*/
static int acl_permission_check(struct inode *inode, int mask)
{
int (*check_acl)(struct inode *inode, int mask);
unsigned int mode = inode->i_mode;
mask &= MAY_READ | MAY_WRITE | MAY_EXEC | MAY_NOT_BLOCK;
@ -189,8 +236,7 @@ static int acl_permission_check(struct inode *inode, int mask)
if (current_fsuid() == inode->i_uid)
mode >>= 6;
else {
check_acl = inode->i_op->check_acl;
if (IS_POSIXACL(inode) && (mode & S_IRWXG) && check_acl) {
if (IS_POSIXACL(inode) && (mode & S_IRWXG)) {
int error = check_acl(inode, mask);
if (error != -EAGAIN)
return error;

3
fs/ocfs2/acl.c
View File

@ -297,9 +297,6 @@ int ocfs2_check_acl(struct inode *inode, int mask)
struct posix_acl *acl;
int ret = -EAGAIN;
if (mask & MAY_NOT_BLOCK)
return -ECHILD;
osb = OCFS2_SB(inode->i_sb);
if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
return ret;

8
fs/xfs/linux-2.6/xfs_acl.c
View File

@ -231,16 +231,12 @@ xfs_check_acl(struct inode *inode, int mask)
/*
* If there is no attribute fork no ACL exists on this inode and
* we can skip the whole exercise.
*
* FIXME! Fill the cache! Locking?
*/
if (!XFS_IFORK_Q(ip))
return -EAGAIN;
if (mask & MAY_NOT_BLOCK) {
if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
return -ECHILD;
return -EAGAIN;
}
acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);