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vfs: move ACL cache lookup into generic code

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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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

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);