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make generic_acl slightly more generic
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Now that we cache the ACL pointers in the generic inode all the generic_acl
cruft can go away and generic_acl.c can directly implement xattr handlers
dealing with the full Posix ACL semantics for in-memory filesystems.

Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Al Viro <[email protected]>
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Christoph Hellwig authored and Al Viro committed Dec 16, 2009
1 parent 431547b commit 1c7c474
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Showing 6 changed files with 109 additions and 257 deletions.
158 changes: 89 additions & 69 deletions fs/generic_acl.c
View file
Original file line number Diff line number Diff line change
@@ -1,62 +1,58 @@
/*
* fs/generic_acl.c
*
* (C) 2005 Andreas Gruenbacher <[email protected]>
*
* This file is released under the GPL.
*
* Generic ACL support for in-memory filesystems.
*/

#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/generic_acl.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>

/**
* generic_acl_list - Generic xattr_handler->list() operation
* @ops: Filesystem specific getacl and setacl callbacks
*/
size_t
generic_acl_list(struct inode *inode, struct generic_acl_operations *ops,
int type, char *list, size_t list_size)

static size_t
generic_acl_list(struct dentry *dentry, char *list, size_t list_size,
const char *name, size_t name_len, int type)
{
struct posix_acl *acl;
const char *name;
const char *xname;
size_t size;

acl = ops->getacl(inode, type);
acl = get_cached_acl(dentry->d_inode, type);
if (!acl)
return 0;
posix_acl_release(acl);

switch(type) {
case ACL_TYPE_ACCESS:
name = POSIX_ACL_XATTR_ACCESS;
break;

case ACL_TYPE_DEFAULT:
name = POSIX_ACL_XATTR_DEFAULT;
break;

default:
return 0;
switch (type) {
case ACL_TYPE_ACCESS:
xname = POSIX_ACL_XATTR_ACCESS;
break;
case ACL_TYPE_DEFAULT:
xname = POSIX_ACL_XATTR_DEFAULT;
break;
default:
return 0;
}
size = strlen(name) + 1;
size = strlen(xname) + 1;
if (list && size <= list_size)
memcpy(list, name, size);
memcpy(list, xname, size);
return size;
}

/**
* generic_acl_get - Generic xattr_handler->get() operation
* @ops: Filesystem specific getacl and setacl callbacks
*/
int
generic_acl_get(struct inode *inode, struct generic_acl_operations *ops,
int type, void *buffer, size_t size)
static int
generic_acl_get(struct dentry *dentry, const char *name, void *buffer,
size_t size, int type)
{
struct posix_acl *acl;
int error;

acl = ops->getacl(inode, type);
if (strcmp(name, "") != 0)
return -EINVAL;

acl = get_cached_acl(dentry->d_inode, type);
if (!acl)
return -ENODATA;
error = posix_acl_to_xattr(acl, buffer, size);
Expand All @@ -65,17 +61,16 @@ generic_acl_get(struct inode *inode, struct generic_acl_operations *ops,
return error;
}

/**
* generic_acl_set - Generic xattr_handler->set() operation
* @ops: Filesystem specific getacl and setacl callbacks
*/
int
generic_acl_set(struct inode *inode, struct generic_acl_operations *ops,
int type, const void *value, size_t size)
static int
generic_acl_set(struct dentry *dentry, const char *name, const void *value,
size_t size, int flags, int type)
{
struct inode *inode = dentry->d_inode;
struct posix_acl *acl = NULL;
int error;

if (strcmp(name, "") != 0)
return -EINVAL;
if (S_ISLNK(inode->i_mode))
return -EOPNOTSUPP;
if (!is_owner_or_cap(inode))
Expand All @@ -91,28 +86,27 @@ generic_acl_set(struct inode *inode, struct generic_acl_operations *ops,
error = posix_acl_valid(acl);
if (error)
goto failed;
switch(type) {
case ACL_TYPE_ACCESS:
mode = inode->i_mode;
error = posix_acl_equiv_mode(acl, &mode);
if (error < 0)
goto failed;
inode->i_mode = mode;
if (error == 0) {
posix_acl_release(acl);
acl = NULL;
}
break;

case ACL_TYPE_DEFAULT:
if (!S_ISDIR(inode->i_mode)) {
error = -EINVAL;
goto failed;
}
break;
switch (type) {
case ACL_TYPE_ACCESS:
mode = inode->i_mode;
error = posix_acl_equiv_mode(acl, &mode);
if (error < 0)
goto failed;
inode->i_mode = mode;
if (error == 0) {
posix_acl_release(acl);
acl = NULL;
}
break;
case ACL_TYPE_DEFAULT:
if (!S_ISDIR(inode->i_mode)) {
error = -EINVAL;
goto failed;
}
break;
}
}
ops->setacl(inode, type, acl);
set_cached_acl(inode, type, acl);
error = 0;
failed:
posix_acl_release(acl);
Expand All @@ -121,22 +115,20 @@ generic_acl_set(struct inode *inode, struct generic_acl_operations *ops,

/**
* generic_acl_init - Take care of acl inheritance at @inode create time
* @ops: Filesystem specific getacl and setacl callbacks
*
* Files created inside a directory with a default ACL inherit the
* directory's default ACL.
*/
int
generic_acl_init(struct inode *inode, struct inode *dir,
struct generic_acl_operations *ops)
generic_acl_init(struct inode *inode, struct inode *dir)
{
struct posix_acl *acl = NULL;
mode_t mode = inode->i_mode;
int error;

inode->i_mode = mode & ~current_umask();
if (!S_ISLNK(inode->i_mode))
acl = ops->getacl(dir, ACL_TYPE_DEFAULT);
acl = get_cached_acl(dir, ACL_TYPE_DEFAULT);
if (acl) {
struct posix_acl *clone;

Expand All @@ -145,7 +137,7 @@ generic_acl_init(struct inode *inode, struct inode *dir,
error = -ENOMEM;
if (!clone)
goto cleanup;
ops->setacl(inode, ACL_TYPE_DEFAULT, clone);
set_cached_acl(inode, ACL_TYPE_DEFAULT, clone);
posix_acl_release(clone);
}
clone = posix_acl_clone(acl, GFP_KERNEL);
Expand All @@ -156,7 +148,7 @@ generic_acl_init(struct inode *inode, struct inode *dir,
if (error >= 0) {
inode->i_mode = mode;
if (error > 0)
ops->setacl(inode, ACL_TYPE_ACCESS, clone);
set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
}
posix_acl_release(clone);
}
Expand All @@ -169,29 +161,57 @@ generic_acl_init(struct inode *inode, struct inode *dir,

/**
* generic_acl_chmod - change the access acl of @inode upon chmod()
* @ops: FIlesystem specific getacl and setacl callbacks
*
* A chmod also changes the permissions of the owner, group/mask, and
* other ACL entries.
*/
int
generic_acl_chmod(struct inode *inode, struct generic_acl_operations *ops)
generic_acl_chmod(struct inode *inode)
{
struct posix_acl *acl, *clone;
int error = 0;

if (S_ISLNK(inode->i_mode))
return -EOPNOTSUPP;
acl = ops->getacl(inode, ACL_TYPE_ACCESS);
acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
if (acl) {
clone = posix_acl_clone(acl, GFP_KERNEL);
posix_acl_release(acl);
if (!clone)
return -ENOMEM;
error = posix_acl_chmod_masq(clone, inode->i_mode);
if (!error)
ops->setacl(inode, ACL_TYPE_ACCESS, clone);
set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
posix_acl_release(clone);
}
return error;
}

int
generic_check_acl(struct inode *inode, int mask)
{
struct posix_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;
}
return -EAGAIN;
}

struct xattr_handler generic_acl_access_handler = {
.prefix = POSIX_ACL_XATTR_ACCESS,
.flags = ACL_TYPE_ACCESS,
.list = generic_acl_list,
.get = generic_acl_get,
.set = generic_acl_set,
};

struct xattr_handler generic_acl_default_handler = {
.prefix = POSIX_ACL_XATTR_DEFAULT,
.flags = ACL_TYPE_DEFAULT,
.list = generic_acl_list,
.get = generic_acl_get,
.set = generic_acl_set,
};
41 changes: 10 additions & 31 deletions include/linux/generic_acl.h
View file
Original file line number Diff line number Diff line change
@@ -1,36 +1,15 @@
/*
* include/linux/generic_acl.h
*
* (C) 2005 Andreas Gruenbacher <[email protected]>
*
* This file is released under the GPL.
*/
#ifndef LINUX_GENERIC_ACL_H
#define LINUX_GENERIC_ACL_H

#ifndef GENERIC_ACL_H
#define GENERIC_ACL_H
#include <linux/xattr.h>

#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
struct inode;

/**
* struct generic_acl_operations - filesystem operations
*
* Filesystems must make these operations available to the generic
* operations.
*/
struct generic_acl_operations {
struct posix_acl *(*getacl)(struct inode *, int);
void (*setacl)(struct inode *, int, struct posix_acl *);
};
extern struct xattr_handler generic_acl_access_handler;
extern struct xattr_handler generic_acl_default_handler;

size_t generic_acl_list(struct inode *, struct generic_acl_operations *, int,
char *, size_t);
int generic_acl_get(struct inode *, struct generic_acl_operations *, int,
void *, size_t);
int generic_acl_set(struct inode *, struct generic_acl_operations *, int,
const void *, size_t);
int generic_acl_init(struct inode *, struct inode *,
struct generic_acl_operations *);
int generic_acl_chmod(struct inode *, struct generic_acl_operations *);
int generic_acl_init(struct inode *, struct inode *);
int generic_acl_chmod(struct inode *);
int generic_check_acl(struct inode *inode, int mask);

#endif
#endif /* LINUX_GENERIC_ACL_H */
16 changes: 0 additions & 16 deletions include/linux/shmem_fs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -41,20 +41,4 @@ static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
extern int init_tmpfs(void);
extern int shmem_fill_super(struct super_block *sb, void *data, int silent);

#ifdef CONFIG_TMPFS_POSIX_ACL
int shmem_check_acl(struct inode *, int);
int shmem_acl_init(struct inode *, struct inode *);

extern struct xattr_handler shmem_xattr_acl_access_handler;
extern struct xattr_handler shmem_xattr_acl_default_handler;

extern struct generic_acl_operations shmem_acl_ops;

#else
static inline int shmem_acl_init(struct inode *inode, struct inode *dir)
{
return 0;
}
#endif /* CONFIG_TMPFS_POSIX_ACL */

#endif
1 change: 0 additions & 1 deletion mm/Makefile
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,6 @@ obj-$(CONFIG_HUGETLBFS) += hugetlb.o
obj-$(CONFIG_NUMA) += mempolicy.o
obj-$(CONFIG_SPARSEMEM) += sparse.o
obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o
obj-$(CONFIG_TMPFS_POSIX_ACL) += shmem_acl.o
obj-$(CONFIG_SLOB) += slob.o
obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o
obj-$(CONFIG_KSM) += ksm.o
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