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18f4c64477
This avoids an indirect call in the VFS for each path component lookup. Well, at least as long as you own the directory in question, and the ACL check is unnecessary. Reviewed-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
458 lines
10 KiB
C
458 lines
10 KiB
C
/*
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* JFFS2 -- Journalling Flash File System, Version 2.
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*
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* Copyright © 2006 NEC Corporation
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*
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* Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
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*
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* For licensing information, see the file 'LICENCE' in this directory.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/sched.h>
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#include <linux/time.h>
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#include <linux/crc32.h>
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#include <linux/jffs2.h>
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#include <linux/xattr.h>
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#include <linux/posix_acl_xattr.h>
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#include <linux/mtd/mtd.h>
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#include "nodelist.h"
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static size_t jffs2_acl_size(int count)
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{
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if (count <= 4) {
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return sizeof(struct jffs2_acl_header)
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+ count * sizeof(struct jffs2_acl_entry_short);
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} else {
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return sizeof(struct jffs2_acl_header)
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+ 4 * sizeof(struct jffs2_acl_entry_short)
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+ (count - 4) * sizeof(struct jffs2_acl_entry);
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}
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}
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static int jffs2_acl_count(size_t size)
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{
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size_t s;
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size -= sizeof(struct jffs2_acl_header);
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if (size < 4 * sizeof(struct jffs2_acl_entry_short)) {
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if (size % sizeof(struct jffs2_acl_entry_short))
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return -1;
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return size / sizeof(struct jffs2_acl_entry_short);
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} else {
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s = size - 4 * sizeof(struct jffs2_acl_entry_short);
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if (s % sizeof(struct jffs2_acl_entry))
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return -1;
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return s / sizeof(struct jffs2_acl_entry) + 4;
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}
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}
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static struct posix_acl *jffs2_acl_from_medium(void *value, size_t size)
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{
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void *end = value + size;
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struct jffs2_acl_header *header = value;
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struct jffs2_acl_entry *entry;
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struct posix_acl *acl;
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uint32_t ver;
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int i, count;
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if (!value)
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return NULL;
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if (size < sizeof(struct jffs2_acl_header))
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return ERR_PTR(-EINVAL);
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ver = je32_to_cpu(header->a_version);
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if (ver != JFFS2_ACL_VERSION) {
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JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);
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return ERR_PTR(-EINVAL);
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}
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value += sizeof(struct jffs2_acl_header);
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count = jffs2_acl_count(size);
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if (count < 0)
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return ERR_PTR(-EINVAL);
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if (count == 0)
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return NULL;
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acl = posix_acl_alloc(count, GFP_KERNEL);
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if (!acl)
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return ERR_PTR(-ENOMEM);
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for (i=0; i < count; i++) {
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entry = value;
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if (value + sizeof(struct jffs2_acl_entry_short) > end)
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goto fail;
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acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag);
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acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm);
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switch (acl->a_entries[i].e_tag) {
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case ACL_USER_OBJ:
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case ACL_GROUP_OBJ:
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case ACL_MASK:
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case ACL_OTHER:
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value += sizeof(struct jffs2_acl_entry_short);
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acl->a_entries[i].e_id = ACL_UNDEFINED_ID;
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break;
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case ACL_USER:
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case ACL_GROUP:
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value += sizeof(struct jffs2_acl_entry);
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if (value > end)
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goto fail;
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acl->a_entries[i].e_id = je32_to_cpu(entry->e_id);
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break;
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default:
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goto fail;
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}
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}
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if (value != end)
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goto fail;
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return acl;
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fail:
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posix_acl_release(acl);
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return ERR_PTR(-EINVAL);
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}
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static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
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{
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struct jffs2_acl_header *header;
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struct jffs2_acl_entry *entry;
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void *e;
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size_t i;
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*size = jffs2_acl_size(acl->a_count);
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header = kmalloc(sizeof(*header) + acl->a_count * sizeof(*entry), GFP_KERNEL);
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if (!header)
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return ERR_PTR(-ENOMEM);
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header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
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e = header + 1;
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for (i=0; i < acl->a_count; i++) {
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entry = e;
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entry->e_tag = cpu_to_je16(acl->a_entries[i].e_tag);
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entry->e_perm = cpu_to_je16(acl->a_entries[i].e_perm);
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switch(acl->a_entries[i].e_tag) {
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case ACL_USER:
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case ACL_GROUP:
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entry->e_id = cpu_to_je32(acl->a_entries[i].e_id);
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e += sizeof(struct jffs2_acl_entry);
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break;
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case ACL_USER_OBJ:
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case ACL_GROUP_OBJ:
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case ACL_MASK:
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case ACL_OTHER:
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e += sizeof(struct jffs2_acl_entry_short);
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break;
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default:
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goto fail;
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}
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}
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return header;
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fail:
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kfree(header);
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return ERR_PTR(-EINVAL);
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}
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static struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
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{
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struct posix_acl *acl;
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char *value = NULL;
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int rc, xprefix;
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acl = get_cached_acl(inode, type);
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if (acl != ACL_NOT_CACHED)
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return acl;
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switch (type) {
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case ACL_TYPE_ACCESS:
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xprefix = JFFS2_XPREFIX_ACL_ACCESS;
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break;
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case ACL_TYPE_DEFAULT:
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xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
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break;
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default:
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BUG();
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}
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rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
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if (rc > 0) {
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value = kmalloc(rc, GFP_KERNEL);
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if (!value)
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return ERR_PTR(-ENOMEM);
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rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
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}
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if (rc > 0) {
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acl = jffs2_acl_from_medium(value, rc);
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} else if (rc == -ENODATA || rc == -ENOSYS) {
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acl = NULL;
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} else {
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acl = ERR_PTR(rc);
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}
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if (value)
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kfree(value);
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if (!IS_ERR(acl))
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set_cached_acl(inode, type, acl);
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return acl;
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}
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static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl)
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{
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char *value = NULL;
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size_t size = 0;
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int rc;
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if (acl) {
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value = jffs2_acl_to_medium(acl, &size);
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if (IS_ERR(value))
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return PTR_ERR(value);
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}
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rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
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if (!value && rc == -ENODATA)
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rc = 0;
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kfree(value);
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return rc;
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}
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static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
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{
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int rc, xprefix;
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if (S_ISLNK(inode->i_mode))
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return -EOPNOTSUPP;
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switch (type) {
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case ACL_TYPE_ACCESS:
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xprefix = JFFS2_XPREFIX_ACL_ACCESS;
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if (acl) {
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mode_t mode = inode->i_mode;
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rc = posix_acl_equiv_mode(acl, &mode);
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if (rc < 0)
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return rc;
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if (inode->i_mode != mode) {
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struct iattr attr;
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attr.ia_valid = ATTR_MODE;
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attr.ia_mode = mode;
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rc = jffs2_do_setattr(inode, &attr);
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if (rc < 0)
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return rc;
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}
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if (rc == 0)
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acl = NULL;
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}
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break;
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case ACL_TYPE_DEFAULT:
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xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
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if (!S_ISDIR(inode->i_mode))
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return acl ? -EACCES : 0;
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break;
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default:
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return -EINVAL;
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}
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rc = __jffs2_set_acl(inode, xprefix, acl);
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if (!rc)
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set_cached_acl(inode, type, acl);
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return rc;
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}
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int jffs2_check_acl(struct inode *inode, int mask)
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{
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struct posix_acl *acl;
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int rc;
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acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
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if (IS_ERR(acl))
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return PTR_ERR(acl);
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if (acl) {
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rc = posix_acl_permission(inode, acl, mask);
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posix_acl_release(acl);
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return rc;
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}
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return -EAGAIN;
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}
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int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, int *i_mode)
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{
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struct posix_acl *acl, *clone;
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int rc;
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cache_no_acl(inode);
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if (S_ISLNK(*i_mode))
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return 0; /* Symlink always has no-ACL */
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acl = jffs2_get_acl(dir_i, ACL_TYPE_DEFAULT);
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if (IS_ERR(acl))
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return PTR_ERR(acl);
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if (!acl) {
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*i_mode &= ~current_umask();
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} else {
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if (S_ISDIR(*i_mode))
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set_cached_acl(inode, ACL_TYPE_DEFAULT, acl);
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clone = posix_acl_clone(acl, GFP_KERNEL);
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if (!clone)
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return -ENOMEM;
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rc = posix_acl_create_masq(clone, (mode_t *)i_mode);
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if (rc < 0) {
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posix_acl_release(clone);
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return rc;
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}
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if (rc > 0)
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set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
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posix_acl_release(clone);
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}
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return 0;
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}
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int jffs2_init_acl_post(struct inode *inode)
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{
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int rc;
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if (inode->i_default_acl) {
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rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
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if (rc)
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return rc;
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}
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if (inode->i_acl) {
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rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
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if (rc)
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return rc;
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}
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return 0;
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}
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int jffs2_acl_chmod(struct inode *inode)
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{
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struct posix_acl *acl, *clone;
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int rc;
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if (S_ISLNK(inode->i_mode))
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return -EOPNOTSUPP;
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acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
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if (IS_ERR(acl) || !acl)
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return PTR_ERR(acl);
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clone = posix_acl_clone(acl, GFP_KERNEL);
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posix_acl_release(acl);
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if (!clone)
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return -ENOMEM;
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rc = posix_acl_chmod_masq(clone, inode->i_mode);
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if (!rc)
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rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
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posix_acl_release(clone);
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return rc;
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}
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static size_t jffs2_acl_access_listxattr(struct inode *inode, char *list, size_t list_size,
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const char *name, size_t name_len)
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{
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const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);
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if (list && retlen <= list_size)
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strcpy(list, POSIX_ACL_XATTR_ACCESS);
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return retlen;
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}
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static size_t jffs2_acl_default_listxattr(struct inode *inode, char *list, size_t list_size,
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const char *name, size_t name_len)
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{
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const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);
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if (list && retlen <= list_size)
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strcpy(list, POSIX_ACL_XATTR_DEFAULT);
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return retlen;
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}
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static int jffs2_acl_getxattr(struct inode *inode, int type, void *buffer, size_t size)
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{
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struct posix_acl *acl;
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int rc;
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acl = jffs2_get_acl(inode, type);
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if (IS_ERR(acl))
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return PTR_ERR(acl);
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if (!acl)
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return -ENODATA;
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rc = posix_acl_to_xattr(acl, buffer, size);
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posix_acl_release(acl);
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return rc;
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}
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static int jffs2_acl_access_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
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{
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if (name[0] != '\0')
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return -EINVAL;
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return jffs2_acl_getxattr(inode, ACL_TYPE_ACCESS, buffer, size);
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}
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static int jffs2_acl_default_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
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{
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if (name[0] != '\0')
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return -EINVAL;
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return jffs2_acl_getxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
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}
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static int jffs2_acl_setxattr(struct inode *inode, int type, const void *value, size_t size)
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{
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struct posix_acl *acl;
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int rc;
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if (!is_owner_or_cap(inode))
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return -EPERM;
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if (value) {
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acl = posix_acl_from_xattr(value, size);
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if (IS_ERR(acl))
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return PTR_ERR(acl);
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if (acl) {
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rc = posix_acl_valid(acl);
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if (rc)
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goto out;
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}
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} else {
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acl = NULL;
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}
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rc = jffs2_set_acl(inode, type, acl);
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out:
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posix_acl_release(acl);
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return rc;
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}
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static int jffs2_acl_access_setxattr(struct inode *inode, const char *name,
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const void *buffer, size_t size, int flags)
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{
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if (name[0] != '\0')
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return -EINVAL;
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return jffs2_acl_setxattr(inode, ACL_TYPE_ACCESS, buffer, size);
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}
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static int jffs2_acl_default_setxattr(struct inode *inode, const char *name,
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const void *buffer, size_t size, int flags)
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{
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if (name[0] != '\0')
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return -EINVAL;
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return jffs2_acl_setxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
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}
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struct xattr_handler jffs2_acl_access_xattr_handler = {
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.prefix = POSIX_ACL_XATTR_ACCESS,
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.list = jffs2_acl_access_listxattr,
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.get = jffs2_acl_access_getxattr,
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.set = jffs2_acl_access_setxattr,
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};
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struct xattr_handler jffs2_acl_default_xattr_handler = {
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.prefix = POSIX_ACL_XATTR_DEFAULT,
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.list = jffs2_acl_default_listxattr,
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.get = jffs2_acl_default_getxattr,
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.set = jffs2_acl_default_setxattr,
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};
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