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![Christoph Hellwig](/assets/img/avatar_default.png)
No need to allocate the max size if we can just allocate the easily known actual ACL size. Suggested-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
283 lines
5.9 KiB
C
283 lines
5.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2008, Christoph Hellwig
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* All Rights Reserved.
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*/
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#include "xfs.h"
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#include "xfs_shared.h"
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#include "xfs_format.h"
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#include "xfs_log_format.h"
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#include "xfs_trans_resv.h"
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#include "xfs_mount.h"
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#include "xfs_inode.h"
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#include "xfs_attr.h"
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#include "xfs_trace.h"
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#include "xfs_error.h"
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#include "xfs_acl.h"
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#include "xfs_da_format.h"
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#include "xfs_da_btree.h"
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#include <linux/posix_acl_xattr.h>
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/*
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* Locking scheme:
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* - all ACL updates are protected by inode->i_mutex, which is taken before
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* calling into this file.
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*/
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STATIC struct posix_acl *
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xfs_acl_from_disk(
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struct xfs_mount *mp,
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const struct xfs_acl *aclp,
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int len,
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int max_entries)
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{
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struct posix_acl_entry *acl_e;
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struct posix_acl *acl;
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const struct xfs_acl_entry *ace;
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unsigned int count, i;
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if (len < sizeof(*aclp)) {
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XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
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len);
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return ERR_PTR(-EFSCORRUPTED);
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}
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count = be32_to_cpu(aclp->acl_cnt);
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if (count > max_entries || XFS_ACL_SIZE(count) != len) {
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XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
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len);
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return ERR_PTR(-EFSCORRUPTED);
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}
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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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acl_e = &acl->a_entries[i];
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ace = &aclp->acl_entry[i];
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/*
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* The tag is 32 bits on disk and 16 bits in core.
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*
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* Because every access to it goes through the core
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* format first this is not a problem.
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*/
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acl_e->e_tag = be32_to_cpu(ace->ae_tag);
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acl_e->e_perm = be16_to_cpu(ace->ae_perm);
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switch (acl_e->e_tag) {
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case ACL_USER:
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acl_e->e_uid = make_kuid(&init_user_ns,
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be32_to_cpu(ace->ae_id));
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break;
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case ACL_GROUP:
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acl_e->e_gid = make_kgid(&init_user_ns,
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be32_to_cpu(ace->ae_id));
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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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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 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
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xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
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{
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const struct posix_acl_entry *acl_e;
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struct xfs_acl_entry *ace;
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int i;
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aclp->acl_cnt = cpu_to_be32(acl->a_count);
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for (i = 0; i < acl->a_count; i++) {
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ace = &aclp->acl_entry[i];
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acl_e = &acl->a_entries[i];
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ace->ae_tag = cpu_to_be32(acl_e->e_tag);
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switch (acl_e->e_tag) {
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case ACL_USER:
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ace->ae_id = cpu_to_be32(
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from_kuid(&init_user_ns, acl_e->e_uid));
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break;
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case ACL_GROUP:
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ace->ae_id = cpu_to_be32(
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from_kgid(&init_user_ns, acl_e->e_gid));
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break;
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default:
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ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
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break;
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}
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ace->ae_perm = cpu_to_be16(acl_e->e_perm);
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}
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}
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struct posix_acl *
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xfs_get_acl(struct inode *inode, int type)
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{
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struct xfs_inode *ip = XFS_I(inode);
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struct xfs_mount *mp = ip->i_mount;
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struct posix_acl *acl = NULL;
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struct xfs_da_args args = {
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.dp = ip,
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.attr_filter = XFS_ATTR_ROOT,
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.valuelen = XFS_ACL_MAX_SIZE(mp),
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};
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int error;
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trace_xfs_get_acl(ip);
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switch (type) {
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case ACL_TYPE_ACCESS:
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args.name = SGI_ACL_FILE;
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break;
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case ACL_TYPE_DEFAULT:
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args.name = SGI_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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args.namelen = strlen(args.name);
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/*
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* If the attribute doesn't exist make sure we have a negative cache
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* entry, for any other error assume it is transient.
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*/
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error = xfs_attr_get(&args);
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if (!error) {
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acl = xfs_acl_from_disk(mp, args.value, args.valuelen,
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XFS_ACL_MAX_ENTRIES(mp));
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} else if (error != -ENOATTR) {
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acl = ERR_PTR(error);
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}
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kmem_free(args.value);
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return acl;
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}
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int
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__xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
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{
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struct xfs_inode *ip = XFS_I(inode);
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struct xfs_da_args args = {
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.dp = ip,
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.attr_filter = XFS_ATTR_ROOT,
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};
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int error;
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switch (type) {
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case ACL_TYPE_ACCESS:
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args.name = SGI_ACL_FILE;
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break;
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case ACL_TYPE_DEFAULT:
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if (!S_ISDIR(inode->i_mode))
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return acl ? -EACCES : 0;
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args.name = SGI_ACL_DEFAULT;
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break;
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default:
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return -EINVAL;
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}
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args.namelen = strlen(args.name);
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if (acl) {
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args.valuelen = XFS_ACL_SIZE(acl->a_count);
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args.value = kmem_zalloc_large(args.valuelen, 0);
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if (!args.value)
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return -ENOMEM;
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xfs_acl_to_disk(args.value, acl);
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}
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error = xfs_attr_set(&args);
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kmem_free(args.value);
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/*
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* If the attribute didn't exist to start with that's fine.
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*/
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if (!acl && error == -ENOATTR)
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error = 0;
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if (!error)
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set_cached_acl(inode, type, acl);
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return error;
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}
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static int
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xfs_set_mode(struct inode *inode, umode_t mode)
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{
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int error = 0;
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if (mode != inode->i_mode) {
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struct iattr iattr;
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iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
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iattr.ia_mode = mode;
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iattr.ia_ctime = current_time(inode);
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error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
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}
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return error;
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}
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int
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xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
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{
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umode_t mode;
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bool set_mode = false;
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int error = 0;
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if (!acl)
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goto set_acl;
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error = -E2BIG;
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if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
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return error;
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if (type == ACL_TYPE_ACCESS) {
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error = posix_acl_update_mode(inode, &mode, &acl);
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if (error)
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return error;
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set_mode = true;
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}
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set_acl:
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error = __xfs_set_acl(inode, acl, type);
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if (error)
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return error;
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/*
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* We set the mode after successfully updating the ACL xattr because the
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* xattr update can fail at ENOSPC and we don't want to change the mode
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* if the ACL update hasn't been applied.
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*/
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if (set_mode)
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error = xfs_set_mode(inode, mode);
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return error;
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}
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/*
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* Invalidate any cached ACLs if the user has bypassed the ACL interface.
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* We don't validate the content whatsoever so it is caller responsibility to
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* provide data in valid format and ensure i_mode is consistent.
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*/
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void
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xfs_forget_acl(
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struct inode *inode,
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const char *name)
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{
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if (!strcmp(name, SGI_ACL_FILE))
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forget_cached_acl(inode, ACL_TYPE_ACCESS);
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else if (!strcmp(name, SGI_ACL_DEFAULT))
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forget_cached_acl(inode, ACL_TYPE_DEFAULT);
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}
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