Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759635Ab0GBSqr (ORCPT ); Fri, 2 Jul 2010 14:46:47 -0400 Received: from e23smtp09.au.ibm.com ([202.81.31.142]:50029 "EHLO e23smtp09.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759624Ab0GBSpB (ORCPT ); Fri, 2 Jul 2010 14:45:01 -0400 From: "Aneesh Kumar K.V" To: sfrench@us.ibm.com, ffilz@us.ibm.com, agruen@suse.de, adilger@sun.com, sandeen@redhat.com, tytso@mit.edu, staubach@redhat.com, bfields@citi.umich.edu, jlayton@redhat.com Cc: aneesh.kumar@linux.vnet.ibm.com, linux-fsdevel@vger.kernel.org, nfsv4@linux-nfs.org, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH -V2 11/16] richacl: Check if an acl is equivalent to a file mode Date: Sat, 3 Jul 2010 00:13:42 +0530 Message-Id: <1278096227-16784-12-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.2.rc1 In-Reply-To: <1278096227-16784-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1278096227-16784-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2937 Lines: 88 From: Andreas Gruenbacher This function is used to avoid storing richacls on disk if the acl can be computed from the file permission bits. Signed-off-by: Andreas Gruenbacher Signed-off-by: Aneesh Kumar K.V --- fs/richacl_base.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/richacl.h | 1 + 2 files changed, 49 insertions(+), 0 deletions(-) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index 804ef19..606f99e 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -524,3 +524,51 @@ richacl_inherit(const struct richacl *dir_acl, int isdir) return acl; } + +/** + * richacl_equiv_mode - check if @acl is equivalent to file permission bits + * @mode_p: the file mode (including the file type) + * + * If @acl can be fully represented by file permission bits, this function + * returns 0, and the file permission bits in @mode_p are set to the equivalent + * of @acl. + * + * This function is used to avoid storing richacls on disk if the acl can be + * computed from the file permission bits. It allows user-space to make sure + * that a file has no explicit richacl set. + */ +int +richacl_equiv_mode(const struct richacl *acl, mode_t *mode_p) +{ + const struct richace *ace = acl->a_entries; + unsigned int x; + mode_t mode; + + if (acl->a_count != 1 || + acl->a_flags || + !richace_is_everyone(ace) || + !richace_is_allow(ace) || + ace->e_flags & ~ACE4_SPECIAL_WHO) + return -1; + + /* + * Figure out the permissions we care about: ACE4_DELETE_CHILD is + * meaningless for non-directories, so we ignore it. + */ + x = ~ACE4_POSIX_ALWAYS_ALLOWED; + if (!S_ISDIR(*mode_p)) + x &= ~ACE4_DELETE_CHILD; + + if ((ace->e_mask & x) != (ACE4_POSIX_MODE_ALL & x)) + return -1; + + mode = richacl_masks_to_mode(acl); + if ((acl->a_owner_mask & x) != (richacl_mode_to_mask(mode >> 6) & x) || + (acl->a_group_mask & x) != (richacl_mode_to_mask(mode >> 3) & x) || + (acl->a_other_mask & x) != (richacl_mode_to_mask(mode) & x)) + return -1; + + *mode_p = (*mode_p & ~S_IRWXUGO) | mode; + return 0; +} +EXPORT_SYMBOL_GPL(richacl_equiv_mode); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index a1bf54a..b1a02e6 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -273,6 +273,7 @@ extern struct richacl *richacl_chmod(struct richacl *, mode_t); extern int richacl_permission(struct inode *, const struct richacl *, unsigned int); extern struct richacl *richacl_inherit(const struct richacl *, int); +extern int richacl_equiv_mode(const struct richacl *, mode_t *); /* richacl_inode.c */ -- 1.7.2.rc1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/