Port of (bugfixed) 0.8.50 acl-ext2 to 2.5

This patch adds ACL support to the ext2 filesystem.

fs/Kconfig

@@ -970,6 +970,18 @@ config EXT2_FS_XATTR
 
 	  If unsure, say N.
 
+config EXT2_FS_POSIX_ACL
+	bool "Ext2 POSIX Access Control Lists"
+	depends on EXT2_FS_XATTR
+	---help---
+	  Posix Access Control Lists (ACLs) support permissions for users and
+	  groups beyond the owner/group/world scheme.
+
+	  To learn more about Access Control Lists, visit the Posix ACLs for
+	  Linux website <http://acl.bestbits.at/>.
+
+	  If you don't know what Access Control Lists are, say N
+
 config SYSV_FS
 	tristate "System V/Xenix/V7/Coherent file system support"
 	---help---

fs/ext2/Makefile

@@ -13,4 +13,8 @@ ifeq ($(CONFIG_EXT2_FS_XATTR),y)
 ext2-objs += xattr.o xattr_user.o
 endif
 
+ifeq ($(CONFIG_EXT2_FS_POSIX_ACL),y)
+ext2-objs += acl.o
+endif
+
 include $(TOPDIR)/Rules.make

fs/ext2/acl.h

+/*
+  File: fs/ext2/acl.h
+
+  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+*/
+
+#include <linux/xattr_acl.h>
+
+#define EXT2_ACL_VERSION	0x0001
+#define EXT2_ACL_MAX_ENTRIES	32
+
+typedef struct {
+	__u16		e_tag;
+	__u16		e_perm;
+	__u32		e_id;
+} ext2_acl_entry;
+
+typedef struct {
+	__u16		e_tag;
+	__u16		e_perm;
+} ext2_acl_entry_short;
+
+typedef struct {
+	__u32		a_version;
+} ext2_acl_header;
+
+static inline size_t ext2_acl_size(int count)
+{
+	if (count <= 4) {
+		return sizeof(ext2_acl_header) +
+		       count * sizeof(ext2_acl_entry_short);
+	} else {
+		return sizeof(ext2_acl_header) +
+		       4 * sizeof(ext2_acl_entry_short) +
+		       (count - 4) * sizeof(ext2_acl_entry);
+	}
+}
+
+static inline int ext2_acl_count(size_t size)
+{
+	ssize_t s;
+	size -= sizeof(ext2_acl_header);
+	s = size - 4 * sizeof(ext2_acl_entry_short);
+	if (s < 0) {
+		if (size % sizeof(ext2_acl_entry_short))
+			return -1;
+		return size / sizeof(ext2_acl_entry_short);
+	} else {
+		if (s % sizeof(ext2_acl_entry))
+			return -1;
+		return s / sizeof(ext2_acl_entry) + 4;
+	}
+}
+
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+
+/* Value for inode->u.ext2_i.i_acl and inode->u.ext2_i.i_default_acl
+   if the ACL has not been cached */
+#define EXT2_ACL_NOT_CACHED ((void *)-1)
+
+/* acl.c */
+extern int ext2_permission (struct inode *, int);
+extern int ext2_permission_locked (struct inode *, int);
+extern int ext2_acl_chmod (struct inode *);
+extern int ext2_init_acl (struct inode *, struct inode *);
+
+extern int init_ext2_acl(void);
+extern void exit_ext2_acl(void);
+
+#else
+#include <linux/sched.h>
+#define ext2_permission NULL
+#define ext2_get_acl	NULL
+#define ext2_set_acl	NULL
+
+static inline int
+ext2_acl_chmod (struct inode *inode)
+{
+	return 0;
+}
+
+static inline int ext2_init_acl (struct inode *inode, struct inode *dir)
+{
+	inode->i_mode &= ~current->fs->umask;
+	return 0;
+}
+#endif
+

fs/ext2/ext2.h

@@ -20,6 +20,10 @@ struct ext2_inode_info {
 	__u32	i_prealloc_block;
 	__u32	i_prealloc_count;
 	__u32	i_dir_start_lookup;
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+	struct posix_acl	*i_acl;
+	struct posix_acl	*i_default_acl;
+#endif
 	rwlock_t i_meta_lock;
 	struct inode	vfs_inode;
 };
@@ -85,6 +89,7 @@ extern void ext2_delete_inode (struct inode *);
 extern int ext2_sync_inode (struct inode *);
 extern void ext2_discard_prealloc (struct inode *);
 extern void ext2_truncate (struct inode *);
+extern int ext2_setattr (struct dentry *, struct iattr *);
 
 /* ioctl.c */
 extern int ext2_ioctl (struct inode *, struct file *, unsigned int,

fs/ext2/file.c

@@ -21,6 +21,7 @@
 #include <linux/time.h>
 #include "ext2.h"
 #include "xattr.h"
+#include "acl.h"
 
 /*
  * Called when an inode is released. Note that this is different
@@ -60,4 +61,6 @@ struct inode_operations ext2_file_inode_operations = {
 	.getxattr	= ext2_getxattr,
 	.listxattr	= ext2_listxattr,
 	.removexattr	= ext2_removexattr,
+	.setattr	= ext2_setattr,
+	.permission	= ext2_permission,
 };

fs/ext2/ialloc.c

@@ -19,6 +19,7 @@
 #include <linux/buffer_head.h>
 #include "ext2.h"
 #include "xattr.h"
+#include "acl.h"
 
 /*
  * ialloc.c contains the inodes allocation and deallocation routines
@@ -302,7 +303,6 @@ struct inode * ext2_new_inode(struct inode * dir, int mode)
 	struct ext2_super_block * es;
 	struct ext2_inode_info *ei;
 	int err;
-	struct inode *ret;
 
 	sb = dir->i_sb;
 	inode = new_inode(sb);
@@ -323,7 +323,6 @@ struct inode * ext2_new_inode(struct inode * dir, int mode)
 		goto fail;
 
 	err = -EIO;
-	brelse(bitmap_bh);
 	bitmap_bh = read_inode_bitmap(sb, group);
 	if (!bitmap_bh)
 		goto fail2;
@@ -339,6 +338,7 @@ struct inode * ext2_new_inode(struct inode * dir, int mode)
 		ll_rw_block(WRITE, 1, &bitmap_bh);
 		wait_on_buffer(bitmap_bh);
 	}
+	brelse(bitmap_bh);
 
 	ino = group * EXT2_INODES_PER_GROUP(sb) + i + 1;
 	if (ino < EXT2_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
@@ -395,21 +395,27 @@ struct inode * ext2_new_inode(struct inode * dir, int mode)
 		inode->i_flags |= S_DIRSYNC;
 	inode->i_generation = EXT2_SB(sb)->s_next_generation++;
 	insert_inode_hash(inode);
-	mark_inode_dirty(inode);
 
 	unlock_super(sb);
-	ret = inode;
 	if(DQUOT_ALLOC_INODE(inode)) {
 		DQUOT_DROP(inode);
-		inode->i_flags |= S_NOQUOTA;
-		inode->i_nlink = 0;
-		iput(inode);
-		ret = ERR_PTR(-EDQUOT);
-	} else {
-		ext2_debug("allocating inode %lu\n", inode->i_ino);
-		ext2_preread_inode(inode);
+		goto fail3;
 	}
-	goto out;
+	err = ext2_init_acl(inode, dir);
+	if (err) {
+		DQUOT_FREE_INODE(inode);
+		goto fail3;
+	}
+	mark_inode_dirty(inode);
+	ext2_debug("allocating inode %lu\n", inode->i_ino);
+	ext2_preread_inode(inode);
+	return inode;
+
+fail3:
+	inode->i_flags |= S_NOQUOTA;
+	inode->i_nlink = 0;
+	iput(inode);
+	return ERR_PTR(err);
 
 fail2:
 	desc = ext2_get_group_desc (sb, group, &bh2);
@@ -423,10 +429,10 @@ struct inode * ext2_new_inode(struct inode * dir, int mode)
 	unlock_super(sb);
 	make_bad_inode(inode);
 	iput(inode);
-	ret = ERR_PTR(err);
-	goto out;
+	return ERR_PTR(err);
 
 bad_count:
+	brelse(bitmap_bh);
 	ext2_error (sb, "ext2_new_inode",
 		    "Free inodes count corrupted in group %d",
 		    group);
@@ -439,9 +445,6 @@ struct inode * ext2_new_inode(struct inode * dir, int mode)
 	desc->bg_free_inodes_count = 0;
 	mark_buffer_dirty(bh2);
 	goto repeat;
-out:
-	brelse(bitmap_bh);
-	return ret;
 }
 
 unsigned long ext2_count_free_inodes (struct super_block * sb)

fs/ext2/inode.c

@@ -22,7 +22,6 @@
  *  Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
  */
 
-#include "ext2.h"
 #include <linux/smp_lock.h>
 #include <linux/time.h>
 #include <linux/highuid.h>
@@ -31,6 +30,8 @@
 #include <linux/module.h>
 #include <linux/buffer_head.h>
 #include <linux/mpage.h>
+#include "ext2.h"
+#include "acl.h"
 
 MODULE_AUTHOR("Remy Card and others");
 MODULE_DESCRIPTION("Second Extended Filesystem");
@@ -982,6 +983,10 @@ void ext2_read_inode (struct inode * inode)
 	struct ext2_inode * raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
 	int n;
 
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+	ei->i_acl = EXT2_ACL_NOT_CACHED;
+	ei->i_default_acl = EXT2_ACL_NOT_CACHED;
+#endif
 	if (IS_ERR(raw_inode))
  		goto bad_inode;
 
@@ -1177,3 +1182,18 @@ int ext2_sync_inode (struct inode *inode)
 {
 	return ext2_update_inode (inode, 1);
 }
+
+int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+	struct inode *inode = dentry->d_inode;
+	int error;
+
+	error = inode_change_ok(inode, iattr);
+	if (error)
+		return error;
+	inode_setattr(inode, iattr);
+	if (iattr->ia_valid & ATTR_MODE)
+		error = ext2_acl_chmod(inode);
+	return error;
+}
+

fs/ext2/namei.c

@@ -32,6 +32,7 @@
 #include <linux/pagemap.h>
 #include "ext2.h"
 #include "xattr.h"
+#include "acl.h"
 
 /*
  * Couple of helper functions - make the code slightly cleaner.
@@ -138,7 +139,10 @@ static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, int
 	struct inode * inode = ext2_new_inode (dir, mode);
 	int err = PTR_ERR(inode);
 	if (!IS_ERR(inode)) {
-		init_special_inode(inode, mode, rdev);
+		init_special_inode(inode, inode->i_mode, rdev);
+#ifdef CONFIG_EXT2_FS_EXT_ATTR
+		inode->i_op = &ext2_special_inode_operations;
+#endif
 		mark_inode_dirty(inode);
 		err = ext2_add_nondir(dentry, inode);
 	}
@@ -373,6 +377,8 @@ struct inode_operations ext2_dir_inode_operations = {
 	.getxattr	= ext2_getxattr,
 	.listxattr	= ext2_listxattr,
 	.removexattr	= ext2_removexattr,
+	.setattr	= ext2_setattr,
+	.permission	= ext2_permission,
 };
 
 struct inode_operations ext2_special_inode_operations = {
@@ -380,4 +386,6 @@ struct inode_operations ext2_special_inode_operations = {
 	.getxattr	= ext2_getxattr,
 	.listxattr	= ext2_listxattr,
 	.removexattr	= ext2_removexattr,
+	.setattr	= ext2_setattr,
+	.permission	= ext2_permission,
 };

fs/ext2/super.c

@@ -28,7 +28,7 @@
 #include <asm/uaccess.h>
 #include "ext2.h"
 #include "xattr.h"
-
+#include "acl.h"
 
 static void ext2_sync_super(struct super_block *sb,
 			    struct ext2_super_block *es);
@@ -155,6 +155,10 @@ static struct inode *ext2_alloc_inode(struct super_block *sb)
 	ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, SLAB_KERNEL);
 	if (!ei)
 		return NULL;
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+	ei->i_acl = EXT2_ACL_NOT_CACHED;
+	ei->i_default_acl = EXT2_ACL_NOT_CACHED;
+#endif
 	return &ei->vfs_inode;
 }
 
@@ -191,6 +195,26 @@ static void destroy_inodecache(void)
 		printk(KERN_INFO "ext2_inode_cache: not all structures were freed\n");
 }
 
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+
+static void ext2_clear_inode(struct inode *inode)
+{
+	struct ext2_inode_info *ei = EXT2_I(inode);
+
+	if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
+		posix_acl_release(ei->i_acl);
+		ei->i_acl = EXT2_ACL_NOT_CACHED;
+	}
+	if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
+		posix_acl_release(ei->i_default_acl);
+		ei->i_default_acl = EXT2_ACL_NOT_CACHED;
+	}
+}
+
+#else
+# define ext2_clear_inode NULL
+#endif
+
 static struct super_operations ext2_sops = {
 	.alloc_inode	= ext2_alloc_inode,
 	.destroy_inode	= ext2_destroy_inode,
@@ -202,6 +226,7 @@ static struct super_operations ext2_sops = {
 	.write_super	= ext2_write_super,
 	.statfs		= ext2_statfs,
 	.remount_fs	= ext2_remount,
+	.clear_inode	= ext2_clear_inode,
 };
 
 /* Yes, most of these are left as NULL!!
@@ -286,6 +311,13 @@ static int parse_options (char * options,
 		else if (!strcmp (this_char, "nouser_xattr"))
 			clear_opt (sbi->s_mount_opt, XATTR_USER);
 		else
+#endif
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+		if (!strcmp(this_char, "acl"))
+			set_opt(sbi->s_mount_opt, POSIX_ACL);
+		else if (!strcmp(this_char, "noacl"))
+			clear_opt(sbi->s_mount_opt, POSIX_ACL);
+		else
 #endif
 		if (!strcmp (this_char, "bsddf"))
 			clear_opt (sbi->s_mount_opt, MINIX_DF);
@@ -571,6 +603,8 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 		set_opt(sbi->s_mount_opt, NO_UID32);
 	if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 		set_opt(sbi->s_mount_opt, XATTR_USER);
+	if (def_mount_opts & EXT2_DEFM_ACL)
+		set_opt(sbi->s_mount_opt, POSIX_ACL);
 	
 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 		set_opt(sbi->s_mount_opt, ERRORS_PANIC);
@@ -583,6 +617,10 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 	if (!parse_options ((char *) data, sbi))
 		goto failed_mount;
 
+	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
+		((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
+		 MS_POSIXACL : 0);
+
 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 	    (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 	     EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
@@ -828,6 +866,9 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
 	if (!parse_options (data, sbi))
 		return -EINVAL;
 
+	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
+		((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
+
 	es = sbi->s_es;
 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 		return 0;

fs/ext2/xattr.c

@@ -60,6 +60,7 @@
 #include <asm/semaphore.h>
 #include "ext2.h"
 #include "xattr.h"
+#include "acl.h"
 
 /* These symbols may be needed by a module. */
 EXPORT_SYMBOL(ext2_xattr_register);
@@ -1100,19 +1101,35 @@ init_ext2_xattr(void)
 	err = ext2_xattr_register(EXT2_XATTR_INDEX_USER, &ext2_xattr_user_handler);
 	if (err)
 		return err;
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+	err = init_ext2_acl();
+	if (err)
+		goto out;
+#endif
 	ext2_xattr_cache = mb_cache_create("ext2_xattr", NULL,
 		sizeof(struct mb_cache_entry) +
 		sizeof(struct mb_cache_entry_index), 1, 6);
 	if (!ext2_xattr_cache) {
-		ext2_xattr_unregister(EXT2_XATTR_INDEX_USER, &ext2_xattr_user_handler);
-		return -ENOMEM;
+		err = -ENOMEM;
+		goto out1;
 	}
 	return 0;
+out1:
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+	exit_ext2_acl();
+out:
+#endif
+	ext2_xattr_unregister(EXT2_XATTR_INDEX_USER,
+			      &ext2_xattr_user_handler);
+	return err;
 }
 
 void
 exit_ext2_xattr(void)
 {
 	mb_cache_destroy(ext2_xattr_cache);
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+	exit_ext2_acl();
+#endif
 	ext2_xattr_unregister(EXT2_XATTR_INDEX_USER, &ext2_xattr_user_handler);
 }

include/linux/ext2_fs.h

@@ -308,6 +308,7 @@ struct ext2_inode {
 #define EXT2_MOUNT_MINIX_DF		0x0080	/* Mimics the Minix statfs */
 #define EXT2_MOUNT_NO_UID32		0x0200  /* Disable 32-bit UIDs */
 #define EXT2_MOUNT_XATTR_USER		0x4000	/* Extended user attributes */
+#define EXT2_MOUNT_POSIX_ACL		0x8000	/* POSIX Access Control Lists */
 
 #define clear_opt(o, opt)		o &= ~EXT2_MOUNT_##opt
 #define set_opt(o, opt)			o |= EXT2_MOUNT_##opt