Port of (bugfixed) 0.8.50 acl-ext3 to 2.5.

This patch adds ACL support to the ext3 filesystem.

fs/Kconfig

@@ -300,6 +300,20 @@ config EXT3_FS_XATTR
 
 	  If unsure, say N.
 
+	  You need this for POSIX ACL support on ext3.
+
+config EXT3_FS_POSIX_ACL
+	bool "Ext3 POSIX Access Control Lists"
+	depends on EXT3_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_JBD could be its own option (even modular), but until there are
 # other users than ext3, we will simply make it be the same as CONFIG_EXT3_FS
 # dep_tristate '  Journal Block Device support (JBD for ext3)' CONFIG_JBD $CONFIG_EXT3_FS

fs/ext3/Makefile

@@ -13,4 +13,8 @@ ifeq ($(CONFIG_EXT3_FS_XATTR),y)
 ext3-objs += xattr.o xattr_user.o
 endif
 
+ifeq ($(CONFIG_EXT3_FS_POSIX_ACL),y)
+ext3-objs += acl.o
+endif
+
 include $(TOPDIR)/Rules.make

fs/ext3/acl.h

+/*
+  File: fs/ext3/acl.h
+
+  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+*/
+
+#include <linux/xattr_acl.h>
+
+#define EXT3_ACL_VERSION	0x0001
+#define EXT3_ACL_MAX_ENTRIES	32
+
+typedef struct {
+	__u16		e_tag;
+	__u16		e_perm;
+	__u32		e_id;
+} ext3_acl_entry;
+
+typedef struct {
+	__u16		e_tag;
+	__u16		e_perm;
+} ext3_acl_entry_short;
+
+typedef struct {
+	__u32		a_version;
+} ext3_acl_header;
+
+static inline size_t ext3_acl_size(int count)
+{
+	if (count <= 4) {
+		return sizeof(ext3_acl_header) +
+		       count * sizeof(ext3_acl_entry_short);
+	} else {
+		return sizeof(ext3_acl_header) +
+		       4 * sizeof(ext3_acl_entry_short) +
+		       (count - 4) * sizeof(ext3_acl_entry);
+	}
+}
+
+static inline int ext3_acl_count(size_t size)
+{
+	ssize_t s;
+	size -= sizeof(ext3_acl_header);
+	s = size - 4 * sizeof(ext3_acl_entry_short);
+	if (s < 0) {
+		if (size % sizeof(ext3_acl_entry_short))
+			return -1;
+		return size / sizeof(ext3_acl_entry_short);
+	} else {
+		if (s % sizeof(ext3_acl_entry))
+			return -1;
+		return s / sizeof(ext3_acl_entry) + 4;
+	}
+}
+
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+
+/* Value for inode->u.ext3_i.i_acl and inode->u.ext3_i.i_default_acl
+   if the ACL has not been cached */
+#define EXT3_ACL_NOT_CACHED ((void *)-1)
+
+/* acl.c */
+extern int ext3_permission (struct inode *, int);
+extern int ext3_permission_locked (struct inode *, int);
+extern int ext3_acl_chmod (struct inode *);
+extern int ext3_init_acl (handle_t *, struct inode *, struct inode *);
+
+extern int init_ext3_acl(void);
+extern void exit_ext3_acl(void);
+
+#else  /* CONFIG_EXT3_FS_POSIX_ACL */
+#include <linux/sched.h>
+#define ext3_permission NULL
+
+static inline int
+ext3_acl_chmod(struct inode *inode)
+{
+	return 0;
+}
+
+static inline int
+ext3_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+	inode->i_mode &= ~current->fs->umask;
+	return 0;
+}
+#endif  /* CONFIG_EXT3_FS_POSIX_ACL */
+

fs/ext3/file.c

@@ -24,6 +24,7 @@
 #include <linux/ext3_fs.h>
 #include <linux/ext3_jbd.h>
 #include "xattr.h"
+#include "acl.h"
 
 /*
  * Called when an inode is released. Note that this is different
@@ -102,5 +103,6 @@ struct inode_operations ext3_file_inode_operations = {
 	.getxattr	= ext3_getxattr,
 	.listxattr	= ext3_listxattr,
 	.removexattr	= ext3_removexattr,
+	.permission	= ext3_permission,
 };
 

fs/ext3/ialloc.c

@@ -26,6 +26,7 @@
 #include <asm/byteorder.h>
 
 #include "xattr.h"
+#include "acl.h"
 
 /*
  * ialloc.c contains the inodes allocation and deallocation routines
@@ -423,20 +424,27 @@ struct inode *ext3_new_inode(handle_t *handle, struct inode * dir, int mode)
 	inode->i_generation = EXT3_SB(sb)->s_next_generation++;
 
 	ei->i_state = EXT3_STATE_NEW;
-	err = ext3_mark_inode_dirty(handle, inode);
-	if (err) goto fail;
-	
+
 	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 {
-		ext3_debug("allocating inode %lu\n", inode->i_ino);
+		err = -EDQUOT;
+		goto fail2;
 	}
+	err = ext3_init_acl(handle, inode, dir);
+	if (err) {
+		DQUOT_FREE_INODE(inode);
+		goto fail2;
+  	}
+	err = ext3_mark_inode_dirty(handle, inode);
+	if (err) {
+		ext3_std_error(sb, err);
+		DQUOT_FREE_INODE(inode);
+		goto fail2;
+	}
+
+	ext3_debug("allocating inode %lu\n", inode->i_ino);
 	goto really_out;
 fail:
 	ext3_std_error(sb, err);
@@ -447,6 +455,12 @@ struct inode *ext3_new_inode(handle_t *handle, struct inode * dir, int mode)
 really_out:
 	brelse(bitmap_bh);
 	return ret;
+
+fail2:
+	inode->i_flags |= S_NOQUOTA;
+	inode->i_nlink = 0;
+	iput(inode);
+	return ERR_PTR(err);
 }
 
 /* Verify that we are loading a valid orphan from disk */

fs/ext3/inode.c

@@ -34,6 +34,8 @@
 #include <linux/string.h>
 #include <linux/buffer_head.h>
 #include <linux/mpage.h>
+#include "xattr.h"
+#include "acl.h"
 
 /*
  * SEARCH_FROM_ZERO forces each block allocation to search from the start
@@ -2199,7 +2201,11 @@ void ext3_read_inode(struct inode * inode)
 	struct buffer_head *bh;
 	int block;
 	
-	if(ext3_get_inode_loc(inode, &iloc))
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+	ei->i_acl = EXT3_ACL_NOT_CACHED;
+	ei->i_default_acl = EXT3_ACL_NOT_CACHED;
+#endif
+	if (ext3_get_inode_loc(inode, &iloc))
 		goto bad_inode;
 	bh = iloc.bh;
 	raw_inode = iloc.raw_inode;
@@ -2491,13 +2497,8 @@ void ext3_write_inode(struct inode *inode, int wait)
  * be freed, so we have a strong guarantee that no future commit will
  * leave these blocks visible to the user.)  
  *
- * This is only needed for regular files.  rmdir() has its own path, and
- * we can never truncate a direcory except on final unlink (at which
- * point i_nlink is zero so recovery is easy.)
- *
- * Called with the BKL.  
+ * Called with inode->sem down.
  */
-
 int ext3_setattr(struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = dentry->d_inode;
@@ -2517,7 +2518,8 @@ int ext3_setattr(struct dentry *dentry, struct iattr *attr)
 
 	lock_kernel();
 
-	if (attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
+	if (S_ISREG(inode->i_mode) &&
+	    attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
 		handle_t *handle;
 
 		handle = ext3_journal_start(inode, 3);
@@ -2542,6 +2544,9 @@ int ext3_setattr(struct dentry *dentry, struct iattr *attr)
 	if (inode->i_nlink)
 		ext3_orphan_del(NULL, inode);
 
+	if (!rc && (ia_valid & ATTR_MODE))
+		rc = ext3_acl_chmod(inode);
+
 err_out:
 	ext3_std_error(inode->i_sb, error);
 	unlock_kernel();

fs/ext3/namei.c

@@ -37,7 +37,7 @@
 #include <linux/buffer_head.h>
 #include <linux/smp_lock.h>
 #include "xattr.h"
-
+#include "acl.h"
 
 /*
  * define how far ahead to read directories while searching them.
@@ -1624,7 +1624,10 @@ static int ext3_mknod (struct inode * dir, struct dentry *dentry,
 	inode = ext3_new_inode (handle, dir, mode);
 	err = PTR_ERR(inode);
 	if (!IS_ERR(inode)) {
-		init_special_inode(inode, mode, rdev);
+		init_special_inode(inode, inode->i_mode, rdev);
+#ifdef CONFIG_EXT3_FS_XATTR
+		inode->i_op = &ext3_special_inode_operations;
+#endif
 		err = ext3_add_nondir(handle, dentry, inode);
 		ext3_mark_inode_dirty(handle, inode);
 	}
@@ -2281,17 +2284,21 @@ struct inode_operations ext3_dir_inode_operations = {
 	.rmdir		= ext3_rmdir,
 	.mknod		= ext3_mknod,
 	.rename		= ext3_rename,
+	.setattr	= ext3_setattr,
 	.setxattr	= ext3_setxattr,	
 	.getxattr	= ext3_getxattr,	
 	.listxattr	= ext3_listxattr,	
 	.removexattr	= ext3_removexattr,
+	.permission	= ext3_permission,
 };
 
 struct inode_operations ext3_special_inode_operations = {
+	.setattr	= ext3_setattr,
 	.setxattr	= ext3_setxattr,
 	.getxattr	= ext3_getxattr,
 	.listxattr	= ext3_listxattr,
 	.removexattr	= ext3_removexattr,
+	.permission	= ext3_permission,
 };
 
  

fs/ext3/super.c

@@ -31,6 +31,7 @@
 #include <linux/buffer_head.h>
 #include <asm/uaccess.h>
 #include "xattr.h"
+#include "acl.h"
 
 #ifdef CONFIG_JBD_DEBUG
 static int ext3_ro_after; /* Make fs read-only after this many jiffies */
@@ -428,6 +429,10 @@ static struct inode *ext3_alloc_inode(struct super_block *sb)
 	ei = kmem_cache_alloc(ext3_inode_cachep, SLAB_NOFS);
 	if (!ei)
 		return NULL;
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+	ei->i_acl = EXT3_ACL_NOT_CACHED;
+	ei->i_default_acl = EXT3_ACL_NOT_CACHED;
+#endif
 	return &ei->vfs_inode;
 }
 
@@ -465,6 +470,26 @@ static void destroy_inodecache(void)
 		printk(KERN_INFO "ext3_inode_cache: not all structures were freed\n");
 }
 
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+
+static void ext3_clear_inode(struct inode *inode)
+{
+       if (EXT3_I(inode)->i_acl &&
+           EXT3_I(inode)->i_acl != EXT3_ACL_NOT_CACHED) {
+               posix_acl_release(EXT3_I(inode)->i_acl);
+               EXT3_I(inode)->i_acl = EXT3_ACL_NOT_CACHED;
+       }
+       if (EXT3_I(inode)->i_default_acl &&
+           EXT3_I(inode)->i_default_acl != EXT3_ACL_NOT_CACHED) {
+               posix_acl_release(EXT3_I(inode)->i_default_acl);
+               EXT3_I(inode)->i_default_acl = EXT3_ACL_NOT_CACHED;
+       }
+}
+
+#else
+# define ext3_clear_inode NULL
+#endif
+
 static struct super_operations ext3_sops = {
 	.alloc_inode	= ext3_alloc_inode,
 	.destroy_inode	= ext3_destroy_inode,
@@ -479,6 +504,7 @@ static struct super_operations ext3_sops = {
 	.unlockfs	= ext3_unlockfs,		/* BKL not held.  We take it */
 	.statfs		= ext3_statfs,		/* BKL not held. */
 	.remount_fs	= ext3_remount,		/* BKL held */
+	.clear_inode	= ext3_clear_inode,	/* BKL not needed. */
 };
 
 struct dentry *ext3_get_parent(struct dentry *child);
@@ -559,6 +585,13 @@ static int parse_options (char * options, struct ext3_sb_info *sbi,
 		else if (!strcmp (this_char, "nouser_xattr"))
 			clear_opt (sbi->s_mount_opt, XATTR_USER);
 		else
+#endif
+#ifdef CONFIG_EXT3_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);
@@ -1028,6 +1061,8 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
 		set_opt(sbi->s_mount_opt, NO_UID32);
 	if (def_mount_opts & EXT3_DEFM_XATTR_USER)
 		set_opt(sbi->s_mount_opt, XATTR_USER);
+	if (def_mount_opts & EXT3_DEFM_ACL)
+		set_opt(sbi->s_mount_opt, POSIX_ACL);
 	if ((def_mount_opts & EXT3_DEFM_JMODE) == EXT3_DEFM_JMODE_DATA)
 		sbi->s_mount_opt |= EXT3_MOUNT_JOURNAL_DATA;
 	else if ((def_mount_opts & EXT3_DEFM_JMODE) == EXT3_DEFM_JMODE_ORDERED)
@@ -1046,6 +1081,9 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
 	if (!parse_options ((char *) data, sbi, &journal_inum, 0))
 		goto failed_mount;
 
+	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
+		((sbi->s_mount_opt & EXT3_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
+
 	if (le32_to_cpu(es->s_rev_level) == EXT3_GOOD_OLD_REV &&
 	    (EXT3_HAS_COMPAT_FEATURE(sb, ~0U) ||
 	     EXT3_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
@@ -1735,6 +1773,9 @@ int ext3_remount (struct super_block * sb, int * flags, char * data)
 	if (sbi->s_mount_opt & EXT3_MOUNT_ABORT)
 		ext3_abort(sb, __FUNCTION__, "Abort forced by user");
 
+	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
+		((sbi->s_mount_opt & EXT3_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
+
 	es = sbi->s_es;
 
 	ext3_init_journal_params(sbi, sbi->s_journal);

fs/ext3/xattr.c

@@ -61,6 +61,7 @@
 #include <linux/quotaops.h>
 #include <asm/semaphore.h>
 #include "xattr.h"
+#include "acl.h"
 
 #define EXT3_EA_USER "user."
 
@@ -1105,15 +1106,27 @@ init_ext3_xattr(void)
 	err = ext3_xattr_register(EXT3_XATTR_INDEX_USER, &ext3_xattr_user_handler);
 	if (err)
 		return err;
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+	err = init_ext3_acl();
+	if (err)
+		goto out;
+#endif
 	ext3_xattr_cache = mb_cache_create("ext3_xattr", NULL,
 		sizeof(struct mb_cache_entry) +
 		sizeof(struct mb_cache_entry_index), 1, 6);
 	if (!ext3_xattr_cache) {
-		ext3_xattr_unregister(EXT3_XATTR_INDEX_USER, &ext3_xattr_user_handler);
-		return -ENOMEM;
+		err = -ENOMEM;
+		goto out1;
 	}
-
 	return 0;
+out1:
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+	exit_ext3_acl();
+out:
+#endif
+	ext3_xattr_unregister(EXT3_XATTR_INDEX_USER,
+			      &ext3_xattr_user_handler);
+	return err;
 }
 
 void
@@ -1122,6 +1135,8 @@ exit_ext3_xattr(void)
 	if (ext3_xattr_cache)
 		mb_cache_destroy(ext3_xattr_cache);
 	ext3_xattr_cache = NULL;
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+	exit_ext3_acl();
+#endif
 	ext3_xattr_unregister(EXT3_XATTR_INDEX_USER, &ext3_xattr_user_handler);
 }
-

include/linux/ext3_fs.h

@@ -323,6 +323,7 @@ struct ext3_inode {
 #define EXT3_MOUNT_UPDATE_JOURNAL	0x1000	/* Update the journal format */
 #define EXT3_MOUNT_NO_UID32		0x2000  /* Disable 32-bit UIDs */
 #define EXT3_MOUNT_XATTR_USER		0x4000	/* Extended user attributes */
+#define EXT3_MOUNT_POSIX_ACL		0x8000	/* POSIX Access Control Lists */
 
 /* Compatibility, for having both ext2_fs.h and ext3_fs.h included at once */
 #ifndef _LINUX_EXT2_FS_H

include/linux/ext3_fs_i.h

@@ -41,6 +41,10 @@ struct ext3_inode_info {
 	__u32	i_prealloc_count;
 #endif
 	__u32	i_dir_start_lookup;
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+	struct posix_acl	*i_acl;
+	struct posix_acl	*i_default_acl;
+#endif
 	
 	struct list_head i_orphan;	/* unlinked but open inodes */