X-Git-Url: https://git.carlh.net/gitweb/?a=blobdiff_plain;f=lwext4%2Fext4_xattr.c;h=14baed8165ae358a927a87f884e287baf1c50037;hb=fe2cde8c8128fff855522a84a8f2864e6ed69686;hp=521866b1f54e53d30b4dbb3926514e634420867b;hpb=753d3b470be3150f50d99fea84280424ae5c3eb2;p=lwext4.git

diff --git a/lwext4/ext4_xattr.c b/lwext4/ext4_xattr.c
index 521866b..14baed8 100644
--- a/lwext4/ext4_xattr.c
+++ b/lwext4/ext4_xattr.c
@@ -1,22 +1,174 @@
+/*
+ * Copyright (c) 2015 Grzegorz Kostka (kostka.grzegorz@gmail.com)
+ * Copyright (c) 2015 Kaho Ng (ngkaho1234@gmail.com)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** @addtogroup lwext4
+ * @{
+ */
+/**
+ * @file  ext4_xattr.c
+ * @brief Extended Attribute manipulation.
+ */
+
 #include "ext4_config.h"
 #include "ext4_types.h"
 #include "ext4_fs.h"
 #include "ext4_errno.h"
 #include "ext4_blockdev.h"
 #include "ext4_super.h"
+#include "ext4_crc32.h"
 #include "ext4_debug.h"
 #include "ext4_block_group.h"
 #include "ext4_balloc.h"
 #include "ext4_inode.h"
-#include "ext4_extent.h"
 
 #include <string.h>
 #include <stdlib.h>
 
+/**
+ * @file  ext4_xattr.c
+ * @brief Extended Attribute Manipulation
+ */
+
+#define NAME_HASH_SHIFT 5
+#define VALUE_HASH_SHIFT 16
+
+static inline void ext4_xattr_compute_hash(struct ext4_xattr_header *header,
+					   struct ext4_xattr_entry *entry)
+{
+	uint32_t hash = 0;
+	char *name = EXT4_XATTR_NAME(entry);
+	int n;
+
+	for (n = 0; n < entry->e_name_len; n++) {
+		hash = (hash << NAME_HASH_SHIFT) ^
+		       (hash >> (8 * sizeof(hash) - NAME_HASH_SHIFT)) ^ *name++;
+	}
+
+	if (entry->e_value_block == 0 && entry->e_value_size != 0) {
+		uint32_t *value =
+		    (uint32_t *)((char *)header + to_le16(entry->e_value_offs));
+		for (n = (to_le32(entry->e_value_size) + EXT4_XATTR_ROUND) >>
+			 EXT4_XATTR_PAD_BITS;
+		     n; n--) {
+			hash = (hash << VALUE_HASH_SHIFT) ^
+			       (hash >> (8 * sizeof(hash) - VALUE_HASH_SHIFT)) ^
+			       to_le32(*value++);
+		}
+	}
+	entry->e_hash = to_le32(hash);
+}
+
+#define BLOCK_HASH_SHIFT 16
+
+/*
+ * ext4_xattr_rehash()
+ *
+ * Re-compute the extended attribute hash value after an entry has changed.
+ */
+static void ext4_xattr_rehash(struct ext4_xattr_header *header,
+			      struct ext4_xattr_entry *entry)
+{
+	struct ext4_xattr_entry *here;
+	uint32_t hash = 0;
+
+	ext4_xattr_compute_hash(header, entry);
+	here = EXT4_XATTR_ENTRY(header + 1);
+	while (!EXT4_XATTR_IS_LAST_ENTRY(here)) {
+		if (!here->e_hash) {
+			/* Block is not shared if an entry's hash value == 0 */
+			hash = 0;
+			break;
+		}
+		hash = (hash << BLOCK_HASH_SHIFT) ^
+		       (hash >> (8 * sizeof(hash) - BLOCK_HASH_SHIFT)) ^
+		       to_le32(here->e_hash);
+		here = EXT4_XATTR_NEXT(here);
+	}
+	header->h_hash = to_le32(hash);
+}
+
+#if CONFIG_META_CSUM_ENABLE
+static uint32_t
+ext4_xattr_block_checksum(struct ext4_inode_ref *inode_ref,
+			  ext4_fsblk_t blocknr,
+			  struct ext4_xattr_header *header)
+{
+	uint32_t checksum = 0;
+	uint64_t le64_blocknr = blocknr;
+	struct ext4_sblock *sb = &inode_ref->fs->sb;
+
+	if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
+		uint32_t orig_checksum;
+
+		/* Preparation: temporarily set bg checksum to 0 */
+		orig_checksum = header->h_checksum;
+		header->h_checksum = 0;
+		/* First calculate crc32 checksum against fs uuid */
+		checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
+				sizeof(sb->uuid));
+		/* Then calculate crc32 checksum block number */
+		checksum = ext4_crc32c(checksum, &le64_blocknr,
+				     sizeof(le64_blocknr));
+		/* Finally calculate crc32 checksum against 
+		 * the entire xattr block */
+		checksum = ext4_crc32c(checksum, header,
+				   ext4_sb_get_block_size(sb));
+		header->h_checksum = orig_checksum;
+	}
+	return checksum;
+}
+#else
+#define ext4_xattr_block_checksum(...) 0
+#endif
+
+static void
+ext4_xattr_set_block_checksum(struct ext4_inode_ref *inode_ref,
+			      ext4_fsblk_t blocknr __unused,
+			      struct ext4_xattr_header *header)
+{
+	struct ext4_sblock *sb = &inode_ref->fs->sb;
+	if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
+		return;
+
+	header->h_checksum =
+		ext4_xattr_block_checksum(inode_ref, blocknr, header);
+}
+
 static int ext4_xattr_item_cmp(struct ext4_xattr_item *a,
-				struct ext4_xattr_item *b)
+			       struct ext4_xattr_item *b)
 {
 	int result;
+	if (a->in_inode && !b->in_inode)
+		return -1;
+	
+	if (!a->in_inode && b->in_inode)
+		return 1;
+
 	result = a->name_index - b->name_index;
 	if (result)
 		return result;
@@ -28,38 +180,38 @@ static int ext4_xattr_item_cmp(struct ext4_xattr_item *a,
 	return memcmp(a->name, b->name, a->name_len);
 }
 
-RB_GENERATE (ext4_xattr_tree,
-	     ext4_xattr_item,
-	     node,
-	     ext4_xattr_item_cmp)
+RB_GENERATE_INTERNAL(ext4_xattr_tree, ext4_xattr_item, node,
+		     ext4_xattr_item_cmp, static inline)
 
 static struct ext4_xattr_item *
-ext4_xattr_item_alloc(uint8_t name_index,
-		      char   *name,
-		      size_t  name_len)
+ext4_xattr_item_alloc(uint8_t name_index, const char *name, size_t name_len)
 {
 	struct ext4_xattr_item *item;
-	item = malloc(sizeof(struct ext4_xattr_item) +
-			name_len);
+	item = malloc(sizeof(struct ext4_xattr_item) + name_len);
 	if (!item)
 		return NULL;
 
 	item->name_index = name_index;
-	item->name       = (char *)(item + 1);
-	item->name_len   = name_len;
-	item->data       = NULL;
-	item->data_size  = 0;
-	
+	item->name = (char *)(item + 1);
+	item->name_len = name_len;
+	item->data = NULL;
+	item->data_size = 0;
+
 	memset(&item->node, 0, sizeof(item->node));
 	memcpy(item->name, name, name_len);
 
+	if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
+	    name_len == 4 &&
+	    !memcmp(name, "data", 4))
+		item->in_inode = true;
+	else
+		item->in_inode = false;
+
 	return item;
 }
 
-static int
-ext4_xattr_item_alloc_data(struct ext4_xattr_item *item,
-			   void *orig_data,
-			   size_t data_size)
+static int ext4_xattr_item_alloc_data(struct ext4_xattr_item *item,
+				      const void *orig_data, size_t data_size)
 {
 	void *data = NULL;
 	ext4_assert(!item->data);
@@ -75,8 +227,7 @@ ext4_xattr_item_alloc_data(struct ext4_xattr_item *item,
 	return EOK;
 }
 
-static void
-ext4_xattr_item_free_data(struct ext4_xattr_item *item)
+static void ext4_xattr_item_free_data(struct ext4_xattr_item *item)
 {
 	ext4_assert(item->data);
 	free(item->data);
@@ -84,9 +235,8 @@ ext4_xattr_item_free_data(struct ext4_xattr_item *item)
 	item->data_size = 0;
 }
 
-static int
-ext4_xattr_item_resize_data(struct ext4_xattr_item *item,
-			    size_t new_data_size)
+static int ext4_xattr_item_resize_data(struct ext4_xattr_item *item,
+				       size_t new_data_size)
 {
 	if (new_data_size != item->data_size) {
 		void *new_data;
@@ -100,8 +250,7 @@ ext4_xattr_item_resize_data(struct ext4_xattr_item *item,
 	return EOK;
 }
 
-static void
-ext4_xattr_item_free(struct ext4_xattr_item *item)
+static void ext4_xattr_item_free(struct ext4_xattr_item *item)
 {
 	if (item->data)
 		ext4_xattr_item_free_data(item);
@@ -109,36 +258,32 @@ ext4_xattr_item_free(struct ext4_xattr_item *item)
 	free(item);
 }
 
-
 static void *ext4_xattr_entry_data(struct ext4_xattr_ref *xattr_ref,
 				   struct ext4_xattr_entry *entry,
 				   bool in_inode)
 {
-	void *ret;
+	char *ret;
 	if (in_inode) {
 		struct ext4_xattr_ibody_header *header;
 		struct ext4_xattr_entry *first_entry;
-		uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb,
-						 inode_size);
+		int16_t inode_size =
+		    ext4_get16(&xattr_ref->fs->sb, inode_size);
 		header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 		first_entry = EXT4_XATTR_IFIRST(header);
- 
-		ret = (void *)((char *)first_entry + to_le16(entry->e_value_offs));
-		if ((char *)ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size))
-			- (char *)xattr_ref->inode_ref->inode >
-		    inode_size)
-			ret = NULL;
 
-	} else {
-		uint32_t block_size =
-				ext4_sb_get_block_size(&xattr_ref->fs->sb);
-		ret = (void *)((char *)xattr_ref->block.data + 
-				to_le16(entry->e_value_offs));
-		if ((char *)ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size))
-			- (char *)xattr_ref->block.data >
-		    block_size)
+		ret = ((char *)first_entry + to_le16(entry->e_value_offs));
+		if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
+			(char *)xattr_ref->inode_ref->inode > inode_size)
 			ret = NULL;
+
+		return ret;
+
 	}
+	int32_t block_size = ext4_sb_get_block_size(&xattr_ref->fs->sb);
+	ret = ((char *)xattr_ref->block.data + to_le16(entry->e_value_offs));
+	if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
+			(char *)xattr_ref->block.data > block_size)
+		ret = NULL;
 	return ret;
 }
 
@@ -153,36 +298,33 @@ static int ext4_xattr_block_fetch(struct ext4_xattr_ref *xattr_ref)
 	entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 
 	size_rem = ext4_sb_get_block_size(&xattr_ref->fs->sb);
-	for(;size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
-	    entry = EXT4_XATTR_NEXT(entry),
-	    size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
+	for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
+	     entry = EXT4_XATTR_NEXT(entry),
+	     size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 		struct ext4_xattr_item *item;
-		char *e_name = (char *)(entry + 1);
+		char *e_name = EXT4_XATTR_NAME(entry);
 
-		data = ext4_xattr_entry_data(xattr_ref, entry,
-					     false);
+		data = ext4_xattr_entry_data(xattr_ref, entry, false);
 		if (!data) {
 			ret = EIO;
 			goto Finish;
 		}
 
-		item = ext4_xattr_item_alloc(entry->e_name_index,
-					     e_name,
+		item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 					     (size_t)entry->e_name_len);
 		if (!item) {
 			ret = ENOMEM;
 			goto Finish;
 		}
-		if (ext4_xattr_item_alloc_data(item,
-					       data,
-					       to_le32(entry->e_value_size))
-			!= EOK) {
+		if (ext4_xattr_item_alloc_data(
+			item, data, to_le32(entry->e_value_size)) != EOK) {
 			ext4_xattr_item_free(item);
 			ret = ENOMEM;
 			goto Finish;
 		}
 		RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
-
+		xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
+				      EXT4_XATTR_LEN(item->name_len);
 	}
 
 Finish:
@@ -196,60 +338,67 @@ static int ext4_xattr_inode_fetch(struct ext4_xattr_ref *xattr_ref)
 	int ret = EOK;
 	struct ext4_xattr_ibody_header *header = NULL;
 	struct ext4_xattr_entry *entry = NULL;
-	uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb,
-					 inode_size);
+	uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 
 	header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 	entry = EXT4_XATTR_IFIRST(header);
 
-	size_rem = inode_size -
-		EXT4_GOOD_OLD_INODE_SIZE -
-		xattr_ref->inode_ref->inode->extra_isize;
-	for(;size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
-	    entry = EXT4_XATTR_NEXT(entry),
-	    size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
+	size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
+		   xattr_ref->inode_ref->inode->extra_isize;
+	for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
+	     entry = EXT4_XATTR_NEXT(entry),
+	     size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 		struct ext4_xattr_item *item;
-		char *e_name = (char *)(entry + 1);
+		char *e_name = EXT4_XATTR_NAME(entry);
 
-		data = ext4_xattr_entry_data(xattr_ref, entry,
-					     true);
+		data = ext4_xattr_entry_data(xattr_ref, entry, true);
 		if (!data) {
 			ret = EIO;
 			goto Finish;
 		}
 
-		item = ext4_xattr_item_alloc(entry->e_name_index,
-					     e_name,
+		item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 					     (size_t)entry->e_name_len);
 		if (!item) {
 			ret = ENOMEM;
 			goto Finish;
 		}
-		if (ext4_xattr_item_alloc_data(item,
-					       data,
-					       to_le32(entry->e_value_size))
-			!= EOK) {
+		if (ext4_xattr_item_alloc_data(
+			item, data, to_le32(entry->e_value_size)) != EOK) {
 			ext4_xattr_item_free(item);
 			ret = ENOMEM;
 			goto Finish;
 		}
 		RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
+		xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
+				      EXT4_XATTR_LEN(item->name_len);
 	}
 
 Finish:
 	return ret;
 }
 
+static size_t ext4_xattr_inode_space(struct ext4_xattr_ref *xattr_ref)
+{
+	uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
+	uint16_t size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
+			    xattr_ref->inode_ref->inode->extra_isize;
+	return size_rem;
+}
+
+static size_t ext4_xattr_block_space(struct ext4_xattr_ref *xattr_ref)
+{
+	return ext4_sb_get_block_size(&xattr_ref->fs->sb);
+}
+
 static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
 {
 	int ret = EOK;
-	uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb,
-					 inode_size);
+	uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 	if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
 		ret = ext4_xattr_inode_fetch(xattr_ref);
 		if (ret != EOK)
 			return ret;
-
 	}
 
 	if (xattr_ref->block_loaded)
@@ -259,35 +408,439 @@ static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
 	return ret;
 }
 
-static void
-ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
+static struct ext4_xattr_item *
+ext4_xattr_lookup_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
+		       const char *name, size_t name_len)
+{
+	struct ext4_xattr_item tmp = {
+		.name_index = name_index,
+		.name = (char *)name, /*RB_FIND - won't touch this string*/
+		.name_len = name_len,
+	};
+	if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
+	    name_len == 4 &&
+	    !memcmp(name, "data", 4))
+		tmp.in_inode = true;
+
+	return RB_FIND(ext4_xattr_tree, &xattr_ref->root, &tmp);
+}
+
+static struct ext4_xattr_item *
+ext4_xattr_insert_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
+		       const char *name, size_t name_len, const void *data,
+		       size_t data_size)
+{
+	struct ext4_xattr_item *item;
+	item = ext4_xattr_item_alloc(name_index, name, name_len);
+	if (!item)
+		return NULL;
+
+	if ((xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
+		EXT4_XATTR_LEN(item->name_len)
+			>
+	    ext4_xattr_inode_space(xattr_ref) -
+	    	sizeof(struct ext4_xattr_ibody_header))
+		&&
+	    (xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
+		EXT4_XATTR_LEN(item->name_len) >
+	    ext4_xattr_block_space(xattr_ref) -
+	    	sizeof(struct ext4_xattr_header))) {
+		ext4_xattr_item_free(item);
+
+		return NULL;
+	}
+	if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {
+		ext4_xattr_item_free(item);
+		return NULL;
+	}
+	RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
+	xattr_ref->ea_size +=
+	    EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
+	xattr_ref->dirty = true;
+	return item;
+}
+
+static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
+				  uint8_t name_index, const char *name,
+				  size_t name_len)
+{
+	int ret = ENOENT;
+	struct ext4_xattr_item *item =
+	    ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
+	if (item) {
+		if (item == xattr_ref->iter_from)
+			xattr_ref->iter_from =
+			    RB_NEXT(ext4_xattr_tree, &xattr_ref->root, item);
+
+		xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
+				      EXT4_XATTR_LEN(item->name_len);
+
+		RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
+		ext4_xattr_item_free(item);
+		xattr_ref->dirty = true;
+		ret = EOK;
+	}
+	return ret;
+}
+
+static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
+				  struct ext4_xattr_item *item,
+				  size_t new_data_size)
+{
+	int ret = EOK;
+	size_t old_data_size = item->data_size;
+	if ((xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
+		EXT4_XATTR_SIZE(new_data_size)
+			>
+	    ext4_xattr_inode_space(xattr_ref) -
+	    	sizeof(struct ext4_xattr_ibody_header))
+		&&
+	    (xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
+		EXT4_XATTR_SIZE(new_data_size)
+			>
+	    ext4_xattr_block_space(xattr_ref) -
+	    	sizeof(struct ext4_xattr_header))) {
+
+		return ENOSPC;
+	}
+	ret = ext4_xattr_item_resize_data(item, new_data_size);
+	if (ret != EOK) {
+		return ret;
+	}
+	xattr_ref->ea_size =
+	    xattr_ref->ea_size -
+	    EXT4_XATTR_SIZE(old_data_size) +
+	    EXT4_XATTR_SIZE(new_data_size);
+	xattr_ref->dirty = true;
+	return ret;
+}
+
+static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 {
 	struct ext4_xattr_item *item, *save_item;
-	RB_FOREACH_SAFE(item,
-			ext4_xattr_tree,
-			&xattr_ref->root,
-			save_item) {
+	RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
+	{
 		RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 		ext4_xattr_item_free(item);
 	}
 	xattr_ref->ea_size = 0;
 }
 
-int ext4_fs_get_xattr_ref(struct ext4_fs *fs,
-			  struct ext4_inode_ref *inode_ref,
+static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
+{
+	int ret = EOK;
+
+	ext4_fsblk_t xattr_block = 0;
+	xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
+					      &xattr_ref->fs->sb);
+	if (!xattr_block) {
+		ext4_fsblk_t goal =
+			ext4_fs_inode_to_goal_block(xattr_ref->inode_ref);
+
+		ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
+					      goal,
+					      &xattr_block);
+		if (ret != EOK)
+			goto Finish;
+
+		ret = ext4_trans_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
+				     xattr_block);
+		if (ret != EOK) {
+			ext4_balloc_free_block(xattr_ref->inode_ref,
+					       xattr_block);
+			goto Finish;
+		}
+
+		ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
+					&xattr_ref->fs->sb, xattr_block);
+		xattr_ref->inode_ref->dirty = true;
+		xattr_ref->block_loaded = true;
+	}
+
+Finish:
+	return ret;
+}
+
+static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
+{
+	ext4_fsblk_t xattr_block;
+	xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
+					      &xattr_ref->fs->sb);
+	ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
+				0);
+	ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
+	ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
+	xattr_ref->inode_ref->dirty = true;
+	xattr_ref->block_loaded = false;
+}
+
+static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
+{
+	struct ext4_xattr_header *block_header = NULL;
+	block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
+
+	memset(block_header, 0, sizeof(struct ext4_xattr_header));
+	block_header->h_magic = EXT4_XATTR_MAGIC;
+	block_header->h_refcount = to_le32(1);
+	block_header->h_blocks = to_le32(1);
+}
+
+static void
+ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
+			   struct ext4_xattr_ibody_header *ibody_header,
+			   struct ext4_xattr_entry *entry, void *ibody_data_ptr)
+{
+	entry->e_name_len = to_le32(item->name_len);
+	entry->e_name_index = item->name_index;
+	entry->e_value_offs =
+	    (char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header);
+	entry->e_value_block = 0;
+	entry->e_value_size = item->data_size;
+}
+
+static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
+				       struct ext4_xattr_header *block_header,
+				       struct ext4_xattr_entry *block_entry,
+				       void *block_data_ptr)
+{
+	block_entry->e_name_len = to_le32(item->name_len);
+	block_entry->e_name_index = item->name_index;
+	block_entry->e_value_offs =
+	    (char *)block_data_ptr - (char *)block_header;
+	block_entry->e_value_block = 0;
+	block_entry->e_value_size = item->data_size;
+}
+
+static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
+{
+	int ret = EOK;
+	bool block_modified = false;
+	void *ibody_data = NULL;
+	void *block_data = NULL;
+	struct ext4_xattr_item *item, *save_item;
+	size_t inode_size_rem, block_size_rem;
+	struct ext4_xattr_ibody_header *ibody_header = NULL;
+	struct ext4_xattr_header *block_header = NULL;
+	struct ext4_xattr_entry *entry = NULL;
+	struct ext4_xattr_entry *block_entry = NULL;
+
+	inode_size_rem = ext4_xattr_inode_space(xattr_ref);
+	block_size_rem = ext4_xattr_block_space(xattr_ref);
+	if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
+		ibody_header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
+		entry = EXT4_XATTR_IFIRST(ibody_header);
+	}
+
+	if (!xattr_ref->dirty)
+		goto Finish;
+	/* If there are enough spaces in the ibody EA table.*/
+	if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
+		memset(ibody_header, 0, inode_size_rem);
+		ibody_header->h_magic = EXT4_XATTR_MAGIC;
+		ibody_data = (char *)ibody_header + inode_size_rem;
+		inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
+
+		xattr_ref->inode_ref->dirty = true;
+	}
+	/* If we need an extra block to hold the EA entries*/
+	if (xattr_ref->ea_size > inode_size_rem) {
+		if (!xattr_ref->block_loaded) {
+			ret = ext4_xattr_try_alloc_block(xattr_ref);
+			if (ret != EOK)
+				goto Finish;
+		}
+		block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
+		block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
+		ext4_xattr_set_block_header(xattr_ref);
+		block_data = (char *)block_header + block_size_rem;
+		block_size_rem -= sizeof(struct ext4_xattr_header);
+
+		ext4_trans_set_block_dirty(xattr_ref->block.buf);
+	} else {
+		/* We don't need an extra block.*/
+		if (xattr_ref->block_loaded) {
+			block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
+			block_header->h_refcount =
+			    to_le32(to_le32(block_header->h_refcount) - 1);
+			if (!block_header->h_refcount) {
+				ext4_xattr_try_free_block(xattr_ref);
+				block_header = NULL;
+			} else {
+				block_entry =
+				    EXT4_XATTR_BFIRST(&xattr_ref->block);
+				block_data =
+				    (char *)block_header + block_size_rem;
+				block_size_rem -=
+				    sizeof(struct ext4_xattr_header);
+				ext4_inode_set_file_acl(
+				    xattr_ref->inode_ref->inode,
+				    &xattr_ref->fs->sb, 0);
+
+				xattr_ref->inode_ref->dirty = true;
+				ext4_trans_set_block_dirty(xattr_ref->block.buf);
+			}
+		}
+	}
+	RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
+	{
+		if (EXT4_XATTR_SIZE(item->data_size) +
+			EXT4_XATTR_LEN(item->name_len) <=
+		    inode_size_rem) {
+			ibody_data = (char *)ibody_data -
+				     EXT4_XATTR_SIZE(item->data_size);
+			ext4_xattr_set_inode_entry(item, ibody_header, entry,
+						   ibody_data);
+			memcpy(EXT4_XATTR_NAME(entry), item->name,
+			       item->name_len);
+			memcpy(ibody_data, item->data, item->data_size);
+			entry = EXT4_XATTR_NEXT(entry);
+			inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
+					  EXT4_XATTR_LEN(item->name_len);
+
+			xattr_ref->inode_ref->dirty = true;
+			continue;
+		}
+		if (EXT4_XATTR_SIZE(item->data_size) +
+			EXT4_XATTR_LEN(item->name_len) >
+		    block_size_rem) {
+			ret = ENOSPC;
+			goto Finish;
+		}
+		block_data =
+		    (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
+		ext4_xattr_set_block_entry(item, block_header, block_entry,
+					   block_data);
+		memcpy(EXT4_XATTR_NAME(block_entry), item->name,
+		       item->name_len);
+		memcpy(block_data, item->data, item->data_size);
+		block_entry = EXT4_XATTR_NEXT(block_entry);
+		block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
+				  EXT4_XATTR_LEN(item->name_len);
+
+		block_modified = true;
+	}
+	xattr_ref->dirty = false;
+	if (block_modified) {
+		ext4_xattr_rehash(block_header,
+				  EXT4_XATTR_BFIRST(&xattr_ref->block));
+		ext4_xattr_set_block_checksum(xattr_ref->inode_ref,
+					      xattr_ref->block.lb_id,
+					      block_header);
+		ext4_trans_set_block_dirty(xattr_ref->block.buf);
+	}
+
+Finish:
+	return ret;
+}
+
+void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
+			   int (*iter)(struct ext4_xattr_ref *ref,
+				     struct ext4_xattr_item *item))
+{
+	struct ext4_xattr_item *item;
+	if (!ref->iter_from)
+		ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
+
+	RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
+	{
+		int ret = EXT4_XATTR_ITERATE_CONT;
+		if (iter)
+			iter(ref, item);
+
+		if (ret != EXT4_XATTR_ITERATE_CONT) {
+			if (ret == EXT4_XATTR_ITERATE_STOP)
+				ref->iter_from = NULL;
+
+			break;
+		}
+	}
+}
+
+void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
+{
+	ref->iter_from = NULL;
+}
+
+int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
+		      const char *name, size_t name_len, const void *data,
+		      size_t data_size, bool replace)
+{
+	int ret = EOK;
+	struct ext4_xattr_item *item =
+	    ext4_xattr_lookup_item(ref, name_index, name, name_len);
+	if (replace) {
+		if (!item) {
+			ret = ENODATA;
+			goto Finish;
+		}
+		if (item->data_size != data_size)
+			ret = ext4_xattr_resize_item(ref, item, data_size);
+
+		if (ret != EOK) {
+			goto Finish;
+		}
+		memcpy(item->data, data, data_size);
+	} else {
+		if (item) {
+			ret = EEXIST;
+			goto Finish;
+		}
+		item = ext4_xattr_insert_item(ref, name_index, name, name_len,
+					      data, data_size);
+		if (!item)
+			ret = ENOMEM;
+	}
+Finish:
+	return ret;
+}
+
+int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
+			 const char *name, size_t name_len)
+{
+	return ext4_xattr_remove_item(ref, name_index, name, name_len);
+}
+
+int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
+		      const char *name, size_t name_len, void *buf,
+		      size_t buf_size, size_t *data_size)
+{
+	int ret = EOK;
+	size_t item_size = 0;
+	struct ext4_xattr_item *item =
+	    ext4_xattr_lookup_item(ref, name_index, name, name_len);
+
+	if (!item) {
+		ret = ENODATA;
+		goto Finish;
+	}
+	item_size = item->data_size;
+	if (buf_size > item_size)
+		buf_size = item_size;
+
+	if (buf)
+		memcpy(buf, item->data, buf_size);
+
+Finish:
+	if (data_size)
+		*data_size = item_size;
+
+	return ret;
+}
+
+int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 			  struct ext4_xattr_ref *ref)
 {
 	int rc;
-	uint64_t xattr_block;
-	xattr_block = ext4_inode_get_file_acl(inode_ref->inode,
-					      &fs->sb);
+	ext4_fsblk_t xattr_block;
+	xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 	RB_INIT(&ref->root);
+	ref->ea_size = 0;
+	ref->iter_from = NULL;
 	if (xattr_block) {
-		rc = ext4_block_get(fs->bdev,
-				    &inode_ref->block, xattr_block);
+		rc = ext4_trans_block_get(fs->bdev, &ref->block, xattr_block);
 		if (rc != EOK)
 			return EIO;
-	
+
 		ref->block_loaded = true;
 	} else
 		ref->block_loaded = false;
@@ -309,6 +862,7 @@ int ext4_fs_get_xattr_ref(struct ext4_fs *fs,
 
 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
 {
+	ext4_xattr_write_to_disk(ref);
 	if (ref->block_loaded) {
 		ext4_block_set(ref->fs->bdev, &ref->block);
 		ref->block_loaded = false;
@@ -318,3 +872,71 @@ void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
 	ref->fs = NULL;
 }
 
+struct xattr_prefix {
+	const char *prefix;
+	uint8_t name_index;
+};
+
+static const struct xattr_prefix prefix_tbl[] = {
+    {"user.", EXT4_XATTR_INDEX_USER},
+    {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
+    {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
+    {"trusted.", EXT4_XATTR_INDEX_TRUSTED},
+    {"security.", EXT4_XATTR_INDEX_SECURITY},
+    {"system.", EXT4_XATTR_INDEX_SYSTEM},
+    {"system.richacl", EXT4_XATTR_INDEX_RICHACL},
+    {NULL, 0},
+};
+
+const char *ext4_extract_xattr_name(const char *full_name, size_t full_name_len,
+			      uint8_t *name_index, size_t *name_len)
+{
+	int i;
+	ext4_assert(name_index);
+	if (!full_name_len) {
+		if (name_len)
+			*name_len = 0;
+
+		return NULL;
+	}
+
+	for (i = 0; prefix_tbl[i].prefix; i++) {
+		size_t prefix_len = strlen(prefix_tbl[i].prefix);
+		if (full_name_len >= prefix_len &&
+		    !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
+			*name_index = prefix_tbl[i].name_index;
+			if (name_len)
+				*name_len = full_name_len - prefix_len;
+
+			return full_name + prefix_len;
+		}
+	}
+	if (name_len)
+		*name_len = 0;
+
+	return NULL;
+}
+
+const char *ext4_get_xattr_name_prefix(uint8_t name_index,
+				       size_t *ret_prefix_len)
+{
+	int i;
+
+	for (i = 0; prefix_tbl[i].prefix; i++) {
+		size_t prefix_len = strlen(prefix_tbl[i].prefix);
+		if (prefix_tbl[i].name_index == name_index) {
+			if (ret_prefix_len)
+				*ret_prefix_len = prefix_len;
+
+			return prefix_tbl[i].prefix;
+		}
+	}
+	if (ret_prefix_len)
+		*ret_prefix_len = 0;
+
+	return NULL;
+}
+
+/**
+ * @}
+ */