[Patch 1/2] ioctl and uninitialized extents

["Amit K. Arora" <aarora@linux.vnet.ibm.com>]

This patch implements the ioctl which may be used for persistent
preallocation of blocks to an extent enabled file in ext4.

Signed-off-by: Amit Arora <aarora@in.ibm.com>
---
 fs/ext4/extents.c               |  125 ++++++++++++++++++++++++++--------------
 fs/ext4/ioctl.c                 |   69 ++++++++++++++++++++++
 include/linux/ext4_fs.h         |   13 ++++
 include/linux/ext4_fs_extents.h |   13 ++++
 4 files changed, 177 insertions(+), 43 deletions(-)

Index: linux-2.6.20-rc5/fs/ext4/extents.c
===================================================================
--- linux-2.6.20-rc5.orig/fs/ext4/extents.c
+++ linux-2.6.20-rc5/fs/ext4/extents.c
@@ -283,7 +283,7 @@ static void ext4_ext_show_path(struct in
 		} else if (path->p_ext) {
 			ext_debug("  %d:%d:%llu ",
 				  le32_to_cpu(path->p_ext->ee_block),
-				  le16_to_cpu(path->p_ext->ee_len),
+				  ext4_ext_get_actual_len(path->p_ext),
 				  ext_pblock(path->p_ext));
 		} else
 			ext_debug("  []");
@@ -306,7 +306,7 @@ static void ext4_ext_show_leaf(struct in
 
 	for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 		ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block),
-			  le16_to_cpu(ex->ee_len), ext_pblock(ex));
+			  	ext4_ext_get_actual_len(ex), ext_pblock(ex));
 	}
 	ext_debug("\n");
 }
@@ -426,7 +426,7 @@ ext4_ext_binsearch(struct inode *inode, 
 	ext_debug("  -> %d:%llu:%d ",
 		        le32_to_cpu(path->p_ext->ee_block),
 		        ext_pblock(path->p_ext),
-			le16_to_cpu(path->p_ext->ee_len));
+			ext4_ext_get_actual_len(path->p_ext));
 
 #ifdef CHECK_BINSEARCH
 	{
@@ -687,7 +687,7 @@ static int ext4_ext_split(handle_t *hand
 		ext_debug("move %d:%llu:%d in new leaf %llu\n",
 			        le32_to_cpu(path[depth].p_ext->ee_block),
 			        ext_pblock(path[depth].p_ext),
-			        le16_to_cpu(path[depth].p_ext->ee_len),
+				ext4_ext_get_actual_len(path[depth].p_ext),
 				newblock);
 		/*memmove(ex++, path[depth].p_ext++,
 				sizeof(struct ext4_extent));
@@ -1107,7 +1107,19 @@ static int
 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
 				struct ext4_extent *ex2)
 {
-	if (le32_to_cpu(ex1->ee_block) + le16_to_cpu(ex1->ee_len) !=
+	unsigned short ext1_ee_len, ext2_ee_len;
+
+	/*
+	 * Make sure that either both extents are uninitialized, or
+	 * both are _not_.
+	 */
+	if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
+		return 0;
+
+	ext1_ee_len = ext4_ext_get_actual_len(ex1);
+	ext2_ee_len = ext4_ext_get_actual_len(ex2);
+
+	if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
 			le32_to_cpu(ex2->ee_block))
 		return 0;
 
@@ -1116,14 +1128,14 @@ ext4_can_extents_be_merged(struct inode 
 	 * as an RO_COMPAT feature, refuse to merge to extents if
 	 * this can result in the top bit of ee_len being set.
 	 */
-	if (le16_to_cpu(ex1->ee_len) + le16_to_cpu(ex2->ee_len) > EXT_MAX_LEN)
+	if (ext1_ee_len + ext2_ee_len > EXT_MAX_LEN)
 		return 0;
 #ifdef AGRESSIVE_TEST
 	if (le16_to_cpu(ex1->ee_len) >= 4)
 		return 0;
 #endif
 
-	if (ext_pblock(ex1) + le16_to_cpu(ex1->ee_len) == ext_pblock(ex2))
+	if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2))
 		return 1;
 	return 0;
 }
@@ -1145,7 +1157,7 @@ unsigned int ext4_ext_check_overlap(stru
 	unsigned int depth, len1;
 
 	b1 = le32_to_cpu(newext->ee_block);
-	len1 = le16_to_cpu(newext->ee_len);
+	len1 = ext4_ext_get_actual_len(newext);
 	depth = ext_depth(inode);
 	if (!path[depth].p_ext)
 		goto out;
@@ -1181,9 +1193,9 @@ int ext4_ext_insert_extent(handle_t *han
 	struct ext4_extent *ex, *fex;
 	struct ext4_extent *nearex; /* nearest extent */
 	struct ext4_ext_path *npath = NULL;
-	int depth, len, err, next;
+	int depth, len, err, next, uninitialized = 0;
 
-	BUG_ON(newext->ee_len == 0);
+	BUG_ON(ext4_ext_get_actual_len(newext) == 0);
 	depth = ext_depth(inode);
 	ex = path[depth].p_ext;
 	BUG_ON(path[depth].p_hdr == NULL);
@@ -1191,14 +1203,23 @@ int ext4_ext_insert_extent(handle_t *han
 	/* try to insert block into found extent and return */
 	if (ex && ext4_can_extents_be_merged(inode, ex, newext)) {
 		ext_debug("append %d block to %d:%d (from %llu)\n",
-				le16_to_cpu(newext->ee_len),
+				ext4_ext_get_actual_len(newext),
 				le32_to_cpu(ex->ee_block),
-				le16_to_cpu(ex->ee_len), ext_pblock(ex));
+				ext4_ext_get_actual_len(ex), ext_pblock(ex));
 		err = ext4_ext_get_access(handle, inode, path + depth);
 		if (err)
 			return err;
-		ex->ee_len = cpu_to_le16(le16_to_cpu(ex->ee_len)
-					 + le16_to_cpu(newext->ee_len));
+
+		/* ext4_can_extents_be_merged should have checked that either
+		 * both extents are uninitialized, or both aren't. Thus we
+		 * need to check only one of them here.
+		 */
+		if (ext4_ext_is_uninitialized(ex))
+			uninitialized = 1;
+		ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
+					+ ext4_ext_get_actual_len(newext));
+		if (uninitialized)
+			ext4_ext_mark_uninitialized(ex);
 		eh = path[depth].p_hdr;
 		nearex = ex;
 		goto merge;
@@ -1254,7 +1275,7 @@ has_space:
 		ext_debug("first extent in the leaf: %d:%llu:%d\n",
 			        le32_to_cpu(newext->ee_block),
 			        ext_pblock(newext),
-			        le16_to_cpu(newext->ee_len));
+				ext4_ext_get_actual_len(newext));
 		path[depth].p_ext = EXT_FIRST_EXTENT(eh);
 	} else if (le32_to_cpu(newext->ee_block)
 		           > le32_to_cpu(nearex->ee_block)) {
@@ -1267,7 +1288,7 @@ has_space:
 					"move %d from 0x%p to 0x%p\n",
 				        le32_to_cpu(newext->ee_block),
 				        ext_pblock(newext),
-				        le16_to_cpu(newext->ee_len),
+					ext4_ext_get_actual_len(newext),
 					nearex, len, nearex + 1, nearex + 2);
 			memmove(nearex + 2, nearex + 1, len);
 		}
@@ -1280,7 +1301,7 @@ has_space:
 				"move %d from 0x%p to 0x%p\n",
 				le32_to_cpu(newext->ee_block),
 				ext_pblock(newext),
-				le16_to_cpu(newext->ee_len),
+				ext4_ext_get_actual_len(newext),
 				nearex, len, nearex + 1, nearex + 2);
 		memmove(nearex + 1, nearex, len);
 		path[depth].p_ext = nearex;
@@ -1299,8 +1320,13 @@ merge:
 		if (!ext4_can_extents_be_merged(inode, nearex, nearex + 1))
 			break;
 		/* merge with next extent! */
-		nearex->ee_len = cpu_to_le16(le16_to_cpu(nearex->ee_len)
-					     + le16_to_cpu(nearex[1].ee_len));
+		if (ext4_ext_is_uninitialized(nearex))
+			uninitialized = 1;
+		nearex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(nearex)
+					+ ext4_ext_get_actual_len(nearex + 1));
+		if (uninitialized)
+			ext4_ext_mark_uninitialized(nearex);
+
 		if (nearex + 1 < EXT_LAST_EXTENT(eh)) {
 			len = (EXT_LAST_EXTENT(eh) - nearex - 1)
 					* sizeof(struct ext4_extent);
@@ -1370,8 +1396,8 @@ int ext4_ext_walk_space(struct inode *in
 			end = le32_to_cpu(ex->ee_block);
 			if (block + num < end)
 				end = block + num;
-		} else if (block >=
-			     le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len)) {
+		} else if (block >= le32_to_cpu(ex->ee_block)
+					+ ext4_ext_get_actual_len(ex)) {
 			/* need to allocate space after found extent */
 			start = block;
 			end = block + num;
@@ -1383,7 +1409,8 @@ int ext4_ext_walk_space(struct inode *in
 			 * by found extent
 			 */
 			start = block;
-			end = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len);
+			end = le32_to_cpu(ex->ee_block)
+				+ ext4_ext_get_actual_len(ex);
 			if (block + num < end)
 				end = block + num;
 			exists = 1;
@@ -1399,7 +1426,7 @@ int ext4_ext_walk_space(struct inode *in
 			cbex.ec_type = EXT4_EXT_CACHE_GAP;
 		} else {
 		        cbex.ec_block = le32_to_cpu(ex->ee_block);
-		        cbex.ec_len = le16_to_cpu(ex->ee_len);
+			cbex.ec_len = ext4_ext_get_actual_len(ex);
 		        cbex.ec_start = ext_pblock(ex);
 			cbex.ec_type = EXT4_EXT_CACHE_EXTENT;
 		}
@@ -1472,15 +1499,15 @@ ext4_ext_put_gap_in_cache(struct inode *
 		ext_debug("cache gap(before): %lu [%lu:%lu]",
 				(unsigned long) block,
 			        (unsigned long) le32_to_cpu(ex->ee_block),
-			        (unsigned long) le16_to_cpu(ex->ee_len));
+			        (unsigned long) ext4_ext_get_actual_len(ex));
 	} else if (block >= le32_to_cpu(ex->ee_block)
-		            + le16_to_cpu(ex->ee_len)) {
+		            + ext4_ext_get_actual_len(ex)) {
 	        lblock = le32_to_cpu(ex->ee_block)
-		         + le16_to_cpu(ex->ee_len);
+		         + ext4_ext_get_actual_len(ex);
 		len = ext4_ext_next_allocated_block(path);
 		ext_debug("cache gap(after): [%lu:%lu] %lu",
 			        (unsigned long) le32_to_cpu(ex->ee_block),
-			        (unsigned long) le16_to_cpu(ex->ee_len),
+			        (unsigned long) ext4_ext_get_actual_len(ex),
 				(unsigned long) block);
 		BUG_ON(len == lblock);
 		len = len - lblock;
@@ -1610,12 +1637,12 @@ static int ext4_remove_blocks(handle_t *
 				unsigned long from, unsigned long to)
 {
 	struct buffer_head *bh;
+	unsigned short ee_len =  ext4_ext_get_actual_len(ex);
 	int i;
 
 #ifdef EXTENTS_STATS
 	{
 		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
-		unsigned short ee_len =  le16_to_cpu(ex->ee_len);
 		spin_lock(&sbi->s_ext_stats_lock);
 		sbi->s_ext_blocks += ee_len;
 		sbi->s_ext_extents++;
@@ -1629,12 +1656,12 @@ static int ext4_remove_blocks(handle_t *
 	}
 #endif
 	if (from >= le32_to_cpu(ex->ee_block)
-	    && to == le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) {
+	    && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
 		/* tail removal */
 		unsigned long num;
 		ext4_fsblk_t start;
-		num = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - from;
-		start = ext_pblock(ex) + le16_to_cpu(ex->ee_len) - num;
+		num = le32_to_cpu(ex->ee_block) + ee_len - from;
+		start = ext_pblock(ex) + ee_len - num;
 		ext_debug("free last %lu blocks starting %llu\n", num, start);
 		for (i = 0; i < num; i++) {
 			bh = sb_find_get_block(inode->i_sb, start + i);
@@ -1642,12 +1669,12 @@ static int ext4_remove_blocks(handle_t *
 		}
 		ext4_free_blocks(handle, inode, start, num);
 	} else if (from == le32_to_cpu(ex->ee_block)
-		   && to <= le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) {
+		   && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
 		printk("strange request: removal %lu-%lu from %u:%u\n",
-		       from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len));
+			from, to, le32_to_cpu(ex->ee_block), ee_len);
 	} else {
 		printk("strange request: removal(2) %lu-%lu from %u:%u\n",
-		       from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len));
+			from, to, le32_to_cpu(ex->ee_block), ee_len);
 	}
 	return 0;
 }
@@ -1661,7 +1688,7 @@ ext4_ext_rm_leaf(handle_t *handle, struc
 	struct ext4_extent_header *eh;
 	unsigned a, b, block, num;
 	unsigned long ex_ee_block;
-	unsigned short ex_ee_len;
+	unsigned short ex_ee_len, uninitialized = 0;
 	struct ext4_extent *ex;
 
 	ext_debug("truncate since %lu in leaf\n", start);
@@ -1676,7 +1703,9 @@ ext4_ext_rm_leaf(handle_t *handle, struc
 	ex = EXT_LAST_EXTENT(eh);
 
 	ex_ee_block = le32_to_cpu(ex->ee_block);
-	ex_ee_len = le16_to_cpu(ex->ee_len);
+	if (ext4_ext_is_uninitialized(ex))
+		uninitialized = 1;
+	ex_ee_len = ext4_ext_get_actual_len(ex);
 
 	while (ex >= EXT_FIRST_EXTENT(eh) &&
 			ex_ee_block + ex_ee_len > start) {
@@ -1744,6 +1773,8 @@ ext4_ext_rm_leaf(handle_t *handle, struc
 
 		ex->ee_block = cpu_to_le32(block);
 		ex->ee_len = cpu_to_le16(num);
+		if (uninitialized)
+			ext4_ext_mark_uninitialized(ex);
 
 		err = ext4_ext_dirty(handle, inode, path + depth);
 		if (err)
@@ -1753,7 +1784,7 @@ ext4_ext_rm_leaf(handle_t *handle, struc
 				ext_pblock(ex));
 		ex--;
 		ex_ee_block = le32_to_cpu(ex->ee_block);
-		ex_ee_len = le16_to_cpu(ex->ee_len);
+		ex_ee_len = ext4_ext_get_actual_len(ex);
 	}
 
 	if (correct_index && eh->eh_entries)
@@ -2029,7 +2060,7 @@ int ext4_ext_get_blocks(handle_t *handle
 	if (ex) {
 	        unsigned long ee_block = le32_to_cpu(ex->ee_block);
 		ext4_fsblk_t ee_start = ext_pblock(ex);
-		unsigned short ee_len  = le16_to_cpu(ex->ee_len);
+		unsigned short ee_len;
 
 		/*
 		 * Allow future support for preallocated extents to be added
@@ -2037,8 +2068,9 @@ int ext4_ext_get_blocks(handle_t *handle
 		 * Uninitialized extents are treated as holes, except that
 		 * we avoid (fail) allocating new blocks during a write.
 		 */
-		if (ee_len > EXT_MAX_LEN)
+		if (le16_to_cpu(ex->ee_len) > EXT_MAX_LEN)
 			goto out2;
+		ee_len = ext4_ext_get_actual_len(ex);
 		/* if found extent covers block, simply return it */
 	        if (iblock >= ee_block && iblock < ee_block + ee_len) {
 			newblock = iblock - ee_block + ee_start;
@@ -2046,8 +2078,11 @@ int ext4_ext_get_blocks(handle_t *handle
 			allocated = ee_len - (iblock - ee_block);
 			ext_debug("%d fit into %lu:%d -> %llu\n", (int) iblock,
 					ee_block, ee_len, newblock);
-			ext4_ext_put_in_cache(inode, ee_block, ee_len,
-						ee_start, EXT4_EXT_CACHE_EXTENT);
+			/* Do not put uninitialized extent in the cache */
+			if (!ext4_ext_is_uninitialized(ex))
+				ext4_ext_put_in_cache(inode, ee_block,
+							ee_len, ee_start,
+							EXT4_EXT_CACHE_EXTENT);
 			goto out;
 		}
 	}
@@ -2089,6 +2124,8 @@ int ext4_ext_get_blocks(handle_t *handle
 	/* try to insert new extent into found leaf and return */
 	ext4_ext_store_pblock(&newex, newblock);
 	newex.ee_len = cpu_to_le16(allocated);
+	if (create == EXT4_CREATE_UNINITIALIZED_EXT)  /* Mark uninitialized */
+		ext4_ext_mark_uninitialized(&newex);
 	err = ext4_ext_insert_extent(handle, inode, path, &newex);
 	if (err)
 		goto out2;
@@ -2100,8 +2137,10 @@ int ext4_ext_get_blocks(handle_t *handle
 	newblock = ext_pblock(&newex);
 	__set_bit(BH_New, &bh_result->b_state);
 
-	ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
-				EXT4_EXT_CACHE_EXTENT);
+	/* Cache only when it is _not_ an uninitialized extent */
+	if (create!=EXT4_CREATE_UNINITIALIZED_EXT)
+		ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
+						EXT4_EXT_CACHE_EXTENT);
 out:
 	if (allocated > max_blocks)
 		allocated = max_blocks;
Index: linux-2.6.20-rc5/fs/ext4/ioctl.c
===================================================================
--- linux-2.6.20-rc5.orig/fs/ext4/ioctl.c
+++ linux-2.6.20-rc5/fs/ext4/ioctl.c
@@ -11,6 +11,7 @@
 #include <linux/jbd2.h>
 #include <linux/capability.h>
 #include <linux/ext4_fs.h>
+#include <linux/ext4_fs_extents.h>
 #include <linux/ext4_jbd2.h>
 #include <linux/time.h>
 #include <linux/compat.h>
@@ -248,6 +249,74 @@ flags_err:
 		return err;
 	}
 
+	case EXT4_IOC_PREALLOCATE: {
+		struct ext4_falloc_input input;
+		handle_t *handle;
+		ext4_fsblk_t block, max_blocks;
+		int ret, ret2, nblocks = 0, retries = 0;
+		struct buffer_head map_bh;
+		unsigned int credits, blkbits = inode->i_blkbits;
+
+		if (IS_RDONLY(inode))
+			return -EROFS;
+
+		if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
+			return -ENOTTY;
+
+		if (copy_from_user(&input,
+			(struct ext4_falloc_input __user *) arg, sizeof(input)))
+			return -EFAULT;
+
+		if (input.len == 0)
+			return -EINVAL;
+
+		block = input.offset >> blkbits;
+		max_blocks = (EXT4_BLOCK_ALIGN(input.len + input.offset,
+						blkbits) >> blkbits) - block;
+		mutex_lock(&EXT4_I(inode)->truncate_mutex);
+		credits = ext4_ext_calc_credits_for_insert(inode, NULL);
+		mutex_unlock(&EXT4_I(inode)->truncate_mutex);
+		handle=ext4_journal_start(inode, credits +
+					EXT4_DATA_TRANS_BLOCKS(inode->i_sb)+1);
+		if (IS_ERR(handle))
+			return PTR_ERR(handle);
+retry:
+		ret = 0;
+		while (ret >= 0 && ret < max_blocks) {
+			block = block + ret;
+			max_blocks = max_blocks - ret;
+	  		ret = ext4_ext_get_blocks(handle, inode, block,
+						max_blocks, &map_bh,
+						EXT4_CREATE_UNINITIALIZED_EXT,
+						0);
+			BUG_ON(!ret);
+			if (ret > 0 && test_bit(BH_New, &map_bh.b_state)
+			    && ((block + ret) << blkbits) > i_size_read(inode))
+				nblocks = nblocks + ret;
+		}
+		if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb,
+								&retries))
+			goto retry;
+
+		if (nblocks) {
+			mutex_lock(&inode->i_mutex);
+			if (!i_size_read(inode) && ret > 0)
+				i_size_write(inode, (block + ret) << blkbits);
+			else
+				i_size_write(inode, i_size_read(inode) +
+							(nblocks << blkbits));
+			EXT4_I(inode)->i_disksize = i_size_read(inode);
+			mutex_unlock(&inode->i_mutex);
+		}
+
+		ext4_mark_inode_dirty(handle, inode);
+		ret2 = ext4_journal_stop(handle);
+		if (ret > 0)
+			ret = ret2;
+
+		return ret > 0 ? 0 : ret;
+	}
+
 	default:
 		return -ENOTTY;
 	}
Index: linux-2.6.20-rc5/include/linux/ext4_fs.h
===================================================================
--- linux-2.6.20-rc5.orig/include/linux/ext4_fs.h
+++ linux-2.6.20-rc5/include/linux/ext4_fs.h
@@ -102,6 +102,8 @@
 				 EXT4_GOOD_OLD_FIRST_INO : \
 				 (s)->s_first_ino)
 #endif
+#define EXT4_BLOCK_ALIGN(size, blkbits) 	(((size)+(1 << blkbits)-1) & \
+							(~((1 << blkbits)-1)))
 
 /*
  * Macro-instructions used to manage fragments
@@ -225,6 +227,16 @@ struct ext4_new_group_data {
 	__u32 free_blocks_count;
 };
 
+/* The struct ext4_falloc_input in kernel, for EXT4_IOC_PREALLOCATE */
+struct ext4_falloc_input {
+	__u64 offset;
+	__u64 len;
+};
+
+/* Following is used by preallocation logic to tell get_blocks() that we
+ * want uninitialzed extents.
+ */
+#define EXT4_CREATE_UNINITIALIZED_EXT		2
 
 /*
  * ioctl commands
@@ -242,6 +254,7 @@ struct ext4_new_group_data {
 #endif
 #define EXT4_IOC_GETRSVSZ		_IOR('f', 5, long)
 #define EXT4_IOC_SETRSVSZ		_IOW('f', 6, long)
+#define EXT4_IOC_PREALLOCATE		_IOW('f', 9, struct ext4_falloc_input)
 
 /*
  * ioctl commands in 32 bit emulation
Index: linux-2.6.20-rc5/include/linux/ext4_fs_extents.h
===================================================================
--- linux-2.6.20-rc5.orig/include/linux/ext4_fs_extents.h
+++ linux-2.6.20-rc5/include/linux/ext4_fs_extents.h
@@ -125,6 +125,19 @@ struct ext4_ext_path {
 #define EXT4_EXT_CACHE_EXTENT	2
 
 /*
+ * Macro-instructions to handle (mark/unmark/check/create) unitialized
+ * extents. Applications can issue an IOCTL for preallocation, which results
+ * in assigning unitialized extents to the file.
+ */
+#define ext4_ext_mark_uninitialized(ext)	((ext)->ee_len |= \
+							cpu_to_le16(0x8000))
+#define ext4_ext_is_uninitialized(ext)  	((le16_to_cpu((ext)->ee_len))& \
+									0x8000)
+#define ext4_ext_get_actual_len(ext)		((le16_to_cpu((ext)->ee_len))& \
+									0x7FFF)
+
+
+/*
  * to be called by ext4_ext_walk_space()
  * negative retcode - error
  * positive retcode - signal for ext4_ext_walk_space(), see below