ext4: fix ext4_fsymlink creation
[lwext4.git] / src / ext4_extent.c
index f53733d10d9073f3cf4367b3ab8cc677e0127c90..abac59bcb6dcc56fdac87c619a6687eb080fe509 100644 (file)
@@ -1,46 +1,33 @@
 /*
- * Copyright (c) 2015 Grzegorz Kostka (kostka.grzegorz@gmail.com)
- * Copyright (c) 2015 Kaho Ng (ngkaho1234@gmail.com)
+ * Copyright (c) 2017 Grzegorz Kostka (kostka.grzegorz@gmail.com)
+ * Copyright (c) 2017 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.
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
  */
 
-#include "ext4_config.h"
-#include "ext4_blockdev.h"
-#include "ext4_fs.h"
-#include "ext4_super.h"
-#include "ext4_crc32.h"
-#include "ext4_balloc.h"
-#include "ext4_debug.h"
+#include <ext4_config.h>
+#include <ext4_types.h>
+#include <ext4_misc.h>
+#include <ext4_errno.h>
+#include <ext4_debug.h>
+
+#include <ext4_blockdev.h>
+#include <ext4_trans.h>
+#include <ext4_fs.h>
+#include <ext4_super.h>
+#include <ext4_crc32.h>
+#include <ext4_balloc.h>
+#include <ext4_extent.h>
 
 #include <stdlib.h>
 #include <string.h>
 #include <inttypes.h>
 #include <stddef.h>
 
-#include "ext4_extent.h"
-
+#if CONFIG_EXTENTS_ENABLE
 /*
  * used by extent splitting.
  */
 #define EXT4_EXT_DATA_VALID2 0x10  /* second half contains valid data */
 #define EXT4_EXT_NO_COMBINE 0x20   /* do not combine two extents */
 
+#define EXT4_EXT_UNWRITTEN_MASK (1L << 15)
+
+#define EXT4_EXT_MAX_LEN_WRITTEN (1L << 15)
+#define EXT4_EXT_MAX_LEN_UNWRITTEN \
+    (EXT4_EXT_MAX_LEN_WRITTEN - 1)
+
+#define EXT4_EXT_GET_LEN(ex) to_le16((ex)->block_count)
+#define EXT4_EXT_GET_LEN_UNWRITTEN(ex) \
+    (EXT4_EXT_GET_LEN(ex) & ~(EXT4_EXT_UNWRITTEN_MASK))
+#define EXT4_EXT_SET_LEN(ex, count) \
+    ((ex)->block_count = to_le16(count))
+
+#define EXT4_EXT_IS_UNWRITTEN(ex) \
+    (EXT4_EXT_GET_LEN(ex) > EXT4_EXT_MAX_LEN_WRITTEN)
+#define EXT4_EXT_SET_UNWRITTEN(ex) \
+    ((ex)->block_count |= to_le16(EXT4_EXT_UNWRITTEN_MASK))
+#define EXT4_EXT_SET_WRITTEN(ex) \
+    ((ex)->block_count &= ~(to_le16(EXT4_EXT_UNWRITTEN_MASK)))
+
+/*
+ * Array of ext4_ext_path contains path to some extent.
+ * Creation/lookup routines use it for traversal/splitting/etc.
+ * Truncate uses it to simulate recursive walking.
+ */
+struct ext4_extent_path {
+    ext4_fsblk_t p_block;
+    struct ext4_block block;
+    int32_t depth;
+    int32_t maxdepth;
+    struct ext4_extent_header *header;
+    struct ext4_extent_index *index;
+    struct ext4_extent *extent;
+};
+
+
+#pragma pack(push, 1)
+
+/*
+ * This is the extent tail on-disk structure.
+ * All other extent structures are 12 bytes long.  It turns out that
+ * block_size % 12 >= 4 for at least all powers of 2 greater than 512, which
+ * covers all valid ext4 block sizes.  Therefore, this tail structure can be
+ * crammed into the end of the block without having to rebalance the tree.
+ */
+struct ext4_extent_tail
+{
+    uint32_t et_checksum; /* crc32c(uuid+inum+extent_block) */
+};
+
+/*
+ * This is the extent on-disk structure.
+ * It's used at the bottom of the tree.
+ */
+struct ext4_extent {
+    uint32_t first_block; /* First logical block extent covers */
+    uint16_t block_count; /* Number of blocks covered by extent */
+    uint16_t start_hi;    /* High 16 bits of physical block */
+    uint32_t start_lo;    /* Low 32 bits of physical block */
+};
+
+/*
+ * This is index on-disk structure.
+ * It's used at all the levels except the bottom.
+ */
+struct ext4_extent_index {
+    uint32_t first_block; /* Index covers logical blocks from 'block' */
+
+    /**
+     * Pointer to the physical block of the next
+     * level. leaf or next index could be there
+     * high 16 bits of physical block
+     */
+    uint32_t leaf_lo;
+    uint16_t leaf_hi;
+    uint16_t padding;
+};
+
+/*
+ * Each block (leaves and indexes), even inode-stored has header.
+ */
+struct ext4_extent_header {
+    uint16_t magic;
+    uint16_t entries_count;     /* Number of valid entries */
+    uint16_t max_entries_count; /* Capacity of store in entries */
+    uint16_t depth;             /* Has tree real underlying blocks? */
+    uint32_t generation;    /* generation of the tree */
+};
+
+#pragma pack(pop)
+
+
+#define EXT4_EXTENT_MAGIC 0xF30A
+
+#define EXT4_EXTENT_FIRST(header)                                              \
+    ((struct ext4_extent *)(((char *)(header)) +                           \
+                sizeof(struct ext4_extent_header)))
+
+#define EXT4_EXTENT_FIRST_INDEX(header)                                        \
+    ((struct ext4_extent_index *)(((char *)(header)) +                     \
+                      sizeof(struct ext4_extent_header)))
+
+/*
+ * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
+ * initialized extent. This is 2^15 and not (2^16 - 1), since we use the
+ * MSB of ee_len field in the extent datastructure to signify if this
+ * particular extent is an initialized extent or an uninitialized (i.e.
+ * preallocated).
+ * EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an
+ * uninitialized extent.
+ * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
+ * uninitialized one. In other words, if MSB of ee_len is set, it is an
+ * uninitialized extent with only one special scenario when ee_len = 0x8000.
+ * In this case we can not have an uninitialized extent of zero length and
+ * thus we make it as a special case of initialized extent with 0x8000 length.
+ * This way we get better extent-to-group alignment for initialized extents.
+ * Hence, the maximum number of blocks we can have in an *initialized*
+ * extent is 2^15 (32768) and in an *uninitialized* extent is 2^15-1 (32767).
+ */
+#define EXT_INIT_MAX_LEN (1L << 15)
+#define EXT_UNWRITTEN_MAX_LEN (EXT_INIT_MAX_LEN - 1)
+
+#define EXT_EXTENT_SIZE sizeof(struct ext4_extent)
+#define EXT_INDEX_SIZE sizeof(struct ext4_extent_idx)
+
+#define EXT_FIRST_EXTENT(__hdr__)                                              \
+    ((struct ext4_extent *)(((char *)(__hdr__)) +                          \
+                sizeof(struct ext4_extent_header)))
+#define EXT_FIRST_INDEX(__hdr__)                                               \
+    ((struct ext4_extent_index *)(((char *)(__hdr__)) +                    \
+                    sizeof(struct ext4_extent_header)))
+#define EXT_HAS_FREE_INDEX(__path__)                                           \
+    (to_le16((__path__)->header->entries_count) <                                \
+                    to_le16((__path__)->header->max_entries_count))
+#define EXT_LAST_EXTENT(__hdr__)                                               \
+    (EXT_FIRST_EXTENT((__hdr__)) + to_le16((__hdr__)->entries_count) - 1)
+#define EXT_LAST_INDEX(__hdr__)                                                \
+    (EXT_FIRST_INDEX((__hdr__)) + to_le16((__hdr__)->entries_count) - 1)
+#define EXT_MAX_EXTENT(__hdr__)                                                \
+    (EXT_FIRST_EXTENT((__hdr__)) + to_le16((__hdr__)->max_entries_count) - 1)
+#define EXT_MAX_INDEX(__hdr__)                                                 \
+    (EXT_FIRST_INDEX((__hdr__)) + to_le16((__hdr__)->max_entries_count) - 1)
+
+#define EXT4_EXTENT_TAIL_OFFSET(hdr)                                           \
+    (sizeof(struct ext4_extent_header) +                                   \
+     (sizeof(struct ext4_extent) * to_le16((hdr)->max_entries_count)))
+
+
+/**@brief Get logical number of the block covered by extent.
+ * @param extent Extent to load number from
+ * @return Logical number of the first block covered by extent */
+static inline uint32_t ext4_extent_get_first_block(struct ext4_extent *extent)
+{
+    return to_le32(extent->first_block);
+}
+
+/**@brief Set logical number of the first block covered by extent.
+ * @param extent Extent to set number to
+ * @param iblock Logical number of the first block covered by extent */
+static inline void ext4_extent_set_first_block(struct ext4_extent *extent,
+        uint32_t iblock)
+{
+    extent->first_block = to_le32(iblock);
+}
+
+/**@brief Get number of blocks covered by extent.
+ * @param extent Extent to load count from
+ * @return Number of blocks covered by extent */
+static inline uint16_t ext4_extent_get_block_count(struct ext4_extent *extent)
+{
+    if (EXT4_EXT_IS_UNWRITTEN(extent))
+        return EXT4_EXT_GET_LEN_UNWRITTEN(extent);
+    else
+        return EXT4_EXT_GET_LEN(extent);
+}
+/**@brief Set number of blocks covered by extent.
+ * @param extent Extent to load count from
+ * @param count  Number of blocks covered by extent
+ * @param unwritten Whether the extent is unwritten or not */
+static inline void ext4_extent_set_block_count(struct ext4_extent *extent,
+                           uint16_t count, bool unwritten)
+{
+    EXT4_EXT_SET_LEN(extent, count);
+    if (unwritten)
+        EXT4_EXT_SET_UNWRITTEN(extent);
+}
+
+/**@brief Get physical number of the first block covered by extent.
+ * @param extent Extent to load number
+ * @return Physical number of the first block covered by extent */
+static inline uint64_t ext4_extent_get_start(struct ext4_extent *extent)
+{
+    return ((uint64_t)to_le16(extent->start_hi)) << 32 |
+           ((uint64_t)to_le32(extent->start_lo));
+}
+
+
+/**@brief Set physical number of the first block covered by extent.
+ * @param extent Extent to load number
+ * @param fblock Physical number of the first block covered by extent */
+static inline void ext4_extent_set_start(struct ext4_extent *extent, uint64_t fblock)
+{
+    extent->start_lo = to_le32((fblock << 32) >> 32);
+    extent->start_hi = to_le16((uint16_t)(fblock >> 32));
+}
+
+
+/**@brief Get logical number of the block covered by extent index.
+ * @param index Extent index to load number from
+ * @return Logical number of the first block covered by extent index */
+static inline uint32_t
+ext4_extent_index_get_first_block(struct ext4_extent_index *index)
+{
+    return to_le32(index->first_block);
+}
+
+/**@brief Set logical number of the block covered by extent index.
+ * @param index  Extent index to set number to
+ * @param iblock Logical number of the first block covered by extent index */
+static inline void
+ext4_extent_index_set_first_block(struct ext4_extent_index *index,
+                  uint32_t iblock)
+{
+    index->first_block = to_le32(iblock);
+}
+
+/**@brief Get physical number of block where the child node is located.
+ * @param index Extent index to load number from
+ * @return Physical number of the block with child node */
+static inline uint64_t
+ext4_extent_index_get_leaf(struct ext4_extent_index *index)
+{
+    return ((uint64_t)to_le16(index->leaf_hi)) << 32 |
+           ((uint64_t)to_le32(index->leaf_lo));
+}
+
+/**@brief Set physical number of block where the child node is located.
+ * @param index  Extent index to set number to
+ * @param fblock Ohysical number of the block with child node */
+static inline void ext4_extent_index_set_leaf(struct ext4_extent_index *index,
+                          uint64_t fblock)
+{
+    index->leaf_lo = to_le32((fblock << 32) >> 32);
+    index->leaf_hi = to_le16((uint16_t)(fblock >> 32));
+}
+
+/**@brief Get magic value from extent header.
+ * @param header Extent header to load value from
+ * @return Magic value of extent header */
+static inline uint16_t
+ext4_extent_header_get_magic(struct ext4_extent_header *header)
+{
+    return to_le16(header->magic);
+}
+
+/**@brief Set magic value to extent header.
+ * @param header Extent header to set value to
+ * @param magic  Magic value of extent header */
+static inline void ext4_extent_header_set_magic(struct ext4_extent_header *header,
+                        uint16_t magic)
+{
+    header->magic = to_le16(magic);
+}
+
+/**@brief Get number of entries from extent header
+ * @param header Extent header to get value from
+ * @return Number of entries covered by extent header */
+static inline uint16_t
+ext4_extent_header_get_entries_count(struct ext4_extent_header *header)
+{
+    return to_le16(header->entries_count);
+}
+
+/**@brief Set number of entries to extent header
+ * @param header Extent header to set value to
+ * @param count  Number of entries covered by extent header */
+static inline void
+ext4_extent_header_set_entries_count(struct ext4_extent_header *header,
+                     uint16_t count)
+{
+    header->entries_count = to_le16(count);
+}
+
+/**@brief Get maximum number of entries from extent header
+ * @param header Extent header to get value from
+ * @return Maximum number of entries covered by extent header */
+static inline uint16_t
+ext4_extent_header_get_max_entries_count(struct ext4_extent_header *header)
+{
+    return to_le16(header->max_entries_count);
+}
+
+/**@brief Set maximum number of entries to extent header
+ * @param header    Extent header to set value to
+ * @param max_count Maximum number of entries covered by extent header */
+static inline void
+ext4_extent_header_set_max_entries_count(struct ext4_extent_header *header,
+                          uint16_t max_count)
+{
+    header->max_entries_count = to_le16(max_count);
+}
+
+/**@brief Get depth of extent subtree.
+ * @param header Extent header to get value from
+ * @return Depth of extent subtree */
+static inline uint16_t
+ext4_extent_header_get_depth(struct ext4_extent_header *header)
+{
+    return to_le16(header->depth);
+}
+
+/**@brief Set depth of extent subtree.
+ * @param header Extent header to set value to
+ * @param depth  Depth of extent subtree */
+static inline void
+ext4_extent_header_set_depth(struct ext4_extent_header *header, uint16_t depth)
+{
+    header->depth = to_le16(depth);
+}
+
+/**@brief Get generation from extent header
+ * @param header Extent header to get value from
+ * @return Generation */
+static inline uint32_t
+ext4_extent_header_get_generation(struct ext4_extent_header *header)
+{
+    return to_le32(header->generation);
+}
+
+/**@brief Set generation to extent header
+ * @param header     Extent header to set value to
+ * @param generation Generation */
+static inline void
+ext4_extent_header_set_generation(struct ext4_extent_header *header,
+                       uint32_t generation)
+{
+    header->generation = to_le32(generation);
+}
+
+void ext4_extent_tree_init(struct ext4_inode_ref *inode_ref)
+{
+    /* Initialize extent root header */
+    struct ext4_extent_header *header =
+            ext4_inode_get_extent_header(inode_ref->inode);
+    ext4_extent_header_set_depth(header, 0);
+    ext4_extent_header_set_entries_count(header, 0);
+    ext4_extent_header_set_generation(header, 0);
+    ext4_extent_header_set_magic(header, EXT4_EXTENT_MAGIC);
+
+    uint16_t max_entries = (EXT4_INODE_BLOCKS * sizeof(uint32_t) -
+            sizeof(struct ext4_extent_header)) /
+                    sizeof(struct ext4_extent);
+
+    ext4_extent_header_set_max_entries_count(header, max_entries);
+    inode_ref->dirty  = true;
+}
+
+
 static struct ext4_extent_tail *
 find_ext4_extent_tail(struct ext4_extent_header *eh)
 {
@@ -144,8 +488,7 @@ static void ext4_idx_store_pblock(struct ext4_extent_index *ix, ext4_fsblk_t pb)
 }
 
 static int ext4_allocate_single_block(struct ext4_inode_ref *inode_ref,
-                                     ext4_fsblk_t goal,
-                                     ext4_fsblk_t *blockp)
+                                     ext4_fsblk_t goal, ext4_fsblk_t *blockp)
 {
        return ext4_balloc_alloc_block(inode_ref, goal, blockp);
 }
@@ -227,7 +570,7 @@ static uint16_t ext4_ext_space_root_idx(struct ext4_inode_ref *inode_ref)
 }
 
 static uint16_t ext4_ext_max_entries(struct ext4_inode_ref *inode_ref,
-                                  uint32_t depth)
+                                    uint32_t depth)
 {
        uint16_t max;
 
@@ -317,20 +660,18 @@ static uint32_t ext4_ext_block_csum(struct ext4_inode_ref *inode_ref,
        if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
                uint32_t ino_index = to_le32(inode_ref->index);
                uint32_t ino_gen =
-                       to_le32(ext4_inode_get_generation(inode_ref->inode));
+                   to_le32(ext4_inode_get_generation(inode_ref->inode));
                /* First calculate crc32 checksum against fs uuid */
-               checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
-                               sizeof(sb->uuid));
+               checksum =
+                   ext4_crc32c(EXT4_CRC32_INIT, sb->uuid, sizeof(sb->uuid));
                /* Then calculate crc32 checksum against inode number
                 * and inode generation */
-               checksum = ext4_crc32c(checksum, &ino_index,
-                                    sizeof(ino_index));
-               checksum = ext4_crc32c(checksum, &ino_gen,
-                                    sizeof(ino_gen));
-               /* Finally calculate crc32 checksum against 
+               checksum = ext4_crc32c(checksum, &ino_index, sizeof(ino_index));
+               checksum = ext4_crc32c(checksum, &ino_gen, sizeof(ino_gen));
+               /* Finally calculate crc32 checksum against
                 * the entire extent block up to the checksum field */
-               checksum = ext4_crc32c(checksum, eh,
-                               EXT4_EXTENT_TAIL_OFFSET(eh));
+               checksum =
+                   ext4_crc32c(checksum, eh, EXT4_EXTENT_TAIL_OFFSET(eh));
        }
        return checksum;
 }
@@ -338,8 +679,9 @@ static uint32_t ext4_ext_block_csum(struct ext4_inode_ref *inode_ref,
 #define ext4_ext_block_csum(...) 0
 #endif
 
-static void ext4_extent_block_csum_set(struct ext4_inode_ref *inode_ref __unused,
-                                      struct ext4_extent_header *eh)
+static void
+ext4_extent_block_csum_set(struct ext4_inode_ref *inode_ref __unused,
+                          struct ext4_extent_header *eh)
 {
        struct ext4_extent_tail *tail;
 
@@ -374,7 +716,7 @@ static void ext4_ext_drop_refs(struct ext4_inode_ref *inode_ref,
                if (path->block.lb_id) {
                        if (ext4_bcache_test_flag(path->block.buf, BC_DIRTY))
                                ext4_extent_block_csum_set(inode_ref,
-                                               path->header);
+                                                          path->header);
 
                        ext4_block_set(inode_ref->fs->bdev, &path->block);
                }
@@ -413,12 +755,12 @@ static int ext4_ext_check(struct ext4_inode_ref *inode_ref,
 
        tail = find_ext4_extent_tail(eh);
        if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
-               if (tail->et_checksum != to_le32(ext4_ext_block_csum(inode_ref, eh))) {
+               if (tail->et_checksum !=
+                   to_le32(ext4_ext_block_csum(inode_ref, eh))) {
                        ext4_dbg(DEBUG_EXTENT,
                                 DBG_WARN "Extent block checksum failed."
-                                "Blocknr: %" PRIu64"\n",
+                                         "Blocknr: %" PRIu64 "\n",
                                 pblk);
-
                }
        }
 
@@ -527,14 +869,14 @@ static int ext4_find_extent(struct ext4_inode_ref *inode_ref, ext4_lblk_t block,
        if (path) {
                ext4_ext_drop_refs(inode_ref, path, 0);
                if (depth > path[0].maxdepth) {
-                       free(path);
+                       ext4_free(path);
                        *orig_path = path = NULL;
                }
        }
        if (!path) {
                int32_t path_depth = depth + 1;
                /* account possible depth increase */
-               path = calloc(1, sizeof(struct ext4_extent_path) *
+               path = ext4_calloc(1, sizeof(struct ext4_extent_path) *
                                     (path_depth + 1));
                if (!path)
                        return ENOMEM;
@@ -590,7 +932,7 @@ static int ext4_find_extent(struct ext4_inode_ref *inode_ref, ext4_lblk_t block,
 
 err:
        ext4_ext_drop_refs(inode_ref, path, 0);
-       free(path);
+       ext4_free(path);
        if (orig_path)
                *orig_path = NULL;
        return ret;
@@ -605,174 +947,43 @@ static void ext4_ext_init_header(struct ext4_inode_ref *inode_ref,
        eh->depth = depth;
 }
 
-/*
- * Be cautious, the buffer_head returned is not yet mark dirtied. */
-static int ext4_ext_split_node(struct ext4_inode_ref *inode_ref,
-                              struct ext4_extent_path *path, int32_t at,
-                              struct ext4_extent *newext,
-                              ext4_fsblk_t *sibling, struct ext4_block *new_bh)
-{
-       int ret;
-       ext4_fsblk_t newblock;
-       struct ext4_block bh = EXT4_BLOCK_ZERO();
-       int32_t depth = ext_depth(inode_ref->inode);
-
-       ext4_assert(sibling);
-
-       /* FIXME: currently we split at the point after the current extent. */
-       newblock = ext4_ext_new_meta_block(inode_ref, path, newext, &ret, 0);
-       if (ret)
-               goto cleanup;
-
-       /*  For write access.# */
-       ret = ext4_trans_block_get_noread(inode_ref->fs->bdev, &bh, newblock);
-       if (ret != EOK)
-               goto cleanup;
-
-       if (at == depth) {
-               /* start copy from next extent */
-               ptrdiff_t m = EXT_MAX_EXTENT(path[at].header) - path[at].extent;
-               struct ext4_extent_header *neh;
-               neh = ext_block_hdr(&bh);
-               ext4_ext_init_header(inode_ref, neh, 0);
-               if (m) {
-                       struct ext4_extent *ex;
-                       ex = EXT_FIRST_EXTENT(neh);
-                       memmove(ex, path[at].extent + 1,
-                               sizeof(struct ext4_extent) * m);
-                       neh->entries_count =
-                           to_le16(to_le16(neh->entries_count) + m);
-                       path[at].header->entries_count = to_le16(
-                           to_le16(path[at].header->entries_count) - m);
-                       ret = ext4_ext_dirty(inode_ref, path + at);
-                       if (ret)
-                               goto cleanup;
-               }
-       } else {
-               ptrdiff_t m = EXT_MAX_INDEX(path[at].header) - path[at].index;
-               struct ext4_extent_header *neh;
-               neh = ext_block_hdr(&bh);
-               ext4_ext_init_header(inode_ref, neh, depth - at);
-               if (m) {
-                       struct ext4_extent_index *ix;
-                       ix = EXT_FIRST_INDEX(neh);
-                       memmove(ix, path[at].index + 1,
-                               sizeof(struct ext4_extent) * m);
-                       neh->entries_count =
-                           to_le16(to_le16(neh->entries_count) + m);
-                       path[at].header->entries_count = to_le16(
-                           to_le16(path[at].header->entries_count) - m);
-                       ret = ext4_ext_dirty(inode_ref, path + at);
-                       if (ret)
-                               goto cleanup;
-               }
-       }
-cleanup:
-       if (ret) {
-               if (bh.lb_id) {
-                       ext4_block_set(inode_ref->fs->bdev, &bh);
-               }
-               if (newblock)
-                       ext4_ext_free_blocks(inode_ref, newblock, 1, 0);
-
-               newblock = 0;
-       }
-       *sibling = newblock;
-       *new_bh = bh;
-       return ret;
-}
-
-static ext4_lblk_t ext4_ext_block_index(struct ext4_extent_header *eh)
-{
-       if (eh->depth)
-               return to_le32(EXT_FIRST_INDEX(eh)->first_block);
-
-       return to_le32(EXT_FIRST_EXTENT(eh)->first_block);
-}
-
-struct ext_split_trans {
-       ext4_fsblk_t ptr;
-       struct ext4_extent_path path;
-       int switch_to;
-};
-
 static int ext4_ext_insert_index(struct ext4_inode_ref *inode_ref,
-                                struct ext4_extent_path *path,
-                                int32_t at,
-                                struct ext4_extent *newext,
+                                struct ext4_extent_path *path, int at,
                                 ext4_lblk_t insert_index,
-                                ext4_fsblk_t insert_block,
-                                struct ext_split_trans *spt,
-                                bool *need_grow)
+                                ext4_fsblk_t insert_block, bool set_to_ix)
 {
        struct ext4_extent_index *ix;
        struct ext4_extent_path *curp = path + at;
-       struct ext4_block bh = EXT4_BLOCK_ZERO();
-       int32_t len;
-       int err;
+       int len, err;
        struct ext4_extent_header *eh;
 
-       *need_grow = false;
-
        if (curp->index && insert_index == to_le32(curp->index->first_block))
                return EIO;
 
        if (to_le16(curp->header->entries_count) ==
-           to_le16(curp->header->max_entries_count)) {
-               if (at) {
-                       struct ext4_extent_header *neh;
-                       err = ext4_ext_split_node(inode_ref, path, at, newext,
-                                                 &spt->ptr, &bh);
-                       if (err != EOK)
-                               goto out;
+           to_le16(curp->header->max_entries_count))
+               return EIO;
 
-                       neh = ext_block_hdr(&bh);
-                       if (insert_index > to_le32(curp->index->first_block)) {
-                               /* Make decision which node should be used to
-                                * insert the index.*/
-                               if (to_le16(neh->entries_count) >
-                                   to_le16(curp->header->entries_count)) {
-                                       eh = curp->header;
-                                       /* insert after */
-                                       ix = EXT_LAST_INDEX(eh) + 1;
-                               } else {
-                                       eh = neh;
-                                       ix = EXT_FIRST_INDEX(eh);
-                               }
-                       } else {
-                               eh = curp->header;
-                               /* insert before */
-                               ix = EXT_LAST_INDEX(eh);
-                       }
-               } else {
-                       err = EOK;
-                       *need_grow = true;
-                       goto out;
-               }
+       eh = curp->header;
+       if (curp->index == NULL) {
+               ix = EXT_FIRST_INDEX(eh);
+               curp->index = ix;
+       } else if (insert_index > to_le32(curp->index->first_block)) {
+               /* insert after */
+               ix = curp->index + 1;
        } else {
-               eh = curp->header;
-               if (curp->index == NULL) {
-                       ix = EXT_FIRST_INDEX(eh);
-                       curp->index = ix;
-               } else if (insert_index > to_le32(curp->index->first_block)) {
-                       /* insert after */
-                       ix = curp->index + 1;
-               } else {
-                       /* insert before */
-                       ix = curp->index;
-               }
+               /* insert before */
+               ix = curp->index;
        }
 
+       if (ix > EXT_MAX_INDEX(eh))
+               return EIO;
+
        len = EXT_LAST_INDEX(eh) - ix + 1;
        ext4_assert(len >= 0);
        if (len > 0)
                memmove(ix + 1, ix, len * sizeof(struct ext4_extent_index));
 
-       if (ix > EXT_MAX_INDEX(eh)) {
-               err = EIO;
-               goto out;
-       }
-
        ix->first_block = to_le32(insert_index);
        ext4_idx_store_pblock(ix, insert_block);
        eh->entries_count = to_le16(to_le16(eh->entries_count) + 1);
@@ -782,48 +993,151 @@ static int ext4_ext_insert_index(struct ext4_inode_ref *inode_ref,
                goto out;
        }
 
-       if (eh == curp->header)
-               err = ext4_ext_dirty(inode_ref, curp);
-       else
-               err = EOK;
+       err = ext4_ext_dirty(inode_ref, curp);
 
 out:
-       if (err != EOK || *need_grow) {
-               if (bh.lb_id)
-                       ext4_block_set(inode_ref->fs->bdev, &bh);
-
-               spt->ptr = 0;
-       } else if (bh.lb_id) {
-               /* If we got a sibling leaf. */
-               ext4_extent_block_csum_set(inode_ref, ext_block_hdr(&bh));
-               ext4_trans_set_block_dirty(bh.buf);
+       if (err == EOK && set_to_ix) {
+               curp->index = ix;
+               curp->p_block = ext4_idx_pblock(ix);
+       }
+       return err;
+}
 
-               spt->path.p_block = ext4_idx_pblock(ix);
-               spt->path.depth = to_le16(eh->depth);
-               spt->path.maxdepth = 0;
-               spt->path.extent = NULL;
-               spt->path.index = ix;
-               spt->path.header = eh;
-               spt->path.block = bh;
+static int ext4_ext_split_node(struct ext4_inode_ref *inode_ref,
+                              struct ext4_extent_path *path, int at,
+                              struct ext4_extent *newext,
+                              struct ext4_extent_path *npath,
+                              bool *ins_right_leaf)
+{
+       int i, npath_at, ret;
+       ext4_lblk_t insert_index;
+       ext4_fsblk_t newblock = 0;
+       int depth = ext_depth(inode_ref->inode);
+       npath_at = depth - at;
 
-               /*
-                * If newext->ee_block can be included into the
-                * right sub-tree.
-                */
-               if (to_le32(newext->first_block) >=
-                   ext4_ext_block_index(ext_block_hdr(&bh)))
-                       spt->switch_to = 1;
-               else {
-                       curp->index = ix;
-                       curp->p_block = ext4_idx_pblock(ix);
+       ext4_assert(at > 0);
+
+       if (path[depth].extent != EXT_MAX_EXTENT(path[depth].header))
+               insert_index = path[depth].extent[1].first_block;
+       else
+               insert_index = newext->first_block;
+
+       for (i = depth; i >= at; i--, npath_at--) {
+               struct ext4_block bh = EXT4_BLOCK_ZERO();
+
+               /* FIXME: currently we split at the point after the current
+                * extent. */
+               newblock =
+                   ext4_ext_new_meta_block(inode_ref, path, newext, &ret, 0);
+               if (ret != EOK)
+                       goto cleanup;
+
+               /*  For write access.*/
+               ret = ext4_trans_block_get_noread(inode_ref->fs->bdev, &bh,
+                                                 newblock);
+               if (ret != EOK)
+                       goto cleanup;
+
+               if (i == depth) {
+                       /* start copy from next extent */
+                       int m = EXT_MAX_EXTENT(path[i].header) - path[i].extent;
+                       struct ext4_extent_header *neh;
+                       struct ext4_extent *ex;
+                       neh = ext_block_hdr(&bh);
+                       ex = EXT_FIRST_EXTENT(neh);
+                       ext4_ext_init_header(inode_ref, neh, 0);
+                       if (m) {
+                               memmove(ex, path[i].extent + 1,
+                                       sizeof(struct ext4_extent) * m);
+                               neh->entries_count =
+                                   to_le16(to_le16(neh->entries_count) + m);
+                               path[i].header->entries_count = to_le16(
+                                   to_le16(path[i].header->entries_count) - m);
+                               ret = ext4_ext_dirty(inode_ref, path + i);
+                               if (ret != EOK)
+                                       goto cleanup;
+
+                               npath[npath_at].p_block = ext4_ext_pblock(ex);
+                               npath[npath_at].extent = ex;
+                       } else {
+                               npath[npath_at].p_block = 0;
+                               npath[npath_at].extent = NULL;
+                       }
+
+                       npath[npath_at].depth = to_le16(neh->depth);
+                       npath[npath_at].maxdepth = 0;
+                       npath[npath_at].index = NULL;
+                       npath[npath_at].header = neh;
+                       npath[npath_at].block = bh;
+
+                       ext4_trans_set_block_dirty(bh.buf);
+               } else {
+                       int m = EXT_MAX_INDEX(path[i].header) - path[i].index;
+                       struct ext4_extent_header *neh;
+                       struct ext4_extent_index *ix;
+                       neh = ext_block_hdr(&bh);
+                       ix = EXT_FIRST_INDEX(neh);
+                       ext4_ext_init_header(inode_ref, neh, depth - i);
+                       ix->first_block = to_le32(insert_index);
+                       ext4_idx_store_pblock(ix,
+                                             npath[npath_at + 1].block.lb_id);
+                       neh->entries_count = to_le16(1);
+                       if (m) {
+                               memmove(ix + 1, path[i].index + 1,
+                                       sizeof(struct ext4_extent) * m);
+                               neh->entries_count =
+                                   to_le16(to_le16(neh->entries_count) + m);
+                               path[i].header->entries_count = to_le16(
+                                   to_le16(path[i].header->entries_count) - m);
+                               ret = ext4_ext_dirty(inode_ref, path + i);
+                               if (ret != EOK)
+                                       goto cleanup;
+                       }
+
+                       npath[npath_at].p_block = ext4_idx_pblock(ix);
+                       npath[npath_at].depth = to_le16(neh->depth);
+                       npath[npath_at].maxdepth = 0;
+                       npath[npath_at].extent = NULL;
+                       npath[npath_at].index = ix;
+                       npath[npath_at].header = neh;
+                       npath[npath_at].block = bh;
+
+                       ext4_trans_set_block_dirty(bh.buf);
                }
+       }
+       newblock = 0;
 
-       } else {
-               spt->ptr = 0;
-               curp->index = ix;
-               curp->p_block = ext4_idx_pblock(ix);
+       /*
+        * If newext->first_block can be included into the
+        * right sub-tree.
+        */
+       if (to_le32(newext->first_block) < insert_index)
+               *ins_right_leaf = false;
+       else
+               *ins_right_leaf = true;
+
+       ret = ext4_ext_insert_index(inode_ref, path, at - 1, insert_index,
+                                   npath[0].block.lb_id, *ins_right_leaf);
+
+cleanup:
+       if (ret != EOK) {
+               if (newblock)
+                       ext4_ext_free_blocks(inode_ref, newblock, 1, 0);
+
+               npath_at = depth - at;
+               while (npath_at >= 0) {
+                       if (npath[npath_at].block.lb_id) {
+                               newblock = npath[npath_at].block.lb_id;
+                               ext4_block_set(inode_ref->fs->bdev,
+                                              &npath[npath_at].block);
+                               ext4_ext_free_blocks(inode_ref, newblock, 1, 0);
+                               memset(&npath[npath_at].block, 0,
+                                      sizeof(struct ext4_block));
+                       }
+                       npath_at--;
+               }
        }
-       return err;
+       return ret;
 }
 
 /*
@@ -877,12 +1191,12 @@ static int ext4_ext_correct_indexes(struct ext4_inode_ref *inode_ref,
        return err;
 }
 
-static bool ext4_ext_can_prepend(struct ext4_extent *ex1,
-                                struct ext4_extent *ex2)
+static inline bool ext4_ext_can_prepend(struct ext4_extent *ex1,
+                                       struct ext4_extent *ex2)
 {
        if (ext4_ext_pblock(ex2) + ext4_ext_get_actual_len(ex2) !=
            ext4_ext_pblock(ex1))
-               return false;
+               return 0;
 
 #ifdef AGGRESSIVE_TEST
        if (ext4_ext_get_actual_len(ex1) + ext4_ext_get_actual_len(ex2) > 4)
@@ -892,25 +1206,25 @@ static bool ext4_ext_can_prepend(struct ext4_extent *ex1,
                if (ext4_ext_get_actual_len(ex1) +
                        ext4_ext_get_actual_len(ex2) >
                    EXT_UNWRITTEN_MAX_LEN)
-                       return false;
+                       return 0;
        } else if (ext4_ext_get_actual_len(ex1) + ext4_ext_get_actual_len(ex2) >
                   EXT_INIT_MAX_LEN)
-               return false;
+               return 0;
 #endif
 
        if (to_le32(ex2->first_block) + ext4_ext_get_actual_len(ex2) !=
            to_le32(ex1->first_block))
-               return false;
+               return 0;
 
-       return true;
+       return 1;
 }
 
-static bool ext4_ext_can_append(struct ext4_extent *ex1,
-                               struct ext4_extent *ex2)
+static inline bool ext4_ext_can_append(struct ext4_extent *ex1,
+                                      struct ext4_extent *ex2)
 {
        if (ext4_ext_pblock(ex1) + ext4_ext_get_actual_len(ex1) !=
            ext4_ext_pblock(ex2))
-               return false;
+               return 0;
 
 #ifdef AGGRESSIVE_TEST
        if (ext4_ext_get_actual_len(ex1) + ext4_ext_get_actual_len(ex2) > 4)
@@ -920,36 +1234,30 @@ static bool ext4_ext_can_append(struct ext4_extent *ex1,
                if (ext4_ext_get_actual_len(ex1) +
                        ext4_ext_get_actual_len(ex2) >
                    EXT_UNWRITTEN_MAX_LEN)
-                       return false;
+                       return 0;
        } else if (ext4_ext_get_actual_len(ex1) + ext4_ext_get_actual_len(ex2) >
                   EXT_INIT_MAX_LEN)
-               return false;
+               return 0;
 #endif
 
        if (to_le32(ex1->first_block) + ext4_ext_get_actual_len(ex1) !=
            to_le32(ex2->first_block))
-               return false;
+               return 0;
 
-       return true;
+       return 1;
 }
 
 static int ext4_ext_insert_leaf(struct ext4_inode_ref *inode_ref,
-                               struct ext4_extent_path *path,
-                               int32_t at,
-                               struct ext4_extent *newext,
-                               struct ext_split_trans *spt,
-                               uint32_t flags,
-                               bool *need_grow)
+                               struct ext4_extent_path *path, int at,
+                               struct ext4_extent *newext, int flags,
+                               bool *need_split)
 {
        struct ext4_extent_path *curp = path + at;
        struct ext4_extent *ex = curp->extent;
-       struct ext4_block bh = EXT4_BLOCK_ZERO();
-       int32_t len;
-       int err = EOK;
-       int unwritten;
-       struct ext4_extent_header *eh = NULL;
+       int len, err, unwritten;
+       struct ext4_extent_header *eh;
 
-       *need_grow = false;
+       *need_split = false;
 
        if (curp->extent &&
            to_le32(newext->first_block) == to_le32(curp->extent->first_block))
@@ -963,6 +1271,7 @@ static int ext4_ext_insert_leaf(struct ext4_inode_ref *inode_ref,
                                    ext4_ext_get_actual_len(newext));
                        if (unwritten)
                                ext4_ext_mark_unwritten(curp->extent);
+
                        err = ext4_ext_dirty(inode_ref, curp);
                        goto out;
                }
@@ -976,6 +1285,7 @@ static int ext4_ext_insert_leaf(struct ext4_inode_ref *inode_ref,
                                    ext4_ext_get_actual_len(newext));
                        if (unwritten)
                                ext4_ext_mark_unwritten(curp->extent);
+
                        err = ext4_ext_dirty(inode_ref, curp);
                        goto out;
                }
@@ -983,35 +1293,9 @@ static int ext4_ext_insert_leaf(struct ext4_inode_ref *inode_ref,
 
        if (to_le16(curp->header->entries_count) ==
            to_le16(curp->header->max_entries_count)) {
-               if (at) {
-                       struct ext4_extent_header *neh;
-                       err = ext4_ext_split_node(inode_ref, path, at, newext,
-                                                 &spt->ptr, &bh);
-                       if (err != EOK)
-                               goto out;
-
-                       neh = ext_block_hdr(&bh);
-                       if (to_le32(newext->first_block) >
-                           to_le32(curp->extent->first_block)) {
-                               if (to_le16(neh->entries_count) >
-                                   to_le16(curp->header->entries_count)) {
-                                       eh = curp->header;
-                                       /* insert after */
-                                       ex = EXT_LAST_EXTENT(eh) + 1;
-                               } else {
-                                       eh = neh;
-                                       ex = EXT_FIRST_EXTENT(eh);
-                               }
-                       } else {
-                               eh = curp->header;
-                               /* insert before */
-                               ex = EXT_LAST_EXTENT(eh);
-                       }
-               } else {
-                       err = EOK;
-                       *need_grow = true;
-                       goto out;
-               }
+               err = EIO;
+               *need_split = true;
+               goto out;
        } else {
                eh = curp->header;
                if (curp->extent == NULL) {
@@ -1047,47 +1331,13 @@ static int ext4_ext_insert_leaf(struct ext4_inode_ref *inode_ref,
                goto out;
        }
 
-       if (eh == curp->header) {
-               err = ext4_ext_correct_indexes(inode_ref, path);
-               if (err != EOK)
-                       goto out;
-               err = ext4_ext_dirty(inode_ref, curp);
-       } else
-               err = EOK;
+       err = ext4_ext_correct_indexes(inode_ref, path);
+       if (err != EOK)
+               goto out;
+       err = ext4_ext_dirty(inode_ref, curp);
 
 out:
-       if (err != EOK || *need_grow) {
-               if (bh.lb_id)
-                       ext4_block_set(inode_ref->fs->bdev, &bh);
-
-               spt->ptr = 0;
-       } else if (bh.lb_id) {
-               /* If we got a sibling leaf. */
-               ext4_extent_block_csum_set(inode_ref, ext_block_hdr(&bh));
-               ext4_trans_set_block_dirty(bh.buf);
-
-               spt->path.p_block = ext4_ext_pblock(ex);
-               spt->path.depth = to_le16(eh->depth);
-               spt->path.maxdepth = 0;
-               spt->path.extent = ex;
-               spt->path.index = NULL;
-               spt->path.header = eh;
-               spt->path.block = bh;
-
-               /*
-                * If newext->ee_block can be included into the
-                * right sub-tree.
-                */
-               if (to_le32(newext->first_block) >=
-                   ext4_ext_block_index(ext_block_hdr(&bh)))
-                       spt->switch_to = 1;
-               else {
-                       curp->extent = ex;
-                       curp->p_block = ext4_ext_pblock(ex);
-               }
-
-       } else {
-               spt->ptr = 0;
+       if (err == EOK) {
                curp->extent = ex;
                curp->p_block = ext4_ext_pblock(ex);
        }
@@ -1167,135 +1417,98 @@ static int ext4_ext_grow_indepth(struct ext4_inode_ref *inode_ref,
        return err;
 }
 
-__unused static void print_path(struct ext4_extent_path *path)
-{
-       int32_t i = path->depth;
-       while (i >= 0) {
-
-               ptrdiff_t a =
-                   (path->extent)
-                       ? (path->extent - EXT_FIRST_EXTENT(path->header))
-                       : 0;
-               ptrdiff_t b =
-                   (path->index)
-                       ? (path->index - EXT_FIRST_INDEX(path->header))
-                       : 0;
-
-               (void)a;
-               (void)b;
-               ext4_dbg(DEBUG_EXTENT,
-                        "depth %" PRId32 ", p_block: %" PRIu64 ","
-                        "p_ext offset: %td, p_idx offset: %td\n",
-                        i, path->p_block, a, b);
-               i--;
-               path++;
-       }
-}
-
-static void ext4_ext_replace_path(struct ext4_inode_ref *inode_ref,
-                                 struct ext4_extent_path *path,
-                                 struct ext_split_trans *spt,
-                                 int32_t level)
+static inline void ext4_ext_replace_path(struct ext4_inode_ref *inode_ref,
+                                        struct ext4_extent_path *path,
+                                        struct ext4_extent_path *newpath,
+                                        int at)
 {
-       int32_t depth = ext_depth(inode_ref->inode);
-       int32_t i = depth - level;
-       ext4_ext_drop_refs(inode_ref, path + i, 1);
-       path[i] = spt[level].path;
+       ext4_ext_drop_refs(inode_ref, path + at, 1);
+       path[at] = *newpath;
+       memset(newpath, 0, sizeof(struct ext4_extent_path));
 }
 
-static int ext4_ext_insert_extent(struct ext4_inode_ref *inode_ref,
-                                 struct ext4_extent_path **ppath,
-                                 struct ext4_extent *newext, uint32_t flags)
+int ext4_ext_insert_extent(struct ext4_inode_ref *inode_ref,
+                          struct ext4_extent_path **ppath,
+                          struct ext4_extent *newext, int flags)
 {
-       int32_t i, depth, level;
-       int ret = EOK;
-       ext4_fsblk_t ptr = 0;
-       bool need_grow = false;
+       int depth, level = 0, ret = 0;
        struct ext4_extent_path *path = *ppath;
-       struct ext_split_trans *spt = NULL;
-       struct ext_split_trans newblock;
-
-       memset(&newblock, 0, sizeof(newblock));
-
-       depth = ext_depth(inode_ref->inode);
-       for (i = depth, level = 0; i >= 0; i--, level++)
-               if (EXT_HAS_FREE_INDEX(path + i))
-                       break;
+       struct ext4_extent_path *npath = NULL;
+       bool ins_right_leaf = false;
+       bool need_split;
 
-       if (level) {
-               spt = calloc(1, sizeof(struct ext_split_trans) * (level));
-               if (!spt) {
-                       ret = ENOMEM;
-                       goto out;
-               }
-       }
-       i = 0;
 again:
        depth = ext_depth(inode_ref->inode);
+       ret = ext4_ext_insert_leaf(inode_ref, path, depth, newext, flags,
+                                  &need_split);
+       if (ret == EIO && need_split == true) {
+               int i;
+               for (i = depth, level = 0; i >= 0; i--, level++)
+                       if (EXT_HAS_FREE_INDEX(path + i))
+                               break;
+
+               /* Do we need to grow the tree? */
+               if (i < 0) {
+                       ret = ext4_ext_grow_indepth(inode_ref, 0);
+                       if (ret != EOK)
+                               goto out;
 
-       do {
-               if (!i) {
-                       ret = ext4_ext_insert_leaf(inode_ref, path, depth - i,
-                                                  newext, &newblock, flags,
-                                                  &need_grow);
-               } else {
-                       ret = ext4_ext_insert_index(
-                           inode_ref, path, depth - i, newext,
-                           ext4_ext_block_index(
-                               ext_block_hdr(&spt[i - 1].path.block)),
-                           spt[i - 1].ptr, &newblock,
-                           &need_grow);
-               }
-               ptr = newblock.ptr;
-
-               if (ret != EOK)
-                       goto out;
+                       ret = ext4_find_extent(
+                           inode_ref, to_le32(newext->first_block), ppath, 0);
+                       if (ret != EOK)
+                               goto out;
 
-               else if (spt && ptr && !ret) {
-                       /* Prepare for the next iteration after splitting. */
-                       spt[i] = newblock;
+                       path = *ppath;
+                       /*
+                        * After growing the tree, there should be free space in
+                        * the only child node of the root.
+                        */
+                       level--;
+                       depth++;
                }
 
-               i++;
-       } while (ptr != 0 && i <= depth);
+               i = depth - (level - 1);
+               /* We split from leaf to the i-th node */
+               if (level > 0) {
+                       npath = ext4_calloc(1, sizeof(struct ext4_extent_path) *
+                                             (level));
+                       if (!npath) {
+                               ret = ENOMEM;
+                               goto out;
+                       }
+                       ret = ext4_ext_split_node(inode_ref, path, i, newext,
+                                                 npath, &ins_right_leaf);
+                       if (ret != EOK)
+                               goto out;
 
-       if (need_grow) {
-               ret = ext4_ext_grow_indepth(inode_ref, 0);
-               if (ret)
-                       goto out;
-               ret = ext4_find_extent(inode_ref, to_le32(newext->first_block),
-                                      ppath, 0);
-               if (ret)
-                       goto out;
-               i = depth;
-               path = *ppath;
+                       while (--level >= 0) {
+                               if (ins_right_leaf)
+                                       ext4_ext_replace_path(inode_ref, path,
+                                                             &npath[level],
+                                                             i + level);
+                               else if (npath[level].block.lb_id)
+                                       ext4_ext_drop_refs(inode_ref,
+                                                          npath + level, 1);
+                       }
+               }
                goto again;
        }
+
 out:
-       if (ret) {
+       if (ret != EOK) {
                if (path)
                        ext4_ext_drop_refs(inode_ref, path, 0);
 
-               while (--level >= 0 && spt) {
-                       if (spt[level].ptr) {
-                               ext4_ext_free_blocks(inode_ref, spt[level].ptr,
-                                                    1, 0);
-                               ext4_ext_drop_refs(inode_ref, &spt[level].path,
-                                                  1);
+               while (--level >= 0 && npath) {
+                       if (npath[level].block.lb_id) {
+                               ext4_fsblk_t block = npath[level].block.lb_id;
+                               ext4_ext_free_blocks(inode_ref, block, 1, 0);
+                               ext4_ext_drop_refs(inode_ref, npath + level, 1);
                        }
                }
-       } else {
-               while (--level >= 0 && spt) {
-                       if (spt[level].switch_to)
-                               ext4_ext_replace_path(inode_ref, path, spt,
-                                                     level);
-                       else if (spt[level].ptr)
-                               ext4_ext_drop_refs(inode_ref, &spt[level].path,
-                                                  1);
-               }
        }
-       if (spt)
-               free(spt);
+       if (npath)
+               ext4_free(npath);
 
        return ret;
 }
@@ -1342,6 +1555,13 @@ static int ext4_ext_remove_idx(struct ext4_inode_ref *inode_ref,
                 to_le32(path[i].index->first_block), leaf, 1);
        ext4_ext_free_blocks(inode_ref, leaf, 1, 0);
 
+       /*
+        * We may need to correct the paths after the first extents/indexes in
+        * a node being modified.
+        *
+        * We do not need to consider whether there's any extents presenting or
+        * not, as garbage will be cleared soon.
+        */
        while (i > 0) {
                if (path[i].index != EXT_FIRST_INDEX(path[i].header))
                        break;
@@ -1380,15 +1600,27 @@ static int ext4_ext_remove_leaf(struct ext4_inode_ref *inode_ref,
                new_start = start = to_le32(ex->first_block);
                len = ext4_ext_get_actual_len(ex);
                newblock = ext4_ext_pblock(ex);
+               /*
+                * The 1st case:
+                *   The position that we start truncation is inside the range of an
+                *   extent. Here we should calculate the new length of that extent and
+                *   may start the removal from the next extent.
+                */
                if (start < from) {
                        len -= from - start;
                        new_len = from - start;
                        start = from;
                        start_ex++;
                } else {
+                       /*
+                        * The second case:
+                        *   The last block to be truncated is inside the range of an
+                        *   extent. We need to calculate the new length and the new
+                        *   start of the extent.
+                        */
                        if (start + len - 1 > to) {
-                               len -= start + len - 1 - to;
                                new_len = start + len - 1 - to;
+                               len -= new_len;
                                new_start = to + 1;
                                newblock += to + 1 - start;
                                ex2 = ex;
@@ -1396,7 +1628,15 @@ static int ext4_ext_remove_leaf(struct ext4_inode_ref *inode_ref,
                }
 
                ext4_ext_remove_blocks(inode_ref, ex, start, start + len - 1);
+               /*
+                * Set the first block of the extent if it is presented.
+                */
                ex->first_block = to_le32(new_start);
+
+               /*
+                * If the new length of the current extent we are working on is
+                * zero, remove it.
+                */
                if (!new_len)
                        new_entries--;
                else {
@@ -1413,17 +1653,30 @@ static int ext4_ext_remove_leaf(struct ext4_inode_ref *inode_ref,
        if (ex2 == NULL)
                ex2 = ex;
 
+       /*
+        * Move any remaining extents to the starting position of the node.
+        */
        if (ex2 <= EXT_LAST_EXTENT(eh))
-               memmove(start_ex, ex2, EXT_LAST_EXTENT(eh) - ex2 + 1);
+               memmove(start_ex, ex2, (EXT_LAST_EXTENT(eh) - ex2 + 1) *
+                                          sizeof(struct ext4_extent));
 
        eh->entries_count = to_le16(new_entries);
        ext4_ext_dirty(inode_ref, path + depth);
-       if (path[depth].extent == EXT_FIRST_EXTENT(eh) && eh->entries_count)
+
+       /*
+        * If the extent pointer is pointed to the first extent of the node, and
+        * there's still extents presenting, we may need to correct the indexes
+        * of the paths.
+        */
+       if (path[depth].extent == EXT_FIRST_EXTENT(eh) && eh->entries_count) {
                err = ext4_ext_correct_indexes(inode_ref, path);
+               if (err != EOK)
+                       return err;
+       }
 
        /* if this leaf is free, then we should
         * remove it from index block above */
-       if (err == EOK && eh->entries_count == 0 && path[depth].block.lb_id)
+       if (eh->entries_count == 0 && path[depth].block.lb_id)
                err = ext4_ext_remove_idx(inode_ref, path, depth - 1);
        else if (depth > 0)
                path[depth - 1].index++;
@@ -1431,6 +1684,9 @@ static int ext4_ext_remove_leaf(struct ext4_inode_ref *inode_ref,
        return err;
 }
 
+/*
+ * Check if there's more to remove at a specific level.
+ */
 static bool ext4_ext_more_to_rm(struct ext4_extent_path *path, ext4_lblk_t to)
 {
        if (!to_le16(path->header->entries_count))
@@ -1446,7 +1702,7 @@ static bool ext4_ext_more_to_rm(struct ext4_extent_path *path, ext4_lblk_t to)
 }
 
 int ext4_extent_remove_space(struct ext4_inode_ref *inode_ref, ext4_lblk_t from,
-                         ext4_lblk_t to)
+                            ext4_lblk_t to)
 {
        struct ext4_extent_path *path = NULL;
        int ret = EOK;
@@ -1454,7 +1710,7 @@ int ext4_extent_remove_space(struct ext4_inode_ref *inode_ref, ext4_lblk_t from,
        int32_t i;
 
        ret = ext4_find_extent(inode_ref, from, &path, 0);
-       if (ret)
+       if (ret != EOK)
                goto out;
 
        if (!path[depth].extent) {
@@ -1463,7 +1719,7 @@ int ext4_extent_remove_space(struct ext4_inode_ref *inode_ref, ext4_lblk_t from,
        }
 
        bool in_range = IN_RANGE(from, to_le32(path[depth].extent->first_block),
-                       ext4_ext_get_actual_len(path[depth].extent));
+                                ext4_ext_get_actual_len(path[depth].extent));
 
        if (!in_range) {
                ret = EOK;
@@ -1473,14 +1729,13 @@ int ext4_extent_remove_space(struct ext4_inode_ref *inode_ref, ext4_lblk_t from,
        /* If we do remove_space inside the range of an extent */
        if ((to_le32(path[depth].extent->first_block) < from) &&
            (to < to_le32(path[depth].extent->first_block) +
-                       ext4_ext_get_actual_len(path[depth].extent) - 1)) {
+                     ext4_ext_get_actual_len(path[depth].extent) - 1)) {
 
                struct ext4_extent *ex = path[depth].extent, newex;
                int unwritten = ext4_ext_is_unwritten(ex);
                ext4_lblk_t ee_block = to_le32(ex->first_block);
                int32_t len = ext4_ext_get_actual_len(ex);
-               ext4_fsblk_t newblock =
-                       to + 1 - ee_block + ext4_ext_pblock(ex);
+               ext4_fsblk_t newblock = to + 1 - ee_block + ext4_ext_pblock(ex);
 
                ex->block_count = to_le16(from - ee_block);
                if (unwritten)
@@ -1518,7 +1773,7 @@ int ext4_extent_remove_space(struct ext4_inode_ref *inode_ref, ext4_lblk_t from,
                                leaf_to = to;
 
                        ext4_ext_remove_leaf(inode_ref, path, leaf_from,
-                                       leaf_to);
+                                            leaf_to);
                        ext4_ext_drop_refs(inode_ref, path + i, 0);
                        i--;
                        continue;
@@ -1531,43 +1786,42 @@ int ext4_extent_remove_space(struct ext4_inode_ref *inode_ref, ext4_lblk_t from,
                        if (path[i + 1].block.lb_id)
                                ext4_ext_drop_refs(inode_ref, path + i + 1, 0);
 
-                       ret = read_extent_tree_block(inode_ref,
-                                       ext4_idx_pblock(path[i].index),
-                                       depth - i - 1, &bh, 0);
-                       if (ret)
+                       ret = read_extent_tree_block(
+                           inode_ref, ext4_idx_pblock(path[i].index),
+                           depth - i - 1, &bh, 0);
+                       if (ret != EOK)
                                goto out;
 
-                       path[i].p_block =
-                                       ext4_idx_pblock(path[i].index);
+                       path[i].p_block = ext4_idx_pblock(path[i].index);
                        path[i + 1].block = bh;
                        path[i + 1].header = ext_block_hdr(&bh);
                        path[i + 1].depth = depth - i - 1;
                        if (i + 1 == depth)
-                               path[i + 1].extent = EXT_FIRST_EXTENT(
-                                       path[i + 1].header);
+                               path[i + 1].extent =
+                                   EXT_FIRST_EXTENT(path[i + 1].header);
                        else
                                path[i + 1].index =
-                                       EXT_FIRST_INDEX(path[i + 1].header);
+                                   EXT_FIRST_INDEX(path[i + 1].header);
 
                        i++;
                } else {
                        if (i > 0) {
+                               /*
+                                * Garbage entries will finally be cleared here.
+                                */
                                if (!eh->entries_count)
-                                       ret = ext4_ext_remove_idx(inode_ref, path,
-                                                       i - 1);
+                                       ret = ext4_ext_remove_idx(inode_ref,
+                                                                 path, i - 1);
                                else
                                        path[i - 1].index++;
-
                        }
 
                        if (i)
                                ext4_block_set(inode_ref->fs->bdev,
-                                               &path[i].block);
-
+                                              &path[i].block);
 
                        i--;
                }
-
        }
 
        /* TODO: flexible tree reduction should be here */
@@ -1584,7 +1838,7 @@ int ext4_extent_remove_space(struct ext4_inode_ref *inode_ref, ext4_lblk_t from,
 
 out:
        ext4_ext_drop_refs(inode_ref, path, 0);
-       free(path);
+       ext4_free(path);
        path = NULL;
        return ret;
 }
@@ -1669,7 +1923,7 @@ static int ext4_ext_convert_to_initialized(struct ext4_inode_ref *inode_ref,
                err = ext4_ext_split_extent_at(inode_ref, ppath, split + blocks,
                                               EXT4_EXT_MARK_UNWRIT1 |
                                                   EXT4_EXT_MARK_UNWRIT2);
-               if (!err) {
+               if (err == EOK) {
                        err = ext4_ext_split_extent_at(inode_ref, ppath, split,
                                                       EXT4_EXT_MARK_UNWRIT1);
                }
@@ -1717,7 +1971,8 @@ static int ext4_ext_zero_unwritten_range(struct ext4_inode_ref *inode_ref,
        uint32_t block_size = ext4_sb_get_block_size(&inode_ref->fs->sb);
        for (i = 0; i < blocks_count; i++) {
                struct ext4_block bh = EXT4_BLOCK_ZERO();
-               err = ext4_trans_block_get_noread(inode_ref->fs->bdev, &bh, block + i);
+               err = ext4_trans_block_get_noread(inode_ref->fs->bdev, &bh,
+                                                 block + i);
                if (err != EOK)
                        break;
 
@@ -1730,9 +1985,34 @@ static int ext4_ext_zero_unwritten_range(struct ext4_inode_ref *inode_ref,
        return err;
 }
 
+__unused static void print_path(struct ext4_extent_path *path)
+{
+       int32_t i = path->depth;
+       while (i >= 0) {
+
+               ptrdiff_t a =
+                   (path->extent)
+                       ? (path->extent - EXT_FIRST_EXTENT(path->header))
+                       : 0;
+               ptrdiff_t b =
+                   (path->index)
+                       ? (path->index - EXT_FIRST_INDEX(path->header))
+                       : 0;
+
+               (void)a;
+               (void)b;
+               ext4_dbg(DEBUG_EXTENT,
+                        "depth %" PRId32 ", p_block: %" PRIu64 ","
+                        "p_ext offset: %td, p_idx offset: %td\n",
+                        i, path->p_block, a, b);
+               i--;
+               path++;
+       }
+}
+
 int ext4_extent_get_blocks(struct ext4_inode_ref *inode_ref, ext4_lblk_t iblock,
-                       uint32_t max_blocks, ext4_fsblk_t *result, bool create,
-                       uint32_t *blocks_count)
+                          uint32_t max_blocks, ext4_fsblk_t *result,
+                          bool create, uint32_t *blocks_count)
 {
        struct ext4_extent_path *path = NULL;
        struct ext4_extent newex, *ex;
@@ -1790,12 +2070,12 @@ int ext4_extent_get_blocks(struct ext4_inode_ref *inode_ref, ext4_lblk_t iblock,
 
                        newblock = iblock - ee_block + ee_start;
                        err = ext4_ext_zero_unwritten_range(inode_ref, newblock,
-                                       zero_range);
+                                                           zero_range);
                        if (err != EOK)
                                goto out2;
 
-                       err = ext4_ext_convert_to_initialized(inode_ref, &path,
-                                       iblock, zero_range);
+                       err = ext4_ext_convert_to_initialized(
+                           inode_ref, &path, iblock, zero_range);
                        if (err != EOK)
                                goto out2;
 
@@ -1852,8 +2132,9 @@ out:
 out2:
        if (path) {
                ext4_ext_drop_refs(inode_ref, path, 0);
-               free(path);
+               ext4_free(path);
        }
 
        return err;
 }
+#endif