ref: e9ca4a2d382afa8efd6fe54c869904ba99ed1d76
dir: /src/ext4_extent.c/
/*
* Copyright (c) 2017 Grzegorz Kostka (kostka.grzegorz@gmail.com)
* Copyright (c) 2017 Kaho Ng (ngkaho1234@gmail.com)
*
* 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_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>
#if CONFIG_EXTENTS_ENABLE
/*
* used by extent splitting.
*/
#define EXT4_EXT_MARK_UNWRIT1 0x02 /* mark first half unwritten */
#define EXT4_EXT_MARK_UNWRIT2 0x04 /* mark second half unwritten */
#define EXT4_EXT_DATA_VALID1 0x08 /* first half contains valid data */
#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)
{
return (struct ext4_extent_tail *)(((char *)eh) +
EXT4_EXTENT_TAIL_OFFSET(eh));
}
static struct ext4_extent_header *ext_inode_hdr(struct ext4_inode *inode)
{
return (struct ext4_extent_header *)inode->blocks;
}
static struct ext4_extent_header *ext_block_hdr(struct ext4_block *block)
{
return (struct ext4_extent_header *)block->data;
}
static uint16_t ext_depth(struct ext4_inode *inode)
{
return to_le16(ext_inode_hdr(inode)->depth);
}
static uint16_t ext4_ext_get_actual_len(struct ext4_extent *ext)
{
return (to_le16(ext->block_count) <= EXT_INIT_MAX_LEN
? to_le16(ext->block_count)
: (to_le16(ext->block_count) - EXT_INIT_MAX_LEN));
}
static void ext4_ext_mark_initialized(struct ext4_extent *ext)
{
ext->block_count = to_le16(ext4_ext_get_actual_len(ext));
}
static void ext4_ext_mark_unwritten(struct ext4_extent *ext)
{
ext->block_count |= to_le16(EXT_INIT_MAX_LEN);
}
static int ext4_ext_is_unwritten(struct ext4_extent *ext)
{
/* Extent with ee_len of 0x8000 is treated as an initialized extent */
return (to_le16(ext->block_count) > EXT_INIT_MAX_LEN);
}
/*
* ext4_ext_pblock:
* combine low and high parts of physical block number into ext4_fsblk_t
*/
static ext4_fsblk_t ext4_ext_pblock(struct ext4_extent *ex)
{
ext4_fsblk_t block;
block = to_le32(ex->start_lo);
block |= ((ext4_fsblk_t)to_le16(ex->start_hi) << 31) << 1;
return block;
}
/*
* ext4_idx_pblock:
* combine low and high parts of a leaf physical block number into ext4_fsblk_t
*/
static ext4_fsblk_t ext4_idx_pblock(struct ext4_extent_index *ix)
{
ext4_fsblk_t block;
block = to_le32(ix->leaf_lo);
block |= ((ext4_fsblk_t)to_le16(ix->leaf_hi) << 31) << 1;
return block;
}
/*
* ext4_ext_store_pblock:
* stores a large physical block number into an extent struct,
* breaking it into parts
*/
static void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb)
{
ex->start_lo = to_le32((uint32_t)(pb & 0xffffffff));
ex->start_hi = to_le16((uint16_t)((pb >> 32)) & 0xffff);
}
/*
* ext4_idx_store_pblock:
* stores a large physical block number into an index struct,
* breaking it into parts
*/
static void ext4_idx_store_pblock(struct ext4_extent_index *ix, ext4_fsblk_t pb)
{
ix->leaf_lo = to_le32((uint32_t)(pb & 0xffffffff));
ix->leaf_hi = to_le16((uint16_t)((pb >> 32)) & 0xffff);
}
static int ext4_allocate_single_block(struct ext4_inode_ref *inode_ref,
ext4_fsblk_t goal, ext4_fsblk_t *blockp)
{
return ext4_balloc_alloc_block(inode_ref, goal, blockp);
}
static ext4_fsblk_t ext4_new_meta_blocks(struct ext4_inode_ref *inode_ref,
ext4_fsblk_t goal,
uint32_t flags __unused,
uint32_t *count, int *errp)
{
ext4_fsblk_t block = 0;
*errp = ext4_allocate_single_block(inode_ref, goal, &block);
if (count)
*count = 1;
return block;
}
static void ext4_ext_free_blocks(struct ext4_inode_ref *inode_ref,
ext4_fsblk_t block, uint32_t count,
uint32_t flags __unused)
{
ext4_balloc_free_blocks(inode_ref, block, count);
}
static uint16_t ext4_ext_space_block(struct ext4_inode_ref *inode_ref)
{
uint16_t size;
uint32_t block_size = ext4_sb_get_block_size(&inode_ref->fs->sb);
size = (block_size - sizeof(struct ext4_extent_header)) /
sizeof(struct ext4_extent);
#ifdef AGGRESSIVE_TEST
if (size > 6)
size = 6;
#endif
return size;
}
static uint16_t ext4_ext_space_block_idx(struct ext4_inode_ref *inode_ref)
{
uint16_t size;
uint32_t block_size = ext4_sb_get_block_size(&inode_ref->fs->sb);
size = (block_size - sizeof(struct ext4_extent_header)) /
sizeof(struct ext4_extent_index);
#ifdef AGGRESSIVE_TEST
if (size > 5)
size = 5;
#endif
return size;
}
static uint16_t ext4_ext_space_root(struct ext4_inode_ref *inode_ref)
{
uint16_t size;
size = sizeof(inode_ref->inode->blocks);
size -= sizeof(struct ext4_extent_header);
size /= sizeof(struct ext4_extent);
#ifdef AGGRESSIVE_TEST
if (size > 3)
size = 3;
#endif
return size;
}
static uint16_t ext4_ext_space_root_idx(struct ext4_inode_ref *inode_ref)
{
uint16_t size;
size = sizeof(inode_ref->inode->blocks);
size -= sizeof(struct ext4_extent_header);
size /= sizeof(struct ext4_extent_index);
#ifdef AGGRESSIVE_TEST
if (size > 4)
size = 4;
#endif
return size;
}
static uint16_t ext4_ext_max_entries(struct ext4_inode_ref *inode_ref,
uint32_t depth)
{
uint16_t max;
if (depth == ext_depth(inode_ref->inode)) {
if (depth == 0)
max = ext4_ext_space_root(inode_ref);
else
max = ext4_ext_space_root_idx(inode_ref);
} else {
if (depth == 0)
max = ext4_ext_space_block(inode_ref);
else
max = ext4_ext_space_block_idx(inode_ref);
}
return max;
}
static ext4_fsblk_t ext4_ext_find_goal(struct ext4_inode_ref *inode_ref,
struct ext4_extent_path *path,
ext4_lblk_t block)
{
if (path) {
uint32_t depth = path->depth;
struct ext4_extent *ex;
/*
* Try to predict block placement assuming that we are
* filling in a file which will eventually be
* non-sparse --- i.e., in the case of libbfd writing
* an ELF object sections out-of-order but in a way
* the eventually results in a contiguous object or
* executable file, or some database extending a table
* space file. However, this is actually somewhat
* non-ideal if we are writing a sparse file such as
* qemu or KVM writing a raw image file that is going
* to stay fairly sparse, since it will end up
* fragmenting the file system's free space. Maybe we
* should have some hueristics or some way to allow
* userspace to pass a hint to file system,
* especially if the latter case turns out to be
* common.
*/
ex = path[depth].extent;
if (ex) {
ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
ext4_lblk_t ext_block = to_le32(ex->first_block);
if (block > ext_block)
return ext_pblk + (block - ext_block);
else
return ext_pblk - (ext_block - block);
}
/* it looks like index is empty;
* try to find starting block from index itself */
if (path[depth].block.lb_id)
return path[depth].block.lb_id;
}
/* OK. use inode's group */
return ext4_fs_inode_to_goal_block(inode_ref);
}
/*
* Allocation for a meta data block
*/
static ext4_fsblk_t ext4_ext_new_meta_block(struct ext4_inode_ref *inode_ref,
struct ext4_extent_path *path,
struct ext4_extent *ex, int *err,
uint32_t flags)
{
ext4_fsblk_t goal, newblock;
goal = ext4_ext_find_goal(inode_ref, path, to_le32(ex->first_block));
newblock = ext4_new_meta_blocks(inode_ref, goal, flags, NULL, err);
return newblock;
}
#if CONFIG_META_CSUM_ENABLE
static uint32_t ext4_ext_block_csum(struct ext4_inode_ref *inode_ref,
struct ext4_extent_header *eh)
{
uint32_t checksum = 0;
struct ext4_sblock *sb = &inode_ref->fs->sb;
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));
/* First calculate crc32 checksum against fs 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
* the entire extent block up to the checksum field */
checksum =
ext4_crc32c(checksum, eh, EXT4_EXTENT_TAIL_OFFSET(eh));
}
return checksum;
}
#else
#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)
{
struct ext4_extent_tail *tail;
tail = find_ext4_extent_tail(eh);
tail->et_checksum = to_le32(ext4_ext_block_csum(inode_ref, eh));
}
static int ext4_ext_dirty(struct ext4_inode_ref *inode_ref,
struct ext4_extent_path *path)
{
if (path->block.lb_id)
ext4_trans_set_block_dirty(path->block.buf);
else
inode_ref->dirty = true;
return EOK;
}
static void ext4_ext_drop_refs(struct ext4_inode_ref *inode_ref,
struct ext4_extent_path *path, bool keep_other)
{
int32_t depth, i;
if (!path)
return;
if (keep_other)
depth = 0;
else
depth = path->depth;
for (i = 0; i <= depth; i++, path++) {
if (path->block.lb_id) {
if (ext4_bcache_test_flag(path->block.buf, BC_DIRTY))
ext4_extent_block_csum_set(inode_ref,
path->header);
ext4_block_set(inode_ref->fs->bdev, &path->block);
}
}
}
/*
* Check that whether the basic information inside the extent header
* is correct or not.
*/
static int ext4_ext_check(struct ext4_inode_ref *inode_ref,
struct ext4_extent_header *eh, uint16_t depth,
ext4_fsblk_t pblk __unused)
{
struct ext4_extent_tail *tail;
struct ext4_sblock *sb = &inode_ref->fs->sb;
const char *error_msg;
(void)error_msg;
if (to_le16(eh->magic) != EXT4_EXTENT_MAGIC) {
error_msg = "invalid magic";
goto corrupted;
}
if (to_le16(eh->depth) != depth) {
error_msg = "unexpected eh_depth";
goto corrupted;
}
if (eh->max_entries_count == 0) {
error_msg = "invalid eh_max";
goto corrupted;
}
if (to_le16(eh->entries_count) > to_le16(eh->max_entries_count)) {
error_msg = "invalid eh_entries";
goto corrupted;
}
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))) {
ext4_dbg(DEBUG_EXTENT,
DBG_WARN "Extent block checksum failed."
"Blocknr: %" PRIu64 "\n",
pblk);
}
}
return EOK;
corrupted:
ext4_dbg(DEBUG_EXTENT, "Bad extents B+ tree block: %s. "
"Blocknr: %" PRId64 "\n",
error_msg, pblk);
return EIO;
}
static int read_extent_tree_block(struct ext4_inode_ref *inode_ref,
ext4_fsblk_t pblk, int32_t depth,
struct ext4_block *bh,
uint32_t flags __unused)
{
int err;
err = ext4_trans_block_get(inode_ref->fs->bdev, bh, pblk);
if (err != EOK)
goto errout;
err = ext4_ext_check(inode_ref, ext_block_hdr(bh), depth, pblk);
if (err != EOK)
goto errout;
return EOK;
errout:
if (bh->lb_id)
ext4_block_set(inode_ref->fs->bdev, bh);
return err;
}
/*
* ext4_ext_binsearch_idx:
* binary search for the closest index of the given block
* the header must be checked before calling this
*/
static void ext4_ext_binsearch_idx(struct ext4_extent_path *path,
ext4_lblk_t block)
{
struct ext4_extent_header *eh = path->header;
struct ext4_extent_index *r, *l, *m;
l = EXT_FIRST_INDEX(eh) + 1;
r = EXT_LAST_INDEX(eh);
while (l <= r) {
m = l + (r - l) / 2;
if (block < to_le32(m->first_block))
r = m - 1;
else
l = m + 1;
}
path->index = l - 1;
}
/*
* ext4_ext_binsearch:
* binary search for closest extent of the given block
* the header must be checked before calling this
*/
static void ext4_ext_binsearch(struct ext4_extent_path *path, ext4_lblk_t block)
{
struct ext4_extent_header *eh = path->header;
struct ext4_extent *r, *l, *m;
if (eh->entries_count == 0) {
/*
* this leaf is empty:
* we get such a leaf in split/add case
*/
return;
}
l = EXT_FIRST_EXTENT(eh) + 1;
r = EXT_LAST_EXTENT(eh);
while (l <= r) {
m = l + (r - l) / 2;
if (block < to_le32(m->first_block))
r = m - 1;
else
l = m + 1;
}
path->extent = l - 1;
}
static int ext4_find_extent(struct ext4_inode_ref *inode_ref, ext4_lblk_t block,
struct ext4_extent_path **orig_path, uint32_t flags)
{
struct ext4_extent_header *eh;
struct ext4_block bh = EXT4_BLOCK_ZERO();
ext4_fsblk_t buf_block = 0;
struct ext4_extent_path *path = *orig_path;
int32_t depth, ppos = 0;
int32_t i;
int ret;
eh = ext_inode_hdr(inode_ref->inode);
depth = ext_depth(inode_ref->inode);
if (path) {
ext4_ext_drop_refs(inode_ref, path, 0);
if (depth > path[0].maxdepth) {
ext4_free(path);
*orig_path = path = NULL;
}
}
if (!path) {
int32_t path_depth = depth + 1;
/* account possible depth increase */
path = ext4_calloc(1, sizeof(struct ext4_extent_path) *
(path_depth + 1));
if (!path)
return ENOMEM;
path[0].maxdepth = path_depth;
}
path[0].header = eh;
path[0].block = bh;
i = depth;
/* walk through the tree */
while (i) {
ext4_ext_binsearch_idx(path + ppos, block);
path[ppos].p_block = ext4_idx_pblock(path[ppos].index);
path[ppos].depth = i;
path[ppos].extent = NULL;
buf_block = path[ppos].p_block;
i--;
ppos++;
if (!path[ppos].block.lb_id ||
path[ppos].block.lb_id != buf_block) {
ret = read_extent_tree_block(inode_ref, buf_block, i,
&bh, flags);
if (ret != EOK) {
goto err;
}
if (ppos > depth) {
ext4_block_set(inode_ref->fs->bdev, &bh);
ret = EIO;
goto err;
}
eh = ext_block_hdr(&bh);
path[ppos].block = bh;
path[ppos].header = eh;
}
}
path[ppos].depth = i;
path[ppos].extent = NULL;
path[ppos].index = NULL;
/* find extent */
ext4_ext_binsearch(path + ppos, block);
/* if not an empty leaf */
if (path[ppos].extent)
path[ppos].p_block = ext4_ext_pblock(path[ppos].extent);
*orig_path = path;
ret = EOK;
return ret;
err:
ext4_ext_drop_refs(inode_ref, path, 0);
ext4_free(path);
if (orig_path)
*orig_path = NULL;
return ret;
}
static void ext4_ext_init_header(struct ext4_inode_ref *inode_ref,
struct ext4_extent_header *eh, int32_t depth)
{
eh->entries_count = 0;
eh->max_entries_count = to_le16(ext4_ext_max_entries(inode_ref, depth));
eh->magic = to_le16(EXT4_EXTENT_MAGIC);
eh->depth = depth;
}
static int ext4_ext_insert_index(struct ext4_inode_ref *inode_ref,
struct ext4_extent_path *path, int at,
ext4_lblk_t insert_index,
ext4_fsblk_t insert_block, bool set_to_ix)
{
struct ext4_extent_index *ix;
struct ext4_extent_path *curp = path + at;
int len, err;
struct ext4_extent_header *eh;
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))
return EIO;
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;
}
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));
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);
if (ix > EXT_LAST_INDEX(eh)) {
err = EIO;
goto out;
}
err = ext4_ext_dirty(inode_ref, curp);
out:
if (err == EOK && set_to_ix) {
curp->index = ix;
curp->p_block = ext4_idx_pblock(ix);
}
return err;
}
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;
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;
/*
* 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 ret;
}
/*
* ext4_ext_correct_indexes:
* if leaf gets modified and modified extent is first in the leaf,
* then we have to correct all indexes above.
*/
static int ext4_ext_correct_indexes(struct ext4_inode_ref *inode_ref,
struct ext4_extent_path *path)
{
struct ext4_extent_header *eh;
int32_t depth = ext_depth(inode_ref->inode);
struct ext4_extent *ex;
uint32_t border;
int32_t k;
int err = EOK;
eh = path[depth].header;
ex = path[depth].extent;
if (ex == NULL || eh == NULL)
return EIO;
if (depth == 0) {
/* there is no tree at all */
return EOK;
}
if (ex != EXT_FIRST_EXTENT(eh)) {
/* we correct tree if first leaf got modified only */
return EOK;
}
k = depth - 1;
border = path[depth].extent->first_block;
path[k].index->first_block = border;
err = ext4_ext_dirty(inode_ref, path + k);
if (err != EOK)
return err;
while (k--) {
/* change all left-side indexes */
if (path[k + 1].index != EXT_FIRST_INDEX(path[k + 1].header))
break;
path[k].index->first_block = border;
err = ext4_ext_dirty(inode_ref, path + k);
if (err != EOK)
break;
}
return err;
}
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 0;
#ifdef AGGRESSIVE_TEST
if (ext4_ext_get_actual_len(ex1) + ext4_ext_get_actual_len(ex2) > 4)
return 0;
#else
if (ext4_ext_is_unwritten(ex1)) {
if (ext4_ext_get_actual_len(ex1) +
ext4_ext_get_actual_len(ex2) >
EXT_UNWRITTEN_MAX_LEN)
return 0;
} else if (ext4_ext_get_actual_len(ex1) + ext4_ext_get_actual_len(ex2) >
EXT_INIT_MAX_LEN)
return 0;
#endif
if (to_le32(ex2->first_block) + ext4_ext_get_actual_len(ex2) !=
to_le32(ex1->first_block))
return 0;
return 1;
}
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 0;
#ifdef AGGRESSIVE_TEST
if (ext4_ext_get_actual_len(ex1) + ext4_ext_get_actual_len(ex2) > 4)
return 0;
#else
if (ext4_ext_is_unwritten(ex1)) {
if (ext4_ext_get_actual_len(ex1) +
ext4_ext_get_actual_len(ex2) >
EXT_UNWRITTEN_MAX_LEN)
return 0;
} else if (ext4_ext_get_actual_len(ex1) + ext4_ext_get_actual_len(ex2) >
EXT_INIT_MAX_LEN)
return 0;
#endif
if (to_le32(ex1->first_block) + ext4_ext_get_actual_len(ex1) !=
to_le32(ex2->first_block))
return 0;
return 1;
}
static int ext4_ext_insert_leaf(struct ext4_inode_ref *inode_ref,
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;
int len, err, unwritten;
struct ext4_extent_header *eh;
*need_split = false;
if (curp->extent &&
to_le32(newext->first_block) == to_le32(curp->extent->first_block))
return EIO;
if (!(flags & EXT4_EXT_NO_COMBINE)) {
if (curp->extent && ext4_ext_can_append(curp->extent, newext)) {
unwritten = ext4_ext_is_unwritten(curp->extent);
curp->extent->block_count =
to_le16(ext4_ext_get_actual_len(curp->extent) +
ext4_ext_get_actual_len(newext));
if (unwritten)
ext4_ext_mark_unwritten(curp->extent);
err = ext4_ext_dirty(inode_ref, curp);
goto out;
}
if (curp->extent &&
ext4_ext_can_prepend(curp->extent, newext)) {
unwritten = ext4_ext_is_unwritten(curp->extent);
curp->extent->first_block = newext->first_block;
curp->extent->block_count =
to_le16(ext4_ext_get_actual_len(curp->extent) +
ext4_ext_get_actual_len(newext));
if (unwritten)
ext4_ext_mark_unwritten(curp->extent);
err = ext4_ext_dirty(inode_ref, curp);
goto out;
}
}
if (to_le16(curp->header->entries_count) ==
to_le16(curp->header->max_entries_count)) {
err = EIO;
*need_split = true;
goto out;
} else {
eh = curp->header;
if (curp->extent == NULL) {
ex = EXT_FIRST_EXTENT(eh);
curp->extent = ex;
} else if (to_le32(newext->first_block) >
to_le32(curp->extent->first_block)) {
/* insert after */
ex = curp->extent + 1;
} else {
/* insert before */
ex = curp->extent;
}
}
len = EXT_LAST_EXTENT(eh) - ex + 1;
ext4_assert(len >= 0);
if (len > 0)
memmove(ex + 1, ex, len * sizeof(struct ext4_extent));
if (ex > EXT_MAX_EXTENT(eh)) {
err = EIO;
goto out;
}
ex->first_block = newext->first_block;
ex->block_count = newext->block_count;
ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
eh->entries_count = to_le16(to_le16(eh->entries_count) + 1);
if (ex > EXT_LAST_EXTENT(eh)) {
err = EIO;
goto out;
}
err = ext4_ext_correct_indexes(inode_ref, path);
if (err != EOK)
goto out;
err = ext4_ext_dirty(inode_ref, curp);
out:
if (err == EOK) {
curp->extent = ex;
curp->p_block = ext4_ext_pblock(ex);
}
return err;
}
/*
* ext4_ext_grow_indepth:
* implements tree growing procedure:
* - allocates new block
* - moves top-level data (index block or leaf) into the new block
* - initializes new top-level, creating index that points to the
* just created block
*/
static int ext4_ext_grow_indepth(struct ext4_inode_ref *inode_ref,
uint32_t flags)
{
struct ext4_extent_header *neh;
struct ext4_block bh = EXT4_BLOCK_ZERO();
ext4_fsblk_t newblock, goal = 0;
int err = EOK;
/* Try to prepend new index to old one */
if (ext_depth(inode_ref->inode))
goal = ext4_idx_pblock(
EXT_FIRST_INDEX(ext_inode_hdr(inode_ref->inode)));
else
goal = ext4_fs_inode_to_goal_block(inode_ref);
newblock = ext4_new_meta_blocks(inode_ref, goal, flags, NULL, &err);
if (newblock == 0)
return err;
/* # */
err = ext4_trans_block_get_noread(inode_ref->fs->bdev, &bh, newblock);
if (err != EOK) {
ext4_ext_free_blocks(inode_ref, newblock, 1, 0);
return err;
}
/* move top-level index/leaf into new block */
memmove(bh.data, inode_ref->inode->blocks,
sizeof(inode_ref->inode->blocks));
/* set size of new block */
neh = ext_block_hdr(&bh);
/* old root could have indexes or leaves
* so calculate e_max right way */
if (ext_depth(inode_ref->inode))
neh->max_entries_count =
to_le16(ext4_ext_space_block_idx(inode_ref));
else
neh->max_entries_count =
to_le16(ext4_ext_space_block(inode_ref));
neh->magic = to_le16(EXT4_EXTENT_MAGIC);
ext4_extent_block_csum_set(inode_ref, neh);
/* Update top-level index: num,max,pointer */
neh = ext_inode_hdr(inode_ref->inode);
neh->entries_count = to_le16(1);
ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
if (neh->depth == 0) {
/* Root extent block becomes index block */
neh->max_entries_count =
to_le16(ext4_ext_space_root_idx(inode_ref));
EXT_FIRST_INDEX(neh)
->first_block = EXT_FIRST_EXTENT(neh)->first_block;
}
neh->depth = to_le16(to_le16(neh->depth) + 1);
ext4_trans_set_block_dirty(bh.buf);
inode_ref->dirty = true;
ext4_block_set(inode_ref->fs->bdev, &bh);
return err;
}
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)
{
ext4_ext_drop_refs(inode_ref, path + at, 1);
path[at] = *newpath;
memset(newpath, 0, sizeof(struct ext4_extent_path));
}
int ext4_ext_insert_extent(struct ext4_inode_ref *inode_ref,
struct ext4_extent_path **ppath,
struct ext4_extent *newext, int flags)
{
int depth, level = 0, ret = 0;
struct ext4_extent_path *path = *ppath;
struct ext4_extent_path *npath = NULL;
bool ins_right_leaf = false;
bool need_split;
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;
ret = ext4_find_extent(
inode_ref, to_le32(newext->first_block), ppath, 0);
if (ret != EOK)
goto out;
path = *ppath;
/*
* After growing the tree, there should be free space in
* the only child node of the root.
*/
level--;
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;
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 != EOK) {
if (path)
ext4_ext_drop_refs(inode_ref, path, 0);
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);
}
}
}
if (npath)
ext4_free(npath);
return ret;
}
static void ext4_ext_remove_blocks(struct ext4_inode_ref *inode_ref,
struct ext4_extent *ex, ext4_lblk_t from,
ext4_lblk_t to)
{
ext4_lblk_t len = to - from + 1;
ext4_lblk_t num;
ext4_fsblk_t start;
num = from - to_le32(ex->first_block);
start = ext4_ext_pblock(ex) + num;
ext4_dbg(DEBUG_EXTENT,
"Freeing %" PRIu32 " at %" PRIu64 ", %" PRIu32 "\n", from,
start, len);
ext4_ext_free_blocks(inode_ref, start, len, 0);
}
static int ext4_ext_remove_idx(struct ext4_inode_ref *inode_ref,
struct ext4_extent_path *path, int32_t depth)
{
int err = EOK;
int32_t i = depth;
ext4_fsblk_t leaf;
/* free index block */
leaf = ext4_idx_pblock(path[i].index);
if (path[i].index != EXT_LAST_INDEX(path[i].header)) {
ptrdiff_t len = EXT_LAST_INDEX(path[i].header) - path[i].index;
memmove(path[i].index, path[i].index + 1,
len * sizeof(struct ext4_extent_index));
}
path[i].header->entries_count =
to_le16(to_le16(path[i].header->entries_count) - 1);
err = ext4_ext_dirty(inode_ref, path + i);
if (err != EOK)
return err;
ext4_dbg(DEBUG_EXTENT, "IDX: Freeing %" PRIu32 " at %" PRIu64 ", %d\n",
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;
path[i - 1].index->first_block = path[i].index->first_block;
err = ext4_ext_dirty(inode_ref, path + i - 1);
if (err != EOK)
break;
i--;
}
return err;
}
static int ext4_ext_remove_leaf(struct ext4_inode_ref *inode_ref,
struct ext4_extent_path *path, ext4_lblk_t from,
ext4_lblk_t to)
{
int32_t depth = ext_depth(inode_ref->inode);
struct ext4_extent *ex = path[depth].extent;
struct ext4_extent *start_ex, *ex2 = NULL;
struct ext4_extent_header *eh = path[depth].header;
int32_t len;
int err = EOK;
uint16_t new_entries;
start_ex = ex;
new_entries = to_le16(eh->entries_count);
while (ex <= EXT_LAST_EXTENT(path[depth].header) &&
to_le32(ex->first_block) <= to) {
int32_t new_len = 0;
int unwritten;
ext4_lblk_t start, new_start;
ext4_fsblk_t newblock;
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) {
new_len = start + len - 1 - to;
len -= new_len;
new_start = to + 1;
newblock += to + 1 - start;
ex2 = ex;
}
}
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 {
unwritten = ext4_ext_is_unwritten(ex);
ex->block_count = to_le16(new_len);
ext4_ext_store_pblock(ex, newblock);
if (unwritten)
ext4_ext_mark_unwritten(ex);
}
ex += 1;
}
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) *
sizeof(struct ext4_extent));
eh->entries_count = to_le16(new_entries);
ext4_ext_dirty(inode_ref, path + depth);
/*
* 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 (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++;
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))
return false;
if (path->index > EXT_LAST_INDEX(path->header))
return false;
if (to_le32(path->index->first_block) > to)
return false;
return true;
}
int ext4_extent_remove_space(struct ext4_inode_ref *inode_ref, ext4_lblk_t from,
ext4_lblk_t to)
{
struct ext4_extent_path *path = NULL;
int ret = EOK;
int32_t depth = ext_depth(inode_ref->inode);
int32_t i;
ret = ext4_find_extent(inode_ref, from, &path, 0);
if (ret != EOK)
goto out;
if (!path[depth].extent) {
ret = EOK;
goto out;
}
bool in_range = IN_RANGE(from, to_le32(path[depth].extent->first_block),
ext4_ext_get_actual_len(path[depth].extent));
if (!in_range) {
ret = EOK;
goto out;
}
/* 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)) {
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);
ex->block_count = to_le16(from - ee_block);
if (unwritten)
ext4_ext_mark_unwritten(ex);
ext4_ext_dirty(inode_ref, path + depth);
newex.first_block = to_le32(to + 1);
newex.block_count = to_le16(ee_block + len - 1 - to);
ext4_ext_store_pblock(&newex, newblock);
if (unwritten)
ext4_ext_mark_unwritten(&newex);
ret = ext4_ext_insert_extent(inode_ref, &path, &newex, 0);
goto out;
}
i = depth;
while (i >= 0) {
if (i == depth) {
struct ext4_extent_header *eh;
struct ext4_extent *first_ex, *last_ex;
ext4_lblk_t leaf_from, leaf_to;
eh = path[i].header;
ext4_assert(to_le16(eh->entries_count) > 0);
first_ex = EXT_FIRST_EXTENT(eh);
last_ex = EXT_LAST_EXTENT(eh);
leaf_from = to_le32(first_ex->first_block);
leaf_to = to_le32(last_ex->first_block) +
ext4_ext_get_actual_len(last_ex) - 1;
if (leaf_from < from)
leaf_from = from;
if (leaf_to > to)
leaf_to = to;
ext4_ext_remove_leaf(inode_ref, path, leaf_from,
leaf_to);
ext4_ext_drop_refs(inode_ref, path + i, 0);
i--;
continue;
}
struct ext4_extent_header *eh;
eh = path[i].header;
if (ext4_ext_more_to_rm(path + i, to)) {
struct ext4_block bh = EXT4_BLOCK_ZERO();
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 != EOK)
goto out;
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);
else
path[i + 1].index =
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);
else
path[i - 1].index++;
}
if (i)
ext4_block_set(inode_ref->fs->bdev,
&path[i].block);
i--;
}
}
/* TODO: flexible tree reduction should be here */
if (path->header->entries_count == 0) {
/*
* truncate to zero freed all the tree,
* so we need to correct eh_depth
*/
ext_inode_hdr(inode_ref->inode)->depth = 0;
ext_inode_hdr(inode_ref->inode)->max_entries_count =
to_le16(ext4_ext_space_root(inode_ref));
ret = ext4_ext_dirty(inode_ref, path);
}
out:
ext4_ext_drop_refs(inode_ref, path, 0);
ext4_free(path);
path = NULL;
return ret;
}
static int ext4_ext_split_extent_at(struct ext4_inode_ref *inode_ref,
struct ext4_extent_path **ppath,
ext4_lblk_t split, uint32_t split_flag)
{
struct ext4_extent *ex, newex;
ext4_fsblk_t newblock;
ext4_lblk_t ee_block;
int32_t ee_len;
int32_t depth = ext_depth(inode_ref->inode);
int err = EOK;
ex = (*ppath)[depth].extent;
ee_block = to_le32(ex->first_block);
ee_len = ext4_ext_get_actual_len(ex);
newblock = split - ee_block + ext4_ext_pblock(ex);
if (split == ee_block) {
/*
* case b: block @split is the block that the extent begins with
* then we just change the state of the extent, and splitting
* is not needed.
*/
if (split_flag & EXT4_EXT_MARK_UNWRIT2)
ext4_ext_mark_unwritten(ex);
else
ext4_ext_mark_initialized(ex);
err = ext4_ext_dirty(inode_ref, *ppath + depth);
goto out;
}
ex->block_count = to_le16(split - ee_block);
if (split_flag & EXT4_EXT_MARK_UNWRIT1)
ext4_ext_mark_unwritten(ex);
err = ext4_ext_dirty(inode_ref, *ppath + depth);
if (err != EOK)
goto out;
newex.first_block = to_le32(split);
newex.block_count = to_le16(ee_len - (split - ee_block));
ext4_ext_store_pblock(&newex, newblock);
if (split_flag & EXT4_EXT_MARK_UNWRIT2)
ext4_ext_mark_unwritten(&newex);
err = ext4_ext_insert_extent(inode_ref, ppath, &newex,
EXT4_EXT_NO_COMBINE);
if (err != EOK)
goto restore_extent_len;
out:
return err;
restore_extent_len:
ex->block_count = to_le16(ee_len);
err = ext4_ext_dirty(inode_ref, *ppath + depth);
return err;
}
static int ext4_ext_convert_to_initialized(struct ext4_inode_ref *inode_ref,
struct ext4_extent_path **ppath,
ext4_lblk_t split, uint32_t blocks)
{
int32_t depth = ext_depth(inode_ref->inode), err = EOK;
struct ext4_extent *ex = (*ppath)[depth].extent;
ext4_assert(to_le32(ex->first_block) <= split);
if (split + blocks ==
to_le32(ex->first_block) + ext4_ext_get_actual_len(ex)) {
/* split and initialize right part */
err = ext4_ext_split_extent_at(inode_ref, ppath, split,
EXT4_EXT_MARK_UNWRIT1);
} else if (to_le32(ex->first_block) == split) {
/* split and initialize left part */
err = ext4_ext_split_extent_at(inode_ref, ppath, split + blocks,
EXT4_EXT_MARK_UNWRIT2);
} else {
/* split 1 extent to 3 and initialize the 2nd */
err = ext4_ext_split_extent_at(inode_ref, ppath, split + blocks,
EXT4_EXT_MARK_UNWRIT1 |
EXT4_EXT_MARK_UNWRIT2);
if (err == EOK) {
err = ext4_ext_split_extent_at(inode_ref, ppath, split,
EXT4_EXT_MARK_UNWRIT1);
}
}
return err;
}
static ext4_lblk_t ext4_ext_next_allocated_block(struct ext4_extent_path *path)
{
int32_t depth;
depth = path->depth;
if (depth == 0 && path->extent == NULL)
return EXT_MAX_BLOCKS;
while (depth >= 0) {
if (depth == path->depth) {
/* leaf */
if (path[depth].extent &&
path[depth].extent !=
EXT_LAST_EXTENT(path[depth].header))
return to_le32(
path[depth].extent[1].first_block);
} else {
/* index */
if (path[depth].index !=
EXT_LAST_INDEX(path[depth].header))
return to_le32(
path[depth].index[1].first_block);
}
depth--;
}
return EXT_MAX_BLOCKS;
}
static int ext4_ext_zero_unwritten_range(struct ext4_inode_ref *inode_ref,
ext4_fsblk_t block,
uint32_t blocks_count)
{
int err = EOK;
uint32_t i;
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);
if (err != EOK)
break;
memset(bh.data, 0, block_size);
ext4_trans_set_block_dirty(bh.buf);
err = ext4_block_set(inode_ref->fs->bdev, &bh);
if (err != EOK)
break;
}
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)
{
struct ext4_extent_path *path = NULL;
struct ext4_extent newex, *ex;
ext4_fsblk_t goal;
int err = EOK;
int32_t depth;
uint32_t allocated = 0;
ext4_lblk_t next;
ext4_fsblk_t newblock;
if (result)
*result = 0;
if (blocks_count)
*blocks_count = 0;
/* find extent for this block */
err = ext4_find_extent(inode_ref, iblock, &path, 0);
if (err != EOK) {
path = NULL;
goto out2;
}
depth = ext_depth(inode_ref->inode);
/*
* consistent leaf must not be empty
* this situations is possible, though, _during_ tree modification
* this is why assert can't be put in ext4_ext_find_extent()
*/
ex = path[depth].extent;
if (ex) {
ext4_lblk_t ee_block = to_le32(ex->first_block);
ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
uint16_t ee_len = ext4_ext_get_actual_len(ex);
/* if found exent covers block, simple return it */
if (IN_RANGE(iblock, ee_block, ee_len)) {
/* number of remain blocks in the extent */
allocated = ee_len - (iblock - ee_block);
if (!ext4_ext_is_unwritten(ex)) {
newblock = iblock - ee_block + ee_start;
goto out;
}
if (!create) {
newblock = 0;
goto out;
}
uint32_t zero_range;
zero_range = allocated;
if (zero_range > max_blocks)
zero_range = max_blocks;
newblock = iblock - ee_block + ee_start;
err = ext4_ext_zero_unwritten_range(inode_ref, newblock,
zero_range);
if (err != EOK)
goto out2;
err = ext4_ext_convert_to_initialized(
inode_ref, &path, iblock, zero_range);
if (err != EOK)
goto out2;
goto out;
}
}
/*
* requested block isn't allocated yet
* we couldn't try to create block if create flag is zero
*/
if (!create) {
goto out2;
}
/* find next allocated block so that we know how many
* blocks we can allocate without ovelapping next extent */
next = ext4_ext_next_allocated_block(path);
allocated = next - iblock;
if (allocated > max_blocks)
allocated = max_blocks;
/* allocate new block */
goal = ext4_ext_find_goal(inode_ref, path, iblock);
newblock = ext4_new_meta_blocks(inode_ref, goal, 0, &allocated, &err);
if (!newblock)
goto out2;
/* try to insert new extent into found leaf and return */
newex.first_block = to_le32(iblock);
ext4_ext_store_pblock(&newex, newblock);
newex.block_count = to_le16(allocated);
err = ext4_ext_insert_extent(inode_ref, &path, &newex, 0);
if (err != EOK) {
/* free data blocks we just allocated */
ext4_ext_free_blocks(inode_ref, ext4_ext_pblock(&newex),
to_le16(newex.block_count), 0);
goto out2;
}
/* previous routine could use block we allocated */
newblock = ext4_ext_pblock(&newex);
out:
if (allocated > max_blocks)
allocated = max_blocks;
if (result)
*result = newblock;
if (blocks_count)
*blocks_count = allocated;
out2:
if (path) {
ext4_ext_drop_refs(inode_ref, path, 0);
ext4_free(path);
}
return err;
}
#endif