2007-03-19 09:35:45

by Aneesh Kumar K.V

[permalink] [raw]
Subject: [RFC] e2fsprogs: Add ext4migrate

This is work in progress

The below patches add ext4migrate utility that helps in migrating
a ext3 block mapped inode to ext4 extent mapped inode. I have split
the patches into two. They don't build individually. The purpose of
splitting the patches into two is to make the review easeir. The
contents of [PATCH 2/2] is derived out of kernel source.

ext4migrate command takes the below syntax
ext4migrate [--display | --migrate ] <image_name> <filename>

The --display option helps in displaying the block map details for an ext3 inode
and extent map details for an ext4 inode. The --migrate option convert a block mapped
ext3 inode to extent mapped ext4 inode.

This needs to be run on an unmounted file system (offline migration).

The extent insert code is derived out of the latest ext4 kernel source. I have tried
to keep the code as close as possible to the kernel sources. This makes sure that any
fixes for the tree building code in kernel should be easily applied to ext4migrate.
The ext3_ext naming convention instead of ext4_ext found in kernel is to
make sure we are in sync with rest of e2fsprogs source.

The inode modification is done only at the last stage. This is to make sure that if we
fail at any intermediate stage, we exit without touching the disk. Another option I am thinking
is to copy the old mapping to a temporary inode. This makes sure that if by any chance the migration
fails partially writing to the disk one can retrieve the file using temporary inode.

The other alternative i am working on right now is to look at the online defragmentation
and see if that can be adapted to achieve online migration.

The patch applies on top of e2fsprogs found at

http://www.kernel.org/pub/linux/kernel/people/tytso/e2fsprogs-interim/e2fsprogs-1.39-tyt1/e2fsprogs-1.39-tyt1.tar.bz2


2007-03-19 09:35:48

by Aneesh Kumar K.V

[permalink] [raw]
Subject: [PATCH 1/2] e2fsprogs: Add ext4migrate

From: Aneesh Kumar K.V <[email protected]>

Add ext4migrate utility that helps in migrating a ext3 block mapped
inode to ext4 extent mapped inode.

ext4migrate command takes the below syntax
ext4migrate [--display | --migrate ] <image_name> <filename>

The --display option helps in displaying the block map details for an ext3 inode
and extent map details for an ext4 inode. The --migrate option convert a block mapped
ext3 inode to extent mapped ext4 inode.

This needs to be run on an unmounted file system (offline migration).

The inode modification is done only at the last stage. This is to make sure that if we
fail at any intermediate stage, we exit without touching the disk. Another option I am thinking
is to copy the old mapping to a temporary inode. This makes sure that if by any chance the migration
fails partially writing to the disk one can retrieve the file using temporary inode.

Signed-off-by: Aneesh Kumar K.V <[email protected]>
---
Makefile.in | 3 +-
configure.in | 21 ++-
ext4migrate/Makefile.in | 66 ++++++
ext4migrate/migrate.c | 568 +++++++++++++++++++++++++++++++++++++++++++++++
ext4migrate/migrate.h | 14 ++
5 files changed, 670 insertions(+), 2 deletions(-)
create mode 100644 ext4migrate/Makefile.in
create mode 100644 ext4migrate/migrate.c
create mode 100644 ext4migrate/migrate.h

diff --git a/Makefile.in b/Makefile.in
index 0d31caa..9d8d291 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -9,9 +9,10 @@ INSTALL = @[email protected]

@[email protected]_DIR= resize
@[email protected]_DIR= debugfs
[email protected][email protected]_DIR= ext4migrate

LIB_SUBDIRS=lib/et lib/ss lib/e2p lib/ext2fs lib/uuid lib/blkid intl
-PROG_SUBDIRS=e2fsck $(DEBUGFS_DIR) misc $(RESIZE_DIR) tests/progs po
+PROG_SUBDIRS=e2fsck $(DEBUGFS_DIR) misc $(RESIZE_DIR) tests/progs po $(EXT4MIGRATE_DIR)
SUBDIRS=util $(LIB_SUBDIRS) $(PROG_SUBDIRS) tests

SUBS= lib/ext2fs/ext2_types.h lib/blkid/blkid_types.h lib/uuid/uuid_types.h
diff --git a/configure.in b/configure.in
index 44b718d..5ae5e0b 100644
--- a/configure.in
+++ b/configure.in
@@ -436,6 +436,24 @@ echo "Building e2fsck statically by default"
)
AC_SUBST(E2FSCK_TYPE)
dnl
+dnl handle --enable-ext4migrate
+dnl
+AC_ARG_ENABLE([ext4migrate],
+[ --disable-ext4migrate disable support of ext4migrate program],
+if test "$enableval" = "no"
+then
+ echo "Disabling ext4migrate support"
+ EXT4MIGRATE_CMT="#"
+else
+ EXT4MIGRATE_CMT=
+ echo "Enabling ext4migrate support"
+fi
+,
+echo "Enabling ext4migrate support by default"
+EXT4MIGRATE_CMT=
+)
+AC_SUBST(EXT4MIGRATE_CMT)
+dnl
dnl See whether to install the `fsck' wrapper program (that calls e2fsck)
dnl
AC_ARG_ENABLE([fsck],
@@ -862,7 +880,8 @@ for i in MCONFIG Makefile e2fsprogs.spec \
lib/e2p/e2p.pc lib/blkid/blkid.pc lib/ext2fs/ext2fs.pc \
misc/Makefile ext2ed/Makefile e2fsck/Makefile \
debugfs/Makefile tests/Makefile tests/progs/Makefile \
- resize/Makefile doc/Makefile intl/Makefile po/Makefile.in ; do
+ resize/Makefile doc/Makefile intl/Makefile po/Makefile.in \
+ ext4migrate/Makefile ; do
if test -d `dirname ${srcdir}/$i` ; then
outlist="$outlist $i"
fi
diff --git a/ext4migrate/Makefile.in b/ext4migrate/Makefile.in
new file mode 100644
index 0000000..05b089e
--- /dev/null
+++ b/ext4migrate/Makefile.in
@@ -0,0 +1,66 @@
+#
+# Standard e2fsprogs prologue....
+#
+
+srcdir = @[email protected]
+top_srcdir = @[email protected]
+VPATH = @[email protected]
+top_builddir = ..
+my_dir = util
+INSTALL = @[email protected]
[email protected]@
+
+SRCS = $(srcdir)/migrate.c
+
+LIBS= $(LIBEXT2FS) $(LIBCOM_ERR)
+DEPLIBS= $(LIBEXT2FS) $(LIBCOM_ERR)
+
+.c.o:
+ @echo " CC $<"
+ @$(CC) -c $(ALL_CFLAGS) $< -o [email protected]
+ @#cc -g -I../lib/ -Wunreachable-code -Wunused -Wunused-function
+ @#-Wunused-label -Wunused-parameter -Wunused-value -Wunused-variable -c migrate.c
+
+PROGS= ext4migrate
+
+all:: $(PROGS)
+
+ext4migrate: migrate.o extents.o $(DEPLIBS)
+ @echo " LD [email protected]"
+ @$(CC) $(ALL_LDFLAGS) -o ext4migrate migrate.o extents.o $(LIBS)
+
+installdirs:
+ @echo " MKINSTALLDIRS $(root_sbindir)"
+ @$(MKINSTALLDIRS) $(DESTDIR)$(root_sbindir)
+
+install: $(PROGS) installdirs
+ @for i in $(PROGS); do \
+ echo " INSTALL $(root_sbindir)/$$i"; \
+ $(INSTALL_PROGRAM) $$i $(DESTDIR)$(root_sbindir)/$$i; \
+ done
+
+install-strip: install
+ @for i in $(PROGS); do \
+ echo " STRIP $(root_sbindir)/$$i"; \
+ $(STRIP) $(DESTDIR)$(root_sbindir)/$$i; \
+ done
+
+uninstall:
+ for i in $(PROGS); do \
+ $(RM) -f $(DESTDIR)$(root_sbindir)/$$i; \
+ done
+clean:
+ $(RM) -f $(PROGS) \#* *.s *.o *.a *~ core
+
+mostlyclean: clean
+
+distclean: clean
+ $(RM) -f .depend Makefile $(srcdir)/TAGS $(srcdir)/Makefile.in.old
+
+# +++ Dependency line eater +++
+#
+# Makefile dependencies follow. This must be the last section in
+# the Makefile.in file
+#
+migrate.o: $(srcdir)/migrate.c
+extents.o: $(srcdir)/extents.c
diff --git a/ext4migrate/migrate.c b/ext4migrate/migrate.c
new file mode 100644
index 0000000..de1d04f
--- /dev/null
+++ b/ext4migrate/migrate.c
@@ -0,0 +1,568 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "migrate.h"
+#include "extents.h"
+
+static struct list_head blk_cache_head;
+static blk_t first_logical_block = 0;
+static blk_t logical_block = 0;
+static ext4_fsblk_t cont_block_start = 0;
+static ext4_fsblk_t prev_block = 0;
+static blk_t i_block[EXT2_N_BLOCKS];
+static int migrate = 0;
+
+static void blk_cache_init(void)
+{
+ INIT_LIST_HEAD(&blk_cache_head);
+
+}
+
+static void inode_i_block_init()
+{
+ struct ext3_extent_header *eh = (struct ext3_extent_header *)i_block;
+ eh->eh_magic = EXT4_EXT_MAGIC;
+ eh->eh_entries = 0;
+ eh->eh_depth = 0;
+ eh->eh_max = ext3_ext_space_root();
+
+}
+
+static void usage(char *prg_name)
+{
+ fprintf(stderr, "%s [--display | --migrate ] <image_name> <filename>\n", prg_name);
+ exit(1);
+}
+
+static void show_extent(struct ext3_extent *ex)
+{
+ ext4_fsblk_t physical_block = ext_pblock(ex);
+
+ printf("logical block start block %u\nNumber of blocks covered %u\n"
+ "Physical block %llu\n", ex->ee_block, ex->ee_len, physical_block);
+}
+static void show_extent_idx(ext2_filsys , struct ext3_extent_idx *);
+static void _get_extent_details(ext2_filsys filesys, struct ext3_extent_header *eh)
+{
+ struct ext3_extent_idx *ix;
+ struct ext3_extent *ex;
+ int i;
+
+ if (eh->eh_depth == 0) {
+ ex = EXT_FIRST_EXTENT(eh);
+ for (i=0; i < eh->eh_entries; i++, ex++) {
+ show_extent(ex);
+ }
+ } else {
+ ix = EXT_FIRST_INDEX(eh);
+ for (i = 0; i < eh->eh_entries; i++, ix++) {
+ show_extent_idx(filesys, ix);
+ }
+
+
+ }
+
+}
+static void show_extent_idx(ext2_filsys filesys, struct ext3_extent_idx *ix)
+{
+ char *block;
+ int retval;
+ ext4_fsblk_t physical_block = idx_pblock(ix);
+
+
+ printf("extent_idx: Physical start block: %llu\n"
+ "Logical Blocks Addressed by this idx is from %d\n",
+ physical_block, ix->ei_block);
+
+ retval = ext2fs_get_mem(filesys->blocksize, &block);
+ if (retval) {
+ com_err("Allocation error", retval, ": Failed to allocate memory");
+ return;
+ }
+
+ retval = ext2fs_read_ext_block(filesys, physical_block, block);
+ if (retval) {
+ com_err("extent", retval,": Unable to read physical block");
+ free(block);
+ return;
+ }
+
+ _get_extent_details(filesys, (struct ext3_extent_header *)block);
+
+ free(block);
+ return;
+
+
+}
+static void get_extent_details(ext2_filsys filesys, struct ext2_inode *file_inode_struct)
+{
+ struct ext3_extent_header *eh;
+
+ eh = (struct ext3_extent_header *)file_inode_struct->i_block;
+ return _get_extent_details(filesys, eh);
+
+}
+static void block_iterate(ext2_filsys filesys, struct ext2_inode *file_inode_struct, ext4_fsblk_t block_num,
+ void (*func)(ext2_filsys filesys, struct ext2_inode *file_inode_struct, ext4_fsblk_t block))
+{
+ int i, retval;
+ blk_t *block;
+ int max_entries = filesys->blocksize/4;
+ retval = ext2fs_get_mem(filesys->blocksize, &block);
+ if (retval) {
+ com_err("Allocation error", retval, ": Failed to allocate memory");
+ return;
+ }
+ retval = ext2fs_read_ext_block(filesys, block_num, block);
+ if (retval) {
+ com_err("block_interate", retval,": Unable to read physical block");
+ free(block);
+ return;
+ }
+ for (i=0; i < max_entries; i++) {
+ if (block[i]) {
+ (*func)(filesys, file_inode_struct, block[i]);
+ }
+ }
+ free(block);
+
+}
+
+/*FIXME!! goal value passed as zero */
+
+/* FIXME!! 48 bit block
+ * Can we ask for block addressed by 48 bit ?
+ * We have actually mounted a ext3 file system via ext4dev If want want
+ * we will have to change the group descriptor also */
+/* Function is also called from extents.c */
+struct blk_cache * get_block(ext2_filsys filesys, ext4_fsblk_t pblock)
+{
+ struct list_head *entry;
+ struct blk_cache *blk;
+ void *addr;
+ int retval;
+ /* need to initialize to fix corruption due to (long) typecasting */
+ ext4_fsblk_t block = 0;
+
+
+ if (pblock == 0) {
+ /* allocate in disk and give back */
+ /* FIXME!! 48 bit block */
+ retval = ext2fs_new_block(filesys, 0, NULL, (blk_t *)&block);
+ if (retval) {
+ /*
+ * In case we fail we don't write/sync previous update
+ * we don't want partial conversion
+ */
+ return NULL;
+ }
+ ext2fs_mark_block_bitmap(filesys->block_map, block);
+ ext2fs_mark_bb_dirty(filesys);
+
+ addr = malloc(filesys->blocksize);
+ if (!addr)
+ return NULL;
+ memset(addr, 0, filesys->blocksize);
+
+ blk = malloc(sizeof(struct blk_cache));
+ if (!blk) {
+ free(addr);
+ return NULL;
+ }
+
+ blk->pblock = (ext4_fsblk_t)block;
+ blk->block_mem_addr = addr;
+ list_add(&(blk->head), &blk_cache_head);
+
+ return blk;
+ }
+
+
+ list_for_each(entry, &blk_cache_head) {
+
+ blk = list_entry(entry, struct blk_cache, head);
+
+ if (blk->pblock == pblock ) {
+ return blk;
+
+ }
+ }
+
+ /*
+ * No block present. Allocate a disk block and a memory equivalent
+ * add the same to the list and return the address
+ */
+
+ /* FIXME!! 48 bit block */
+ retval = ext2fs_new_block(filesys, 0, NULL, (blk_t *)&block);
+ if (retval) {
+ /*
+ * In case we fail we don't write/sync previous update
+ * we don't want partial conversion
+ */
+ return NULL;
+ }
+ ext2fs_mark_block_bitmap(filesys->block_map, block);
+ ext2fs_mark_bb_dirty(filesys);
+
+ addr = malloc(filesys->blocksize);
+ if (!addr)
+ return NULL;
+ memset(addr, 0, filesys->blocksize);
+
+ blk = malloc(sizeof(struct blk_cache));
+ if (!blk) {
+ free(addr);
+ return NULL;
+ }
+
+ blk->pblock = (ext4_fsblk_t)block;
+ blk->block_mem_addr = addr;
+ list_add(&(blk->head), &blk_cache_head);
+
+ return blk;
+
+}
+
+
+static int update_extent(ext2_filsys filesys, struct ext2_inode *file_inode_struct,
+ blk_t logical_blk, ext4_fsblk_t start_blk, ext4_fsblk_t end_blk)
+{
+ static int count = 0;
+ int retval = 0;
+ struct ext4_ext_path *path;
+ struct ext3_extent newext;
+ /* start with a local allocated array without touching the inode */
+ struct ext3_extent_header *eh = (struct ext3_extent_header *)i_block;
+ (void)filesys;
+
+ count++;
+ printf("%d Contiguos block %llu <-> %llu\n", count, start_blk, end_blk);
+
+ /* If ware not intending to migrate just return success */
+ if (!migrate)
+ return 0;
+
+
+ newext.ee_block = logical_blk;
+ newext.ee_len = end_blk - start_blk +1;
+ ext3_ext_store_pblock(&newext, start_blk);
+
+ path = ext3_ext_find_extent(filesys, file_inode_struct, eh, logical_blk, NULL);
+
+ if (!path)
+ return EXT2_ET_BLOCK_ALLOC_FAIL;
+
+ retval = ext3_ext_insert_extent(filesys, file_inode_struct, eh, path, &newext);
+
+ free(path);
+ return retval;
+}
+
+static void show_lblk_mapping(ext2_filsys filesys, struct ext2_inode *file_inode_struct, ext4_fsblk_t block)
+{
+ int retval = 0;
+ (void)filesys;
+
+ if (cont_block_start == 0) {
+ cont_block_start = block;
+ prev_block = block;
+ first_logical_block = logical_block;
+ } else {
+
+ if (prev_block+1 == block) {
+
+ prev_block = block;
+
+ } else {
+ retval = update_extent(filesys, file_inode_struct,
+ first_logical_block, cont_block_start, prev_block);
+ if (retval) {
+ com_err("update_extent", retval, ": Failed to update the extent");
+ /* If we fail to update extent we exit */
+ exit(1);
+ }
+ cont_block_start = block;
+ prev_block = block;
+ first_logical_block = logical_block;
+ }
+ }
+
+ //printf("block number is [%d] -> %llu\n", logical_block, block);
+ logical_block++;
+
+
+ return;
+
+}
+static void dind_blk_iterate(ext2_filsys filesys, struct ext2_inode *file_inode_struct, ext4_fsblk_t block_num)
+{
+ //printf("Indirect mappings %llu\n", block_num);
+ block_iterate(filesys, file_inode_struct, block_num , show_lblk_mapping);
+}
+static void tind_blk_iterate(ext2_filsys filesys, struct ext2_inode *file_inode_struct, ext4_fsblk_t block_num)
+{
+ //printf("Double indirect mappings %llu\n", block_num);
+ block_iterate(filesys, file_inode_struct, block_num , dind_blk_iterate);
+}
+
+static int get_indirect_block_mapping_details(ext2_filsys filesys, struct ext2_inode *file_inode_struct)
+{
+ int i, retval = 0;
+ //printf("Direct mappings\n");
+ for (i = 0; i < EXT2_NDIR_BLOCKS; i++) {
+
+ /* EXT2_NDIR_BLOCKS direct blocks */
+ if (file_inode_struct->i_block[i]) {
+ show_lblk_mapping(filesys, file_inode_struct, file_inode_struct->i_block[i]);
+ }
+
+ }
+ if (file_inode_struct->i_block[EXT2_IND_BLOCK]) {
+
+ /* indirect block */
+ //printf("Indirect mappings %d\n", file_inode_struct->i_block[EXT2_IND_BLOCK]);
+ block_iterate(filesys, file_inode_struct, file_inode_struct->i_block[EXT2_IND_BLOCK] , show_lblk_mapping);
+ }
+ if (file_inode_struct->i_block[EXT2_DIND_BLOCK]) {
+
+ /* double indirect block */
+ //printf("Double indirect mappings %d\n", file_inode_struct->i_block[EXT2_DIND_BLOCK]);
+ block_iterate(filesys, file_inode_struct, file_inode_struct->i_block[EXT2_DIND_BLOCK], dind_blk_iterate);
+
+ }
+ if (file_inode_struct->i_block[EXT2_TIND_BLOCK]) {
+
+ /* triple indirect block */
+ //printf("Triple indirect mappings %d\n", file_inode_struct->i_block[EXT2_TIND_BLOCK]);
+ block_iterate(filesys, file_inode_struct, file_inode_struct->i_block[EXT2_TIND_BLOCK], tind_blk_iterate);
+
+ }
+
+ /* update with the last contiguos block */
+ retval = update_extent(filesys, file_inode_struct, first_logical_block, cont_block_start, prev_block);
+ return retval;
+
+
+}
+
+static int write_extent_block(ext2_filsys filesys, ext4_fsblk_t pblock, void *buf)
+{
+ struct ext3_extent_header *eh = (struct ext3_extent_header *)buf;
+ struct ext3_extent_idx *ix;
+ ext4_fsblk_t tpblock;
+ struct blk_cache *blkc;
+ int i, retval;
+
+ if (eh->eh_depth == 0) {
+ retval = ext2fs_write_ext_block(filesys, pblock, buf);
+ if (retval)
+ goto err_out;
+ } else {
+ ix = EXT_FIRST_INDEX(eh);
+ for (i = 0; i < eh->eh_entries; i++, ix++) {
+
+ tpblock = idx_pblock(ix);
+ blkc = get_block(filesys, tpblock);
+ if (!blkc) {
+ retval = EXT2_ET_BLOCK_ALLOC_FAIL;
+ goto err_out;
+ }
+ retval = write_extent_block(filesys, blkc->pblock, blkc->block_mem_addr);
+ if (retval) {
+ goto err_out;
+ }
+ }
+ }
+
+err_out:
+
+ return retval;
+
+}
+
+static int reset_block_bitmap(ext2_filsys filesys)
+{
+ struct list_head *entry;
+ struct blk_cache *blk;
+ int retval;
+
+ list_for_each(entry, &blk_cache_head) {
+
+ blk = list_entry(entry, struct blk_cache, head);
+
+ ext2fs_unmark_block_bitmap(filesys->block_map, blk->pblock);
+
+ }
+ ext2fs_mark_bb_dirty(filesys);
+ retval = ext2fs_write_block_bitmap(filesys);
+
+ return retval;
+}
+
+static int write_extent_details(ext2_filsys filesys, ext2_ino_t file_ino,
+ struct ext2_inode *file_inode_struct, blk_t *i_block)
+{
+
+ struct ext3_extent_header *eh = (struct ext3_extent_header *)i_block;
+ struct ext3_extent_idx *ix;
+ ext4_fsblk_t pblock;
+ struct blk_cache *blkc;
+ int i, retval;
+
+ /* write the updated block bit map */
+ retval = ext2fs_write_block_bitmap(filesys);
+ if (retval) {
+ return retval;
+ }
+
+ /* Write the blocks to the disk */
+ if (eh->eh_depth != 0) {
+ /* need to write blocks corresponding to extent_idx */
+ ix = EXT_FIRST_INDEX(eh);
+ for (i = 0; i < eh->eh_entries; i++, ix++) {
+
+ pblock = idx_pblock(ix);
+ blkc = get_block(filesys, pblock);
+ if (!blkc) {
+ retval = EXT2_ET_BLOCK_ALLOC_FAIL;
+ goto err_out;
+ }
+ retval = write_extent_block(filesys, blkc->pblock, blkc->block_mem_addr);
+ if (retval) {
+ goto err_out;
+ }
+ }
+ }
+
+ file_inode_struct->i_flags |= EXT4_EXTENTS_FL;
+ memcpy(file_inode_struct->i_block, i_block, sizeof(file_inode_struct->i_block));
+ /* write inode */
+ retval = ext2fs_write_inode(filesys, file_ino, file_inode_struct);
+ if (retval) {
+ goto err_out;
+ }
+
+ if (!(filesys->super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_EXTENTS)) {
+ filesys->super->s_feature_incompat |= EXT3_FEATURE_INCOMPAT_EXTENTS;
+
+ /* FIXME!! should we write super block */
+ ext2fs_mark_super_dirty(filesys);
+ }
+
+ return retval;
+err_out:
+ if (reset_block_bitmap(filesys)) {
+ com_err("reset_block_bitmap", retval, ": Failed to reset the block bitmap");
+ }
+
+ return retval;
+
+}
+
+main(int argc, char *argv[])
+{
+ char *dev_name, *file_name;
+ int flags, superblock = 0;
+ unsigned int block_size = 0;
+ ext2_filsys filesys;
+ ext2_ino_t file_ino;
+ struct ext2_inode file_inode_struct;
+ int retval;
+
+ if (argc < 3 || argc > 4) {
+ usage(argv[0]);
+ }
+
+ blk_cache_init();
+ inode_i_block_init();
+
+ if (argc == 3 ) {
+ dev_name = argv[1];
+ file_name = argv[2];
+ } else {
+ if (strcmp(argv[1], "--migrate") == 0) {
+ migrate = 1;
+ } else if (strcmp(argv[1], "--display") == 0) {
+ migrate = 0;
+ } else {
+ usage(argv[0]);
+ }
+ dev_name = argv[2];
+ file_name = argv[3];
+ }
+
+ if (migrate) {
+ flags = EXT2_FLAG_SOFTSUPP_FEATURES | EXT2_FLAG_RW | EXT2_FLAG_SUPER_ONLY | EXT2_FLAG_MASTER_SB_ONLY;
+ } else {
+ flags = EXT2_FLAG_SOFTSUPP_FEATURES;
+ }
+
+ retval = ext2fs_open(dev_name, flags, superblock,
+ block_size, unix_io_manager, &filesys);
+ if (retval) {
+ com_err(dev_name, retval,": Unable to open the file system");
+ return;
+ }
+
+ retval = ext2fs_read_inode_bitmap(filesys);
+ if (retval) {
+ com_err(dev_name, retval,": Unable to read inode bitmap");
+ goto err_out;
+ }
+ retval = ext2fs_read_block_bitmap(filesys);
+ if (retval) {
+ com_err(dev_name, retval,": Unable to read block bitmap");
+ goto err_out;
+ }
+
+ retval = ext2fs_namei(filesys, EXT2_ROOT_INO,
+ EXT2_ROOT_INO, file_name, &file_ino);
+ if (retval) {
+ com_err(file_name, retval,": Unable to get file inode number");
+ goto err_out;
+ }
+
+ printf("Inode number %d\n", file_ino);
+
+ retval = ext2fs_read_inode(filesys, file_ino, &file_inode_struct);
+ if (retval) {
+ com_err(file_name, retval,": Unable to get file inode number");
+ goto err_out;
+ }
+ if (file_inode_struct.i_flags & EXT4_EXTENTS_FL) {
+ /*
+ * extents support
+ */
+ printf("extent: Support enabled\n");
+ get_extent_details(filesys, &file_inode_struct);
+
+ } else {
+
+ retval = get_indirect_block_mapping_details(filesys, &file_inode_struct);
+
+ if (retval) {
+
+ com_err("get_indirect_block_mapping_details", retval,
+ ": Failed to get the block mapaping details");
+
+ } else if (migrate) {
+
+ /*
+ * Only if we have successfully walked the block mapping write the extent details
+ */
+ retval = write_extent_details(filesys, file_ino, &file_inode_struct, i_block);
+ if (retval) {
+ com_err("write_extent_details", 0, "Failed to write extent details");
+ goto err_out;
+ }
+
+ /* dump the migrated extent details */
+ get_extent_details(filesys, &file_inode_struct);
+ }
+ }
+
+err_out:
+ ext2fs_close(filesys);
+
+}
diff --git a/ext4migrate/migrate.h b/ext4migrate/migrate.h
new file mode 100644
index 0000000..b3f25ac
--- /dev/null
+++ b/ext4migrate/migrate.h
@@ -0,0 +1,14 @@
+
+#include "ext2fs/ext2_fs.h"
+#include "ext2fs/ext2fs.h"
+#include "ext2fs/kernel-list.h"
+
+typedef unsigned long long ext4_fsblk_t;
+
+#define EXT4_EXT_MAGIC 0xf30a
+
+struct blk_cache {
+ struct list_head head;
+ ext4_fsblk_t pblock;
+ void * block_mem_addr;
+};
--
1.5.0.4.402.g8035-dirty

2007-03-19 09:35:51

by Aneesh Kumar K.V

[permalink] [raw]
Subject: [PATCH 2/2] Add extent related functions

From: Aneesh Kumar K.V <[email protected]>

The code is derived out of the latest ext4 kernel source. I
have tried to keep the code as close as possible to the kernel
sources. This makes sure that any fixes for the tree building
code in kernel should be easily applied to ext4migrate. The
ext3_ext naming convention instead of ext4_ext found in kernel is to
make sure we are in sync with rest of e2fsprogs source

Signed-off-by: Aneesh Kumar K.V <[email protected]>
---
ext4migrate/extents.c | 737 +++++++++++++++++++++++++++++++++++++++++++++++++
ext4migrate/extents.h | 10 +
2 files changed, 747 insertions(+), 0 deletions(-)
create mode 100644 ext4migrate/extents.c
create mode 100644 ext4migrate/extents.h

diff --git a/ext4migrate/extents.c b/ext4migrate/extents.c
new file mode 100644
index 0000000..a21b883
--- /dev/null
+++ b/ext4migrate/extents.c
@@ -0,0 +1,737 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "migrate.h"
+#include "extents.h"
+
+struct ext4_ext_path {
+ ext4_fsblk_t p_block;
+ __u16 p_depth;
+ struct ext3_extent *p_ext;
+ struct ext3_extent_idx *p_idx;
+ struct ext3_extent_header *p_hdr;
+};
+
+/*
+ * ext_pblock:
+ * combine low and high parts of physical block number into ext4_fsblk_t
+ */
+ext4_fsblk_t ext_pblock(struct ext3_extent *ex)
+{
+ ext4_fsblk_t block;
+
+ block = ex->ee_start;
+ block |= ((ext4_fsblk_t) ex->ee_start_hi << 31) << 1;
+ return block;
+}
+
+/*
+ * idx_pblock:
+ * combine low and high parts of a leaf physical block number into ext4_fsblk_t
+ */
+ext4_fsblk_t idx_pblock(struct ext3_extent_idx *ix)
+{
+ ext4_fsblk_t block;
+
+ block = ix->ei_leaf;
+ block |= ((ext4_fsblk_t) ix->ei_leaf_hi << 31) << 1;
+ return block;
+}
+
+/*
+ * ext3_ext_store_pblock:
+ * stores a large physical block number into an extent struct,
+ * breaking it into parts
+ */
+void ext3_ext_store_pblock(struct ext3_extent *ex, ext4_fsblk_t pb)
+{
+ ex->ee_start = (unsigned long) (pb & 0xffffffff);
+ ex->ee_start_hi = (unsigned long) ((pb >> 31) >> 1) & 0xffff;
+}
+
+/*
+ * ext3_idx_store_pblock:
+ * stores a large physical block number into an index struct,
+ * breaking it into parts
+ */
+static void ext3_idx_store_pblock(struct ext3_extent_idx *ix, ext4_fsblk_t pb)
+{
+ ix->ei_leaf = (unsigned long) (pb & 0xffffffff);
+ ix->ei_leaf_hi = (unsigned long) ((pb >> 31) >> 1) & 0xffff;
+}
+
+static int ext3_ext_space_block(ext2_filsys filesys)
+{
+ int size;
+
+ size = (filesys->blocksize - sizeof(struct ext3_extent_header))
+ / sizeof(struct ext3_extent);
+ return size;
+}
+
+static int ext3_ext_space_block_idx(ext2_filsys filesys)
+{
+ int size;
+
+ size = (filesys->blocksize - sizeof(struct ext3_extent_header))
+ / sizeof(struct ext3_extent_idx);
+ return size;
+}
+
+int ext3_ext_space_root(void)
+{
+ int size;
+
+ size = EXT2_N_BLOCKS*sizeof(blk_t);
+ size -= sizeof(struct ext3_extent_header);
+ size /= sizeof(struct ext3_extent);
+ return size;
+}
+
+static int ext3_ext_space_root_idx(void)
+{
+ int size;
+
+ size = EXT2_N_BLOCKS*sizeof(blk_t);
+ size -= sizeof(struct ext3_extent_header);
+ size /= sizeof(struct ext3_extent_idx);
+ return size;
+}
+static void ext3_ext_binsearch_idx(struct ext2_inode *file_inode_struct,
+ struct ext4_ext_path *path, blk_t logical_blk)
+{
+ struct ext3_extent_header *eh = path->p_hdr;
+ struct ext3_extent_idx *r, *l, *m;
+ (void) file_inode_struct;
+
+ l = EXT_FIRST_INDEX(eh) + 1;
+ r = EXT_FIRST_INDEX(eh) + eh->eh_entries - 1;
+ while (l <= r) {
+ m = l + (r - l) / 2;
+ if (logical_blk < m->ei_block)
+ r = m - 1;
+ else
+ l = m + 1;
+ }
+ path->p_idx = l - 1;
+}
+
+static void ext3_ext_binsearch(struct ext2_inode *file_inode_struct,
+ struct ext4_ext_path *path, blk_t logical_blk)
+{
+ struct ext3_extent_header *eh = path->p_hdr;
+ struct ext3_extent *r, *l, *m;
+ (void) file_inode_struct;
+
+ if (eh->eh_entries == 0) {
+ /*
+ * this leaf is empty:
+ * we get such a leaf in split/add case
+ */
+ return;
+ }
+
+ l = EXT_FIRST_EXTENT(eh) + 1;
+ r = EXT_FIRST_EXTENT(eh) + eh->eh_entries - 1;
+
+ while (l <= r) {
+ m = l + (r - l) / 2;
+ if (logical_blk < m->ee_block)
+ r = m - 1;
+ else
+ l = m + 1;
+ }
+
+ path->p_ext = l - 1;
+}
+
+/*
+ * ext3_ext_insert_index:
+ * insert new index [@logical;@ptr] into the block at @curp;
+ * check where to insert: before @curp or after @curp
+ */
+static int ext3_ext_insert_index(struct ext4_ext_path *curp,
+ int logical, ext4_fsblk_t ptr)
+{
+ struct ext3_extent_idx *ix;
+ int len, err = 0;
+
+ len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
+ if (logical > curp->p_idx->ei_block) {
+ /* insert after */
+ if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
+ len = (len - 1) * sizeof(struct ext3_extent_idx);
+ len = len < 0 ? 0 : len;
+ memmove(curp->p_idx + 2, curp->p_idx + 1, len);
+ }
+ ix = curp->p_idx + 1;
+ } else {
+ /* insert before */
+ len = len * sizeof(struct ext3_extent_idx);
+ len = len < 0 ? 0 : len;
+ memmove(curp->p_idx + 1, curp->p_idx, len);
+ ix = curp->p_idx;
+ }
+
+ ix->ei_block = logical;
+ ext3_idx_store_pblock(ix, ptr);
+ curp->p_hdr->eh_entries = curp->p_hdr->eh_entries+1;
+
+ return err;
+}
+/*
+ * ext3_ext_split:
+ * inserts new subtree into the path, using free index entry
+ * at depth @at:
+ * - allocates all needed blocks (new leaf and all intermediate index blocks)
+ * - makes decision where to split
+ * - moves remaining extents and index entries (right to the split point)
+ * into the newly allocated blocks
+ * - initializes subtree
+ */
+static int ext3_ext_split(ext2_filsys filesys, struct ext2_inode *file_inode_struct,
+ struct ext3_extent_header *eh, struct ext4_ext_path *path,
+ struct ext3_extent *newext, int at)
+{
+ int depth = eh->eh_depth;
+ struct ext3_extent_header *neh;
+ struct ext3_extent_idx *fidx;
+ struct ext3_extent *ex;
+ struct blk_cache *blkc;
+ int i = at, k, m, a;
+ ext4_fsblk_t newblock, oldblock;
+ int border;
+ ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
+ int err = 0;
+ (void) file_inode_struct;
+
+ /* make decision: where to split? */
+ /* FIXME: now decision is simplest: at current extent */
+
+ /* if current leaf will be split, then we should use
+ * border from split point */
+ if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
+ border = path[depth].p_ext[1].ee_block;
+ } else {
+ border = newext->ee_block;
+ }
+
+ /*
+ * If error occurs, then we break processing
+ * and mark filesystem read-only. index won't
+ * be inserted and tree will be in consistent
+ * state. Next mount will repair buffers too.
+ */
+
+ /*
+ * Get array to track all allocated blocks.
+ * We need this to handle errors and free blocks
+ * upon them.
+ */
+ ablocks = malloc(sizeof(ext4_fsblk_t) * depth);
+ if (!ablocks)
+ return -1;
+
+ memset(ablocks, 0, sizeof(ext4_fsblk_t) * depth);
+
+ /* allocate all needed blocks */
+ for (a = 0; a < depth - at; a++) {
+ blkc = get_block(filesys, 0);
+ if (!blkc) {
+ err = EXT2_ET_BLOCK_ALLOC_FAIL;
+ goto cleanup;
+ }
+ newblock = blkc->pblock;
+ if (newblock == 0)
+ goto cleanup;
+ ablocks[a] = newblock;
+ }
+
+ /* initialize new leaf */
+ newblock = ablocks[--a];
+
+ neh = (struct ext3_extent_header *)(unsigned long)newblock;
+ neh->eh_entries = 0;
+ neh->eh_max = ext3_ext_space_block(filesys);
+ neh->eh_magic = EXT4_EXT_MAGIC;
+ neh->eh_depth = 0;
+ ex = EXT_FIRST_EXTENT(neh);
+
+ /* move remainder of path[depth] to the new leaf */
+ /* start copy from next extent */
+ /* TODO: we could do it by single memmove */
+ m = 0;
+ path[depth].p_ext++;
+ while (path[depth].p_ext <=
+ EXT_MAX_EXTENT(path[depth].p_hdr)) {
+ /*memmove(ex++, path[depth].p_ext++,
+ sizeof(struct ext4_extent));
+ neh->eh_entries++;*/
+ path[depth].p_ext++;
+ m++;
+ }
+
+ /*
+ * move the part of the old extent to the new allocated one
+ */
+ if (m) {
+ memmove(ex, path[depth].p_ext-m, sizeof(struct ext3_extent)*m);
+ neh->eh_entries = neh->eh_entries+m;
+ }
+
+ /* correct old leaf */
+ if (m) {
+ path[depth].p_hdr->eh_entries = path[depth].p_hdr->eh_entries-m;
+
+ }
+
+ /* create intermediate indexes */
+ k = depth - at - 1;
+
+ /*create intermediate indices */
+ /* insert new index into current index block */
+ /* current depth stored in i var */
+ i = depth - 1;
+ while (k--) {
+ oldblock = newblock;
+ newblock = ablocks[--a];
+
+ neh = (struct ext3_extent_header *)(unsigned long)newblock;
+ neh->eh_entries = 1;
+ neh->eh_magic = EXT4_EXT_MAGIC;
+ neh->eh_max = ext3_ext_space_block_idx(filesys);
+ neh->eh_depth = depth - i;
+ fidx = EXT_FIRST_INDEX(neh);
+ fidx->ei_block = border;
+ ext3_idx_store_pblock(fidx, oldblock);
+
+ /* copy indexes */
+ m = 0;
+ path[i].p_idx++;
+
+ while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) {
+ /*memmove(++fidx, path[i].p_idx++,
+ sizeof(struct ext4_extent_idx));
+ neh->eh_entries++;
+ BUG_ON(neh->eh_entries > neh->eh_max);*/
+ path[i].p_idx++;
+ m++;
+ }
+ if (m) {
+ memmove(++fidx, path[i].p_idx - m,
+ sizeof(struct ext3_extent_idx) * m);
+ neh->eh_entries = neh->eh_entries + m;
+ }
+
+
+ /* correct old index */
+ if (m) {
+ path[i].p_hdr->eh_entries = path[i].p_hdr->eh_entries-m;
+ }
+
+ i--;
+ }
+
+ /* insert new index */
+ err = ext3_ext_insert_index(path + at, border, newblock);
+
+cleanup:
+
+ free(ablocks);
+
+ return err;
+}
+
+/*
+ * ext3_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 ext3_ext_grow_indepth(ext2_filsys filesys, struct ext2_inode *file_inode_struct,
+ struct ext3_extent_header *eh, struct ext4_ext_path *path)
+{
+ struct ext4_ext_path *curp = path;
+ struct ext3_extent_header *neh;
+ struct blk_cache *blkc;
+ ext4_fsblk_t newblock;
+ void *addr;
+
+ blkc = get_block(filesys, 0);
+ if (!blkc) {
+ return EXT2_ET_BLOCK_ALLOC_FAIL;
+
+ }
+ addr = blkc->block_mem_addr;
+ newblock = blkc->pblock;
+
+ /* move top-level index/leaf into new block */
+ memmove(addr, curp->p_hdr, sizeof(file_inode_struct->i_block));
+
+ /* set size of new block */
+ neh = (struct ext3_extent_header *)addr;
+ /* old root could have indexes or leaves
+ * so calculate e_max right way */
+ if (eh->eh_depth) {
+ neh->eh_max = ext3_ext_space_block_idx(filesys);
+ } else {
+ neh->eh_max = ext3_ext_space_block(filesys);
+ }
+
+ neh->eh_magic = EXT4_EXT_MAGIC;
+
+ /* create index in new top-level index: num,max,pointer */
+
+ curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
+ curp->p_hdr->eh_max = ext3_ext_space_root_idx();
+ curp->p_hdr->eh_entries = 1;
+ curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
+ /* FIXME: it works, but actually path[0] can be index */
+ curp->p_idx->ei_block = EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
+ ext3_idx_store_pblock(curp->p_idx, newblock);
+
+ neh = eh;
+ //fidx = EXT_FIRST_INDEX(neh);
+
+ neh->eh_depth = path->p_depth + 1;
+
+ return 0;
+}
+struct ext4_ext_path * ext3_ext_find_extent(ext2_filsys filesys, struct ext2_inode *file_inode_struct,
+ struct ext3_extent_header *eh, blk_t logical_blk, struct ext4_ext_path *path)
+{
+
+ struct blk_cache *blkc;
+ short int depth, i, ppos = 0;
+ int alloc = 0;
+
+ i = depth = eh->eh_depth;
+
+ if (!path) {
+ /*
+ * We may be called to rebuild the path while growing the
+ * depth of the tree
+ */
+ path = malloc(sizeof(struct ext4_ext_path)* (depth+2));
+ if (!path)
+ return NULL;
+
+ alloc = 1;
+ memset(path, 0, sizeof(struct ext4_ext_path)* (depth+2));
+ }
+
+
+ path[0].p_hdr = eh;
+
+ while (i) {
+
+ ext3_ext_binsearch_idx(file_inode_struct, path, logical_blk);
+
+ path[ppos].p_block = idx_pblock(path[ppos].p_idx);
+ path[ppos].p_depth = i;
+ path[ppos].p_ext = NULL;
+
+ blkc = get_block(filesys, path[ppos].p_block);
+
+ if (!blkc) {
+ if (alloc)
+ free(path);
+ return NULL;
+ }
+
+ eh = blkc->block_mem_addr;
+ if (!eh) {
+ if (alloc)
+ free(path);
+ return NULL;
+ }
+ if (eh->eh_max == 0) {
+ if (alloc)
+ free(path);
+ return NULL;
+ }
+ ppos++;
+ path[ppos].p_hdr = eh;
+ i--;
+ }
+ path[ppos].p_depth = i;
+ path[ppos].p_hdr = eh;
+ path[ppos].p_ext = NULL;
+ path[ppos].p_idx = NULL;
+
+ ext3_ext_binsearch(file_inode_struct, path + ppos, logical_blk);
+
+ return path;
+}
+
+static int ext3_ext_create_new_leaf(ext2_filsys filesys, struct ext2_inode *file_inode_struct,
+ struct ext3_extent_header *eh,
+ struct ext4_ext_path *path, struct ext3_extent *newext)
+{
+
+ struct ext4_ext_path *curp;
+ int depth, i, err = 0;
+
+repeat:
+ i = depth = eh->eh_depth;
+
+ /* walk up to the tree and look for free index entry */
+ curp = path + depth;
+ while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
+ i--;
+ curp--;
+ }
+
+ if (EXT_HAS_FREE_INDEX(curp)) {
+
+ /* if we found index with free entry, then use that
+ * entry: create all needed subtree and add new leaf */
+ err = ext3_ext_split(filesys, file_inode_struct, eh, path, newext, i);
+ if (err)
+ goto err_out;
+
+ /* recalculate the path since grow inode would have changed it */
+ path = ext3_ext_find_extent(filesys, file_inode_struct, eh, newext->ee_block, path);
+ if (!path) {
+ err = EXT2_ET_BLOCK_ALLOC_FAIL;
+ goto err_out;
+ }
+
+ } else {
+
+ /* tree is full, time to grow in depth */
+ err = ext3_ext_grow_indepth(filesys, file_inode_struct, eh, path);
+ if (err)
+ goto err_out;
+
+ /* recalculate the path since grow inode would have changed it */
+ path = ext3_ext_find_extent(filesys, file_inode_struct, eh, newext->ee_block, path);
+ if (!path) {
+ err = EXT2_ET_BLOCK_ALLOC_FAIL;
+ goto err_out;
+ }
+
+
+ /*
+ * only first (depth 0 -> 1) produces free space;
+ * in all other cases we have to split the grown tree
+ */
+ depth = eh->eh_depth;
+ if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
+ /* now we need to split */
+ goto repeat;
+ }
+
+ }
+
+err_out:
+
+ return err;
+}
+
+static int ext3_can_extents_be_merged(struct ext3_extent *ex1, struct ext3_extent *ex2)
+{
+ if (ex1->ee_block + ex1->ee_len != ex2->ee_block)
+ return 0;
+
+
+ if (ext_pblock(ex1) + ex1->ee_len == ext_pblock(ex2))
+ return 1;
+ return 0;
+}
+
+
+/*
+ * ext3_ext_next_leaf_block:
+ * returns first allocated block from next leaf or EXT_MAX_BLOCK
+ */
+static unsigned ext3_ext_next_leaf_block(struct ext4_ext_path *path)
+{
+ int depth;
+
+ depth = path->p_depth;
+
+ /* zero-tree has no leaf blocks at all */
+ if (depth == 0)
+ return EXT_MAX_BLOCK;
+
+ /* go to index block */
+ depth--;
+
+ while (depth >= 0) {
+ if (path[depth].p_idx != EXT_LAST_INDEX(path[depth].p_hdr)) {
+ return path[depth].p_idx[1].ei_block;
+ }
+ depth--;
+ }
+
+ return EXT_MAX_BLOCK;
+}
+
+/*
+ * ext3_ext_correct_indexes:
+ * if leaf gets modified and modified extent is first in the leaf,
+ * then we have to correct all indexes above.
+ * TODO: do we need to correct tree in all cases?
+ */
+static void ext3_ext_correct_indexes(struct ext2_inode *file_inode_struct,
+ struct ext3_extent_header *eh, struct ext4_ext_path *path)
+{
+ int depth = eh->eh_depth;
+ struct ext3_extent *ex;
+ int border;
+ int k;
+
+ (void) file_inode_struct;
+
+ eh = path[depth].p_hdr;
+ ex = path[depth].p_ext;
+
+ if (depth == 0) {
+ /* there is no tree at all */
+ return;
+ }
+
+ if (ex != EXT_FIRST_EXTENT(eh)) {
+ /* we correct tree if first leaf got modified only */
+ return;
+ }
+
+ /*
+ * TODO: we need correction if border is smaller than current one
+ */
+ k = depth - 1;
+ border = path[depth].p_ext->ee_block;
+ path[k].p_idx->ei_block = border;
+
+ while (k--) {
+ /* change all left-side indexes */
+ if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
+ break;
+ path[k].p_idx->ei_block = border;
+ }
+
+ return;
+}
+
+int ext3_ext_insert_extent(ext2_filsys filesys, struct ext2_inode *file_inode_struct, struct ext3_extent_header *eh,
+ struct ext4_ext_path *path, struct ext3_extent *newext)
+{
+
+ struct ext3_extent *ex, *fex;
+ struct ext3_extent *nearex; /* nearest extent */
+ struct ext4_ext_path *npath = NULL;
+ int depth, len, err = 0, next;
+ struct ext3_extent_header *save_eh = eh;
+
+ depth = eh->eh_depth;
+ ex = path[depth].p_ext;
+
+ /* try to insert block into found extent and return */
+ if (ex && ext3_can_extents_be_merged(ex, newext)) {
+ ex->ee_len = ex->ee_len + newext->ee_len;
+ eh = path[depth].p_hdr;
+ nearex = ex;
+ goto merge;
+ }
+
+repeat:
+ /* recalculate depth here */
+ depth=save_eh->eh_depth;
+
+ eh = path[depth].p_hdr;
+ if (eh->eh_entries < eh->eh_max)
+ goto has_space;
+
+ /* probably next leaf has space for us? */
+ fex = EXT_LAST_EXTENT(eh);
+ next = ext3_ext_next_leaf_block(path);
+
+ if (newext->ee_block > fex->ee_block && next != EXT_MAX_BLOCK) {
+
+ npath = ext3_ext_find_extent(filesys, file_inode_struct, save_eh, next, NULL);
+ if (!npath) {
+ return EXT2_ET_BLOCK_ALLOC_FAIL;
+ }
+
+ eh = npath[depth].p_hdr;
+ if (eh->eh_entries < eh->eh_max) {
+ path = npath;
+ goto repeat;
+ }
+ }
+
+ /*
+ * There is no free space in the found leaf.
+ * We're gonna add a new leaf in the tree.
+ */
+ err = ext3_ext_create_new_leaf(filesys, file_inode_struct, save_eh, path, newext);
+ if (err)
+ goto cleanup;
+
+ /* recalculate depth here */
+ depth=save_eh->eh_depth;
+ eh = path[depth].p_hdr;
+
+has_space:
+
+ nearex = path[depth].p_ext;
+
+ if (!nearex) {
+ /* there is no extent in this leaf, create first one */
+ path[depth].p_ext = EXT_FIRST_EXTENT(eh);
+
+ } else if (newext->ee_block > nearex->ee_block) {
+
+ if (nearex != EXT_LAST_EXTENT(eh)) {
+ len = EXT_MAX_EXTENT(eh) - nearex;
+ len = (len - 1) * sizeof(struct ext3_extent);
+ len = len < 0 ? 0 : len;
+ memmove(nearex + 2, nearex + 1, len);
+ }
+ path[depth].p_ext = nearex + 1;
+ } else {
+ len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext3_extent);
+ len = len < 0 ? 0 : len;
+ memmove(nearex + 1, nearex, len);
+ path[depth].p_ext = nearex;
+ }
+
+ eh->eh_entries = eh->eh_entries+1;
+ nearex = path[depth].p_ext;
+ nearex->ee_block = newext->ee_block;
+ nearex->ee_start = newext->ee_start;
+ nearex->ee_start_hi = newext->ee_start_hi;
+ nearex->ee_len = newext->ee_len;
+
+merge:
+ /* try to merge extents to the right */
+ while (nearex < EXT_LAST_EXTENT(eh)) {
+ if (!ext3_can_extents_be_merged(nearex, nearex + 1))
+ break;
+ /* merge with next extent! */
+ nearex->ee_len = nearex->ee_len + nearex[1].ee_len;
+
+ if (nearex + 1 < EXT_LAST_EXTENT(eh)) {
+ len = (EXT_LAST_EXTENT(eh) - nearex - 1)
+ * sizeof(struct ext3_extent);
+ memmove(nearex + 1, nearex + 2, len);
+ }
+ eh->eh_entries = eh->eh_entries-1;
+ }
+
+ /* try to merge extents to the left */
+
+ /* time to correct all indexes above */
+ ext3_ext_correct_indexes(file_inode_struct, save_eh, path);
+
+cleanup:
+ if (npath) {
+ free(npath);
+ }
+
+ return err;
+}
+
diff --git a/ext4migrate/extents.h b/ext4migrate/extents.h
new file mode 100644
index 0000000..1cde4f6
--- /dev/null
+++ b/ext4migrate/extents.h
@@ -0,0 +1,10 @@
+
+struct ext4_ext_path * ext3_ext_find_extent(ext2_filsys, struct ext2_inode *,
+ struct ext3_extent_header *, blk_t , struct ext4_ext_path *);
+struct blk_cache * get_block(ext2_filsys, ext4_fsblk_t);
+int ext3_ext_space_root(void);
+ext4_fsblk_t ext_pblock(struct ext3_extent *);
+ext4_fsblk_t idx_pblock(struct ext3_extent_idx *);
+void ext3_ext_store_pblock(struct ext3_extent *, ext4_fsblk_t );
+int ext3_ext_insert_extent(ext2_filsys, struct ext2_inode *, struct ext3_extent_header *,
+ struct ext4_ext_path *, struct ext3_extent *);
--
1.5.0.4.402.g8035-dirty