Hi Ted,
Following patch implement the Undo I/O manager and undoe2fs.
The patches are on top of latest git(23edf9b4674ced1cdf8625bd609d95dbd62923b3)
-aneesh
From: Aneesh Kumar K.V <[email protected]>
This I/O manager saves the contents of the location being overwritten
to a tdb database. This helps in undoing the changes done to the
file system.
The call sequence involve
set_undo_io_backing_manager(unix_io_manager);
set_undo_io_backup_file("/tmp/test.tdb");
retval = ext2fs_open2(dev_name, 0, flags,
superblock, block_size, undo_io_manager,
¤t_fs);
Signed-off-by: Aneesh Kumar K.V <[email protected]>
---
lib/ext2fs/Makefile.in | 7 +-
lib/ext2fs/ext2_io.h | 5 +
lib/ext2fs/undo_io.c | 486 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 496 insertions(+), 2 deletions(-)
create mode 100644 lib/ext2fs/undo_io.c
diff --git a/lib/ext2fs/Makefile.in b/lib/ext2fs/Makefile.in
index 199164a..8644565 100644
--- a/lib/ext2fs/Makefile.in
+++ b/lib/ext2fs/Makefile.in
@@ -66,7 +66,8 @@ OBJS= $(DEBUGFS_LIB_OBJS) $(RESIZE_LIB_OBJS) $(E2IMAGE_LIB_OBJS) \
unix_io.o \
unlink.o \
valid_blk.o \
- version.o
+ version.o \
+ undo_io.o
SRCS= ext2_err.c \
$(srcdir)/alloc.c \
@@ -134,7 +135,8 @@ SRCS= ext2_err.c \
$(srcdir)/tst_bitops.c \
$(srcdir)/tst_byteswap.c \
$(srcdir)/tst_getsize.c \
- $(srcdir)/tst_iscan.c
+ $(srcdir)/tst_iscan.c \
+ $(srcdir)/undo_io.c
HFILES= bitops.h ext2fs.h ext2_io.h ext2_fs.h ext2_ext_attr.h ext3_extents.h \
tdb.h
@@ -583,3 +585,4 @@ tst_iscan.o: $(srcdir)/tst_iscan.c $(srcdir)/ext2_fs.h \
$(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h \
$(srcdir)/ext2_fs.h $(srcdir)/ext3_extents.h $(top_srcdir)/lib/et/com_err.h \
$(srcdir)/ext2_io.h $(top_builddir)/lib/ext2fs/ext2_err.h $(srcdir)/bitops.h
+undo_io.o: $(srcdir)/undo_io.c $(srcdir)/ext2_fs.h $(srcdir)/ext2fs.h
diff --git a/lib/ext2fs/ext2_io.h b/lib/ext2fs/ext2_io.h
index eada278..476eb4d 100644
--- a/lib/ext2fs/ext2_io.h
+++ b/lib/ext2fs/ext2_io.h
@@ -96,6 +96,11 @@ extern errcode_t io_channel_write_byte(io_channel channel,
/* unix_io.c */
extern io_manager unix_io_manager;
+/* undo_io.c */
+extern io_manager undo_io_manager;
+extern errcode_t set_undo_io_backing_manager(io_manager manager);
+extern errcode_t set_undo_io_backup_file(char *file_name);
+
/* test_io.c */
extern io_manager test_io_manager, test_io_backing_manager;
extern void (*test_io_cb_read_blk)
diff --git a/lib/ext2fs/undo_io.c b/lib/ext2fs/undo_io.c
new file mode 100644
index 0000000..de74912
--- /dev/null
+++ b/lib/ext2fs/undo_io.c
@@ -0,0 +1,486 @@
+/*
+ * undo_io.c --- This is the undo io manager that copies the old data that
+ * copies the old data being overwritten into a tdb database
+ *
+ * Copyright IBM Corporation, 2007
+ * Author Aneesh Kumar K.V <[email protected]>
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#define _LARGEFILE_SOURCE
+#define _LARGEFILE64_SOURCE
+
+#include <stdio.h>
+#include <string.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#if HAVE_ERRNO_H
+#include <errno.h>
+#endif
+#include <fcntl.h>
+#include <time.h>
+#ifdef __linux__
+#include <sys/utsname.h>
+#endif
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#if HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#if HAVE_SYS_RESOURCE_H
+#include <sys/resource.h>
+#endif
+
+#include "tdb.h"
+
+#include "ext2_fs.h"
+#include "ext2fs.h"
+
+/*
+ * For checking structure magic numbers...
+ */
+
+#define EXT2_CHECK_MAGIC(struct, code) \
+ if ((struct)->magic != (code)) return (code)
+
+
+
+struct undo_private_data {
+ int magic;
+ TDB_CONTEXT *tdb;
+ char *tdb_file;
+
+ /* The backing io channel */
+ io_channel real;
+
+ /* to support offset in unix I/O manager */
+ ext2_loff_t offset;
+};
+
+static errcode_t undo_open(const char *name, int flags, io_channel *channel);
+static errcode_t undo_close(io_channel channel);
+static errcode_t undo_set_blksize(io_channel channel, int blksize);
+static errcode_t undo_read_blk(io_channel channel, unsigned long block,
+ int count, void *data);
+static errcode_t undo_write_blk(io_channel channel, unsigned long block,
+ int count, const void *data);
+static errcode_t undo_flush(io_channel channel);
+static errcode_t undo_write_byte(io_channel channel, unsigned long offset,
+ int size, const void *data);
+static errcode_t undo_set_option(io_channel channel, const char *option,
+ const char *arg);
+
+static struct struct_io_manager struct_undo_manager = {
+ EXT2_ET_MAGIC_IO_MANAGER,
+ "Undo I/O Manager",
+ undo_open,
+ undo_close,
+ undo_set_blksize,
+ undo_read_blk,
+ undo_write_blk,
+ undo_flush,
+ undo_write_byte,
+ undo_set_option
+};
+
+io_manager undo_io_manager = &struct_undo_manager;
+static io_manager undo_io_backing_manager ;
+static char *tdb_file ;
+static int tdb_data_size = 0;
+
+errcode_t set_undo_io_backing_manager(io_manager manager)
+{
+ /*
+ * We may want to do some validation later
+ */
+ undo_io_backing_manager = manager;
+ return 0;
+}
+
+errcode_t set_undo_io_backup_file(char *file_name)
+{
+ tdb_file = strdup(file_name);
+
+ if (tdb_file == NULL) {
+ return EXT2_ET_NO_MEMORY;
+ }
+
+ return 0;
+}
+
+
+static errcode_t undo_write_tdb(io_channel channel,
+ unsigned long block, int count)
+
+{
+ int size, loop_count = 0, i;
+ unsigned long block_num, backing_blk_num;
+ errcode_t retval = 0;
+ ext2_loff_t offset;
+ struct undo_private_data *data;
+ TDB_DATA tdb_key, tdb_data;
+ char *read_ptr;
+
+ data = (struct undo_private_data *) channel->private_data;
+
+
+ if (data->tdb == NULL) {
+ /*
+ * Transaction database not initialized
+ */
+ return 0;
+ }
+
+ /*
+ * Set the block size used to read for tdb
+ */
+ if (!tdb_data_size)
+ tdb_data_size = channel->block_size;
+
+ if (count == 1)
+ size = channel->block_size;
+ else {
+ if (count < 0)
+ size = -count;
+ else
+ size = count * channel->block_size;
+ }
+
+ /*
+ * Data is stored in tdb database as blocks of tdb_data_size size
+ * This helps in efficient lookup further.
+ *
+ * We divide the disk to blocks of tdb_data_size.
+ */
+
+ block_num = ((block*channel->block_size)+data->offset)/tdb_data_size;
+
+
+ loop_count = (size + tdb_data_size -1)/tdb_data_size;
+
+ tdb_transaction_start(data->tdb);
+ for (i = 0; i < loop_count; i++) {
+
+ block_num += i;
+ tdb_key.dptr = (unsigned char *)&block_num;
+ tdb_key.dsize = sizeof(block_num);
+
+ /*
+ * Check if we have the record already
+ */
+ if (tdb_exists(data->tdb, tdb_key)) {
+
+ /* Try the next block */
+ continue;
+ }
+
+ /*
+ * Read one block using the backing I/O manager
+ * The backing I/O manager block size may be
+ * different from the tdb_data_size.
+ * Also we need to recalcuate the block number with respect
+ * to the backing I/O manager.
+ */
+
+ offset = block_num * tdb_data_size;
+ backing_blk_num = (offset - data->offset) / channel->block_size;
+
+ count = tdb_data_size +
+ ((offset - data->offset) % channel->block_size);
+
+ retval = ext2fs_get_mem(count, &read_ptr);
+ if (retval)
+ return retval;
+
+ memset(read_ptr, 0, count);
+
+ retval = io_channel_read_blk(data->real,
+ backing_blk_num,
+ -count, read_ptr);
+ if (retval) {
+ free(read_ptr);
+ return retval;
+ }
+
+
+ tdb_data.dptr = read_ptr +
+ ((offset - data->offset) % channel->block_size);
+
+ tdb_data.dsize = tdb_data_size;
+
+#ifdef DEBUG
+ printf("Printing with key %ld data %x and size %d\n",
+ block_num,
+ tdb_data.dptr, tdb_data_size);
+#endif
+
+ retval = tdb_store(data->tdb, tdb_key, tdb_data, TDB_INSERT);
+ if (retval == -1) {
+ /*
+ * TDB_ERR_EXISTS cannot happen because we
+ * have already verified it doesn't exist
+ */
+ tdb_transaction_cancel(data->tdb);
+ retval = EXT2_ET_TDB_ERR_IO;
+ free(read_ptr);
+ return retval;
+
+ }
+ free(read_ptr);
+ }
+
+ tdb_transaction_commit(data->tdb);
+
+ return retval;
+
+}
+
+static TDB_CONTEXT *undo_setup_tdb(char *tdb_file,
+ struct undo_private_data *data)
+{
+ errcode_t retval;
+
+ data->tdb = tdb_open(tdb_file, 0, TDB_CLEAR_IF_FIRST,
+ O_RDWR | O_CREAT | O_TRUNC, 0600);
+ return data->tdb;
+
+}
+static errcode_t undo_open(const char *name, int flags, io_channel *channel)
+{
+ io_channel io = NULL;
+ struct undo_private_data *data = NULL;
+ errcode_t retval;
+ int open_flags;
+ struct stat st;
+
+ if (name == 0)
+ return EXT2_ET_BAD_DEVICE_NAME;
+ retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
+ if (retval)
+ return retval;
+ memset(io, 0, sizeof(struct struct_io_channel));
+ io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
+ retval = ext2fs_get_mem(sizeof(struct undo_private_data), &data);
+ if (retval)
+ goto cleanup;
+
+ io->manager = undo_io_manager;
+ retval = ext2fs_get_mem(strlen(name)+1, &io->name);
+ if (retval)
+ goto cleanup;
+
+ strcpy(io->name, name);
+ io->private_data = data;
+ io->block_size = 1024;
+ io->read_error = 0;
+ io->write_error = 0;
+ io->refcount = 1;
+
+ memset(data, 0, sizeof(struct undo_private_data));
+ data->magic = EXT2_ET_MAGIC_UNIX_IO_CHANNEL;
+
+ if (undo_io_backing_manager) {
+ retval = undo_io_backing_manager->open(name, flags,
+ &data->real);
+ if (retval)
+ goto cleanup;
+ } else {
+ data->real = 0;
+ }
+
+ /* setup the tdb file */
+ if (undo_setup_tdb(tdb_file, data) == NULL )
+ goto cleanup;
+
+ *channel = io;
+ return 0;
+
+cleanup:
+ if (data->real)
+ io_channel_close(data->real);
+
+ if (data)
+ ext2fs_free_mem(&data);
+
+ if (io)
+ ext2fs_free_mem(&io);
+
+ return retval;
+}
+
+static errcode_t undo_close(io_channel channel)
+{
+ struct undo_private_data *data;
+ errcode_t retval = 0;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct undo_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ if (--channel->refcount > 0)
+ return 0;
+
+ if (data->real)
+ retval = io_channel_close(data->real);
+
+ if (data->tdb)
+ tdb_close(data->tdb);
+
+ ext2fs_free_mem(&channel->private_data);
+ if (channel->name)
+ ext2fs_free_mem(&channel->name);
+ ext2fs_free_mem(&channel);
+
+ return retval;
+}
+
+static errcode_t undo_set_blksize(io_channel channel, int blksize)
+{
+ struct undo_private_data *data;
+ errcode_t retval;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct undo_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ if (data->real)
+ retval = io_channel_set_blksize(data->real, blksize);
+
+ channel->block_size = blksize;
+ return retval;
+}
+
+
+static errcode_t undo_read_blk(io_channel channel, unsigned long block,
+ int count, void *buf)
+{
+ errcode_t retval;
+ struct undo_private_data *data;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct undo_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ if (data->real)
+ retval = io_channel_read_blk(data->real, block, count, buf);
+
+ return retval;
+}
+
+static errcode_t undo_write_blk(io_channel channel, unsigned long block,
+ int count, const void *buf)
+{
+ struct undo_private_data *data;
+ errcode_t retval = 0;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct undo_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ /*
+ * First write the existing content into database
+ */
+ retval = undo_write_tdb(channel, block, count);
+ if (retval)
+ return retval;
+
+
+ if (data->real)
+ retval = io_channel_write_blk(data->real, block, count, buf);
+
+ return retval;
+
+}
+
+static errcode_t undo_write_byte(io_channel channel, unsigned long offset,
+ int size, const void *buf)
+{
+ struct undo_private_data *data;
+ errcode_t retval = 0;
+ ssize_t actual;
+ ext2_loff_t location;
+ unsigned long blk_num, count;;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct undo_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ location = offset + data->offset;
+ blk_num = location/channel->block_size;
+ /*
+ * the size specified may spread across multiple blocks
+ * also make sure we account for the fact that block start
+ * offset for tdb is different from the backing I/O manager
+ * due to possible different block size
+ */
+ count = (size + (location % channel->block_size) +
+ channel->block_size -1)/channel->block_size;
+
+ retval = undo_write_tdb(channel, blk_num, count);
+ if (retval)
+ return retval;
+
+ if (data->real && data->real->manager->write_byte)
+ retval = io_channel_write_byte(data->real, offset, size, buf);
+
+ return retval;
+}
+
+/*
+ * Flush data buffers to disk.
+ */
+static errcode_t undo_flush(io_channel channel)
+{
+ errcode_t retval = 0;
+ struct undo_private_data *data;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct undo_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ if (data->real)
+ retval = io_channel_flush(data->real);
+
+ return retval;
+}
+
+static errcode_t undo_set_option(io_channel channel, const char *option,
+ const char *arg)
+{
+ errcode_t retval = 0;
+ struct undo_private_data *data;
+ unsigned long tmp;
+ char *end;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct undo_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ /*
+ * Need to support offset option to work with
+ * Unix I/O manager
+ */
+ if (data->real && data->real->manager->set_option) {
+
+ retval = data->real->manager->set_option(data->real,
+ option, arg);
+ }
+
+ if (!retval && !strcmp(option, "offset")) {
+ if (!arg)
+ return EXT2_ET_INVALID_ARGUMENT;
+
+ tmp = strtoul(arg, &end, 0);
+ if (*end)
+ return EXT2_ET_INVALID_ARGUMENT;
+ data->offset = tmp;
+ }
+
+ return retval;
+}
--
1.5.3.rc0.63.gc956-dirty
From: Aneesh Kumar K.V <[email protected]>
undoe2fs can be used to replay the transaction saved
in the transaction file using undo I/O Manager
Signed-off-by: Aneesh Kumar K.V <[email protected]>
---
misc/Makefile.in | 10 ++++++++--
misc/undoe2fs.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 56 insertions(+), 2 deletions(-)
create mode 100644 misc/undoe2fs.c
diff --git a/misc/Makefile.in b/misc/Makefile.in
index ccad78c..51bb17a 100644
--- a/misc/Makefile.in
+++ b/misc/Makefile.in
@@ -15,7 +15,7 @@ INSTALL = @INSTALL@
@IMAGER_CMT@E2IMAGE_MAN= e2image.8
SPROGS= mke2fs badblocks tune2fs dumpe2fs blkid logsave \
- $(E2IMAGE_PROG) @FSCK_PROG@
+ $(E2IMAGE_PROG) @FSCK_PROG@ undoe2fs
USPROGS= mklost+found filefrag
SMANPAGES= tune2fs.8 mklost+found.8 mke2fs.8 dumpe2fs.8 badblocks.8 \
e2label.8 findfs.8 blkid.8 $(E2IMAGE_MAN) \
@@ -39,6 +39,7 @@ E2IMAGE_OBJS= e2image.o
FSCK_OBJS= fsck.o base_device.o
BLKID_OBJS= blkid.o
FILEFRAG_OBJS= filefrag.o
+UNDOE2FS_OBJS= undoe2fs.o
XTRA_CFLAGS= -I$(srcdir)/../e2fsck -I.
@@ -47,7 +48,7 @@ SRCS= $(srcdir)/tune2fs.c $(srcdir)/mklost+found.c $(srcdir)/mke2fs.c \
$(srcdir)/badblocks.c $(srcdir)/fsck.c $(srcdir)/util.c \
$(srcdir)/uuidgen.c $(srcdir)/blkid.c $(srcdir)/logsave.c \
$(srcdir)/filefrag.c $(srcdir)/base_device.c \
- $(srcdir)/../e2fsck/profile.c
+ $(srcdir)/../e2fsck/profile.c $(srcdir)/undoe2fs.c
LIBS= $(LIBEXT2FS) $(LIBCOM_ERR)
DEPLIBS= $(LIBEXT2FS) $(LIBCOM_ERR)
@@ -108,6 +109,10 @@ e2image: $(E2IMAGE_OBJS) $(DEPLIBS)
@echo " LD $@"
@$(CC) $(ALL_LDFLAGS) -o e2image $(E2IMAGE_OBJS) $(LIBS) $(LIBINTL)
+undoe2fs: $(UNDOE2FS_OBJS) $(DEPLIBS)
+ @echo " LD $@"
+ @$(CC) $(ALL_LDFLAGS) -o undoe2fs $(UNDOE2FS_OBJS) $(LIBS)
+
base_device: base_device.c
@echo " LD $@"
@$(CC) $(ALL_CFLAGS) $(ALL_LDFLAGS) $(srcdir)/base_device.c \
@@ -434,3 +439,4 @@ filefrag.o: $(srcdir)/filefrag.c
base_device.o: $(srcdir)/base_device.c $(srcdir)/fsck.h
profile.o: $(srcdir)/../e2fsck/profile.c $(top_srcdir)/lib/et/com_err.h \
$(srcdir)/../e2fsck/profile.h prof_err.h
+undoe2fs.o: $(srcdir)/undoe2fs.c $(top_srcdir)/lib/ext2fs/tdb.h
diff --git a/misc/undoe2fs.c b/misc/undoe2fs.c
new file mode 100644
index 0000000..c209878
--- /dev/null
+++ b/misc/undoe2fs.c
@@ -0,0 +1,48 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#if HAVE_ERRNO_H
+#include <errno.h>
+#endif
+#include "ext2fs/tdb.h"
+
+void usage(char *prg_name)
+{
+ fprintf(stderr, "Usage: %s <transaction file> <filesystem>\n", prg_name);
+ exit(1);
+
+}
+
+
+main(int argc, char *argv[])
+{
+ TDB_CONTEXT *tdb;
+ TDB_DATA key, data;
+ unsigned long blk_num;
+ unsigned long long int location;
+ int fd;
+
+ if (argc != 3)
+ usage(argv[0]);
+
+ tdb = tdb_open(argv[1], 0, 0, O_RDONLY, 0600);
+
+ if (!tdb) {
+ printf("Failed tdb_open %s\n", strerror(errno));
+ exit(1);
+ }
+
+ fd = open(argv[2], O_WRONLY);
+
+ for (key = tdb_firstkey(tdb); key.dptr; key = tdb_nextkey(tdb, key)) {
+ data = tdb_fetch(tdb, key);
+ blk_num = *(unsigned long *)key.dptr;
+ location = blk_num * data.dsize;
+ printf("Replayed transaction of size %d at location %ld\n", data.dsize, blk_num);
+ lseek(fd, location, SEEK_SET);
+ write(fd, data.dptr, data.dsize);
+ }
+ close(fd);
+ tdb_close(tdb);
+
+}
--
1.5.3.rc0.63.gc956-dirty