From: Aneesh Kumar K.V <[EMAIL PROTECTED]>
Signed-off-by: Aneesh Kumar K.V <[EMAIL PROTECTED]>
---
lib/ext2fs/Makefile.in | 6 +
lib/ext2fs/ext2_io.h | 3 +
lib/ext2fs/unix_cow_io.c | 864 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 873 insertions(+), 0 deletions(-)
create mode 100644 lib/ext2fs/unix_cow_io.c
diff --git a/lib/ext2fs/Makefile.in b/lib/ext2fs/Makefile.in
index 799659e..938f2d3 100644
--- a/lib/ext2fs/Makefile.in
+++ b/lib/ext2fs/Makefile.in
@@ -64,6 +64,7 @@ OBJS= $(DEBUGFS_LIB_OBJS) $(RESIZE_LIB_OBJS)
$(E2IMAGE_LIB_OBJS) \
rw_bitmaps.o \
swapfs.o \
unix_io.o \
+ unix_cow_io.o \
unlink.o \
valid_blk.o \
version.o
@@ -126,6 +127,7 @@ SRCS= ext2_err.c \
$(srcdir)/swapfs.c \
$(srcdir)/test_io.c \
$(srcdir)/unix_io.c \
+ $(srcdir)/unix_cow_io.c \
$(srcdir)/unlink.c \
$(srcdir)/valid_blk.c \
$(srcdir)/version.c \
@@ -512,6 +514,10 @@ unix_io.o: $(srcdir)/unix_io.c $(srcdir)/ext2_fs.h \
$(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h \
$(srcdir)/ext2_fs.h $(top_srcdir)/lib/et/com_err.h $(srcdir)/ext2_io.h \
$(top_builddir)/lib/ext2fs/ext2_err.h $(srcdir)/bitops.h
+unix_cow_io.o: $(srcdir)/unix_cow_io.c $(srcdir)/ext2_fs.h \
+ $(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h \
+ $(srcdir)/ext2_fs.h $(top_srcdir)/lib/et/com_err.h $(srcdir)/ext2_io.h \
+ $(top_builddir)/lib/ext2fs/ext2_err.h $(srcdir)/bitops.h
unlink.o: $(srcdir)/unlink.c $(srcdir)/ext2_fs.h \
$(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h \
$(srcdir)/ext2_fs.h $(top_srcdir)/lib/et/com_err.h $(srcdir)/ext2_io.h \
diff --git a/lib/ext2fs/ext2_io.h b/lib/ext2fs/ext2_io.h
index eada278..cdfdd51 100644
--- a/lib/ext2fs/ext2_io.h
+++ b/lib/ext2fs/ext2_io.h
@@ -96,6 +96,9 @@ extern errcode_t io_channel_write_byte(io_channel channel,
/* unix_io.c */
extern io_manager unix_io_manager;
+/* unix_cow_io.c */
+extern io_manager unix_cow_io_manager;
+
/* 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/unix_cow_io.c b/lib/ext2fs/unix_cow_io.c
new file mode 100644
index 0000000..aeebec8
--- /dev/null
+++ b/lib/ext2fs/unix_cow_io.c
@@ -0,0 +1,864 @@
+/*
+ * unix_cow_io.c --- This is the Unix (well, really POSIX) implementation
+ * of the COW I/O manager.
+ *
+ * Implements a one-block write-through cache.
+ *
+ * Includes support for Windows NT support under Cygwin.
+ *
+ * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
+ * 2002 by Theodore Ts'o.
+ *
+ * %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 unix_cache {
+ char *buf;
+ unsigned long block;
+ int access_time;
+ unsigned dirty:1;
+ unsigned in_use:1;
+};
+
+#define CACHE_SIZE 8
+#define WRITE_DIRECT_SIZE 4 /* Must be smaller than CACHE_SIZE */
+#define READ_DIRECT_SIZE 4 /* Should be smaller than CACHE_SIZE */
+
+struct unix_cow_private_data {
+ int magic;
+ int dev;
+ int flags;
+ int access_time;
+ ext2_loff_t offset;
+ TDB_CONTEXT *tdb;
+ char *tdb_file;
+ struct unix_cache cache[CACHE_SIZE];
+};
+
+static errcode_t unix_cow_open(const char *name, int flags, io_channel
*channel);
+static errcode_t unix_cow_close(io_channel channel);
+static errcode_t unix_cow_set_blksize(io_channel channel, int blksize);
+static errcode_t unix_cow_read_blk(io_channel channel, unsigned long block,
+ int count, void *data);
+static errcode_t unix_cow_write_blk(io_channel channel, unsigned long block,
+ int count, const void *data);
+static errcode_t unix_cow_flush(io_channel channel);
+static errcode_t unix_cow_write_byte(io_channel channel, unsigned long offset,
+ int size, const void *data);
+static errcode_t unix_cow_set_option(io_channel channel, const char *option,
+ const char *arg);
+
+static void reuse_cache(io_channel channel, struct unix_cow_private_data *data,
+ struct unix_cache *cache, unsigned long block);
+
+/* __FreeBSD_kernel__ is defined by GNU/kFreeBSD - the FreeBSD kernel
+ * does not know buffered block devices - everything is raw. */
+#if defined(__CYGWIN__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+#define NEED_BOUNCE_BUFFER
+#else
+#undef NEED_BOUNCE_BUFFER
+#endif
+
+static struct struct_io_manager struct_unix_cow_manager = {
+ EXT2_ET_MAGIC_IO_MANAGER,
+ "Unix COW_I/O Manager",
+ unix_cow_open,
+ unix_cow_close,
+ unix_cow_set_blksize,
+ unix_cow_read_blk,
+ unix_cow_write_blk,
+ unix_cow_flush,
+#ifdef NEED_BOUNCE_BUFFER
+ 0,
+#else
+ unix_cow_write_byte,
+#endif
+ unix_cow_set_option
+};
+
+io_manager unix_cow_io_manager = &struct_unix_cow_manager;
+
+/*
+ * Here are the raw I/O functions
+ */
+#ifndef NEED_BOUNCE_BUFFER
+static errcode_t raw_read_blk(io_channel channel,
+ struct unix_cow_private_data *data,
+ unsigned long block,
+ int count, void *buf)
+{
+ errcode_t retval;
+ ssize_t size;
+ ext2_loff_t location;
+ int actual = 0;
+
+ size = (count < 0) ? -count : count * channel->block_size;
+ location = ((ext2_loff_t) block * channel->block_size) + data->offset;
+ if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
+ retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
+ goto error_out;
+ }
+ actual = read(data->dev, buf, size);
+ if (actual != size) {
+ if (actual < 0)
+ actual = 0;
+ retval = EXT2_ET_SHORT_READ;
+ goto error_out;
+ }
+ return 0;
+
+error_out:
+ memset((char *) buf+actual, 0, size-actual);
+ if (channel->read_error)
+ retval = (channel->read_error)(channel, block, count, buf,
+ size, actual, retval);
+ return retval;
+}
+#else /* NEED_BOUNCE_BUFFER */
+/*
+ * Windows and FreeBSD block devices only allow sector alignment IO in offset
and size
+ */
+static errcode_t raw_read_blk(io_channel channel,
+ struct unix_cow_private_data *data,
+ unsigned long block,
+ int count, void *buf)
+{
+ errcode_t retval;
+ size_t size, alignsize, fragment;
+ ext2_loff_t location;
+ int total = 0, actual;
+#define BLOCKALIGN 512
+ char sector[BLOCKALIGN];
+
+ size = (count < 0) ? -count : count * channel->block_size;
+ location = ((ext2_loff_t) block * channel->block_size) + data->offset;
+#ifdef DEBUG
+ printf("count=%d, size=%d, block=%lu, blk_size=%d, location=%llx\n",
+ count, size, block, channel->block_size, (long
long)location);
+#endif
+ if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
+ retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
+ goto error_out;
+ }
+ fragment = size % BLOCKALIGN;
+ alignsize = size - fragment;
+ if (alignsize) {
+ actual = read(data->dev, buf, alignsize);
+ if (actual != alignsize)
+ goto short_read;
+ }
+ if (fragment) {
+ actual = read(data->dev, sector, BLOCKALIGN);
+ if (actual != BLOCKALIGN)
+ goto short_read;
+ memcpy(buf+alignsize, sector, fragment);
+ }
+ return 0;
+
+short_read:
+ if (actual>0)
+ total += actual;
+ retval = EXT2_ET_SHORT_READ;
+
+error_out:
+ memset((char *) buf+total, 0, size-actual);
+ if (channel->read_error)
+ retval = (channel->read_error)(channel, block, count, buf,
+ size, actual, retval);
+ return retval;
+}
+#endif
+
+static errcode_t unix_cow_write_tdb(struct unix_cow_private_data * data,
+ ext2_loff_t location, int size)
+
+{
+ TDB_DATA tdb_key, tdb_data;
+ errcode_t retval = 0;
+ int actual = 0, rsize = size;
+ ext2_loff_t cur_loc ;
+
+ if (data->tdb == NULL) {
+ /*
+ * Transaction database not initialized
+ */
+ return 0;
+ }
+
+ tdb_key.dptr = (unsigned char *)&location;
+ tdb_key.dsize = sizeof(location);
+
+ /* insert a new entry and refuse to overwrite an existing entry */
+ /* See if we have an entry already */
+ tdb_data = tdb_fetch(data->tdb, tdb_key);
+ if (tdb_data.dptr) {
+ if (tdb_data.dsize == size) {
+ /*
+ * already we wrote something at this
+ * location with the same size
+ */
+ return 0;
+ } else {
+ /*
+ * Write at the same location but with different size
+ */
+ rsize = size - tdb_data.dsize ;
+ if (rsize < 0) {
+ /*
+ * smaller chunk. return doing nothing
+ */
+ return 0;
+ }
+ location += tdb_data.dsize;
+ }
+ free(tdb_data.dptr);
+ }
+
+ retval = ext2fs_get_mem(rsize, &(tdb_data.dptr));
+ if (retval) {
+ return retval;
+ }
+
+ if ((cur_loc = ext2fs_llseek(data->dev, 0, SEEK_CUR)) == -1) {
+ retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
+ goto error_out_lseek;
+ }
+
+ if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
+ retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
+ goto error_out_lseek;
+ }
+
+ actual = read(data->dev, tdb_data.dptr, rsize);
+ if (actual != rsize) {
+ /*
+ * eventhough it is read we still are doing a write
+ * so return error that is related to write
+ */
+ retval = EXT2_ET_SHORT_WRITE;
+ goto error_out;
+ }
+
+ tdb_data.dsize = rsize;
+
+#ifdef DEBUG
+ printf("Printing with key %lld data %x and size %d\n", location,
tdb_data.dptr, rsize);
+#endif
+
+ retval = tdb_store(data->tdb, tdb_key, tdb_data, TDB_INSERT);
+ if (retval == -1) {
+ /* FIXME!! Not sure what should be the error */
+ retval = EXT2_ET_SHORT_WRITE;
+ goto error_out;
+
+ }
+
+error_out:
+ /* Move the location back */
+ if (ext2fs_llseek(data->dev, cur_loc, SEEK_SET) != cur_loc) {
+ retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
+ goto error_out;
+ }
+
+error_out_lseek:
+ free(tdb_data.dptr);
+ return retval;
+
+}
+static errcode_t raw_write_blk(io_channel channel,
+ struct unix_cow_private_data *data,
+ unsigned long block,
+ int count, const void *buf)
+{
+ ssize_t size;
+ ext2_loff_t location;
+ int actual = 0;
+ errcode_t retval;
+ TDB_DATA tdb_key, tdb_data;
+
+ if (count == 1)
+ size = channel->block_size;
+ else {
+ if (count < 0)
+ size = -count;
+ else
+ size = count * channel->block_size;
+ }
+
+ location = ((ext2_loff_t) block * channel->block_size) + data->offset;
+ if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
+ retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
+ goto error_out;
+ }
+
+
+ /*
+ * before writing to the location read the data from the location
+ * and put it in the database. This will help us to replay the
+ * database content in cae of crash later
+ */
+ retval = unix_cow_write_tdb(data, location, size);
+ if (retval) {
+ goto error_out;
+ }
+
+ actual = write(data->dev, buf, size);
+ if (actual != size) {
+ retval = EXT2_ET_SHORT_WRITE;
+ goto error_out;
+ }
+ return 0;
+
+error_out:
+ if (channel->write_error)
+ retval = (channel->write_error)(channel, block, count, buf,
+ size, actual, retval);
+ return retval;
+}
+
+
+/*
+ * Here we implement the cache functions
+ */
+
+/* Allocate the cache buffers */
+static errcode_t alloc_cache(io_channel channel,
+ struct unix_cow_private_data *data)
+{
+ errcode_t retval;
+ struct unix_cache *cache;
+ int i;
+
+ data->access_time = 0;
+ for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
+ cache->block = 0;
+ cache->access_time = 0;
+ cache->dirty = 0;
+ cache->in_use = 0;
+ if ((retval = ext2fs_get_mem(channel->block_size,
+ &cache->buf)))
+ return retval;
+ }
+ return 0;
+}
+
+/* Free the cache buffers */
+static void free_cache(struct unix_cow_private_data *data)
+{
+ struct unix_cache *cache;
+ int i;
+
+ data->access_time = 0;
+ for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
+ cache->block = 0;
+ cache->access_time = 0;
+ cache->dirty = 0;
+ cache->in_use = 0;
+ if (cache->buf)
+ ext2fs_free_mem(&cache->buf);
+ cache->buf = 0;
+ }
+}
+
+#ifndef NO_IO_CACHE
+/*
+ * Try to find a block in the cache. If the block is not found, and
+ * eldest is a non-zero pointer, then fill in eldest with the cache
+ * entry to that should be reused.
+ */
+static struct unix_cache *find_cached_block(struct unix_cow_private_data *data,
+ unsigned long block,
+ struct unix_cache **eldest)
+{
+ struct unix_cache *cache, *unused_cache, *oldest_cache;
+ int i;
+
+ unused_cache = oldest_cache = 0;
+ for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
+ if (!cache->in_use) {
+ if (!unused_cache)
+ unused_cache = cache;
+ continue;
+ }
+ if (cache->block == block) {
+ cache->access_time = ++data->access_time;
+ return cache;
+ }
+ if (!oldest_cache ||
+ (cache->access_time < oldest_cache->access_time))
+ oldest_cache = cache;
+ }
+ if (eldest)
+ *eldest = (unused_cache) ? unused_cache : oldest_cache;
+ return 0;
+}
+
+/*
+ * Reuse a particular cache entry for another block.
+ */
+static void reuse_cache(io_channel channel, struct unix_cow_private_data *data,
+ struct unix_cache *cache, unsigned long block)
+{
+ if (cache->dirty && cache->in_use)
+ raw_write_blk(channel, data, cache->block, 1, cache->buf);
+
+ cache->in_use = 1;
+ cache->dirty = 0;
+ cache->block = block;
+ cache->access_time = ++data->access_time;
+}
+
+/*
+ * Flush all of the blocks in the cache
+ */
+static errcode_t flush_cached_blocks(io_channel channel,
+ struct unix_cow_private_data *data,
+ int invalidate)
+
+{
+ struct unix_cache *cache;
+ errcode_t retval, retval2;
+ int i;
+
+ retval2 = 0;
+ for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
+ if (!cache->in_use)
+ continue;
+
+ if (invalidate)
+ cache->in_use = 0;
+
+ if (!cache->dirty)
+ continue;
+
+ retval = raw_write_blk(channel, data,
+ cache->block, 1, cache->buf);
+ if (retval)
+ retval2 = retval;
+ else
+ cache->dirty = 0;
+ }
+ return retval2;
+}
+#endif /* NO_IO_CACHE */
+
+static void unix_cow_setup_tdb(char *tdb_file,
+ struct unix_cow_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;
+
+}
+static errcode_t unix_cow_open(const char *name, int flags, io_channel
*channel)
+{
+ io_channel io = NULL;
+ struct unix_cow_private_data *data = NULL;
+ errcode_t retval;
+ int open_flags;
+ struct stat st;
+#ifdef __linux__
+ struct utsname ut;
+#endif
+
+ 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 unix_cow_private_data), &data);
+ if (retval)
+ goto cleanup;
+
+ io->manager = unix_cow_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 unix_cow_private_data));
+ data->magic = EXT2_ET_MAGIC_UNIX_IO_CHANNEL;
+
+ if ((retval = alloc_cache(io, data)))
+ goto cleanup;
+
+ open_flags = (flags & IO_FLAG_RW) ? O_RDWR : O_RDONLY;
+ if (flags & IO_FLAG_EXCLUSIVE)
+ open_flags |= O_EXCL;
+#ifdef HAVE_OPEN64
+ data->dev = open64(io->name, open_flags);
+#else
+ data->dev = open(io->name, open_flags);
+#endif
+ if (data->dev < 0) {
+ retval = errno;
+ goto cleanup;
+ }
+
+#ifdef __linux__
+#undef RLIM_INFINITY
+#if (defined(__alpha__) || ((defined(__sparc__) || defined(__mips__)) &&
(SIZEOF_LONG == 4)))
+#define RLIM_INFINITY ((unsigned long)(~0UL>>1))
+#else
+#define RLIM_INFINITY (~0UL)
+#endif
+ /*
+ * Work around a bug in 2.4.10-2.4.18 kernels where writes to
+ * block devices are wrongly getting hit by the filesize
+ * limit. This workaround isn't perfect, since it won't work
+ * if glibc wasn't built against 2.2 header files. (Sigh.)
+ *
+ */
+ if ((flags & IO_FLAG_RW) &&
+ (uname(&ut) == 0) &&
+ ((ut.release[0] == '2') && (ut.release[1] == '.') &&
+ (ut.release[2] == '4') && (ut.release[3] == '.') &&
+ (ut.release[4] == '1') && (ut.release[5] >= '0') &&
+ (ut.release[5] < '8')) &&
+ (fstat(data->dev, &st) == 0) &&
+ (S_ISBLK(st.st_mode))) {
+ struct rlimit rlim;
+
+ rlim.rlim_cur = rlim.rlim_max = (unsigned long) RLIM_INFINITY;
+ setrlimit(RLIMIT_FSIZE, &rlim);
+ getrlimit(RLIMIT_FSIZE, &rlim);
+ if (((unsigned long) rlim.rlim_cur) <
+ ((unsigned long) rlim.rlim_max)) {
+ rlim.rlim_cur = rlim.rlim_max;
+ setrlimit(RLIMIT_FSIZE, &rlim);
+ }
+ }
+#endif
+
+ *channel = io;
+ return 0;
+
+cleanup:
+ if (data) {
+ free_cache(data);
+ ext2fs_free_mem(&data);
+ }
+ if (io)
+ ext2fs_free_mem(&io);
+ return retval;
+}
+
+static errcode_t unix_cow_close(io_channel channel)
+{
+ struct unix_cow_private_data *data;
+ errcode_t retval = 0;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct unix_cow_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ if (--channel->refcount > 0)
+ return 0;
+
+#ifndef NO_IO_CACHE
+ retval = flush_cached_blocks(channel, data, 0);
+#endif
+ if (data->tdb)
+ tdb_close(data->tdb);
+
+ if (close(data->dev) < 0)
+ retval = errno;
+ free_cache(data);
+
+ ext2fs_free_mem(&channel->private_data);
+ if (channel->name)
+ ext2fs_free_mem(&channel->name);
+ ext2fs_free_mem(&channel);
+ return retval;
+}
+
+static errcode_t unix_cow_set_blksize(io_channel channel, int blksize)
+{
+ struct unix_cow_private_data *data;
+ errcode_t retval;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct unix_cow_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ if (channel->block_size != blksize) {
+#ifndef NO_IO_CACHE
+ if ((retval = flush_cached_blocks(channel, data, 0)))
+ return retval;
+#endif
+
+ channel->block_size = blksize;
+ free_cache(data);
+ if ((retval = alloc_cache(channel, data)))
+ return retval;
+ }
+ return 0;
+}
+
+
+static errcode_t unix_cow_read_blk(io_channel channel, unsigned long block,
+ int count, void *buf)
+{
+ struct unix_cow_private_data *data;
+ struct unix_cache *cache, *reuse[READ_DIRECT_SIZE];
+ errcode_t retval;
+ char *cp;
+ int i, j;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct unix_cow_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+#ifdef NO_IO_CACHE
+ return raw_read_blk(channel, data, block, count, buf);
+#else
+ /*
+ * If we're doing an odd-sized read or a very large read,
+ * flush out the cache and then do a direct read.
+ */
+ if (count < 0 || count > WRITE_DIRECT_SIZE) {
+ if ((retval = flush_cached_blocks(channel, data, 0)))
+ return retval;
+ return raw_read_blk(channel, data, block, count, buf);
+ }
+
+ cp = buf;
+ while (count > 0) {
+ /* If it's in the cache, use it! */
+ if ((cache = find_cached_block(data, block, &reuse[0]))) {
+#ifdef DEBUG
+ printf("Using cached block %lu\n", block);
+#endif
+ memcpy(cp, cache->buf, channel->block_size);
+ count--;
+ block++;
+ cp += channel->block_size;
+ continue;
+ }
+ /*
+ * Find the number of uncached blocks so we can do a
+ * single read request
+ */
+ for (i=1; i < count; i++)
+ if (find_cached_block(data, block+i, &reuse[i]))
+ break;
+#ifdef DEBUG
+ printf("Reading %d blocks starting at %lu\n", i, block);
+#endif
+ if ((retval = raw_read_blk(channel, data, block, i, cp)))
+ return retval;
+
+ /* Save the results in the cache */
+ for (j=0; j < i; j++) {
+ count--;
+ cache = reuse[j];
+ reuse_cache(channel, data, cache, block++);
+ memcpy(cache->buf, cp, channel->block_size);
+ cp += channel->block_size;
+ }
+ }
+ return 0;
+#endif /* NO_IO_CACHE */
+}
+
+static errcode_t unix_cow_write_blk(io_channel channel, unsigned long block,
+ int count, const void *buf)
+{
+ struct unix_cow_private_data *data;
+ struct unix_cache *cache, *reuse;
+ errcode_t retval = 0;
+ const char *cp;
+ int writethrough;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct unix_cow_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+#ifdef NO_IO_CACHE
+ return raw_write_blk(channel, data, block, count, buf);
+#else
+ /*
+ * If we're doing an odd-sized write or a very large write,
+ * flush out the cache completely and then do a direct write.
+ */
+ if (count < 0 || count > WRITE_DIRECT_SIZE) {
+ if ((retval = flush_cached_blocks(channel, data, 1)))
+ return retval;
+ return raw_write_blk(channel, data, block, count, buf);
+ }
+
+ /*
+ * For a moderate-sized multi-block write, first force a write
+ * if we're in write-through cache mode, and then fill the
+ * cache with the blocks.
+ */
+ writethrough = channel->flags & CHANNEL_FLAGS_WRITETHROUGH;
+ if (writethrough)
+ retval = raw_write_blk(channel, data, block, count, buf);
+
+ cp = buf;
+ while (count > 0) {
+ cache = find_cached_block(data, block, &reuse);
+ if (!cache) {
+ cache = reuse;
+ reuse_cache(channel, data, cache, block);
+ }
+ memcpy(cache->buf, cp, channel->block_size);
+ cache->dirty = !writethrough;
+ count--;
+ block++;
+ cp += channel->block_size;
+ }
+ return retval;
+#endif /* NO_IO_CACHE */
+}
+
+
+static errcode_t unix_cow_write_byte(io_channel channel, unsigned long offset,
+ int size, const void *buf)
+{
+ struct unix_cow_private_data *data;
+ errcode_t retval = 0;
+ ssize_t actual;
+ ext2_loff_t location;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct unix_cow_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+#ifndef NO_IO_CACHE
+ /*
+ * Flush out the cache completely
+ */
+ if ((retval = flush_cached_blocks(channel, data, 1)))
+ return retval;
+#endif
+
+ if (lseek(data->dev, offset + data->offset, SEEK_SET) < 0)
+ return errno;
+
+ /*
+ * before writing to the location read the data from the location
+ * and put it in the database. This will help us to replay the
+ * database content in cae of crash later
+ */
+
+ location = offset + data->offset;
+ retval = unix_cow_write_tdb(data, location, size);
+ if (retval)
+ return retval;
+
+ actual = write(data->dev, buf, size);
+ if (actual != size)
+ return EXT2_ET_SHORT_WRITE;
+
+ return 0;
+}
+
+/*
+ * Flush data buffers to disk.
+ */
+static errcode_t unix_cow_flush(io_channel channel)
+{
+ struct unix_cow_private_data *data;
+ errcode_t retval = 0;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct unix_cow_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+#ifndef NO_IO_CACHE
+ retval = flush_cached_blocks(channel, data, 0);
+#endif
+ fsync(data->dev);
+ return retval;
+}
+
+static errcode_t unix_cow_set_option(io_channel channel, const char *option,
+ const char *arg)
+{
+ struct unix_cow_private_data *data;
+ unsigned long tmp;
+ char *end;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct unix_cow_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ if (!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 0;
+ }
+ if (!strcmp(option, "tdbfilename")) {
+ if (!arg)
+ return EXT2_ET_INVALID_ARGUMENT;
+
+ data->tdb_file = strdup(arg);
+ /*
+ * Initialize the database context
+ * We need to do it in set_option because when
+ * unix_cow_open is called we don't have the
+ * tdb file name set.
+ */
+ unix_cow_setup_tdb(data->tdb_file, data);
+ return 0;
+ }
+ return EXT2_ET_INVALID_ARGUMENT;
+}
--
1.5.2.rc0.71.g4342-dirty
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