This I/O manager helps in stacking different I/O managers.
For example one can stack the undo I/O manager on top
of Unix I/O manager to achieve the undo functionality.
Signed-off-by: Aneesh Kumar K.V <[EMAIL PROTECTED]>
---
lib/ext2fs/Makefile.in | 10 +-
lib/ext2fs/ext2_io.h | 4 +
lib/ext2fs/stack_io.c | 419 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 431 insertions(+), 2 deletions(-)
create mode 100644 lib/ext2fs/stack_io.c
diff --git a/lib/ext2fs/Makefile.in b/lib/ext2fs/Makefile.in
index 799659e..f5d141a 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 \
+ stack_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)/stack_io.c
HFILES= bitops.h ext2fs.h ext2_io.h ext2_fs.h ext2_ext_attr.h ext3_extents.h
HFILES_IN= ext2_err.h ext2_types.h
@@ -550,3 +552,7 @@ 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 $(top_srcdir)/lib/et/com_err.h $(srcdir)/ext2_io.h \
$(top_builddir)/lib/ext2fs/ext2_err.h $(srcdir)/bitops.h
+stack_io.o: $(srcdir)/stack_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
diff --git a/lib/ext2fs/ext2_io.h b/lib/ext2fs/ext2_io.h
index eada278..65a294e 100644
--- a/lib/ext2fs/ext2_io.h
+++ b/lib/ext2fs/ext2_io.h
@@ -96,6 +96,10 @@ extern errcode_t io_channel_write_byte(io_channel channel,
/* unix_io.c */
extern io_manager unix_io_manager;
+/* stack_io.c */
+extern struct struct_io_manager *stack_io_manager_init(void);
+extern errcode_t stack_push_io_manager(struct struct_io_manager *stack,
+ struct struct_io_manager *io);
/* 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/stack_io.c b/lib/ext2fs/stack_io.c
new file mode 100644
index 0000000..5adfe4d
--- /dev/null
+++ b/lib/ext2fs/stack_io.c
@@ -0,0 +1,419 @@
+/*
+ * stack_io.c --- This is the io manager used to stack different io managers.
+ *
+ * Copyright (C) 1996 Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#include <stdio.h>
+#include <string.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <fcntl.h>
+#include <time.h>
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#if HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_PRCTL_H
+#include <sys/prctl.h>
+#else
+#define PR_GET_DUMPABLE 3
+#endif
+#if (!defined(HAVE_PRCTL) && defined(linux))
+#include <sys/syscall.h>
+#endif
+
+#include "ext2_fs.h"
+#include "ext2fs.h"
+#include "kernel-list.h"
+
+/*
+ * For checking structure magic numbers...
+ */
+
+#define EXT2_CHECK_MAGIC(struct, code) \
+ if ((struct)->magic != (code)) return (code)
+
+#define EXT2_ET_MAGIC_STACK_IO_CHANNEL (2133571428L)
+
+struct stack_private_data {
+ int magic;
+ struct list_head st_elements;
+};
+
+struct stack_element {
+ struct struct_io_manager *io;
+ struct struct_io_channel *channel;
+ struct list_head list;
+};
+
+
+static errcode_t stack_open(const char *name, int flags, io_channel *channel);
+static errcode_t stack_close(io_channel channel);
+static errcode_t stack_set_blksize(io_channel channel, int blksize);
+static errcode_t stack_read_blk(io_channel channel, unsigned long block,
+ int count, void *data);
+static errcode_t stack_write_blk(io_channel channel, unsigned long block,
+ int count, const void *data);
+static errcode_t stack_flush(io_channel channel);
+static errcode_t stack_write_byte(io_channel channel, unsigned long offset,
+ int count, const void *buf);
+static errcode_t stack_set_option(io_channel channel, const char *option,
+ const char *arg);
+
+static struct struct_io_manager struct_stack_manager = {
+ .magic = EXT2_ET_MAGIC_IO_MANAGER,
+ .name = "Stack I/O Manager",
+ .open = stack_open,
+ .close = stack_close,
+ .set_blksize = stack_set_blksize,
+ .read_blk = stack_read_blk,
+ .write_blk = stack_write_blk,
+ .flush = stack_flush,
+ .write_byte = stack_write_byte,
+ .set_option = stack_set_option,
+};
+
+io_manager stack_io_manager = &struct_stack_manager;
+/* FIXME!! get rid of this. not thread safe */
+static struct stack_private_data private_data;
+struct struct_io_manager *stack_io_manager_init(void)
+{
+
+
+ INIT_LIST_HEAD(&(private_data.st_elements));
+ private_data.magic = EXT2_ET_MAGIC_STACK_IO_CHANNEL;
+
+ return stack_io_manager;
+
+}
+
+errcode_t stack_push_io_manager(struct struct_io_manager *stack, struct
struct_io_manager *io)
+{
+ errcode_t retval;
+ (void)(stack);
+ struct stack_element *element;
+ retval = ext2fs_get_mem(sizeof(struct stack_element), &element);
+ if (retval)
+ return retval;
+ element->io = io;
+ list_add(&(element->list), &(private_data.st_elements));
+
+ return 0;
+}
+
+
+static errcode_t stack_open(const char *name, int flags, io_channel *channel)
+{
+ io_channel io = NULL, stack_io_channel = NULL;
+ errcode_t retval;
+ char *value;
+ struct list_head *entry;
+ struct stack_element *element;
+
+ 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;
+
+ io->manager = stack_io_manager;
+ retval = ext2fs_get_mem(strlen(name)+1, &io->name);
+ if (retval)
+ goto cleanup;
+
+ strcpy(io->name, name);
+ io->private_data = &(private_data);
+ io->block_size = 1024;
+ io->read_error = 0;
+ io->write_error = 0;
+ io->refcount = 1;
+
+ /*
+ * Now call all the io managers open routine
+ */
+ list_for_each(entry, &(private_data.st_elements)) {
+
+ element = list_entry(entry, struct stack_element, list);
+ if (element->io) {
+ retval = element->io->open(name, flags,
+ &stack_io_channel);
+ if (retval) {
+ /*
+ * FIXME!! we need cleanup previous
+ * successfull I/O manager open
+ */
+ goto cleanup;
+ }
+ }
+ element->channel = stack_io_channel;
+ }
+
+ *channel = io;
+ return 0;
+
+cleanup:
+ if (io)
+ ext2fs_free_mem(&io);
+ return retval;
+}
+
+static errcode_t stack_io_channel_close(io_channel channel)
+{
+ if (channel && channel->manager->close)
+ return channel->manager->close(channel);
+
+ return 0;
+
+}
+
+static errcode_t stack_close(io_channel channel)
+{
+ struct stack_private_data *data;
+ struct list_head *entry;
+ struct stack_element *element;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct stack_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_STACK_IO_CHANNEL);
+
+ if (--channel->refcount > 0)
+ return 0;
+
+ list_for_each(entry, &(data->st_elements)) {
+ element = list_entry(entry, struct stack_element, list);
+ stack_io_channel_close(element->channel);
+ }
+
+ if (channel->name)
+ ext2fs_free_mem(&channel->name);
+ ext2fs_free_mem(&channel);
+
+ return 0;
+}
+
+static errcode_t stack_io_channel_set_blksize(io_channel channel, int blksize)
+{
+ if (channel && channel->manager->set_blksize)
+ return channel->manager->set_blksize(channel, blksize);
+
+ return 0;
+
+}
+static errcode_t stack_set_blksize(io_channel channel, int blksize)
+{
+ struct stack_private_data *data;
+ struct list_head *entry;
+ struct stack_element *element;
+ errcode_t retval = 0;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct stack_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_STACK_IO_CHANNEL);
+
+ list_for_each(entry, &(data->st_elements)) {
+ element = list_entry(entry, struct stack_element, list);
+ retval = stack_io_channel_set_blksize(element->channel,
blksize);
+ if (retval)
+ return retval;
+ }
+
+ channel->block_size = blksize;
+ return retval;
+}
+
+#define list_for_each_prev(pos, head) \
+ for (pos = (head)->prev; pos != (head); \
+ pos = pos->prev)
+
+static errcode_t stack_io_channel_read_blk(io_channel channel,
+ unsigned long block, int count, void *buf)
+{
+ if (channel && channel->manager->read_blk)
+ return channel->manager->read_blk(channel,
+ block, count, buf);
+
+ return 0;
+}
+static errcode_t stack_read_blk(io_channel channel, unsigned long block,
+ int count, void *buf)
+{
+ struct stack_private_data *data;
+ struct list_head *entry;
+ struct stack_element *element;
+ errcode_t retval = 0;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct stack_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_STACK_IO_CHANNEL);
+
+ /*
+ * we should read int the reverse order
+ */
+ list_for_each_prev(entry, &(data->st_elements)) {
+ element = list_entry(entry, struct stack_element, list);
+ retval = stack_io_channel_read_blk(element->channel, block,
count, buf);
+ if (retval)
+ return retval;
+ }
+
+ return retval;
+}
+
+static errcode_t stack_io_channel_write_blk(io_channel channel,
+ unsigned long block, int count, const void *buf)
+{
+ if (channel && channel->manager->write_blk)
+ return channel->manager->write_blk(channel,
+ block, count, buf);
+
+ return 0;
+}
+static errcode_t stack_write_blk(io_channel channel, unsigned long block,
+ int count, const void *buf)
+{
+ struct stack_private_data *data;
+ struct list_head *entry;
+ struct stack_element *element;
+ errcode_t retval = 0;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct stack_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_STACK_IO_CHANNEL);
+
+ list_for_each(entry, &(data->st_elements)) {
+ element = list_entry(entry, struct stack_element, list);
+ retval = stack_io_channel_write_blk(element->channel, block,
count, buf);
+ if (retval)
+ return retval;
+ }
+
+ return retval;
+}
+
+static errcode_t stack_io_channel_write_byte(io_channel channel,
+ unsigned long offset, int count, const void *buf)
+{
+ if (channel && channel->manager->write_byte)
+ return channel->manager->write_byte(channel,
+ offset, count, buf);
+
+ return 0;
+}
+
+static errcode_t stack_write_byte(io_channel channel, unsigned long offset,
+ int count, const void *buf)
+{
+ struct stack_private_data *data;
+ struct list_head *entry;
+ struct stack_element *element;
+ errcode_t retval = 0;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct stack_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_STACK_IO_CHANNEL);
+
+ list_for_each(entry, &(data->st_elements)) {
+ element = list_entry(entry, struct stack_element, list);
+ retval = stack_io_channel_write_byte(element->channel, offset,
count, buf);
+ if (retval)
+ return retval;
+ }
+
+ return retval;
+}
+
+static errcode_t stack_io_channel_flush(io_channel channel)
+{
+ if (channel && channel->manager->flush)
+ return channel->manager->flush(channel);
+
+ return 0;
+
+}
+
+/*
+ * Flush data buffers to disk.
+ */
+static errcode_t stack_flush(io_channel channel)
+{
+ struct stack_private_data *data;
+ struct list_head *entry;
+ struct stack_element *element;
+ errcode_t retval = 0;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct stack_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_STACK_IO_CHANNEL);
+
+ list_for_each(entry, &(data->st_elements)) {
+ element = list_entry(entry, struct stack_element, list);
+ retval = stack_io_channel_flush(element->channel);
+ if (retval)
+ return retval;
+ }
+
+ return retval;
+}
+
+
+static errcode_t stack_io_channel_set_option(io_channel channel,
+ const char *option, const char *arg)
+{
+ if (channel && channel->manager->set_option)
+ return channel->manager->set_option(channel,
+ option, arg);
+
+ return 0;
+
+}
+static errcode_t stack_set_option(io_channel channel, const char *option,
+ const char *arg)
+{
+ struct stack_private_data *data;
+ struct list_head *entry;
+ struct stack_element *element;
+ errcode_t retval = 0;
+ struct struct_io_manager *io_mng;
+ int success;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct stack_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_STACK_IO_CHANNEL);
+
+ list_for_each(entry, &(data->st_elements)) {
+ element = list_entry(entry, struct stack_element, list);
+ retval = stack_io_channel_set_option(element->channel,
+ option, arg);
+ if (retval == 0) {
+ success = 1;
+ continue;
+ }
+
+ if (retval == EXT2_ET_INVALID_ARGUMENT) {
+ /*
+ * this may be the option for some other io manager
+ * if everybody said EXT2_ET_INVALID_ARGUMENT
+ * then we will return that
+ */
+ continue;
+ } else {
+ return retval;
+ }
+ }
+
+ if (success)
+ return 0;
+
+ return retval;
+}
--
1.5.2.rc0.71.g4342-dirty
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