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Date: Wed, 23 Apr 2008 15:39:15 -0400
From: Josef Bacik <jbacik@...hat.com>
To: linux-ext4@...r.kernel.org
Cc: adilger@....com, sandeen@...hat.com
Subject: [PATCH] fiemap support for ext3
Hello,
Here is my reworked fiemap patch for ext3. The generic fiemap handler takes the
get_block_t from the filesystem and does the fiemap that way, so then adding
ext2 support should be a snap, as well as any other fs that wants to use this.
Thanks much,
Signed-off-by: Josef Bacik <jbacik@...hat.com>
Index: linux-2.6.25/fs/ext3/file.c
===================================================================
--- linux-2.6.25.orig/fs/ext3/file.c
+++ linux-2.6.25/fs/ext3/file.c
@@ -134,5 +134,6 @@ const struct inode_operations ext3_file_
.removexattr = generic_removexattr,
#endif
.permission = ext3_permission,
+ .fiemap = ext3_fiemap,
};
Index: linux-2.6.25/fs/ext3/inode.c
===================================================================
--- linux-2.6.25.orig/fs/ext3/inode.c
+++ linux-2.6.25/fs/ext3/inode.c
@@ -36,6 +36,7 @@
#include <linux/mpage.h>
#include <linux/uio.h>
#include <linux/bio.h>
+#include <linux/fiemap.h>
#include "xattr.h"
#include "acl.h"
@@ -981,6 +982,11 @@ out:
return ret;
}
+int ext3_fiemap(struct inode *inode, unsigned long arg)
+{
+ return generic_block_fiemap(inode, arg, ext3_get_block);
+}
+
/*
* `handle' can be NULL if create is zero
*/
Index: linux-2.6.25/include/linux/ext3_fs.h
===================================================================
--- linux-2.6.25.orig/include/linux/ext3_fs.h
+++ linux-2.6.25/include/linux/ext3_fs.h
@@ -836,6 +836,7 @@ extern void ext3_truncate (struct inode
extern void ext3_set_inode_flags(struct inode *);
extern void ext3_get_inode_flags(struct ext3_inode_info *);
extern void ext3_set_aops(struct inode *inode);
+extern int ext3_fiemap(struct inode *inode, unsigned long arg);
/* ioctl.c */
extern int ext3_ioctl (struct inode *, struct file *, unsigned int,
Index: linux-2.6.25/fs/ioctl.c
===================================================================
--- linux-2.6.25.orig/fs/ioctl.c
+++ linux-2.6.25/fs/ioctl.c
@@ -13,6 +13,8 @@
#include <linux/security.h>
#include <linux/module.h>
#include <linux/uaccess.h>
+#include <linux/writeback.h>
+#include <linux/buffer_head.h>
#include <asm/ioctls.h>
@@ -99,6 +101,166 @@ static int ioctl_fiemap(struct file *fil
return error;
}
+int generic_block_fiemap(struct inode *inode, unsigned long arg,
+ get_block_t *get_block)
+{
+ struct fiemap *fiemap_s;
+ struct fiemap_extent fiemap_e;
+ struct buffer_head tmp;
+ unsigned int start_blk;
+ unsigned int num_of_extents;
+ long length;
+ char *cur_ext_ptr = (char *)(arg + sizeof(struct fiemap));
+ int ret, hole = 0;
+
+ fiemap_s = kmalloc(sizeof(struct fiemap), GFP_KERNEL);
+ if (!fiemap_s)
+ return -ENOMEM;
+
+ if (copy_from_user(fiemap_s, (struct fiemap __user *)arg,
+ sizeof(struct fiemap))) {
+ ret = -EFAULT;
+ goto out_free;
+ }
+
+ /*
+ * if fm_start is in the middle of the current block, get the next
+ * block so we don't end up returning a start thats before the given
+ * fm_start
+ */
+ start_blk = (fiemap_s->fm_start + (1 << inode->i_blkbits) - 1) >>
+ inode->i_blkbits;
+ num_of_extents = fiemap_s->fm_extent_count;
+
+ if (fiemap_s->fm_flags & FIEMAP_FLAG_SYNC) {
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_ALL,
+ .nr_to_write = 0,
+ };
+ ret = sync_inode(inode, &wbc);
+ if (ret)
+ goto out_free;
+ }
+
+ /* guard against change */
+ mutex_lock(&inode->i_mutex);
+
+ /*
+ * we want the comparisons to be unsigned, in case somebody passes -1,
+ * meaning they want they want the entire file, but the result has to be
+ * signed so we can handle the case where we get more blocks than the
+ * size of the file
+ */
+ length = (long)min((unsigned long)fiemap_s->fm_length,
+ (unsigned long)i_size_read(inode));
+
+ fiemap_s->fm_start = start_blk << inode->i_blkbits;
+ fiemap_s->fm_length = 0;
+
+ memset(&fiemap_e, 0, sizeof(struct fiemap_extent));
+ do {
+ /*
+ * we set this to length because we want ext3_get_block to
+ * find as many contiguous blocks as it can
+ */
+ memset(&tmp, 0, sizeof(struct buffer_head));
+ tmp.b_size = length;
+
+ ret = get_block(inode, start_blk, &tmp, 0);
+ if (ret)
+ break;
+
+ /*
+ * Hole, we're going to have to walk the inodes blocks until
+ * find data
+ */
+ if (!tmp.b_blocknr) {
+
+ if (!hole) {
+ hole = 1;
+ fiemap_e.fe_flags |= FIEMAP_EXTENT_HOLE;
+ fiemap_e.fe_offset = start_blk <<
+ inode->i_blkbits;
+ }
+
+ fiemap_e.fe_length += 1 << inode->i_blkbits;
+ length -= 1 << inode->i_blkbits;
+ start_blk++;
+ } else {
+ if (hole &&
+ !copy_to_user(cur_ext_ptr, &fiemap_e,
+ sizeof(struct fiemap_extent))) {
+ cur_ext_ptr += sizeof(struct fiemap_extent);
+ fiemap_s->fm_extent_count++;
+ fiemap_s->fm_length += fiemap_e.fe_length;
+
+ hole = 0;
+ num_of_extents--;
+ memset(&fiemap_e, 0,
+ sizeof(struct fiemap_extent));
+
+ if (!num_of_extents || length <= 0)
+ break;
+ } else if (hole) {
+ /* copy_to_user failed */
+ ret = -EFAULT;
+ break;
+ }
+
+ length -= tmp.b_size;
+ start_blk += tmp.b_size >> inode->i_blkbits;
+
+ fiemap_e.fe_offset = tmp.b_blocknr <<
+ inode->i_blkbits;
+ fiemap_e.fe_length = tmp.b_size;
+
+ if (length <= 0)
+ fiemap_e.fe_flags |= FIEMAP_EXTENT_LAST;
+
+ if (!copy_to_user(cur_ext_ptr, &fiemap_e,
+ sizeof(struct fiemap_extent))) {
+ cur_ext_ptr += sizeof(struct fiemap_extent);
+ num_of_extents--;
+ } else {
+ ret = -EFAULT;
+ break;
+ }
+
+ fiemap_s->fm_extent_count++;
+ fiemap_s->fm_length += fiemap_e.fe_length;
+
+ memset(&fiemap_e, 0, sizeof(struct fiemap_extent));
+ }
+ } while (length > 0 && num_of_extents);
+
+ mutex_unlock(&inode->i_mutex);
+
+ /* hole at the end of the file */
+ if (hole && !copy_to_user(cur_ext_ptr, &fiemap_e,
+ sizeof(struct fiemap_extent))) {
+ fiemap_s->fm_extent_count++;
+ fiemap_s->fm_length += fiemap_e.fe_length;
+
+ if (length <= 0)
+ fiemap_e.fe_flags |= FIEMAP_EXTENT_LAST;
+
+ } else if (hole) {
+ /* copy to user failed */
+ ret = -EFAULT;
+ }
+
+ if (!ret) {
+ if (copy_to_user((char *)arg, fiemap_s,
+ sizeof(struct fiemap)))
+ ret = -EFAULT;
+ }
+
+out_free:
+ kfree(fiemap_s);
+ return ret;
+}
+EXPORT_SYMBOL(generic_block_fiemap);
+
static int file_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
{
Index: linux-2.6.25/include/linux/fs.h
===================================================================
--- linux-2.6.25.orig/include/linux/fs.h
+++ linux-2.6.25/include/linux/fs.h
@@ -1925,6 +1925,8 @@ extern int vfs_fstat(unsigned int, struc
extern long vfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
extern int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
unsigned long arg);
+extern int generic_block_fiemap(struct inode *inode, unsigned long arg,
+ get_block_t *get_block);
extern void get_filesystem(struct file_system_type *fs);
extern void put_filesystem(struct file_system_type *fs);
--
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