ext4: online defrag -- Add EXT4_IOC_MOVE_EXT ioctl

The EXT4_IOC_MOVE_EXT exchanges the blocks between orig_fd and donor_fd,
and then write the file data of orig_fd to donor_fd.
ext4_mext_move_extent() is the main fucntion of ext4 online defrag,
and this patch includes all functions related to ext4 online defrag.

Signed-off-by: Akira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: Takashi Sato <t-sato@yk.jp.nec.com>
Signed-off-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 15 insertions, 0 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index cc7d5edc38c9..276a26f117e6 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -352,6 +352,7 @@ struct ext4_new_group_data {
  /* note ioctl 10 reserved for an early version of the FIEMAP ioctl */
  /* note ioctl 11 reserved for filesystem-independent FIEMAP ioctl */
 #define EXT4_IOC_ALLOC_DA_BLKS          _IO('f', 12)
+#define EXT4_IOC_MOVE_EXT               _IOWR('f', 15, struct move_extent)
 
 /*
  * ioctl commands in 32 bit emulation
@@ -447,6 +448,15 @@ struct ext4_inode {
         __le32  i_version_hi;   /* high 32 bits for 64-bit version */
 };
 
+struct move_extent {
+        __u32 reserved;         /* should be zero */
+        __u32 donor_fd;         /* donor file descriptor */
+        __u64 orig_start;       /* logical start offset in block for orig */
+        __u64 donor_start;      /* logical start offset in block for donor */
+        __u64 len;              /* block length to be moved */
+        __u64 moved_len;        /* moved block length */
+};
+#define MAX_DEFRAG_SIZE         ((1UL<<31) - 1)
 
 #define EXT4_EPOCH_BITS 2
 #define EXT4_EPOCH_MASK ((1 << EXT4_EPOCH_BITS) - 1)
@@ -1647,6 +1657,11 @@ extern int ext4_get_blocks(handle_t *handle, struct inode *inode,
                            struct buffer_head *bh, int flags);
 extern int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
                         __u64 start, __u64 len);
+/* move_extent.c */
+extern int ext4_move_extents(struct file *o_filp, struct file *d_filp,
+                             __u64 start_orig, __u64 start_donor,
+                             __u64 len, __u64 *moved_len);
+
 
 /*
  * Add new method to test wether block and inode bitmaps are properly