From 416161db9b63e353a8fb79d1369779175102fca1 Mon Sep 17 00:00:00 2001 From: Mark Fasheh Date: Tue, 6 Aug 2013 11:42:51 -0700 Subject: btrfs: offline dedupe This patch adds an ioctl, BTRFS_IOC_FILE_EXTENT_SAME which will try to de-duplicate a list of extents across a range of files. Internally, the ioctl re-uses code from the clone ioctl. This avoids rewriting a large chunk of extent handling code. Userspace passes in an array of file, offset pairs along with a length argument. The ioctl will then (for each dedupe) do a byte-by-byte comparison of the user data before deduping the extent. Status and number of bytes deduped are returned for each operation. Signed-off-by: Mark Fasheh Reviewed-by: Zach Brown Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- include/uapi/linux/btrfs.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'include') diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index 05aed70627e2..90d7bd9d839c 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -305,6 +305,31 @@ struct btrfs_ioctl_clone_range_args { #define BTRFS_DEFRAG_RANGE_COMPRESS 1 #define BTRFS_DEFRAG_RANGE_START_IO 2 +#define BTRFS_SAME_DATA_DIFFERS 1 +/* For extent-same ioctl */ +struct btrfs_ioctl_same_extent_info { + __s64 fd; /* in - destination file */ + __u64 logical_offset; /* in - start of extent in destination */ + __u64 bytes_deduped; /* out - total # of bytes we were able + * to dedupe from this file */ + /* status of this dedupe operation: + * 0 if dedup succeeds + * < 0 for error + * == BTRFS_SAME_DATA_DIFFERS if data differs + */ + __s32 status; /* out - see above description */ + __u32 reserved; +}; + +struct btrfs_ioctl_same_args { + __u64 logical_offset; /* in - start of extent in source */ + __u64 length; /* in - length of extent */ + __u16 dest_count; /* in - total elements in info array */ + __u16 reserved1; + __u32 reserved2; + struct btrfs_ioctl_same_extent_info info[0]; +}; + struct btrfs_ioctl_space_info { __u64 flags; __u64 total_bytes; @@ -579,4 +604,7 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code) struct btrfs_ioctl_get_dev_stats) #define BTRFS_IOC_DEV_REPLACE _IOWR(BTRFS_IOCTL_MAGIC, 53, \ struct btrfs_ioctl_dev_replace_args) +#define BTRFS_IOC_FILE_EXTENT_SAME _IOWR(BTRFS_IOCTL_MAGIC, 54, \ + struct btrfs_ioctl_same_args) + #endif /* _UAPI_LINUX_BTRFS_H */ -- cgit v1.2.3