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.
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| @@ -305,6 +305,31 @@ struct btrfs_ioctl_clone_range_args { · 304 unmodified lines | |||
| 305 | #define BTRFS_DEFRAG_RANGE_COMPRESS 1 | 305 | #define BTRFS_DEFRAG_RANGE_COMPRESS 1 |
| 306 | #define BTRFS_DEFRAG_RANGE_START_IO 2 | 306 | #define BTRFS_DEFRAG_RANGE_START_IO 2 |
| 307 | 307 | ||
| 308 | #define BTRFS_SAME_DATA_DIFFERS 1 | ||
| 309 | /* For extent-same ioctl */ | ||
| 310 | struct btrfs_ioctl_same_extent_info { | ||
| 311 | __s64 fd; /* in - destination file */ | ||
| 312 | __u64 logical_offset; /* in - start of extent in destination */ | ||
| 313 | __u64 bytes_deduped; /* out - total # of bytes we were able | ||
| 314 | * to dedupe from this file */ | ||
| 315 | /* status of this dedupe operation: | ||
| 316 | * 0 if dedup succeeds | ||
| 317 | * < 0 for error | ||
| 318 | * == BTRFS_SAME_DATA_DIFFERS if data differs | ||
| 319 | */ | ||
| 320 | __s32 status; /* out - see above description */ | ||
| 321 | __u32 reserved; | ||
| 322 | }; | ||
| 323 | |||
| 324 | struct btrfs_ioctl_same_args { | ||
| 325 | __u64 logical_offset; /* in - start of extent in source */ | ||
| 326 | __u64 length; /* in - length of extent */ | ||
| 327 | __u16 dest_count; /* in - total elements in info array */ | ||
| 328 | __u16 reserved1; | ||
| 329 | __u32 reserved2; | ||
| 330 | struct btrfs_ioctl_same_extent_info info[0]; | ||
| 331 | }; | ||
| 332 | |||
| 308 | struct btrfs_ioctl_space_info { | 333 | struct btrfs_ioctl_space_info { |
| 309 | __u64 flags; | 334 | __u64 flags; |
| 310 | __u64 total_bytes; | 335 | __u64 total_bytes; |
| @@ -579,4 +604,7 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code) · 268 unmodified lines | |||
| 579 | struct btrfs_ioctl_get_dev_stats) | 604 | struct btrfs_ioctl_get_dev_stats) |
| 580 | #define BTRFS_IOC_DEV_REPLACE _IOWR(BTRFS_IOCTL_MAGIC, 53, \ | 605 | #define BTRFS_IOC_DEV_REPLACE _IOWR(BTRFS_IOCTL_MAGIC, 53, \ |
| 581 | struct btrfs_ioctl_dev_replace_args) | 606 | struct btrfs_ioctl_dev_replace_args) |
| 607 | #define BTRFS_IOC_FILE_EXTENT_SAME _IOWR(BTRFS_IOCTL_MAGIC, 54, \ | ||
| 608 | struct btrfs_ioctl_same_args) | ||
| 609 | |||
| 582 | #endif /* _UAPI_LINUX_BTRFS_H */ | 610 | #endif /* _UAPI_LINUX_BTRFS_H */ |