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 | 305 | #define BTRFS_DEFRAG_RANGE_COMPRESS 1 |
| 306 | 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 | 333 | struct btrfs_ioctl_space_info { |
| 309 | 334 | __u64 flags; |
| 310 | 335 | __u64 total_bytes; |
| @@ -579,4 +604,7 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code) · 268 unmodified lines | ||
| 579 | 604 | struct btrfs_ioctl_get_dev_stats) |
| 580 | 605 | #define BTRFS_IOC_DEV_REPLACE _IOWR(BTRFS_IOCTL_MAGIC, 53, \ |
| 581 | 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 | 610 | #endif /* _UAPI_LINUX_BTRFS_H */ |