diff options
Diffstat (limited to 'include/uapi/linux/falloc.h')
| -rw-r--r-- | include/uapi/linux/falloc.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/include/uapi/linux/falloc.h b/include/uapi/linux/falloc.h index 5810371ed72b..1f9ca757d02d 100644 --- a/include/uapi/linux/falloc.h +++ b/include/uapi/linux/falloc.h @@ -78,4 +78,21 @@ */ #define FALLOC_FL_UNSHARE_RANGE 0x40 +/* + * FALLOC_FL_WRITE_ZEROES zeroes a specified file range in such a way that + * subsequent writes to that range do not require further changes to the file + * mapping metadata. This flag is beneficial for subsequent pure overwriting + * within this range, as it can save on block allocation and, consequently, + * significant metadata changes. Therefore, filesystems that always require + * out-of-place writes should not support this flag. + * + * Different filesystems may implement different limitations on the + * granularity of the zeroing operation. Most will preferably be accelerated + * by submitting write zeroes command if the backing storage supports, which + * may not physically write zeros to the media. + * + * This flag cannot be specified in conjunction with the FALLOC_FL_KEEP_SIZE. + */ +#define FALLOC_FL_WRITE_ZEROES 0x80 + #endif /* _UAPI_FALLOC_H_ */ |