| Value | Meaning |
|---|---|
| FALLOC_FL_KEEP_SIZE0x01 | Allocates and initializes to zero the disk space within the specified range, but the file size will not be modified. |
| FALLOC_FL_PUNCH_HOLE0x02 | Deallocates space (i.e. creates a hole) |
| FALLOC_FL_NO_HIDE_STALE0x04 | Newly allocated blocks will be marked as initialized. |
| FALLOC_FL_COLLAPSE_RANGE0x08 | Removes a byte range from a file, without leaving a hole |
| FALLOC_FL_ZERO_RANGE0x10 | Zeroes space in the specified byte range |
| FALLOC_FL_INSERT_RANGE0x20 | Increases the file space by inserting a hole without overwriting any existing data |
| FALLOC_FL_UNSHARE_RANGE0x40 | Used to unshare shared blocks within the file size without overwriting any existing data |
fallocate(2) params