-
-
Save azat/5528380 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| #!/usr/bin/python | |
| import ctypes | |
| import ctypes.util | |
| c_off_t = ctypes.c_int64 | |
| def make_fallocate(): | |
| libc_name = ctypes.util.find_library('c') | |
| libc = ctypes.CDLL(libc_name) | |
| _fallocate = libc.fallocate | |
| _fallocate.restype = ctypes.c_int | |
| _fallocate.argtypes = [ctypes.c_int, ctypes.c_int, c_off_t, c_off_t] | |
| del libc | |
| del libc_name | |
| def fallocate(fd, mode, offset, len_): | |
| res = _fallocate(fd.fileno(), mode, offset, len_) | |
| if res != 0: | |
| raise IOError(res, 'fallocate') | |
| return fallocate | |
| fallocate = make_fallocate() | |
| del make_fallocate | |
| FALLOC_FL_KEEP_SIZE = 0x01 | |
| FALLOC_FL_PUNCH_HOLE = 0x02 | |
| def punch(filename, verbose): | |
| blocksize = 4096 | |
| if verbose: | |
| print "processing", filename | |
| with open(filename, 'r+') as f: | |
| offset = 0 | |
| length = 0 | |
| while True: | |
| buf = f.read(blocksize) | |
| if not buf: | |
| break | |
| for c in buf: | |
| if c != '\x00': | |
| break | |
| else: | |
| if verbose: | |
| print "punching hole at offset", offset, "length", len(buf) | |
| fallocate(f, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, | |
| offset, len(buf)) | |
| offset = offset + blocksize | |
| if __name__ == '__main__': | |
| import sys | |
| import argparse | |
| parser = argparse.ArgumentParser( | |
| description = "Punch out the empty areas in a file, making it sparse") | |
| parser.add_argument('file', metavar='FILE', | |
| help='file(s) to modify in-place', nargs='+') | |
| parser.add_argument('-v', '--verbose', action="store_true", default=False, | |
| help='be verbose') | |
| args = parser.parse_args() | |
| for filename in args.file: | |
| punch(filename, args.verbose) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment