diff options
| -rw-r--r-- | util-linux/fallocate.c | 104 | ||||
| -rw-r--r-- | util-linux/fsfreeze.c | 2 |
2 files changed, 105 insertions, 1 deletions
diff --git a/util-linux/fallocate.c b/util-linux/fallocate.c new file mode 100644 index 0000000..1cd851b --- /dev/null +++ b/util-linux/fallocate.c @@ -0,0 +1,104 @@ +/* vi: set sw=4 ts=4: */ +/* + * Copyright (C) 2017 Denys Vlasenko <vda.linux@googlemail.com> + * + * Licensed under GPLv2, see file LICENSE in this source tree. + */ + +//config:config FALLOCATE +//config: bool "fallocate" +//config: default y +//config: help +//config: Preallocate space for files. + +//applet:IF_FALLOCATE(APPLET(fallocate, BB_DIR_USR_BIN, BB_SUID_DROP)) + +//kbuild:lib-$(CONFIG_FALLOCATE) += fallocate.o + +//usage:#define fallocate_trivial_usage +//usage: "[-o OFS] -l LEN FILE" +// fallocate [-c|-p|-z] [-n] [-o OFS] -l LEN FILE +// fallocate -d [-o OFS] [-l LEN] FILE +//usage:#define fallocate_full_usage "\n\n" +//usage: "Preallocate space for FILE\n" +// "\n -c Remove range" +// "\n -p Make hole" +// "\n -z Zero and allocate range" +// "\n -d Convert zeros to holes" +// "\n -n Keep size" +//usage: "\n -o OFS Offset of range" +//usage: "\n -l LEN Length of range" + +//Upstream options: +//The options --collapse-range, --dig-holes, --punch-hole and --zero-range +//are mutually exclusive. +//-c, --collapse-range +// Removes a byte range from a file, without leaving a hole. The byte range +// to be collapsed starts at offset and continues for length bytes. +// At the completion of the operation, the contents of the file starting +// at the location offset+length will be appended at the location offset, +// and the file will be length bytes smaller. The option --keep-size may +// not be specified for the collapse-range operation. +//-d, --dig-holes +// Detect and dig holes. This makes the file sparse in-place, without using +// extra disk space. The minimum size of the hole depends on filesystem I/O +// block size (usually 4096 bytes). Also, +//-l, --length length +// Specifies the length of the range, in bytes. +//-n, --keep-size +// Do not modify the apparent length of the file. This may effectively +// allocate blocks past EOF, which can be removed with a truncate. +//-o, --offset offset +// Specifies the beginning offset of the range, in bytes. +//-p, --punch-hole +// Deallocates space (i.e., creates a hole) in the byte range starting +// at offset and continuing for length bytes. Within the specified range, +// partial filesystem blocks are zeroed, and whole +// filesystem blocks are removed from the file. After a successful call, +// subsequent reads from this range will return zeroes. This option may not +// be specified at the same time as the +// --zero-range option. Also, when using this option, --keep-size is implied. +//-z, --zero-range +// Zeroes space in the byte range starting at offset and continuing for +// length bytes. Within the specified range, blocks are preallocated for +// the regions that span the holes in the file. After +// a successful call, subsequent reads from this range will return zeroes. +// Zeroing is done within the filesystem preferably by converting the range +// into unwritten extents. This approach means that the specified range +// will not be physically zeroed out on the device (except for partial +// blocks at the either end of the range), and I/O is (otherwise) required +// only to update metadata. +// Option --keep-size can be specified to prevent file length modification. + +#include "libbb.h" + +int fallocate_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; +int fallocate_main(int argc UNUSED_PARAM, char **argv) +{ + const char *str_l; + const char *str_o = "0"; + off_t ofs, len; + unsigned opts; + int fd; + + /* exactly one non-option arg */ + opt_complementary = "=1"; + opts = getopt32(argv, "l:o:", &str_l, &str_o); + if (!(opts & 1)) + bb_show_usage(); + + ofs = xatoull_sfx(str_o, kmg_i_suffixes); + len = xatoull_sfx(str_l, kmg_i_suffixes); + + argv += optind; + fd = xopen3(*argv, O_RDWR | O_CREAT, 0666); + + /* posix_fallocate has unusual method of returning error */ + /* maybe use Linux-specific fallocate(int fd, int mode, off_t offset, off_t len) instead? */ + if ((errno = posix_fallocate(fd, ofs, len)) != 0) + bb_perror_msg_and_die("fallocate '%s'", *argv); + + /* util-linux also performs fsync(fd); */ + + return EXIT_SUCCESS; +} diff --git a/util-linux/fsfreeze.c b/util-linux/fsfreeze.c index fb1ebdc..70dec24 100644 --- a/util-linux/fsfreeze.c +++ b/util-linux/fsfreeze.c @@ -13,7 +13,7 @@ //config: help //config: Halt new accesses and flush writes on a mounted filesystem. -//applet:IF_FSFREEZE(APPLET(fsfreeze, BB_DIR_SBIN, BB_SUID_DROP)) +//applet:IF_FSFREEZE(APPLET(fsfreeze, BB_DIR_USR_SBIN, BB_SUID_DROP)) //kbuild:lib-$(CONFIG_FSFREEZE) += fsfreeze.o |