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author | Dr. Tilmann Bubeck <t.bubeck@reinform.de> | 2013-04-08 12:54:05 -0400 |
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committer | Theodore Ts'o <tytso@mit.edu> | 2013-04-08 12:54:05 -0400 |
commit | 393d1d1d76933886d5e1ce603214c9987589c6d5 (patch) | |
tree | 2f2368a9d787ccb8e69f61a3e5023ef9c4abfd8b /fs/btrfs/delayed-ref.h | |
parent | f78ee70db40040e6f38a5134527d4760254d6683 (diff) |
ext4: implementation of a new ioctl called EXT4_IOC_SWAP_BOOT
Add a new ioctl, EXT4_IOC_SWAP_BOOT which swaps i_blocks and
associated attributes (like i_blocks, i_size, i_flags, ...) from the
specified inode with inode EXT4_BOOT_LOADER_INO (#5). This is
typically used to store a boot loader in a secure part of the
filesystem, where it can't be changed by a normal user by accident.
The data blocks of the previous boot loader will be associated with
the given inode.
This usercode program is a simple example of the usage:
int main(int argc, char *argv[])
{
int fd;
int err;
if ( argc != 2 ) {
printf("usage: ext4-swap-boot-inode FILE-TO-SWAP\n");
exit(1);
}
fd = open(argv[1], O_WRONLY);
if ( fd < 0 ) {
perror("open");
exit(1);
}
err = ioctl(fd, EXT4_IOC_SWAP_BOOT);
if ( err < 0 ) {
perror("ioctl");
exit(1);
}
close(fd);
exit(0);
}
[ Modified by Theodore Ts'o to fix a number of bugs in the original code.]
Signed-off-by: Dr. Tilmann Bubeck <t.bubeck@reinform.de>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/btrfs/delayed-ref.h')
0 files changed, 0 insertions, 0 deletions