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author | Richard W.M. Jones <rjones@redhat.com> | 2021-05-12 17:18:48 +0100 |
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committer | Miklos Szeredi <mszeredi@redhat.com> | 2021-06-22 09:15:36 +0200 |
commit | 6b1bdb56b17c25f640261f3b18030cb0a21d7878 (patch) | |
tree | 189d4777fac7cbce17e8acad2c6409ad0b5af326 /fs/fuse/dir.c | |
parent | 1b539917374d26fb64395eeb5d4baebd7ad38f61 (diff) | |
download | linux-6b1bdb56b17c25f640261f3b18030cb0a21d7878.tar.bz2 |
fuse: allow fallocate(FALLOC_FL_ZERO_RANGE)
The current fuse module filters out fallocate(FALLOC_FL_ZERO_RANGE)
returning -EOPNOTSUPP. libnbd's nbdfuse would like to translate
FALLOC_FL_ZERO_RANGE requests into the NBD command
NBD_CMD_WRITE_ZEROES which allows NBD servers that support it to do
zeroing efficiently.
This commit treats this flag exactly like FALLOC_FL_PUNCH_HOLE.
A way to test this, requiring fuse >= 3, nbdkit >= 1.8 and the latest
nbdfuse from https://gitlab.com/nbdkit/libnbd/-/tree/master/fuse is to
create a file containing some data and "mirror" it to a fuse file:
$ dd if=/dev/urandom of=disk.img bs=1M count=1
$ nbdkit file disk.img
$ touch mirror.img
$ nbdfuse mirror.img nbd://localhost &
(mirror.img -> nbdfuse -> NBD over loopback -> nbdkit -> disk.img)
You can then run commands such as:
$ fallocate -z -o 1024 -l 1024 mirror.img
and check that the content of the original file ("disk.img") stays
synchronized. To show NBD commands, export LIBNBD_DEBUG=1 before
running nbdfuse. To clean up:
$ fusermount3 -u mirror.img
$ killall nbdkit
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/fuse/dir.c')
0 files changed, 0 insertions, 0 deletions