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- From 34fed3ff1740aded9c2aae6b5d67a4eb696f738e Mon Sep 17 00:00:00 2001
- From: Karel Zak <kzak@redhat.com>
- Date: Thu, 9 Jan 2020 11:03:51 +0100
- Subject: [PATCH] blkdiscard: use O_EXCL, add --force
- Let's make it more robust and safe. O_EXCL is an elegant way how to avoid
- unwanted discard on mounted device.
- Addresses: https://github.com/karelzak/util-linux/issues/915
- Signed-off-by: Karel Zak <kzak@redhat.com>
- ---
- sys-utils/blkdiscard.8 | 5 +++++
- sys-utils/blkdiscard.c | 11 ++++++++---
- 2 files changed, 13 insertions(+), 3 deletions(-)
- diff --git a/sys-utils/blkdiscard.8 b/sys-utils/blkdiscard.8
- index 1f3a32be9..98c6f36a9 100644
- --- a/sys-utils/blkdiscard.8
- +++ b/sys-utils/blkdiscard.8
- @@ -36,6 +36,11 @@ MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is
- optional, e.g., "K" has the same meaning as "KiB") or the suffixes
- KB (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.
- .TP
- +.BR \-f , " \-\-force"
- +Disable all checking. Since v2.36 the block device is open in exclusive mode (O_EXCL)
- +by default to avoid collision with mounted filesystem or another kernel subsystem.
- +The force option disables the exclusive access mode.
- +.TP
- .BR \-o , " \-\-offset \fIoffset"
- Byte offset into the device from which to start discarding. The provided value
- will be aligned to the device sector size. The default value is zero.
- diff --git a/sys-utils/blkdiscard.c b/sys-utils/blkdiscard.c
- index f9ba5e468..589974f9c 100644
- --- a/sys-utils/blkdiscard.c
- +++ b/sys-utils/blkdiscard.c
- @@ -88,6 +88,7 @@ static void __attribute__((__noreturn__)) usage(void)
- fputs(_("Discard the content of sectors on a device.\n"), out);
-
- fputs(USAGE_OPTIONS, out);
- + fputs(_(" -f, --force disable all checking\n"), out);
- fputs(_(" -o, --offset <num> offset in bytes to discard from\n"), out);
- fputs(_(" -l, --length <num> length of bytes to discard from the offset\n"), out);
- fputs(_(" -p, --step <num> size of the discard iterations within the offset\n"), out);
- @@ -106,7 +107,7 @@ static void __attribute__((__noreturn__)) usage(void)
- int main(int argc, char **argv)
- {
- char *path;
- - int c, fd, verbose = 0, secsize;
- + int c, fd, verbose = 0, secsize, force = 0;
- uint64_t end, blksize, step, range[2], stats[2];
- struct stat sb;
- struct timeval now, last;
- @@ -116,6 +117,7 @@ int main(int argc, char **argv)
- { "help", no_argument, NULL, 'h' },
- { "version", no_argument, NULL, 'V' },
- { "offset", required_argument, NULL, 'o' },
- + { "force", no_argument, NULL, 'f' },
- { "length", required_argument, NULL, 'l' },
- { "step", required_argument, NULL, 'p' },
- { "secure", no_argument, NULL, 's' },
- @@ -133,8 +135,11 @@ int main(int argc, char **argv)
- range[1] = ULLONG_MAX;
- step = 0;
-
- - while ((c = getopt_long(argc, argv, "hVsvo:l:p:z", longopts, NULL)) != -1) {
- + while ((c = getopt_long(argc, argv, "hfVsvo:l:p:z", longopts, NULL)) != -1) {
- switch(c) {
- + case 'f':
- + force = 1;
- + break;
- case 'l':
- range[1] = strtosize_or_err(optarg,
- _("failed to parse length"));
- @@ -176,7 +181,7 @@ int main(int argc, char **argv)
- errtryhelp(EXIT_FAILURE);
- }
-
- - fd = open(path, O_WRONLY);
- + fd = open(path, O_WRONLY | (force ? 0 : O_EXCL));
- if (fd < 0)
- err(EXIT_FAILURE, _("cannot open %s"), path);
-
- --
- 2.18.2
|
