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