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dm cache: only allow a single io_mode cache feature to be requested

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[ Upstream commit af9313c32c0fa2a0ac3b113669273833d60cc9de ]

More than one io_mode feature can be requested when creating a dm cache
device (as is: last one wins).  The io_mode selections are incompatible
with one another, we should force them to be selected exclusively.  Add
a counter to check for more than one io_mode selection.

Fixes: 629d0a8a1a10 ("dm cache metadata: add "metadata2" feature")
Signed-off-by: John Pittman <jpittman@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
John Pittman 2018-06-21 17:35:33 -04:00 committed by Greg Kroah-Hartman
parent 94f885db2a
commit e85940a5bb
1 changed files with 15 additions and 4 deletions
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19
drivers/md/dm-cache-target.c
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@ -2330,7 +2330,7 @@ static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
{0, 2, "Invalid number of cache feature arguments"},
};
int r;
int r, mode_ctr = 0;
unsigned argc;
const char *arg;
struct cache_features *cf = &ca->features;
@ -2344,14 +2344,20 @@ static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
while (argc--) {
arg = dm_shift_arg(as);
if (!strcasecmp(arg, "writeback"))
if (!strcasecmp(arg, "writeback")) {
cf->io_mode = CM_IO_WRITEBACK;
mode_ctr++;
}
else if (!strcasecmp(arg, "writethrough"))
else if (!strcasecmp(arg, "writethrough")) {
cf->io_mode = CM_IO_WRITETHROUGH;
mode_ctr++;
}
else if (!strcasecmp(arg, "passthrough"))
else if (!strcasecmp(arg, "passthrough")) {
cf->io_mode = CM_IO_PASSTHROUGH;
mode_ctr++;
}
else if (!strcasecmp(arg, "metadata2"))
cf->metadata_version = 2;
@ -2362,6 +2368,11 @@ static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
}
}
if (mode_ctr > 1) {
*error = "Duplicate cache io_mode features requested";
return -EINVAL;
}
return 0;
}