4.14-stable review patch. If anyone has any objections, please let me know.
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From: John Pittman jpittman@redhat.com
[ 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 --- drivers/md/dm-cache-target.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-)
--- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -2330,7 +2330,7 @@ static int parse_features(struct cache_a {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_a 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_a } }
+ if (mode_ctr > 1) { + *error = "Duplicate cache io_mode features requested"; + return -EINVAL; + } + return 0; }