dm-flakey returns error on reads if no other argument is specified. We
simplify the logic, introduce an "error_reads" argument and an ERROR_READS
flag.
If no argument is specified, we set ERROR_READS, so that it behaves just
like before this patch.
Signed-off-by: Mikulas Patocka <mpato...@redhat.com>
---
Documentation/admin-guide/device-mapper/dm-flakey.rst | 4 +
drivers/md/dm-flakey.c | 39 ++++++++++++------
2 files changed, 31 insertions(+), 12 deletions(-)
Index: linux-2.6/Documentation/admin-guide/device-mapper/dm-flakey.rst
===================================================================
--- linux-2.6.orig/Documentation/admin-guide/device-mapper/dm-flakey.rst
+++ linux-2.6/Documentation/admin-guide/device-mapper/dm-flakey.rst
@@ -39,6 +39,10 @@ Optional feature parameters:
If no feature parameters are present, during the periods of
unreliability, all I/O returns errors.
+ error_reads:
+ All read I/O is failed with an error signalled.
+ Write I/O is handled correctly.
+
drop_writes:
All write I/O is silently ignored.
Read I/O is handled correctly.
Index: linux-2.6/drivers/md/dm-flakey.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-flakey.c
+++ linux-2.6/drivers/md/dm-flakey.c
@@ -37,6 +37,7 @@ struct flakey_c {
};
enum feature_flag_bits {
+ ERROR_READS,
DROP_WRITES,
ERROR_WRITES
};
@@ -53,7 +54,7 @@ static int parse_features(struct dm_arg_
const char *arg_name;
static const struct dm_arg _args[] = {
- {0, 6, "Invalid number of feature args"},
+ {0, 7, "Invalid number of feature args"},
{1, UINT_MAX, "Invalid corrupt bio byte"},
{0, 255, "Invalid corrupt value to write into bio byte
(0-255)"},
{0, UINT_MAX, "Invalid corrupt bio flags mask"},
@@ -77,6 +78,17 @@ static int parse_features(struct dm_arg_
}
/*
+ * error_reads
+ */
+ if (!strcasecmp(arg_name, "error_reads")) {
+ if (test_and_set_bit(ERROR_READS, &fc->flags)) {
+ ti->error = "Feature error_reads duplicated";
+ return -EINVAL;
+ }
+ continue;
+ }
+
+ /*
* drop_writes
*/
if (!strcasecmp(arg_name, "drop_writes")) {
@@ -171,6 +183,12 @@ static int parse_features(struct dm_arg_
return -EINVAL;
}
+ if (!fc->corrupt_bio_byte && !test_bit(ERROR_READS, &fc->flags) &&
+ !test_bit(DROP_WRITES, &fc->flags) && !test_bit(ERROR_WRITES,
&fc->flags)) {
+ set_bit(ERROR_WRITES, &fc->flags);
+ set_bit(ERROR_READS, &fc->flags);
+ }
+
return 0;
}
@@ -346,8 +364,7 @@ static int flakey_map(struct dm_target *
* Otherwise, flakey_end_io() will decide if the reads should
be modified.
*/
if (bio_data_dir(bio) == READ) {
- if (!fc->corrupt_bio_byte && !test_bit(DROP_WRITES,
&fc->flags) &&
- !test_bit(ERROR_WRITES, &fc->flags))
+ if (test_bit(ERROR_READS, &fc->flags))
return DM_MAPIO_KILL;
goto map_bio;
}
@@ -373,11 +390,6 @@ static int flakey_map(struct dm_target *
}
goto map_bio;
}
-
- /*
- * By default, error all I/O.
- */
- return DM_MAPIO_KILL;
}
map_bio:
@@ -404,8 +416,8 @@ static int flakey_end_io(struct dm_targe
*/
corrupt_bio_data(bio, fc);
}
- } else if (!test_bit(DROP_WRITES, &fc->flags) &&
- !test_bit(ERROR_WRITES, &fc->flags)) {
+ }
+ if (test_bit(ERROR_READS, &fc->flags)) {
/*
* Error read during the down_interval if drop_writes
* and error_writes were not configured.
@@ -422,7 +434,7 @@ static void flakey_status(struct dm_targ
{
unsigned int sz = 0;
struct flakey_c *fc = ti->private;
- unsigned int drop_writes, error_writes;
+ unsigned int error_reads, drop_writes, error_writes;
switch (type) {
case STATUSTYPE_INFO:
@@ -434,10 +446,13 @@ static void flakey_status(struct dm_targ
(unsigned long long)fc->start, fc->up_interval,
fc->down_interval);
+ error_reads = test_bit(ERROR_READS, &fc->flags);
drop_writes = test_bit(DROP_WRITES, &fc->flags);
error_writes = test_bit(ERROR_WRITES, &fc->flags);
- DMEMIT(" %u", drop_writes + error_writes +
(fc->corrupt_bio_byte > 0) * 5);
+ DMEMIT(" %u", error_reads + drop_writes + error_writes +
(fc->corrupt_bio_byte > 0) * 5);
+ if (error_reads)
+ DMEMIT(" error_reads");
if (drop_writes)
DMEMIT(" drop_writes");
else if (error_writes)
--
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