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dm cache: make sure every metadata function checks fail_io
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Otherwise operations may be attempted that will only ever go on to crash
(since the metadata device is either missing or unreliable if 'fail_io'
is set).

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
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@jthornber @snitm
jthornber authored and snitm committed Mar 10, 2016
1 parent 3f06804 commit d14fcf3
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Showing 3 changed files with 71 additions and 43 deletions.
98 changes: 59 additions & 39 deletions drivers/md/dm-cache-metadata.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -867,19 +867,40 @@ static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
return 0;
}

#define WRITE_LOCK(cmd) \
if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) \
#define WRITE_LOCK(cmd) \
down_write(&cmd->root_lock); \
if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \
up_write(&cmd->root_lock); \
return -EINVAL; \
down_write(&cmd->root_lock)
}

#define WRITE_LOCK_VOID(cmd) \
if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) \
down_write(&cmd->root_lock); \
if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \
up_write(&cmd->root_lock); \
return; \
down_write(&cmd->root_lock)
}

#define WRITE_UNLOCK(cmd) \
up_write(&cmd->root_lock)

#define READ_LOCK(cmd) \
down_read(&cmd->root_lock); \
if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \
up_read(&cmd->root_lock); \
return -EINVAL; \
}

#define READ_LOCK_VOID(cmd) \
down_read(&cmd->root_lock); \
if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \
up_read(&cmd->root_lock); \
return; \
}

#define READ_UNLOCK(cmd) \
up_read(&cmd->root_lock)

int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
{
int r;
Expand Down Expand Up @@ -1015,22 +1036,20 @@ int dm_cache_load_discards(struct dm_cache_metadata *cmd,
{
int r;

down_read(&cmd->root_lock);
READ_LOCK(cmd);
r = __load_discards(cmd, fn, context);
up_read(&cmd->root_lock);
READ_UNLOCK(cmd);

return r;
}

dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd)
int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
{
dm_cblock_t r;
READ_LOCK(cmd);
*result = cmd->cache_blocks;
READ_UNLOCK(cmd);

down_read(&cmd->root_lock);
r = cmd->cache_blocks;
up_read(&cmd->root_lock);

return r;
return 0;
}

static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
Expand Down Expand Up @@ -1188,9 +1207,9 @@ int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
{
int r;

down_read(&cmd->root_lock);
READ_LOCK(cmd);
r = __load_mappings(cmd, policy, fn, context);
up_read(&cmd->root_lock);
READ_UNLOCK(cmd);

return r;
}
Expand All @@ -1215,18 +1234,18 @@ static int __dump_mappings(struct dm_cache_metadata *cmd)

void dm_cache_dump(struct dm_cache_metadata *cmd)
{
down_read(&cmd->root_lock);
READ_LOCK_VOID(cmd);
__dump_mappings(cmd);
up_read(&cmd->root_lock);
READ_UNLOCK(cmd);
}

int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
{
int r;

down_read(&cmd->root_lock);
READ_LOCK(cmd);
r = cmd->changed;
up_read(&cmd->root_lock);
READ_UNLOCK(cmd);

return r;
}
Expand Down Expand Up @@ -1276,9 +1295,9 @@ int dm_cache_set_dirty(struct dm_cache_metadata *cmd,
void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
struct dm_cache_statistics *stats)
{
down_read(&cmd->root_lock);
READ_LOCK_VOID(cmd);
*stats = cmd->stats;
up_read(&cmd->root_lock);
READ_UNLOCK(cmd);
}

void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
Expand Down Expand Up @@ -1312,9 +1331,9 @@ int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
{
int r = -EINVAL;

down_read(&cmd->root_lock);
READ_LOCK(cmd);
r = dm_sm_get_nr_free(cmd->metadata_sm, result);
up_read(&cmd->root_lock);
READ_UNLOCK(cmd);

return r;
}
Expand All @@ -1324,9 +1343,9 @@ int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
{
int r = -EINVAL;

down_read(&cmd->root_lock);
READ_LOCK(cmd);
r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
up_read(&cmd->root_lock);
READ_UNLOCK(cmd);

return r;
}
Expand Down Expand Up @@ -1417,7 +1436,13 @@ int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *

int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
{
return blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
int r;

READ_LOCK(cmd);
r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
READ_UNLOCK(cmd);

return r;
}

void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
Expand All @@ -1440,10 +1465,7 @@ int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
struct dm_block *sblock;
struct cache_disk_superblock *disk_super;

/*
* We ignore fail_io for this function.
*/
down_write(&cmd->root_lock);
WRITE_LOCK(cmd);
set_bit(NEEDS_CHECK, &cmd->flags);

r = superblock_lock(cmd, &sblock);
Expand All @@ -1458,19 +1480,17 @@ int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
dm_bm_unlock(sblock);

out:
up_write(&cmd->root_lock);
WRITE_UNLOCK(cmd);
return r;
}

bool dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd)
int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
{
bool needs_check;
READ_LOCK(cmd);
*result = !!test_bit(NEEDS_CHECK, &cmd->flags);
READ_UNLOCK(cmd);

down_read(&cmd->root_lock);
needs_check = !!test_bit(NEEDS_CHECK, &cmd->flags);
up_read(&cmd->root_lock);

return needs_check;
return 0;
}

int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
Expand Down
4 changes: 2 additions & 2 deletions drivers/md/dm-cache-metadata.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -66,7 +66,7 @@ void dm_cache_metadata_close(struct dm_cache_metadata *cmd);
* origin blocks to map to.
*/
int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size);
dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd);
int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result);

int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
sector_t discard_block_size,
Expand Down Expand Up @@ -137,7 +137,7 @@ int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *
*/
int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result);

bool dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd);
int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result);
int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd);
void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd);
void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd);
Expand Down
12 changes: 10 additions & 2 deletions drivers/md/dm-cache-target.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -984,9 +984,14 @@ static void notify_mode_switch(struct cache *cache, enum cache_metadata_mode mod

static void set_cache_mode(struct cache *cache, enum cache_metadata_mode new_mode)
{
bool needs_check = dm_cache_metadata_needs_check(cache->cmd);
bool needs_check;
enum cache_metadata_mode old_mode = get_cache_mode(cache);

if (dm_cache_metadata_needs_check(cache->cmd, &needs_check)) {
DMERR("unable to read needs_check flag, setting failure mode");
new_mode = CM_FAIL;
}

if (new_mode == CM_WRITE && needs_check) {
DMERR("%s: unable to switch cache to write mode until repaired.",
cache_device_name(cache));
Expand Down Expand Up @@ -3510,6 +3515,7 @@ static void cache_status(struct dm_target *ti, status_type_t type,
char buf[BDEVNAME_SIZE];
struct cache *cache = ti->private;
dm_cblock_t residency;
bool needs_check;

switch (type) {
case STATUSTYPE_INFO:
Expand Down Expand Up @@ -3583,7 +3589,9 @@ static void cache_status(struct dm_target *ti, status_type_t type,
else
DMEMIT("rw ");

if (dm_cache_metadata_needs_check(cache->cmd))
r = dm_cache_metadata_needs_check(cache->cmd, &needs_check);

if (r || needs_check)
DMEMIT("needs_check ");
else
DMEMIT("- ");
Expand Down

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