4.2.8-ckt9 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------
From: Mike Snitzer <snitzer@xxxxxxxxxx>
commit 9567366fefddeaea4ed1d713270535d93a3b3c76 upstream.
The READ_LOCK macro was incorrectly returning -EINVAL if
dm_bm_is_read_only() was true -- it will always be true once the cache
metadata transitions to read-only by dm_cache_metadata_set_read_only().
Wrap READ_LOCK and WRITE_LOCK multi-statement macros in do {} while(0).
Also, all accesses of the 'cmd' argument passed to these related macros
are now encapsulated in parenthesis.
A follow-up patch can be developed to eliminate the use of macros in
favor of pure C code. Avoiding that now given that this needs to apply
to stable@.
Reported-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Fixes: d14fcf3dd79 ("dm cache: make sure every metadata function checks fail_io")
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
drivers/md/dm-cache-metadata.c | 64 ++++++++++++++++++++++++++----------------
1 file changed, 40 insertions(+), 24 deletions(-)
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
index 1ed4ab1..141b9bc 100644
--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -863,39 +863,55 @@ static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
return 0;
}
-#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; \
+static bool cmd_write_lock(struct dm_cache_metadata *cmd)
+{
+ down_write(&cmd->root_lock);
+ if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
+ up_write(&cmd->root_lock);
+ return false;
}
+ return true;
+}
-#define WRITE_LOCK_VOID(cmd) \
- down_write(&cmd->root_lock); \
- if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \
- up_write(&cmd->root_lock); \
- return; \
- }
+#define WRITE_LOCK(cmd) \
+ do { \
+ if (!cmd_write_lock((cmd))) \
+ return -EINVAL; \
+ } while(0)
+
+#define WRITE_LOCK_VOID(cmd) \
+ do { \
+ if (!cmd_write_lock((cmd))) \
+ return; \
+ } while(0)
#define WRITE_UNLOCK(cmd) \
- up_write(&cmd->root_lock)
+ 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; \
+static bool cmd_read_lock(struct dm_cache_metadata *cmd)
+{
+ down_write(&cmd->root_lock);
+ if (cmd->fail_io) {
+ up_write(&cmd->root_lock);
+ return false;
}
+ return true;
+}
-#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_LOCK(cmd) \
+ do { \
+ if (!cmd_read_lock((cmd))) \
+ return -EINVAL; \
+ } while(0)
+
+#define READ_LOCK_VOID(cmd) \
+ do { \
+ if (!cmd_read_lock((cmd))) \
+ return; \
+ } while(0)
#define READ_UNLOCK(cmd) \
- up_read(&cmd->root_lock)
+ up_read(&(cmd)->root_lock)
int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
{
--
2.7.4
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