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dm cache metadata: fix READ_LOCK macros and cleanup WRITE_LOCK macros

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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@decadent.org.uk>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Fixes: d14fcf3dd79 ("dm cache: make sure every metadata function checks fail_io")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mike Snitzer 2016-04-12 12:14:46 -04:00 committed by Greg Kroah-Hartman
parent e4c7ab7658
commit 9d58f322ee
1 changed files with 40 additions and 24 deletions
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64
drivers/md/dm-cache-metadata.c
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@ -867,39 +867,55 @@ static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
return 0; return 0;
} }
#define WRITE_LOCK(cmd) \ 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)) { \ down_write(&cmd->root_lock);
up_write(&cmd->root_lock); \ if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
return -EINVAL; \ up_write(&cmd->root_lock);
return false;
} }
return true;
}
#define WRITE_LOCK_VOID(cmd) \ #define WRITE_LOCK(cmd) \
down_write(&cmd->root_lock); \ do { \
if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \ if (!cmd_write_lock((cmd))) \
up_write(&cmd->root_lock); \ return -EINVAL; \
return; \ } while(0)
}
#define WRITE_LOCK_VOID(cmd) \
do { \
if (!cmd_write_lock((cmd))) \
return; \
} while(0)
#define WRITE_UNLOCK(cmd) \ #define WRITE_UNLOCK(cmd) \
up_write(&cmd->root_lock) up_write(&(cmd)->root_lock)
#define READ_LOCK(cmd) \ static bool cmd_read_lock(struct dm_cache_metadata *cmd)
down_read(&cmd->root_lock); \ {
if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \ down_write(&cmd->root_lock);
up_read(&cmd->root_lock); \ if (cmd->fail_io) {
return -EINVAL; \ up_write(&cmd->root_lock);
return false;
} }
return true;
}
#define READ_LOCK_VOID(cmd) \ #define READ_LOCK(cmd) \
down_read(&cmd->root_lock); \ do { \
if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \ if (!cmd_read_lock((cmd))) \
up_read(&cmd->root_lock); \ return -EINVAL; \
return; \ } while(0)
}
#define READ_LOCK_VOID(cmd) \
do { \
if (!cmd_read_lock((cmd))) \
return; \
} while(0)
#define READ_UNLOCK(cmd) \ #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) int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
{ {