Add ddt_object_count() error handling

The interface for the ddt_zap_count() function assumes it can
never fail.  However, internally ddt_zap_count() is implemented
with zap_count() which can potentially fail.  Now because there
was no way to return the error to the caller a VERIFY was used
to ensure this case never happens.

Unfortunately, it has been observed that pools can be damaged in
such a way that zap_count() fails.  The result is that the pool can
not be imported without hitting the VERIFY and crashing the system.

This patch reworks ddt_object_count() so the error can be safely
caught and returned to the caller.  This allows a pool which has
be damaged in this way to be safely rewound for import.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #910
This commit is contained in:
Brian Behlendorf
2012-10-26 10:01:49 -07:00
parent 178e73b376
commit e8fd45a0f9
4 changed files with 28 additions and 19 deletions
+3 -3
View File
@@ -163,7 +163,7 @@ typedef struct ddt_ops {
dmu_tx_t *tx);
int (*ddt_op_walk)(objset_t *os, uint64_t object, ddt_entry_t *dde,
uint64_t *walk);
uint64_t (*ddt_op_count)(objset_t *os, uint64_t object);
int (*ddt_op_count)(objset_t *os, uint64_t object, uint64_t *count);
} ddt_ops_t;
#define DDT_NAMELEN 80
@@ -172,8 +172,8 @@ extern void ddt_object_name(ddt_t *ddt, enum ddt_type type,
enum ddt_class class, char *name);
extern int ddt_object_walk(ddt_t *ddt, enum ddt_type type,
enum ddt_class class, uint64_t *walk, ddt_entry_t *dde);
extern uint64_t ddt_object_count(ddt_t *ddt, enum ddt_type type,
enum ddt_class class);
extern int ddt_object_count(ddt_t *ddt, enum ddt_type type,
enum ddt_class class, uint64_t *count);
extern int ddt_object_info(ddt_t *ddt, enum ddt_type type,
enum ddt_class class, dmu_object_info_t *);
extern boolean_t ddt_object_exists(ddt_t *ddt, enum ddt_type type,