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Prevent race in blkptr_verify against device removal

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When we check the vdev of the blkptr in zfs_blkptr_verify, we can run
into a race condition where that vdev is temporarily unavailable. This
happens when a device removal operation and the old vdev_t has been
removed from the array, but the new indirect vdev has not yet been
inserted.

We hold the spa_config_lock while doing our sensitive verification.
To ensure that we don't deadlock, we only grab the lock if we don't
have config_writer held. In addition, I had to const the tags of the
refcounts and the spa_config_lock arguments.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes #9112
This commit is contained in:
Paul Dagnelie
2019-08-13 20:24:43 -07:00
committed by Tony Hutter
parent 5549a537dd
commit 93fd9101c9
5 changed files with 35 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files
module/zfs/refcount.c
+10 -9
View File
@@ -121,7 +121,7 @@ zfs_refcount_count(zfs_refcount_t *rc)
}
int64_t
zfs_refcount_add_many(zfs_refcount_t *rc, uint64_t number, void *holder)
zfs_refcount_add_many(zfs_refcount_t *rc, uint64_t number, const void *holder)
{
reference_t *ref = NULL;
int64_t count;
@@ -143,13 +143,14 @@ zfs_refcount_add_many(zfs_refcount_t *rc, uint64_t number, void *holder)
}
int64_t
zfs_refcount_add(zfs_refcount_t *rc, void *holder)
zfs_refcount_add(zfs_refcount_t *rc, const void *holder)
{
return (zfs_refcount_add_many(rc, 1, holder));
}
int64_t
zfs_refcount_remove_many(zfs_refcount_t *rc, uint64_t number, void *holder)
zfs_refcount_remove_many(zfs_refcount_t *rc, uint64_t number,
const void *holder)
{
reference_t *ref;
int64_t count;
@@ -197,7 +198,7 @@ zfs_refcount_remove_many(zfs_refcount_t *rc, uint64_t number, void *holder)
}
int64_t
zfs_refcount_remove(zfs_refcount_t *rc, void *holder)
zfs_refcount_remove(zfs_refcount_t *rc, const void *holder)
{
return (zfs_refcount_remove_many(rc, 1, holder));
}
@@ -235,7 +236,7 @@ zfs_refcount_transfer(zfs_refcount_t *dst, zfs_refcount_t *src)
void
zfs_refcount_transfer_ownership_many(zfs_refcount_t *rc, uint64_t number,
void *current_holder, void *new_holder)
const void *current_holder, const void *new_holder)
{
reference_t *ref;
boolean_t found = B_FALSE;
@@ -260,8 +261,8 @@ zfs_refcount_transfer_ownership_many(zfs_refcount_t *rc, uint64_t number,
}
void
zfs_refcount_transfer_ownership(zfs_refcount_t *rc, void *current_holder,
void *new_holder)
zfs_refcount_transfer_ownership(zfs_refcount_t *rc, const void *current_holder,
const void *new_holder)
{
return (zfs_refcount_transfer_ownership_many(rc, 1, current_holder,
new_holder));
@@ -273,7 +274,7 @@ zfs_refcount_transfer_ownership(zfs_refcount_t *rc, void *current_holder,
* might be held.
*/
boolean_t
zfs_refcount_held(zfs_refcount_t *rc, void *holder)
zfs_refcount_held(zfs_refcount_t *rc, const void *holder)
{
reference_t *ref;
@@ -301,7 +302,7 @@ zfs_refcount_held(zfs_refcount_t *rc, void *holder)
* since the reference might not be held.
*/
boolean_t
zfs_refcount_not_held(zfs_refcount_t *rc, void *holder)
zfs_refcount_not_held(zfs_refcount_t *rc, const void *holder)
{
reference_t *ref;
module/zfs/spa_misc.c
+2 -2
View File
@@ -484,7 +484,7 @@ spa_config_tryenter(spa_t *spa, int locks, void *tag, krw_t rw)
}
void
spa_config_enter(spa_t *spa, int locks, void *tag, krw_t rw)
spa_config_enter(spa_t *spa, int locks, const void *tag, krw_t rw)
{
int wlocks_held = 0;
@@ -517,7 +517,7 @@ spa_config_enter(spa_t *spa, int locks, void *tag, krw_t rw)
}
void
spa_config_exit(spa_t *spa, int locks, void *tag)
spa_config_exit(spa_t *spa, int locks, const void *tag)
{
for (int i = SCL_LOCKS - 1; i >= 0; i--) {
spa_config_lock_t *scl = &spa->spa_config_lock[i];
module/zfs/zio.c
+11 -5
View File
@@ -881,8 +881,8 @@ zio_root(spa_t *spa, zio_done_func_t *done, void *private, enum zio_flag flags)
return (zio_null(NULL, spa, NULL, done, private, flags));
}
void
zfs_blkptr_verify(spa_t *spa, const blkptr_t *bp)
static void
zfs_blkptr_verify(spa_t *spa, const blkptr_t *bp, boolean_t config_held)
{
if (!DMU_OT_IS_VALID(BP_GET_TYPE(bp))) {
zfs_panic_recover("blkptr at %p has invalid TYPE %llu",
@@ -921,6 +921,10 @@ zfs_blkptr_verify(spa_t *spa, const blkptr_t *bp)
if (!spa->spa_trust_config)
return;
if (!config_held)
spa_config_enter(spa, SCL_VDEV, bp, RW_READER);
else
ASSERT(spa_config_held(spa, SCL_VDEV, RW_WRITER));
/*
* Pool-specific checks.
*
@@ -969,6 +973,8 @@ zfs_blkptr_verify(spa_t *spa, const blkptr_t *bp)
bp, i, (longlong_t)offset);
}
}
if (!config_held)
spa_config_exit(spa, SCL_VDEV, bp);
}
boolean_t
@@ -1008,7 +1014,7 @@ zio_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
{
zio_t *zio;
zfs_blkptr_verify(spa, bp);
zfs_blkptr_verify(spa, bp, flags & ZIO_FLAG_CONFIG_WRITER);
zio = zio_create(pio, spa, BP_PHYSICAL_BIRTH(bp), bp,
data, size, size, done, private,
@@ -1101,7 +1107,7 @@ void
zio_free(spa_t *spa, uint64_t txg, const blkptr_t *bp)
{
zfs_blkptr_verify(spa, bp);
zfs_blkptr_verify(spa, bp, B_FALSE);
/*
* The check for EMBEDDED is a performance optimization. We
@@ -1166,7 +1172,7 @@ zio_claim(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
{
zio_t *zio;
zfs_blkptr_verify(spa, bp);
zfs_blkptr_verify(spa, bp, flags & ZIO_FLAG_CONFIG_WRITER);
if (BP_IS_EMBEDDED(bp))
return (zio_null(pio, spa, NULL, NULL, NULL, 0));