Fix reporting of CKSUM errors in indirect vdevs

When removing and subsequently reattaching a vdev, CKSUM errors may
occur as vdev_indirect_read_all() reads from all children of a mirror
in case of a resilver.

Fix this by checking whether a child is missing the data and setting a
flag (ic_error) which is then checked in vdev_indirect_repair() and
suppresses incrementing the checksum counter.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes #11277
This commit is contained in:
George Amanakis
2020-12-11 21:15:37 +01:00
committed by GitHub
parent 1ad07b01bc
commit c76a40bfda
4 changed files with 97 additions and 11 deletions
+21 -9
View File
@@ -239,6 +239,7 @@ typedef struct indirect_child {
*/
struct indirect_child *ic_duplicate;
list_node_t ic_node; /* node on is_unique_child */
int ic_error; /* set when a child does not contain the data */
} indirect_child_t;
/*
@@ -1272,15 +1273,14 @@ vdev_indirect_read_all(zio_t *zio)
continue;
/*
* Note, we may read from a child whose DTL
* indicates that the data may not be present here.
* While this might result in a few i/os that will
* likely return incorrect data, it simplifies the
* code since we can treat scrub and resilver
* identically. (The incorrect data will be
* detected and ignored when we verify the
* checksum.)
* If a child is missing the data, set ic_error. Used
* in vdev_indirect_repair(). We perform the read
* nevertheless which provides the opportunity to
* reconstruct the split block if at all possible.
*/
if (vdev_dtl_contains(ic->ic_vdev, DTL_MISSING,
zio->io_txg, 1))
ic->ic_error = SET_ERROR(ESTALE);
ic->ic_data = abd_alloc_sametype(zio->io_abd,
is->is_size);
@@ -1410,7 +1410,11 @@ vdev_indirect_checksum_error(zio_t *zio,
* Issue repair i/os for any incorrect copies. We do this by comparing
* each split segment's correct data (is_good_child's ic_data) with each
* other copy of the data. If they differ, then we overwrite the bad data
* with the good copy. Note that we do this without regard for the DTL's,
* with the good copy. The DTL is checked in vdev_indirect_read_all() and
* if a vdev is missing a copy of the data we set ic_error and the read is
* performed. This provides the opportunity to reconstruct the split block
* if at all possible. ic_error is checked here and if set it suppresses
* incrementing the checksum counter. Aside from this DTLs are not checked,
* which simplifies this code and also issues the optimal number of writes
* (based on which copies actually read bad data, as opposed to which we
* think might be wrong). For the same reason, we always use
@@ -1447,6 +1451,14 @@ vdev_indirect_repair(zio_t *zio)
ZIO_FLAG_IO_REPAIR | ZIO_FLAG_SELF_HEAL,
NULL, NULL));
/*
* If ic_error is set the current child does not have
* a copy of the data, so suppress incrementing the
* checksum counter.
*/
if (ic->ic_error == ESTALE)
continue;
vdev_indirect_checksum_error(zio, is, ic);
}
}