Use a helper function to clarify gang block size

For gang blocks, `DVA_GET_ASIZE()` is the total space allocated for the
gang DVA including its children BP's.  The space allocated at each DVA's
vdev/offset is `vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE)`.

This commit makes this relationship more clear by using a helper
function, `vdev_gang_header_asize()`, for the space allocated at the
gang block's vdev/offset.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #11744

diff --git a/include/sys/spa.h b/include/sys/spa.h
index 8391be8328b6e9ff9faabd15e92de7c831315888..c960478efe50ca99d98be5b29a705ce9ab650bf2 100644 (file)
--- a/include/sys/spa.h
+++ b/include/sys/spa.h
@@ -405,6 +405,12 @@ typedef struct blkptr {
 /*
  * Macros to get and set fields in a bp or DVA.
  */
+
+/*
+ * Note, for gang blocks, DVA_GET_ASIZE() is the total space allocated for
+ * this gang DVA including its children BP's.  The space allocated at this
+ * DVA's vdev/offset is vdev_gang_header_asize(vdev).
+ */
 #define        DVA_GET_ASIZE(dva)      \
        BF64_GET_SB((dva)->dva_word[0], 0, SPA_ASIZEBITS, SPA_MINBLOCKSHIFT, 0)
 #define        DVA_SET_ASIZE(dva, x)   \

diff --git a/include/sys/vdev.h b/include/sys/vdev.h
index d1ef6b5b59b4496370afca816640d95a28ea2f95..f235bfc8cc1974c597b832c48ef01c26064bb2ba 100644 (file)
--- a/include/sys/vdev.h
+++ b/include/sys/vdev.h
@@ -133,6 +133,15 @@ extern int64_t vdev_deflated_space(vdev_t *vd, int64_t space);
 
 extern uint64_t vdev_psize_to_asize(vdev_t *vd, uint64_t psize);
 
+/*
+ * Return the amount of space allocated for a gang block header.
+ */
+static inline uint64_t
+vdev_gang_header_asize(vdev_t *vd)
+{
+       return (vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE));
+}
+
 extern int vdev_fault(spa_t *spa, uint64_t guid, vdev_aux_t aux);
 extern int vdev_degrade(spa_t *spa, uint64_t guid, vdev_aux_t aux);
 extern int vdev_online(spa_t *spa, uint64_t guid, uint64_t flags,

diff --git a/module/zfs/metaslab.c b/module/zfs/metaslab.c
index 463806c6078a0a1fa10ad373883181e430ffbac3..3b2b79b2f42f60f420ed9c95353308c4c848f731 100644 (file)
--- a/module/zfs/metaslab.c
+++ b/module/zfs/metaslab.c
@@ -5544,7 +5544,7 @@ metaslab_unalloc_dva(spa_t *spa, const dva_t *dva, uint64_t txg)
        ASSERT3P(vd->vdev_indirect_mapping, ==, NULL);
 
        if (DVA_GET_GANG(dva))
-               size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
+               size = vdev_gang_header_asize(vd);
 
        msp = vd->vdev_ms[offset >> vd->vdev_ms_shift];
 
@@ -5579,7 +5579,7 @@ metaslab_free_dva(spa_t *spa, const dva_t *dva, boolean_t checkpoint)
        ASSERT3U(spa_config_held(spa, SCL_ALL, RW_READER), !=, 0);
 
        if (DVA_GET_GANG(dva)) {
-               size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
+               size = vdev_gang_header_asize(vd);
        }
 
        metaslab_free_impl(vd, offset, size, checkpoint);
@@ -5768,7 +5768,7 @@ metaslab_claim_dva(spa_t *spa, const dva_t *dva, uint64_t txg)
        ASSERT(DVA_IS_VALID(dva));
 
        if (DVA_GET_GANG(dva))
-               size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
+               size = vdev_gang_header_asize(vd);
 
        return (metaslab_claim_impl(vd, offset, size, txg));
 }
@@ -6034,7 +6034,7 @@ metaslab_check_free(spa_t *spa, const blkptr_t *bp)
                uint64_t size = DVA_GET_ASIZE(&bp->blk_dva[i]);
 
                if (DVA_GET_GANG(&bp->blk_dva[i]))
-                       size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
+                       size = vdev_gang_header_asize(vd);
 
                ASSERT3P(vd, !=, NULL);
 

diff --git a/module/zfs/zio.c b/module/zfs/zio.c
index 23d45ded6270b67430d91d008c8fba0fdc098a58..d97c8ddc95cfe9ea82927d3649f98fb290716dbc 100644 (file)
--- a/module/zfs/zio.c
+++ b/module/zfs/zio.c
@@ -995,7 +995,8 @@ zfs_blkptr_verify(spa_t *spa, const blkptr_t *bp, boolean_t config_held,
         * that are in the log) to be arbitrarily large.
         */
        for (int i = 0; i < BP_GET_NDVAS(bp); i++) {
-               uint64_t vdevid = DVA_GET_VDEV(&bp->blk_dva[i]);
+               const dva_t *dva = &bp->blk_dva[i];
+               uint64_t vdevid = DVA_GET_VDEV(dva);
 
                if (vdevid >= spa->spa_root_vdev->vdev_children) {
                        errors += zfs_blkptr_verify_log(spa, bp, blk_verify,
@@ -1024,10 +1025,10 @@ zfs_blkptr_verify(spa_t *spa, const blkptr_t *bp, boolean_t config_held,
                         */
                        continue;
                }
-               uint64_t offset = DVA_GET_OFFSET(&bp->blk_dva[i]);
-               uint64_t asize = DVA_GET_ASIZE(&bp->blk_dva[i]);
-               if (BP_IS_GANG(bp))
-                       asize = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
+               uint64_t offset = DVA_GET_OFFSET(dva);
+               uint64_t asize = DVA_GET_ASIZE(dva);
+               if (DVA_GET_GANG(dva))
+                       asize = vdev_gang_header_asize(vd);
                if (offset + asize > vd->vdev_asize) {
                        errors += zfs_blkptr_verify_log(spa, bp, blk_verify,
                            "blkptr at %p DVA %u has invalid OFFSET %llu",
@@ -1064,8 +1065,8 @@ zfs_dva_valid(spa_t *spa, const dva_t *dva, const blkptr_t *bp)
        uint64_t offset = DVA_GET_OFFSET(dva);
        uint64_t asize = DVA_GET_ASIZE(dva);
 
-       if (BP_IS_GANG(bp))
-               asize = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
+       if (DVA_GET_GANG(dva))
+               asize = vdev_gang_header_asize(vd);
        if (offset + asize > vd->vdev_asize)
                return (B_FALSE);
 
@@ -3984,6 +3985,9 @@ zio_vdev_io_assess(zio_t *zio)
         */
        if (zio->io_error == ENXIO && zio->io_type == ZIO_TYPE_WRITE &&
            vd != NULL && !vd->vdev_ops->vdev_op_leaf) {
+               vdev_dbgmsg(vd, "zio_vdev_io_assess(zio=%px) setting "
+                   "cant_write=TRUE due to write failure with ENXIO",
+                   zio);
                vd->vdev_cant_write = B_TRUE;
        }