RFC [buildbot] Illumos-5701 zpool list reports incorrect "alloc" value for cache devices

[kernelOfTruth]

Reviewed by: Matthew Ahrens [email protected]
Reviewed by: George Wilson [email protected]
Reviewed by: Alek Pinchuk [email protected]
Approved by: Dan McDonald [email protected]

RFC:

was
arc_space_return(HDR_L2ONLY_SIZE, ARC_SPACE_L2HDRS);

correctly placed at

@arc_hdr_l2hdr_destroy(arc_buf_hdr_t *hdr)

?

Block:

+   /*
+    * If the l2hdr's b_daddr is equal to L2ARC_ADDR_UNSET, then
+    * this header is being processed by l2arc_write_buffers() (i.e.
+    * it's in the first stage of l2arc_write_buffers()).
+    * Re-affirming that truth here, just to serve as a reminder. If
+    * b_daddr does not equal L2ARC_ADDR_UNSET, then the header may or
+    * may not have its HDR_L2_WRITING flag set. (the write may have
+    * completed, in which case HDR_L2_WRITING will be false and the
+    * b_daddr field will point to the address of the buffer on disk).
+    */
+// IMPLY(l2hdr->b_daddr == L2ARC_ADDR_UNSET, HDR_L2_WRITING(hdr));

1883 to 1893 applicable to ZFSOnLinux ?

[kernelOfTruth]

@behlendorf is the block with

IMPLY(l2hdr->b_daddr == L2ARC_ADDR_UNSET, HDR_L2_WRITING(hdr));

needed on ZFSOnLinux - it seems to be specific to Illumos derivatives and a previous "incarnation" of this patch has been tested positively with that part commented out

also I'm not sure if

arc_space_return(HDR_L2ONLY_SIZE, ARC_SPACE_L2HDRS);

was correctly placed at

@arc_hdr_l2hdr_destroy(arc_buf_hdr_t *hdr)

in that port

[behlendorf]

Merged to master as:

d962d5d Illumos 5701 - zpool list reports incorrect "alloc" value for cache devi

Expect a follow up patch stack fairly soon to resolve as many of the outstanding ARC discrepancies between upstream and ZoL.