Clarify zinject(8) explanation of -e

Error injection of EIO or ENXIO simply sets the zio's io_error value, rather than preventing the read or write from occurring. This is important information as it affects how the probes must be used. Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: George Melikov <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes openzfs#7172
tonyhutter · Mar 6, 2018 · a655dc1 · a655dc1
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commit a655dc1
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diff --git a/man/man8/zinject.8 b/man/man8/zinject.8
@@ -111,6 +111,9 @@ Specify
 .BR "dtl" " for an ECHILD error,"
 .BR "io" " for an EIO error where reopening the device will succeed, or"
 .BR "nxio" " for an ENXIO error where reopening the device will fail."
+For EIO and ENXIO, the "failed" reads or writes still occur.  The probe simply
+sets the error value reported by the I/O pipeline so it appears the read or
+write failed.
 .TP
 .BI "\-f" " frequency"
 Only inject errors a fraction of the time. Expressed as a real number