storage: correct terminology in log line for disk stalls

[itsbilal]

Previously, we'd use the term "file write stall" in the log line for a disk stall, and not use the term "disk stall" which is what metrics and documentation refers to this event as. Furthermore, "write stalls" are a different, unrelated kind of stall in Pebble.

This change addresses this by changing the wording to refer to this event as a "disk stall" in the log.

Epic: none

Release note (ops change): Updates the error message in case of stalled disks to use the appropriate term for that event ("disk stall"), which is also what metrics/dashboards refer to that event as.

[blathers-crl]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}

[cockroach-teamcity]

This change is 

[nicktrav]

The change to use "file write stall" was done at @jbowens's request, here, last time we touched this. I don't have a strong opinion, just want to point out that this has come up before.

edit: maybe you could do disk stall: file write: ...?

[jbowens]

I think this language was deliberately changed to "file write stall" after we once saw a single large (megabytes) write take long enough to trigger the disk stall detector. I do think that that change confused more than it clarified, so this

With hindsight, I wish we named "write stalls" as "engine stalls," and "disk stalls" as "IO stalls."

Reviewable status: complete! 1 of 0 LGTMs obtained

[itsbilal]

@jbowens ah okay, that's good to know. I didn't realize we've litigated this already, I just guessed it was a mistake from the last time we touched this code. The other option is "file write disk stall". I just want a more direct connection between this event and the term "disk stall" but it's not the most pressing thing either. I don't mind closing this PR

[jbowens]

@itsbilal Idk, I say merge it. It's probably most important that the end user understand which of the two concepts they're observing: a disk stall or a write stall.

[itsbilal]

Sounds good. Thanks!

bors r=jbowens

[craig]

Build succeeded:

• Bazel Essential CI (Cockroach)