Unknown reader errors should close reader/tailer to avoid mtail looping on broken fds. #993
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…ng on broken fds. If mtail is tailing a file under a mount, and this mount is gone, mtail reader might block on read error: bad file descriptor .... This will DoS mtail which won't respond to standard signals and significantly increase its CPU consumption. Better strategy is to simply close reader/tailer on the broken fd and let the tailer do its job. Another retryable cases like syscall.ESTALE can be added in future, but for now fail fast seems like a logical approach.
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If mtail is tailing a file under a mount, and this mount is gone, mtail reader might block on
This will DoS mtail which won't respond to standard signals and significantly increase its CPU consumption.
Better strategy is to simply close reader/tailer on the broken fd and let the tailer do its job.
Another retryable cases like syscall.ESTALE can be added in future, but for now fail fast seems like a logical approach.