buffer_head: fail fast on repeated reads after I/O errors#804
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blktests-ci[bot] wants to merge 1 commit intolinus-master_basefrom
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buffer_head: fail fast on repeated reads after I/O errors#804blktests-ci[bot] wants to merge 1 commit intolinus-master_basefrom
blktests-ci[bot] wants to merge 1 commit intolinus-master_basefrom
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A failed buffer_head read leaves the buffer !Uptodate. If multiple threads hit that same buffer_head, they serialize on BH_Lock and each one re-submits the same read after the previous owner drops the lock. If the device is slow to return the error, this can turn one bad block into long stalls and repeated slow I/O. Trying to remember bad LBAs in block or drivers would need a generic per-device table with lookup, eviction, and lifetime rules. For buffer_head users, keep the failure state with the cached buffer_head instead. Track non-readahead read I/O errors in buffer_head with a dedicated bit and a failure timestamp. Update this state from the bio completion path. Add an optional per-bdev retry window: within the window, non-readahead submit_bh() reads complete immediately with failure for a buffer_head that recently saw a non-readahead read error. A successful read or rewrite clears the state. The timestamp is recorded on the first error only, so repeated failures do not extend the window. Once the window expires, the next read is submitted normally and can discover that the device or media has recovered. Configure per block device via sysfs: /sys/block/<disk>/read_err_retry_sec /sys/block/<disk>/<part>/read_err_retry_sec Default is 0, preserving existing behavior. Disk and partition values are independent, and values larger than MAX_JIFFY_OFFSET / HZ are rejected to avoid jiffies overflow. Link: https://lore.kernel.org/linux-ext4/20260325093349.630193-1-diangangli@gmail.com/ Signed-off-by: Diangang Li <lidiangang@bytedance.com>
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Upstream branch: 6d35786 |
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Pull request for series with
subject: buffer_head: fail fast on repeated reads after I/O errors
version: 1
url: https://patchwork.kernel.org/project/linux-block/list/?series=1090493