Fix corruption caused by mmap flushing problems #16039
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1) Make mmap flushes synchronous. Linux may skip flushing dirty pages already in writeback unless data-integrity sync is requested. 2) Change zfs_putpage to use TXG_WAIT. Otherwise dirty pages may be skipped due to DMU pushing back on TX assign. 3) Add missing mmap flush when doing block cloning. 4) While here, pass errors from putpage to writepage/writepages. This change fixes corruption edge cases, but unfortunately adds synchronous ZIL flushes for dirty mmap pages to llseek and bclone operations. It may be possible to avoid these sync writes later but would need more tricky refactoring of the writeback code. Reviewed-by: Alexander Motin <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Robert Evans <[email protected]> Closes openzfs#15933 Closes openzfs#16019
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rrevans
approved these changes
Mar 29, 2024
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Motivation and Context
Backport #16019
Description
Important bug fix
How Has This Been Tested?
Test built
Types of changes
Checklist:
Signed-off-by.