Persist newly allocated extent mapping - #98
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simplefs_file_get_block() fills in a new extent but leaves the ei_block buffer clean, so the mapping reaches disk only if some later operation happens to dirty the same buffer. If the buffer is reclaimed first, the extent is lost and its data blocks leak.
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When
simplefs_file_get_block()allocates a new extent it writesee_start,ee_lenandee_blockinto theei_blockbuffer, then falls through tobrelse()without ever marking that buffer dirty.A clean buffer can be reclaimed at any point. If that happens before some later operation dirties the same
ei_block, the extent record never reaches disk.Summary by cubic
Mark the extent index buffer dirty when allocating a new extent so the mapping is written to disk. This prevents losing the extent record if a clean buffer is reclaimed and avoids leaking data blocks.
Written for commit cc82756. Summary will update on new commits.