fixup_overlap_tail(9)

💅 fixup_overlap_tail — like, the kernel API manual, bestie

okay so real quick — this page is fixup_overlap_tail(9) from the Kernel API Manual. That's the manual name, we're not copying the header line, we're just vibing with it. Let's go ✨

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🌸 NAME 🌸

fixup_overlap_tail — adjust the key when it overlaps at the tail. That's it, that's the whole job, and it does it beautifully 🎀

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✨ SYNOPSIS ✨

int fixup_overlap_tail (struct pcache_cache_key *key , struct
       pcache_cache_key *key_tmp , struct pcache_cache_subtree_walk_ctx *ctx );

yes bestie, it returns an int, and yes, those are three pointer args. no cap. 🔥

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🦋 ARGUMENTS 🦋

• key — pointer to the new cache key that's being inserted. the fresh one. the main character 👑
• key_tmp — pointer to the existing key that overlaps. the one that's already been living in the tree 🫶
• ctx — pointer to the context for walking the cache tree. the walking-our-tree-together context, iykyk 🧚

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💖 DESCRIPTION 💖

okay so here's the tea: this function modifies the existing key (key_tmp) when there's an overlap at the tail with the new key. that's the whole move 💅

and then — and this is the important part — if the modified key becomes empty, it is deleted. like, gone. zero notes. it's giving cleanup era 🗑️✨

so to recap: overlap at the tail? key_tmp gets adjusted. adjusted itself into nothing? deleted. literally that simple, periodt 🌈

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🔥 SEE ALSO 🔥

kernel file ./drivers/md/dm-pcache/cache_key.c and honestly the whole friend group:

• cache_key_get(9)
• cache_key_destroy(9)
• cache_key_append(9)
• cache_subtree_walk(9)
• cache_subtree_search(9)
• fixup_overlap_contain(9)
• fixup_overlap_contained(9)
• fixup_overlap_head(9)
• cache_key_insert(9)
• clean_fn(9)

go read them, they're iconic, i don't make the rules 💜

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🌸 okay that's the page!! shoutout to ./drivers/md/dm-pcache for hosting this whole situation, and to October 2026 for the timestamp — mwah, love u, bye bestie 🫶💖🎀