49eb1f4806
Primary purpose of change: to support the mmap implementation, VM must know both (a) about some block metadata for FS cache blocks, i.e. inode numbers and inode offsets where applicable; and (b) know about *all* cache blocks, i.e. also of the FS primary caches and not just the blocks that spill into the secondary one. This changes the interface and VM data structures. This change is only for the interface (libminixfs) and VM data structures; the filesystem code is unmodified, so although the secondary cache will be used as normal, blocks will not be annotated with inode information until the FS is modified to provide this information. Until it is modified, mmap of files will fail gracefully on such filesystems. This is indicated to VFS/VM by returning ENOSYS for REQ_PEEK. Change-Id: I1d2df6c485e6c5e89eb28d9055076cc02629594e
22 lines
773 B
C
22 lines
773 B
C
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struct cached_page {
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/* - The (dev, dev_offset) pair are unique;
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* the (ino, ino_offset) pair is information and
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* might be missing. duplicate do not make sense
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* although it won't bother VM much.
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* - dev must always be valid, i.e. not NO_DEV
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* - ino may be unknown, i.e. VMC_NO_INODE
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*/
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dev_t dev; /* which dev is it on */
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u64_t dev_offset; /* offset within dev */
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ino_t ino; /* which ino is it about */
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u64_t ino_offset; /* offset within ino */
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struct phys_block *page; /* page ptr */
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struct cached_page *older; /* older in lru chain */
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struct cached_page *newer; /* newer in lru chain */
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struct cached_page *hash_next_dev; /* next in hash chain (bydev) */
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struct cached_page *hash_next_ino; /* next in hash chain (byino) */
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};
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