6c8f7fc3ba
. add all sys/sys headers not already present to help compiling . take netbsd dirent.h and struct dirent; main result is introducing d_type and d_namlen that have to be set by getdents() in all FS code implementing it . d_off is gone . alignment of the struct has become 8 bytes instead of 4 . remove _MAX_BLOCK_SIZE, _MIN_BLOCK_SIZE, _STATIC_BLOCK_SIZE . libminlib: cleanup unused yet duplicate code . mfs: throw out the long-broken v1, v2 support . new test for dirent contents filled by getdents() Change-Id: I1459755c7ba5e5d1c9396d3a587ce6e63ddc283e
35 lines
1.3 KiB
C
35 lines
1.3 KiB
C
/* Buffer (block) cache. To acquire a block, a routine calls get_block(),
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* telling which block it wants. The block is then regarded as "in use"
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* and has its 'b_count' field incremented. All the blocks that are not
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* in use are chained together in an LRU list, with 'front' pointing
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* to the least recently used block, and 'rear' to the most recently used
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* block. A reverse chain, using the field b_prev is also maintained.
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* Usage for LRU is measured by the time the put_block() is done. The second
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* parameter to put_block() can violate the LRU order and put a block on the
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* front of the list, if it will probably not be needed soon. If a block
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* is modified, the modifying routine must set b_dirt to DIRTY, so the block
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* will eventually be rewritten to the disk.
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*/
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#ifndef EXT2_BUF_H
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#define EXT2_BUF_H
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#include <sys/dirent.h>
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union fsdata_u {
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char b__data[1]; /* ordinary user data */
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/* indirect block */
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block_t b__ind[1];
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/* bit map block */
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bitchunk_t b__bitmap[1];
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};
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/* A block is free if b_dev == NO_DEV. */
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/* These defs make it possible to use to bp->b_data instead of bp->b.b__data */
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#define b_data(bp) ((union fsdata_u *) bp->data)->b__data
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#define b_ind(bp) ((union fsdata_u *) bp->data)->b__ind
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#define b_bitmap(bp) ((union fsdata_u *) bp->data)->b__bitmap
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#endif /* EXT2_BUF_H */
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