[Libguestfs] [PATCH nbdkit 1/9] cache: Rename blk_writeback function.

The blk_writeback function was misnamed, since depending on the cache mode and flags it could either do a writethrough or a writeback [write to the cache only]. Since it's really the general "write a block" function, rename it simply as blk_write. Note there exists a blk_read function already. There are several related changes in this commit, but it's entirely refactoring and makes no functional difference. --- filters/cache/cache.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/filters/cache/cache.c b/filters/cache/cache.c index e9a5c38..1dc17fd 100644 --- a/filters/cache/cache.c +++ b/filters/cache/cache.c @@ -262,8 +262,7 @@ blk_writethrough (struct nbdkit_next_ops *next_ops, void *nxdata, { off_t offset = blknum * BLKSIZE; - nbdkit_debug ("cache: blk_writethrough block %" PRIu64 - " (offset %" PRIu64 ")", + nbdkit_debug ("cache: writethrough block %" PRIu64 " (offset %" PRIu64 ")", blknum, (uint64_t) offset); if (pwrite (fd, block, BLKSIZE, offset) == -1) { @@ -280,11 +279,18 @@ blk_writethrough (struct nbdkit_next_ops *next_ops, void *nxdata, return 0; } -/* Write to the cache only. */ +/* Write a whole block. + * + * If the cache is in writethrough mode, or the FUA flag is set, then + * this calls blk_writethrough above which will write both to the + * cache and through to the underlying device. + * + * Otherwise it will only write to the cache. + */ static int -blk_writeback (struct nbdkit_next_ops *next_ops, void *nxdata, - uint64_t blknum, const uint8_t *block, uint32_t flags, - int *err) +blk_write (struct nbdkit_next_ops *next_ops, void *nxdata, + uint64_t blknum, const uint8_t *block, uint32_t flags, + int *err) { off_t offset; @@ -294,8 +300,7 @@ blk_writeback (struct nbdkit_next_ops *next_ops, void *nxdata, offset = blknum * BLKSIZE; - nbdkit_debug ("cache: blk_writeback block %" PRIu64 - " (offset %" PRIu64 ")", + nbdkit_debug ("cache: writeback block %" PRIu64 " (offset %" PRIu64 ")", blknum, (uint64_t) offset); if (pwrite (fd, block, BLKSIZE, offset) == -1) { @@ -385,7 +390,7 @@ cache_pwrite (struct nbdkit_next_ops *next_ops, void *nxdata, return -1; } memcpy (&block[blkoffs], buf, n); - if (blk_writeback (next_ops, nxdata, blknum, block, flags, err) == -1) { + if (blk_write (next_ops, nxdata, blknum, block, flags, err) == -1) { free (block); return -1; } @@ -437,7 +442,7 @@ cache_zero (struct nbdkit_next_ops *next_ops, void *nxdata, return -1; } memset (&block[blkoffs], 0, n); - if (blk_writeback (next_ops, nxdata, blknum, block, flags, err) == -1) { + if (blk_write (next_ops, nxdata, blknum, block, flags, err) == -1) { free (block); return -1; } -- 2.19.2