From 11daa4a2d17850ff5ceb1c30d463d699635cfbc6 Mon Sep 17 00:00:00 2001 From: Michael Vrable Date: Thu, 10 Mar 2011 20:58:10 -0800 Subject: [PATCH] Tweaks to code that handles read-modify-write on data blocks --- bluesky/file.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/bluesky/file.c b/bluesky/file.c index f10814a..e0c6255 100644 --- a/bluesky/file.c +++ b/bluesky/file.c @@ -77,6 +77,15 @@ void bluesky_file_truncate(BlueSkyInode *inode, uint64_t size) uint64_t blocks = (size + BLUESKY_BLOCK_SIZE - 1) / BLUESKY_BLOCK_SIZE; + /* Calculate number of bytes in the last block of the file */ + int lastblock_old, lastblock_new; + lastblock_old = inode->size % BLUESKY_BLOCK_SIZE; + if (lastblock_old == 0 && inode->size > 0) + lastblock_old = BLUESKY_BLOCK_SIZE; + lastblock_new = size % BLUESKY_BLOCK_SIZE; + if (lastblock_new == 0 && size > 0) + lastblock_new = BLUESKY_BLOCK_SIZE; + if (blocks > inode->blocks->len) { /* Need to add new blocks to the end of a file. New block structures * are automatically zeroed, which initializes them to be pointers to @@ -88,10 +97,10 @@ void bluesky_file_truncate(BlueSkyInode *inode, uint64_t size) inode->blocks->len - 1); if (b->type != BLUESKY_BLOCK_ZERO - && (b->type == BLUESKY_BLOCK_REF - || b->dirty->len < BLUESKY_BLOCK_SIZE)) { + && lastblock_old < BLUESKY_BLOCK_SIZE) { bluesky_block_touch(inode, inode->blocks->len - 1, TRUE); gsize old_size = b->dirty->len; + g_warn_if_fail(lastblock_old != old_size); bluesky_string_resize(b->dirty, BLUESKY_BLOCK_SIZE); memset(&b->dirty->data[old_size], 0, BLUESKY_BLOCK_SIZE - old_size); @@ -117,7 +126,13 @@ void bluesky_file_truncate(BlueSkyInode *inode, uint64_t size) BlueSkyBlock *b = &g_array_index(inode->blocks, BlueSkyBlock, blocks - 1); - if (b->type != BLUESKY_BLOCK_ZERO) { + gboolean need_resize = TRUE; + if (b->type == BLUESKY_BLOCK_ZERO) + need_resize = FALSE; + else if (size < inode->size && lastblock_new == BLUESKY_BLOCK_SIZE) + need_resize = FALSE; + + if (need_resize) { bluesky_block_touch(inode, blocks - 1, TRUE); gsize old_size = b->dirty->len; gsize new_size = size - (blocks - 1) * BLUESKY_BLOCK_SIZE; -- 2.20.1