From c93a168ddec422d7e3f58622c775323622343ef1 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 14 Feb 2012 11:13:32 +0100 Subject: [PATCH 07/99] bochs: use pread RH-Author: Kevin Wolf Message-id: <1329218101-24213-8-git-send-email-kwolf@redhat.com> Patchwork-id: 37201 O-Subject: [RHEL-6.3 qemu-kvm PATCH v2 07/96] bochs: use pread Bugzilla: 783950 RH-Acked-by: Paolo Bonzini RH-Acked-by: Marcelo Tosatti RH-Acked-by: Laszlo Ersek From: Christoph Hellwig Bugzilla: 783950 Use pread instead of lseek + read in preparation of using the qemu block API. Signed-off-by: Christoph Hellwig Signed-off-by: Kevin Wolf (cherry picked from commit efbca10f10af2c0d7282e5dc49713479be98880b) --- block/bochs.c | 63 ++++++++++++++++++-------------------------------------- 1 files changed, 20 insertions(+), 43 deletions(-) Signed-off-by: Michal Novotny --- block/bochs.c | 63 ++++++++++++++++++-------------------------------------- 1 files changed, 20 insertions(+), 43 deletions(-) diff --git a/block/bochs.c b/block/bochs.c index e952670..b54f54d 100644 --- a/block/bochs.c +++ b/block/bochs.c @@ -125,7 +125,7 @@ static int bochs_open(BlockDriverState *bs, const char *filename, int flags) s->fd = fd; - if (read(fd, &bochs, sizeof(bochs)) != sizeof(bochs)) { + if (pread(fd, &bochs, sizeof(bochs), 0) != sizeof(bochs)) { goto fail; } @@ -144,14 +144,10 @@ static int bochs_open(BlockDriverState *bs, const char *filename, int flags) bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512; } - if (lseek(s->fd, le32_to_cpu(bochs.header), SEEK_SET) == (off_t)-1) { - goto fail; - } - s->catalog_size = le32_to_cpu(bochs.extra.redolog.catalog); s->catalog_bitmap = qemu_malloc(s->catalog_size * 4); - if (read(s->fd, s->catalog_bitmap, s->catalog_size * 4) != - s->catalog_size * 4) + if (pread(s->fd, s->catalog_bitmap, s->catalog_size * 4, + le32_to_cpu(bochs.header)) != s->catalog_size * 4) goto fail; for (i = 0; i < s->catalog_size; i++) le32_to_cpus(&s->catalog_bitmap[i]); @@ -169,54 +165,35 @@ static int bochs_open(BlockDriverState *bs, const char *filename, int flags) return -1; } -static inline int seek_to_sector(BlockDriverState *bs, int64_t sector_num) +static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num) { BDRVBochsState *s = bs->opaque; int64_t offset = sector_num * 512; - int64_t extent_index, extent_offset, bitmap_offset, block_offset; + int64_t extent_index, extent_offset, bitmap_offset; char bitmap_entry; // seek to sector extent_index = offset / s->extent_size; extent_offset = (offset % s->extent_size) / 512; - if (s->catalog_bitmap[extent_index] == 0xffffffff) - { -// fprintf(stderr, "page not allocated [%x - %x:%x]\n", -// sector_num, extent_index, extent_offset); - return -1; // not allocated + if (s->catalog_bitmap[extent_index] == 0xffffffff) { + return -1; /* not allocated */ } bitmap_offset = s->data_offset + (512 * s->catalog_bitmap[extent_index] * (s->extent_blocks + s->bitmap_blocks)); - block_offset = bitmap_offset + (512 * (s->bitmap_blocks + extent_offset)); - -// fprintf(stderr, "sect: %x [ext i: %x o: %x] -> %x bitmap: %x block: %x\n", -// sector_num, extent_index, extent_offset, -// le32_to_cpu(s->catalog_bitmap[extent_index]), -// bitmap_offset, block_offset); - - // read in bitmap for current extent - if (lseek(s->fd, bitmap_offset + (extent_offset / 8), SEEK_SET) == - (off_t)-1) { - return -1; - } - if (read(s->fd, &bitmap_entry, 1) != 1) + /* read in bitmap for current extent */ + if (pread(s->fd, &bitmap_entry, 1, bitmap_offset + (extent_offset / 8)) + != 1) { return -1; - - if (!((bitmap_entry >> (extent_offset % 8)) & 1)) - { -// fprintf(stderr, "sector (%x) in bitmap not allocated\n", -// sector_num); - return -1; // not allocated } - if (lseek(s->fd, block_offset, SEEK_SET) == (off_t)-1) { - return -1; + if (!((bitmap_entry >> (extent_offset % 8)) & 1)) { + return -1; /* not allocated */ } - return 0; + return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset)); } static int bochs_read(BlockDriverState *bs, int64_t sector_num, @@ -226,13 +203,13 @@ static int bochs_read(BlockDriverState *bs, int64_t sector_num, int ret; while (nb_sectors > 0) { - if (!seek_to_sector(bs, sector_num)) - { - ret = read(s->fd, buf, 512); - if (ret != 512) - return -1; - } - else + int64_t block_offset = seek_to_sector(bs, sector_num); + if (block_offset >= 0) { + ret = pread(s->fd, buf, 512, block_offset); + if (ret != 512) { + return -1; + } + } else memset(buf, 0, 512); nb_sectors--; sector_num++; -- 1.7.7.5