From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38395) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dGPlR-00060t-Hj for qemu-devel@nongnu.org; Thu, 01 Jun 2017 09:03:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dGPlL-0004Dg-9y for qemu-devel@nongnu.org; Thu, 01 Jun 2017 09:03:45 -0400 Date: Thu, 1 Jun 2017 21:03:30 +0800 From: Fam Zheng Message-ID: <20170601130330.GE13127@lemon.lan> References: <1492838021-10538-1-git-send-email-ashijeetacharya@gmail.com> <1492838021-10538-5-git-send-email-ashijeetacharya@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1492838021-10538-5-git-send-email-ashijeetacharya@gmail.com> Subject: Re: [Qemu-devel] [PATCH v4 4/8] vmdk: Factor out metadata loading code out of vmdk_get_cluster_offset() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Ashijeet Acharya Cc: kwolf@redhat.com, jsnow@redhat.com, mreitz@redhat.com, stefanha@gmail.com, qemu-devel@nongnu.org, qemu-block@nongnu.org On Sat, 04/22 10:43, Ashijeet Acharya wrote: > Move the cluster tables loading code out of the existing > vmdk_get_cluster_offset() function and implement it in separate > get_cluster_table() and vmdk_L2load() functions. This patch will help Now vmdk_L2load is in lower case, "vmdk_l2load". > us avoid code duplication in future patches of this series. Bikeshedding: "of this series" is meaningful now, but not quite so once this patch becomes a commit in qemu.git - the series information will be missing. > > Signed-off-by: Ashijeet Acharya > --- > block/vmdk.c | 153 ++++++++++++++++++++++++++++++++++++++++------------------- > 1 file changed, 105 insertions(+), 48 deletions(-) > > diff --git a/block/vmdk.c b/block/vmdk.c > index f403981..4cee868 100644 > --- a/block/vmdk.c > +++ b/block/vmdk.c > @@ -1143,6 +1143,105 @@ static int vmdk_L2update(VmdkExtent *extent, VmdkMetaData *m_data, > return VMDK_OK; > } > > +/* > + * vmdk_l2load > + * > + * Load a new L2 table into memory. If the table is in the cache, the cache > + * is used; otherwise the L2 table is loaded from the image file. > + * > + * Returns: > + * VMDK_OK: on success > + * VMDK_ERROR: in error cases > + */ > +static int vmdk_l2load(VmdkExtent *extent, uint64_t offset, int l2_offset, > + uint32_t **new_l2_table, int *new_l2_index) > +{ > + int min_index, i, j; > + uint32_t *l2_table; > + uint32_t min_count; > + > + for (i = 0; i < L2_CACHE_SIZE; i++) { > + if (l2_offset == extent->l2_cache_offsets[i]) { > + /* increment the hit count */ > + if (++extent->l2_cache_counts[i] == UINT32_MAX) { > + for (j = 0; j < L2_CACHE_SIZE; j++) { > + extent->l2_cache_counts[j] >>= 1; > + } > + } > + l2_table = extent->l2_cache + (i * extent->l2_size); > + goto found; > + } > + } > + /* not found: load a new entry in the least used one */ > + min_index = 0; > + min_count = UINT32_MAX; > + for (i = 0; i < L2_CACHE_SIZE; i++) { > + if (extent->l2_cache_counts[i] < min_count) { > + min_count = extent->l2_cache_counts[i]; > + min_index = i; > + } > + } > + l2_table = extent->l2_cache + (min_index * extent->l2_size); > + if (bdrv_pread(extent->file, > + (int64_t)l2_offset * 512, > + l2_table, > + extent->l2_size * sizeof(uint32_t) > + ) != extent->l2_size * sizeof(uint32_t)) { > + return VMDK_ERROR; > + } > + > + extent->l2_cache_offsets[min_index] = l2_offset; > + extent->l2_cache_counts[min_index] = 1; > +found: > + *new_l2_index = ((offset >> 9) / extent->cluster_sectors) % extent->l2_size; > + *new_l2_table = l2_table; > + > + return VMDK_OK; > +} > + > +/* > + * get_cluster_table > + * > + * for a given offset, load (and allocate if needed) the l2 table. More consistent if you capitalize the first letter "For". > + * > + * Returns: > + * VMDK_OK: on success > + * > + * VMDK_UNALLOC: if cluster is not mapped > + * > + * VMDK_ERROR: in error cases > + */ > +static int get_cluster_table(VmdkExtent *extent, uint64_t offset, > + int *new_l1_index, int *new_l2_offset, > + int *new_l2_index, uint32_t **new_l2_table) > +{ > + int l1_index, l2_offset, l2_index; > + uint32_t *l2_table; > + int ret; > + > + offset -= (extent->end_sector - extent->sectors) * SECTOR_SIZE; > + l1_index = (offset >> 9) / extent->l1_entry_sectors; > + if (l1_index >= extent->l1_size) { > + return VMDK_ERROR; > + } > + l2_offset = extent->l1_table[l1_index]; > + if (!l2_offset) { > + return VMDK_UNALLOC; > + } > + > + ret = vmdk_l2load(extent, offset, l2_offset, &l2_table, &l2_index); > + if (ret < 0) { > + return ret; > + } > + > + *new_l1_index = l1_index; > + *new_l2_offset = l2_offset; > + *new_l2_index = l2_index; > + *new_l2_table = l2_table; > + > + return VMDK_OK; > +} > + > /** > * vmdk_get_cluster_offset > * > @@ -1172,66 +1271,24 @@ static int vmdk_get_cluster_offset(BlockDriverState *bs, > uint64_t skip_start_bytes, > uint64_t skip_end_bytes) > { > - unsigned int l1_index, l2_offset, l2_index; > - int min_index, i, j; > - uint32_t min_count, *l2_table; > + int l1_index, l2_offset, l2_index; > + uint32_t *l2_table; > bool zeroed = false; > int64_t ret; > int64_t cluster_sector; > > - if (m_data) { > - m_data->valid = 0; > - } > if (extent->flat) { > *cluster_offset = extent->flat_start_offset; > return VMDK_OK; > } > > - offset -= (extent->end_sector - extent->sectors) * SECTOR_SIZE; > - l1_index = (offset >> 9) / extent->l1_entry_sectors; > - if (l1_index >= extent->l1_size) { > - return VMDK_ERROR; > - } > - l2_offset = extent->l1_table[l1_index]; > - if (!l2_offset) { > - return VMDK_UNALLOC; > - } > - for (i = 0; i < L2_CACHE_SIZE; i++) { > - if (l2_offset == extent->l2_cache_offsets[i]) { > - /* increment the hit count */ > - if (++extent->l2_cache_counts[i] == 0xffffffff) { > - for (j = 0; j < L2_CACHE_SIZE; j++) { > - extent->l2_cache_counts[j] >>= 1; > - } > - } > - l2_table = extent->l2_cache + (i * extent->l2_size); > - goto found; > - } > - } > - /* not found: load a new entry in the least used one */ > - min_index = 0; > - min_count = 0xffffffff; > - for (i = 0; i < L2_CACHE_SIZE; i++) { > - if (extent->l2_cache_counts[i] < min_count) { > - min_count = extent->l2_cache_counts[i]; > - min_index = i; > - } > - } > - l2_table = extent->l2_cache + (min_index * extent->l2_size); > - if (bdrv_pread(extent->file, > - (int64_t)l2_offset * 512, > - l2_table, > - extent->l2_size * sizeof(uint32_t) > - ) != extent->l2_size * sizeof(uint32_t)) { > - return VMDK_ERROR; > + ret = get_cluster_table(extent, offset, &l1_index, &l2_offset, > + &l2_index, &l2_table); > + if (ret < 0) { > + return ret; > } > > - extent->l2_cache_offsets[min_index] = l2_offset; > - extent->l2_cache_counts[min_index] = 1; > - found: > - l2_index = ((offset >> 9) / extent->cluster_sectors) % extent->l2_size; > cluster_sector = le32_to_cpu(l2_table[l2_index]); > - > if (extent->has_zero_grain && cluster_sector == VMDK_GTE_ZEROED) { > zeroed = true; > } > -- > 2.6.2 > Apart from the cosmetic nits: Reviewed-by: Fam Zheng