| Message ID | 1490440701-12037-4-git-send-email-ashijeetacharya@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sat, 03/25 16:48, Ashijeet Acharya wrote: > Move the cluster tables loading code out of the existing > get_cluster_offset() function and implement it in separate Now it's renamed to vmdk_perform_cow() in previous patch, the commit message following it should be updated. > get_cluster_table() and vmdk_L2load() functions. This patch will help > us avoid code duplication in future patches of this series. > > Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com> > --- > block/vmdk.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 99 insertions(+) > > diff --git a/block/vmdk.c b/block/vmdk.c > index f5fda2c..a42322e 100644 > --- a/block/vmdk.c > +++ b/block/vmdk.c > @@ -1037,6 +1037,105 @@ static void vmdk_refresh_limits(BlockDriverState *bs, Error **errp) > } > > /* > + * vmdk_L2load Personally, I think vmdk_l2load is good enough, the upper case doesn't add readability but makes it slightly harder to type. > + * > + * Loads 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] == 0xffffffff) { Please use 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 = 0xffffffff; Please use 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. > + * > + * 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) Again, a static function must be introduced with the code change where it is used, at least for once. It keeps the compiler happy (-Wunused-function) and makes reviewing easy. > +{ > + 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_perform_cow > * > * Copy backing file's cluster that covers @sector_num, otherwise write zero, > -- > 2.6.2 > > Fam
On Fri, Mar 31, 2017 at 11:33 AM, Fam Zheng <famz@redhat.com> wrote: > On Sat, 03/25 16:48, Ashijeet Acharya wrote: >> Move the cluster tables loading code out of the existing >> get_cluster_offset() function and implement it in separate > > Now it's renamed to vmdk_perform_cow() in previous patch, the commit message > following it should be updated. No, I think you confused get_cluster_offset() with get_whole_cluster() here :-) I have a separate patch 5/7 which renames get_cluster_offset(), so the commit message is fine till this stage. > >> get_cluster_table() and vmdk_L2load() functions. This patch will help >> us avoid code duplication in future patches of this series. >> >> Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com> >> --- >> block/vmdk.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 99 insertions(+) >> >> diff --git a/block/vmdk.c b/block/vmdk.c >> index f5fda2c..a42322e 100644 >> --- a/block/vmdk.c >> +++ b/block/vmdk.c >> @@ -1037,6 +1037,105 @@ static void vmdk_refresh_limits(BlockDriverState *bs, Error **errp) >> } >> >> /* >> + * vmdk_L2load > > Personally, I think vmdk_l2load is good enough, the upper case doesn't add > readability but makes it slightly harder to type. Done. > >> + * >> + * Loads 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] == 0xffffffff) { > > Please use UINT32_MAX. Done. > >> + 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; > > Please use UINT32_MAX. Done. > >> + 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. >> + * >> + * 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) > > Again, a static function must be introduced with the code change where it is > used, at least for once. It keeps the compiler happy (-Wunused-function) and > makes reviewing easy. Done. Ashijeet
diff --git a/block/vmdk.c b/block/vmdk.c index f5fda2c..a42322e 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -1037,6 +1037,105 @@ static void vmdk_refresh_limits(BlockDriverState *bs, Error **errp) } /* + * vmdk_L2load + * + * Loads 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] == 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; + } + + 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. + * + * 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_perform_cow * * Copy backing file's cluster that covers @sector_num, otherwise write zero,
Move the cluster tables loading code out of the existing get_cluster_offset() function and implement it in separate get_cluster_table() and vmdk_L2load() functions. This patch will help us avoid code duplication in future patches of this series. Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com> --- block/vmdk.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+)