| Message ID | 20170522211205.14265-6-hpoussin@reactos.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Hervé, On 05/22/2017 06:11 PM, Hervé Poussineau wrote: > - offset_to_bootsector is the number of sectors up to FAT bootsector > - offset_to_fat is the number of sectors up to first File Allocation Table > - offset_to_root_dir is the number of sectors up to root directory sector Eventually your commit description can end here, adding the 3 following lines below the "---" separator. > Replace first_sectors_number - 1 by offset_to_bootsector. > Replace first_sectors_number by offset_to_fat. > Replace faked_sectors by offset_to_rootdir. This is "offset_to_root_dir" > > Signed-off-by: Hervé Poussineau <hpoussin@reactos.org> > --- ^-- separator > block/vvfat.c | 70 ++++++++++++++++++++++++++++++++++++----------------------- > 1 file changed, 43 insertions(+), 27 deletions(-) > > diff --git a/block/vvfat.c b/block/vvfat.c > index 6a36d4f7fa..e694d82df4 100644 > --- a/block/vvfat.c > +++ b/block/vvfat.c > @@ -320,22 +320,24 @@ static void print_mapping(const struct mapping_t* mapping); > typedef struct BDRVVVFATState { > CoMutex lock; > BlockDriverState* bs; /* pointer to parent */ > - unsigned int first_sectors_number; /* 1 for a single partition, 0x40 for a disk with partition table */ > unsigned char first_sectors[0x40*0x200]; > > int fat_type; /* 16 or 32 */ > array_t fat,directory,mapping; > char volume_label[11]; > > + uint32_t offset_to_bootsector; /* 0 for floppy, 0x3f for disk */ > + > unsigned int cluster_size; > unsigned int sectors_per_cluster; > unsigned int sectors_per_fat; > unsigned int sectors_of_root_directory; > uint32_t last_cluster_of_root_directory; > - unsigned int faked_sectors; /* how many sectors are faked before file data */ > uint32_t sector_count; /* total number of sectors of the partition */ > uint32_t cluster_count; /* total number of clusters of this partition */ > uint32_t max_fat_value; > + uint32_t offset_to_fat; > + uint32_t offset_to_root_dir; > > int current_fd; > mapping_t* current_mapping; > @@ -394,15 +396,15 @@ static void init_mbr(BDRVVVFATState *s, int cyls, int heads, int secs) > partition->attributes=0x80; /* bootable */ > > /* LBA is used when partition is outside the CHS geometry */ > - lba = sector2CHS(&partition->start_CHS, s->first_sectors_number - 1, > + lba = sector2CHS(&partition->start_CHS, s->offset_to_bootsector, > cyls, heads, secs); > lba |= sector2CHS(&partition->end_CHS, s->bs->total_sectors - 1, > cyls, heads, secs); > > /*LBA partitions are identified only by start/length_sector_long not by CHS*/ > - partition->start_sector_long = cpu_to_le32(s->first_sectors_number - 1); > + partition->start_sector_long = cpu_to_le32(s->offset_to_bootsector); > partition->length_sector_long = cpu_to_le32(s->bs->total_sectors > - - s->first_sectors_number + 1); > + - s->offset_to_bootsector); > > /* FAT12/FAT16/FAT32 */ > /* DOS uses different types when partition is LBA, > @@ -823,12 +825,12 @@ static int read_directory(BDRVVVFATState* s, int mapping_index) > > static inline uint32_t sector2cluster(BDRVVVFATState* s,off_t sector_num) > { > - return (sector_num-s->faked_sectors)/s->sectors_per_cluster; > + return (sector_num - s->offset_to_root_dir) / s->sectors_per_cluster; > } > > static inline off_t cluster2sector(BDRVVVFATState* s, uint32_t cluster_num) > { > - return s->faked_sectors + s->sectors_per_cluster * cluster_num; > + return s->offset_to_root_dir + s->sectors_per_cluster * cluster_num; > } > > static int init_directories(BDRVVVFATState* s, > @@ -855,6 +857,9 @@ static int init_directories(BDRVVVFATState* s, > i = 1+s->sectors_per_cluster*0x200*8/s->fat_type; > s->sectors_per_fat=(s->sector_count+i)/i; /* round up */ > > + s->offset_to_fat = s->offset_to_bootsector + 1; > + s->offset_to_root_dir = s->offset_to_fat + s->sectors_per_fat * 2; > + > array_init(&(s->mapping),sizeof(mapping_t)); > array_init(&(s->directory),sizeof(direntry_t)); > > @@ -868,7 +873,6 @@ static int init_directories(BDRVVVFATState* s, > /* Now build FAT, and write back information into directory */ > init_fat(s); > > - s->faked_sectors=s->first_sectors_number+s->sectors_per_fat*2; > s->cluster_count=sector2cluster(s, s->sector_count); > > mapping = array_get_next(&(s->mapping)); > @@ -946,7 +950,8 @@ static int init_directories(BDRVVVFATState* s, > > s->current_mapping = NULL; > > - bootsector=(bootsector_t*)(s->first_sectors+(s->first_sectors_number-1)*0x200); > + bootsector = (bootsector_t *)(s->first_sectors > + + s->offset_to_bootsector * 0x200); > bootsector->jump[0]=0xeb; > bootsector->jump[1]=0x3e; > bootsector->jump[2]=0x90; > @@ -957,16 +962,18 @@ static int init_directories(BDRVVVFATState* s, > bootsector->number_of_fats=0x2; /* number of FATs */ > bootsector->root_entries=cpu_to_le16(s->sectors_of_root_directory*0x10); > bootsector->total_sectors16=s->sector_count>0xffff?0:cpu_to_le16(s->sector_count); > - bootsector->media_type=(s->first_sectors_number>1?0xf8:0xf0); /* media descriptor (f8=hd, f0=3.5 fd)*/ > + /* media descriptor: hard disk=0xf8, floppy=0xf0 */ Can you move this comment in the struct BDRVVVFATState definition, and add defines/enum for the values? Maybe use an inline function like "media_type(BDRVVVFATState *)". > + bootsector->media_type = (s->offset_to_bootsector > 0 ? 0xf8 : 0xf0); > s->fat.pointer[0] = bootsector->media_type; > bootsector->sectors_per_fat=cpu_to_le16(s->sectors_per_fat); > bootsector->sectors_per_track = cpu_to_le16(secs); > bootsector->number_of_heads = cpu_to_le16(heads); > - bootsector->hidden_sectors=cpu_to_le32(s->first_sectors_number==1?0:0x3f); > + bootsector->hidden_sectors = cpu_to_le32(s->offset_to_bootsector); I understood this change after reading backward: "uint32_t offset_to_bootsector; /* 0 for floppy, 0x3f for disk */" > bootsector->total_sectors=cpu_to_le32(s->sector_count>0xffff?s->sector_count:0); > > /* LATER TODO: if FAT32, this is wrong */ > - bootsector->u.fat16.drive_number=s->first_sectors_number==1?0:0x80; /* fda=0, hda=0x80 */ > + /* drive_number: fda=0, hda=0x80 */ > + bootsector->u.fat16.drive_number = s->offset_to_bootsector == 0 ? 0 : 0x80; > bootsector->u.fat16.current_head=0; > bootsector->u.fat16.signature=0x29; > bootsector->u.fat16.id=cpu_to_le32(0xfabe1afd); > @@ -1123,7 +1130,6 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags, > secs = s->fat_type == 12 ? 18 : 36; > s->sectors_per_cluster = 1; > } > - s->first_sectors_number = 1; > cyls = 80; > heads = 2; > } else { > @@ -1131,7 +1137,7 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags, > if (!s->fat_type) { > s->fat_type = 16; > } > - s->first_sectors_number = 0x40; > + s->offset_to_bootsector = 0x3f; > cyls = s->fat_type == 12 ? 64 : 1024; > heads = 16; > secs = 63; > @@ -1167,7 +1173,7 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags, > fprintf(stderr, "vvfat %s chs %d,%d,%d\n", > dirname, cyls, heads, secs); > > - s->sector_count = cyls * heads * secs - (s->first_sectors_number - 1); > + s->sector_count = cyls * heads * secs - s->offset_to_bootsector; > > if (qemu_opt_get_bool(opts, "rw", false)) { > if (!bdrv_is_read_only(bs)) { > @@ -1197,7 +1203,8 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags, > goto fail; > } > > - s->sector_count = s->faked_sectors + s->sectors_per_cluster*s->cluster_count; > + s->sector_count = s->offset_to_root_dir > + + s->sectors_per_cluster * s->cluster_count; > > /* Disable migration when vvfat is used rw */ > if (s->qcow) { > @@ -1213,7 +1220,7 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags, > } > } > > - if (s->first_sectors_number == 0x40) { > + if (s->offset_to_bootsector > 0) { > init_mbr(s, cyls, heads, secs); > } > > @@ -1426,15 +1433,24 @@ static int vvfat_read(BlockDriverState *bs, int64_t sector_num, > } > DLOG(fprintf(stderr, "sector %d not allocated\n", (int)sector_num)); > } > - if(sector_num<s->faked_sectors) { > - if(sector_num<s->first_sectors_number) > - memcpy(buf+i*0x200,&(s->first_sectors[sector_num*0x200]),0x200); > - else if(sector_num-s->first_sectors_number<s->sectors_per_fat) > - memcpy(buf+i*0x200,&(s->fat.pointer[(sector_num-s->first_sectors_number)*0x200]),0x200); > - else if(sector_num-s->first_sectors_number-s->sectors_per_fat<s->sectors_per_fat) > - memcpy(buf+i*0x200,&(s->fat.pointer[(sector_num-s->first_sectors_number-s->sectors_per_fat)*0x200]),0x200); > + if (sector_num < s->offset_to_root_dir) { > + if (sector_num < s->offset_to_fat) { > + memcpy(buf + i * 0x200, > + &(s->first_sectors[sector_num * 0x200]), > + 0x200); > + } else if (sector_num < s->offset_to_fat + s->sectors_per_fat) { > + memcpy(buf + i * 0x200, > + &(s->fat.pointer[(sector_num > + - s->offset_to_fat) * 0x200]), > + 0x200); > + } else if (sector_num < s->offset_to_root_dir) { > + memcpy(buf + i * 0x200, > + &(s->fat.pointer[(sector_num - s->offset_to_fat > + - s->sectors_per_fat) * 0x200]), > + 0x200); > + } > } else { > - uint32_t sector=sector_num-s->faked_sectors, > + uint32_t sector = sector_num - s->offset_to_root_dir, > sector_offset_in_cluster=(sector%s->sectors_per_cluster), > cluster_num=sector/s->sectors_per_cluster; > if(cluster_num > s->cluster_count || read_cluster(s, cluster_num) != 0) { > @@ -2046,7 +2062,7 @@ DLOG(checkpoint()); > memcpy(s->fat2, s->fat.pointer, size); > } > check = vvfat_read(s->bs, > - s->first_sectors_number, s->fat2, s->sectors_per_fat); > + s->offset_to_fat, s->fat2, s->sectors_per_fat); > if (check) { > fprintf(stderr, "Could not copy fat\n"); > return 0; > @@ -2865,7 +2881,7 @@ DLOG(checkpoint()); > * - do not allow to write non-ASCII filenames > */ > > - if (sector_num < s->first_sectors_number) > + if (sector_num < s->offset_to_fat) > return -1; > > for (i = sector2cluster(s, sector_num); > Except those style comment, this patch is Ok to me. Regards, Phil.
On 05/23/2017 11:10 PM, Philippe Mathieu-Daudé wrote: > Hi Hervé, > > On 05/22/2017 06:11 PM, Hervé Poussineau wrote: >> - offset_to_bootsector is the number of sectors up to FAT bootsector >> - offset_to_fat is the number of sectors up to first File Allocation >> Table >> - offset_to_root_dir is the number of sectors up to root directory sector > > Eventually your commit description can end here, adding the 3 following > lines below the "---" separator. No. Stuff after the --- is intended for things that are useful to reviewers, but not helpful in the long run. But in this case: > >> Replace first_sectors_number - 1 by offset_to_bootsector. Knowing the conversion that was made DOES make it easier to read this patch, even in the long run. So this information belongs before the ---.
diff --git a/block/vvfat.c b/block/vvfat.c index 6a36d4f7fa..e694d82df4 100644 --- a/block/vvfat.c +++ b/block/vvfat.c @@ -320,22 +320,24 @@ static void print_mapping(const struct mapping_t* mapping); typedef struct BDRVVVFATState { CoMutex lock; BlockDriverState* bs; /* pointer to parent */ - unsigned int first_sectors_number; /* 1 for a single partition, 0x40 for a disk with partition table */ unsigned char first_sectors[0x40*0x200]; int fat_type; /* 16 or 32 */ array_t fat,directory,mapping; char volume_label[11]; + uint32_t offset_to_bootsector; /* 0 for floppy, 0x3f for disk */ + unsigned int cluster_size; unsigned int sectors_per_cluster; unsigned int sectors_per_fat; unsigned int sectors_of_root_directory; uint32_t last_cluster_of_root_directory; - unsigned int faked_sectors; /* how many sectors are faked before file data */ uint32_t sector_count; /* total number of sectors of the partition */ uint32_t cluster_count; /* total number of clusters of this partition */ uint32_t max_fat_value; + uint32_t offset_to_fat; + uint32_t offset_to_root_dir; int current_fd; mapping_t* current_mapping; @@ -394,15 +396,15 @@ static void init_mbr(BDRVVVFATState *s, int cyls, int heads, int secs) partition->attributes=0x80; /* bootable */ /* LBA is used when partition is outside the CHS geometry */ - lba = sector2CHS(&partition->start_CHS, s->first_sectors_number - 1, + lba = sector2CHS(&partition->start_CHS, s->offset_to_bootsector, cyls, heads, secs); lba |= sector2CHS(&partition->end_CHS, s->bs->total_sectors - 1, cyls, heads, secs); /*LBA partitions are identified only by start/length_sector_long not by CHS*/ - partition->start_sector_long = cpu_to_le32(s->first_sectors_number - 1); + partition->start_sector_long = cpu_to_le32(s->offset_to_bootsector); partition->length_sector_long = cpu_to_le32(s->bs->total_sectors - - s->first_sectors_number + 1); + - s->offset_to_bootsector); /* FAT12/FAT16/FAT32 */ /* DOS uses different types when partition is LBA, @@ -823,12 +825,12 @@ static int read_directory(BDRVVVFATState* s, int mapping_index) static inline uint32_t sector2cluster(BDRVVVFATState* s,off_t sector_num) { - return (sector_num-s->faked_sectors)/s->sectors_per_cluster; + return (sector_num - s->offset_to_root_dir) / s->sectors_per_cluster; } static inline off_t cluster2sector(BDRVVVFATState* s, uint32_t cluster_num) { - return s->faked_sectors + s->sectors_per_cluster * cluster_num; + return s->offset_to_root_dir + s->sectors_per_cluster * cluster_num; } static int init_directories(BDRVVVFATState* s, @@ -855,6 +857,9 @@ static int init_directories(BDRVVVFATState* s, i = 1+s->sectors_per_cluster*0x200*8/s->fat_type; s->sectors_per_fat=(s->sector_count+i)/i; /* round up */ + s->offset_to_fat = s->offset_to_bootsector + 1; + s->offset_to_root_dir = s->offset_to_fat + s->sectors_per_fat * 2; + array_init(&(s->mapping),sizeof(mapping_t)); array_init(&(s->directory),sizeof(direntry_t)); @@ -868,7 +873,6 @@ static int init_directories(BDRVVVFATState* s, /* Now build FAT, and write back information into directory */ init_fat(s); - s->faked_sectors=s->first_sectors_number+s->sectors_per_fat*2; s->cluster_count=sector2cluster(s, s->sector_count); mapping = array_get_next(&(s->mapping)); @@ -946,7 +950,8 @@ static int init_directories(BDRVVVFATState* s, s->current_mapping = NULL; - bootsector=(bootsector_t*)(s->first_sectors+(s->first_sectors_number-1)*0x200); + bootsector = (bootsector_t *)(s->first_sectors + + s->offset_to_bootsector * 0x200); bootsector->jump[0]=0xeb; bootsector->jump[1]=0x3e; bootsector->jump[2]=0x90; @@ -957,16 +962,18 @@ static int init_directories(BDRVVVFATState* s, bootsector->number_of_fats=0x2; /* number of FATs */ bootsector->root_entries=cpu_to_le16(s->sectors_of_root_directory*0x10); bootsector->total_sectors16=s->sector_count>0xffff?0:cpu_to_le16(s->sector_count); - bootsector->media_type=(s->first_sectors_number>1?0xf8:0xf0); /* media descriptor (f8=hd, f0=3.5 fd)*/ + /* media descriptor: hard disk=0xf8, floppy=0xf0 */ + bootsector->media_type = (s->offset_to_bootsector > 0 ? 0xf8 : 0xf0); s->fat.pointer[0] = bootsector->media_type; bootsector->sectors_per_fat=cpu_to_le16(s->sectors_per_fat); bootsector->sectors_per_track = cpu_to_le16(secs); bootsector->number_of_heads = cpu_to_le16(heads); - bootsector->hidden_sectors=cpu_to_le32(s->first_sectors_number==1?0:0x3f); + bootsector->hidden_sectors = cpu_to_le32(s->offset_to_bootsector); bootsector->total_sectors=cpu_to_le32(s->sector_count>0xffff?s->sector_count:0); /* LATER TODO: if FAT32, this is wrong */ - bootsector->u.fat16.drive_number=s->first_sectors_number==1?0:0x80; /* fda=0, hda=0x80 */ + /* drive_number: fda=0, hda=0x80 */ + bootsector->u.fat16.drive_number = s->offset_to_bootsector == 0 ? 0 : 0x80; bootsector->u.fat16.current_head=0; bootsector->u.fat16.signature=0x29; bootsector->u.fat16.id=cpu_to_le32(0xfabe1afd); @@ -1123,7 +1130,6 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags, secs = s->fat_type == 12 ? 18 : 36; s->sectors_per_cluster = 1; } - s->first_sectors_number = 1; cyls = 80; heads = 2; } else { @@ -1131,7 +1137,7 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags, if (!s->fat_type) { s->fat_type = 16; } - s->first_sectors_number = 0x40; + s->offset_to_bootsector = 0x3f; cyls = s->fat_type == 12 ? 64 : 1024; heads = 16; secs = 63; @@ -1167,7 +1173,7 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags, fprintf(stderr, "vvfat %s chs %d,%d,%d\n", dirname, cyls, heads, secs); - s->sector_count = cyls * heads * secs - (s->first_sectors_number - 1); + s->sector_count = cyls * heads * secs - s->offset_to_bootsector; if (qemu_opt_get_bool(opts, "rw", false)) { if (!bdrv_is_read_only(bs)) { @@ -1197,7 +1203,8 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags, goto fail; } - s->sector_count = s->faked_sectors + s->sectors_per_cluster*s->cluster_count; + s->sector_count = s->offset_to_root_dir + + s->sectors_per_cluster * s->cluster_count; /* Disable migration when vvfat is used rw */ if (s->qcow) { @@ -1213,7 +1220,7 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags, } } - if (s->first_sectors_number == 0x40) { + if (s->offset_to_bootsector > 0) { init_mbr(s, cyls, heads, secs); } @@ -1426,15 +1433,24 @@ static int vvfat_read(BlockDriverState *bs, int64_t sector_num, } DLOG(fprintf(stderr, "sector %d not allocated\n", (int)sector_num)); } - if(sector_num<s->faked_sectors) { - if(sector_num<s->first_sectors_number) - memcpy(buf+i*0x200,&(s->first_sectors[sector_num*0x200]),0x200); - else if(sector_num-s->first_sectors_number<s->sectors_per_fat) - memcpy(buf+i*0x200,&(s->fat.pointer[(sector_num-s->first_sectors_number)*0x200]),0x200); - else if(sector_num-s->first_sectors_number-s->sectors_per_fat<s->sectors_per_fat) - memcpy(buf+i*0x200,&(s->fat.pointer[(sector_num-s->first_sectors_number-s->sectors_per_fat)*0x200]),0x200); + if (sector_num < s->offset_to_root_dir) { + if (sector_num < s->offset_to_fat) { + memcpy(buf + i * 0x200, + &(s->first_sectors[sector_num * 0x200]), + 0x200); + } else if (sector_num < s->offset_to_fat + s->sectors_per_fat) { + memcpy(buf + i * 0x200, + &(s->fat.pointer[(sector_num + - s->offset_to_fat) * 0x200]), + 0x200); + } else if (sector_num < s->offset_to_root_dir) { + memcpy(buf + i * 0x200, + &(s->fat.pointer[(sector_num - s->offset_to_fat + - s->sectors_per_fat) * 0x200]), + 0x200); + } } else { - uint32_t sector=sector_num-s->faked_sectors, + uint32_t sector = sector_num - s->offset_to_root_dir, sector_offset_in_cluster=(sector%s->sectors_per_cluster), cluster_num=sector/s->sectors_per_cluster; if(cluster_num > s->cluster_count || read_cluster(s, cluster_num) != 0) { @@ -2046,7 +2062,7 @@ DLOG(checkpoint()); memcpy(s->fat2, s->fat.pointer, size); } check = vvfat_read(s->bs, - s->first_sectors_number, s->fat2, s->sectors_per_fat); + s->offset_to_fat, s->fat2, s->sectors_per_fat); if (check) { fprintf(stderr, "Could not copy fat\n"); return 0; @@ -2865,7 +2881,7 @@ DLOG(checkpoint()); * - do not allow to write non-ASCII filenames */ - if (sector_num < s->first_sectors_number) + if (sector_num < s->offset_to_fat) return -1; for (i = sector2cluster(s, sector_num);
- offset_to_bootsector is the number of sectors up to FAT bootsector - offset_to_fat is the number of sectors up to first File Allocation Table - offset_to_root_dir is the number of sectors up to root directory sector Replace first_sectors_number - 1 by offset_to_bootsector. Replace first_sectors_number by offset_to_fat. Replace faked_sectors by offset_to_rootdir. Signed-off-by: Hervé Poussineau <hpoussin@reactos.org> --- block/vvfat.c | 70 ++++++++++++++++++++++++++++++++++++----------------------- 1 file changed, 43 insertions(+), 27 deletions(-)