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authorDenys Vlasenko <vda.linux@googlemail.com>2009-11-03 13:12:04 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2009-11-03 13:12:04 (GMT)
commit692bcff577fd3844e2017ffa6864d56f7a2bb5ad (patch)
tree6a76a75f3bc7f5d4db645355923412d1bec9e357
parent68c67469aabe112cc0ef90bd87700370d96a4085 (diff)
downloadbusybox-692bcff577fd3844e2017ffa6864d56f7a2bb5ad.tar.gz
busybox-692bcff577fd3844e2017ffa6864d56f7a2bb5ad.tar.bz2
mkfs_vfat: fixes for large image cases
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--util-linux/mkfs_vfat.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/util-linux/mkfs_vfat.c b/util-linux/mkfs_vfat.c
index 10de2af..de88a74 100644
--- a/util-linux/mkfs_vfat.c
+++ b/util-linux/mkfs_vfat.c
@@ -391,16 +391,22 @@ int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
while (1) {
while (1) {
int spf_adj;
- off_t tcl = (volume_size_sect - reserved_sect - NUM_FATS * sect_per_fat) / sect_per_clust;
+ uoff_t tcl = (volume_size_sect - reserved_sect - NUM_FATS * sect_per_fat) / sect_per_clust;
// tcl may be > MAX_CLUST_32 here, but it may be
// because sect_per_fat is underestimated,
// and with increased sect_per_fat it still may become
// <= MAX_CLUST_32. Therefore, we do not check
// against MAX_CLUST_32, but against a bigger const:
- if (tcl > 0x7fffffff)
+ if (tcl > 0x80ffffff)
goto next;
total_clust = tcl; // fits in uint32_t
- spf_adj = ((total_clust + 2) * 4 + bytes_per_sect - 1) / bytes_per_sect - sect_per_fat;
+ // Every cluster needs 4 bytes in FAT. +2 entries since
+ // FAT has space for non-existent clusters 0 and 1.
+ // Let's see how many sectors that needs.
+ //May overflow at "*4":
+ //spf_adj = ((total_clust+2) * 4 + bytes_per_sect-1) / bytes_per_sect - sect_per_fat;
+ //Same in the more obscure, non-overflowing form:
+ spf_adj = ((total_clust+2) + (bytes_per_sect/4)-1) / (bytes_per_sect/4) - sect_per_fat;
#if 0
bb_error_msg("sect_per_clust:%u sect_per_fat:%u total_clust:%u",
sect_per_clust, sect_per_fat, (int)tcl);