Hello,
On Wed, 02 May 2012 19:17:41 -0700 Aaron Williams Aaron.Williams@cavium.com wrote:
This patch fixes several issues where sector offsets can overflow due to being limited to 16-bits. There are many cases which can cause an overflow, including large FAT32 partitions and partitions that start at a sufficiently large offset on the storage device.
For large FAT32 partitions only changing of fatlength, rootdir_sect and data_begin is needed to avoid overflows. Changing of fat_sect shouldn't be needed.
What do you mean exactly by "partitions starting at a sufficiently large offset on the storage device"? How do you create such partition? I've tested with a 210 GB FAT32 partition as the fourth primary partition on a 2 TB disk. This partition is the last partition on the disk, so its offset is sufficiently large. For this test only fatlength, rootdir_sect and data_begin was changed to __u32 and int and I do not see issues when listing or loading the files from this partition.
Numerous issues were observed and fixed when a 64GB FAT32 filesystem was accessed due to truncation.
Signed-off-by: Aaron Williams aaron.williams@caviumnetworks.com
include/fat.h | 10 +++++----- 1 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/include/fat.h b/include/fat.h index 4c92442..7215628 100644 --- a/include/fat.h +++ b/include/fat.h @@ -178,12 +178,12 @@ typedef struct dir_slot { typedef struct { __u8 *fatbuf; /* Current FAT buffer */ int fatsize; /* Size of FAT in bits */
__u16 fatlength; /* Length of FAT in sectors */__u16 fat_sect; /* Starting sector of the FAT */__u16 rootdir_sect; /* Start sector of root directory */__u16 sect_size; /* Size of sectors in bytes */
__u32 fat_sect; /* Starting sector of the FAT */__u32 rootdir_sect; /* Start sector of root directory */__u32 fatlength; /* Length of FAT in sectors */ __u16 clust_size; /* Size of clusters in sectors */
short data_begin; /* The sector of the first cluster, can be negative */
__u16 sect_size; /* Size of sectors in bytes */int data_begin; /* The sector of the first cluster, can be negative */ int fatbufnum; /* Used by get_fatent, init to -1 */} fsdata;
The patch is probably corrupted by your mailer, it doesn't apply.
Thanks, Anatolij