Conrad Meyer <cse....@gmail.com> writes: > Add structure for parsed BPB information, struct fat_bios_param_block, > and move all of the deserialization and validation logic from > fat_fill_super() into fat_read_bpb(). > > Add a 'dos1xfloppy' mount option to infer DOS 2.x BIOS Parameter Block > defaults from block device geometry for ancient floppies and floppy > images, as a fall-back from the default BPB parsing logic. > > When fat_read_bpb() finds an invalid FAT filesystem and dos1xfloppy is > set, fall back to fat_read_static_bpb(). fat_read_static_bpb() validates > that the entire BPB is zero, and that the floppy has a DOS-style 8086 > code bootstrapping header. Then it fills in default BPB values from > media size and a table.[0] > > Media size is assumed to be static for archaic FAT volumes. See also: > [1]. > > Fixes kernel.org bug #42617. > > [0]: https://en.wikipedia.org/wiki/File_Allocation_Table#Exceptions > [1]: http://www.win.tue.nl/~aeb/linux/fs/fat/fat-1.html > > Signed-off-by: Conrad Meyer <cse....@gmail.com> > --- > Changes since v5: > * Leave the bulk of sbi-> filling logic to the aptly named fat_fill_super() > * Create separate structure for deserialized BPB values > * fat_read_bpb() deserializes BPB from raw fat_boot_sector and performs > validations > * fat_read_static_bpb() validates raw fat_boot_sector as dos1x and fills in > BPB values from table > > Thanks, > Conrad > --- > fs/fat/fat.h | 28 ++++- > fs/fat/inode.c | 316 > +++++++++++++++++++++++++++++++++++++++++++-------------- > 2 files changed, 267 insertions(+), 77 deletions(-) > > diff --git a/fs/fat/fat.h b/fs/fat/fat.h > index 7270bdb..bcb0d67 100644 > --- a/fs/fat/fat.h > +++ b/fs/fat/fat.h > @@ -52,7 +52,8 @@ struct fat_mount_options { > usefree:1, /* Use free_clusters for FAT32 */ > tz_set:1, /* Filesystem timestamps' offset set */ > rodir:1, /* allow ATTR_RO for directory */ > - discard:1; /* Issue discard requests on deletions */ > + discard:1, /* Issue discard requests on deletions */ > + dos1xfloppy:1; /* Assume default BPB for DOS 1.x floppies */ > };
OK. Looks good basically. Another one I am also forgetting. Need to update show_options() and Documents/fs/vfat.txt for new option. Thanks. -- OGAWA Hirofumi <hirof...@mail.parknet.co.jp> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
