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| author |   Conrad Meyer <cse.cem@gmail.com> | 2014-06-06 14:36:37 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2014-06-06 16:08:10 -0700 |
| commit | 190a8843ded231638d0e7ae7d8ca6a712472d114 (patch) | |
| tree | 30e99192bc39f30584197eab47b119478d8dfe37 /fs/fat/fat.h | |
| parent | fs/hpfs: increase pr_warn level (diff) | |
| download | linux-dev-190a8843ded231638d0e7ae7d8ca6a712472d114.tar.xz linux-dev-190a8843ded231638d0e7ae7d8ca6a712472d114.zip | |
fs/fat/: add support for DOS 1.x formatted volumes
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
[hirofumi@mail.parknet.co.jp: fix missed error code]
Signed-off-by: Conrad Meyer <cse.cem@gmail.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Tested-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/fat/fat.h')
| -rw-r--r-- | fs/fat/fat.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/fat/fat.h b/fs/fat/fat.h index 7c31f4bc74a9..e0c4ba39a377 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 */ }; #define FAT_HASH_BITS 8 |