I've encountered compiling troubles in compiling 2.1.47 vfat support.
make[3]: Entering directory `/home/gvb/sourcetrees/linux/fs/vfat'
gcc -D__KERNEL__ -I/home/gvb/sourcetrees/linux/include -Wall
-Wstrict-prototypes -O2 -fomit-frame-pointer -pipe -fno-strength-reduce
-m486 -malign-loops=2 -malign-jumps=2 -malign-functions=2 -DCPU=586 -c
-o namei.o namei.c
namei.c:72: warning: initialization from incompatible pointer type
namei.c:75: warning: initialization from incompatible pointer type
namei.c:77: warning: initialization from incompatible pointer type
namei.c:915: conflicting types for `vfat_lookup'
/home/gvb/sourcetrees/linux/include/linux/msdos_fs.h:279: previous
declaration of `vfat_lookup'
namei.c:1022: conflicting types for `vfat_create'
/home/gvb/sourcetrees/linux/include/linux/msdos_fs.h:269: previous
declaration of `vfat_create'
namei.c:1275: conflicting types for `vfat_rmdir'
/home/gvb/sourcetrees/linux/include/linux/msdos_fs.h:272: previous
declaration of `vfat_rmdir'
namei.c:1315: conflicting types for `vfat_mkdir'
/home/gvb/sourcetrees/linux/include/linux/msdos_fs.h:271: previous
declaration of `vfat_mkdir'
namei.c:1344: conflicting types for `vfat_unlink'
/home/gvb/sourcetrees/linux/include/linux/msdos_fs.h:270: previous
declaration of `vfat_unlink'
namei.c:1355: conflicting types for `vfat_rename'
/home/gvb/sourcetrees/linux/include/linux/msdos_fs.h:274: previous
declaration of `vfat_rename'
namei.c:1547: warning: initialization from incompatible pointer type
namei.c:1548: warning: initialization from incompatible pointer type
namei.c:1550: warning: initialization from incompatible pointer type
namei.c:1552: warning: initialization from incompatible pointer type
namei.c:1553: warning: initialization from incompatible pointer type
namei.c:1555: warning: initialization from incompatible pointer type
namei.c:1559: warning: initialization from incompatible pointer type
make[3]: *** [namei.o] Error 1
make[3]: Leaving directory `/home/gvb/sourcetrees/linux/fs/vfat'
make[2]: *** [first_rule] Error 2
make[2]: Leaving directory `/home/gvb/sourcetrees/linux/fs/vfat'
make[1]: *** [sub_dirs] Error 2
make[1]: Leaving directory `/home/gvb/sourcetrees/linux/fs'
make: *** [linuxsubdirs] Error 2
and in umsdos (was previously posted for 2.1.46...)
make[3]: Entering directory `/home/gvb/sourcetrees/linux/fs/umsdos'
gcc -D__KERNEL__ -I/home/gvb/sourcetrees/linux/include -Wall
-Wstrict-prototypes -O2 -fomit-frame-pointer -pipe -fno-strength-reduce
-m486 -malign-loops=2 -malign-jumps=2 -malign-functions=2 -DCPU=586 -c
-o dir.o dir.c
dir.c: In function `umsdos_readdir_x':
dir.c:106: structure has no member named `s_mounted'
dir.c:110: structure has no member named `s_mounted'
dir.c: In function `umsdos_locate_path':
dir.c:568: warning: passing arg 1 of `atomic_inc' from incompatible
pointer type
dir.c:571: structure has no member named `s_mounted'
dir.c: In function `umsdos_lookup_x':
dir.c:631: warning: passing arg 1 of `atomic_inc' from incompatible
pointer type
dir.c:634: structure has no member named `s_mounted'
dir.c:642: warning: passing arg 1 of `atomic_inc' from incompatible
pointer type
dir.c:657: structure has no member named `s_mounted'
dir.c:670: structure has no member named `s_mounted'
dir.c:671: warning: passing arg 1 of `atomic_inc' from incompatible
pointer type
dir.c: In function `umsdos_hlink2inode':
dir.c:757: structure has no member named `s_mounted'
dir.c:760: warning: passing arg 1 of `atomic_inc' from incompatible
pointer type
dir.c:755: warning: `dir' might be used uninitialized in this function
dir.c: At top level:
dir.c:804: warning: initialization from incompatible pointer type
dir.c:805: warning: initialization from incompatible pointer type
dir.c:806: warning: initialization from incompatible pointer type
dir.c:807: warning: initialization from incompatible pointer type
dir.c:808: warning: initialization from incompatible pointer type
dir.c:809: warning: initialization from incompatible pointer type
dir.c:810: warning: initialization from incompatible pointer type
dir.c:811: warning: initialization from incompatible pointer type
dir.c:812: warning: initialization from incompatible pointer type
make[3]: *** [dir.o] Error 1
make[3]: Leaving directory `/home/gvb/sourcetrees/linux/fs/umsdos'
make[2]: *** [first_rule] Error 2
make[2]: Leaving directory `/home/gvb/sourcetrees/linux/fs/umsdos'
make[1]: *** [sub_dirs] Error 2
make[1]: Leaving directory `/home/gvb/sourcetrees/linux/fs'
make: *** [linuxsubdirs] Error 2