diff options
Diffstat (limited to 'fs/ufs/ufs_swab.c')
| -rw-r--r-- | fs/ufs/ufs_swab.c | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/fs/ufs/ufs_swab.c b/fs/ufs/ufs_swab.c new file mode 100644 index 000000000..2dc4061a0 --- /dev/null +++ b/fs/ufs/ufs_swab.c @@ -0,0 +1,138 @@ +/* + * linux/fs/ufs/ufs_swab.c + * + * Copyright (C) 1997 + * Francois-Rene Rideau <rideau@ens.fr> + * + */ + +/* + * For inspiration, you might wanna check sys/ufs/ffs/fs.h from whateverBSD + * + * NOTES + * 19970406 - Fare <rideau@ens.fr> + * 1) I began from old very preliminary 2.0.x sources, + * but it was underfeatured; + * I later saw that 2.1.1 sources had a *global* UFS byteswap flag. + * EVIL: imagine that a swabbed partition be mounted + * while a non-swabbed partition are active (that sucks!) + * I merged that source tree with mine. + * 2) I hope no one is using obNNUUXXIIous byteorder. + * That's the only thing I might have broken, + * though I rather think it's a fix: + * instead of __u64 like BSD, + * the former driver used an explicitly bigendian array of __u32! + * 3) I provide a few macros that use GCC C Extensions. + * Port to other compilers would require avoiding them. + * in any case, 64 bit (long long) support is required, + * unless you're ready to workaround + * 4) the swab routines below depend on the precise name and order + * of the structure elements. Watch out any modification in ufs_fs.h!!! + * 5) putting byteswapping stuff in ufs_swab* seems cleaner to me. + * 6) These sources should work with both 2.0 and 2.1 kernels... + * + * 19971013 - Fare <rideaufr@issy.cnet.fr> + * 1) Ported to 2.1.57 + * 2) instead of byteswapping, use [bl]e_to_cpu: + * it might be that we run on a VAX! + * + * HOWTO continue adding swab support: + * basically, anywhere metadata is bread() (i.e. mapped to block device), + * data should either be SWAB()ed on the fly, + * or copied to a buffer and globally bswap_ufs_*() there. + * + */ + +#include <linux/fs.h> +#include "ufs_swab.h" + +static __inline__ void n_be16_to_cpus(__u16*p,unsigned n) { +#ifndef __BIG_ENDIAN + unsigned i; + for(i=0;i<n;i++) { + be16_to_cpus(&p[i]); + } +#endif +} +static __inline__ void n_be32_to_cpus(__u32*p,unsigned n) { +#ifndef __BIG_ENDIAN + unsigned i; + for(i=0;i<n;i++) { + be32_to_cpus(&p[i]); + } +#endif +} +static __inline__ void n_le16_to_cpus(__u16*p,unsigned n) { +#ifndef __LITTLE_ENDIAN + unsigned i; + for(i=0;i<n;i++) { + le16_to_cpus(&p[i]); + } +#endif +} +static __inline__ void n_le32_to_cpus(__u32*p,unsigned n) { +#ifndef __LITTLE_ENDIAN + unsigned i; + for(i=0;i<n;i++) { + le32_to_cpus(&p[i]); + } +#endif +} + +#define __length_before(p,member) \ + ((unsigned)(((char*)&((p)->member))-(char*)(p))) +#define __length_since(p,member) \ + ((unsigned)(sizeof(*p)-__length_before(p,member))) +#define __length_between(p,begin,after_end) \ + ((unsigned)(__length_before(p,after_end)-__length_before(p,begin))) +#define be32_to_cpus__between(s,begin,after_end) \ + n_be32_to_cpus((__u32*)&((s).begin), \ + __length_between(&s,begin,after_end)/4) +#define le32_to_cpus__between(s,begin,after_end) \ + n_le32_to_cpus((__u32*)&((s).begin), \ + __length_between(&s,begin,after_end)/4) +#define be32_to_cpus__since(s,begin) \ + n_be32_to_cpus((__u32*)&((s).begin), \ + __length_since(&s,begin)/4) +#define le32_to_cpus__since(s,begin) \ + n_le32_to_cpus((__u32*)&((s).begin), \ + __length_since(&s,begin)/4) +#define be16_to_cpus__between(s,begin,after_end) \ + n_be16_to_cpus((__u16*)&((s).begin), \ + __length_between(&s,begin,after_end)/2) +#define le16_to_cpus__between(s,begin,after_end) \ + n_le16_to_cpus((__u16*)&((s).begin), \ + __length_between(&s,begin,after_end)/2) + +/* + * Here are the whole-structure swabping routines... + */ + +extern void ufs_superblock_be_to_cpus(struct ufs_superblock * usb) { +#ifndef __BIG_ENDIAN + be32_to_cpus__between(*usb,fs_link,fs_fmod); + /* XXX - I dunno what to do w/ fs_csp, + * but it is unused by the current code, so that's ok for now. + */ + be32_to_cpus(&usb->fs_cpc); + be16_to_cpus__between(*usb,fs_opostbl,fs_sparecon); + be32_to_cpus__between(*usb,fs_sparecon,fs_qbmask); + be64_to_cpus(&usb->fs_qbmask); + be64_to_cpus(&usb->fs_qfmask); + be32_to_cpus__between(*usb,fs_postblformat,fs_magic); +#endif +} +extern void ufs_superblock_le_to_cpus(struct ufs_superblock * usb) { +#ifndef __LITTLE_ENDIAN + le32_to_cpus__between(*usb,fs_link,fs_fmod); + /* XXX - I dunno what to do w/ fs_csp, + * but it is unused by the current code, so that's ok for now. + */ + le32_to_cpus(&usb->fs_cpc); + le16_to_cpus__between(*usb,fs_opostbl,fs_sparecon); + le32_to_cpus__between(*usb,fs_sparecon,fs_qbmask); + le64_to_cpus(&usb->fs_qbmask); + le64_to_cpus(&usb->fs_qfmask); + le32_to_cpus__between(*usb,fs_postblformat,fs_magic); +#endif +} |