* Mike Belopuhov <m...@crypt.org.ru> [120404 17:51]:
> i agree that this is a great find. i don't really like the diff though.
> i see no point in introducing this macro. what do others think?
Your diff looks better to me.
> Index: msdosfs/denode.h
> ===================================================================
> RCS file: /cvs/src/sys/msdosfs/denode.h,v
> retrieving revision 1.23
> diff -u -p -r1.23 denode.h
> --- msdosfs/denode.h 17 Jul 2010 19:27:07 -0000 1.23
> +++ msdosfs/denode.h 4 Apr 2012 12:20:23 -0000
> @@ -116,10 +116,11 @@ struct fatcache {
> * cache is probably pretty worthless if a file is opened by multiple
> * processes.
> */
> -#define FC_SIZE 2 /* number of entries in the cache */
> +#define FC_SIZE 3 /* number of entries in the cache */
> #define FC_LASTMAP 0 /* entry the last call to pcbmap()
> resolved
> * to */
> #define FC_LASTFC 1 /* entry for the last cluster in the
> file */
> +#define FC_OLASTFC 2 /* entry for the previous last cluster
> */
>
> #define FCE_EMPTY 0xffffffff /* doesn't represent an actual
> cluster # */
>
> Index: msdosfs/msdosfs_fat.c
> ===================================================================
> RCS file: /cvs/src/sys/msdosfs/msdosfs_fat.c,v
> retrieving revision 1.22
> diff -u -p -r1.22 msdosfs_fat.c
> --- msdosfs/msdosfs_fat.c 4 Jul 2011 04:30:41 -0000 1.22
> +++ msdosfs/msdosfs_fat.c 4 Apr 2012 12:20:26 -0000
> @@ -952,6 +952,13 @@ extendfile(struct denode *dep, uint32_t
> return (error);
> }
>
> + /*
> + * Preserve value for the last cluster before extending the file
> + * to speed up further lookups.
> + */
> + fc_setcache(dep, FC_OLASTFC, dep->de_fc[FC_LASTFC].fc_frcn,
> + dep->de_fc[FC_LASTFC].fc_fsrcn);
> +
> while (count > 0) {
> /*
> * Allocate a new cluster chain and cat onto the end of the
--
Alexander Polakov | plhk.ru
