4472b590c7
This patch changes the prefetch API so that file systems must now provide a set of block numbers, rather than a set of buffers. The result is a leaner and more well-defined API; linear computation of the range of blocks to prefetch; duplicates no longer interfering with the prefetch process; guaranteed inclusion of the block needed next into the prefetch range; and, limits and policy decisions better established by libminixfs now actually being moved into libminixfs. Change-Id: I7e44daf2d2d164bc5e2f1473ad717f3ff0f0a77f
106 lines
3.2 KiB
C
106 lines
3.2 KiB
C
#include "fs.h"
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#include <string.h>
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#include <assert.h>
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#include <sys/stat.h>
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#include <sys/statvfs.h>
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#include "inode.h"
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#include "super.h"
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/*===========================================================================*
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* estimate_blocks *
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*===========================================================================*/
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static blkcnt_t estimate_blocks(struct inode *rip)
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{
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/* Return the number of 512-byte blocks used by this file. This includes space
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* used by data zones and indirect blocks (actually also zones). Reading in all
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* indirect blocks is too costly for a stat call, so we disregard holes and
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* return a conservative estimation.
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*/
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blkcnt_t zones, sindirs, dindirs, nr_indirs, sq_indirs;
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unsigned int zone_size;
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/* Compute the number of zones used by the file. */
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zone_size = rip->i_sp->s_block_size << rip->i_sp->s_log_zone_size;
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zones = (blkcnt_t) ((rip->i_size + zone_size - 1) / zone_size);
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/* Compute the number of indirect blocks needed for that zone count. */
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nr_indirs = (blkcnt_t) rip->i_nindirs;
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sq_indirs = nr_indirs * nr_indirs;
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sindirs = (zones - (blkcnt_t) rip->i_ndzones + nr_indirs - 1) / nr_indirs;
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dindirs = (sindirs - 1 + sq_indirs - 1) / sq_indirs;
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/* Return the number of 512-byte blocks corresponding to the number of data
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* zones and indirect blocks.
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*/
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return (zones + sindirs + dindirs) * (blkcnt_t) (zone_size / 512);
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}
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/*===========================================================================*
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* fs_stat *
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*===========================================================================*/
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int fs_stat(ino_t ino_nr, struct stat *statbuf)
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{
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struct inode *rip;
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mode_t mo;
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int s;
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if ((rip = get_inode(fs_dev, ino_nr)) == NULL)
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return(EINVAL);
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/* Update the atime, ctime, and mtime fields in the inode, if need be. */
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if (rip->i_update) update_times(rip);
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/* Fill in the statbuf struct. */
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mo = rip->i_mode & I_TYPE;
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/* true iff special */
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s = (mo == I_CHAR_SPECIAL || mo == I_BLOCK_SPECIAL);
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statbuf->st_mode = (mode_t) rip->i_mode;
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statbuf->st_nlink = (nlink_t) rip->i_nlinks;
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statbuf->st_uid = rip->i_uid;
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statbuf->st_gid = rip->i_gid;
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statbuf->st_rdev = (s ? (dev_t)rip->i_zone[0] : NO_DEV);
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statbuf->st_size = rip->i_size;
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statbuf->st_atime = rip->i_atime;
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statbuf->st_mtime = rip->i_mtime;
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statbuf->st_ctime = rip->i_ctime;
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statbuf->st_blksize = lmfs_fs_block_size();
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statbuf->st_blocks = estimate_blocks(rip);
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put_inode(rip); /* release the inode */
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return(OK);
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}
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/*===========================================================================*
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* fs_statvfs *
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*===========================================================================*/
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int fs_statvfs(struct statvfs *st)
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{
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struct super_block *sp;
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int scale;
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sp = &superblock;
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scale = sp->s_log_zone_size;
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st->f_blocks = sp->s_zones;
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st->f_bfree = sp->s_zones - used_zones;
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st->f_bavail = st->f_bfree;
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st->f_bsize = sp->s_block_size << scale;
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st->f_frsize = sp->s_block_size;
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st->f_iosize = st->f_frsize;
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st->f_files = sp->s_ninodes;
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st->f_ffree = count_free_bits(sp, IMAP);
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st->f_favail = st->f_ffree;
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st->f_namemax = MFS_DIRSIZ;
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return(OK);
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}
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