bd3cde4571
Add primary cache management feature to libminixfs as mfs and ext2
currently do separately, remove cache code from mfs and ext2, and make
them use the libminixfs interface. This makes all fields of the buf
struct private to libminixfs and FS clients aren't supposed to access
them at all. Only the opaque 'void *data' field (the FS block contents,
used to be called bp) is to be accessed by the FS client.
The main purpose is to implement the interface to the 2ndary vm cache
just once, get rid of some code duplication, and add a little
abstraction to reduce the code inertia of the whole caching business.
Some minor sanity checking and prohibition done by mfs in this code
as removed from the generic primary cache code as a result:
- checking all inodes are not in use when allocating/resizing
the cache
- checking readonly filesystems aren't written to
- checking the superblock isn't written to on mounted filesystems
The minixfslib code relies on fs_blockstats() in the client filesystem to
return some FS usage information.
160 lines
4.8 KiB
C
160 lines
4.8 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/statfs.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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#include <minix/vfsif.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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* stat_inode *
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*===========================================================================*/
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static int stat_inode(
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register struct inode *rip, /* pointer to inode to stat */
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endpoint_t who_e, /* Caller endpoint */
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cp_grant_id_t gid /* grant for the stat buf */
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)
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{
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/* Common code for stat and fstat system calls. */
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struct stat statbuf;
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mode_t mo;
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int r, s;
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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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memset(&statbuf, 0, sizeof(struct stat));
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statbuf.st_dev = rip->i_dev;
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statbuf.st_ino = rip->i_num;
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statbuf.st_mode = rip->i_mode;
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statbuf.st_nlink = 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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/* Copy the struct to user space. */
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r = sys_safecopyto(who_e, gid, (vir_bytes) 0, (vir_bytes) &statbuf,
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(size_t) sizeof(statbuf));
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return(r);
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}
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/*===========================================================================*
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* fs_fstatfs *
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*===========================================================================*/
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int fs_fstatfs()
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{
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struct statfs st;
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struct inode *rip;
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int r;
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if((rip = find_inode(fs_dev, ROOT_INODE)) == NULL)
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return(EINVAL);
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st.f_bsize = rip->i_sp->s_block_size;
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/* Copy the struct to user space. */
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r = sys_safecopyto(fs_m_in.m_source, (cp_grant_id_t) fs_m_in.REQ_GRANT,
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(vir_bytes) 0, (vir_bytes) &st, (size_t) sizeof(st));
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return(r);
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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()
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{
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struct statvfs st;
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struct super_block *sp;
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int r, scale;
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u32_t used;
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sp = get_super(fs_dev);
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scale = sp->s_log_zone_size;
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fs_blockstats((u32_t *) &st.f_blocks, (u32_t *) &st.f_bfree, &used);
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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_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_fsid = fs_dev;
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st.f_flag = (sp->s_rd_only == 1 ? ST_RDONLY : 0);
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st.f_namemax = MFS_DIRSIZ;
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/* Copy the struct to user space. */
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r = sys_safecopyto(fs_m_in.m_source, fs_m_in.REQ_GRANT, 0, (vir_bytes) &st,
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(phys_bytes) sizeof(st));
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return(r);
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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()
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{
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register int r; /* return value */
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register struct inode *rip; /* target inode */
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if ((rip = get_inode(fs_dev, (ino_t) fs_m_in.REQ_INODE_NR)) == NULL)
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return(EINVAL);
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r = stat_inode(rip, fs_m_in.m_source, (cp_grant_id_t) fs_m_in.REQ_GRANT);
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put_inode(rip); /* release the inode */
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return(r);
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}
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