On MFS file systems, the stat(2) call now counts indirect blocks as part of the st_blocks calculation, in addition to proper initial rounding of the file size. The returned value is now a true upper bound on the actual number of 512-byte blocks allocated to the file. As before, it is not accurate for sparse files.
158 lines
4.7 KiB
C
158 lines
4.7 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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PRIVATE 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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unsigned int zone_size, zones, sindirs, dindirs, nr_indirs, sq_indirs;
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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 = (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 = rip->i_nindirs;
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sq_indirs = nr_indirs * nr_indirs;
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sindirs = (zones - 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) * (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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PRIVATE 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 = 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), D);
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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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PUBLIC 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), D);
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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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PUBLIC 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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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), D);
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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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PUBLIC 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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