3cc092ff06
now used for printing diagnostic messages through the kernel message buffer. this lets processes print diagnostics without sending messages to tty and log directly, simplifying the message protocol a lot and reducing difficulties with deadlocks and other situations in which diagnostics are blackholed (e.g. grants don't work). this makes DIAGNOSTICS(_S), ASYN_DIAGNOSTICS and DIAG_REPL obsolete, although tty and log still accept the codes for 'old' binaries. This also simplifies diagnostics in several servers and drivers - only tty needs its own kputc() now. . simplifications in vfs, and some effort to get the vnode references right (consistent) even during shutdown. m_mounted_on is now NULL for root filesystems (!) (the original and new root), a less awkward special case than 'm_mounted_on == m_root_node'. root now has exactly one reference, to root, if no files are open, just like all other filesystems. m_driver_e is unused.
568 lines
15 KiB
C
568 lines
15 KiB
C
/* This file performs the MOUNT and UMOUNT system calls.
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*
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* The entry points into this file are
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* do_mount: perform the MOUNT system call
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* do_umount: perform the UMOUNT system call
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*
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* Changes for VFS:
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* Jul 2006 (Balazs Gerofi)
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*/
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#include "fs.h"
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#include <fcntl.h>
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#include <string.h>
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#include <minix/callnr.h>
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#include <minix/com.h>
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#include <minix/keymap.h>
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#include <minix/const.h>
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#include <minix/endpoint.h>
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#include <minix/syslib.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include <dirent.h>
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#include "file.h"
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#include "fproc.h"
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#include "param.h"
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#include <minix/vfsif.h>
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#include "vnode.h"
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#include "vmnt.h"
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/* Allow the root to be replaced before the first 'real' mount. */
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PRIVATE int allow_newroot = 1;
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FORWARD _PROTOTYPE( dev_t name_to_dev, (void) );
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FORWARD _PROTOTYPE( int mount_fs, (endpoint_t fs_e) );
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/*===========================================================================*
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* do_fslogin *
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*===========================================================================*/
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PUBLIC int do_fslogin()
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{
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/* Login before mount request */
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if ((unsigned long)mount_m_in.m1_p3 != who_e) {
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last_login_fs_e = who_e;
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return SUSPEND;
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}
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/* Login after a suspended mount */
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else {
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/* Copy back original mount request message */
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m_in = mount_m_in;
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/* Set up last login FS */
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last_login_fs_e = who_e;
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/* Set up endpoint and call nr */
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who_e = m_in.m_source;
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who_p = _ENDPOINT_P(who_e);
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call_nr = m_in.m_type;
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fp = &fproc[who_p]; /* pointer to proc table struct */
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super_user = (fp->fp_effuid == SU_UID ? TRUE : FALSE); /* su? */
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return do_mount();
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}
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}
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/*===========================================================================*
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* do_mount *
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*===========================================================================*/
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PUBLIC int do_mount()
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{
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endpoint_t fs_e;
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CHECK_VREFS;
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/* Only the super-user may do MOUNT. */
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if (!super_user) return(EPERM);
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/* FS process' endpoint number */
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fs_e = (unsigned long)m_in.m1_p3;
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/* Sanity check on process number. */
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if(fs_e <= 0) {
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printf("vfs: warning: got process number %d for mount call.\n", fs_e);
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return EINVAL;
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}
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/* Do the actual job */
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return mount_fs(fs_e);
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}
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/*===========================================================================*
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* mount *
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*===========================================================================*/
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PRIVATE int mount_fs(endpoint_t fs_e)
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{
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/* Perform the mount(name, mfile, rd_only) system call. */
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int rdir, mdir; /* TRUE iff {root|mount} file is dir */
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int i, r, found, isroot, replace_root;
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struct fproc *tfp;
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struct dmap *dp;
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dev_t dev;
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message m;
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struct vnode *vp, *root_node, *mounted_on, *bspec;
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struct vmnt *vmp;
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char *label;
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struct node_details res;
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CHECK_VREFS;
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/* Only the super-user may do MOUNT. */
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if (!super_user) return(EPERM);
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/* If FS not yet logged in, save message and suspend mount */
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if (last_login_fs_e != fs_e) {
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mount_m_in = m_in;
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return SUSPEND;
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}
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/* Mount request got after FS login or
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* FS login arrived after a suspended mount */
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last_login_fs_e = NONE;
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/* Clear endpoint field */
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mount_m_in.m1_p3 = (char *) NONE;
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/* If 'name' is not for a block special file, return error. */
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if (fetch_name(m_in.name1, m_in.name1_length, M1) != OK) return(err_code);
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/* Convert name to device number */
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if ((dev = name_to_dev()) == NO_DEV) return(err_code);
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/* Check whether there is a block special file open which uses the
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* same device (partition) */
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for (bspec = &vnode[0]; bspec < &vnode[NR_VNODES]; ++bspec) {
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if (bspec->v_ref_count > 0 && bspec->v_sdev == dev) {
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/* Found, sync the buffer cache */
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req_sync(bspec->v_fs_e);
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break;
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/* Note: there are probably some blocks in the FS process' buffer
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* cache which contain data on this minor, although they will be
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* purged since the handling moves to the new FS process (if
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* everything goes well with the mount...)
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*/
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}
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}
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/* Didn't find? */
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if (bspec == &vnode[NR_VNODES] && bspec->v_sdev != dev)
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bspec = NULL;
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/* Scan vmnt table to see if dev already mounted, if not,
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* find a free slot.*/
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found = FALSE;
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vmp = NIL_VMNT;
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for (i = 0; i < NR_MNTS; ++i) {
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if (vmnt[i].m_dev == dev) {
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vmp = &vmnt[i];
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found = TRUE;
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break;
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}
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else if (!vmp && vmnt[i].m_dev == NO_DEV) {
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vmp = &vmnt[i];
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}
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}
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/* Partition was/is already mounted */
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if (found) {
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/* It is possible that we have an old root lying around that
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* needs to be remounted. */
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if (vmp->m_mounted_on || vmp->m_mounted_on == fproc[FS_PROC_NR].fp_rd) {
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/* Normally, m_mounted_on refers to the mount point. For a
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* root filesystem, m_mounted_on is equal to the root vnode.
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* We assume that the root of FS is always the real root. If
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* the two vnodes are different or if the root of FS is equal
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* to the root of the filesystem we found, we found a
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* filesystem that is in use.
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*/
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return EBUSY; /* already mounted */
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}
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if(vmp->m_mounted_on)
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panic("vfs", "root unexpectedly mounted somewhere", NO_NUM);
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if (root_dev == vmp->m_dev)
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panic("fs", "inconsistency remounting old root", NO_NUM);
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/* Now get the inode of the file to be mounted on. */
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if (fetch_name(m_in.name2, m_in.name2_length, M1) != OK) {
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return(err_code);
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}
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/* Request lookup */
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r = lookup_vp(0 /*flags*/, 0 /*!use_realuid*/, &mounted_on);
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if (r != OK) return r;
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if (vp->v_ref_count != 1)
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{
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put_vnode(vp);
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printf("vfs:mount_fs: mount point is busy\n");
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return EBUSY;
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}
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/* Issue mountpoint request */
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r = req_mountpoint(mounted_on->v_fs_e, mounted_on->v_inode_nr);
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if (r != OK)
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{
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put_vnode(mounted_on);
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printf("vfs:mount_fs: req_mountpoint_s failed with %d\n", r);
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return r;
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}
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/* Get the root inode of the mounted file system. */
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root_node = vmp->m_root_node;
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/* File types may not conflict. */
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if (r == OK) {
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mdir = ((mounted_on->v_mode & I_TYPE) == I_DIRECTORY);
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/* TRUE iff dir */
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rdir = ((root_node->v_mode & I_TYPE) == I_DIRECTORY);
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if (!mdir && rdir) r = EISDIR;
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}
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/* If error, return the mount point. */
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if (r != OK) {
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put_vnode(mounted_on);
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return(r);
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}
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/* Nothing else can go wrong. Perform the mount. */
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vmp->m_mounted_on = mounted_on;
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vmp->m_flags = m_in.rd_only;
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allow_newroot = 0; /* The root is now fixed */
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return(OK);
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}
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/* Fetch the name of the mountpoint */
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if (fetch_name(m_in.name2, m_in.name2_length, M1) != OK) {
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return(err_code);
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}
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isroot= (strcmp(user_fullpath, "/") == 0);
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replace_root= (isroot && allow_newroot);
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if (!replace_root)
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{
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/* Get mount point and inform the FS it is on. */
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#if 0
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printf("vfs:mount_fs: mount point at '%s'\n", user_fullpath);
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#endif
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r = lookup_vp(0 /*flags*/, 0 /*!use_realuid*/, &mounted_on);
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if (r != OK)
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return r;
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/* Issue mountpoint request */
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r = req_mountpoint(mounted_on->v_fs_e, mounted_on->v_inode_nr);
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if (r != OK) {
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put_vnode(mounted_on);
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printf("vfs:mount_fs: req_mountpoint_s failed with %d\n", r);
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return r;
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}
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}
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/* We'll need a vnode for the root inode, check whether there is one */
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if ((root_node = get_free_vnode(__FILE__, __LINE__)) == NIL_VNODE) {
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printf("VFSmount: no free vnode available\n");
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return ENFILE;
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}
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/* Get driver process' endpoint */
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dp = &dmap[(dev >> MAJOR) & BYTE];
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if (dp->dmap_driver == NONE) {
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printf("VFSmount: no driver for dev %x\n", dev);
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return(EINVAL);
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}
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label= dp->dmap_label;
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if (strlen(label) == 0)
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{
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panic(__FILE__, "vfs:mount_fs: no label for major", dev >> MAJOR);
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}
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#if 0
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printf("vfs:mount_fs: label = '%s'\n", label);
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#endif
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/* Issue request */
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r = req_readsuper(fs_e, label, dev, m_in.rd_only, isroot, &res);
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if (r != OK) {
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put_vnode(mounted_on);
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printf("vfs:mount_fs: req_readsuper failed with %d\n", r);
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return r;
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}
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/* Fill in root node's fields */
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root_node->v_fs_e = res.fs_e;
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root_node->v_inode_nr = res.inode_nr;
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root_node->v_mode = res.fmode;
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root_node->v_uid = res.uid;
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root_node->v_gid = res.gid;
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root_node->v_size = res.fsize;
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root_node->v_sdev = NO_DEV;
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root_node->v_fs_count = 1;
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root_node->v_ref_count = 1;
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/* Fill in max file size and blocksize for the vmnt */
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vmp->m_fs_e = res.fs_e;
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vmp->m_dev = dev;
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vmp->m_flags = m_in.rd_only;
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/* Root node is indeed on the partition */
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root_node->v_vmnt = vmp;
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root_node->v_dev = vmp->m_dev;
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if (replace_root) {
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/* Superblock and root node already read.
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* Nothing else can go wrong. Perform the mount. */
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vmp->m_root_node = root_node;
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vmp->m_mounted_on = NULL;
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root_dev = dev;
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ROOT_FS_E = fs_e;
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/* Replace all root and working directories */
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for (i= 0, tfp= fproc; i<NR_PROCS; i++, tfp++) {
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if (tfp->fp_pid == PID_FREE)
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continue;
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if (tfp->fp_rd == NULL)
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panic("fs", "do_mount: null rootdir", i);
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if (tfp->fp_wd == NULL)
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panic("fs", "do_mount: null workdir", i);
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put_vnode(tfp->fp_rd);
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dup_vnode(root_node);
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tfp->fp_rd = root_node;
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put_vnode(tfp->fp_wd);
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dup_vnode(root_node);
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tfp->fp_wd = root_node;
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}
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CHECK_VREFS;
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return(OK);
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}
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/* File types may not conflict. */
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if (r == OK) {
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mdir = ((mounted_on->v_mode & I_TYPE) == I_DIRECTORY);/* TRUE iff dir */
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rdir = ((root_node->v_mode & I_TYPE) == I_DIRECTORY);
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if (!mdir && rdir) r = EISDIR;
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}
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/* If error, return the super block and both inodes; release the vmnt. */
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if (r != OK) {
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put_vnode(mounted_on);
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put_vnode(root_node);
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vmp->m_dev = NO_DEV;
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return(r);
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}
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/* Nothing else can go wrong. Perform the mount. */
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vmp->m_mounted_on = mounted_on;
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vmp->m_root_node = root_node;
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/* The root is now fixed */
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allow_newroot = 0;
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/* There was a block spec file open, and it should be handled by the
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* new FS proc now */
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if (bspec) {
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printf("VFSmount: moving opened block spec to new FS_e: %d...\n", fs_e);
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bspec->v_bfs_e = fs_e;
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}
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CHECK_VREFS;
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return(OK);
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}
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/*===========================================================================*
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* do_umount *
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*===========================================================================*/
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PUBLIC int do_umount()
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{
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/* Perform the umount(name) system call. */
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dev_t dev;
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CHECK_VREFS;
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/* Only the super-user may do UMOUNT. */
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if (!super_user) return(EPERM);
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CHECK_VREFS;
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/* If 'name' is not for a block special file, return error. */
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if (fetch_name(m_in.name, m_in.name_length, M3) != OK) return(err_code);
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CHECK_VREFS;
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if ( (dev = name_to_dev()) == NO_DEV) return(err_code);
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CHECK_VREFS;
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return(unmount(dev));
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}
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/*===========================================================================*
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* unmount *
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*===========================================================================*/
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PUBLIC int unmount(dev)
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Dev_t dev;
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{
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struct vnode *vp, *vi;
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struct vmnt *vmp_i = NULL, *vmp = NULL;
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struct dmap *dp;
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int count, r;
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int fs_e;
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CHECK_VREFS;
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/* Find vmnt */
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for (vmp_i = &vmnt[0]; vmp_i < &vmnt[NR_MNTS]; ++vmp_i) {
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if (vmp_i->m_dev == dev) {
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if(vmp) panic(__FILE__, "device mounted more than once", dev);
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vmp = vmp_i;
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}
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}
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/* Device mounted? */
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if(!vmp)
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return EINVAL;
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/* See if the mounted device is busy. Only 1 vnode using it should be
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* open -- the root vnode -- and that inode only 1 time.
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*/
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count = 0;
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for (vp = &vnode[0]; vp < &vnode[NR_VNODES]; vp++) {
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if (vp->v_ref_count > 0 && vp->v_dev == dev) {
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#if 1
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int i;
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struct fproc *tfp;
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printf("unmount: vnode 0x%x/%d in use %d times\n",
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dev, vp->v_inode_nr, vp->v_ref_count);
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for (i= 0, tfp= fproc; i<NR_PROCS; i++, tfp++) {
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int n;
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if (tfp->fp_pid == PID_FREE)
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continue;
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if(tfp->fp_wd == vp)
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printf("\tvnode %d: wd of pid %d\n",
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vp->v_inode_nr, tfp->fp_pid);
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if(tfp->fp_rd == vp)
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printf("\tvnode %d: rd of pid %d\n",
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vp->v_inode_nr, tfp->fp_pid);
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for(n = 0; n < OPEN_MAX; n++) {
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if(tfp->fp_filp[n] && tfp->fp_filp[n]->filp_vno == vp)
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printf("\tvnode %d: fd %d of pid %d\n",
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vp->v_inode_nr, n, tfp->fp_pid);
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}
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}
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for (vmp_i = &vmnt[0]; vmp_i < &vmnt[NR_MNTS]; ++vmp_i) {
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if (vmp_i->m_dev != NO_DEV) {
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if(vmp_i->m_mounted_on == vp) {
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printf("\tvnode %d: is a mount point\n",
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vp->v_inode_nr);
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}
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if(vmp_i->m_root_node == vp) {
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printf("\tvnode %d: is a root node\n",
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vp->v_inode_nr);
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}
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}
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}
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#endif
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count += vp->v_ref_count;
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}
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}
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CHECK_VREFS;
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if (count > 1) {
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return(EBUSY); /* can't umount a busy file system */
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}
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CHECK_VREFS;
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vnode_clean_refs(vmp->m_root_node);
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CHECK_VREFS;
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if (vmp->m_mounted_on) {
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put_vnode(vmp->m_mounted_on);
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vmp->m_mounted_on->v_fs_count--;
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vmp->m_mounted_on = NIL_VNODE;
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}
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put_vnode(vmp->m_root_node);
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vmp->m_root_node->v_ref_count = 0;
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vmp->m_root_node = NIL_VNODE;
|
|
|
|
/* Request FS the unmount */
|
|
if(vmp->m_fs_e <= 0 || vmp->m_fs_e == NONE)
|
|
panic(__FILE__, "unmount: strange fs endpoint", vmp->m_fs_e);
|
|
if ((r = req_unmount(vmp->m_fs_e)) != OK) {
|
|
/* Not recoverable. */
|
|
printf("VFS: ignoring unmount failure %d from %d\n", r, vmp->m_fs_e);
|
|
}
|
|
|
|
vmp->m_dev = NO_DEV;
|
|
vmp->m_fs_e = NONE;
|
|
|
|
CHECK_VREFS;
|
|
|
|
/* Is there a block special file that was handled by that partition? */
|
|
for (vp = &vnode[0]; vp < &vnode[NR_VNODES]; vp++) {
|
|
if ((vp->v_mode & I_TYPE) == I_BLOCK_SPECIAL &&
|
|
vp->v_bfs_e == vmp->m_fs_e) {
|
|
|
|
/* Get the driver endpoint of the block spec device */
|
|
dp = &dmap[(dev >> MAJOR) & BYTE];
|
|
if (dp->dmap_driver == NONE) {
|
|
printf("VFSblock_spec_open: driver not found for device %d\n",
|
|
dev);
|
|
/* What should be done, panic??? */
|
|
continue;
|
|
}
|
|
|
|
printf("VFSunmount: moving block spec %d to root FS\n", dev);
|
|
vp->v_bfs_e = ROOT_FS_E;
|
|
|
|
/* Send the driver endpoint (even if it is known already...) */
|
|
if ((r = req_newdriver(vp->v_bfs_e, vp->v_sdev, dp->dmap_driver))
|
|
!= OK) {
|
|
printf("VFSunmount: error sending driver endpoint for block spec\n");
|
|
}
|
|
}
|
|
}
|
|
|
|
CHECK_VREFS;
|
|
|
|
return(OK);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* name_to_dev *
|
|
*===========================================================================*/
|
|
PRIVATE dev_t name_to_dev()
|
|
{
|
|
/* Convert the block special file 'path' to a device number. If 'path'
|
|
* is not a block special file, return error code in 'err_code'. */
|
|
int r;
|
|
dev_t dev;
|
|
struct vnode *vp;
|
|
|
|
/* Request lookup */
|
|
if ((r = lookup_vp(0 /*flags*/, 0 /*!use_realuid*/, &vp)) != OK) return r;
|
|
|
|
if ((vp->v_mode & I_TYPE) != I_BLOCK_SPECIAL) {
|
|
err_code = ENOTBLK;
|
|
dev= NO_DEV;
|
|
}
|
|
else
|
|
dev= vp->v_sdev;
|
|
|
|
put_vnode(vp);
|
|
|
|
return dev;
|
|
}
|
|
|