614 lines
17 KiB
C
614 lines
17 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_fsready: perform the FS_READY system call
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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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* unmount: unmount a file system
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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 <minix/bitmap.h>
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#include <minix/ds.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include <sys/mount.h>
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#include <dirent.h>
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#include <assert.h>
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#include "file.h"
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#include "fproc.h"
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#include "dmap.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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#include "path.h"
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#include "param.h"
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/* Allow the root to be replaced before the first 'real' mount. */
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PRIVATE int have_root = 0;
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/* Bitmap of in-use "none" pseudo devices. */
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PRIVATE bitchunk_t nonedev[BITMAP_CHUNKS(NR_NONEDEVS)] = { 0 };
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#define alloc_nonedev(dev) SET_BIT(nonedev, minor(dev) - 1)
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#define free_nonedev(dev) UNSET_BIT(nonedev, minor(dev) - 1)
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FORWARD _PROTOTYPE( dev_t name_to_dev, (int allow_mountpt,
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char path[PATH_MAX]) );
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FORWARD _PROTOTYPE( dev_t find_free_nonedev, (void) );
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FORWARD _PROTOTYPE( void update_bspec, (dev_t dev, endpoint_t fs_e,
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int send_drv_e) );
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/*===========================================================================*
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* update_bspec *
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*===========================================================================*/
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PRIVATE void update_bspec(dev_t dev, endpoint_t fs_e, int send_drv_e)
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{
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/* Update all block special files for a certain device, to use a new FS endpt
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* to route raw block I/O requests through.
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*/
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struct vnode *vp;
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struct dmap *dp;
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int r, major;
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for (vp = &vnode[0]; vp < &vnode[NR_VNODES]; ++vp)
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if (vp->v_ref_count > 0 && S_ISBLK(vp->v_mode) && vp->v_sdev == dev) {
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vp->v_bfs_e = fs_e;
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if (send_drv_e) {
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major = major(dev);
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if (major < 0 || major >= NR_DEVICES) {
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/* Can't update for out-of-range major */
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continue;
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}
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dp = &dmap[major(dev)];
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if (dp->dmap_driver == NONE) {
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/* Can't update for vanished driver */
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printf("VFS: can't send new driver label\n");
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continue;
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}
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if ((r = req_newdriver(fs_e, vp->v_sdev,
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dp->dmap_label)) != OK) {
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printf("VFS: Failed to send new driver label"
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" for moved block special file to %d\n",
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fs_e);
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}
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}
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}
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}
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/*===========================================================================*
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* do_fsready *
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*===========================================================================*/
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PUBLIC int do_fsready()
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{
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/* deprecated */
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return(SUSPEND);
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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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/* Perform the mount(name, mfile, mount_flags) system call. */
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endpoint_t fs_e;
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int r, slot, rdonly, nodev;
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char fullpath[PATH_MAX];
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char mount_label[LABEL_MAX];
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dev_t dev;
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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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if (m_in.mount_flags & MS_LABEL16) {
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/* Get the label from the caller, and ask DS for the endpoint. */
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r = sys_datacopy(who_e, (vir_bytes) m_in.fs_label, SELF,
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(vir_bytes) mount_label, (phys_bytes) sizeof(mount_label));
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if (r != OK) return(r);
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mount_label[sizeof(mount_label)-1] = 0;
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r = ds_retrieve_label_endpt(mount_label, &fs_e);
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if (r != OK) return(r);
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} else {
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/* Legacy support: get the endpoint from the request itself. */
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fs_e = (endpoint_t) m_in.fs_label;
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mount_label[0] = 0;
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}
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/* Sanity check on process number. */
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if (isokendpt(fs_e, &slot) != OK) return(EINVAL);
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/* Should the file system be mounted read-only? */
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rdonly = (m_in.mount_flags & MS_RDONLY);
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/* A null string for block special device means don't use a device at all. */
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nodev = (m_in.name1_length == 0);
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if (!nodev) {
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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, fullpath) != OK)
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return(err_code);
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if ((dev = name_to_dev(FALSE /*allow_mountpt*/, fullpath)) == NO_DEV)
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return(err_code);
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} else {
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/* Find a free pseudo-device as substitute for an actual device. */
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if ((dev = find_free_nonedev()) == NO_DEV)
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return(err_code);
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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, fullpath) != OK)
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return(err_code);
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/* Do the actual job */
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return mount_fs(dev, fullpath, fs_e, rdonly, mount_label);
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}
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/*===========================================================================*
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* mount_fs *
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*===========================================================================*/
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PUBLIC int mount_fs(
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dev_t dev,
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char mountpoint[PATH_MAX],
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endpoint_t fs_e,
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int rdonly,
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char mount_label[LABEL_MAX] )
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{
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int rdir, mdir; /* TRUE iff {root|mount} file is dir */
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int i, r = OK, found, isroot, mount_root, con_reqs, slot;
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struct fproc *tfp, *rfp;
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struct dmap *dp;
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struct vnode *root_node, *vp = NULL;
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struct vmnt *new_vmp, *parent_vmp;
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char *label;
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struct node_details res;
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struct lookup resolve;
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/* Look up block device driver label when dev is not a pseudo-device */
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label = "";
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if (!is_nonedev(dev)) {
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/* Get driver process' endpoint */
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dp = &dmap[major(dev)];
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if (dp->dmap_driver == NONE) {
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printf("VFS: no driver for dev %d\n", dev);
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return(EINVAL);
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}
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label = dp->dmap_label;
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assert(strlen(label) > 0);
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}
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/* Scan vmnt table to see if dev already mounted. If not, find a free slot.*/
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found = FALSE;
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for (i = 0; i < NR_MNTS; ++i) {
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if (vmnt[i].m_dev == dev) found = TRUE;
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}
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if (found) {
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return(EBUSY);
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} else if ((new_vmp = get_free_vmnt()) == NULL) {
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return(ENOMEM);
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}
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if ((r = lock_vmnt(new_vmp, VMNT_EXCL)) != OK) return(r);
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isroot = (strcmp(mountpoint, "/") == 0);
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mount_root = (isroot && have_root < 2); /* Root can be mounted twice:
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* 1: ramdisk
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* 2: boot disk (e.g., harddisk)
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*/
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if (!mount_root) {
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/* Get vnode of mountpoint */
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lookup_init(&resolve, mountpoint, PATH_NOFLAGS, &parent_vmp, &vp);
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resolve.l_vmnt_lock = VMNT_EXCL;
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resolve.l_vnode_lock = VNODE_WRITE;
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if ((vp = eat_path(&resolve, fp)) == NULL)
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r = err_code;
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else if (vp->v_ref_count == 1) {
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/*Tell FS on which vnode it is mounted (glue into mount tree)*/
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r = req_mountpoint(vp->v_fs_e, vp->v_inode_nr);
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} else
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r = EBUSY;
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if (vp != NULL) {
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/* Quickly unlock to allow back calls (from e.g. FUSE) to
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* relock */
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unlock_vmnt(parent_vmp);
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}
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if (r != OK) {
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if (vp != NULL) {
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unlock_vnode(vp);
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put_vnode(vp);
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}
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unlock_vmnt(new_vmp);
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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 */
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if ((root_node = get_free_vnode()) == NULL) {
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if (vp != NULL) {
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unlock_vnode(vp);
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put_vnode(vp);
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}
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unlock_vmnt(new_vmp);
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return(err_code);
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}
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lock_vnode(root_node, VNODE_OPCL);
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/* Record process as a system process */
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if (isokendpt(fs_e, &slot) != OK) {
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if (vp != NULL) {
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unlock_vnode(vp);
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put_vnode(vp);
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}
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unlock_vnode(root_node);
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unlock_vmnt(new_vmp);
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return(EINVAL);
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}
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rfp = &fproc[slot];
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rfp->fp_flags |= FP_SYS_PROC; /* Process is an FS */
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/* Store some essential vmnt data first */
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new_vmp->m_fs_e = fs_e;
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new_vmp->m_dev = dev;
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if (rdonly) new_vmp->m_flags |= VMNT_READONLY;
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else new_vmp->m_flags &= ~VMNT_READONLY;
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/* Tell FS which device to mount */
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new_vmp->m_flags |= VMNT_MOUNTING;
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r = req_readsuper(fs_e, label, dev, rdonly, isroot, &res, &con_reqs);
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new_vmp->m_flags &= ~VMNT_MOUNTING;
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if (r != OK) {
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new_vmp->m_fs_e = NONE;
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new_vmp->m_dev = NO_DEV;
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unlock_vnode(root_node);
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if (vp != NULL) {
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unlock_vnode(vp);
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put_vnode(vp);
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}
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unlock_vmnt(new_vmp);
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return(r);
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}
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lock_bsf();
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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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/* Root node is indeed on the partition */
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root_node->v_vmnt = new_vmp;
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root_node->v_dev = new_vmp->m_dev;
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if (con_reqs == 0)
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new_vmp->m_comm.c_max_reqs = 1; /* Default if FS doesn't tell us */
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else
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new_vmp->m_comm.c_max_reqs = con_reqs;
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new_vmp->m_comm.c_cur_reqs = 0;
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if (mount_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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new_vmp->m_root_node = root_node;
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new_vmp->m_mounted_on = NULL;
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strcpy(new_vmp->m_label, mount_label);
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if (is_nonedev(dev)) alloc_nonedev(dev);
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update_bspec(dev, fs_e, 0 /* Don't send new driver endpoint */);
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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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#define MAKEROOT(what) { \
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if (what) put_vnode(what); \
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dup_vnode(root_node); \
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what = root_node; \
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}
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MAKEROOT(tfp->fp_rd);
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MAKEROOT(tfp->fp_wd);
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}
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unlock_vnode(root_node);
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unlock_vmnt(new_vmp);
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have_root++; /* We have a (new) root */
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unlock_bsf();
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return(OK);
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}
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/* File types may not conflict. */
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mdir = ((vp->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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/* If error, return the super block and both inodes; release the vmnt. */
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if (r != OK) {
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unlock_vnode(vp);
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unlock_vnode(root_node);
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unlock_vmnt(new_vmp);
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put_vnode(vp);
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put_vnode(root_node);
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new_vmp->m_dev = NO_DEV;
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new_vmp->m_flags = 0;
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unlock_bsf();
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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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new_vmp->m_mounted_on = vp;
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new_vmp->m_root_node = root_node;
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strcpy(new_vmp->m_label, mount_label);
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/* Allocate the pseudo device that was found, if not using a real device. */
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if (is_nonedev(dev)) alloc_nonedev(dev);
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/* The new FS will handle block I/O requests for its device now. */
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if (!(new_vmp->m_flags & VMNT_FORCEROOTBSF))
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update_bspec(dev, fs_e, 0 /* Don't send new driver endpoint */);
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unlock_vnode(vp);
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unlock_vnode(root_node);
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unlock_vmnt(new_vmp);
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unlock_bsf();
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return(OK);
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}
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/*===========================================================================*
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* mount_pfs *
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*===========================================================================*/
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PUBLIC void mount_pfs(void)
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{
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/* Mount the Pipe File Server. It's not really mounted onto the file system,
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but it's necessary it has a vmnt entry to make locking easier */
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dev_t dev;
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struct vmnt *vmp;
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struct fproc *rfp;
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if ((dev = find_free_nonedev()) == NO_DEV)
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panic("VFS: no nonedev to initialize PFS");
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if ((vmp = get_free_vmnt()) == NULL)
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panic("VFS: no vmnt to initialize PFS");
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alloc_nonedev(dev);
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vmp->m_dev = dev;
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vmp->m_fs_e = PFS_PROC_NR;
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strcpy(vmp->m_label, "pfs");
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rfp = &fproc[_ENDPOINT_P(PFS_PROC_NR)];
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rfp->fp_flags |= FP_SYS_PROC; /* PFS is a driver and an FS */
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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(void)
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{
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/* Perform the umount(name) system call. */
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char label[LABEL_MAX];
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dev_t dev;
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int r;
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char fullpath[PATH_MAX];
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/* Only the super-user may do umount. */
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if (!super_user) return(EPERM);
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/* If 'name' is not for a block special file or mountpoint, return error. */
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if (fetch_name(m_in.name, m_in.name_length, M3, fullpath) != OK)
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return(err_code);
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if ((dev = name_to_dev(TRUE /*allow_mountpt*/, fullpath)) == NO_DEV)
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return(err_code);
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if ((r = unmount(dev, label)) != OK) return(r);
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/* Return the label of the mounted file system, so that the caller
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* can shut down the corresponding server process.
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*/
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if (strlen(label) >= M3_LONG_STRING) /* should never evaluate to true */
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label[M3_LONG_STRING-1] = 0;
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strcpy(m_out.umount_label, label);
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return(OK);
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}
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/*===========================================================================*
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* unmount *
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*===========================================================================*/
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PUBLIC int unmount(
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dev_t dev, /* block-special device */
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char *label /* buffer to retrieve label, or NULL */
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)
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{
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struct vnode *vp;
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struct vmnt *vmp_i = NULL, *vmp = NULL;
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int count, locks, r;
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/* Find vmnt that is to be unmounted */
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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("device mounted more than once: %d", dev);
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vmp = vmp_i;
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}
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}
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/* Did we find the vmnt (i.e., was dev a mounted device)? */
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if(!vmp) return(EINVAL);
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if ((r = lock_vmnt(vmp, VMNT_EXCL)) != OK) return(r);
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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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locks = 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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count += vp->v_ref_count;
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if (is_vnode_locked(vp)) locks++;
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}
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if (count > 1 || locks > 1 || tll_haspendinglock(&vmp->m_lock)) {
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unlock_vmnt(vmp);
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return(EBUSY); /* can't umount a busy file system */
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}
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/* Tell FS to drop all inode references for root inode except 1. */
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vnode_clean_refs(vmp->m_root_node);
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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 = NULL;
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}
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vmp->m_comm.c_max_reqs = 1; /* Force max concurrent reqs to just one, so
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* we won't send any messages after the
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* unmount request */
|
|
|
|
/* Tell FS to unmount */
|
|
if ((r = req_unmount(vmp->m_fs_e)) != OK) /* Not recoverable. */
|
|
printf("VFS: ignoring failed umount attempt FS endpoint: %d (%d)\n",
|
|
vmp->m_fs_e, r);
|
|
|
|
if (is_nonedev(vmp->m_dev)) free_nonedev(vmp->m_dev);
|
|
|
|
if (label != NULL) strcpy(label, vmp->m_label);
|
|
|
|
if (vmp->m_root_node) { /* PFS lacks a root node */
|
|
vmp->m_root_node->v_ref_count = 0;
|
|
vmp->m_root_node->v_fs_count = 0;
|
|
vmp->m_root_node->v_sdev = NO_DEV;
|
|
vmp->m_root_node = NULL;
|
|
}
|
|
vmp->m_dev = NO_DEV;
|
|
vmp->m_fs_e = NONE;
|
|
|
|
unlock_vmnt(vmp);
|
|
|
|
/* The root FS will handle block I/O requests for this device now. */
|
|
lock_bsf();
|
|
update_bspec(dev, ROOT_FS_E, 1 /* send new driver endpoint */);
|
|
unlock_bsf();
|
|
|
|
return(OK);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* unmount_all *
|
|
*===========================================================================*/
|
|
PUBLIC void unmount_all(void)
|
|
{
|
|
/* Unmount all filesystems. File systems are mounted on other file systems,
|
|
* so you have to pull off the loose bits repeatedly to get it all undone.
|
|
*/
|
|
|
|
int i;
|
|
struct vmnt *vmp;
|
|
|
|
/* Now unmount the rest */
|
|
for (i = 0; i < NR_MNTS; i++) {
|
|
/* Unmount at least one. */
|
|
for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; vmp++) {
|
|
if (vmp->m_dev != NO_DEV)
|
|
unmount(vmp->m_dev, NULL);
|
|
}
|
|
}
|
|
check_vnode_locks();
|
|
check_vmnt_locks();
|
|
check_filp_locks();
|
|
check_bsf_lock();
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* name_to_dev *
|
|
*===========================================================================*/
|
|
PRIVATE dev_t name_to_dev(int allow_mountpt, char path[PATH_MAX])
|
|
{
|
|
/* Convert the block special file in 'user_fullpath' to a device number.
|
|
* If the given path is not a block special file, but 'allow_mountpt' is set
|
|
* and the path is the root node of a mounted file system, return that device
|
|
* number. In all other cases, return NO_DEV and an error code in 'err_code'.
|
|
*/
|
|
dev_t dev;
|
|
struct vnode *vp;
|
|
struct vmnt *vmp;
|
|
struct lookup resolve;
|
|
|
|
lookup_init(&resolve, path, PATH_NOFLAGS, &vmp, &vp);
|
|
resolve.l_vmnt_lock = VMNT_READ;
|
|
resolve.l_vnode_lock = VNODE_READ;
|
|
|
|
/* Request lookup */
|
|
if ((vp = eat_path(&resolve, fp)) == NULL) return(NO_DEV);
|
|
|
|
if ((vp->v_mode & I_TYPE) == I_BLOCK_SPECIAL) {
|
|
dev = vp->v_sdev;
|
|
} else if (allow_mountpt && vp->v_vmnt->m_root_node == vp) {
|
|
dev = vp->v_dev;
|
|
} else {
|
|
err_code = ENOTBLK;
|
|
dev = NO_DEV;
|
|
}
|
|
|
|
unlock_vnode(vp);
|
|
unlock_vmnt(vmp);
|
|
put_vnode(vp);
|
|
return(dev);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* is_nonedev *
|
|
*===========================================================================*/
|
|
PUBLIC int is_nonedev(dev_t dev)
|
|
{
|
|
/* Return whether the given device is a "none" pseudo device.
|
|
*/
|
|
|
|
return (major(dev) == NONE_MAJOR &&
|
|
minor(dev) > 0 && minor(dev) <= NR_NONEDEVS);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* find_free_nonedev *
|
|
*===========================================================================*/
|
|
PRIVATE dev_t find_free_nonedev(void)
|
|
{
|
|
/* Find a free "none" pseudo device. Do not allocate it yet.
|
|
*/
|
|
int i;
|
|
|
|
for (i = 0; i < NR_NONEDEVS; i++)
|
|
if (!GET_BIT(nonedev, i))
|
|
return makedev(NONE_MAJOR, i + 1);
|
|
|
|
err_code = EMFILE;
|
|
return NO_DEV;
|
|
}
|