minix/servers/mfs/mount.c

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#include "fs.h"
#include "inode.h"
#include "super.h"
#include <minix/vfsif.h>
#include <minix/bdev.h>
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static int cleanmount = 1;
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/*===========================================================================*
* fs_readsuper *
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*===========================================================================*/
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int fs_readsuper()
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{
/* This function reads the superblock of the partition, gets the root inode
* and sends back the details of them. Note, that the FS process does not
* know the index of the vmnt object which refers to it, whenever the pathname
* lookup leaves a partition an ELEAVEMOUNT error is transferred back
* so that the VFS knows that it has to find the vnode on which this FS
* process' partition is mounted on.
*/
struct inode *root_ip;
cp_grant_id_t label_gid;
size_t label_len;
int r;
int readonly, isroot;
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fs_dev = (dev_t) fs_m_in.REQ_DEV;
label_gid = (cp_grant_id_t) fs_m_in.REQ_GRANT;
label_len = (size_t) fs_m_in.REQ_PATH_LEN;
readonly = (fs_m_in.REQ_FLAGS & REQ_RDONLY) ? 1 : 0;
isroot = (fs_m_in.REQ_FLAGS & REQ_ISROOT) ? 1 : 0;
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if (label_len > sizeof(fs_dev_label))
return(EINVAL);
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r = sys_safecopyfrom(fs_m_in.m_source, label_gid, (vir_bytes) 0,
(vir_bytes) fs_dev_label, label_len);
if (r != OK) {
printf("MFS %s:%d safecopyfrom failed: %d\n", __FILE__, __LINE__, r);
return(EINVAL);
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}
/* Map the driver label for this major. */
bdev_driver(fs_dev, fs_dev_label);
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/* Open the device the file system lives on. */
if (bdev_open(fs_dev, readonly ? BDEV_R_BIT : (BDEV_R_BIT|BDEV_W_BIT) ) !=
OK) {
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return(EINVAL);
}
/* Fill in the super block. */
superblock.s_dev = fs_dev; /* read_super() needs to know which dev */
r = read_super(&superblock);
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/* Is it recognized as a Minix filesystem? */
if (r != OK) {
superblock.s_dev = NO_DEV;
bdev_close(fs_dev);
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return(r);
}
/* Remember whether we were mounted cleanly so we know what to
* do at unmount time
*/
if(superblock.s_flags & MFSFLAG_CLEAN)
cleanmount = 1;
/* clean check: if rw and not clean, switch to readonly */
if(!(superblock.s_flags & MFSFLAG_CLEAN) && !readonly) {
if(bdev_close(fs_dev) != OK)
panic("couldn't bdev_close after found unclean FS");
readonly = 1;
if (bdev_open(fs_dev, BDEV_R_BIT) != OK) {
panic("couldn't bdev_open after found unclean FS");
return(EINVAL);
}
printf("MFS: WARNING: FS 0x%x unclean, mounting readonly\n", fs_dev);
}
lmfs_set_blocksize(superblock.s_block_size, major(fs_dev));
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/* Get the root inode of the mounted file system. */
if( (root_ip = get_inode(fs_dev, ROOT_INODE)) == NULL) {
printf("MFS: couldn't get root inode\n");
superblock.s_dev = NO_DEV;
bdev_close(fs_dev);
return(EINVAL);
}
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if(root_ip->i_mode == 0) {
printf("%s:%d zero mode for root inode?\n", __FILE__, __LINE__);
put_inode(root_ip);
superblock.s_dev = NO_DEV;
bdev_close(fs_dev);
return(EINVAL);
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}
superblock.s_rd_only = readonly;
superblock.s_is_root = isroot;
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/* Root inode properties */
fs_m_out.RES_INODE_NR = root_ip->i_num;
fs_m_out.RES_MODE = root_ip->i_mode;
fs_m_out.RES_FILE_SIZE_LO = root_ip->i_size;
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fs_m_out.RES_UID = root_ip->i_uid;
fs_m_out.RES_GID = root_ip->i_gid;
fs_m_out.RES_FLAGS = RES_HASPEEK;
/* Mark it dirty */
if(!superblock.s_rd_only) {
superblock.s_flags &= ~MFSFLAG_CLEAN;
if(write_super(&superblock) != OK)
panic("mounting: couldn't write dirty superblock");
}
return(r);
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}
/*===========================================================================*
* fs_mountpoint *
*===========================================================================*/
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int fs_mountpoint()
{
/* This function looks up the mount point, it checks the condition whether
* the partition can be mounted on the inode or not.
*/
register struct inode *rip;
int r = OK;
pmode_t bits;
/* Temporarily open the file. */
if( (rip = get_inode(fs_dev, (pino_t) fs_m_in.REQ_INODE_NR)) == NULL)
return(EINVAL);
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if(rip->i_mountpoint) r = EBUSY;
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/* It may not be special. */
bits = rip->i_mode & I_TYPE;
if (bits == I_BLOCK_SPECIAL || bits == I_CHAR_SPECIAL) r = ENOTDIR;
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put_inode(rip);
if(r == OK) rip->i_mountpoint = TRUE;
return(r);
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}
/*===========================================================================*
* fs_unmount *
*===========================================================================*/
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int fs_unmount()
{
/* Unmount a file system by device number. */
int count;
struct inode *rip, *root_ip;
if(superblock.s_dev != fs_dev) return(EINVAL);
/* See if the mounted device is busy. Only 1 inode using it should be
* open --the root inode-- and that inode only 1 time. */
count = 0;
for (rip = &inode[0]; rip < &inode[NR_INODES]; rip++)
if (rip->i_count > 0 && rip->i_dev == fs_dev) count += rip->i_count;
if ((root_ip = find_inode(fs_dev, ROOT_INODE)) == NULL) {
panic("MFS: couldn't find root inode\n");
return(EINVAL);
}
if (count > 1) return(EBUSY); /* can't umount a busy file system */
put_inode(root_ip);
/* force any cached blocks out of memory */
(void) fs_sync();
/* Mark it clean if we're allowed to write _and_ it was clean originally. */
if(cleanmount && !superblock.s_rd_only) {
superblock.s_flags |= MFSFLAG_CLEAN;
write_super(&superblock);
}
/* Close the device the file system lives on. */
bdev_close(fs_dev);
/* Throw out blocks out of the VM cache, to prevent corruption later. */
lmfs_invalidate(fs_dev);
/* Finish off the unmount. */
superblock.s_dev = NO_DEV;
unmountdone = TRUE;
return(OK);
}