cnode.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

/* cnode related routines for the coda kernel code
   (C) 1996 Peter Braam
   */

#include <linux/types.h>
#include <linux/string.h>
#include <linux/time.h>

#include <linux/coda.h>
#include <linux/coda_linux.h>
#include <linux/coda_fs_i.h>
#include <linux/coda_psdev.h>

extern int coda_debug;
extern int coda_print_entry;

inline int coda_fideq(ViceFid *fid1, ViceFid *fid2)
{
	if (fid1->Vnode != fid2->Vnode)
		return 0;
	if (fid1->Volume != fid2->Volume)
		return 0;
	if (fid1->Unique != fid2->Unique)
		return 0;
	return 1;
}

static struct inode_operations coda_symlink_inode_operations = {
	readlink:	page_readlink,
	follow_link:	page_follow_link,
	setattr:	coda_notify_change,
};

/* cnode.c */
static void coda_fill_inode(struct inode *inode, struct coda_vattr *attr)
{
        CDEBUG(D_SUPER, "ino: %ld\n", inode->i_ino);

        if (coda_debug & D_SUPER ) 
		print_vattr(attr);

        coda_vattr_to_iattr(inode, attr);

        if (S_ISREG(inode->i_mode)) {
                inode->i_op = &coda_file_inode_operations;
                inode->i_fop = &coda_file_operations;
        } else if (S_ISDIR(inode->i_mode)) {
                inode->i_op = &coda_dir_inode_operations;
                inode->i_fop = &coda_dir_operations;
        } else if (S_ISLNK(inode->i_mode)) {
		inode->i_op = &coda_symlink_inode_operations;
		inode->i_data.a_ops = &coda_symlink_aops;
		inode->i_mapping = &inode->i_data;
	} else
                init_special_inode(inode, inode->i_mode, attr->va_rdev);
}

struct inode * coda_iget(struct super_block * sb, ViceFid * fid,
			 struct coda_vattr * attr)
{
	struct inode *inode;
	struct coda_inode_info *cii;
	ino_t ino = attr->va_fileid;

	inode = iget(sb, ino);
	if ( !inode ) { 
		CDEBUG(D_CNODE, "coda_iget: no inode\n");
		return ERR_PTR(-ENOMEM);
	}

	/* check if the inode is already initialized */
	cii = ITOC(inode);
	if (cii->c_fid.Volume != 0 || cii->c_fid.Vnode != 0 || cii->c_fid.Unique != 0) {
		/* see if it is the right one (might have an inode collision) */
		if ( !coda_fideq(fid, &cii->c_fid) ) {
			printk("coda_iget: initialized inode old %s new %s!\n",
					coda_f2s(&cii->c_fid), coda_f2s2(fid));
			iput(inode);
			return ERR_PTR(-ENOENT);
		}
		/* we will still replace the attributes, type might have changed */
		goto out;
	}

	/* new, empty inode found... initializing */

	/* Initialize the Coda inode info structure */
	cii->c_fid   = *fid;
	cii->c_vnode = inode;

out:
	coda_fill_inode(inode, attr);
	return inode;
}

/* this is effectively coda_iget:
   - get attributes (might be cached)
   - get the inode for the fid using vfs iget
   - link the two up if this is needed
   - fill in the attributes
*/
int coda_cnode_make(struct inode **inode, ViceFid *fid, struct super_block *sb)
{
        struct coda_vattr attr;
        int error;
        
        ENTRY;

	/* We get inode numbers from Venus -- see venus source */

	error = venus_getattr(sb, fid, &attr);
	if ( error ) {
	    CDEBUG(D_CNODE, 
		   "coda_cnode_make: coda_getvattr returned %d for %s.\n", 
		   error, coda_f2s(fid));
	    *inode = NULL;
	    EXIT;
	    return error;
	} 

	*inode = coda_iget(sb, fid, &attr);
	if ( IS_ERR(*inode) ) {
		printk("coda_cnode_make: coda_iget failed\n");
		EXIT;
                return PTR_ERR(*inode);
        }

	CDEBUG(D_DOWNCALL, "Done making inode: ino %ld, count %d with %s\n",
		(*inode)->i_ino, atomic_read(&(*inode)->i_count), 
		coda_f2s(&(*inode)->u.coda_i.c_fid));
        EXIT;
	return 0;
}


void coda_replace_fid(struct inode *inode, struct ViceFid *oldfid, 
		      struct ViceFid *newfid)
{
	struct coda_inode_info *cii;
	
	cii = ITOC(inode);

	if ( ! coda_fideq(&cii->c_fid, oldfid) )
		printk("What? oldfid != cii->c_fid. Call 911.\n");

	cii->c_fid = *newfid;
}


 

/* convert a fid to an inode. Mostly we can compute
   the inode number from the FID, but not for volume
   mount points: those are in a list */
struct inode *coda_fid_to_inode(ViceFid *fid, struct super_block *sb) 
{
	ino_t nr;
	struct inode *inode;
	struct coda_inode_info *cii;
	ENTRY;

	if ( !sb ) {
		printk("coda_fid_to_inode: no sb!\n");
		return NULL;
	}

	CDEBUG(D_INODE, "%s\n", coda_f2s(fid));


        /* weird fids cannot be hashed, have to look for them the hard way */
	if ( coda_fid_is_weird(fid) ) {
		struct coda_sb_info *sbi = coda_sbp(sb);
		struct list_head *le;

                list_for_each(le, &sbi->sbi_cihead)
                {
			cii = list_entry(le, struct coda_inode_info, c_cilist);
			if ( cii->c_magic != CODA_CNODE_MAGIC ) BUG();

			CDEBUG(D_DOWNCALL, "iterating, now doing %s, ino %ld\n",
			       coda_f2s(&cii->c_fid), cii->c_vnode->i_ino);

			if ( coda_fideq(&cii->c_fid, fid) ) {
				inode = cii->c_vnode;
				CDEBUG(D_INODE, "volume root, found %ld\n", inode->i_ino);
				iget(sb, inode->i_ino);
				return inode;
			}
		}
		return NULL;
	}

	/* fid is not weird: ino should be computable */
	nr = coda_f2i(fid);
	inode = iget(sb, nr);
	if ( !inode ) {
		printk("coda_fid_to_inode: null from iget, sb %p, nr %ld.\n",
		       sb, (long)nr);
		return NULL;
	}

	/* check if this inode is linked to a cnode */
	cii = ITOC(inode);

	/* make sure this is the one we want */
	if ( coda_fideq(fid, &cii->c_fid) ) {
                CDEBUG(D_INODE, "found %ld\n", inode->i_ino);
                return inode;
        }

#if 0
        printk("coda_fid2inode: bad cnode (ino %ld, fid %s)", nr, coda_f2s(fid));
#endif
        iput(inode);
        return NULL;

}

/* the CONTROL inode is made without asking attributes from Venus */
int coda_cnode_makectl(struct inode **inode, struct super_block *sb)
{
    int error = 0;

    *inode = iget(sb, CTL_INO);
    if ( *inode ) {
	(*inode)->i_op = &coda_ioctl_inode_operations;
	(*inode)->i_fop = &coda_ioctl_operations;
	(*inode)->i_mode = 0444;
	error = 0;
    } else { 
	error = -ENOMEM;
    }
    
    return error;
}