cnode.c

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/* 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_psdev.h>
#include "coda_linux.h"

static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)
{
    return memcmp(fid1, fid2, sizeof(*fid1)) == 0;
}

static const struct inode_operations coda_symlink_inode_operations = {
    .readlink   = generic_readlink,
    .follow_link    = page_follow_link_light,
    .put_link   = page_put_link,
    .setattr    = coda_setattr,
};

/* cnode.c */
static void coda_fill_inode(struct inode *inode, struct coda_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, huge_decode_dev(attr->va_rdev));
}

static int coda_test_inode(struct inode *inode, void *data)
{
    struct CodaFid *fid = (struct CodaFid *)data;
    struct coda_inode_info *cii = ITOC(inode);
    return coda_fideq(&cii->c_fid, fid);
}

static int coda_set_inode(struct inode *inode, void *data)
{
    struct CodaFid *fid = (struct CodaFid *)data;
    struct coda_inode_info *cii = ITOC(inode);
    cii->c_fid = *fid;
    return 0;
}

struct inode * coda_iget(struct super_block * sb, struct CodaFid * fid,
             struct coda_vattr * attr)
{
    struct inode *inode;
    struct coda_inode_info *cii;
    unsigned long hash = coda_f2i(fid);

    inode = iget5_locked(sb, hash, coda_test_inode, coda_set_inode, fid);

    if (!inode)
        return ERR_PTR(-ENOMEM);

    if (inode->i_state & I_NEW) {
        cii = ITOC(inode);
        /* we still need to set i_ino for things like stat(2) */
        inode->i_ino = hash;
        /* inode is locked and unique, no need to grab cii->c_lock */
        cii->c_mapcount = 0;
        unlock_new_inode(inode);
    }

    /* always replace the attributes, type might have changed */
    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
*/
struct inode *coda_cnode_make(struct CodaFid *fid, struct super_block *sb)
{
        struct coda_vattr attr;
    struct inode *inode;
        int error;
        
    /* We get inode numbers from Venus -- see venus source */
    error = venus_getattr(sb, fid, &attr);
    if (error)
        return ERR_PTR(error);

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


/* Although we treat Coda file identifiers as immutable, there is one
 * special case for files created during a disconnection where they may
 * not be globally unique. When an identifier collision is detected we
 * first try to flush the cached inode from the kernel and finally
 * resort to renaming/rehashing in-place. Userspace remembers both old
 * and new values of the identifier to handle any in-flight upcalls.
 * The real solution is to use globally unique UUIDs as identifiers, but
 * retrofitting the existing userspace code for this is non-trivial. */
void coda_replace_fid(struct inode *inode, struct CodaFid *oldfid, 
              struct CodaFid *newfid)
{
    struct coda_inode_info *cii = ITOC(inode);
    unsigned long hash = coda_f2i(newfid);
    
    BUG_ON(!coda_fideq(&cii->c_fid, oldfid));

    /* replace fid and rehash inode */
    /* XXX we probably need to hold some lock here! */
    remove_inode_hash(inode);
    cii->c_fid = *newfid;
    inode->i_ino = hash;
    __insert_inode_hash(inode, hash);
}

/* convert a fid to an inode. */
struct inode *coda_fid_to_inode(struct CodaFid *fid, struct super_block *sb) 
{
    struct inode *inode;
    unsigned long hash = coda_f2i(fid);

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

    inode = ilookup5(sb, hash, coda_test_inode, fid);
    if ( !inode )
        return NULL;

    /* we should never see newly created inodes because we intentionally
     * fail in the initialization callback */
    BUG_ON(inode->i_state & I_NEW);

    return inode;
}

/* the CONTROL inode is made without asking attributes from Venus */
struct inode *coda_cnode_makectl(struct super_block *sb)
{
    struct inode *inode = new_inode(sb);
    if (inode) {
        inode->i_ino = CTL_INO;
        inode->i_op = &coda_ioctl_inode_operations;
        inode->i_fop = &coda_ioctl_operations;
        inode->i_mode = 0444;
        return inode;
    }
    return ERR_PTR(-ENOMEM);
}