// SPDX-License-Identifier: GPL-2.0
/* 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/pagemap.h>
#include "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 = {
        .get_link       = page_get_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_nohighmem(inode);
                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);
        umode_t inode_type = coda_inode_type(attr);

retry:
        inode = iget5_locked(sb, hash, coda_test_inode, coda_set_inode, fid);
        if (!inode)
                return ERR_PTR(-ENOMEM);

        if (inode_state_read_once(inode) & 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;
                coda_fill_inode(inode, attr);
                unlock_new_inode(inode);
        } else if ((inode->i_mode & S_IFMT) != inode_type) {
                /* Inode has changed type, mark bad and grab a new one */
                remove_inode_hash(inode);
                coda_flag_inode(inode, C_PURGE);
                iput(inode);
                goto retry;
        }
        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))
                pr_warn("%s: coda_iget failed\n", __func__);
        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);

        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_state_read_once(inode) & I_NEW);

        return inode;
}

struct coda_file_info *coda_ftoc(struct file *file)
{
        struct coda_file_info *cfi = file->private_data;

        BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);

        return cfi;

}

/* 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);
}