Linux v2.6.15-rc7

[pohmelfs.git] / fs / coda / dir.c

/*
 * Directory operations for Coda filesystem
 * Original version: (C) 1996 P. Braam and M. Callahan
 * Rewritten for Linux 2.1. (C) 1997 Carnegie Mellon University
 * 
 * Carnegie Mellon encourages users to contribute improvements to
 * the Coda project. Contact Peter Braam (coda@cs.cmu.edu).
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/smp_lock.h>

#include <asm/uaccess.h>

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

/* dir inode-ops */
static int coda_create(struct inode *dir, struct dentry *new, int mode, struct nameidata *nd);
static struct dentry *coda_lookup(struct inode *dir, struct dentry *target, struct nameidata *nd);
static int coda_link(struct dentry *old_dentry, struct inode *dir_inode, 
                     struct dentry *entry);
static int coda_unlink(struct inode *dir_inode, struct dentry *entry);
static int coda_symlink(struct inode *dir_inode, struct dentry *entry,
                        const char *symname);
static int coda_mkdir(struct inode *dir_inode, struct dentry *entry, int mode);
static int coda_rmdir(struct inode *dir_inode, struct dentry *entry);
static int coda_rename(struct inode *old_inode, struct dentry *old_dentry, 
                       struct inode *new_inode, struct dentry *new_dentry);

/* dir file-ops */
static int coda_readdir(struct file *file, void *dirent, filldir_t filldir);

/* dentry ops */
static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd);
static int coda_dentry_delete(struct dentry *);

/* support routines */
static int coda_venus_readdir(struct file *filp, filldir_t filldir,
                              void *dirent, struct dentry *dir);
int coda_fsync(struct file *, struct dentry *dentry, int datasync);

/* same as fs/bad_inode.c */
static int coda_return_EIO(void)
{
        return -EIO;
}
#define CODA_EIO_ERROR ((void *) (coda_return_EIO))

static struct dentry_operations coda_dentry_operations =
{
        .d_revalidate   = coda_dentry_revalidate,
        .d_delete       = coda_dentry_delete,
};

struct inode_operations coda_dir_inode_operations =
{
        .create         = coda_create,
        .lookup         = coda_lookup,
        .link           = coda_link,
        .unlink         = coda_unlink,
        .symlink        = coda_symlink,
        .mkdir          = coda_mkdir,
        .rmdir          = coda_rmdir,
        .mknod          = CODA_EIO_ERROR,
        .rename         = coda_rename,
        .permission     = coda_permission,
        .getattr        = coda_getattr,
        .setattr        = coda_setattr,
};

struct file_operations coda_dir_operations = {
        .llseek         = generic_file_llseek,
        .read           = generic_read_dir,
        .readdir        = coda_readdir,
        .open           = coda_open,
        .flush          = coda_flush,
        .release        = coda_release,
        .fsync          = coda_fsync,
};


/* inode operations for directories */
/* access routines: lookup, readlink, permission */
static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, struct nameidata *nd)
{
        struct inode *res_inode = NULL;
        struct CodaFid resfid = { { 0, } };
        int dropme = 0; /* to indicate entry should not be cached */
        int type = 0;
        int error = 0;
        const char *name = entry->d_name.name;
        size_t length = entry->d_name.len;
        
        if ( length > CODA_MAXNAMLEN ) {
                printk("name too long: lookup, %s (%*s)\n", 
                       coda_i2s(dir), (int)length, name);
                return ERR_PTR(-ENAMETOOLONG);
        }

        lock_kernel();
        /* control object, create inode on the fly */
        if (coda_isroot(dir) && coda_iscontrol(name, length)) {
                error = coda_cnode_makectl(&res_inode, dir->i_sb);
                dropme = 1;
                goto exit;
        }

        error = venus_lookup(dir->i_sb, coda_i2f(dir), 
                             (const char *)name, length, &type, &resfid);

        res_inode = NULL;
        if (!error) {
                if (type & CODA_NOCACHE) {
                        type &= (~CODA_NOCACHE);
                        dropme = 1;
                }

                error = coda_cnode_make(&res_inode, &resfid, dir->i_sb);
                if (error) {
                        unlock_kernel();
                        return ERR_PTR(error);
                }
        } else if (error != -ENOENT) {
                unlock_kernel();
                return ERR_PTR(error);
        }

exit:
        entry->d_time = 0;
        entry->d_op = &coda_dentry_operations;
        d_add(entry, res_inode);
        if ( dropme ) {
                d_drop(entry);
                coda_flag_inode(res_inode, C_VATTR);
        }
        unlock_kernel();
        return NULL;
}


int coda_permission(struct inode *inode, int mask, struct nameidata *nd)
{
        int error = 0;
 
        if (!mask)
                return 0; 

        lock_kernel();

        coda_vfs_stat.permission++;

        if (coda_cache_check(inode, mask))
                goto out; 

        error = venus_access(inode->i_sb, coda_i2f(inode), mask);
    
        if (!error)
                coda_cache_enter(inode, mask);

 out:
        unlock_kernel();

        return error; 
}


static inline void coda_dir_changed(struct inode *dir, int link)
{
#ifdef REQUERY_VENUS_FOR_MTIME
        /* invalidate the directory cnode's attributes so we refetch the
         * attributes from venus next time the inode is referenced */
        coda_flag_inode(dir, C_VATTR);
#else
        /* optimistically we can also act as if our nose bleeds. The
         * granularity of the mtime is coarse anyways so we might actually be
         * right most of the time. Note: we only do this for directories. */
        dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
#endif
        if (link)
                dir->i_nlink += link;
}

/* creation routines: create, mknod, mkdir, link, symlink */
static int coda_create(struct inode *dir, struct dentry *de, int mode, struct nameidata *nd)
{
        int error=0;
        const char *name=de->d_name.name;
        int length=de->d_name.len;
        struct inode *inode;
        struct CodaFid newfid;
        struct coda_vattr attrs;

        lock_kernel();
        coda_vfs_stat.create++;

        if (coda_isroot(dir) && coda_iscontrol(name, length)) {
                unlock_kernel();
                return -EPERM;
        }

        error = venus_create(dir->i_sb, coda_i2f(dir), name, length, 
                                0, mode, &newfid, &attrs);

        if ( error ) {
                unlock_kernel();
                d_drop(de);
                return error;
        }

        inode = coda_iget(dir->i_sb, &newfid, &attrs);
        if ( IS_ERR(inode) ) {
                unlock_kernel();
                d_drop(de);
                return PTR_ERR(inode);
        }

        /* invalidate the directory cnode's attributes */
        coda_dir_changed(dir, 0);
        unlock_kernel();
        d_instantiate(de, inode);
        return 0;
}

static int coda_mkdir(struct inode *dir, struct dentry *de, int mode)
{
        struct inode *inode;
        struct coda_vattr attrs;
        const char *name = de->d_name.name;
        int len = de->d_name.len;
        int error;
        struct CodaFid newfid;

        lock_kernel();
        coda_vfs_stat.mkdir++;

        if (coda_isroot(dir) && coda_iscontrol(name, len)) {
                unlock_kernel();
                return -EPERM;
        }

        attrs.va_mode = mode;
        error = venus_mkdir(dir->i_sb, coda_i2f(dir), 
                               name, len, &newfid, &attrs);
        
        if ( error ) {
                unlock_kernel();
                d_drop(de);
                return error;
        }
         
        inode = coda_iget(dir->i_sb, &newfid, &attrs);
        if ( IS_ERR(inode) ) {
                unlock_kernel();
                d_drop(de);
                return PTR_ERR(inode);
        }
        
        /* invalidate the directory cnode's attributes */
        coda_dir_changed(dir, 1);
        unlock_kernel();
        d_instantiate(de, inode);
        return 0;
}

/* try to make de an entry in dir_inodde linked to source_de */ 
static int coda_link(struct dentry *source_de, struct inode *dir_inode, 
          struct dentry *de)
{
        struct inode *inode = source_de->d_inode;
        const char * name = de->d_name.name;
        int len = de->d_name.len;
        int error;

        lock_kernel();
        coda_vfs_stat.link++;

        if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
                unlock_kernel();
                return -EPERM;
        }

        error = venus_link(dir_inode->i_sb, coda_i2f(inode),
                           coda_i2f(dir_inode), (const char *)name, len);

        if (error) { 
                d_drop(de);
                goto out;
        }

        coda_dir_changed(dir_inode, 0);
        atomic_inc(&inode->i_count);
        d_instantiate(de, inode);
        inode->i_nlink++;
        
out:
        unlock_kernel();
        return(error);
}


static int coda_symlink(struct inode *dir_inode, struct dentry *de,
                        const char *symname)
{
        const char *name = de->d_name.name;
        int len = de->d_name.len;
        int symlen;
        int error=0;
        
        lock_kernel();
        coda_vfs_stat.symlink++;

        if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
                unlock_kernel();
                return -EPERM;
        }

        symlen = strlen(symname);
        if ( symlen > CODA_MAXPATHLEN ) {
                unlock_kernel();
                return -ENAMETOOLONG;
        }

        /*
         * This entry is now negative. Since we do not create
         * an inode for the entry we have to drop it. 
         */
        d_drop(de);
        error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len, 
                              symname, symlen);

        /* mtime is no good anymore */
        if ( !error )
                coda_dir_changed(dir_inode, 0);

        unlock_kernel();
        return error;
}

/* destruction routines: unlink, rmdir */
int coda_unlink(struct inode *dir, struct dentry *de)
{
        int error;
        const char *name = de->d_name.name;
        int len = de->d_name.len;

        lock_kernel();
        coda_vfs_stat.unlink++;

        error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
        if ( error ) {
                unlock_kernel();
                return error;
        }

        coda_dir_changed(dir, 0);
        de->d_inode->i_nlink--;
        unlock_kernel();

        return 0;
}

int coda_rmdir(struct inode *dir, struct dentry *de)
{
        const char *name = de->d_name.name;
        int len = de->d_name.len;
        int error;

        lock_kernel();
        coda_vfs_stat.rmdir++;

        if (!d_unhashed(de)) {
                unlock_kernel();
                return -EBUSY;
        }
        error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);

        if ( error ) {
                unlock_kernel();
                return error;
        }

        coda_dir_changed(dir, -1);
        de->d_inode->i_nlink--;
        d_delete(de);
        unlock_kernel();

        return 0;
}

/* rename */
static int coda_rename(struct inode *old_dir, struct dentry *old_dentry, 
                       struct inode *new_dir, struct dentry *new_dentry)
{
        const char *old_name = old_dentry->d_name.name;
        const char *new_name = new_dentry->d_name.name;
        int old_length = old_dentry->d_name.len;
        int new_length = new_dentry->d_name.len;
        int link_adjust = 0;
        int error;

        lock_kernel();
        coda_vfs_stat.rename++;

        error = venus_rename(old_dir->i_sb, coda_i2f(old_dir), 
                             coda_i2f(new_dir), old_length, new_length, 
                             (const char *) old_name, (const char *)new_name);

        if ( !error ) {
                if ( new_dentry->d_inode ) {
                        if ( S_ISDIR(new_dentry->d_inode->i_mode) )
                                link_adjust = 1;

                        coda_dir_changed(old_dir, -link_adjust);
                        coda_dir_changed(new_dir,  link_adjust);
                        coda_flag_inode(new_dentry->d_inode, C_VATTR);
                } else {
                        coda_flag_inode(old_dir, C_VATTR);
                        coda_flag_inode(new_dir, C_VATTR);
                }
        }
        unlock_kernel();

        return error;
}


/* file operations for directories */
int coda_readdir(struct file *coda_file, void *dirent, filldir_t filldir)
{
        struct dentry *coda_dentry = coda_file->f_dentry;
        struct coda_file_info *cfi;
        struct file *host_file;
        struct inode *host_inode;
        int ret;

        cfi = CODA_FTOC(coda_file);
        BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
        host_file = cfi->cfi_container;

        coda_vfs_stat.readdir++;

        host_inode = host_file->f_dentry->d_inode;
        down(&host_inode->i_sem);
        host_file->f_pos = coda_file->f_pos;

        if (!host_file->f_op->readdir) {
                /* Venus: we must read Venus dirents from the file */
                ret = coda_venus_readdir(host_file, filldir, dirent, coda_dentry);
        } else {
                /* potemkin case: we were handed a directory inode. */
                /* Yuk, we can't call vfs_readdir because we are already
                 * holding the inode semaphore. */
                ret = -ENOTDIR;
                if (!host_file->f_op || !host_file->f_op->readdir)
                        goto out;

                ret = -ENOENT;
                if (!IS_DEADDIR(host_inode)) {
                        ret = host_file->f_op->readdir(host_file, filldir, dirent);
                        file_accessed(host_file);
                }
        }
out:
        coda_file->f_pos = host_file->f_pos;
        up(&host_inode->i_sem);

        return ret;
}

static inline unsigned int CDT2DT(unsigned char cdt)
{
        unsigned int dt;

        switch(cdt) {
        case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
        case CDT_FIFO:    dt = DT_FIFO;    break;
        case CDT_CHR:     dt = DT_CHR;     break;
        case CDT_DIR:     dt = DT_DIR;     break;
        case CDT_BLK:     dt = DT_BLK;     break;
        case CDT_REG:     dt = DT_REG;     break;
        case CDT_LNK:     dt = DT_LNK;     break;
        case CDT_SOCK:    dt = DT_SOCK;    break;
        case CDT_WHT:     dt = DT_WHT;     break;
        default:          dt = DT_UNKNOWN; break;
        }
        return dt;
}

/* support routines */
static int coda_venus_readdir(struct file *filp, filldir_t filldir,
                              void *dirent, struct dentry *dir)
{
        int result = 0; /* # of entries returned */
        struct venus_dirent *vdir;
        unsigned long vdir_size =
            (unsigned long)(&((struct venus_dirent *)0)->d_name);
        unsigned int type;
        struct qstr name;
        ino_t ino;
        int ret, i;

        vdir = (struct venus_dirent *)kmalloc(sizeof(*vdir), GFP_KERNEL);
        if (!vdir) return -ENOMEM;

        i = filp->f_pos;
        switch(i) {
        case 0:
                ret = filldir(dirent, ".", 1, 0, dir->d_inode->i_ino, DT_DIR);
                if (ret < 0) break;
                result++;
                filp->f_pos++;
                /* fallthrough */
        case 1:
                ret = filldir(dirent, "..", 2, 1, dir->d_parent->d_inode->i_ino, DT_DIR);
                if (ret < 0) break;
                result++;
                filp->f_pos++;
                /* fallthrough */
        default:
        while (1) {
                /* read entries from the directory file */
                ret = kernel_read(filp, filp->f_pos - 2, (char *)vdir,
                                  sizeof(*vdir));
                if (ret < 0) {
                        printk("coda_venus_readdir: read dir failed %d\n", ret);
                        break;
                }
                if (ret == 0) break; /* end of directory file reached */

                /* catch truncated reads */
                if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
                        printk("coda_venus_readdir: short read: %ld\n",
                               filp->f_dentry->d_inode->i_ino);
                        ret = -EBADF;
                        break;
                }
                /* validate whether the directory file actually makes sense */
                if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
                        printk("coda_venus_readdir: Invalid dir: %ld\n",
                               filp->f_dentry->d_inode->i_ino);
                        ret = -EBADF;
                        break;
                }

                name.len = vdir->d_namlen;
                name.name = vdir->d_name;

                /* Make sure we skip '.' and '..', we already got those */
                if (name.name[0] == '.' && (name.len == 1 ||
                    (vdir->d_name[1] == '.' && name.len == 2)))
                        vdir->d_fileno = name.len = 0;

                /* skip null entries */
                if (vdir->d_fileno && name.len) {
                        /* try to look up this entry in the dcache, that way
                         * userspace doesn't have to worry about breaking
                         * getcwd by having mismatched inode numbers for
                         * internal volume mountpoints. */
                        ino = find_inode_number(dir, &name);
                        if (!ino) ino = vdir->d_fileno;

                        type = CDT2DT(vdir->d_type);
                        ret = filldir(dirent, name.name, name.len, filp->f_pos,
                                      ino, type); 
                        /* failure means no space for filling in this round */
                        if (ret < 0) break;
                        result++;
                }
                /* we'll always have progress because d_reclen is unsigned and
                 * we've already established it is non-zero. */
                filp->f_pos += vdir->d_reclen;
        }
        } 
        kfree(vdir);
        return result ? result : ret;
}

/* called when a cache lookup succeeds */
static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd)
{
        struct inode *inode = de->d_inode;
        struct coda_inode_info *cii;

        if (!inode)
                return 1;
        lock_kernel();
        if (coda_isroot(inode))
                goto out;
        if (is_bad_inode(inode))
                goto bad;

        cii = ITOC(de->d_inode);
        if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
                goto out;

        shrink_dcache_parent(de);

        /* propagate for a flush */
        if (cii->c_flags & C_FLUSH) 
                coda_flag_inode_children(inode, C_FLUSH);

        if (atomic_read(&de->d_count) > 1)
                /* pretend it's valid, but don't change the flags */
                goto out;

        /* clear the flags. */
        cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);

bad:
        unlock_kernel();
        return 0;
out:
        unlock_kernel();
        return 1;
}

/*
 * This is the callback from dput() when d_count is going to 0.
 * We use this to unhash dentries with bad inodes.
 */
static int coda_dentry_delete(struct dentry * dentry)
{
        int flags;

        if (!dentry->d_inode) 
                return 0;

        flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
        if (is_bad_inode(dentry->d_inode) || flags) {
                return 1;
        }
        return 0;
}



/*
 * This is called when we want to check if the inode has
 * changed on the server.  Coda makes this easy since the
 * cache manager Venus issues a downcall to the kernel when this 
 * happens 
 */
int coda_revalidate_inode(struct dentry *dentry)
{
        struct coda_vattr attr;
        int error = 0;
        int old_mode;
        ino_t old_ino;
        struct inode *inode = dentry->d_inode;
        struct coda_inode_info *cii = ITOC(inode);

        lock_kernel();
        if ( !cii->c_flags )
                goto ok;

        if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
                error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
                if ( error )
                        goto return_bad;

                /* this inode may be lost if:
                   - it's ino changed 
                   - type changes must be permitted for repair and
                   missing mount points.
                */
                old_mode = inode->i_mode;
                old_ino = inode->i_ino;
                coda_vattr_to_iattr(inode, &attr);

                if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
                        printk("Coda: inode %ld, fid %s changed type!\n",
                               inode->i_ino, coda_f2s(&(cii->c_fid)));
                }

                /* the following can happen when a local fid is replaced 
                   with a global one, here we lose and declare the inode bad */
                if (inode->i_ino != old_ino)
                        goto return_bad;
                
                coda_flag_inode_children(inode, C_FLUSH);
                cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
        }

ok:
        unlock_kernel();
        return 0;

return_bad:
        unlock_kernel();
        return -EIO;
}