inode.c

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/*
 * Copyright (c) 2002 Red Hat, Inc. All rights reserved.
 *
 * This software may be freely redistributed under the terms of the
 * GNU General Public License.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Authors: David Woodhouse <[email protected]>
 *          David Howells <[email protected]>
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/sched.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include "internal.h"

struct afs_iget_data {
    struct afs_fid      fid;
    struct afs_volume   *volume;    /* volume on which resides */
};

/*
 * map the AFS file status to the inode member variables
 */
static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
{
    struct inode *inode = AFS_VNODE_TO_I(vnode);

    _debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
           vnode->status.type,
           vnode->status.nlink,
           (unsigned long long) vnode->status.size,
           vnode->status.data_version,
           vnode->status.mode);

    switch (vnode->status.type) {
    case AFS_FTYPE_FILE:
        inode->i_mode   = S_IFREG | vnode->status.mode;
        inode->i_op = &afs_file_inode_operations;
        inode->i_fop    = &afs_file_operations;
        break;
    case AFS_FTYPE_DIR:
        inode->i_mode   = S_IFDIR | vnode->status.mode;
        inode->i_op = &afs_dir_inode_operations;
        inode->i_fop    = &afs_dir_file_operations;
        break;
    case AFS_FTYPE_SYMLINK:
        inode->i_mode   = S_IFLNK | vnode->status.mode;
        inode->i_op = &page_symlink_inode_operations;
        break;
    default:
        printk("kAFS: AFS vnode with undefined type\n");
        return -EBADMSG;
    }

#ifdef CONFIG_AFS_FSCACHE
    if (vnode->status.size != inode->i_size)
        fscache_attr_changed(vnode->cache);
#endif

    set_nlink(inode, vnode->status.nlink);
    inode->i_uid        = vnode->status.owner;
    inode->i_gid        = 0;
    inode->i_size       = vnode->status.size;
    inode->i_ctime.tv_sec   = vnode->status.mtime_server;
    inode->i_ctime.tv_nsec  = 0;
    inode->i_atime      = inode->i_mtime = inode->i_ctime;
    inode->i_blocks     = 0;
    inode->i_generation = vnode->fid.unique;
    inode->i_version    = vnode->status.data_version;
    inode->i_mapping->a_ops = &afs_fs_aops;

    /* check to see whether a symbolic link is really a mountpoint */
    if (vnode->status.type == AFS_FTYPE_SYMLINK) {
        afs_mntpt_check_symlink(vnode, key);

        if (test_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags)) {
            inode->i_mode   = S_IFDIR | vnode->status.mode;
            inode->i_op = &afs_mntpt_inode_operations;
            inode->i_fop    = &afs_mntpt_file_operations;
        }
    }

    return 0;
}

/*
 * iget5() comparator
 */
static int afs_iget5_test(struct inode *inode, void *opaque)
{
    struct afs_iget_data *data = opaque;

    return inode->i_ino == data->fid.vnode &&
        inode->i_generation == data->fid.unique;
}

/*
 * iget5() comparator for inode created by autocell operations
 *
 * These pseudo inodes don't match anything.
 */
static int afs_iget5_autocell_test(struct inode *inode, void *opaque)
{
    return 0;
}

/*
 * iget5() inode initialiser
 */
static int afs_iget5_set(struct inode *inode, void *opaque)
{
    struct afs_iget_data *data = opaque;
    struct afs_vnode *vnode = AFS_FS_I(inode);

    inode->i_ino = data->fid.vnode;
    inode->i_generation = data->fid.unique;
    vnode->fid = data->fid;
    vnode->volume = data->volume;

    return 0;
}

/*
 * inode retrieval for autocell
 */
struct inode *afs_iget_autocell(struct inode *dir, const char *dev_name,
                int namesz, struct key *key)
{
    struct afs_iget_data data;
    struct afs_super_info *as;
    struct afs_vnode *vnode;
    struct super_block *sb;
    struct inode *inode;
    static atomic_t afs_autocell_ino;

    _enter("{%x:%u},%*.*s,",
           AFS_FS_I(dir)->fid.vid, AFS_FS_I(dir)->fid.vnode,
           namesz, namesz, dev_name ?: "");

    sb = dir->i_sb;
    as = sb->s_fs_info;
    data.volume = as->volume;
    data.fid.vid = as->volume->vid;
    data.fid.unique = 0;
    data.fid.vnode = 0;

    inode = iget5_locked(sb, atomic_inc_return(&afs_autocell_ino),
                 afs_iget5_autocell_test, afs_iget5_set,
                 &data);
    if (!inode) {
        _leave(" = -ENOMEM");
        return ERR_PTR(-ENOMEM);
    }

    _debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }",
           inode, inode->i_ino, data.fid.vid, data.fid.vnode,
           data.fid.unique);

    vnode = AFS_FS_I(inode);

    /* there shouldn't be an existing inode */
    BUG_ON(!(inode->i_state & I_NEW));

    inode->i_size       = 0;
    inode->i_mode       = S_IFDIR | S_IRUGO | S_IXUGO;
    inode->i_op     = &afs_autocell_inode_operations;
    set_nlink(inode, 2);
    inode->i_uid        = 0;
    inode->i_gid        = 0;
    inode->i_ctime.tv_sec   = get_seconds();
    inode->i_ctime.tv_nsec  = 0;
    inode->i_atime      = inode->i_mtime = inode->i_ctime;
    inode->i_blocks     = 0;
    inode->i_version    = 0;
    inode->i_generation = 0;

    set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
    set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
    inode->i_flags |= S_AUTOMOUNT | S_NOATIME;
    unlock_new_inode(inode);
    _leave(" = %p", inode);
    return inode;
}

/*
 * inode retrieval
 */
struct inode *afs_iget(struct super_block *sb, struct key *key,
               struct afs_fid *fid, struct afs_file_status *status,
               struct afs_callback *cb)
{
    struct afs_iget_data data = { .fid = *fid };
    struct afs_super_info *as;
    struct afs_vnode *vnode;
    struct inode *inode;
    int ret;

    _enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);

    as = sb->s_fs_info;
    data.volume = as->volume;

    inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
                 &data);
    if (!inode) {
        _leave(" = -ENOMEM");
        return ERR_PTR(-ENOMEM);
    }

    _debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
           inode, fid->vid, fid->vnode, fid->unique);

    vnode = AFS_FS_I(inode);

    /* deal with an existing inode */
    if (!(inode->i_state & I_NEW)) {
        _leave(" = %p", inode);
        return inode;
    }

    if (!status) {
        /* it's a remotely extant inode */
        set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
        ret = afs_vnode_fetch_status(vnode, NULL, key);
        if (ret < 0)
            goto bad_inode;
    } else {
        /* it's an inode we just created */
        memcpy(&vnode->status, status, sizeof(vnode->status));

        if (!cb) {
            /* it's a symlink we just created (the fileserver
             * didn't give us a callback) */
            vnode->cb_version = 0;
            vnode->cb_expiry = 0;
            vnode->cb_type = 0;
            vnode->cb_expires = get_seconds();
        } else {
            vnode->cb_version = cb->version;
            vnode->cb_expiry = cb->expiry;
            vnode->cb_type = cb->type;
            vnode->cb_expires = vnode->cb_expiry + get_seconds();
        }
    }

    /* set up caching before mapping the status, as map-status reads the
     * first page of symlinks to see if they're really mountpoints */
    inode->i_size = vnode->status.size;
#ifdef CONFIG_AFS_FSCACHE
    vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
                          &afs_vnode_cache_index_def,
                          vnode);
#endif

    ret = afs_inode_map_status(vnode, key);
    if (ret < 0)
        goto bad_inode;

    /* success */
    clear_bit(AFS_VNODE_UNSET, &vnode->flags);
    inode->i_flags |= S_NOATIME;
    unlock_new_inode(inode);
    _leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
    return inode;

    /* failure */
bad_inode:
#ifdef CONFIG_AFS_FSCACHE
    fscache_relinquish_cookie(vnode->cache, 0);
    vnode->cache = NULL;
#endif
    iget_failed(inode);
    _leave(" = %d [bad]", ret);
    return ERR_PTR(ret);
}

/*
 * mark the data attached to an inode as obsolete due to a write on the server
 * - might also want to ditch all the outstanding writes and dirty pages
 */
void afs_zap_data(struct afs_vnode *vnode)
{
    _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);

    /* nuke all the non-dirty pages that aren't locked, mapped or being
     * written back in a regular file and completely discard the pages in a
     * directory or symlink */
    if (S_ISREG(vnode->vfs_inode.i_mode))
        invalidate_remote_inode(&vnode->vfs_inode);
    else
        invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
}

/*
 * validate a vnode/inode
 * - there are several things we need to check
 *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
 *     symlink)
 *   - parent dir metadata changed (security changes)
 *   - dentry data changed (write, truncate)
 *   - dentry metadata changed (security changes)
 */
int afs_validate(struct afs_vnode *vnode, struct key *key)
{
    int ret;

    _enter("{v={%x:%u} fl=%lx},%x",
           vnode->fid.vid, vnode->fid.vnode, vnode->flags,
           key_serial(key));

    if (vnode->cb_promised &&
        !test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
        !test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
        !test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
        if (vnode->cb_expires < get_seconds() + 10) {
            _debug("callback expired");
            set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
        } else {
            goto valid;
        }
    }

    if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
        goto valid;

    mutex_lock(&vnode->validate_lock);

    /* if the promise has expired, we need to check the server again to get
     * a new promise - note that if the (parent) directory's metadata was
     * changed then the security may be different and we may no longer have
     * access */
    if (!vnode->cb_promised ||
        test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
        _debug("not promised");
        ret = afs_vnode_fetch_status(vnode, NULL, key);
        if (ret < 0)
            goto error_unlock;
        _debug("new promise [fl=%lx]", vnode->flags);
    }

    if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
        _debug("file already deleted");
        ret = -ESTALE;
        goto error_unlock;
    }

    /* if the vnode's data version number changed then its contents are
     * different */
    if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
        afs_zap_data(vnode);

    clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
    mutex_unlock(&vnode->validate_lock);
valid:
    _leave(" = 0");
    return 0;

error_unlock:
    mutex_unlock(&vnode->validate_lock);
    _leave(" = %d", ret);
    return ret;
}

/*
 * read the attributes of an inode
 */
int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
              struct kstat *stat)
{
    struct inode *inode;

    inode = dentry->d_inode;

    _enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);

    generic_fillattr(inode, stat);
    return 0;
}

/*
 * discard an AFS inode
 */
int afs_drop_inode(struct inode *inode)
{
    _enter("");

    if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
        return generic_delete_inode(inode);
    else
        return generic_drop_inode(inode);
}

/*
 * clear an AFS inode
 */
void afs_evict_inode(struct inode *inode)
{
    struct afs_permits *permits;
    struct afs_vnode *vnode;

    vnode = AFS_FS_I(inode);

    _enter("{%x:%u.%d} v=%u x=%u t=%u }",
           vnode->fid.vid,
           vnode->fid.vnode,
           vnode->fid.unique,
           vnode->cb_version,
           vnode->cb_expiry,
           vnode->cb_type);

    _debug("CLEAR INODE %p", inode);

    ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);

    truncate_inode_pages(&inode->i_data, 0);
    clear_inode(inode);

    afs_give_up_callback(vnode);

    if (vnode->server) {
        spin_lock(&vnode->server->fs_lock);
        rb_erase(&vnode->server_rb, &vnode->server->fs_vnodes);
        spin_unlock(&vnode->server->fs_lock);
        afs_put_server(vnode->server);
        vnode->server = NULL;
    }

    ASSERT(list_empty(&vnode->writebacks));
    ASSERT(!vnode->cb_promised);

#ifdef CONFIG_AFS_FSCACHE
    fscache_relinquish_cookie(vnode->cache, 0);
    vnode->cache = NULL;
#endif

    mutex_lock(&vnode->permits_lock);
    permits = vnode->permits;
    rcu_assign_pointer(vnode->permits, NULL);
    mutex_unlock(&vnode->permits_lock);
    if (permits)
        call_rcu(&permits->rcu, afs_zap_permits);

    _leave("");
}

/*
 * set the attributes of an inode
 */
int afs_setattr(struct dentry *dentry, struct iattr *attr)
{
    struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
    struct key *key;
    int ret;

    _enter("{%x:%u},{n=%s},%x",
           vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
           attr->ia_valid);

    if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
                ATTR_MTIME))) {
        _leave(" = 0 [unsupported]");
        return 0;
    }

    /* flush any dirty data outstanding on a regular file */
    if (S_ISREG(vnode->vfs_inode.i_mode)) {
        filemap_write_and_wait(vnode->vfs_inode.i_mapping);
        afs_writeback_all(vnode);
    }

    if (attr->ia_valid & ATTR_FILE) {
        key = attr->ia_file->private_data;
    } else {
        key = afs_request_key(vnode->volume->cell);
        if (IS_ERR(key)) {
            ret = PTR_ERR(key);
            goto error;
        }
    }

    ret = afs_vnode_setattr(vnode, key, attr);
    if (!(attr->ia_valid & ATTR_FILE))
        key_put(key);

error:
    _leave(" = %d", ret);
    return ret;
}