fs/smbsrv/smb_vfs.c

	smb_vfs.c revision faa1795a28a5c712eed6d0a3f84d98c368a316c6
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <smbsrv/smb_incl.h>
#include <smbsrv/smb_fsops.h>
#include <sys/vfs.h>

static smb_vfs_t *smb_vfs_lookup(smb_server_t *, vnode_t *);

/*
 * smb_vfs_hold
 *
 * Increments the reference count of the fs passed in. If no smb_vfs_t structure
 * has been created yet for the fs passed in it is created.
 */
boolean_t
smb_vfs_hold(smb_server_t *sv, vfs_t *vfsp)
{
    smb_vfs_t   *smb_vfs;
    vnode_t     *rootvp;

    if ((vfsp == NULL) || VFS_ROOT(vfsp, &rootvp))
        return (B_FALSE);

    smb_llist_enter(&sv->sv_vfs_list, RW_WRITER);
    smb_vfs = smb_vfs_lookup(sv, rootvp);
    if (smb_vfs) {
        DTRACE_PROBE1(smb_vfs_hold_hit, smb_vfs_t *, smb_vfs);
        smb_llist_exit(&sv->sv_vfs_list);
        VN_RELE(rootvp);
        return (B_TRUE);
    }
    smb_vfs = kmem_cache_alloc(sv->si_cache_vfs, KM_SLEEP);

    bzero(smb_vfs, sizeof (smb_vfs_t));

    smb_vfs->sv_magic = SMB_VFS_MAGIC;
    smb_vfs->sv_refcnt = 1;
    smb_vfs->sv_vfsp = vfsp;
    /*
     * We have a hold on the root vnode of the file system
     * from the VFS_ROOT call above.
     */
    smb_vfs->sv_rootvp = rootvp;
    smb_llist_insert_head(&sv->sv_vfs_list, smb_vfs);
    DTRACE_PROBE1(smb_vfs_hold_miss, smb_vfs_t *, smb_vfs);
    smb_llist_exit(&sv->sv_vfs_list);
    return (B_TRUE);
}

/*
 * smb_vfs_rele
 *
 * Decrements the reference count of the fs passed in. If the reference count
 * drops to zero the smb_vfs_t structure associated with the fs is freed.
 */
void
smb_vfs_rele(smb_server_t *sv, vfs_t *vfsp)
{
    smb_vfs_t   *smb_vfs;
    vnode_t     *rootvp;

    ASSERT(vfsp);

    if (VFS_ROOT(vfsp, &rootvp))
        return;

    smb_llist_enter(&sv->sv_vfs_list, RW_WRITER);
    smb_vfs = smb_vfs_lookup(sv, rootvp);
    DTRACE_PROBE2(smb_vfs_release, smb_vfs_t *, smb_vfs, vnode_t *, rootvp);
    VN_RELE(rootvp);
    if (smb_vfs) {
        --smb_vfs->sv_refcnt;
        ASSERT(smb_vfs->sv_refcnt);
        if (--smb_vfs->sv_refcnt == 0) {
            smb_llist_remove(&sv->sv_vfs_list, smb_vfs);
            smb_llist_exit(&sv->sv_vfs_list);
            ASSERT(rootvp == smb_vfs->sv_rootvp);
            VN_RELE(smb_vfs->sv_rootvp);
            smb_vfs->sv_magic = (uint32_t)~SMB_VFS_MAGIC;
            kmem_cache_free(sv->si_cache_vfs, smb_vfs);
            return;
        }
    }
    smb_llist_exit(&sv->sv_vfs_list);
}

/*
 * smb_vfs_rele_all()
 *
 * Release all holds on root vnodes of file systems which were taken
 * due to the existence of at least one enabled share on the file system.
 * Called at driver close time.
 */
void
smb_vfs_rele_all(smb_server_t *sv)
{
    smb_vfs_t   *smb_vfs;

    smb_llist_enter(&sv->sv_vfs_list, RW_WRITER);
    while ((smb_vfs = smb_llist_head(&sv->sv_vfs_list)) != NULL) {

        ASSERT(smb_vfs->sv_magic == SMB_VFS_MAGIC);
        DTRACE_PROBE1(smb_vfs_rele_all_hit, smb_vfs_t *, smb_vfs);
        smb_llist_remove(&sv->sv_vfs_list, smb_vfs);
        VN_RELE(smb_vfs->sv_rootvp);
        kmem_cache_free(sv->si_cache_vfs, smb_vfs);
    }
    smb_llist_exit(&sv->sv_vfs_list);
}

/*
 * smb_vfs_lookup
 *
 * Goes through the list of smb_vfs_t structure and returns the one matching
 * the vnode passed in. If no match is found a NULL pointer is returned.
 *
 * The list of smb_vfs_t structures has to have been entered prior calling
 * this function.
 */
static smb_vfs_t *
smb_vfs_lookup(smb_server_t *sv, vnode_t *rootvp)
{
    smb_vfs_t   *smb_vfs;

    smb_vfs = smb_llist_head(&sv->sv_vfs_list);
    while (smb_vfs) {
        ASSERT(smb_vfs->sv_magic == SMB_VFS_MAGIC);
        if (smb_vfs->sv_rootvp == rootvp) {
            smb_vfs->sv_refcnt++;
            ASSERT(smb_vfs->sv_refcnt);
            return (smb_vfs);
        }
        smb_vfs = smb_llist_next(&sv->sv_vfs_list, smb_vfs);
    }
    return (NULL);
}