UIO: hold a reference to the device's owner while the device is open

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / xfs / xfs_vfsops.c

/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_btree.h"
#include "xfs_alloc.h"
#include "xfs_ialloc.h"
#include "xfs_quota.h"
#include "xfs_error.h"
#include "xfs_bmap.h"
#include "xfs_rw.h"
#include "xfs_buf_item.h"
#include "xfs_log_priv.h"
#include "xfs_dir2_trace.h"
#include "xfs_extfree_item.h"
#include "xfs_acl.h"
#include "xfs_attr.h"
#include "xfs_clnt.h"
#include "xfs_mru_cache.h"
#include "xfs_filestream.h"
#include "xfs_fsops.h"
#include "xfs_vnodeops.h"
#include "xfs_vfsops.h"
#include "xfs_utils.h"


int __init
xfs_init(void)
{
#ifdef XFS_DABUF_DEBUG
        extern spinlock_t        xfs_dabuf_global_lock;
        spin_lock_init(&xfs_dabuf_global_lock);
#endif

        /*
         * Initialize all of the zone allocators we use.
         */
        xfs_log_ticket_zone = kmem_zone_init(sizeof(xlog_ticket_t),
                                                "xfs_log_ticket");
        xfs_bmap_free_item_zone = kmem_zone_init(sizeof(xfs_bmap_free_item_t),
                                                "xfs_bmap_free_item");
        xfs_btree_cur_zone = kmem_zone_init(sizeof(xfs_btree_cur_t),
                                                "xfs_btree_cur");
        xfs_da_state_zone = kmem_zone_init(sizeof(xfs_da_state_t),
                                                "xfs_da_state");
        xfs_dabuf_zone = kmem_zone_init(sizeof(xfs_dabuf_t), "xfs_dabuf");
        xfs_ifork_zone = kmem_zone_init(sizeof(xfs_ifork_t), "xfs_ifork");
        xfs_trans_zone = kmem_zone_init(sizeof(xfs_trans_t), "xfs_trans");
        xfs_acl_zone_init(xfs_acl_zone, "xfs_acl");
        xfs_mru_cache_init();
        xfs_filestream_init();

        /*
         * The size of the zone allocated buf log item is the maximum
         * size possible under XFS.  This wastes a little bit of memory,
         * but it is much faster.
         */
        xfs_buf_item_zone =
                kmem_zone_init((sizeof(xfs_buf_log_item_t) +
                                (((XFS_MAX_BLOCKSIZE / XFS_BLI_CHUNK) /
                                  NBWORD) * sizeof(int))),
                               "xfs_buf_item");
        xfs_efd_zone =
                kmem_zone_init((sizeof(xfs_efd_log_item_t) +
                               ((XFS_EFD_MAX_FAST_EXTENTS - 1) *
                                 sizeof(xfs_extent_t))),
                                      "xfs_efd_item");
        xfs_efi_zone =
                kmem_zone_init((sizeof(xfs_efi_log_item_t) +
                               ((XFS_EFI_MAX_FAST_EXTENTS - 1) *
                                 sizeof(xfs_extent_t))),
                                      "xfs_efi_item");

        /*
         * These zones warrant special memory allocator hints
         */
        xfs_inode_zone =
                kmem_zone_init_flags(sizeof(xfs_inode_t), "xfs_inode",
                                        KM_ZONE_HWALIGN | KM_ZONE_RECLAIM |
                                        KM_ZONE_SPREAD, NULL);
        xfs_ili_zone =
                kmem_zone_init_flags(sizeof(xfs_inode_log_item_t), "xfs_ili",
                                        KM_ZONE_SPREAD, NULL);

        /*
         * Allocate global trace buffers.
         */
#ifdef XFS_ALLOC_TRACE
        xfs_alloc_trace_buf = ktrace_alloc(XFS_ALLOC_TRACE_SIZE, KM_SLEEP);
#endif
#ifdef XFS_BMAP_TRACE
        xfs_bmap_trace_buf = ktrace_alloc(XFS_BMAP_TRACE_SIZE, KM_SLEEP);
#endif
#ifdef XFS_BMBT_TRACE
        xfs_bmbt_trace_buf = ktrace_alloc(XFS_BMBT_TRACE_SIZE, KM_SLEEP);
#endif
#ifdef XFS_ATTR_TRACE
        xfs_attr_trace_buf = ktrace_alloc(XFS_ATTR_TRACE_SIZE, KM_SLEEP);
#endif
#ifdef XFS_DIR2_TRACE
        xfs_dir2_trace_buf = ktrace_alloc(XFS_DIR2_GTRACE_SIZE, KM_SLEEP);
#endif

        xfs_dir_startup();

#if (defined(DEBUG) || defined(INDUCE_IO_ERROR))
        xfs_error_test_init();
#endif /* DEBUG || INDUCE_IO_ERROR */

        xfs_init_procfs();
        xfs_sysctl_register();
        return 0;
}

void __exit
xfs_cleanup(void)
{
        extern kmem_zone_t      *xfs_inode_zone;
        extern kmem_zone_t      *xfs_efd_zone;
        extern kmem_zone_t      *xfs_efi_zone;

        xfs_cleanup_procfs();
        xfs_sysctl_unregister();
        xfs_filestream_uninit();
        xfs_mru_cache_uninit();
        xfs_acl_zone_destroy(xfs_acl_zone);

#ifdef XFS_DIR2_TRACE
        ktrace_free(xfs_dir2_trace_buf);
#endif
#ifdef XFS_ATTR_TRACE
        ktrace_free(xfs_attr_trace_buf);
#endif
#ifdef XFS_BMBT_TRACE
        ktrace_free(xfs_bmbt_trace_buf);
#endif
#ifdef XFS_BMAP_TRACE
        ktrace_free(xfs_bmap_trace_buf);
#endif
#ifdef XFS_ALLOC_TRACE
        ktrace_free(xfs_alloc_trace_buf);
#endif

        kmem_zone_destroy(xfs_bmap_free_item_zone);
        kmem_zone_destroy(xfs_btree_cur_zone);
        kmem_zone_destroy(xfs_inode_zone);
        kmem_zone_destroy(xfs_trans_zone);
        kmem_zone_destroy(xfs_da_state_zone);
        kmem_zone_destroy(xfs_dabuf_zone);
        kmem_zone_destroy(xfs_buf_item_zone);
        kmem_zone_destroy(xfs_efd_zone);
        kmem_zone_destroy(xfs_efi_zone);
        kmem_zone_destroy(xfs_ifork_zone);
        kmem_zone_destroy(xfs_ili_zone);
}

/*
 * xfs_start_flags
 *
 * This function fills in xfs_mount_t fields based on mount args.
 * Note: the superblock has _not_ yet been read in.
 */
STATIC int
xfs_start_flags(
        struct xfs_mount_args   *ap,
        struct xfs_mount        *mp)
{
        /* Values are in BBs */
        if ((ap->flags & XFSMNT_NOALIGN) != XFSMNT_NOALIGN) {
                /*
                 * At this point the superblock has not been read
                 * in, therefore we do not know the block size.
                 * Before the mount call ends we will convert
                 * these to FSBs.
                 */
                mp->m_dalign = ap->sunit;
                mp->m_swidth = ap->swidth;
        }

        if (ap->logbufs != -1 &&
            ap->logbufs != 0 &&
            (ap->logbufs < XLOG_MIN_ICLOGS ||
             ap->logbufs > XLOG_MAX_ICLOGS)) {
                cmn_err(CE_WARN,
                        "XFS: invalid logbufs value: %d [not %d-%d]",
                        ap->logbufs, XLOG_MIN_ICLOGS, XLOG_MAX_ICLOGS);
                return XFS_ERROR(EINVAL);
        }
        mp->m_logbufs = ap->logbufs;
        if (ap->logbufsize != -1 &&
            ap->logbufsize !=  0 &&
            (ap->logbufsize < XLOG_MIN_RECORD_BSIZE ||
             ap->logbufsize > XLOG_MAX_RECORD_BSIZE ||
             !is_power_of_2(ap->logbufsize))) {
                cmn_err(CE_WARN,
        "XFS: invalid logbufsize: %d [not 16k,32k,64k,128k or 256k]",
                        ap->logbufsize);
                return XFS_ERROR(EINVAL);
        }
        mp->m_logbsize = ap->logbufsize;
        mp->m_fsname_len = strlen(ap->fsname) + 1;
        mp->m_fsname = kmem_alloc(mp->m_fsname_len, KM_SLEEP);
        strcpy(mp->m_fsname, ap->fsname);
        if (ap->rtname[0]) {
                mp->m_rtname = kmem_alloc(strlen(ap->rtname) + 1, KM_SLEEP);
                strcpy(mp->m_rtname, ap->rtname);
        }
        if (ap->logname[0]) {
                mp->m_logname = kmem_alloc(strlen(ap->logname) + 1, KM_SLEEP);
                strcpy(mp->m_logname, ap->logname);
        }

        if (ap->flags & XFSMNT_WSYNC)
                mp->m_flags |= XFS_MOUNT_WSYNC;
#if XFS_BIG_INUMS
        if (ap->flags & XFSMNT_INO64) {
                mp->m_flags |= XFS_MOUNT_INO64;
                mp->m_inoadd = XFS_INO64_OFFSET;
        }
#endif
        if (ap->flags & XFSMNT_RETERR)
                mp->m_flags |= XFS_MOUNT_RETERR;
        if (ap->flags & XFSMNT_NOALIGN)
                mp->m_flags |= XFS_MOUNT_NOALIGN;
        if (ap->flags & XFSMNT_SWALLOC)
                mp->m_flags |= XFS_MOUNT_SWALLOC;
        if (ap->flags & XFSMNT_OSYNCISOSYNC)
                mp->m_flags |= XFS_MOUNT_OSYNCISOSYNC;
        if (ap->flags & XFSMNT_32BITINODES)
                mp->m_flags |= XFS_MOUNT_32BITINODES;

        if (ap->flags & XFSMNT_IOSIZE) {
                if (ap->iosizelog > XFS_MAX_IO_LOG ||
                    ap->iosizelog < XFS_MIN_IO_LOG) {
                        cmn_err(CE_WARN,
                "XFS: invalid log iosize: %d [not %d-%d]",
                                ap->iosizelog, XFS_MIN_IO_LOG,
                                XFS_MAX_IO_LOG);
                        return XFS_ERROR(EINVAL);
                }

                mp->m_flags |= XFS_MOUNT_DFLT_IOSIZE;
                mp->m_readio_log = mp->m_writeio_log = ap->iosizelog;
        }

        if (ap->flags & XFSMNT_IKEEP)
                mp->m_flags |= XFS_MOUNT_IKEEP;
        if (ap->flags & XFSMNT_DIRSYNC)
                mp->m_flags |= XFS_MOUNT_DIRSYNC;
        if (ap->flags & XFSMNT_ATTR2)
                mp->m_flags |= XFS_MOUNT_ATTR2;

        if (ap->flags2 & XFSMNT2_COMPAT_IOSIZE)
                mp->m_flags |= XFS_MOUNT_COMPAT_IOSIZE;

        /*
         * no recovery flag requires a read-only mount
         */
        if (ap->flags & XFSMNT_NORECOVERY) {
                if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
                        cmn_err(CE_WARN,
        "XFS: tried to mount a FS read-write without recovery!");
                        return XFS_ERROR(EINVAL);
                }
                mp->m_flags |= XFS_MOUNT_NORECOVERY;
        }

        if (ap->flags & XFSMNT_NOUUID)
                mp->m_flags |= XFS_MOUNT_NOUUID;
        if (ap->flags & XFSMNT_BARRIER)
                mp->m_flags |= XFS_MOUNT_BARRIER;
        else
                mp->m_flags &= ~XFS_MOUNT_BARRIER;

        if (ap->flags2 & XFSMNT2_FILESTREAMS)
                mp->m_flags |= XFS_MOUNT_FILESTREAMS;

        if (ap->flags & XFSMNT_DMAPI)
                mp->m_flags |= XFS_MOUNT_DMAPI;
        return 0;
}

/*
 * This function fills in xfs_mount_t fields based on mount args.
 * Note: the superblock _has_ now been read in.
 */
STATIC int
xfs_finish_flags(
        struct xfs_mount_args   *ap,
        struct xfs_mount        *mp)
{
        int                     ronly = (mp->m_flags & XFS_MOUNT_RDONLY);

        /* Fail a mount where the logbuf is smaller then the log stripe */
        if (xfs_sb_version_haslogv2(&mp->m_sb)) {
                if ((ap->logbufsize <= 0) &&
                    (mp->m_sb.sb_logsunit > XLOG_BIG_RECORD_BSIZE)) {
                        mp->m_logbsize = mp->m_sb.sb_logsunit;
                } else if (ap->logbufsize > 0 &&
                           ap->logbufsize < mp->m_sb.sb_logsunit) {
                        cmn_err(CE_WARN,
        "XFS: logbuf size must be greater than or equal to log stripe size");
                        return XFS_ERROR(EINVAL);
                }
        } else {
                /* Fail a mount if the logbuf is larger than 32K */
                if (ap->logbufsize > XLOG_BIG_RECORD_BSIZE) {
                        cmn_err(CE_WARN,
        "XFS: logbuf size for version 1 logs must be 16K or 32K");
                        return XFS_ERROR(EINVAL);
                }
        }

        if (xfs_sb_version_hasattr2(&mp->m_sb))
                mp->m_flags |= XFS_MOUNT_ATTR2;

        /*
         * prohibit r/w mounts of read-only filesystems
         */
        if ((mp->m_sb.sb_flags & XFS_SBF_READONLY) && !ronly) {
                cmn_err(CE_WARN,
        "XFS: cannot mount a read-only filesystem as read-write");
                return XFS_ERROR(EROFS);
        }

        /*
         * check for shared mount.
         */
        if (ap->flags & XFSMNT_SHARED) {
                if (!xfs_sb_version_hasshared(&mp->m_sb))
                        return XFS_ERROR(EINVAL);

                /*
                 * For IRIX 6.5, shared mounts must have the shared
                 * version bit set, have the persistent readonly
                 * field set, must be version 0 and can only be mounted
                 * read-only.
                 */
                if (!ronly || !(mp->m_sb.sb_flags & XFS_SBF_READONLY) ||
                     (mp->m_sb.sb_shared_vn != 0))
                        return XFS_ERROR(EINVAL);

                mp->m_flags |= XFS_MOUNT_SHARED;

                /*
                 * Shared XFS V0 can't deal with DMI.  Return EINVAL.
                 */
                if (mp->m_sb.sb_shared_vn == 0 && (ap->flags & XFSMNT_DMAPI))
                        return XFS_ERROR(EINVAL);
        }

        if (ap->flags & XFSMNT_UQUOTA) {
                mp->m_qflags |= (XFS_UQUOTA_ACCT | XFS_UQUOTA_ACTIVE);
                if (ap->flags & XFSMNT_UQUOTAENF)
                        mp->m_qflags |= XFS_UQUOTA_ENFD;
        }

        if (ap->flags & XFSMNT_GQUOTA) {
                mp->m_qflags |= (XFS_GQUOTA_ACCT | XFS_GQUOTA_ACTIVE);
                if (ap->flags & XFSMNT_GQUOTAENF)
                        mp->m_qflags |= XFS_OQUOTA_ENFD;
        } else if (ap->flags & XFSMNT_PQUOTA) {
                mp->m_qflags |= (XFS_PQUOTA_ACCT | XFS_PQUOTA_ACTIVE);
                if (ap->flags & XFSMNT_PQUOTAENF)
                        mp->m_qflags |= XFS_OQUOTA_ENFD;
        }

        return 0;
}

/*
 * xfs_mount
 *
 * The file system configurations are:
 *      (1) device (partition) with data and internal log
 *      (2) logical volume with data and log subvolumes.
 *      (3) logical volume with data, log, and realtime subvolumes.
 *
 * We only have to handle opening the log and realtime volumes here if
 * they are present.  The data subvolume has already been opened by
 * get_sb_bdev() and is stored in vfsp->vfs_super->s_bdev.
 */
int
xfs_mount(
        struct xfs_mount        *mp,
        struct xfs_mount_args   *args,
        cred_t                  *credp)
{
        struct block_device     *ddev, *logdev, *rtdev;
        int                     flags = 0, error;

        ddev = mp->m_super->s_bdev;
        logdev = rtdev = NULL;

        error = xfs_dmops_get(mp, args);
        if (error)
                return error;
        error = xfs_qmops_get(mp, args);
        if (error)
                return error;

        if (args->flags & XFSMNT_QUIET)
                flags |= XFS_MFSI_QUIET;

        /*
         * Open real time and log devices - order is important.
         */
        if (args->logname[0]) {
                error = xfs_blkdev_get(mp, args->logname, &logdev);
                if (error)
                        return error;
        }
        if (args->rtname[0]) {
                error = xfs_blkdev_get(mp, args->rtname, &rtdev);
                if (error) {
                        xfs_blkdev_put(logdev);
                        return error;
                }

                if (rtdev == ddev || rtdev == logdev) {
                        cmn_err(CE_WARN,
        "XFS: Cannot mount filesystem with identical rtdev and ddev/logdev.");
                        xfs_blkdev_put(logdev);
                        xfs_blkdev_put(rtdev);
                        return EINVAL;
                }
        }

        /*
         * Setup xfs_mount buffer target pointers
         */
        error = ENOMEM;
        mp->m_ddev_targp = xfs_alloc_buftarg(ddev, 0);
        if (!mp->m_ddev_targp) {
                xfs_blkdev_put(logdev);
                xfs_blkdev_put(rtdev);
                return error;
        }
        if (rtdev) {
                mp->m_rtdev_targp = xfs_alloc_buftarg(rtdev, 1);
                if (!mp->m_rtdev_targp) {
                        xfs_blkdev_put(logdev);
                        xfs_blkdev_put(rtdev);
                        goto error0;
                }
        }
        mp->m_logdev_targp = (logdev && logdev != ddev) ?
                                xfs_alloc_buftarg(logdev, 1) : mp->m_ddev_targp;
        if (!mp->m_logdev_targp) {
                xfs_blkdev_put(logdev);
                xfs_blkdev_put(rtdev);
                goto error0;
        }

        /*
         * Setup flags based on mount(2) options and then the superblock
         */
        error = xfs_start_flags(args, mp);
        if (error)
                goto error1;
        error = xfs_readsb(mp, flags);
        if (error)
                goto error1;
        error = xfs_finish_flags(args, mp);
        if (error)
                goto error2;

        /*
         * Setup xfs_mount buffer target pointers based on superblock
         */
        error = xfs_setsize_buftarg(mp->m_ddev_targp, mp->m_sb.sb_blocksize,
                                    mp->m_sb.sb_sectsize);
        if (!error && logdev && logdev != ddev) {
                unsigned int    log_sector_size = BBSIZE;

                if (xfs_sb_version_hassector(&mp->m_sb))
                        log_sector_size = mp->m_sb.sb_logsectsize;
                error = xfs_setsize_buftarg(mp->m_logdev_targp,
                                            mp->m_sb.sb_blocksize,
                                            log_sector_size);
        }
        if (!error && rtdev)
                error = xfs_setsize_buftarg(mp->m_rtdev_targp,
                                            mp->m_sb.sb_blocksize,
                                            mp->m_sb.sb_sectsize);
        if (error)
                goto error2;

        if (mp->m_flags & XFS_MOUNT_BARRIER)
                xfs_mountfs_check_barriers(mp);

        if ((error = xfs_filestream_mount(mp)))
                goto error2;

        error = xfs_mountfs(mp, flags);
        if (error)
                goto error2;

        XFS_SEND_MOUNT(mp, DM_RIGHT_NULL, args->mtpt, args->fsname);

        return 0;

error2:
        if (mp->m_sb_bp)
                xfs_freesb(mp);
error1:
        xfs_binval(mp->m_ddev_targp);
        if (logdev && logdev != ddev)
                xfs_binval(mp->m_logdev_targp);
        if (rtdev)
                xfs_binval(mp->m_rtdev_targp);
error0:
        xfs_unmountfs_close(mp, credp);
        xfs_qmops_put(mp);
        xfs_dmops_put(mp);
        return error;
}

int
xfs_unmount(
        xfs_mount_t     *mp,
        int             flags,
        cred_t          *credp)
{
        xfs_inode_t     *rip;
        bhv_vnode_t     *rvp;
        int             unmount_event_wanted = 0;
        int             unmount_event_flags = 0;
        int             xfs_unmountfs_needed = 0;
        int             error;

        rip = mp->m_rootip;
        rvp = XFS_ITOV(rip);

#ifdef HAVE_DMAPI
        if (mp->m_flags & XFS_MOUNT_DMAPI) {
                error = XFS_SEND_PREUNMOUNT(mp,
                                rip, DM_RIGHT_NULL, rip, DM_RIGHT_NULL,
                                NULL, NULL, 0, 0,
                                (mp->m_dmevmask & (1<<DM_EVENT_PREUNMOUNT))?
                                        0:DM_FLAGS_UNWANTED);
                        if (error)
                                return XFS_ERROR(error);
                unmount_event_wanted = 1;
                unmount_event_flags = (mp->m_dmevmask & (1<<DM_EVENT_UNMOUNT))?
                                        0 : DM_FLAGS_UNWANTED;
        }
#endif

        /*
         * Blow away any referenced inode in the filestreams cache.
         * This can and will cause log traffic as inodes go inactive
         * here.
         */
        xfs_filestream_unmount(mp);

        XFS_bflush(mp->m_ddev_targp);
        error = xfs_unmount_flush(mp, 0);
        if (error)
                goto out;

        ASSERT(vn_count(rvp) == 1);

        /*
         * Drop the reference count
         */
        IRELE(rip);

        /*
         * If we're forcing a shutdown, typically because of a media error,
         * we want to make sure we invalidate dirty pages that belong to
         * referenced vnodes as well.
         */
        if (XFS_FORCED_SHUTDOWN(mp)) {
                error = xfs_sync(mp, SYNC_WAIT | SYNC_CLOSE);
                ASSERT(error != EFSCORRUPTED);
        }
        xfs_unmountfs_needed = 1;

out:
        /*      Send DMAPI event, if required.
         *      Then do xfs_unmountfs() if needed.
         *      Then return error (or zero).
         */
        if (unmount_event_wanted) {
                /* Note: mp structure must still exist for
                 * XFS_SEND_UNMOUNT() call.
                 */
                XFS_SEND_UNMOUNT(mp, error == 0 ? rip : NULL,
                        DM_RIGHT_NULL, 0, error, unmount_event_flags);
        }
        if (xfs_unmountfs_needed) {
                /*
                 * Call common unmount function to flush to disk
                 * and free the super block buffer & mount structures.
                 */
                xfs_unmountfs(mp, credp);
                xfs_qmops_put(mp);
                xfs_dmops_put(mp);
                kmem_free(mp, sizeof(xfs_mount_t));
        }

        return XFS_ERROR(error);
}

STATIC void
xfs_quiesce_fs(
        xfs_mount_t             *mp)
{
        int                     count = 0, pincount;

        xfs_flush_buftarg(mp->m_ddev_targp, 0);
        xfs_finish_reclaim_all(mp, 0);

        /* This loop must run at least twice.
         * The first instance of the loop will flush
         * most meta data but that will generate more
         * meta data (typically directory updates).
         * Which then must be flushed and logged before
         * we can write the unmount record.
         */
        do {
                xfs_syncsub(mp, SYNC_INODE_QUIESCE, NULL);
                pincount = xfs_flush_buftarg(mp->m_ddev_targp, 1);
                if (!pincount) {
                        delay(50);
                        count++;
                }
        } while (count < 2);
}

/*
 * Second stage of a quiesce. The data is already synced, now we have to take
 * care of the metadata. New transactions are already blocked, so we need to
 * wait for any remaining transactions to drain out before proceding.
 */
void
xfs_attr_quiesce(
        xfs_mount_t     *mp)
{
        int     error = 0;

        /* wait for all modifications to complete */
        while (atomic_read(&mp->m_active_trans) > 0)
                delay(100);

        /* flush inodes and push all remaining buffers out to disk */
        xfs_quiesce_fs(mp);

        ASSERT_ALWAYS(atomic_read(&mp->m_active_trans) == 0);

        /* Push the superblock and write an unmount record */
        error = xfs_log_sbcount(mp, 1);
        if (error)
                xfs_fs_cmn_err(CE_WARN, mp,
                                "xfs_attr_quiesce: failed to log sb changes. "
                                "Frozen image may not be consistent.");
        xfs_log_unmount_write(mp);
        xfs_unmountfs_writesb(mp);
}

int
xfs_mntupdate(
        struct xfs_mount                *mp,
        int                             *flags,
        struct xfs_mount_args           *args)
{
        if (!(*flags & MS_RDONLY)) {                    /* rw/ro -> rw */
                if (mp->m_flags & XFS_MOUNT_RDONLY)
                        mp->m_flags &= ~XFS_MOUNT_RDONLY;
                if (args->flags & XFSMNT_BARRIER) {
                        mp->m_flags |= XFS_MOUNT_BARRIER;
                        xfs_mountfs_check_barriers(mp);
                } else {
                        mp->m_flags &= ~XFS_MOUNT_BARRIER;
                }
        } else if (!(mp->m_flags & XFS_MOUNT_RDONLY)) { /* rw -> ro */
                xfs_filestream_flush(mp);
                xfs_sync(mp, SYNC_DATA_QUIESCE);
                xfs_attr_quiesce(mp);
                mp->m_flags |= XFS_MOUNT_RDONLY;
        }
        return 0;
}

/*
 * xfs_unmount_flush implements a set of flush operation on special
 * inodes, which are needed as a separate set of operations so that
 * they can be called as part of relocation process.
 */
int
xfs_unmount_flush(
        xfs_mount_t     *mp,            /* Mount structure we are getting
                                           rid of. */
        int             relocation)     /* Called from vfs relocation. */
{
        xfs_inode_t     *rip = mp->m_rootip;
        xfs_inode_t     *rbmip;
        xfs_inode_t     *rsumip = NULL;
        bhv_vnode_t     *rvp = XFS_ITOV(rip);
        int             error;

        xfs_ilock(rip, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
        xfs_iflock(rip);

        /*
         * Flush out the real time inodes.
         */
        if ((rbmip = mp->m_rbmip) != NULL) {
                xfs_ilock(rbmip, XFS_ILOCK_EXCL);
                xfs_iflock(rbmip);
                error = xfs_iflush(rbmip, XFS_IFLUSH_SYNC);
                xfs_iunlock(rbmip, XFS_ILOCK_EXCL);

                if (error == EFSCORRUPTED)
                        goto fscorrupt_out;

                ASSERT(vn_count(XFS_ITOV(rbmip)) == 1);

                rsumip = mp->m_rsumip;
                xfs_ilock(rsumip, XFS_ILOCK_EXCL);
                xfs_iflock(rsumip);
                error = xfs_iflush(rsumip, XFS_IFLUSH_SYNC);
                xfs_iunlock(rsumip, XFS_ILOCK_EXCL);

                if (error == EFSCORRUPTED)
                        goto fscorrupt_out;

                ASSERT(vn_count(XFS_ITOV(rsumip)) == 1);
        }

        /*
         * Synchronously flush root inode to disk
         */
        error = xfs_iflush(rip, XFS_IFLUSH_SYNC);
        if (error == EFSCORRUPTED)
                goto fscorrupt_out2;

        if (vn_count(rvp) != 1 && !relocation) {
                xfs_iunlock(rip, XFS_ILOCK_EXCL);
                return XFS_ERROR(EBUSY);
        }

        /*
         * Release dquot that rootinode, rbmino and rsumino might be holding,
         * flush and purge the quota inodes.
         */
        error = XFS_QM_UNMOUNT(mp);
        if (error == EFSCORRUPTED)
                goto fscorrupt_out2;

        if (rbmip) {
                IRELE(rbmip);
                IRELE(rsumip);
        }

        xfs_iunlock(rip, XFS_ILOCK_EXCL);
        return 0;

fscorrupt_out:
        xfs_ifunlock(rip);

fscorrupt_out2:
        xfs_iunlock(rip, XFS_ILOCK_EXCL);

        return XFS_ERROR(EFSCORRUPTED);
}

/*
 * xfs_sync flushes any pending I/O to file system vfsp.
 *
 * This routine is called by vfs_sync() to make sure that things make it
 * out to disk eventually, on sync() system calls to flush out everything,
 * and when the file system is unmounted.  For the vfs_sync() case, all
 * we really need to do is sync out the log to make all of our meta-data
 * updates permanent (except for timestamps).  For calls from pflushd(),
 * dirty pages are kept moving by calling pdflush() on the inodes
 * containing them.  We also flush the inodes that we can lock without
 * sleeping and the superblock if we can lock it without sleeping from
 * vfs_sync() so that items at the tail of the log are always moving out.
 *
 * Flags:
 *      SYNC_BDFLUSH - We're being called from vfs_sync() so we don't want
 *                     to sleep if we can help it.  All we really need
 *                     to do is ensure that the log is synced at least
 *                     periodically.  We also push the inodes and
 *                     superblock if we can lock them without sleeping
 *                      and they are not pinned.
 *      SYNC_ATTR    - We need to flush the inodes.  If SYNC_BDFLUSH is not
 *                     set, then we really want to lock each inode and flush
 *                     it.
 *      SYNC_WAIT    - All the flushes that take place in this call should
 *                     be synchronous.
 *      SYNC_DELWRI  - This tells us to push dirty pages associated with
 *                     inodes.  SYNC_WAIT and SYNC_BDFLUSH are used to
 *                     determine if they should be flushed sync, async, or
 *                     delwri.
 *      SYNC_CLOSE   - This flag is passed when the system is being
 *                     unmounted.  We should sync and invalidate everything.
 *      SYNC_FSDATA  - This indicates that the caller would like to make
 *                     sure the superblock is safe on disk.  We can ensure
 *                     this by simply making sure the log gets flushed
 *                     if SYNC_BDFLUSH is set, and by actually writing it
 *                     out otherwise.
 *      SYNC_IOWAIT  - The caller wants us to wait for all data I/O to complete
 *                     before we return (including direct I/O). Forms the drain
 *                     side of the write barrier needed to safely quiesce the
 *                     filesystem.
 *
 */
int
xfs_sync(
        xfs_mount_t     *mp,
        int             flags)
{
        int             error;

        /*
         * Get the Quota Manager to flush the dquots.
         *
         * If XFS quota support is not enabled or this filesystem
         * instance does not use quotas XFS_QM_DQSYNC will always
         * return zero.
         */
        error = XFS_QM_DQSYNC(mp, flags);
        if (error) {
                /*
                 * If we got an IO error, we will be shutting down.
                 * So, there's nothing more for us to do here.
                 */
                ASSERT(error != EIO || XFS_FORCED_SHUTDOWN(mp));
                if (XFS_FORCED_SHUTDOWN(mp))
                        return XFS_ERROR(error);
        }

        if (flags & SYNC_IOWAIT)
                xfs_filestream_flush(mp);

        return xfs_syncsub(mp, flags, NULL);
}

/*
 * xfs sync routine for internal use
 *
 * This routine supports all of the flags defined for the generic vfs_sync
 * interface as explained above under xfs_sync.
 *
 */
int
xfs_sync_inodes(
        xfs_mount_t     *mp,
        int             flags,
        int             *bypassed)
{
        xfs_inode_t     *ip = NULL;
        bhv_vnode_t     *vp = NULL;
        int             error;
        int             last_error;
        uint64_t        fflag;
        uint            lock_flags;
        uint            base_lock_flags;
        boolean_t       mount_locked;
        boolean_t       vnode_refed;
        int             preempt;
        xfs_iptr_t      *ipointer;
#ifdef DEBUG
        boolean_t       ipointer_in = B_FALSE;

#define IPOINTER_SET    ipointer_in = B_TRUE
#define IPOINTER_CLR    ipointer_in = B_FALSE
#else
#define IPOINTER_SET
#define IPOINTER_CLR
#endif


/* Insert a marker record into the inode list after inode ip. The list
 * must be locked when this is called. After the call the list will no
 * longer be locked.
 */
#define IPOINTER_INSERT(ip, mp) { \
                ASSERT(ipointer_in == B_FALSE); \
                ipointer->ip_mnext = ip->i_mnext; \
                ipointer->ip_mprev = ip; \
                ip->i_mnext = (xfs_inode_t *)ipointer; \
                ipointer->ip_mnext->i_mprev = (xfs_inode_t *)ipointer; \
                preempt = 0; \
                XFS_MOUNT_IUNLOCK(mp); \
                mount_locked = B_FALSE; \
                IPOINTER_SET; \
        }

/* Remove the marker from the inode list. If the marker was the only item
 * in the list then there are no remaining inodes and we should zero out
 * the whole list. If we are the current head of the list then move the head
 * past us.
 */
#define IPOINTER_REMOVE(ip, mp) { \
                ASSERT(ipointer_in == B_TRUE); \
                if (ipointer->ip_mnext != (xfs_inode_t *)ipointer) { \
                        ip = ipointer->ip_mnext; \
                        ip->i_mprev = ipointer->ip_mprev; \
                        ipointer->ip_mprev->i_mnext = ip; \
                        if (mp->m_inodes == (xfs_inode_t *)ipointer) { \
                                mp->m_inodes = ip; \
                        } \
                } else { \
                        ASSERT(mp->m_inodes == (xfs_inode_t *)ipointer); \
                        mp->m_inodes = NULL; \
                        ip = NULL; \
                } \
                IPOINTER_CLR; \
        }

#define XFS_PREEMPT_MASK        0x7f

        ASSERT(!(flags & SYNC_BDFLUSH));

        if (bypassed)
                *bypassed = 0;
        if (mp->m_flags & XFS_MOUNT_RDONLY)
                return 0;
        error = 0;
        last_error = 0;
        preempt = 0;

        /* Allocate a reference marker */
        ipointer = (xfs_iptr_t *)kmem_zalloc(sizeof(xfs_iptr_t), KM_SLEEP);

        fflag = XFS_B_ASYNC;            /* default is don't wait */
        if (flags & SYNC_DELWRI)
                fflag = XFS_B_DELWRI;
        if (flags & SYNC_WAIT)
                fflag = 0;              /* synchronous overrides all */

        base_lock_flags = XFS_ILOCK_SHARED;
        if (flags & (SYNC_DELWRI | SYNC_CLOSE)) {
                /*
                 * We need the I/O lock if we're going to call any of
                 * the flush/inval routines.
                 */
                base_lock_flags |= XFS_IOLOCK_SHARED;
        }

        XFS_MOUNT_ILOCK(mp);

        ip = mp->m_inodes;

        mount_locked = B_TRUE;
        vnode_refed  = B_FALSE;

        IPOINTER_CLR;

        do {
                ASSERT(ipointer_in == B_FALSE);
                ASSERT(vnode_refed == B_FALSE);

                lock_flags = base_lock_flags;

                /*
                 * There were no inodes in the list, just break out
                 * of the loop.
                 */
                if (ip == NULL) {
                        break;
                }

                /*
                 * We found another sync thread marker - skip it
                 */
                if (ip->i_mount == NULL) {
                        ip = ip->i_mnext;
                        continue;
                }

                vp = XFS_ITOV_NULL(ip);

                /*
                 * If the vnode is gone then this is being torn down,
                 * call reclaim if it is flushed, else let regular flush
                 * code deal with it later in the loop.
                 */

                if (vp == NULL) {
                        /* Skip ones already in reclaim */
                        if (ip->i_flags & XFS_IRECLAIM) {
                                ip = ip->i_mnext;
                                continue;
                        }
                        if (xfs_ilock_nowait(ip, XFS_ILOCK_EXCL) == 0) {
                                ip = ip->i_mnext;
                        } else if ((xfs_ipincount(ip) == 0) &&
                                    xfs_iflock_nowait(ip)) {
                                IPOINTER_INSERT(ip, mp);

                                xfs_finish_reclaim(ip, 1,
                                                XFS_IFLUSH_DELWRI_ELSE_ASYNC);

                                XFS_MOUNT_ILOCK(mp);
                                mount_locked = B_TRUE;
                                IPOINTER_REMOVE(ip, mp);
                        } else {
                                xfs_iunlock(ip, XFS_ILOCK_EXCL);
                                ip = ip->i_mnext;
                        }
                        continue;
                }

                if (VN_BAD(vp)) {
                        ip = ip->i_mnext;
                        continue;
                }

                if (XFS_FORCED_SHUTDOWN(mp) && !(flags & SYNC_CLOSE)) {
                        XFS_MOUNT_IUNLOCK(mp);
                        kmem_free(ipointer, sizeof(xfs_iptr_t));
                        return 0;
                }

                /*
                 * Try to lock without sleeping.  We're out of order with
                 * the inode list lock here, so if we fail we need to drop
                 * the mount lock and try again.  If we're called from
                 * bdflush() here, then don't bother.
                 *
                 * The inode lock here actually coordinates with the
                 * almost spurious inode lock in xfs_ireclaim() to prevent
                 * the vnode we handle here without a reference from
                 * being freed while we reference it.  If we lock the inode
                 * while it's on the mount list here, then the spurious inode
                 * lock in xfs_ireclaim() after the inode is pulled from
                 * the mount list will sleep until we release it here.
                 * This keeps the vnode from being freed while we reference
                 * it.
                 */
                if (xfs_ilock_nowait(ip, lock_flags) == 0) {
                        if (vp == NULL) {
                                ip = ip->i_mnext;
                                continue;
                        }

                        vp = vn_grab(vp);
                        if (vp == NULL) {
                                ip = ip->i_mnext;
                                continue;
                        }

                        IPOINTER_INSERT(ip, mp);
                        xfs_ilock(ip, lock_flags);

                        ASSERT(vp == XFS_ITOV(ip));
                        ASSERT(ip->i_mount == mp);

                        vnode_refed = B_TRUE;
                }

                /* From here on in the loop we may have a marker record
                 * in the inode list.
                 */

                /*
                 * If we have to flush data or wait for I/O completion
                 * we need to drop the ilock that we currently hold.
                 * If we need to drop the lock, insert a marker if we
                 * have not already done so.
                 */
                if ((flags & (SYNC_CLOSE|SYNC_IOWAIT)) ||
                    ((flags & SYNC_DELWRI) && VN_DIRTY(vp))) {
                        if (mount_locked) {
                                IPOINTER_INSERT(ip, mp);
                        }
                        xfs_iunlock(ip, XFS_ILOCK_SHARED);

                        if (flags & SYNC_CLOSE) {
                                /* Shutdown case. Flush and invalidate. */
                                if (XFS_FORCED_SHUTDOWN(mp))
                                        xfs_tosspages(ip, 0, -1,
                                                             FI_REMAPF);
                                else
                                        error = xfs_flushinval_pages(ip,
                                                        0, -1, FI_REMAPF);
                        } else if ((flags & SYNC_DELWRI) && VN_DIRTY(vp)) {
                                error = xfs_flush_pages(ip, 0,
                                                        -1, fflag, FI_NONE);
                        }

                        /*
                         * When freezing, we need to wait ensure all I/O (including direct
                         * I/O) is complete to ensure no further data modification can take
                         * place after this point
                         */
                        if (flags & SYNC_IOWAIT)
                                vn_iowait(ip);

                        xfs_ilock(ip, XFS_ILOCK_SHARED);
                }

                if ((flags & SYNC_ATTR) &&
                    (ip->i_update_core ||
                     (ip->i_itemp && ip->i_itemp->ili_format.ilf_fields))) {
                        if (mount_locked)
                                IPOINTER_INSERT(ip, mp);

                        if (flags & SYNC_WAIT) {
                                xfs_iflock(ip);
                                error = xfs_iflush(ip, XFS_IFLUSH_SYNC);

                        /*
                         * If we can't acquire the flush lock, then the inode
                         * is already being flushed so don't bother waiting.
                         *
                         * If we can lock it then do a delwri flush so we can
                         * combine multiple inode flushes in each disk write.
                         */
                        } else if (xfs_iflock_nowait(ip)) {
                                error = xfs_iflush(ip, XFS_IFLUSH_DELWRI);
                        } else if (bypassed) {
                                (*bypassed)++;
                        }
                }

                if (lock_flags != 0) {
                        xfs_iunlock(ip, lock_flags);
                }

                if (vnode_refed) {
                        /*
                         * If we had to take a reference on the vnode
                         * above, then wait until after we've unlocked
                         * the inode to release the reference.  This is
                         * because we can be already holding the inode
                         * lock when IRELE() calls xfs_inactive().
                         *
                         * Make sure to drop the mount lock before calling
                         * IRELE() so that we don't trip over ourselves if
                         * we have to go for the mount lock again in the
                         * inactive code.
                         */
                        if (mount_locked) {
                                IPOINTER_INSERT(ip, mp);
                        }

                        IRELE(ip);

                        vnode_refed = B_FALSE;
                }

                if (error) {
                        last_error = error;
                }

                /*
                 * bail out if the filesystem is corrupted.
                 */
                if (error == EFSCORRUPTED)  {
                        if (!mount_locked) {
                                XFS_MOUNT_ILOCK(mp);
                                IPOINTER_REMOVE(ip, mp);
                        }
                        XFS_MOUNT_IUNLOCK(mp);
                        ASSERT(ipointer_in == B_FALSE);
                        kmem_free(ipointer, sizeof(xfs_iptr_t));
                        return XFS_ERROR(error);
                }

                /* Let other threads have a chance at the mount lock
                 * if we have looped many times without dropping the
                 * lock.
                 */
                if ((++preempt & XFS_PREEMPT_MASK) == 0) {
                        if (mount_locked) {
                                IPOINTER_INSERT(ip, mp);
                        }
                }

                if (mount_locked == B_FALSE) {
                        XFS_MOUNT_ILOCK(mp);
                        mount_locked = B_TRUE;
                        IPOINTER_REMOVE(ip, mp);
                        continue;
                }

                ASSERT(ipointer_in == B_FALSE);
                ip = ip->i_mnext;

        } while (ip != mp->m_inodes);

        XFS_MOUNT_IUNLOCK(mp);

        ASSERT(ipointer_in == B_FALSE);

        kmem_free(ipointer, sizeof(xfs_iptr_t));
        return XFS_ERROR(last_error);
}

/*
 * xfs sync routine for internal use
 *
 * This routine supports all of the flags defined for the generic vfs_sync
 * interface as explained above under xfs_sync.
 *
 */
int
xfs_syncsub(
        xfs_mount_t     *mp,
        int             flags,
        int             *bypassed)
{
        int             error = 0;
        int             last_error = 0;
        uint            log_flags = XFS_LOG_FORCE;
        xfs_buf_t       *bp;
        xfs_buf_log_item_t      *bip;

        /*
         * Sync out the log.  This ensures that the log is periodically
         * flushed even if there is not enough activity to fill it up.
         */
        if (flags & SYNC_WAIT)
                log_flags |= XFS_LOG_SYNC;

        xfs_log_force(mp, (xfs_lsn_t)0, log_flags);

        if (flags & (SYNC_ATTR|SYNC_DELWRI)) {
                if (flags & SYNC_BDFLUSH)
                        xfs_finish_reclaim_all(mp, 1);
                else
                        error = xfs_sync_inodes(mp, flags, bypassed);
        }

        /*
         * Flushing out dirty data above probably generated more
         * log activity, so if this isn't vfs_sync() then flush
         * the log again.
         */
        if (flags & SYNC_DELWRI) {
                xfs_log_force(mp, (xfs_lsn_t)0, log_flags);
        }

        if (flags & SYNC_FSDATA) {
                /*
                 * If this is vfs_sync() then only sync the superblock
                 * if we can lock it without sleeping and it is not pinned.
                 */
                if (flags & SYNC_BDFLUSH) {
                        bp = xfs_getsb(mp, XFS_BUF_TRYLOCK);
                        if (bp != NULL) {
                                bip = XFS_BUF_FSPRIVATE(bp,xfs_buf_log_item_t*);
                                if ((bip != NULL) &&
                                    xfs_buf_item_dirty(bip)) {
                                        if (!(XFS_BUF_ISPINNED(bp))) {
                                                XFS_BUF_ASYNC(bp);
                                                error = xfs_bwrite(mp, bp);
                                        } else {
                                                xfs_buf_relse(bp);
                                        }
                                } else {
                                        xfs_buf_relse(bp);
                                }
                        }
                } else {
                        bp = xfs_getsb(mp, 0);
                        /*
                         * If the buffer is pinned then push on the log so
                         * we won't get stuck waiting in the write for
                         * someone, maybe ourselves, to flush the log.
                         * Even though we just pushed the log above, we
                         * did not have the superblock buffer locked at
                         * that point so it can become pinned in between
                         * there and here.
                         */
                        if (XFS_BUF_ISPINNED(bp))
                                xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE);
                        if (flags & SYNC_WAIT)
                                XFS_BUF_UNASYNC(bp);
                        else
                                XFS_BUF_ASYNC(bp);
                        error = xfs_bwrite(mp, bp);
                }
                if (error) {
                        last_error = error;
                }
        }

        /*
         * Now check to see if the log needs a "dummy" transaction.
         */
        if (!(flags & SYNC_REMOUNT) && xfs_log_need_covered(mp)) {
                xfs_trans_t *tp;
                xfs_inode_t *ip;

                /*
                 * Put a dummy transaction in the log to tell
                 * recovery that all others are OK.
                 */
                tp = xfs_trans_alloc(mp, XFS_TRANS_DUMMY1);
                if ((error = xfs_trans_reserve(tp, 0,
                                XFS_ICHANGE_LOG_RES(mp),
                                0, 0, 0)))  {
                        xfs_trans_cancel(tp, 0);
                        return error;
                }

                ip = mp->m_rootip;
                xfs_ilock(ip, XFS_ILOCK_EXCL);

                xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
                xfs_trans_ihold(tp, ip);
                xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
                error = xfs_trans_commit(tp, 0);
                xfs_iunlock(ip, XFS_ILOCK_EXCL);
                xfs_log_force(mp, (xfs_lsn_t)0, log_flags);
        }

        /*
         * When shutting down, we need to insure that the AIL is pushed
         * to disk or the filesystem can appear corrupt from the PROM.
         */
        if ((flags & (SYNC_CLOSE|SYNC_WAIT)) == (SYNC_CLOSE|SYNC_WAIT)) {
                XFS_bflush(mp->m_ddev_targp);
                if (mp->m_rtdev_targp) {
                        XFS_bflush(mp->m_rtdev_targp);
                }
        }

        return XFS_ERROR(last_error);
}