xfs: introduce a xfssyncd workqueue

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

/*
 * Copyright (c) 2000-2006 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_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_alloc.h"
#include "xfs_quota.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_btree_trace.h"
#include "xfs_ialloc.h"
#include "xfs_bmap.h"
#include "xfs_rtalloc.h"
#include "xfs_error.h"
#include "xfs_itable.h"
#include "xfs_fsops.h"
#include "xfs_attr.h"
#include "xfs_buf_item.h"
#include "xfs_utils.h"
#include "xfs_vnodeops.h"
#include "xfs_log_priv.h"
#include "xfs_trans_priv.h"
#include "xfs_filestream.h"
#include "xfs_da_btree.h"
#include "xfs_extfree_item.h"
#include "xfs_mru_cache.h"
#include "xfs_inode_item.h"
#include "xfs_sync.h"
#include "xfs_trace.h"

#include <linux/namei.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/mount.h>
#include <linux/mempool.h>
#include <linux/writeback.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/parser.h>

static const struct super_operations xfs_super_operations;
static kmem_zone_t *xfs_ioend_zone;
mempool_t *xfs_ioend_pool;

#define MNTOPT_LOGBUFS  "logbufs"       /* number of XFS log buffers */
#define MNTOPT_LOGBSIZE "logbsize"      /* size of XFS log buffers */
#define MNTOPT_LOGDEV   "logdev"        /* log device */
#define MNTOPT_RTDEV    "rtdev"         /* realtime I/O device */
#define MNTOPT_BIOSIZE  "biosize"       /* log2 of preferred buffered io size */
#define MNTOPT_WSYNC    "wsync"         /* safe-mode nfs compatible mount */
#define MNTOPT_NOALIGN  "noalign"       /* turn off stripe alignment */
#define MNTOPT_SWALLOC  "swalloc"       /* turn on stripe width allocation */
#define MNTOPT_SUNIT    "sunit"         /* data volume stripe unit */
#define MNTOPT_SWIDTH   "swidth"        /* data volume stripe width */
#define MNTOPT_NOUUID   "nouuid"        /* ignore filesystem UUID */
#define MNTOPT_MTPT     "mtpt"          /* filesystem mount point */
#define MNTOPT_GRPID    "grpid"         /* group-ID from parent directory */
#define MNTOPT_NOGRPID  "nogrpid"       /* group-ID from current process */
#define MNTOPT_BSDGROUPS    "bsdgroups"    /* group-ID from parent directory */
#define MNTOPT_SYSVGROUPS   "sysvgroups"   /* group-ID from current process */
#define MNTOPT_ALLOCSIZE    "allocsize"    /* preferred allocation size */
#define MNTOPT_NORECOVERY   "norecovery"   /* don't run XFS recovery */
#define MNTOPT_BARRIER  "barrier"       /* use writer barriers for log write and
                                         * unwritten extent conversion */
#define MNTOPT_NOBARRIER "nobarrier"    /* .. disable */
#define MNTOPT_64BITINODE   "inode64"   /* inodes can be allocated anywhere */
#define MNTOPT_IKEEP    "ikeep"         /* do not free empty inode clusters */
#define MNTOPT_NOIKEEP  "noikeep"       /* free empty inode clusters */
#define MNTOPT_LARGEIO     "largeio"    /* report large I/O sizes in stat() */
#define MNTOPT_NOLARGEIO   "nolargeio"  /* do not report large I/O sizes
                                         * in stat(). */
#define MNTOPT_ATTR2    "attr2"         /* do use attr2 attribute format */
#define MNTOPT_NOATTR2  "noattr2"       /* do not use attr2 attribute format */
#define MNTOPT_FILESTREAM  "filestreams" /* use filestreams allocator */
#define MNTOPT_QUOTA    "quota"         /* disk quotas (user) */
#define MNTOPT_NOQUOTA  "noquota"       /* no quotas */
#define MNTOPT_USRQUOTA "usrquota"      /* user quota enabled */
#define MNTOPT_GRPQUOTA "grpquota"      /* group quota enabled */
#define MNTOPT_PRJQUOTA "prjquota"      /* project quota enabled */
#define MNTOPT_UQUOTA   "uquota"        /* user quota (IRIX variant) */
#define MNTOPT_GQUOTA   "gquota"        /* group quota (IRIX variant) */
#define MNTOPT_PQUOTA   "pquota"        /* project quota (IRIX variant) */
#define MNTOPT_UQUOTANOENF "uqnoenforce"/* user quota limit enforcement */
#define MNTOPT_GQUOTANOENF "gqnoenforce"/* group quota limit enforcement */
#define MNTOPT_PQUOTANOENF "pqnoenforce"/* project quota limit enforcement */
#define MNTOPT_QUOTANOENF  "qnoenforce" /* same as uqnoenforce */
#define MNTOPT_DELAYLOG   "delaylog"    /* Delayed loging enabled */
#define MNTOPT_NODELAYLOG "nodelaylog"  /* Delayed loging disabled */

/*
 * Table driven mount option parser.
 *
 * Currently only used for remount, but it will be used for mount
 * in the future, too.
 */
enum {
        Opt_barrier, Opt_nobarrier, Opt_err
};

static const match_table_t tokens = {
        {Opt_barrier, "barrier"},
        {Opt_nobarrier, "nobarrier"},
        {Opt_err, NULL}
};


STATIC unsigned long
suffix_strtoul(char *s, char **endp, unsigned int base)
{
        int     last, shift_left_factor = 0;
        char    *value = s;

        last = strlen(value) - 1;
        if (value[last] == 'K' || value[last] == 'k') {
                shift_left_factor = 10;
                value[last] = '\0';
        }
        if (value[last] == 'M' || value[last] == 'm') {
                shift_left_factor = 20;
                value[last] = '\0';
        }
        if (value[last] == 'G' || value[last] == 'g') {
                shift_left_factor = 30;
                value[last] = '\0';
        }

        return simple_strtoul((const char *)s, endp, base) << shift_left_factor;
}

/*
 * This function fills in xfs_mount_t fields based on mount args.
 * Note: the superblock has _not_ yet been read in.
 *
 * Note that this function leaks the various device name allocations on
 * failure.  The caller takes care of them.
 */
STATIC int
xfs_parseargs(
        struct xfs_mount        *mp,
        char                    *options)
{
        struct super_block      *sb = mp->m_super;
        char                    *this_char, *value, *eov;
        int                     dsunit = 0;
        int                     dswidth = 0;
        int                     iosize = 0;
        __uint8_t               iosizelog = 0;

        /*
         * set up the mount name first so all the errors will refer to the
         * correct device.
         */
        mp->m_fsname = kstrndup(sb->s_id, MAXNAMELEN, GFP_KERNEL);
        if (!mp->m_fsname)
                return ENOMEM;
        mp->m_fsname_len = strlen(mp->m_fsname) + 1;

        /*
         * Copy binary VFS mount flags we are interested in.
         */
        if (sb->s_flags & MS_RDONLY)
                mp->m_flags |= XFS_MOUNT_RDONLY;
        if (sb->s_flags & MS_DIRSYNC)
                mp->m_flags |= XFS_MOUNT_DIRSYNC;
        if (sb->s_flags & MS_SYNCHRONOUS)
                mp->m_flags |= XFS_MOUNT_WSYNC;

        /*
         * Set some default flags that could be cleared by the mount option
         * parsing.
         */
        mp->m_flags |= XFS_MOUNT_BARRIER;
        mp->m_flags |= XFS_MOUNT_COMPAT_IOSIZE;
        mp->m_flags |= XFS_MOUNT_SMALL_INUMS;
        mp->m_flags |= XFS_MOUNT_DELAYLOG;

        /*
         * These can be overridden by the mount option parsing.
         */
        mp->m_logbufs = -1;
        mp->m_logbsize = -1;

        if (!options)
                goto done;

        while ((this_char = strsep(&options, ",")) != NULL) {
                if (!*this_char)
                        continue;
                if ((value = strchr(this_char, '=')) != NULL)
                        *value++ = 0;

                if (!strcmp(this_char, MNTOPT_LOGBUFS)) {
                        if (!value || !*value) {
                                xfs_warn(mp, "%s option requires an argument",
                                        this_char);
                                return EINVAL;
                        }
                        mp->m_logbufs = simple_strtoul(value, &eov, 10);
                } else if (!strcmp(this_char, MNTOPT_LOGBSIZE)) {
                        if (!value || !*value) {
                                xfs_warn(mp, "%s option requires an argument",
                                        this_char);
                                return EINVAL;
                        }
                        mp->m_logbsize = suffix_strtoul(value, &eov, 10);
                } else if (!strcmp(this_char, MNTOPT_LOGDEV)) {
                        if (!value || !*value) {
                                xfs_warn(mp, "%s option requires an argument",
                                        this_char);
                                return EINVAL;
                        }
                        mp->m_logname = kstrndup(value, MAXNAMELEN, GFP_KERNEL);
                        if (!mp->m_logname)
                                return ENOMEM;
                } else if (!strcmp(this_char, MNTOPT_MTPT)) {
                        xfs_warn(mp, "%s option not allowed on this system",
                                this_char);
                        return EINVAL;
                } else if (!strcmp(this_char, MNTOPT_RTDEV)) {
                        if (!value || !*value) {
                                xfs_warn(mp, "%s option requires an argument",
                                        this_char);
                                return EINVAL;
                        }
                        mp->m_rtname = kstrndup(value, MAXNAMELEN, GFP_KERNEL);
                        if (!mp->m_rtname)
                                return ENOMEM;
                } else if (!strcmp(this_char, MNTOPT_BIOSIZE)) {
                        if (!value || !*value) {
                                xfs_warn(mp, "%s option requires an argument",
                                        this_char);
                                return EINVAL;
                        }
                        iosize = simple_strtoul(value, &eov, 10);
                        iosizelog = ffs(iosize) - 1;
                } else if (!strcmp(this_char, MNTOPT_ALLOCSIZE)) {
                        if (!value || !*value) {
                                xfs_warn(mp, "%s option requires an argument",
                                        this_char);
                                return EINVAL;
                        }
                        iosize = suffix_strtoul(value, &eov, 10);
                        iosizelog = ffs(iosize) - 1;
                } else if (!strcmp(this_char, MNTOPT_GRPID) ||
                           !strcmp(this_char, MNTOPT_BSDGROUPS)) {
                        mp->m_flags |= XFS_MOUNT_GRPID;
                } else if (!strcmp(this_char, MNTOPT_NOGRPID) ||
                           !strcmp(this_char, MNTOPT_SYSVGROUPS)) {
                        mp->m_flags &= ~XFS_MOUNT_GRPID;
                } else if (!strcmp(this_char, MNTOPT_WSYNC)) {
                        mp->m_flags |= XFS_MOUNT_WSYNC;
                } else if (!strcmp(this_char, MNTOPT_NORECOVERY)) {
                        mp->m_flags |= XFS_MOUNT_NORECOVERY;
                } else if (!strcmp(this_char, MNTOPT_NOALIGN)) {
                        mp->m_flags |= XFS_MOUNT_NOALIGN;
                } else if (!strcmp(this_char, MNTOPT_SWALLOC)) {
                        mp->m_flags |= XFS_MOUNT_SWALLOC;
                } else if (!strcmp(this_char, MNTOPT_SUNIT)) {
                        if (!value || !*value) {
                                xfs_warn(mp, "%s option requires an argument",
                                        this_char);
                                return EINVAL;
                        }
                        dsunit = simple_strtoul(value, &eov, 10);
                } else if (!strcmp(this_char, MNTOPT_SWIDTH)) {
                        if (!value || !*value) {
                                xfs_warn(mp, "%s option requires an argument",
                                        this_char);
                                return EINVAL;
                        }
                        dswidth = simple_strtoul(value, &eov, 10);
                } else if (!strcmp(this_char, MNTOPT_64BITINODE)) {
                        mp->m_flags &= ~XFS_MOUNT_SMALL_INUMS;
#if !XFS_BIG_INUMS
                        xfs_warn(mp, "%s option not allowed on this system",
                                this_char);
                        return EINVAL;
#endif
                } else if (!strcmp(this_char, MNTOPT_NOUUID)) {
                        mp->m_flags |= XFS_MOUNT_NOUUID;
                } else if (!strcmp(this_char, MNTOPT_BARRIER)) {
                        mp->m_flags |= XFS_MOUNT_BARRIER;
                } else if (!strcmp(this_char, MNTOPT_NOBARRIER)) {
                        mp->m_flags &= ~XFS_MOUNT_BARRIER;
                } else if (!strcmp(this_char, MNTOPT_IKEEP)) {
                        mp->m_flags |= XFS_MOUNT_IKEEP;
                } else if (!strcmp(this_char, MNTOPT_NOIKEEP)) {
                        mp->m_flags &= ~XFS_MOUNT_IKEEP;
                } else if (!strcmp(this_char, MNTOPT_LARGEIO)) {
                        mp->m_flags &= ~XFS_MOUNT_COMPAT_IOSIZE;
                } else if (!strcmp(this_char, MNTOPT_NOLARGEIO)) {
                        mp->m_flags |= XFS_MOUNT_COMPAT_IOSIZE;
                } else if (!strcmp(this_char, MNTOPT_ATTR2)) {
                        mp->m_flags |= XFS_MOUNT_ATTR2;
                } else if (!strcmp(this_char, MNTOPT_NOATTR2)) {
                        mp->m_flags &= ~XFS_MOUNT_ATTR2;
                        mp->m_flags |= XFS_MOUNT_NOATTR2;
                } else if (!strcmp(this_char, MNTOPT_FILESTREAM)) {
                        mp->m_flags |= XFS_MOUNT_FILESTREAMS;
                } else if (!strcmp(this_char, MNTOPT_NOQUOTA)) {
                        mp->m_qflags &= ~(XFS_UQUOTA_ACCT | XFS_UQUOTA_ACTIVE |
                                          XFS_GQUOTA_ACCT | XFS_GQUOTA_ACTIVE |
                                          XFS_PQUOTA_ACCT | XFS_PQUOTA_ACTIVE |
                                          XFS_UQUOTA_ENFD | XFS_OQUOTA_ENFD);
                } else if (!strcmp(this_char, MNTOPT_QUOTA) ||
                           !strcmp(this_char, MNTOPT_UQUOTA) ||
                           !strcmp(this_char, MNTOPT_USRQUOTA)) {
                        mp->m_qflags |= (XFS_UQUOTA_ACCT | XFS_UQUOTA_ACTIVE |
                                         XFS_UQUOTA_ENFD);
                } else if (!strcmp(this_char, MNTOPT_QUOTANOENF) ||
                           !strcmp(this_char, MNTOPT_UQUOTANOENF)) {
                        mp->m_qflags |= (XFS_UQUOTA_ACCT | XFS_UQUOTA_ACTIVE);
                        mp->m_qflags &= ~XFS_UQUOTA_ENFD;
                } else if (!strcmp(this_char, MNTOPT_PQUOTA) ||
                           !strcmp(this_char, MNTOPT_PRJQUOTA)) {
                        mp->m_qflags |= (XFS_PQUOTA_ACCT | XFS_PQUOTA_ACTIVE |
                                         XFS_OQUOTA_ENFD);
                } else if (!strcmp(this_char, MNTOPT_PQUOTANOENF)) {
                        mp->m_qflags |= (XFS_PQUOTA_ACCT | XFS_PQUOTA_ACTIVE);
                        mp->m_qflags &= ~XFS_OQUOTA_ENFD;
                } else if (!strcmp(this_char, MNTOPT_GQUOTA) ||
                           !strcmp(this_char, MNTOPT_GRPQUOTA)) {
                        mp->m_qflags |= (XFS_GQUOTA_ACCT | XFS_GQUOTA_ACTIVE |
                                         XFS_OQUOTA_ENFD);
                } else if (!strcmp(this_char, MNTOPT_GQUOTANOENF)) {
                        mp->m_qflags |= (XFS_GQUOTA_ACCT | XFS_GQUOTA_ACTIVE);
                        mp->m_qflags &= ~XFS_OQUOTA_ENFD;
                } else if (!strcmp(this_char, MNTOPT_DELAYLOG)) {
                        mp->m_flags |= XFS_MOUNT_DELAYLOG;
                } else if (!strcmp(this_char, MNTOPT_NODELAYLOG)) {
                        mp->m_flags &= ~XFS_MOUNT_DELAYLOG;
                } else if (!strcmp(this_char, "ihashsize")) {
                        xfs_warn(mp,
        "ihashsize no longer used, option is deprecated.");
                } else if (!strcmp(this_char, "osyncisdsync")) {
                        xfs_warn(mp,
        "osyncisdsync has no effect, option is deprecated.");
                } else if (!strcmp(this_char, "osyncisosync")) {
                        xfs_warn(mp,
        "osyncisosync has no effect, option is deprecated.");
                } else if (!strcmp(this_char, "irixsgid")) {
                        xfs_warn(mp,
        "irixsgid is now a sysctl(2) variable, option is deprecated.");
                } else {
                        xfs_warn(mp, "unknown mount option [%s].", this_char);
                        return EINVAL;
                }
        }

        /*
         * no recovery flag requires a read-only mount
         */
        if ((mp->m_flags & XFS_MOUNT_NORECOVERY) &&
            !(mp->m_flags & XFS_MOUNT_RDONLY)) {
                xfs_warn(mp, "no-recovery mounts must be read-only.");
                return EINVAL;
        }

        if ((mp->m_flags & XFS_MOUNT_NOALIGN) && (dsunit || dswidth)) {
                xfs_warn(mp,
        "sunit and swidth options incompatible with the noalign option");
                return EINVAL;
        }

#ifndef CONFIG_XFS_QUOTA
        if (XFS_IS_QUOTA_RUNNING(mp)) {
                xfs_warn(mp, "quota support not available in this kernel.");
                return EINVAL;
        }
#endif

        if ((mp->m_qflags & (XFS_GQUOTA_ACCT | XFS_GQUOTA_ACTIVE)) &&
            (mp->m_qflags & (XFS_PQUOTA_ACCT | XFS_PQUOTA_ACTIVE))) {
                xfs_warn(mp, "cannot mount with both project and group quota");
                return EINVAL;
        }

        if ((dsunit && !dswidth) || (!dsunit && dswidth)) {
                xfs_warn(mp, "sunit and swidth must be specified together");
                return EINVAL;
        }

        if (dsunit && (dswidth % dsunit != 0)) {
                xfs_warn(mp,
        "stripe width (%d) must be a multiple of the stripe unit (%d)",
                        dswidth, dsunit);
                return EINVAL;
        }

done:
        if (!(mp->m_flags & XFS_MOUNT_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.
                 */
                if (dsunit) {
                        mp->m_dalign = dsunit;
                        mp->m_flags |= XFS_MOUNT_RETERR;
                }

                if (dswidth)
                        mp->m_swidth = dswidth;
        }

        if (mp->m_logbufs != -1 &&
            mp->m_logbufs != 0 &&
            (mp->m_logbufs < XLOG_MIN_ICLOGS ||
             mp->m_logbufs > XLOG_MAX_ICLOGS)) {
                xfs_warn(mp, "invalid logbufs value: %d [not %d-%d]",
                        mp->m_logbufs, XLOG_MIN_ICLOGS, XLOG_MAX_ICLOGS);
                return XFS_ERROR(EINVAL);
        }
        if (mp->m_logbsize != -1 &&
            mp->m_logbsize !=  0 &&
            (mp->m_logbsize < XLOG_MIN_RECORD_BSIZE ||
             mp->m_logbsize > XLOG_MAX_RECORD_BSIZE ||
             !is_power_of_2(mp->m_logbsize))) {
                xfs_warn(mp,
                        "invalid logbufsize: %d [not 16k,32k,64k,128k or 256k]",
                        mp->m_logbsize);
                return XFS_ERROR(EINVAL);
        }

        if (iosizelog) {
                if (iosizelog > XFS_MAX_IO_LOG ||
                    iosizelog < XFS_MIN_IO_LOG) {
                        xfs_warn(mp, "invalid log iosize: %d [not %d-%d]",
                                iosizelog, XFS_MIN_IO_LOG,
                                XFS_MAX_IO_LOG);
                        return XFS_ERROR(EINVAL);
                }

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

        return 0;
}

struct proc_xfs_info {
        int     flag;
        char    *str;
};

STATIC int
xfs_showargs(
        struct xfs_mount        *mp,
        struct seq_file         *m)
{
        static struct proc_xfs_info xfs_info_set[] = {
                /* the few simple ones we can get from the mount struct */
                { XFS_MOUNT_IKEEP,              "," MNTOPT_IKEEP },
                { XFS_MOUNT_WSYNC,              "," MNTOPT_WSYNC },
                { XFS_MOUNT_NOALIGN,            "," MNTOPT_NOALIGN },
                { XFS_MOUNT_SWALLOC,            "," MNTOPT_SWALLOC },
                { XFS_MOUNT_NOUUID,             "," MNTOPT_NOUUID },
                { XFS_MOUNT_NORECOVERY,         "," MNTOPT_NORECOVERY },
                { XFS_MOUNT_ATTR2,              "," MNTOPT_ATTR2 },
                { XFS_MOUNT_FILESTREAMS,        "," MNTOPT_FILESTREAM },
                { XFS_MOUNT_GRPID,              "," MNTOPT_GRPID },
                { XFS_MOUNT_DELAYLOG,           "," MNTOPT_DELAYLOG },
                { 0, NULL }
        };
        static struct proc_xfs_info xfs_info_unset[] = {
                /* the few simple ones we can get from the mount struct */
                { XFS_MOUNT_COMPAT_IOSIZE,      "," MNTOPT_LARGEIO },
                { XFS_MOUNT_BARRIER,            "," MNTOPT_NOBARRIER },
                { XFS_MOUNT_SMALL_INUMS,        "," MNTOPT_64BITINODE },
                { 0, NULL }
        };
        struct proc_xfs_info    *xfs_infop;

        for (xfs_infop = xfs_info_set; xfs_infop->flag; xfs_infop++) {
                if (mp->m_flags & xfs_infop->flag)
                        seq_puts(m, xfs_infop->str);
        }
        for (xfs_infop = xfs_info_unset; xfs_infop->flag; xfs_infop++) {
                if (!(mp->m_flags & xfs_infop->flag))
                        seq_puts(m, xfs_infop->str);
        }

        if (mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)
                seq_printf(m, "," MNTOPT_ALLOCSIZE "=%dk",
                                (int)(1 << mp->m_writeio_log) >> 10);

        if (mp->m_logbufs > 0)
                seq_printf(m, "," MNTOPT_LOGBUFS "=%d", mp->m_logbufs);
        if (mp->m_logbsize > 0)
                seq_printf(m, "," MNTOPT_LOGBSIZE "=%dk", mp->m_logbsize >> 10);

        if (mp->m_logname)
                seq_printf(m, "," MNTOPT_LOGDEV "=%s", mp->m_logname);
        if (mp->m_rtname)
                seq_printf(m, "," MNTOPT_RTDEV "=%s", mp->m_rtname);

        if (mp->m_dalign > 0)
                seq_printf(m, "," MNTOPT_SUNIT "=%d",
                                (int)XFS_FSB_TO_BB(mp, mp->m_dalign));
        if (mp->m_swidth > 0)
                seq_printf(m, "," MNTOPT_SWIDTH "=%d",
                                (int)XFS_FSB_TO_BB(mp, mp->m_swidth));

        if (mp->m_qflags & (XFS_UQUOTA_ACCT|XFS_UQUOTA_ENFD))
                seq_puts(m, "," MNTOPT_USRQUOTA);
        else if (mp->m_qflags & XFS_UQUOTA_ACCT)
                seq_puts(m, "," MNTOPT_UQUOTANOENF);

        /* Either project or group quotas can be active, not both */

        if (mp->m_qflags & XFS_PQUOTA_ACCT) {
                if (mp->m_qflags & XFS_OQUOTA_ENFD)
                        seq_puts(m, "," MNTOPT_PRJQUOTA);
                else
                        seq_puts(m, "," MNTOPT_PQUOTANOENF);
        } else if (mp->m_qflags & XFS_GQUOTA_ACCT) {
                if (mp->m_qflags & XFS_OQUOTA_ENFD)
                        seq_puts(m, "," MNTOPT_GRPQUOTA);
                else
                        seq_puts(m, "," MNTOPT_GQUOTANOENF);
        }

        if (!(mp->m_qflags & XFS_ALL_QUOTA_ACCT))
                seq_puts(m, "," MNTOPT_NOQUOTA);

        return 0;
}
__uint64_t
xfs_max_file_offset(
        unsigned int            blockshift)
{
        unsigned int            pagefactor = 1;
        unsigned int            bitshift = BITS_PER_LONG - 1;

        /* Figure out maximum filesize, on Linux this can depend on
         * the filesystem blocksize (on 32 bit platforms).
         * __block_write_begin does this in an [unsigned] long...
         *      page->index << (PAGE_CACHE_SHIFT - bbits)
         * So, for page sized blocks (4K on 32 bit platforms),
         * this wraps at around 8Tb (hence MAX_LFS_FILESIZE which is
         *      (((u64)PAGE_CACHE_SIZE << (BITS_PER_LONG-1))-1)
         * but for smaller blocksizes it is less (bbits = log2 bsize).
         * Note1: get_block_t takes a long (implicit cast from above)
         * Note2: The Large Block Device (LBD and HAVE_SECTOR_T) patch
         * can optionally convert the [unsigned] long from above into
         * an [unsigned] long long.
         */

#if BITS_PER_LONG == 32
# if defined(CONFIG_LBDAF)
        ASSERT(sizeof(sector_t) == 8);
        pagefactor = PAGE_CACHE_SIZE;
        bitshift = BITS_PER_LONG;
# else
        pagefactor = PAGE_CACHE_SIZE >> (PAGE_CACHE_SHIFT - blockshift);
# endif
#endif

        return (((__uint64_t)pagefactor) << bitshift) - 1;
}

STATIC int
xfs_blkdev_get(
        xfs_mount_t             *mp,
        const char              *name,
        struct block_device     **bdevp)
{
        int                     error = 0;

        *bdevp = blkdev_get_by_path(name, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
                                    mp);
        if (IS_ERR(*bdevp)) {
                error = PTR_ERR(*bdevp);
                xfs_warn(mp, "Invalid device [%s], error=%d\n", name, error);
        }

        return -error;
}

STATIC void
xfs_blkdev_put(
        struct block_device     *bdev)
{
        if (bdev)
                blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
}

/*
 * Try to write out the superblock using barriers.
 */
STATIC int
xfs_barrier_test(
        xfs_mount_t     *mp)
{
        xfs_buf_t       *sbp = xfs_getsb(mp, 0);
        int             error;

        XFS_BUF_UNDONE(sbp);
        XFS_BUF_UNREAD(sbp);
        XFS_BUF_UNDELAYWRITE(sbp);
        XFS_BUF_WRITE(sbp);
        XFS_BUF_UNASYNC(sbp);
        XFS_BUF_ORDERED(sbp);

        xfsbdstrat(mp, sbp);
        error = xfs_buf_iowait(sbp);

        /*
         * Clear all the flags we set and possible error state in the
         * buffer.  We only did the write to try out whether barriers
         * worked and shouldn't leave any traces in the superblock
         * buffer.
         */
        XFS_BUF_DONE(sbp);
        XFS_BUF_ERROR(sbp, 0);
        XFS_BUF_UNORDERED(sbp);

        xfs_buf_relse(sbp);
        return error;
}

STATIC void
xfs_mountfs_check_barriers(xfs_mount_t *mp)
{
        int error;

        if (mp->m_logdev_targp != mp->m_ddev_targp) {
                xfs_notice(mp,
                  "Disabling barriers, not supported with external log device");
                mp->m_flags &= ~XFS_MOUNT_BARRIER;
                return;
        }

        if (xfs_readonly_buftarg(mp->m_ddev_targp)) {
                xfs_notice(mp,
                        "Disabling barriers, underlying device is readonly");
                mp->m_flags &= ~XFS_MOUNT_BARRIER;
                return;
        }

        error = xfs_barrier_test(mp);
        if (error) {
                xfs_notice(mp,
                        "Disabling barriers, trial barrier write failed");
                mp->m_flags &= ~XFS_MOUNT_BARRIER;
                return;
        }
}

void
xfs_blkdev_issue_flush(
        xfs_buftarg_t           *buftarg)
{
        blkdev_issue_flush(buftarg->bt_bdev, GFP_KERNEL, NULL);
}

STATIC void
xfs_close_devices(
        struct xfs_mount        *mp)
{
        if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp) {
                struct block_device *logdev = mp->m_logdev_targp->bt_bdev;
                xfs_free_buftarg(mp, mp->m_logdev_targp);
                xfs_blkdev_put(logdev);
        }
        if (mp->m_rtdev_targp) {
                struct block_device *rtdev = mp->m_rtdev_targp->bt_bdev;
                xfs_free_buftarg(mp, mp->m_rtdev_targp);
                xfs_blkdev_put(rtdev);
        }
        xfs_free_buftarg(mp, mp->m_ddev_targp);
}

/*
 * 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 sb->s_bdev.
 */
STATIC int
xfs_open_devices(
        struct xfs_mount        *mp)
{
        struct block_device     *ddev = mp->m_super->s_bdev;
        struct block_device     *logdev = NULL, *rtdev = NULL;
        int                     error;

        /*
         * Open real time and log devices - order is important.
         */
        if (mp->m_logname) {
                error = xfs_blkdev_get(mp, mp->m_logname, &logdev);
                if (error)
                        goto out;
        }

        if (mp->m_rtname) {
                error = xfs_blkdev_get(mp, mp->m_rtname, &rtdev);
                if (error)
                        goto out_close_logdev;

                if (rtdev == ddev || rtdev == logdev) {
                        xfs_warn(mp,
        "Cannot mount filesystem with identical rtdev and ddev/logdev.");
                        error = EINVAL;
                        goto out_close_rtdev;
                }
        }

        /*
         * Setup xfs_mount buffer target pointers
         */
        error = ENOMEM;
        mp->m_ddev_targp = xfs_alloc_buftarg(mp, ddev, 0, mp->m_fsname);
        if (!mp->m_ddev_targp)
                goto out_close_rtdev;

        if (rtdev) {
                mp->m_rtdev_targp = xfs_alloc_buftarg(mp, rtdev, 1,
                                                        mp->m_fsname);
                if (!mp->m_rtdev_targp)
                        goto out_free_ddev_targ;
        }

        if (logdev && logdev != ddev) {
                mp->m_logdev_targp = xfs_alloc_buftarg(mp, logdev, 1,
                                                        mp->m_fsname);
                if (!mp->m_logdev_targp)
                        goto out_free_rtdev_targ;
        } else {
                mp->m_logdev_targp = mp->m_ddev_targp;
        }

        return 0;

 out_free_rtdev_targ:
        if (mp->m_rtdev_targp)
                xfs_free_buftarg(mp, mp->m_rtdev_targp);
 out_free_ddev_targ:
        xfs_free_buftarg(mp, mp->m_ddev_targp);
 out_close_rtdev:
        if (rtdev)
                xfs_blkdev_put(rtdev);
 out_close_logdev:
        if (logdev && logdev != ddev)
                xfs_blkdev_put(logdev);
 out:
        return error;
}

/*
 * Setup xfs_mount buffer target pointers based on superblock
 */
STATIC int
xfs_setup_devices(
        struct xfs_mount        *mp)
{
        int                     error;

        error = xfs_setsize_buftarg(mp->m_ddev_targp, mp->m_sb.sb_blocksize,
                                    mp->m_sb.sb_sectsize);
        if (error)
                return error;

        if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp) {
                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)
                        return error;
        }
        if (mp->m_rtdev_targp) {
                error = xfs_setsize_buftarg(mp->m_rtdev_targp,
                                            mp->m_sb.sb_blocksize,
                                            mp->m_sb.sb_sectsize);
                if (error)
                        return error;
        }

        return 0;
}

/*
 * XFS AIL push thread support
 */
void
xfsaild_wakeup(
        struct xfs_ail          *ailp,
        xfs_lsn_t               threshold_lsn)
{
        /* only ever move the target forwards */
        if (XFS_LSN_CMP(threshold_lsn, ailp->xa_target) > 0) {
                ailp->xa_target = threshold_lsn;
                wake_up_process(ailp->xa_task);
        }
}

STATIC int
xfsaild(
        void    *data)
{
        struct xfs_ail  *ailp = data;
        xfs_lsn_t       last_pushed_lsn = 0;
        long            tout = 0; /* milliseconds */

        while (!kthread_should_stop()) {
                /*
                 * for short sleeps indicating congestion, don't allow us to
                 * get woken early. Otherwise all we do is bang on the AIL lock
                 * without making progress.
                 */
                if (tout && tout <= 20)
                        __set_current_state(TASK_KILLABLE);
                else
                        __set_current_state(TASK_INTERRUPTIBLE);
                schedule_timeout(tout ?
                                 msecs_to_jiffies(tout) : MAX_SCHEDULE_TIMEOUT);

                /* swsusp */
                try_to_freeze();

                ASSERT(ailp->xa_mount->m_log);
                if (XFS_FORCED_SHUTDOWN(ailp->xa_mount))
                        continue;

                tout = xfsaild_push(ailp, &last_pushed_lsn);
        }

        return 0;
}       /* xfsaild */

int
xfsaild_start(
        struct xfs_ail  *ailp)
{
        ailp->xa_target = 0;
        ailp->xa_task = kthread_run(xfsaild, ailp, "xfsaild/%s",
                                    ailp->xa_mount->m_fsname);
        if (IS_ERR(ailp->xa_task))
                return -PTR_ERR(ailp->xa_task);
        return 0;
}

void
xfsaild_stop(
        struct xfs_ail  *ailp)
{
        kthread_stop(ailp->xa_task);
}


/* Catch misguided souls that try to use this interface on XFS */
STATIC struct inode *
xfs_fs_alloc_inode(
        struct super_block      *sb)
{
        BUG();
        return NULL;
}

/*
 * Now that the generic code is guaranteed not to be accessing
 * the linux inode, we can reclaim the inode.
 */
STATIC void
xfs_fs_destroy_inode(
        struct inode            *inode)
{
        struct xfs_inode        *ip = XFS_I(inode);

        trace_xfs_destroy_inode(ip);

        XFS_STATS_INC(vn_reclaim);

        /* bad inode, get out here ASAP */
        if (is_bad_inode(inode))
                goto out_reclaim;

        xfs_ioend_wait(ip);

        ASSERT(XFS_FORCED_SHUTDOWN(ip->i_mount) || ip->i_delayed_blks == 0);

        /*
         * We should never get here with one of the reclaim flags already set.
         */
        ASSERT_ALWAYS(!xfs_iflags_test(ip, XFS_IRECLAIMABLE));
        ASSERT_ALWAYS(!xfs_iflags_test(ip, XFS_IRECLAIM));

        /*
         * We always use background reclaim here because even if the
         * inode is clean, it still may be under IO and hence we have
         * to take the flush lock. The background reclaim path handles
         * this more efficiently than we can here, so simply let background
         * reclaim tear down all inodes.
         */
out_reclaim:
        xfs_inode_set_reclaim_tag(ip);
}

/*
 * Slab object creation initialisation for the XFS inode.
 * This covers only the idempotent fields in the XFS inode;
 * all other fields need to be initialised on allocation
 * from the slab. This avoids the need to repeatedly initialise
 * fields in the xfs inode that left in the initialise state
 * when freeing the inode.
 */
STATIC void
xfs_fs_inode_init_once(
        void                    *inode)
{
        struct xfs_inode        *ip = inode;

        memset(ip, 0, sizeof(struct xfs_inode));

        /* vfs inode */
        inode_init_once(VFS_I(ip));

        /* xfs inode */
        atomic_set(&ip->i_iocount, 0);
        atomic_set(&ip->i_pincount, 0);
        spin_lock_init(&ip->i_flags_lock);
        init_waitqueue_head(&ip->i_ipin_wait);
        /*
         * Because we want to use a counting completion, complete
         * the flush completion once to allow a single access to
         * the flush completion without blocking.
         */
        init_completion(&ip->i_flush);
        complete(&ip->i_flush);

        mrlock_init(&ip->i_lock, MRLOCK_ALLOW_EQUAL_PRI|MRLOCK_BARRIER,
                     "xfsino", ip->i_ino);
}

/*
 * Dirty the XFS inode when mark_inode_dirty_sync() is called so that
 * we catch unlogged VFS level updates to the inode.
 *
 * We need the barrier() to maintain correct ordering between unlogged
 * updates and the transaction commit code that clears the i_update_core
 * field. This requires all updates to be completed before marking the
 * inode dirty.
 */
STATIC void
xfs_fs_dirty_inode(
        struct inode    *inode)
{
        barrier();
        XFS_I(inode)->i_update_core = 1;
}

STATIC int
xfs_log_inode(
        struct xfs_inode        *ip)
{
        struct xfs_mount        *mp = ip->i_mount;
        struct xfs_trans        *tp;
        int                     error;

        xfs_iunlock(ip, XFS_ILOCK_SHARED);
        tp = xfs_trans_alloc(mp, XFS_TRANS_FSYNC_TS);
        error = xfs_trans_reserve(tp, 0, XFS_FSYNC_TS_LOG_RES(mp), 0, 0, 0);

        if (error) {
                xfs_trans_cancel(tp, 0);
                /* we need to return with the lock hold shared */
                xfs_ilock(ip, XFS_ILOCK_SHARED);
                return error;
        }

        xfs_ilock(ip, XFS_ILOCK_EXCL);

        /*
         * Note - it's possible that we might have pushed ourselves out of the
         * way during trans_reserve which would flush the inode.  But there's
         * no guarantee that the inode buffer has actually gone out yet (it's
         * delwri).  Plus the buffer could be pinned anyway if it's part of
         * an inode in another recent transaction.  So we play it safe and
         * fire off the transaction anyway.
         */
        xfs_trans_ijoin(tp, ip);
        xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
        error = xfs_trans_commit(tp, 0);
        xfs_ilock_demote(ip, XFS_ILOCK_EXCL);

        return error;
}

STATIC int
xfs_fs_write_inode(
        struct inode            *inode,
        struct writeback_control *wbc)
{
        struct xfs_inode        *ip = XFS_I(inode);
        struct xfs_mount        *mp = ip->i_mount;
        int                     error = EAGAIN;

        trace_xfs_write_inode(ip);

        if (XFS_FORCED_SHUTDOWN(mp))
                return XFS_ERROR(EIO);

        if (wbc->sync_mode == WB_SYNC_ALL) {
                /*
                 * Make sure the inode has made it it into the log.  Instead
                 * of forcing it all the way to stable storage using a
                 * synchronous transaction we let the log force inside the
                 * ->sync_fs call do that for thus, which reduces the number
                 * of synchronous log foces dramatically.
                 */
                xfs_ioend_wait(ip);
                xfs_ilock(ip, XFS_ILOCK_SHARED);
                if (ip->i_update_core) {
                        error = xfs_log_inode(ip);
                        if (error)
                                goto out_unlock;
                }
        } else {
                /*
                 * We make this non-blocking if the inode is contended, return
                 * EAGAIN to indicate to the caller that they did not succeed.
                 * This prevents the flush path from blocking on inodes inside
                 * another operation right now, they get caught later by
                 * xfs_sync.
                 */
                if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED))
                        goto out;

                if (xfs_ipincount(ip) || !xfs_iflock_nowait(ip))
                        goto out_unlock;

                /*
                 * Now we have the flush lock and the inode is not pinned, we
                 * can check if the inode is really clean as we know that
                 * there are no pending transaction completions, it is not
                 * waiting on the delayed write queue and there is no IO in
                 * progress.
                 */
                if (xfs_inode_clean(ip)) {
                        xfs_ifunlock(ip);
                        error = 0;
                        goto out_unlock;
                }
                error = xfs_iflush(ip, SYNC_TRYLOCK);
        }

 out_unlock:
        xfs_iunlock(ip, XFS_ILOCK_SHARED);
 out:
        /*
         * if we failed to write out the inode then mark
         * it dirty again so we'll try again later.
         */
        if (error)
                xfs_mark_inode_dirty_sync(ip);
        return -error;
}

STATIC void
xfs_fs_evict_inode(
        struct inode            *inode)
{
        xfs_inode_t             *ip = XFS_I(inode);

        trace_xfs_evict_inode(ip);

        truncate_inode_pages(&inode->i_data, 0);
        end_writeback(inode);
        XFS_STATS_INC(vn_rele);
        XFS_STATS_INC(vn_remove);
        XFS_STATS_DEC(vn_active);

        /*
         * The iolock is used by the file system to coordinate reads,
         * writes, and block truncates.  Up to this point the lock
         * protected concurrent accesses by users of the inode.  But
         * from here forward we're doing some final processing of the
         * inode because we're done with it, and although we reuse the
         * iolock for protection it is really a distinct lock class
         * (in the lockdep sense) from before.  To keep lockdep happy
         * (and basically indicate what we are doing), we explicitly
         * re-init the iolock here.
         */
        ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock));
        mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
        lockdep_set_class_and_name(&ip->i_iolock.mr_lock,
                        &xfs_iolock_reclaimable, "xfs_iolock_reclaimable");

        xfs_inactive(ip);
}

STATIC void
xfs_free_fsname(
        struct xfs_mount        *mp)
{
        kfree(mp->m_fsname);
        kfree(mp->m_rtname);
        kfree(mp->m_logname);
}

STATIC void
xfs_fs_put_super(
        struct super_block      *sb)
{
        struct xfs_mount        *mp = XFS_M(sb);

        /*
         * Unregister the memory shrinker before we tear down the mount
         * structure so we don't have memory reclaim racing with us here.
         */
        xfs_inode_shrinker_unregister(mp);
        xfs_syncd_stop(mp);

        /*
         * 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);

        xfs_unmountfs(mp);
        xfs_freesb(mp);
        xfs_icsb_destroy_counters(mp);
        xfs_close_devices(mp);
        xfs_free_fsname(mp);
        kfree(mp);
}

STATIC int
xfs_fs_sync_fs(
        struct super_block      *sb,
        int                     wait)
{
        struct xfs_mount        *mp = XFS_M(sb);
        int                     error;

        /*
         * Not much we can do for the first async pass.  Writing out the
         * superblock would be counter-productive as we are going to redirty
         * when writing out other data and metadata (and writing out a single
         * block is quite fast anyway).
         *
         * Try to asynchronously kick off quota syncing at least.
         */
        if (!wait) {
                xfs_qm_sync(mp, SYNC_TRYLOCK);
                return 0;
        }

        error = xfs_quiesce_data(mp);
        if (error)
                return -error;

        if (laptop_mode) {
                /*
                 * The disk must be active because we're syncing.
                 * We schedule xfssyncd now (now that the disk is
                 * active) instead of later (when it might not be).
                 */
                flush_delayed_work_sync(&mp->m_sync_work);
        }

        return 0;
}

STATIC int
xfs_fs_statfs(
        struct dentry           *dentry,
        struct kstatfs          *statp)
{
        struct xfs_mount        *mp = XFS_M(dentry->d_sb);
        xfs_sb_t                *sbp = &mp->m_sb;
        struct xfs_inode        *ip = XFS_I(dentry->d_inode);
        __uint64_t              fakeinos, id;
        xfs_extlen_t            lsize;
        __int64_t               ffree;

        statp->f_type = XFS_SB_MAGIC;
        statp->f_namelen = MAXNAMELEN - 1;

        id = huge_encode_dev(mp->m_ddev_targp->bt_dev);
        statp->f_fsid.val[0] = (u32)id;
        statp->f_fsid.val[1] = (u32)(id >> 32);

        xfs_icsb_sync_counters(mp, XFS_ICSB_LAZY_COUNT);

        spin_lock(&mp->m_sb_lock);
        statp->f_bsize = sbp->sb_blocksize;
        lsize = sbp->sb_logstart ? sbp->sb_logblocks : 0;
        statp->f_blocks = sbp->sb_dblocks - lsize;
        statp->f_bfree = statp->f_bavail =
                                sbp->sb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
        fakeinos = statp->f_bfree << sbp->sb_inopblog;
        statp->f_files =
            MIN(sbp->sb_icount + fakeinos, (__uint64_t)XFS_MAXINUMBER);
        if (mp->m_maxicount)
                statp->f_files = min_t(typeof(statp->f_files),
                                        statp->f_files,
                                        mp->m_maxicount);

        /* make sure statp->f_ffree does not underflow */
        ffree = statp->f_files - (sbp->sb_icount - sbp->sb_ifree);
        statp->f_ffree = max_t(__int64_t, ffree, 0);

        spin_unlock(&mp->m_sb_lock);

        if ((ip->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) ||
            ((mp->m_qflags & (XFS_PQUOTA_ACCT|XFS_OQUOTA_ENFD))) ==
                              (XFS_PQUOTA_ACCT|XFS_OQUOTA_ENFD))
                xfs_qm_statvfs(ip, statp);
        return 0;
}

STATIC void
xfs_save_resvblks(struct xfs_mount *mp)
{
        __uint64_t resblks = 0;

        mp->m_resblks_save = mp->m_resblks;
        xfs_reserve_blocks(mp, &resblks, NULL);
}

STATIC void
xfs_restore_resvblks(struct xfs_mount *mp)
{
        __uint64_t resblks;

        if (mp->m_resblks_save) {
                resblks = mp->m_resblks_save;
                mp->m_resblks_save = 0;
        } else
                resblks = xfs_default_resblks(mp);

        xfs_reserve_blocks(mp, &resblks, NULL);
}

STATIC int
xfs_fs_remount(
        struct super_block      *sb,
        int                     *flags,
        char                    *options)
{
        struct xfs_mount        *mp = XFS_M(sb);
        substring_t             args[MAX_OPT_ARGS];
        char                    *p;
        int                     error;

        while ((p = strsep(&options, ",")) != NULL) {
                int token;

                if (!*p)
                        continue;

                token = match_token(p, tokens, args);
                switch (token) {
                case Opt_barrier:
                        mp->m_flags |= XFS_MOUNT_BARRIER;

                        /*
                         * Test if barriers are actually working if we can,
                         * else delay this check until the filesystem is
                         * marked writeable.
                         */
                        if (!(mp->m_flags & XFS_MOUNT_RDONLY))
                                xfs_mountfs_check_barriers(mp);
                        break;
                case Opt_nobarrier:
                        mp->m_flags &= ~XFS_MOUNT_BARRIER;
                        break;
                default:
                        /*
                         * Logically we would return an error here to prevent
                         * users from believing they might have changed
                         * mount options using remount which can't be changed.
                         *
                         * But unfortunately mount(8) adds all options from
                         * mtab and fstab to the mount arguments in some cases
                         * so we can't blindly reject options, but have to
                         * check for each specified option if it actually
                         * differs from the currently set option and only
                         * reject it if that's the case.
                         *
                         * Until that is implemented we return success for
                         * every remount request, and silently ignore all
                         * options that we can't actually change.
                         */
#if 0
                        xfs_info(mp,
                "mount option \"%s\" not supported for remount\n", p);
                        return -EINVAL;
#else
                        break;
#endif
                }
        }

        /* ro -> rw */
        if ((mp->m_flags & XFS_MOUNT_RDONLY) && !(*flags & MS_RDONLY)) {
                mp->m_flags &= ~XFS_MOUNT_RDONLY;
                if (mp->m_flags & XFS_MOUNT_BARRIER)
                        xfs_mountfs_check_barriers(mp);

                /*
                 * If this is the first remount to writeable state we
                 * might have some superblock changes to update.
                 */
                if (mp->m_update_flags) {
                        error = xfs_mount_log_sb(mp, mp->m_update_flags);
                        if (error) {
                                xfs_warn(mp, "failed to write sb changes");
                                return error;
                        }
                        mp->m_update_flags = 0;
                }

                /*
                 * Fill out the reserve pool if it is empty. Use the stashed
                 * value if it is non-zero, otherwise go with the default.
                 */
                xfs_restore_resvblks(mp);
        }

        /* rw -> ro */
        if (!(mp->m_flags & XFS_MOUNT_RDONLY) && (*flags & MS_RDONLY)) {
                /*
                 * After we have synced the data but before we sync the
                 * metadata, we need to free up the reserve block pool so that
                 * the used block count in the superblock on disk is correct at
                 * the end of the remount. Stash the current reserve pool size
                 * so that if we get remounted rw, we can return it to the same
                 * size.
                 */

                xfs_quiesce_data(mp);
                xfs_save_resvblks(mp);
                xfs_quiesce_attr(mp);
                mp->m_flags |= XFS_MOUNT_RDONLY;
        }

        return 0;
}

/*
 * Second stage of a freeze. The data is already frozen so we only
 * need to take care of the metadata. Once that's done write a dummy
 * record to dirty the log in case of a crash while frozen.
 */
STATIC int
xfs_fs_freeze(
        struct super_block      *sb)
{
        struct xfs_mount        *mp = XFS_M(sb);

        xfs_save_resvblks(mp);
        xfs_quiesce_attr(mp);
        return -xfs_fs_log_dummy(mp);
}

STATIC int
xfs_fs_unfreeze(
        struct super_block      *sb)
{
        struct xfs_mount        *mp = XFS_M(sb);

        xfs_restore_resvblks(mp);
        return 0;
}

STATIC int
xfs_fs_show_options(
        struct seq_file         *m,
        struct vfsmount         *mnt)
{
        return -xfs_showargs(XFS_M(mnt->mnt_sb), m);
}

/*
 * 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        *mp)
{
        int                     ronly = (mp->m_flags & XFS_MOUNT_RDONLY);

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

        /*
         * mkfs'ed attr2 will turn on attr2 mount unless explicitly
         * told by noattr2 to turn it off
         */
        if (xfs_sb_version_hasattr2(&mp->m_sb) &&
            !(mp->m_flags & XFS_MOUNT_NOATTR2))
                mp->m_flags |= XFS_MOUNT_ATTR2;

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

        return 0;
}

STATIC int
xfs_fs_fill_super(
        struct super_block      *sb,
        void                    *data,
        int                     silent)
{
        struct inode            *root;
        struct xfs_mount        *mp = NULL;
        int                     flags = 0, error = ENOMEM;

        mp = kzalloc(sizeof(struct xfs_mount), GFP_KERNEL);
        if (!mp)
                goto out;

        spin_lock_init(&mp->m_sb_lock);
        mutex_init(&mp->m_growlock);
        atomic_set(&mp->m_active_trans, 0);
        INIT_LIST_HEAD(&mp->m_sync_list);
        spin_lock_init(&mp->m_sync_lock);

        mp->m_super = sb;
        sb->s_fs_info = mp;

        error = xfs_parseargs(mp, (char *)data);
        if (error)
                goto out_free_fsname;

        sb_min_blocksize(sb, BBSIZE);
        sb->s_xattr = xfs_xattr_handlers;
        sb->s_export_op = &xfs_export_operations;
#ifdef CONFIG_XFS_QUOTA
        sb->s_qcop = &xfs_quotactl_operations;
#endif
        sb->s_op = &xfs_super_operations;

        if (silent)
                flags |= XFS_MFSI_QUIET;

        error = xfs_open_devices(mp);
        if (error)
                goto out_free_fsname;

        error = xfs_icsb_init_counters(mp);
        if (error)
                goto out_close_devices;

        error = xfs_readsb(mp, flags);
        if (error)
                goto out_destroy_counters;

        error = xfs_finish_flags(mp);
        if (error)
                goto out_free_sb;

        error = xfs_setup_devices(mp);
        if (error)
                goto out_free_sb;

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

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

        /*
         * we must configure the block size in the superblock before we run the
         * full mount process as the mount process can lookup and cache inodes.
         * For the same reason we must also initialise the syncd and register
         * the inode cache shrinker so that inodes can be reclaimed during
         * operations like a quotacheck that iterate all inodes in the
         * filesystem.
         */
        sb->s_magic = XFS_SB_MAGIC;
        sb->s_blocksize = mp->m_sb.sb_blocksize;
        sb->s_blocksize_bits = ffs(sb->s_blocksize) - 1;
        sb->s_maxbytes = xfs_max_file_offset(sb->s_blocksize_bits);
        sb->s_time_gran = 1;
        set_posix_acl_flag(sb);

        error = xfs_syncd_init(mp);
        if (error)
                goto out_filestream_unmount;

        xfs_inode_shrinker_register(mp);

        error = xfs_mountfs(mp);
        if (error)
                goto out_syncd_stop;

        root = igrab(VFS_I(mp->m_rootip));
        if (!root) {
                error = ENOENT;
                goto fail_unmount;
        }
        if (is_bad_inode(root)) {
                error = EINVAL;
                goto fail_vnrele;
        }
        sb->s_root = d_alloc_root(root);
        if (!sb->s_root) {
                error = ENOMEM;
                goto fail_vnrele;
        }

        return 0;

 out_syncd_stop:
        xfs_inode_shrinker_unregister(mp);
        xfs_syncd_stop(mp);
 out_filestream_unmount:
        xfs_filestream_unmount(mp);
 out_free_sb:
        xfs_freesb(mp);
 out_destroy_counters:
        xfs_icsb_destroy_counters(mp);
 out_close_devices:
        xfs_close_devices(mp);
 out_free_fsname:
        xfs_free_fsname(mp);
        kfree(mp);
 out:
        return -error;

 fail_vnrele:
        if (sb->s_root) {
                dput(sb->s_root);
                sb->s_root = NULL;
        } else {
                iput(root);
        }

 fail_unmount:
        xfs_inode_shrinker_unregister(mp);
        xfs_syncd_stop(mp);

        /*
         * 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);

        xfs_unmountfs(mp);
        goto out_free_sb;
}

STATIC struct dentry *
xfs_fs_mount(
        struct file_system_type *fs_type,
        int                     flags,
        const char              *dev_name,
        void                    *data)
{
        return mount_bdev(fs_type, flags, dev_name, data, xfs_fs_fill_super);
}

static const struct super_operations xfs_super_operations = {
        .alloc_inode            = xfs_fs_alloc_inode,
        .destroy_inode          = xfs_fs_destroy_inode,
        .dirty_inode            = xfs_fs_dirty_inode,
        .write_inode            = xfs_fs_write_inode,
        .evict_inode            = xfs_fs_evict_inode,
        .put_super              = xfs_fs_put_super,
        .sync_fs                = xfs_fs_sync_fs,
        .freeze_fs              = xfs_fs_freeze,
        .unfreeze_fs            = xfs_fs_unfreeze,
        .statfs                 = xfs_fs_statfs,
        .remount_fs             = xfs_fs_remount,
        .show_options           = xfs_fs_show_options,
};

static struct file_system_type xfs_fs_type = {
        .owner                  = THIS_MODULE,
        .name                   = "xfs",
        .mount                  = xfs_fs_mount,
        .kill_sb                = kill_block_super,
        .fs_flags               = FS_REQUIRES_DEV,
};

STATIC int __init
xfs_init_zones(void)
{

        xfs_ioend_zone = kmem_zone_init(sizeof(xfs_ioend_t), "xfs_ioend");
        if (!xfs_ioend_zone)
                goto out;

        xfs_ioend_pool = mempool_create_slab_pool(4 * MAX_BUF_PER_PAGE,
                                                  xfs_ioend_zone);
        if (!xfs_ioend_pool)
                goto out_destroy_ioend_zone;

        xfs_log_ticket_zone = kmem_zone_init(sizeof(xlog_ticket_t),
                                                "xfs_log_ticket");
        if (!xfs_log_ticket_zone)
                goto out_destroy_ioend_pool;

        xfs_bmap_free_item_zone = kmem_zone_init(sizeof(xfs_bmap_free_item_t),
                                                "xfs_bmap_free_item");
        if (!xfs_bmap_free_item_zone)
                goto out_destroy_log_ticket_zone;

        xfs_btree_cur_zone = kmem_zone_init(sizeof(xfs_btree_cur_t),
                                                "xfs_btree_cur");
        if (!xfs_btree_cur_zone)
                goto out_destroy_bmap_free_item_zone;

        xfs_da_state_zone = kmem_zone_init(sizeof(xfs_da_state_t),
                                                "xfs_da_state");
        if (!xfs_da_state_zone)
                goto out_destroy_btree_cur_zone;

        xfs_dabuf_zone = kmem_zone_init(sizeof(xfs_dabuf_t), "xfs_dabuf");
        if (!xfs_dabuf_zone)
                goto out_destroy_da_state_zone;

        xfs_ifork_zone = kmem_zone_init(sizeof(xfs_ifork_t), "xfs_ifork");
        if (!xfs_ifork_zone)
                goto out_destroy_dabuf_zone;

        xfs_trans_zone = kmem_zone_init(sizeof(xfs_trans_t), "xfs_trans");
        if (!xfs_trans_zone)
                goto out_destroy_ifork_zone;

        xfs_log_item_desc_zone =
                kmem_zone_init(sizeof(struct xfs_log_item_desc),
                               "xfs_log_item_desc");
        if (!xfs_log_item_desc_zone)
                goto out_destroy_trans_zone;

        /*
         * 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_BLF_CHUNK) /
                                  NBWORD) * sizeof(int))), "xfs_buf_item");
        if (!xfs_buf_item_zone)
                goto out_destroy_log_item_desc_zone;

        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");
        if (!xfs_efd_zone)
                goto out_destroy_buf_item_zone;

        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");
        if (!xfs_efi_zone)
                goto out_destroy_efd_zone;

        xfs_inode_zone =
                kmem_zone_init_flags(sizeof(xfs_inode_t), "xfs_inode",
                        KM_ZONE_HWALIGN | KM_ZONE_RECLAIM | KM_ZONE_SPREAD,
                        xfs_fs_inode_init_once);
        if (!xfs_inode_zone)
                goto out_destroy_efi_zone;

        xfs_ili_zone =
                kmem_zone_init_flags(sizeof(xfs_inode_log_item_t), "xfs_ili",
                                        KM_ZONE_SPREAD, NULL);
        if (!xfs_ili_zone)
                goto out_destroy_inode_zone;

        return 0;

 out_destroy_inode_zone:
        kmem_zone_destroy(xfs_inode_zone);
 out_destroy_efi_zone:
        kmem_zone_destroy(xfs_efi_zone);
 out_destroy_efd_zone:
        kmem_zone_destroy(xfs_efd_zone);
 out_destroy_buf_item_zone:
        kmem_zone_destroy(xfs_buf_item_zone);
 out_destroy_log_item_desc_zone:
        kmem_zone_destroy(xfs_log_item_desc_zone);
 out_destroy_trans_zone:
        kmem_zone_destroy(xfs_trans_zone);
 out_destroy_ifork_zone:
        kmem_zone_destroy(xfs_ifork_zone);
 out_destroy_dabuf_zone:
        kmem_zone_destroy(xfs_dabuf_zone);
 out_destroy_da_state_zone:
        kmem_zone_destroy(xfs_da_state_zone);
 out_destroy_btree_cur_zone:
        kmem_zone_destroy(xfs_btree_cur_zone);
 out_destroy_bmap_free_item_zone:
        kmem_zone_destroy(xfs_bmap_free_item_zone);
 out_destroy_log_ticket_zone:
        kmem_zone_destroy(xfs_log_ticket_zone);
 out_destroy_ioend_pool:
        mempool_destroy(xfs_ioend_pool);
 out_destroy_ioend_zone:
        kmem_zone_destroy(xfs_ioend_zone);
 out:
        return -ENOMEM;
}

STATIC void
xfs_destroy_zones(void)
{
        kmem_zone_destroy(xfs_ili_zone);
        kmem_zone_destroy(xfs_inode_zone);
        kmem_zone_destroy(xfs_efi_zone);
        kmem_zone_destroy(xfs_efd_zone);
        kmem_zone_destroy(xfs_buf_item_zone);
        kmem_zone_destroy(xfs_log_item_desc_zone);
        kmem_zone_destroy(xfs_trans_zone);
        kmem_zone_destroy(xfs_ifork_zone);
        kmem_zone_destroy(xfs_dabuf_zone);
        kmem_zone_destroy(xfs_da_state_zone);
        kmem_zone_destroy(xfs_btree_cur_zone);
        kmem_zone_destroy(xfs_bmap_free_item_zone);
        kmem_zone_destroy(xfs_log_ticket_zone);
        mempool_destroy(xfs_ioend_pool);
        kmem_zone_destroy(xfs_ioend_zone);

}

STATIC int __init
init_xfs_fs(void)
{
        int                     error;

        printk(KERN_INFO XFS_VERSION_STRING " with "
                         XFS_BUILD_OPTIONS " enabled\n");

        xfs_ioend_init();
        xfs_dir_startup();

        error = xfs_init_zones();
        if (error)
                goto out;

        error = xfs_mru_cache_init();
        if (error)
                goto out_destroy_zones;

        error = xfs_filestream_init();
        if (error)
                goto out_mru_cache_uninit;

        error = xfs_buf_init();
        if (error)
                goto out_filestream_uninit;

        error = xfs_init_procfs();
        if (error)
                goto out_buf_terminate;

        error = xfs_sysctl_register();
        if (error)
                goto out_cleanup_procfs;

        /*
         * max_active is set to 8 to give enough concurency to allow
         * multiple work operations on each CPU to run. This allows multiple
         * filesystems to be running sync work concurrently, and scales with
         * the number of CPUs in the system.
         */
        xfs_syncd_wq = alloc_workqueue("xfssyncd", WQ_CPU_INTENSIVE, 8);
        if (!xfs_syncd_wq) {
                error = -ENOMEM;
                goto out_sysctl_unregister;
        }

        vfs_initquota();

        error = register_filesystem(&xfs_fs_type);
        if (error)
                goto out_destroy_xfs_syncd;
        return 0;

 out_destroy_xfs_syncd:
        destroy_workqueue(xfs_syncd_wq);
 out_sysctl_unregister:
        xfs_sysctl_unregister();
 out_cleanup_procfs:
        xfs_cleanup_procfs();
 out_buf_terminate:
        xfs_buf_terminate();
 out_filestream_uninit:
        xfs_filestream_uninit();
 out_mru_cache_uninit:
        xfs_mru_cache_uninit();
 out_destroy_zones:
        xfs_destroy_zones();
 out:
        return error;
}

STATIC void __exit
exit_xfs_fs(void)
{
        vfs_exitquota();
        unregister_filesystem(&xfs_fs_type);
        destroy_workqueue(xfs_syncd_wq);
        xfs_sysctl_unregister();
        xfs_cleanup_procfs();
        xfs_buf_terminate();
        xfs_filestream_uninit();
        xfs_mru_cache_uninit();
        xfs_destroy_zones();
}

module_init(init_xfs_fs);
module_exit(exit_xfs_fs);

MODULE_AUTHOR("Silicon Graphics, Inc.");
MODULE_DESCRIPTION(XFS_VERSION_STRING " with " XFS_BUILD_OPTIONS " enabled");
MODULE_LICENSE("GPL");