/*
 * 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_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_sb.h"
#include "xfs_mount.h"
#include "xfs_da_format.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_bmap.h"
#include "xfs_alloc.h"
#include "xfs_error.h"
#include "xfs_fsops.h"
#include "xfs_trans.h"
#include "xfs_buf_item.h"
#include "xfs_log.h"
#include "xfs_log_priv.h"
#include "xfs_da_btree.h"
#include "xfs_dir2.h"
#include "xfs_extfree_item.h"
#include "xfs_mru_cache.h"
#include "xfs_inode_item.h"
#include "xfs_icache.h"
#include "xfs_trace.h"
#include "xfs_icreate_item.h"
#include "xfs_filestream.h"
#include "xfs_quota.h"
#include "xfs_sysfs.h"
#include "xfs_ondisk.h"
#include "xfs_rmap_item.h"
#include "xfs_refcount_item.h"
#include "xfs_bmap_item.h"
#include "xfs_reflink.h"

#include <linux/namei.h>
#include <linux/dax.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;
struct bio_set *xfs_ioend_bioset;

static struct kset *xfs_kset;           /* top-level xfs sysfs dir */
#ifdef DEBUG
static struct xfs_kobj xfs_dbg_kobj;    /* global debug sysfs attrs */
#endif

/*
 * Table driven mount option parser.
 */
enum {
        Opt_logbufs, Opt_logbsize, Opt_logdev, Opt_rtdev, Opt_biosize,
        Opt_wsync, Opt_noalign, Opt_swalloc, Opt_sunit, Opt_swidth, Opt_nouuid,
        Opt_mtpt, Opt_grpid, Opt_nogrpid, Opt_bsdgroups, Opt_sysvgroups,
        Opt_allocsize, Opt_norecovery, Opt_barrier, Opt_nobarrier,
        Opt_inode64, Opt_inode32, Opt_ikeep, Opt_noikeep,
        Opt_largeio, Opt_nolargeio, Opt_attr2, Opt_noattr2, Opt_filestreams,
        Opt_quota, Opt_noquota, Opt_usrquota, Opt_grpquota, Opt_prjquota,
        Opt_uquota, Opt_gquota, Opt_pquota,
        Opt_uqnoenforce, Opt_gqnoenforce, Opt_pqnoenforce, Opt_qnoenforce,
        Opt_discard, Opt_nodiscard, Opt_dax, Opt_err,
};

static const match_table_t tokens = {
        {Opt_logbufs,   "logbufs=%u"},  /* number of XFS log buffers */
        {Opt_logbsize,  "logbsize=%s"}, /* size of XFS log buffers */
        {Opt_logdev,    "logdev=%s"},   /* log device */
        {Opt_rtdev,     "rtdev=%s"},    /* realtime I/O device */
        {Opt_biosize,   "biosize=%u"},  /* log2 of preferred buffered io size */
        {Opt_wsync,     "wsync"},       /* safe-mode nfs compatible mount */
        {Opt_noalign,   "noalign"},     /* turn off stripe alignment */
        {Opt_swalloc,   "swalloc"},     /* turn on stripe width allocation */
        {Opt_sunit,     "sunit=%u"},    /* data volume stripe unit */
        {Opt_swidth,    "swidth=%u"},   /* data volume stripe width */
        {Opt_nouuid,    "nouuid"},      /* ignore filesystem UUID */
        {Opt_mtpt,      "mtpt"},        /* filesystem mount point */
        {Opt_grpid,     "grpid"},       /* group-ID from parent directory */
        {Opt_nogrpid,   "nogrpid"},     /* group-ID from current process */
        {Opt_bsdgroups, "bsdgroups"},   /* group-ID from parent directory */
        {Opt_sysvgroups,"sysvgroups"},  /* group-ID from current process */
        {Opt_allocsize, "allocsize=%s"},/* preferred allocation size */
        {Opt_norecovery,"norecovery"},  /* don't run XFS recovery */
        {Opt_inode64,   "inode64"},     /* inodes can be allocated anywhere */
        {Opt_inode32,   "inode32"},     /* inode allocation limited to
                                         * XFS_MAXINUMBER_32 */
        {Opt_ikeep,     "ikeep"},       /* do not free empty inode clusters */
        {Opt_noikeep,   "noikeep"},     /* free empty inode clusters */
        {Opt_largeio,   "largeio"},     /* report large I/O sizes in stat() */
        {Opt_nolargeio, "nolargeio"},   /* do not report large I/O sizes
                                         * in stat(). */
        {Opt_attr2,     "attr2"},       /* do use attr2 attribute format */
        {Opt_noattr2,   "noattr2"},     /* do not use attr2 attribute format */
        {Opt_filestreams,"filestreams"},/* use filestreams allocator */
        {Opt_quota,     "quota"},       /* disk quotas (user) */
        {Opt_noquota,   "noquota"},     /* no quotas */
        {Opt_usrquota,  "usrquota"},    /* user quota enabled */
        {Opt_grpquota,  "grpquota"},    /* group quota enabled */
        {Opt_prjquota,  "prjquota"},    /* project quota enabled */
        {Opt_uquota,    "uquota"},      /* user quota (IRIX variant) */
        {Opt_gquota,    "gquota"},      /* group quota (IRIX variant) */
        {Opt_pquota,    "pquota"},      /* project quota (IRIX variant) */
        {Opt_uqnoenforce,"uqnoenforce"},/* user quota limit enforcement */
        {Opt_gqnoenforce,"gqnoenforce"},/* group quota limit enforcement */
        {Opt_pqnoenforce,"pqnoenforce"},/* project quota limit enforcement */
        {Opt_qnoenforce, "qnoenforce"}, /* same as uqnoenforce */
        {Opt_discard,   "discard"},     /* Discard unused blocks */
        {Opt_nodiscard, "nodiscard"},   /* Do not discard unused blocks */

        {Opt_dax,       "dax"},         /* Enable direct access to bdev pages */

        /* Deprecated mount options scheduled for removal */
        {Opt_barrier,   "barrier"},     /* use writer barriers for log write and
                                         * unwritten extent conversion */
        {Opt_nobarrier, "nobarrier"},   /* .. disable */

        {Opt_err,       NULL},
};


STATIC int
suffix_kstrtoint(const substring_t *s, unsigned int base, int *res)
{
        int     last, shift_left_factor = 0, _res;
        char    *value;
        int     ret = 0;

        value = match_strdup(s);
        if (!value)
                return -ENOMEM;

        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';
        }

        if (kstrtoint(value, base, &_res))
                ret = -EINVAL;
        kfree(value);
        *res = _res << shift_left_factor;
        return ret;
}

/*
 * 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.
 *
 * *sb is const because this is also used to test options on the remount
 * path, and we don't want this to have any side effects at remount time.
 * Today this function does not change *sb, but just to future-proof...
 */
STATIC int
xfs_parseargs(
        struct xfs_mount        *mp,
        char                    *options)
{
        const struct super_block *sb = mp->m_super;
        char                    *p;
        substring_t             args[MAX_OPT_ARGS];
        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_rdonly(sb))
                mp->m_flags |= XFS_MOUNT_RDONLY;
        if (sb->s_flags & SB_DIRSYNC)
                mp->m_flags |= XFS_MOUNT_DIRSYNC;
        if (sb->s_flags & SB_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;

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

        if (!options)
                goto done;

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

                if (!*p)
                        continue;

                token = match_token(p, tokens, args);
                switch (token) {
                case Opt_logbufs:
                        if (match_int(args, &mp->m_logbufs))
                                return -EINVAL;
                        break;
                case Opt_logbsize:
                        if (suffix_kstrtoint(args, 10, &mp->m_logbsize))
                                return -EINVAL;
                        break;
                case Opt_logdev:
                        kfree(mp->m_logname);
                        mp->m_logname = match_strdup(args);
                        if (!mp->m_logname)
                                return -ENOMEM;
                        break;
                case Opt_mtpt:
                        xfs_warn(mp, "%s option not allowed on this system", p);
                        return -EINVAL;
                case Opt_rtdev:
                        kfree(mp->m_rtname);
                        mp->m_rtname = match_strdup(args);
                        if (!mp->m_rtname)
                                return -ENOMEM;
                        break;
                case Opt_allocsize:
                case Opt_biosize:
                        if (suffix_kstrtoint(args, 10, &iosize))
                                return -EINVAL;
                        iosizelog = ffs(iosize) - 1;
                        break;
                case Opt_grpid:
                case Opt_bsdgroups:
                        mp->m_flags |= XFS_MOUNT_GRPID;
                        break;
                case Opt_nogrpid:
                case Opt_sysvgroups:
                        mp->m_flags &= ~XFS_MOUNT_GRPID;
                        break;
                case Opt_wsync:
                        mp->m_flags |= XFS_MOUNT_WSYNC;
                        break;
                case Opt_norecovery:
                        mp->m_flags |= XFS_MOUNT_NORECOVERY;
                        break;
                case Opt_noalign:
                        mp->m_flags |= XFS_MOUNT_NOALIGN;
                        break;
                case Opt_swalloc:
                        mp->m_flags |= XFS_MOUNT_SWALLOC;
                        break;
                case Opt_sunit:
                        if (match_int(args, &dsunit))
                                return -EINVAL;
                        break;
                case Opt_swidth:
                        if (match_int(args, &dswidth))
                                return -EINVAL;
                        break;
                case Opt_inode32:
                        mp->m_flags |= XFS_MOUNT_SMALL_INUMS;
                        break;
                case Opt_inode64:
                        mp->m_flags &= ~XFS_MOUNT_SMALL_INUMS;
                        break;
                case Opt_nouuid:
                        mp->m_flags |= XFS_MOUNT_NOUUID;
                        break;
                case Opt_ikeep:
                        mp->m_flags |= XFS_MOUNT_IKEEP;
                        break;
                case Opt_noikeep:
                        mp->m_flags &= ~XFS_MOUNT_IKEEP;
                        break;
                case Opt_largeio:
                        mp->m_flags &= ~XFS_MOUNT_COMPAT_IOSIZE;
                        break;
                case Opt_nolargeio:
                        mp->m_flags |= XFS_MOUNT_COMPAT_IOSIZE;
                        break;
                case Opt_attr2:
                        mp->m_flags |= XFS_MOUNT_ATTR2;
                        break;
                case Opt_noattr2:
                        mp->m_flags &= ~XFS_MOUNT_ATTR2;
                        mp->m_flags |= XFS_MOUNT_NOATTR2;
                        break;
                case Opt_filestreams:
                        mp->m_flags |= XFS_MOUNT_FILESTREAMS;
                        break;
                case Opt_noquota:
                        mp->m_qflags &= ~XFS_ALL_QUOTA_ACCT;
                        mp->m_qflags &= ~XFS_ALL_QUOTA_ENFD;
                        mp->m_qflags &= ~XFS_ALL_QUOTA_ACTIVE;
                        break;
                case Opt_quota:
                case Opt_uquota:
                case Opt_usrquota:
                        mp->m_qflags |= (XFS_UQUOTA_ACCT | XFS_UQUOTA_ACTIVE |
                                         XFS_UQUOTA_ENFD);
                        break;
                case Opt_qnoenforce:
                case Opt_uqnoenforce:
                        mp->m_qflags |= (XFS_UQUOTA_ACCT | XFS_UQUOTA_ACTIVE);
                        mp->m_qflags &= ~XFS_UQUOTA_ENFD;
                        break;
                case Opt_pquota:
                case Opt_prjquota:
                        mp->m_qflags |= (XFS_PQUOTA_ACCT | XFS_PQUOTA_ACTIVE |
                                         XFS_PQUOTA_ENFD);
                        break;
                case Opt_pqnoenforce:
                        mp->m_qflags |= (XFS_PQUOTA_ACCT | XFS_PQUOTA_ACTIVE);
                        mp->m_qflags &= ~XFS_PQUOTA_ENFD;
                        break;
                case Opt_gquota:
                case Opt_grpquota:
                        mp->m_qflags |= (XFS_GQUOTA_ACCT | XFS_GQUOTA_ACTIVE |
                                         XFS_GQUOTA_ENFD);
                        break;
                case Opt_gqnoenforce:
                        mp->m_qflags |= (XFS_GQUOTA_ACCT | XFS_GQUOTA_ACTIVE);
                        mp->m_qflags &= ~XFS_GQUOTA_ENFD;
                        break;
                case Opt_discard:
                        mp->m_flags |= XFS_MOUNT_DISCARD;
                        break;
                case Opt_nodiscard:
                        mp->m_flags &= ~XFS_MOUNT_DISCARD;
                        break;
#ifdef CONFIG_FS_DAX
                case Opt_dax:
                        mp->m_flags |= XFS_MOUNT_DAX;
                        break;
#endif
                case Opt_barrier:
                        xfs_warn(mp, "%s option is deprecated, ignoring.", p);
                        mp->m_flags |= XFS_MOUNT_BARRIER;
                        break;
                case Opt_nobarrier:
                        xfs_warn(mp, "%s option is deprecated, ignoring.", p);
                        mp->m_flags &= ~XFS_MOUNT_BARRIER;
                        break;
                default:
                        xfs_warn(mp, "unknown mount option [%s].", p);
                        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 ((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 (dsunit && !(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.
                 */
                mp->m_dalign = dsunit;
                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 -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 -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 -EINVAL;
                }

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

        return 0;
}

struct proc_xfs_info {
        uint64_t        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,              ",ikeep" },
                { XFS_MOUNT_WSYNC,              ",wsync" },
                { XFS_MOUNT_NOALIGN,            ",noalign" },
                { XFS_MOUNT_SWALLOC,            ",swalloc" },
                { XFS_MOUNT_NOUUID,             ",nouuid" },
                { XFS_MOUNT_NORECOVERY,         ",norecovery" },
                { XFS_MOUNT_ATTR2,              ",attr2" },
                { XFS_MOUNT_FILESTREAMS,        ",filestreams" },
                { XFS_MOUNT_GRPID,              ",grpid" },
                { XFS_MOUNT_DISCARD,            ",discard" },
                { XFS_MOUNT_SMALL_INUMS,        ",inode32" },
                { XFS_MOUNT_DAX,                ",dax" },
                { 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,      ",largeio" },
                { XFS_MOUNT_BARRIER,            ",nobarrier" },
                { XFS_MOUNT_SMALL_INUMS,        ",inode64" },
                { 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, ",allocsize=%dk",
                                (int)(1 << mp->m_writeio_log) >> 10);

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

        if (mp->m_logname)
                seq_show_option(m, "logdev", mp->m_logname);
        if (mp->m_rtname)
                seq_show_option(m, "rtdev", mp->m_rtname);

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

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

        if (mp->m_qflags & XFS_PQUOTA_ACCT) {
                if (mp->m_qflags & XFS_PQUOTA_ENFD)
                        seq_puts(m, ",prjquota");
                else
                        seq_puts(m, ",pqnoenforce");
        }
        if (mp->m_qflags & XFS_GQUOTA_ACCT) {
                if (mp->m_qflags & XFS_GQUOTA_ENFD)
                        seq_puts(m, ",grpquota");
                else
                        seq_puts(m, ",gqnoenforce");
        }

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

        return 0;
}
static 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_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_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_SIZE;
        bitshift = BITS_PER_LONG;
# else
        pagefactor = PAGE_SIZE >> (PAGE_SHIFT - blockshift);
# endif
#endif

        return (((uint64_t)pagefactor) << bitshift) - 1;
}

/*
 * Set parameters for inode allocation heuristics, taking into account
 * filesystem size and inode32/inode64 mount options; i.e. specifically
 * whether or not XFS_MOUNT_SMALL_INUMS is set.
 *
 * Inode allocation patterns are altered only if inode32 is requested
 * (XFS_MOUNT_SMALL_INUMS), and the filesystem is sufficiently large.
 * If altered, XFS_MOUNT_32BITINODES is set as well.
 *
 * An agcount independent of that in the mount structure is provided
 * because in the growfs case, mp->m_sb.sb_agcount is not yet updated
 * to the potentially higher ag count.
 *
 * Returns the maximum AG index which may contain inodes.
 */
xfs_agnumber_t
xfs_set_inode_alloc(
        struct xfs_mount *mp,
        xfs_agnumber_t  agcount)
{
        xfs_agnumber_t  index;
        xfs_agnumber_t  maxagi = 0;
        xfs_sb_t        *sbp = &mp->m_sb;
        xfs_agnumber_t  max_metadata;
        xfs_agino_t     agino;
        xfs_ino_t       ino;

        /*
         * Calculate how much should be reserved for inodes to meet
         * the max inode percentage.  Used only for inode32.
         */
        if (mp->m_maxicount) {
                uint64_t        icount;

                icount = sbp->sb_dblocks * sbp->sb_imax_pct;
                do_div(icount, 100);
                icount += sbp->sb_agblocks - 1;
                do_div(icount, sbp->sb_agblocks);
                max_metadata = icount;
        } else {
                max_metadata = agcount;
        }

        /* Get the last possible inode in the filesystem */
        agino = XFS_OFFBNO_TO_AGINO(mp, sbp->sb_agblocks - 1, 0);
        ino = XFS_AGINO_TO_INO(mp, agcount - 1, agino);

        /*
         * If user asked for no more than 32-bit inodes, and the fs is
         * sufficiently large, set XFS_MOUNT_32BITINODES if we must alter
         * the allocator to accommodate the request.
         */
        if ((mp->m_flags & XFS_MOUNT_SMALL_INUMS) && ino > XFS_MAXINUMBER_32)
                mp->m_flags |= XFS_MOUNT_32BITINODES;
        else
                mp->m_flags &= ~XFS_MOUNT_32BITINODES;

        for (index = 0; index < agcount; index++) {
                struct xfs_perag        *pag;

                ino = XFS_AGINO_TO_INO(mp, index, agino);

                pag = xfs_perag_get(mp, index);

                if (mp->m_flags & XFS_MOUNT_32BITINODES) {
                        if (ino > XFS_MAXINUMBER_32) {
                                pag->pagi_inodeok = 0;
                                pag->pagf_metadata = 0;
                        } else {
                                pag->pagi_inodeok = 1;
                                maxagi++;
                                if (index < max_metadata)
                                        pag->pagf_metadata = 1;
                                else
                                        pag->pagf_metadata = 0;
                        }
                } else {
                        pag->pagi_inodeok = 1;
                        pag->pagf_metadata = 0;
                }

                xfs_perag_put(pag);
        }

        return (mp->m_flags & XFS_MOUNT_32BITINODES) ? maxagi : agcount;
}

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", name, error);
        }

        return error;
}

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

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

STATIC void
xfs_close_devices(
        struct xfs_mount        *mp)
{
        struct dax_device *dax_ddev = mp->m_ddev_targp->bt_daxdev;

        if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp) {
                struct block_device *logdev = mp->m_logdev_targp->bt_bdev;
                struct dax_device *dax_logdev = mp->m_logdev_targp->bt_daxdev;

                xfs_free_buftarg(mp->m_logdev_targp);
                xfs_blkdev_put(logdev);
                fs_put_dax(dax_logdev);
        }
        if (mp->m_rtdev_targp) {
                struct block_device *rtdev = mp->m_rtdev_targp->bt_bdev;
                struct dax_device *dax_rtdev = mp->m_rtdev_targp->bt_daxdev;

                xfs_free_buftarg(mp->m_rtdev_targp);
                xfs_blkdev_put(rtdev);
                fs_put_dax(dax_rtdev);
        }
        xfs_free_buftarg(mp->m_ddev_targp);
        fs_put_dax(dax_ddev);
}

/*
 * 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 dax_device       *dax_ddev = fs_dax_get_by_bdev(ddev);
        struct dax_device       *dax_logdev = NULL, *dax_rtdev = NULL;
        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;
                dax_logdev = fs_dax_get_by_bdev(logdev);
        }

        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;
                }
                dax_rtdev = fs_dax_get_by_bdev(rtdev);
        }

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

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

        if (logdev && logdev != ddev) {
                mp->m_logdev_targp = xfs_alloc_buftarg(mp, logdev, dax_logdev);
                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->m_rtdev_targp);
 out_free_ddev_targ:
        xfs_free_buftarg(mp->m_ddev_targp);
 out_close_rtdev:
        xfs_blkdev_put(rtdev);
        fs_put_dax(dax_rtdev);
 out_close_logdev:
        if (logdev && logdev != ddev) {
                xfs_blkdev_put(logdev);
                fs_put_dax(dax_logdev);
        }
 out:
        fs_put_dax(dax_ddev);
        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_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,
                                            log_sector_size);
                if (error)
                        return error;
        }
        if (mp->m_rtdev_targp) {
                error = xfs_setsize_buftarg(mp->m_rtdev_targp,
                                            mp->m_sb.sb_sectsize);
                if (error)
                        return error;
        }

        return 0;
}

STATIC int
xfs_init_mount_workqueues(
        struct xfs_mount        *mp)
{
        mp->m_buf_workqueue = alloc_workqueue("xfs-buf/%s",
                        WQ_MEM_RECLAIM|WQ_FREEZABLE, 1, mp->m_fsname);
        if (!mp->m_buf_workqueue)
                goto out;

        mp->m_data_workqueue = alloc_workqueue("xfs-data/%s",
                        WQ_MEM_RECLAIM|WQ_FREEZABLE, 0, mp->m_fsname);
        if (!mp->m_data_workqueue)
                goto out_destroy_buf;

        mp->m_unwritten_workqueue = alloc_workqueue("xfs-conv/%s",
                        WQ_MEM_RECLAIM|WQ_FREEZABLE, 0, mp->m_fsname);
        if (!mp->m_unwritten_workqueue)
                goto out_destroy_data_iodone_queue;

        mp->m_cil_workqueue = alloc_workqueue("xfs-cil/%s",
                        WQ_MEM_RECLAIM|WQ_FREEZABLE, 0, mp->m_fsname);
        if (!mp->m_cil_workqueue)
                goto out_destroy_unwritten;

        mp->m_reclaim_workqueue = alloc_workqueue("xfs-reclaim/%s",
                        WQ_MEM_RECLAIM|WQ_FREEZABLE, 0, mp->m_fsname);
        if (!mp->m_reclaim_workqueue)
                goto out_destroy_cil;

        mp->m_log_workqueue = alloc_workqueue("xfs-log/%s",
                        WQ_MEM_RECLAIM|WQ_FREEZABLE|WQ_HIGHPRI, 0,
                        mp->m_fsname);
        if (!mp->m_log_workqueue)
                goto out_destroy_reclaim;

        mp->m_eofblocks_workqueue = alloc_workqueue("xfs-eofblocks/%s",
                        WQ_MEM_RECLAIM|WQ_FREEZABLE, 0, mp->m_fsname);
        if (!mp->m_eofblocks_workqueue)
                goto out_destroy_log;

        mp->m_sync_workqueue = alloc_workqueue("xfs-sync/%s", WQ_FREEZABLE, 0,
                                               mp->m_fsname);
        if (!mp->m_sync_workqueue)
                goto out_destroy_eofb;

        return 0;

out_destroy_eofb:
        destroy_workqueue(mp->m_eofblocks_workqueue);
out_destroy_log:
        destroy_workqueue(mp->m_log_workqueue);
out_destroy_reclaim:
        destroy_workqueue(mp->m_reclaim_workqueue);
out_destroy_cil:
        destroy_workqueue(mp->m_cil_workqueue);
out_destroy_unwritten:
        destroy_workqueue(mp->m_unwritten_workqueue);
out_destroy_data_iodone_queue:
        destroy_workqueue(mp->m_data_workqueue);
out_destroy_buf:
        destroy_workqueue(mp->m_buf_workqueue);
out:
        return -ENOMEM;
}

STATIC void
xfs_destroy_mount_workqueues(
        struct xfs_mount        *mp)
{
        destroy_workqueue(mp->m_sync_workqueue);
        destroy_workqueue(mp->m_eofblocks_workqueue);
        destroy_workqueue(mp->m_log_workqueue);
        destroy_workqueue(mp->m_reclaim_workqueue);
        destroy_workqueue(mp->m_cil_workqueue);
        destroy_workqueue(mp->m_data_workqueue);
        destroy_workqueue(mp->m_unwritten_workqueue);
        destroy_workqueue(mp->m_buf_workqueue);
}

/*
 * Flush all dirty data to disk. Must not be called while holding an XFS_ILOCK
 * or a page lock. We use sync_inodes_sb() here to ensure we block while waiting
 * for IO to complete so that we effectively throttle multiple callers to the
 * rate at which IO is completing.
 */
void
xfs_flush_inodes(
        struct xfs_mount        *mp)
{
        struct super_block      *sb = mp->m_super;

        if (down_read_trylock(&sb->s_umount)) {
                sync_inodes_sb(sb);
                up_read(&sb->s_umount);
        }
}

/* 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 inactivate and reclaim the inode.
 */
STATIC void
xfs_fs_destroy_inode(
        struct inode            *inode)
{
        struct xfs_inode        *ip = XFS_I(inode);

        trace_xfs_destroy_inode(ip);

        ASSERT(!rwsem_is_locked(&inode->i_rwsem));
        XFS_STATS_INC(ip->i_mount, vn_rele);
        XFS_STATS_INC(ip->i_mount, vn_remove);

        xfs_inactive(ip);

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

        /*
         * 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.
         */
        xfs_inode_set_reclaim_tag(ip);

}

static void
xfs_fs_dirty_inode(
        struct inode                    *inode,
        int                             flag)
{
        struct xfs_inode                *ip = XFS_I(inode);
        struct xfs_mount                *mp = ip->i_mount;
        struct xfs_trans                *tp;

        if (!(inode->i_sb->s_flags & SB_LAZYTIME))
                return;
        if (flag != I_DIRTY_SYNC || !(inode->i_state & I_DIRTY_TIME))
                return;

        if (xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp))
                return;
        xfs_ilock(ip, XFS_ILOCK_EXCL);
        xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
        xfs_trans_log_inode(tp, ip, XFS_ILOG_TIMESTAMP);
        xfs_trans_commit(tp);
}

/*
 * 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_pincount, 0);
        spin_lock_init(&ip->i_flags_lock);

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

/*
 * We do an unlocked check for XFS_IDONTCACHE here because we are already
 * serialised against cache hits here via the inode->i_lock and igrab() in
 * xfs_iget_cache_hit(). Hence a lookup that might clear this flag will not be
 * racing with us, and it avoids needing to grab a spinlock here for every inode
 * we drop the final reference on.
 */
STATIC int
xfs_fs_drop_inode(
        struct inode            *inode)
{
        struct xfs_inode        *ip = XFS_I(inode);

        /*
         * If this unlinked inode is in the middle of recovery, don't
         * drop the inode just yet; log recovery will take care of
         * that.  See the comment for this inode flag.
         */
        if (ip->i_flags & XFS_IRECOVERY) {
                ASSERT(ip->i_mount->m_log->l_flags & XLOG_RECOVERY_NEEDED);
                return 0;
        }

        return generic_drop_inode(inode) || (ip->i_flags & XFS_IDONTCACHE);
}

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

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

        /*
         * Doing anything during the async pass would be counterproductive.
         */
        if (!wait)
                return 0;

        xfs_log_force(mp, XFS_LOG_SYNC);
        if (laptop_mode) {
                /*
                 * The disk must be active because we're syncing.
                 * We schedule log work now (now that the disk is
                 * active) instead of later (when it might not be).
                 */
                flush_delayed_work(&mp->m_log->l_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(d_inode(dentry));
        uint64_t                fakeinos, id;
        uint64_t                icount;
        uint64_t                ifree;
        uint64_t                fdblocks;
        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);

        icount = percpu_counter_sum(&mp->m_icount);
        ifree = percpu_counter_sum(&mp->m_ifree);
        fdblocks = percpu_counter_sum(&mp->m_fdblocks);

        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;
        spin_unlock(&mp->m_sb_lock);

        statp->f_bfree = fdblocks - mp->m_alloc_set_aside;
        statp->f_bavail = statp->f_bfree;

        fakeinos = statp->f_bfree << sbp->sb_inopblog;
        statp->f_files = MIN(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);

        /* If sb_icount overshot maxicount, report actual allocation */
        statp->f_files = max_t(typeof(statp->f_files),
                                        statp->f_files,
                                        sbp->sb_icount);

        /* make sure statp->f_ffree does not underflow */
        ffree = statp->f_files - (icount - ifree);
        statp->f_ffree = max_t(int64_t, ffree, 0);


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

        if (XFS_IS_REALTIME_MOUNT(mp) &&
            (ip->i_d.di_flags & (XFS_DIFLAG_RTINHERIT | XFS_DIFLAG_REALTIME))) {
                statp->f_blocks = sbp->sb_rblocks;
                statp->f_bavail = statp->f_bfree =
                        sbp->sb_frextents * sbp->sb_rextsize;
        }

        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);
}

/*
 * Trigger writeback of all the dirty metadata in the file system.
 *
 * This ensures that the metadata is written to their location on disk rather
 * than just existing in transactions in the log. This means after a quiesce
 * there is no log replay required to write the inodes to disk - this is the
 * primary difference between a sync and a quiesce.
 *
 * Note: xfs_log_quiesce() stops background log work - the callers must ensure
 * it is started again when appropriate.
 */
void
xfs_quiesce_attr(
        struct xfs_mount        *mp)
{
        int     error = 0;

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

        /* force the log to unpin objects from the now complete transactions */
        xfs_log_force(mp, XFS_LOG_SYNC);

        /* reclaim inodes to do any IO before the freeze completes */
        xfs_reclaim_inodes(mp, 0);
        xfs_reclaim_inodes(mp, SYNC_WAIT);

        /* Push the superblock and write an unmount record */
        error = xfs_log_sbcount(mp);
        if (error)
                xfs_warn(mp, "xfs_attr_quiesce: failed to log sb changes. "
                                "Frozen image may not be consistent.");
        /*
         * Just warn here till VFS can correctly support
         * read-only remount without racing.
         */
        WARN_ON(atomic_read(&mp->m_active_trans) != 0);

        xfs_log_quiesce(mp);
}

STATIC int
xfs_test_remount_options(
        struct super_block      *sb,
        char                    *options)
{
        int                     error = 0;
        struct xfs_mount        *tmp_mp;

        tmp_mp = kmem_zalloc(sizeof(*tmp_mp), KM_MAYFAIL);
        if (!tmp_mp)
                return -ENOMEM;

        tmp_mp->m_super = sb;
        error = xfs_parseargs(tmp_mp, options);
        xfs_free_fsname(tmp_mp);
        kmem_free(tmp_mp);

        return error;
}

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

        /* First, check for complete junk; i.e. invalid options */
        error = xfs_test_remount_options(sb, options);
        if (error)
                return error;

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

                if (!*p)
                        continue;

                token = match_token(p, tokens, args);
                switch (token) {
                case Opt_barrier:
                        xfs_warn(mp, "%s option is deprecated, ignoring.", p);
                        mp->m_flags |= XFS_MOUNT_BARRIER;
                        break;
                case Opt_nobarrier:
                        xfs_warn(mp, "%s option is deprecated, ignoring.", p);
                        mp->m_flags &= ~XFS_MOUNT_BARRIER;
                        break;
                case Opt_inode64:
                        mp->m_flags &= ~XFS_MOUNT_SMALL_INUMS;
                        mp->m_maxagi = xfs_set_inode_alloc(mp, sbp->sb_agcount);
                        break;
                case Opt_inode32:
                        mp->m_flags |= XFS_MOUNT_SMALL_INUMS;
                        mp->m_maxagi = xfs_set_inode_alloc(mp, sbp->sb_agcount);
                        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", p);
                        return -EINVAL;
#else
                        break;
#endif
                }
        }

        /* ro -> rw */
        if ((mp->m_flags & XFS_MOUNT_RDONLY) && !(*flags & SB_RDONLY)) {
                if (mp->m_flags & XFS_MOUNT_NORECOVERY) {
                        xfs_warn(mp,
                "ro->rw transition prohibited on norecovery mount");
                        return -EINVAL;
                }

                if (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
                    xfs_sb_has_ro_compat_feature(sbp,
                                        XFS_SB_FEAT_RO_COMPAT_UNKNOWN)) {
                        xfs_warn(mp,
"ro->rw transition prohibited on unknown (0x%x) ro-compat filesystem",
                                (sbp->sb_features_ro_compat &
                                        XFS_SB_FEAT_RO_COMPAT_UNKNOWN));
                        return -EINVAL;
                }

                mp->m_flags &= ~XFS_MOUNT_RDONLY;

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

                /*
                 * 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);
                xfs_log_work_queue(mp);
                xfs_queue_eofblocks(mp);

                /* Recover any CoW blocks that never got remapped. */
                error = xfs_reflink_recover_cow(mp);
                if (error) {
                        xfs_err(mp,
        "Error %d recovering leftover CoW allocations.", error);
                        xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
                        return error;
                }
                xfs_queue_cowblocks(mp);

                /* Create the per-AG metadata reservation pool .*/
                error = xfs_fs_reserve_ag_blocks(mp);
                if (error && error != -ENOSPC)
                        return error;
        }

        /* rw -> ro */
        if (!(mp->m_flags & XFS_MOUNT_RDONLY) && (*flags & SB_RDONLY)) {
                /* Get rid of any leftover CoW reservations... */
                cancel_delayed_work_sync(&mp->m_cowblocks_work);
                error = xfs_icache_free_cowblocks(mp, NULL);
                if (error) {
                        xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
                        return error;
                }

                /* Free the per-AG metadata reservation pool. */
                error = xfs_fs_unreserve_ag_blocks(mp);
                if (error) {
                        xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
                        return error;
                }

                /*
                 * 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_save_resvblks(mp);

                /*
                 * Cancel background eofb scanning so it cannot race with the
                 * final log force+buftarg wait and deadlock the remount.
                 */
                cancel_delayed_work_sync(&mp->m_eofblocks_work);

                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 sync the superblock
 * to the log to dirty it in case of a crash while frozen. This ensures that we
 * will recover the unlinked inode lists on the next mount.
 */
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_sync_sb(mp, true);
}

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

        xfs_restore_resvblks(mp);
        xfs_log_work_queue(mp);
        return 0;
}

STATIC int
xfs_fs_show_options(
        struct seq_file         *m,
        struct dentry           *root)
{
        return xfs_showargs(XFS_M(root->d_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 -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 -EINVAL;
                }
        }

        /*
         * V5 filesystems always use attr2 format for attributes.
         */
        if (xfs_sb_version_hascrc(&mp->m_sb) &&
            (mp->m_flags & XFS_MOUNT_NOATTR2)) {
                xfs_warn(mp, "Cannot mount a V5 filesystem as noattr2. "
                             "attr2 is always enabled for V5 filesystems.");
                return -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 -EROFS;
        }

        if ((mp->m_qflags & (XFS_GQUOTA_ACCT | XFS_GQUOTA_ACTIVE)) &&
            (mp->m_qflags & (XFS_PQUOTA_ACCT | XFS_PQUOTA_ACTIVE)) &&
            !xfs_sb_version_has_pquotino(&mp->m_sb)) {
                xfs_warn(mp,
                  "Super block does not support project and group quota together");
                return -EINVAL;
        }

        return 0;
}

static int
xfs_init_percpu_counters(
        struct xfs_mount        *mp)
{
        int             error;

        error = percpu_counter_init(&mp->m_icount, 0, GFP_KERNEL);
        if (error)
                return -ENOMEM;

        error = percpu_counter_init(&mp->m_ifree, 0, GFP_KERNEL);
        if (error)
                goto free_icount;

        error = percpu_counter_init(&mp->m_fdblocks, 0, GFP_KERNEL);
        if (error)
                goto free_ifree;

        return 0;

free_ifree:
        percpu_counter_destroy(&mp->m_ifree);
free_icount:
        percpu_counter_destroy(&mp->m_icount);
        return -ENOMEM;
}

void
xfs_reinit_percpu_counters(
        struct xfs_mount        *mp)
{
        percpu_counter_set(&mp->m_icount, mp->m_sb.sb_icount);
        percpu_counter_set(&mp->m_ifree, mp->m_sb.sb_ifree);
        percpu_counter_set(&mp->m_fdblocks, mp->m_sb.sb_fdblocks);
}

static void
xfs_destroy_percpu_counters(
        struct xfs_mount        *mp)
{
        percpu_counter_destroy(&mp->m_icount);
        percpu_counter_destroy(&mp->m_ifree);
        percpu_counter_destroy(&mp->m_fdblocks);
}

static struct xfs_mount *
xfs_mount_alloc(
        struct super_block      *sb)
{
        struct xfs_mount        *mp;

        mp = kzalloc(sizeof(struct xfs_mount), GFP_KERNEL);
        if (!mp)
                return NULL;

        mp->m_super = sb;
        spin_lock_init(&mp->m_sb_lock);
        spin_lock_init(&mp->m_agirotor_lock);
        INIT_RADIX_TREE(&mp->m_perag_tree, GFP_ATOMIC);
        spin_lock_init(&mp->m_perag_lock);
        mutex_init(&mp->m_growlock);
        atomic_set(&mp->m_active_trans, 0);
        INIT_DELAYED_WORK(&mp->m_reclaim_work, xfs_reclaim_worker);
        INIT_DELAYED_WORK(&mp->m_eofblocks_work, xfs_eofblocks_worker);
        INIT_DELAYED_WORK(&mp->m_cowblocks_work, xfs_cowblocks_worker);
        mp->m_kobj.kobject.kset = xfs_kset;
        return mp;
}


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;

        /*
         * allocate mp and do all low-level struct initializations before we
         * attach it to the super
         */
        mp = xfs_mount_alloc(sb);
        if (!mp)
                goto out;
        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;
        sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP | QTYPE_MASK_PRJ;
#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_init_mount_workqueues(mp);
        if (error)
                goto out_close_devices;

        error = xfs_init_percpu_counters(mp);
        if (error)
                goto out_destroy_workqueues;

        /* Allocate stats memory before we do operations that might use it */
        mp->m_stats.xs_stats = alloc_percpu(struct xfsstats);
        if (!mp->m_stats.xs_stats) {
                error = -ENOMEM;
                goto out_destroy_counters;
        }

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

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

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

        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.
         */
        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_max_links = XFS_MAXLINK;
        sb->s_time_gran = 1;
        set_posix_acl_flag(sb);

        /* version 5 superblocks support inode version counters. */
        if (XFS_SB_VERSION_NUM(&mp->m_sb) == XFS_SB_VERSION_5)
                sb->s_flags |= SB_I_VERSION;

        if (mp->m_flags & XFS_MOUNT_DAX) {
                xfs_warn(mp,
                "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");

                error = bdev_dax_supported(sb, sb->s_blocksize);
                if (error) {
                        xfs_alert(mp,
                        "DAX unsupported by block device. Turning off DAX.");
                        mp->m_flags &= ~XFS_MOUNT_DAX;
                }
                if (xfs_sb_version_hasreflink(&mp->m_sb)) {
                        xfs_alert(mp,
                "DAX and reflink cannot be used together!");
                        error = -EINVAL;
                        goto out_filestream_unmount;
                }
        }

        if (mp->m_flags & XFS_MOUNT_DISCARD) {
                struct request_queue *q = bdev_get_queue(sb->s_bdev);

                if (!blk_queue_discard(q)) {
                        xfs_warn(mp, "mounting with \"discard\" option, but "
                                        "the device does not support discard");
                        mp->m_flags &= ~XFS_MOUNT_DISCARD;
                }
        }

        if (xfs_sb_version_hasreflink(&mp->m_sb) && mp->m_sb.sb_rblocks) {
                xfs_alert(mp,
        "reflink not compatible with realtime device!");
                error = -EINVAL;
                goto out_filestream_unmount;
        }

        if (xfs_sb_version_hasrmapbt(&mp->m_sb) && mp->m_sb.sb_rblocks) {
                xfs_alert(mp,
        "reverse mapping btree not compatible with realtime device!");
                error = -EINVAL;
                goto out_filestream_unmount;
        }

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

        root = igrab(VFS_I(mp->m_rootip));
        if (!root) {
                error = -ENOENT;
                goto out_unmount;
        }
        sb->s_root = d_make_root(root);
        if (!sb->s_root) {
                error = -ENOMEM;
                goto out_unmount;
        }

        return 0;

 out_filestream_unmount:
        xfs_filestream_unmount(mp);
 out_free_sb:
        xfs_freesb(mp);
 out_free_stats:
        free_percpu(mp->m_stats.xs_stats);
 out_destroy_counters:
        xfs_destroy_percpu_counters(mp);
 out_destroy_workqueues:
        xfs_destroy_mount_workqueues(mp);
 out_close_devices:
        xfs_close_devices(mp);
 out_free_fsname:
        xfs_free_fsname(mp);
        kfree(mp);
 out:
        return error;

 out_unmount:
        xfs_filestream_unmount(mp);
        xfs_unmountfs(mp);
        goto out_free_sb;
}

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

        xfs_notice(mp, "Unmounting Filesystem");
        xfs_filestream_unmount(mp);
        xfs_unmountfs(mp);

        xfs_freesb(mp);
        free_percpu(mp->m_stats.xs_stats);
        xfs_destroy_percpu_counters(mp);
        xfs_destroy_mount_workqueues(mp);
        xfs_close_devices(mp);
        xfs_free_fsname(mp);
        kfree(mp);
}

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 long
xfs_fs_nr_cached_objects(
        struct super_block      *sb,
        struct shrink_control   *sc)
{
        return xfs_reclaim_inodes_count(XFS_M(sb));
}

static long
xfs_fs_free_cached_objects(
        struct super_block      *sb,
        struct shrink_control   *sc)
{
        return xfs_reclaim_inodes_nr(XFS_M(sb), sc->nr_to_scan);
}

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,
        .drop_inode             = xfs_fs_drop_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,
        .nr_cached_objects      = xfs_fs_nr_cached_objects,
        .free_cached_objects    = xfs_fs_free_cached_objects,
};

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,
};
MODULE_ALIAS_FS("xfs");

STATIC int __init
xfs_init_zones(void)
{
        xfs_ioend_bioset = bioset_create(4 * MAX_BUF_PER_PAGE,
                        offsetof(struct xfs_ioend, io_inline_bio),
                        BIOSET_NEED_BVECS);
        if (!xfs_ioend_bioset)
                goto out;

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

        xfs_bmap_free_item_zone = kmem_zone_init(
                        sizeof(struct xfs_extent_free_item),
                        "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_ifork_zone = kmem_zone_init(sizeof(xfs_ifork_t), "xfs_ifork");
        if (!xfs_ifork_zone)
                goto out_destroy_da_state_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(struct xfs_buf_log_item),
                                           "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 |
                        KM_ZONE_ACCOUNT, 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;
        xfs_icreate_zone = kmem_zone_init(sizeof(struct xfs_icreate_item),
                                        "xfs_icr");
        if (!xfs_icreate_zone)
                goto out_destroy_ili_zone;

        xfs_rud_zone = kmem_zone_init(sizeof(struct xfs_rud_log_item),
                        "xfs_rud_item");
        if (!xfs_rud_zone)
                goto out_destroy_icreate_zone;

        xfs_rui_zone = kmem_zone_init(
                        xfs_rui_log_item_sizeof(XFS_RUI_MAX_FAST_EXTENTS),
                        "xfs_rui_item");
        if (!xfs_rui_zone)
                goto out_destroy_rud_zone;

        xfs_cud_zone = kmem_zone_init(sizeof(struct xfs_cud_log_item),
                        "xfs_cud_item");
        if (!xfs_cud_zone)
                goto out_destroy_rui_zone;

        xfs_cui_zone = kmem_zone_init(
                        xfs_cui_log_item_sizeof(XFS_CUI_MAX_FAST_EXTENTS),
                        "xfs_cui_item");
        if (!xfs_cui_zone)
                goto out_destroy_cud_zone;

        xfs_bud_zone = kmem_zone_init(sizeof(struct xfs_bud_log_item),
                        "xfs_bud_item");
        if (!xfs_bud_zone)
                goto out_destroy_cui_zone;

        xfs_bui_zone = kmem_zone_init(
                        xfs_bui_log_item_sizeof(XFS_BUI_MAX_FAST_EXTENTS),
                        "xfs_bui_item");
        if (!xfs_bui_zone)
                goto out_destroy_bud_zone;

        return 0;

 out_destroy_bud_zone:
        kmem_zone_destroy(xfs_bud_zone);
 out_destroy_cui_zone:
        kmem_zone_destroy(xfs_cui_zone);
 out_destroy_cud_zone:
        kmem_zone_destroy(xfs_cud_zone);
 out_destroy_rui_zone:
        kmem_zone_destroy(xfs_rui_zone);
 out_destroy_rud_zone:
        kmem_zone_destroy(xfs_rud_zone);
 out_destroy_icreate_zone:
        kmem_zone_destroy(xfs_icreate_zone);
 out_destroy_ili_zone:
        kmem_zone_destroy(xfs_ili_zone);
 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_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_free_ioend_bioset:
        bioset_free(xfs_ioend_bioset);

 out:
        return -ENOMEM;
}

STATIC void
xfs_destroy_zones(void)
{
        /*
         * Make sure all delayed rcu free are flushed before we
         * destroy caches.
         */
        rcu_barrier();
        kmem_zone_destroy(xfs_bui_zone);
        kmem_zone_destroy(xfs_bud_zone);
        kmem_zone_destroy(xfs_cui_zone);
        kmem_zone_destroy(xfs_cud_zone);
        kmem_zone_destroy(xfs_rui_zone);
        kmem_zone_destroy(xfs_rud_zone);
        kmem_zone_destroy(xfs_icreate_zone);
        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_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);
        bioset_free(xfs_ioend_bioset);
}

STATIC int __init
xfs_init_workqueues(void)
{
        /*
         * The allocation workqueue can be used in memory reclaim situations
         * (writepage path), and parallelism is only limited by the number of
         * AGs in all the filesystems mounted. Hence use the default large
         * max_active value for this workqueue.
         */
        xfs_alloc_wq = alloc_workqueue("xfsalloc",
                        WQ_MEM_RECLAIM|WQ_FREEZABLE, 0);
        if (!xfs_alloc_wq)
                return -ENOMEM;

        xfs_discard_wq = alloc_workqueue("xfsdiscard", WQ_UNBOUND, 0);
        if (!xfs_discard_wq)
                goto out_free_alloc_wq;

        return 0;
out_free_alloc_wq:
        destroy_workqueue(xfs_alloc_wq);
        return -ENOMEM;
}

STATIC void
xfs_destroy_workqueues(void)
{
        destroy_workqueue(xfs_discard_wq);
        destroy_workqueue(xfs_alloc_wq);
}

STATIC int __init
init_xfs_fs(void)
{
        int                     error;

        xfs_check_ondisk_structs();

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

        xfs_extent_free_init_defer_op();
        xfs_rmap_update_init_defer_op();
        xfs_refcount_update_init_defer_op();
        xfs_bmap_update_init_defer_op();

        xfs_dir_startup();

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

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

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

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

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

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

        xfs_kset = kset_create_and_add("xfs", NULL, fs_kobj);
        if (!xfs_kset) {
                error = -ENOMEM;
                goto out_sysctl_unregister;
        }

        xfsstats.xs_kobj.kobject.kset = xfs_kset;

        xfsstats.xs_stats = alloc_percpu(struct xfsstats);
        if (!xfsstats.xs_stats) {
                error = -ENOMEM;
                goto out_kset_unregister;
        }

        error = xfs_sysfs_init(&xfsstats.xs_kobj, &xfs_stats_ktype, NULL,
                               "stats");
        if (error)
                goto out_free_stats;

#ifdef DEBUG
        xfs_dbg_kobj.kobject.kset = xfs_kset;
        error = xfs_sysfs_init(&xfs_dbg_kobj, &xfs_dbg_ktype, NULL, "debug");
        if (error)
                goto out_remove_stats_kobj;
#endif

        error = xfs_qm_init();
        if (error)
                goto out_remove_dbg_kobj;

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

 out_qm_exit:
        xfs_qm_exit();
 out_remove_dbg_kobj:
#ifdef DEBUG
        xfs_sysfs_del(&xfs_dbg_kobj);
 out_remove_stats_kobj:
#endif
        xfs_sysfs_del(&xfsstats.xs_kobj);
 out_free_stats:
        free_percpu(xfsstats.xs_stats);
 out_kset_unregister:
        kset_unregister(xfs_kset);
 out_sysctl_unregister:
        xfs_sysctl_unregister();
 out_cleanup_procfs:
        xfs_cleanup_procfs();
 out_buf_terminate:
        xfs_buf_terminate();
 out_mru_cache_uninit:
        xfs_mru_cache_uninit();
 out_destroy_wq:
        xfs_destroy_workqueues();
 out_destroy_zones:
        xfs_destroy_zones();
 out:
        return error;
}

STATIC void __exit
exit_xfs_fs(void)
{
        xfs_qm_exit();
        unregister_filesystem(&xfs_fs_type);
#ifdef DEBUG
        xfs_sysfs_del(&xfs_dbg_kobj);
#endif
        xfs_sysfs_del(&xfsstats.xs_kobj);
        free_percpu(xfsstats.xs_stats);
        kset_unregister(xfs_kset);
        xfs_sysctl_unregister();
        xfs_cleanup_procfs();
        xfs_buf_terminate();
        xfs_mru_cache_uninit();
        xfs_destroy_workqueues();
        xfs_destroy_zones();
        xfs_uuid_table_free();
}

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");