xfs_iops.c

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

#include <linux/capability.h>
#include <linux/xattr.h>
#include <linux/namei.h>
#include <linux/posix_acl.h>
#include <linux/security.h>
#include <linux/fiemap.h>
#include <linux/slab.h>

static int
xfs_initxattrs(
    struct inode        *inode,
    const struct xattr  *xattr_array,
    void            *fs_info)
{
    const struct xattr  *xattr;
    struct xfs_inode    *ip = XFS_I(inode);
    int         error = 0;

    for (xattr = xattr_array; xattr->name != NULL; xattr++) {
        error = xfs_attr_set(ip, xattr->name, xattr->value,
                     xattr->value_len, ATTR_SECURE);
        if (error < 0)
            break;
    }
    return error;
}

/*
 * Hook in SELinux.  This is not quite correct yet, what we really need
 * here (as we do for default ACLs) is a mechanism by which creation of
 * these attrs can be journalled at inode creation time (along with the
 * inode, of course, such that log replay can't cause these to be lost).
 */

STATIC int
xfs_init_security(
    struct inode    *inode,
    struct inode    *dir,
    const struct qstr *qstr)
{
    return security_inode_init_security(inode, dir, qstr,
                        &xfs_initxattrs, NULL);
}

static void
xfs_dentry_to_name(
    struct xfs_name *namep,
    struct dentry   *dentry)
{
    namep->name = dentry->d_name.name;
    namep->len = dentry->d_name.len;
}

STATIC void
xfs_cleanup_inode(
    struct inode    *dir,
    struct inode    *inode,
    struct dentry   *dentry)
{
    struct xfs_name teardown;

    /* Oh, the horror.
     * If we can't add the ACL or we fail in
     * xfs_init_security we must back out.
     * ENOSPC can hit here, among other things.
     */
    xfs_dentry_to_name(&teardown, dentry);

    xfs_remove(XFS_I(dir), &teardown, XFS_I(inode));
    iput(inode);
}

STATIC int
xfs_vn_mknod(
    struct inode    *dir,
    struct dentry   *dentry,
    umode_t     mode,
    dev_t       rdev)
{
    struct inode    *inode;
    struct xfs_inode *ip = NULL;
    struct posix_acl *default_acl = NULL;
    struct xfs_name name;
    int     error;

    /*
     * Irix uses Missed'em'V split, but doesn't want to see
     * the upper 5 bits of (14bit) major.
     */
    if (S_ISCHR(mode) || S_ISBLK(mode)) {
        if (unlikely(!sysv_valid_dev(rdev) || MAJOR(rdev) & ~0x1ff))
            return -EINVAL;
        rdev = sysv_encode_dev(rdev);
    } else {
        rdev = 0;
    }

    if (IS_POSIXACL(dir)) {
        default_acl = xfs_get_acl(dir, ACL_TYPE_DEFAULT);
        if (IS_ERR(default_acl))
            return PTR_ERR(default_acl);

        if (!default_acl)
            mode &= ~current_umask();
    }

    xfs_dentry_to_name(&name, dentry);
    error = xfs_create(XFS_I(dir), &name, mode, rdev, &ip);
    if (unlikely(error))
        goto out_free_acl;

    inode = VFS_I(ip);

    error = xfs_init_security(inode, dir, &dentry->d_name);
    if (unlikely(error))
        goto out_cleanup_inode;

    if (default_acl) {
        error = -xfs_inherit_acl(inode, default_acl);
        default_acl = NULL;
        if (unlikely(error))
            goto out_cleanup_inode;
    }


    d_instantiate(dentry, inode);
    return -error;

 out_cleanup_inode:
    xfs_cleanup_inode(dir, inode, dentry);
 out_free_acl:
    posix_acl_release(default_acl);
    return -error;
}

STATIC int
xfs_vn_create(
    struct inode    *dir,
    struct dentry   *dentry,
    umode_t     mode,
    bool        flags)
{
    return xfs_vn_mknod(dir, dentry, mode, 0);
}

STATIC int
xfs_vn_mkdir(
    struct inode    *dir,
    struct dentry   *dentry,
    umode_t     mode)
{
    return xfs_vn_mknod(dir, dentry, mode|S_IFDIR, 0);
}

STATIC struct dentry *
xfs_vn_lookup(
    struct inode    *dir,
    struct dentry   *dentry,
    unsigned int flags)
{
    struct xfs_inode *cip;
    struct xfs_name name;
    int     error;

    if (dentry->d_name.len >= MAXNAMELEN)
        return ERR_PTR(-ENAMETOOLONG);

    xfs_dentry_to_name(&name, dentry);
    error = xfs_lookup(XFS_I(dir), &name, &cip, NULL);
    if (unlikely(error)) {
        if (unlikely(error != ENOENT))
            return ERR_PTR(-error);
        d_add(dentry, NULL);
        return NULL;
    }

    return d_splice_alias(VFS_I(cip), dentry);
}

STATIC struct dentry *
xfs_vn_ci_lookup(
    struct inode    *dir,
    struct dentry   *dentry,
    unsigned int flags)
{
    struct xfs_inode *ip;
    struct xfs_name xname;
    struct xfs_name ci_name;
    struct qstr dname;
    int     error;

    if (dentry->d_name.len >= MAXNAMELEN)
        return ERR_PTR(-ENAMETOOLONG);

    xfs_dentry_to_name(&xname, dentry);
    error = xfs_lookup(XFS_I(dir), &xname, &ip, &ci_name);
    if (unlikely(error)) {
        if (unlikely(error != ENOENT))
            return ERR_PTR(-error);
        /*
         * call d_add(dentry, NULL) here when d_drop_negative_children
         * is called in xfs_vn_mknod (ie. allow negative dentries
         * with CI filesystems).
         */
        return NULL;
    }

    /* if exact match, just splice and exit */
    if (!ci_name.name)
        return d_splice_alias(VFS_I(ip), dentry);

    /* else case-insensitive match... */
    dname.name = ci_name.name;
    dname.len = ci_name.len;
    dentry = d_add_ci(dentry, VFS_I(ip), &dname);
    kmem_free(ci_name.name);
    return dentry;
}

STATIC int
xfs_vn_link(
    struct dentry   *old_dentry,
    struct inode    *dir,
    struct dentry   *dentry)
{
    struct inode    *inode = old_dentry->d_inode;
    struct xfs_name name;
    int     error;

    xfs_dentry_to_name(&name, dentry);

    error = xfs_link(XFS_I(dir), XFS_I(inode), &name);
    if (unlikely(error))
        return -error;

    ihold(inode);
    d_instantiate(dentry, inode);
    return 0;
}

STATIC int
xfs_vn_unlink(
    struct inode    *dir,
    struct dentry   *dentry)
{
    struct xfs_name name;
    int     error;

    xfs_dentry_to_name(&name, dentry);

    error = -xfs_remove(XFS_I(dir), &name, XFS_I(dentry->d_inode));
    if (error)
        return error;

    /*
     * With unlink, the VFS makes the dentry "negative": no inode,
     * but still hashed. This is incompatible with case-insensitive
     * mode, so invalidate (unhash) the dentry in CI-mode.
     */
    if (xfs_sb_version_hasasciici(&XFS_M(dir->i_sb)->m_sb))
        d_invalidate(dentry);
    return 0;
}

STATIC int
xfs_vn_symlink(
    struct inode    *dir,
    struct dentry   *dentry,
    const char  *symname)
{
    struct inode    *inode;
    struct xfs_inode *cip = NULL;
    struct xfs_name name;
    int     error;
    umode_t     mode;

    mode = S_IFLNK |
        (irix_symlink_mode ? 0777 & ~current_umask() : S_IRWXUGO);
    xfs_dentry_to_name(&name, dentry);

    error = xfs_symlink(XFS_I(dir), &name, symname, mode, &cip);
    if (unlikely(error))
        goto out;

    inode = VFS_I(cip);

    error = xfs_init_security(inode, dir, &dentry->d_name);
    if (unlikely(error))
        goto out_cleanup_inode;

    d_instantiate(dentry, inode);
    return 0;

 out_cleanup_inode:
    xfs_cleanup_inode(dir, inode, dentry);
 out:
    return -error;
}

STATIC int
xfs_vn_rename(
    struct inode    *odir,
    struct dentry   *odentry,
    struct inode    *ndir,
    struct dentry   *ndentry)
{
    struct inode    *new_inode = ndentry->d_inode;
    struct xfs_name oname;
    struct xfs_name nname;

    xfs_dentry_to_name(&oname, odentry);
    xfs_dentry_to_name(&nname, ndentry);

    return -xfs_rename(XFS_I(odir), &oname, XFS_I(odentry->d_inode),
               XFS_I(ndir), &nname, new_inode ?
                        XFS_I(new_inode) : NULL);
}

/*
 * careful here - this function can get called recursively, so
 * we need to be very careful about how much stack we use.
 * uio is kmalloced for this reason...
 */
STATIC void *
xfs_vn_follow_link(
    struct dentry       *dentry,
    struct nameidata    *nd)
{
    char            *link;
    int         error = -ENOMEM;

    link = kmalloc(MAXPATHLEN+1, GFP_KERNEL);
    if (!link)
        goto out_err;

    error = -xfs_readlink(XFS_I(dentry->d_inode), link);
    if (unlikely(error))
        goto out_kfree;

    nd_set_link(nd, link);
    return NULL;

 out_kfree:
    kfree(link);
 out_err:
    nd_set_link(nd, ERR_PTR(error));
    return NULL;
}

STATIC void
xfs_vn_put_link(
    struct dentry   *dentry,
    struct nameidata *nd,
    void        *p)
{
    char        *s = nd_get_link(nd);

    if (!IS_ERR(s))
        kfree(s);
}

STATIC int
xfs_vn_getattr(
    struct vfsmount     *mnt,
    struct dentry       *dentry,
    struct kstat        *stat)
{
    struct inode        *inode = dentry->d_inode;
    struct xfs_inode    *ip = XFS_I(inode);
    struct xfs_mount    *mp = ip->i_mount;

    trace_xfs_getattr(ip);

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

    stat->size = XFS_ISIZE(ip);
    stat->dev = inode->i_sb->s_dev;
    stat->mode = ip->i_d.di_mode;
    stat->nlink = ip->i_d.di_nlink;
    stat->uid = ip->i_d.di_uid;
    stat->gid = ip->i_d.di_gid;
    stat->ino = ip->i_ino;
    stat->atime = inode->i_atime;
    stat->mtime = inode->i_mtime;
    stat->ctime = inode->i_ctime;
    stat->blocks =
        XFS_FSB_TO_BB(mp, ip->i_d.di_nblocks + ip->i_delayed_blks);


    switch (inode->i_mode & S_IFMT) {
    case S_IFBLK:
    case S_IFCHR:
        stat->blksize = BLKDEV_IOSIZE;
        stat->rdev = MKDEV(sysv_major(ip->i_df.if_u2.if_rdev) & 0x1ff,
                   sysv_minor(ip->i_df.if_u2.if_rdev));
        break;
    default:
        if (XFS_IS_REALTIME_INODE(ip)) {
            /*
             * If the file blocks are being allocated from a
             * realtime volume, then return the inode's realtime
             * extent size or the realtime volume's extent size.
             */
            stat->blksize =
                xfs_get_extsz_hint(ip) << mp->m_sb.sb_blocklog;
        } else
            stat->blksize = xfs_preferred_iosize(mp);
        stat->rdev = 0;
        break;
    }

    return 0;
}

int
xfs_setattr_nonsize(
    struct xfs_inode    *ip,
    struct iattr        *iattr,
    int         flags)
{
    xfs_mount_t     *mp = ip->i_mount;
    struct inode        *inode = VFS_I(ip);
    int         mask = iattr->ia_valid;
    xfs_trans_t     *tp;
    int         error;
    uid_t           uid = 0, iuid = 0;
    gid_t           gid = 0, igid = 0;
    struct xfs_dquot    *udqp = NULL, *gdqp = NULL;
    struct xfs_dquot    *olddquot1 = NULL, *olddquot2 = NULL;

    trace_xfs_setattr(ip);

    if (mp->m_flags & XFS_MOUNT_RDONLY)
        return XFS_ERROR(EROFS);

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

    error = -inode_change_ok(inode, iattr);
    if (error)
        return XFS_ERROR(error);

    ASSERT((mask & ATTR_SIZE) == 0);

    /*
     * If disk quotas is on, we make sure that the dquots do exist on disk,
     * before we start any other transactions. Trying to do this later
     * is messy. We don't care to take a readlock to look at the ids
     * in inode here, because we can't hold it across the trans_reserve.
     * If the IDs do change before we take the ilock, we're covered
     * because the i_*dquot fields will get updated anyway.
     */
    if (XFS_IS_QUOTA_ON(mp) && (mask & (ATTR_UID|ATTR_GID))) {
        uint    qflags = 0;

        if ((mask & ATTR_UID) && XFS_IS_UQUOTA_ON(mp)) {
            uid = iattr->ia_uid;
            qflags |= XFS_QMOPT_UQUOTA;
        } else {
            uid = ip->i_d.di_uid;
        }
        if ((mask & ATTR_GID) && XFS_IS_GQUOTA_ON(mp)) {
            gid = iattr->ia_gid;
            qflags |= XFS_QMOPT_GQUOTA;
        }  else {
            gid = ip->i_d.di_gid;
        }

        /*
         * We take a reference when we initialize udqp and gdqp,
         * so it is important that we never blindly double trip on
         * the same variable. See xfs_create() for an example.
         */
        ASSERT(udqp == NULL);
        ASSERT(gdqp == NULL);
        error = xfs_qm_vop_dqalloc(ip, uid, gid, xfs_get_projid(ip),
                     qflags, &udqp, &gdqp);
        if (error)
            return error;
    }

    tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_NOT_SIZE);
    error = xfs_trans_reserve(tp, 0, XFS_ICHANGE_LOG_RES(mp), 0, 0, 0);
    if (error)
        goto out_dqrele;

    xfs_ilock(ip, XFS_ILOCK_EXCL);

    /*
     * Change file ownership.  Must be the owner or privileged.
     */
    if (mask & (ATTR_UID|ATTR_GID)) {
        /*
         * These IDs could have changed since we last looked at them.
         * But, we're assured that if the ownership did change
         * while we didn't have the inode locked, inode's dquot(s)
         * would have changed also.
         */
        iuid = ip->i_d.di_uid;
        igid = ip->i_d.di_gid;
        gid = (mask & ATTR_GID) ? iattr->ia_gid : igid;
        uid = (mask & ATTR_UID) ? iattr->ia_uid : iuid;

        /*
         * Do a quota reservation only if uid/gid is actually
         * going to change.
         */
        if (XFS_IS_QUOTA_RUNNING(mp) &&
            ((XFS_IS_UQUOTA_ON(mp) && iuid != uid) ||
             (XFS_IS_GQUOTA_ON(mp) && igid != gid))) {
            ASSERT(tp);
            error = xfs_qm_vop_chown_reserve(tp, ip, udqp, gdqp,
                        capable(CAP_FOWNER) ?
                        XFS_QMOPT_FORCE_RES : 0);
            if (error)  /* out of quota */
                goto out_trans_cancel;
        }
    }

    xfs_trans_ijoin(tp, ip, 0);

    /*
     * Change file ownership.  Must be the owner or privileged.
     */
    if (mask & (ATTR_UID|ATTR_GID)) {
        /*
         * CAP_FSETID overrides the following restrictions:
         *
         * The set-user-ID and set-group-ID bits of a file will be
         * cleared upon successful return from chown()
         */
        if ((ip->i_d.di_mode & (S_ISUID|S_ISGID)) &&
            !capable(CAP_FSETID))
            ip->i_d.di_mode &= ~(S_ISUID|S_ISGID);

        /*
         * Change the ownerships and register quota modifications
         * in the transaction.
         */
        if (iuid != uid) {
            if (XFS_IS_QUOTA_RUNNING(mp) && XFS_IS_UQUOTA_ON(mp)) {
                ASSERT(mask & ATTR_UID);
                ASSERT(udqp);
                olddquot1 = xfs_qm_vop_chown(tp, ip,
                            &ip->i_udquot, udqp);
            }
            ip->i_d.di_uid = uid;
            inode->i_uid = uid;
        }
        if (igid != gid) {
            if (XFS_IS_QUOTA_RUNNING(mp) && XFS_IS_GQUOTA_ON(mp)) {
                ASSERT(!XFS_IS_PQUOTA_ON(mp));
                ASSERT(mask & ATTR_GID);
                ASSERT(gdqp);
                olddquot2 = xfs_qm_vop_chown(tp, ip,
                            &ip->i_gdquot, gdqp);
            }
            ip->i_d.di_gid = gid;
            inode->i_gid = gid;
        }
    }

    /*
     * Change file access modes.
     */
    if (mask & ATTR_MODE) {
        umode_t mode = iattr->ia_mode;

        if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
            mode &= ~S_ISGID;

        ip->i_d.di_mode &= S_IFMT;
        ip->i_d.di_mode |= mode & ~S_IFMT;

        inode->i_mode &= S_IFMT;
        inode->i_mode |= mode & ~S_IFMT;
    }

    /*
     * Change file access or modified times.
     */
    if (mask & ATTR_ATIME) {
        inode->i_atime = iattr->ia_atime;
        ip->i_d.di_atime.t_sec = iattr->ia_atime.tv_sec;
        ip->i_d.di_atime.t_nsec = iattr->ia_atime.tv_nsec;
    }
    if (mask & ATTR_CTIME) {
        inode->i_ctime = iattr->ia_ctime;
        ip->i_d.di_ctime.t_sec = iattr->ia_ctime.tv_sec;
        ip->i_d.di_ctime.t_nsec = iattr->ia_ctime.tv_nsec;
    }
    if (mask & ATTR_MTIME) {
        inode->i_mtime = iattr->ia_mtime;
        ip->i_d.di_mtime.t_sec = iattr->ia_mtime.tv_sec;
        ip->i_d.di_mtime.t_nsec = iattr->ia_mtime.tv_nsec;
    }

    xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

    XFS_STATS_INC(xs_ig_attrchg);

    if (mp->m_flags & XFS_MOUNT_WSYNC)
        xfs_trans_set_sync(tp);
    error = xfs_trans_commit(tp, 0);

    xfs_iunlock(ip, XFS_ILOCK_EXCL);

    /*
     * Release any dquot(s) the inode had kept before chown.
     */
    xfs_qm_dqrele(olddquot1);
    xfs_qm_dqrele(olddquot2);
    xfs_qm_dqrele(udqp);
    xfs_qm_dqrele(gdqp);

    if (error)
        return XFS_ERROR(error);

    /*
     * XXX(hch): Updating the ACL entries is not atomic vs the i_mode
     *       update.  We could avoid this with linked transactions
     *       and passing down the transaction pointer all the way
     *       to attr_set.  No previous user of the generic
     *       Posix ACL code seems to care about this issue either.
     */
    if ((mask & ATTR_MODE) && !(flags & XFS_ATTR_NOACL)) {
        error = -xfs_acl_chmod(inode);
        if (error)
            return XFS_ERROR(error);
    }

    return 0;

out_trans_cancel:
    xfs_trans_cancel(tp, 0);
    xfs_iunlock(ip, XFS_ILOCK_EXCL);
out_dqrele:
    xfs_qm_dqrele(udqp);
    xfs_qm_dqrele(gdqp);
    return error;
}

/*
 * Truncate file.  Must have write permission and not be a directory.
 */
int
xfs_setattr_size(
    struct xfs_inode    *ip,
    struct iattr        *iattr,
    int         flags)
{
    struct xfs_mount    *mp = ip->i_mount;
    struct inode        *inode = VFS_I(ip);
    int         mask = iattr->ia_valid;
    xfs_off_t       oldsize, newsize;
    struct xfs_trans    *tp;
    int         error;
    uint            lock_flags = 0;
    uint            commit_flags = 0;

    trace_xfs_setattr(ip);

    if (mp->m_flags & XFS_MOUNT_RDONLY)
        return XFS_ERROR(EROFS);

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

    error = -inode_change_ok(inode, iattr);
    if (error)
        return XFS_ERROR(error);

    ASSERT(S_ISREG(ip->i_d.di_mode));
    ASSERT((mask & (ATTR_MODE|ATTR_UID|ATTR_GID|ATTR_ATIME|ATTR_ATIME_SET|
            ATTR_MTIME_SET|ATTR_KILL_SUID|ATTR_KILL_SGID|
            ATTR_KILL_PRIV|ATTR_TIMES_SET)) == 0);

    if (!(flags & XFS_ATTR_NOLOCK)) {
        lock_flags |= XFS_IOLOCK_EXCL;
        xfs_ilock(ip, lock_flags);
    }

    oldsize = inode->i_size;
    newsize = iattr->ia_size;

    /*
     * Short circuit the truncate case for zero length files.
     */
    if (newsize == 0 && oldsize == 0 && ip->i_d.di_nextents == 0) {
        if (!(mask & (ATTR_CTIME|ATTR_MTIME)))
            goto out_unlock;

        /*
         * Use the regular setattr path to update the timestamps.
         */
        xfs_iunlock(ip, lock_flags);
        iattr->ia_valid &= ~ATTR_SIZE;
        return xfs_setattr_nonsize(ip, iattr, 0);
    }

    /*
     * Make sure that the dquots are attached to the inode.
     */
    error = xfs_qm_dqattach(ip, 0);
    if (error)
        goto out_unlock;

    /*
     * Now we can make the changes.  Before we join the inode to the
     * transaction, take care of the part of the truncation that must be
     * done without the inode lock.  This needs to be done before joining
     * the inode to the transaction, because the inode cannot be unlocked
     * once it is a part of the transaction.
     */
    if (newsize > oldsize) {
        /*
         * Do the first part of growing a file: zero any data in the
         * last block that is beyond the old EOF.  We need to do this
         * before the inode is joined to the transaction to modify
         * i_size.
         */
        error = xfs_zero_eof(ip, newsize, oldsize);
        if (error)
            goto out_unlock;
    }

    /*
     * We are going to log the inode size change in this transaction so
     * any previous writes that are beyond the on disk EOF and the new
     * EOF that have not been written out need to be written here.  If we
     * do not write the data out, we expose ourselves to the null files
     * problem.
     *
     * Only flush from the on disk size to the smaller of the in memory
     * file size or the new size as that's the range we really care about
     * here and prevents waiting for other data not within the range we
     * care about here.
     */
    if (oldsize != ip->i_d.di_size && newsize > ip->i_d.di_size) {
        error = xfs_flush_pages(ip, ip->i_d.di_size, newsize, 0,
                    FI_NONE);
        if (error)
            goto out_unlock;
    }

    /*
     * Wait for all direct I/O to complete.
     */
    inode_dio_wait(inode);

    error = -block_truncate_page(inode->i_mapping, newsize, xfs_get_blocks);
    if (error)
        goto out_unlock;

    tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_SIZE);
    error = xfs_trans_reserve(tp, 0, XFS_ITRUNCATE_LOG_RES(mp), 0,
                 XFS_TRANS_PERM_LOG_RES,
                 XFS_ITRUNCATE_LOG_COUNT);
    if (error)
        goto out_trans_cancel;

    truncate_setsize(inode, newsize);

    commit_flags = XFS_TRANS_RELEASE_LOG_RES;
    lock_flags |= XFS_ILOCK_EXCL;

    xfs_ilock(ip, XFS_ILOCK_EXCL);

    xfs_trans_ijoin(tp, ip, 0);

    /*
     * Only change the c/mtime if we are changing the size or we are
     * explicitly asked to change it.  This handles the semantic difference
     * between truncate() and ftruncate() as implemented in the VFS.
     *
     * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
     * special case where we need to update the times despite not having
     * these flags set.  For all other operations the VFS set these flags
     * explicitly if it wants a timestamp update.
     */
    if (newsize != oldsize && (!(mask & (ATTR_CTIME | ATTR_MTIME)))) {
        iattr->ia_ctime = iattr->ia_mtime =
            current_fs_time(inode->i_sb);
        mask |= ATTR_CTIME | ATTR_MTIME;
    }

    /*
     * The first thing we do is set the size to new_size permanently on
     * disk.  This way we don't have to worry about anyone ever being able
     * to look at the data being freed even in the face of a crash.
     * What we're getting around here is the case where we free a block, it
     * is allocated to another file, it is written to, and then we crash.
     * If the new data gets written to the file but the log buffers
     * containing the free and reallocation don't, then we'd end up with
     * garbage in the blocks being freed.  As long as we make the new size
     * permanent before actually freeing any blocks it doesn't matter if
     * they get written to.
     */
    ip->i_d.di_size = newsize;
    xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

    if (newsize <= oldsize) {
        error = xfs_itruncate_extents(&tp, ip, XFS_DATA_FORK, newsize);
        if (error)
            goto out_trans_abort;

        /*
         * Truncated "down", so we're removing references to old data
         * here - if we delay flushing for a long time, we expose
         * ourselves unduly to the notorious NULL files problem.  So,
         * we mark this inode and flush it when the file is closed,
         * and do not wait the usual (long) time for writeout.
         */
        xfs_iflags_set(ip, XFS_ITRUNCATED);
    }

    if (mask & ATTR_CTIME) {
        inode->i_ctime = iattr->ia_ctime;
        ip->i_d.di_ctime.t_sec = iattr->ia_ctime.tv_sec;
        ip->i_d.di_ctime.t_nsec = iattr->ia_ctime.tv_nsec;
    }
    if (mask & ATTR_MTIME) {
        inode->i_mtime = iattr->ia_mtime;
        ip->i_d.di_mtime.t_sec = iattr->ia_mtime.tv_sec;
        ip->i_d.di_mtime.t_nsec = iattr->ia_mtime.tv_nsec;
    }

    xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

    XFS_STATS_INC(xs_ig_attrchg);

    if (mp->m_flags & XFS_MOUNT_WSYNC)
        xfs_trans_set_sync(tp);

    error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
out_unlock:
    if (lock_flags)
        xfs_iunlock(ip, lock_flags);
    return error;

out_trans_abort:
    commit_flags |= XFS_TRANS_ABORT;
out_trans_cancel:
    xfs_trans_cancel(tp, commit_flags);
    goto out_unlock;
}

STATIC int
xfs_vn_setattr(
    struct dentry   *dentry,
    struct iattr    *iattr)
{
    if (iattr->ia_valid & ATTR_SIZE)
        return -xfs_setattr_size(XFS_I(dentry->d_inode), iattr, 0);
    return -xfs_setattr_nonsize(XFS_I(dentry->d_inode), iattr, 0);
}

STATIC int
xfs_vn_update_time(
    struct inode        *inode,
    struct timespec     *now,
    int         flags)
{
    struct xfs_inode    *ip = XFS_I(inode);
    struct xfs_mount    *mp = ip->i_mount;
    struct xfs_trans    *tp;
    int         error;

    trace_xfs_update_time(ip);

    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);
        return -error;
    }

    xfs_ilock(ip, XFS_ILOCK_EXCL);
    if (flags & S_CTIME) {
        inode->i_ctime = *now;
        ip->i_d.di_ctime.t_sec = (__int32_t)now->tv_sec;
        ip->i_d.di_ctime.t_nsec = (__int32_t)now->tv_nsec;
    }
    if (flags & S_MTIME) {
        inode->i_mtime = *now;
        ip->i_d.di_mtime.t_sec = (__int32_t)now->tv_sec;
        ip->i_d.di_mtime.t_nsec = (__int32_t)now->tv_nsec;
    }
    if (flags & S_ATIME) {
        inode->i_atime = *now;
        ip->i_d.di_atime.t_sec = (__int32_t)now->tv_sec;
        ip->i_d.di_atime.t_nsec = (__int32_t)now->tv_nsec;
    }
    xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
    xfs_trans_log_inode(tp, ip, XFS_ILOG_TIMESTAMP);
    return -xfs_trans_commit(tp, 0);
}

#define XFS_FIEMAP_FLAGS    (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)

/*
 * Call fiemap helper to fill in user data.
 * Returns positive errors to xfs_getbmap.
 */
STATIC int
xfs_fiemap_format(
    void            **arg,
    struct getbmapx     *bmv,
    int         *full)
{
    int         error;
    struct fiemap_extent_info *fieinfo = *arg;
    u32         fiemap_flags = 0;
    u64         logical, physical, length;

    /* Do nothing for a hole */
    if (bmv->bmv_block == -1LL)
        return 0;

    logical = BBTOB(bmv->bmv_offset);
    physical = BBTOB(bmv->bmv_block);
    length = BBTOB(bmv->bmv_length);

    if (bmv->bmv_oflags & BMV_OF_PREALLOC)
        fiemap_flags |= FIEMAP_EXTENT_UNWRITTEN;
    else if (bmv->bmv_oflags & BMV_OF_DELALLOC) {
        fiemap_flags |= FIEMAP_EXTENT_DELALLOC;
        physical = 0;   /* no block yet */
    }
    if (bmv->bmv_oflags & BMV_OF_LAST)
        fiemap_flags |= FIEMAP_EXTENT_LAST;

    error = fiemap_fill_next_extent(fieinfo, logical, physical,
                    length, fiemap_flags);
    if (error > 0) {
        error = 0;
        *full = 1;  /* user array now full */
    }

    return -error;
}

STATIC int
xfs_vn_fiemap(
    struct inode        *inode,
    struct fiemap_extent_info *fieinfo,
    u64         start,
    u64         length)
{
    xfs_inode_t     *ip = XFS_I(inode);
    struct getbmapx     bm;
    int         error;

    error = fiemap_check_flags(fieinfo, XFS_FIEMAP_FLAGS);
    if (error)
        return error;

    /* Set up bmap header for xfs internal routine */
    bm.bmv_offset = BTOBB(start);
    /* Special case for whole file */
    if (length == FIEMAP_MAX_OFFSET)
        bm.bmv_length = -1LL;
    else
        bm.bmv_length = BTOBB(length);

    /* We add one because in getbmap world count includes the header */
    bm.bmv_count = !fieinfo->fi_extents_max ? MAXEXTNUM :
                    fieinfo->fi_extents_max + 1;
    bm.bmv_count = min_t(__s32, bm.bmv_count,
                 (PAGE_SIZE * 16 / sizeof(struct getbmapx)));
    bm.bmv_iflags = BMV_IF_PREALLOC | BMV_IF_NO_HOLES;
    if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR)
        bm.bmv_iflags |= BMV_IF_ATTRFORK;
    if (!(fieinfo->fi_flags & FIEMAP_FLAG_SYNC))
        bm.bmv_iflags |= BMV_IF_DELALLOC;

    error = xfs_getbmap(ip, &bm, xfs_fiemap_format, fieinfo);
    if (error)
        return -error;

    return 0;
}

static const struct inode_operations xfs_inode_operations = {
    .get_acl        = xfs_get_acl,
    .getattr        = xfs_vn_getattr,
    .setattr        = xfs_vn_setattr,
    .setxattr       = generic_setxattr,
    .getxattr       = generic_getxattr,
    .removexattr        = generic_removexattr,
    .listxattr      = xfs_vn_listxattr,
    .fiemap         = xfs_vn_fiemap,
    .update_time        = xfs_vn_update_time,
};

static const struct inode_operations xfs_dir_inode_operations = {
    .create         = xfs_vn_create,
    .lookup         = xfs_vn_lookup,
    .link           = xfs_vn_link,
    .unlink         = xfs_vn_unlink,
    .symlink        = xfs_vn_symlink,
    .mkdir          = xfs_vn_mkdir,
    /*
     * Yes, XFS uses the same method for rmdir and unlink.
     *
     * There are some subtile differences deeper in the code,
     * but we use S_ISDIR to check for those.
     */
    .rmdir          = xfs_vn_unlink,
    .mknod          = xfs_vn_mknod,
    .rename         = xfs_vn_rename,
    .get_acl        = xfs_get_acl,
    .getattr        = xfs_vn_getattr,
    .setattr        = xfs_vn_setattr,
    .setxattr       = generic_setxattr,
    .getxattr       = generic_getxattr,
    .removexattr        = generic_removexattr,
    .listxattr      = xfs_vn_listxattr,
    .update_time        = xfs_vn_update_time,
};

static const struct inode_operations xfs_dir_ci_inode_operations = {
    .create         = xfs_vn_create,
    .lookup         = xfs_vn_ci_lookup,
    .link           = xfs_vn_link,
    .unlink         = xfs_vn_unlink,
    .symlink        = xfs_vn_symlink,
    .mkdir          = xfs_vn_mkdir,
    /*
     * Yes, XFS uses the same method for rmdir and unlink.
     *
     * There are some subtile differences deeper in the code,
     * but we use S_ISDIR to check for those.
     */
    .rmdir          = xfs_vn_unlink,
    .mknod          = xfs_vn_mknod,
    .rename         = xfs_vn_rename,
    .get_acl        = xfs_get_acl,
    .getattr        = xfs_vn_getattr,
    .setattr        = xfs_vn_setattr,
    .setxattr       = generic_setxattr,
    .getxattr       = generic_getxattr,
    .removexattr        = generic_removexattr,
    .listxattr      = xfs_vn_listxattr,
    .update_time        = xfs_vn_update_time,
};

static const struct inode_operations xfs_symlink_inode_operations = {
    .readlink       = generic_readlink,
    .follow_link        = xfs_vn_follow_link,
    .put_link       = xfs_vn_put_link,
    .get_acl        = xfs_get_acl,
    .getattr        = xfs_vn_getattr,
    .setattr        = xfs_vn_setattr,
    .setxattr       = generic_setxattr,
    .getxattr       = generic_getxattr,
    .removexattr        = generic_removexattr,
    .listxattr      = xfs_vn_listxattr,
    .update_time        = xfs_vn_update_time,
};

STATIC void
xfs_diflags_to_iflags(
    struct inode        *inode,
    struct xfs_inode    *ip)
{
    if (ip->i_d.di_flags & XFS_DIFLAG_IMMUTABLE)
        inode->i_flags |= S_IMMUTABLE;
    else
        inode->i_flags &= ~S_IMMUTABLE;
    if (ip->i_d.di_flags & XFS_DIFLAG_APPEND)
        inode->i_flags |= S_APPEND;
    else
        inode->i_flags &= ~S_APPEND;
    if (ip->i_d.di_flags & XFS_DIFLAG_SYNC)
        inode->i_flags |= S_SYNC;
    else
        inode->i_flags &= ~S_SYNC;
    if (ip->i_d.di_flags & XFS_DIFLAG_NOATIME)
        inode->i_flags |= S_NOATIME;
    else
        inode->i_flags &= ~S_NOATIME;
}

/*
 * Initialize the Linux inode, set up the operation vectors and
 * unlock the inode.
 *
 * When reading existing inodes from disk this is called directly
 * from xfs_iget, when creating a new inode it is called from
 * xfs_ialloc after setting up the inode.
 *
 * We are always called with an uninitialised linux inode here.
 * We need to initialise the necessary fields and take a reference
 * on it.
 */
void
xfs_setup_inode(
    struct xfs_inode    *ip)
{
    struct inode        *inode = &ip->i_vnode;

    inode->i_ino = ip->i_ino;
    inode->i_state = I_NEW;

    inode_sb_list_add(inode);
    /* make the inode look hashed for the writeback code */
    hlist_add_fake(&inode->i_hash);

    inode->i_mode   = ip->i_d.di_mode;
    set_nlink(inode, ip->i_d.di_nlink);
    inode->i_uid    = ip->i_d.di_uid;
    inode->i_gid    = ip->i_d.di_gid;

    switch (inode->i_mode & S_IFMT) {
    case S_IFBLK:
    case S_IFCHR:
        inode->i_rdev =
            MKDEV(sysv_major(ip->i_df.if_u2.if_rdev) & 0x1ff,
                  sysv_minor(ip->i_df.if_u2.if_rdev));
        break;
    default:
        inode->i_rdev = 0;
        break;
    }

    inode->i_generation = ip->i_d.di_gen;
    i_size_write(inode, ip->i_d.di_size);
    inode->i_atime.tv_sec   = ip->i_d.di_atime.t_sec;
    inode->i_atime.tv_nsec  = ip->i_d.di_atime.t_nsec;
    inode->i_mtime.tv_sec   = ip->i_d.di_mtime.t_sec;
    inode->i_mtime.tv_nsec  = ip->i_d.di_mtime.t_nsec;
    inode->i_ctime.tv_sec   = ip->i_d.di_ctime.t_sec;
    inode->i_ctime.tv_nsec  = ip->i_d.di_ctime.t_nsec;
    xfs_diflags_to_iflags(inode, ip);

    switch (inode->i_mode & S_IFMT) {
    case S_IFREG:
        inode->i_op = &xfs_inode_operations;
        inode->i_fop = &xfs_file_operations;
        inode->i_mapping->a_ops = &xfs_address_space_operations;
        break;
    case S_IFDIR:
        if (xfs_sb_version_hasasciici(&XFS_M(inode->i_sb)->m_sb))
            inode->i_op = &xfs_dir_ci_inode_operations;
        else
            inode->i_op = &xfs_dir_inode_operations;
        inode->i_fop = &xfs_dir_file_operations;
        break;
    case S_IFLNK:
        inode->i_op = &xfs_symlink_inode_operations;
        if (!(ip->i_df.if_flags & XFS_IFINLINE))
            inode->i_mapping->a_ops = &xfs_address_space_operations;
        break;
    default:
        inode->i_op = &xfs_inode_operations;
        init_special_inode(inode, inode->i_mode, inode->i_rdev);
        break;
    }

    /*
     * If there is no attribute fork no ACL can exist on this inode,
     * and it can't have any file capabilities attached to it either.
     */
    if (!XFS_IFORK_Q(ip)) {
        inode_has_no_xattr(inode);
        cache_no_acl(inode);
    }

    xfs_iflags_clear(ip, XFS_INEW);
    barrier();

    unlock_new_inode(inode);
}