inode.c

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/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2011 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/namei.h>
#include <linux/mm.h>
#include <linux/xattr.h>
#include <linux/posix_acl.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.h>
#include <linux/fiemap.h>
#include <linux/security.h>
#include <asm/uaccess.h>

#include "gfs2.h"
#include "incore.h"
#include "acl.h"
#include "bmap.h"
#include "dir.h"
#include "xattr.h"
#include "glock.h"
#include "inode.h"
#include "meta_io.h"
#include "quota.h"
#include "rgrp.h"
#include "trans.h"
#include "util.h"
#include "super.h"
#include "glops.h"

struct gfs2_skip_data {
    u64 no_addr;
    int skipped;
    int non_block;
};

static int iget_test(struct inode *inode, void *opaque)
{
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_skip_data *data = opaque;

    if (ip->i_no_addr == data->no_addr) {
        if (data->non_block &&
            inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
            data->skipped = 1;
            return 0;
        }
        return 1;
    }
    return 0;
}

static int iget_set(struct inode *inode, void *opaque)
{
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_skip_data *data = opaque;

    if (data->skipped)
        return -ENOENT;
    inode->i_ino = (unsigned long)(data->no_addr);
    ip->i_no_addr = data->no_addr;
    return 0;
}

struct inode *gfs2_ilookup(struct super_block *sb, u64 no_addr, int non_block)
{
    unsigned long hash = (unsigned long)no_addr;
    struct gfs2_skip_data data;

    data.no_addr = no_addr;
    data.skipped = 0;
    data.non_block = non_block;
    return ilookup5(sb, hash, iget_test, &data);
}

static struct inode *gfs2_iget(struct super_block *sb, u64 no_addr,
                   int non_block)
{
    struct gfs2_skip_data data;
    unsigned long hash = (unsigned long)no_addr;

    data.no_addr = no_addr;
    data.skipped = 0;
    data.non_block = non_block;
    return iget5_locked(sb, hash, iget_test, iget_set, &data);
}

static void gfs2_set_iop(struct inode *inode)
{
    struct gfs2_sbd *sdp = GFS2_SB(inode);
    umode_t mode = inode->i_mode;

    if (S_ISREG(mode)) {
        inode->i_op = &gfs2_file_iops;
        if (gfs2_localflocks(sdp))
            inode->i_fop = &gfs2_file_fops_nolock;
        else
            inode->i_fop = &gfs2_file_fops;
    } else if (S_ISDIR(mode)) {
        inode->i_op = &gfs2_dir_iops;
        if (gfs2_localflocks(sdp))
            inode->i_fop = &gfs2_dir_fops_nolock;
        else
            inode->i_fop = &gfs2_dir_fops;
    } else if (S_ISLNK(mode)) {
        inode->i_op = &gfs2_symlink_iops;
    } else {
        inode->i_op = &gfs2_file_iops;
        init_special_inode(inode, inode->i_mode, inode->i_rdev);
    }
}

struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned int type,
                u64 no_addr, u64 no_formal_ino, int non_block)
{
    struct inode *inode;
    struct gfs2_inode *ip;
    struct gfs2_glock *io_gl = NULL;
    int error;

    inode = gfs2_iget(sb, no_addr, non_block);
    ip = GFS2_I(inode);

    if (!inode)
        return ERR_PTR(-ENOBUFS);

    if (inode->i_state & I_NEW) {
        struct gfs2_sbd *sdp = GFS2_SB(inode);
        ip->i_no_formal_ino = no_formal_ino;

        error = gfs2_glock_get(sdp, no_addr, &gfs2_inode_glops, CREATE, &ip->i_gl);
        if (unlikely(error))
            goto fail;
        ip->i_gl->gl_object = ip;

        error = gfs2_glock_get(sdp, no_addr, &gfs2_iopen_glops, CREATE, &io_gl);
        if (unlikely(error))
            goto fail_put;

        set_bit(GIF_INVALID, &ip->i_flags);
        error = gfs2_glock_nq_init(io_gl, LM_ST_SHARED, GL_EXACT, &ip->i_iopen_gh);
        if (unlikely(error))
            goto fail_iopen;

        ip->i_iopen_gh.gh_gl->gl_object = ip;
        gfs2_glock_put(io_gl);
        io_gl = NULL;

        if (type == DT_UNKNOWN) {
            /* Inode glock must be locked already */
            error = gfs2_inode_refresh(GFS2_I(inode));
            if (error)
                goto fail_refresh;
        } else {
            inode->i_mode = DT2IF(type);
        }

        gfs2_set_iop(inode);
        unlock_new_inode(inode);
    }

    return inode;

fail_refresh:
    ip->i_iopen_gh.gh_gl->gl_object = NULL;
    gfs2_glock_dq_uninit(&ip->i_iopen_gh);
fail_iopen:
    if (io_gl)
        gfs2_glock_put(io_gl);
fail_put:
    ip->i_gl->gl_object = NULL;
    gfs2_glock_put(ip->i_gl);
fail:
    iget_failed(inode);
    return ERR_PTR(error);
}

struct inode *gfs2_lookup_by_inum(struct gfs2_sbd *sdp, u64 no_addr,
                  u64 *no_formal_ino, unsigned int blktype)
{
    struct super_block *sb = sdp->sd_vfs;
    struct gfs2_holder i_gh;
    struct inode *inode = NULL;
    int error;

    /* Must not read in block until block type is verified */
    error = gfs2_glock_nq_num(sdp, no_addr, &gfs2_inode_glops,
                  LM_ST_EXCLUSIVE, GL_SKIP, &i_gh);
    if (error)
        return ERR_PTR(error);

    error = gfs2_check_blk_type(sdp, no_addr, blktype);
    if (error)
        goto fail;

    inode = gfs2_inode_lookup(sb, DT_UNKNOWN, no_addr, 0, 1);
    if (IS_ERR(inode))
        goto fail;

    /* Two extra checks for NFS only */
    if (no_formal_ino) {
        error = -ESTALE;
        if (GFS2_I(inode)->i_no_formal_ino != *no_formal_ino)
            goto fail_iput;

        error = -EIO;
        if (GFS2_I(inode)->i_diskflags & GFS2_DIF_SYSTEM)
            goto fail_iput;

        error = 0;
    }

fail:
    gfs2_glock_dq_uninit(&i_gh);
    return error ? ERR_PTR(error) : inode;
fail_iput:
    iput(inode);
    goto fail;
}


struct inode *gfs2_lookup_simple(struct inode *dip, const char *name)
{
    struct qstr qstr;
    struct inode *inode;
    gfs2_str2qstr(&qstr, name);
    inode = gfs2_lookupi(dip, &qstr, 1);
    /* gfs2_lookupi has inconsistent callers: vfs
     * related routines expect NULL for no entry found,
     * gfs2_lookup_simple callers expect ENOENT
     * and do not check for NULL.
     */
    if (inode == NULL)
        return ERR_PTR(-ENOENT);
    else
        return inode;
}


struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
               int is_root)
{
    struct super_block *sb = dir->i_sb;
    struct gfs2_inode *dip = GFS2_I(dir);
    struct gfs2_holder d_gh;
    int error = 0;
    struct inode *inode = NULL;
    int unlock = 0;

    if (!name->len || name->len > GFS2_FNAMESIZE)
        return ERR_PTR(-ENAMETOOLONG);

    if ((name->len == 1 && memcmp(name->name, ".", 1) == 0) ||
        (name->len == 2 && memcmp(name->name, "..", 2) == 0 &&
         dir == sb->s_root->d_inode)) {
        igrab(dir);
        return dir;
    }

    if (gfs2_glock_is_locked_by_me(dip->i_gl) == NULL) {
        error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
        if (error)
            return ERR_PTR(error);
        unlock = 1;
    }

    if (!is_root) {
        error = gfs2_permission(dir, MAY_EXEC);
        if (error)
            goto out;
    }

    inode = gfs2_dir_search(dir, name);
    if (IS_ERR(inode))
        error = PTR_ERR(inode);
out:
    if (unlock)
        gfs2_glock_dq_uninit(&d_gh);
    if (error == -ENOENT)
        return NULL;
    return inode ? inode : ERR_PTR(error);
}

static int create_ok(struct gfs2_inode *dip, const struct qstr *name,
             umode_t mode)
{
    int error;

    error = gfs2_permission(&dip->i_inode, MAY_WRITE | MAY_EXEC);
    if (error)
        return error;

    /*  Don't create entries in an unlinked directory  */
    if (!dip->i_inode.i_nlink)
        return -ENOENT;

    error = gfs2_dir_check(&dip->i_inode, name, NULL);
    switch (error) {
    case -ENOENT:
        error = 0;
        break;
    case 0:
        return -EEXIST;
    default:
        return error;
    }

    if (dip->i_entries == (u32)-1)
        return -EFBIG;
    if (S_ISDIR(mode) && dip->i_inode.i_nlink == (u32)-1)
        return -EMLINK;

    return 0;
}

static void munge_mode_uid_gid(struct gfs2_inode *dip, umode_t *mode,
                   unsigned int *uid, unsigned int *gid)
{
    if (GFS2_SB(&dip->i_inode)->sd_args.ar_suiddir &&
        (dip->i_inode.i_mode & S_ISUID) && dip->i_inode.i_uid) {
        if (S_ISDIR(*mode))
            *mode |= S_ISUID;
        else if (dip->i_inode.i_uid != current_fsuid())
            *mode &= ~07111;
        *uid = dip->i_inode.i_uid;
    } else
        *uid = current_fsuid();

    if (dip->i_inode.i_mode & S_ISGID) {
        if (S_ISDIR(*mode))
            *mode |= S_ISGID;
        *gid = dip->i_inode.i_gid;
    } else
        *gid = current_fsgid();
}

static int alloc_dinode(struct gfs2_inode *dip, u64 *no_addr, u64 *generation)
{
    struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
    int error;
    int dblocks = 1;

    error = gfs2_inplace_reserve(dip, RES_DINODE);
    if (error)
        goto out;

    error = gfs2_trans_begin(sdp, RES_RG_BIT + RES_STATFS, 0);
    if (error)
        goto out_ipreserv;

    error = gfs2_alloc_blocks(dip, no_addr, &dblocks, 1, generation);

    gfs2_trans_end(sdp);

out_ipreserv:
    gfs2_inplace_release(dip);
out:
    return error;
}

static void gfs2_init_dir(struct buffer_head *dibh,
              const struct gfs2_inode *parent)
{
    struct gfs2_dinode *di = (struct gfs2_dinode *)dibh->b_data;
    struct gfs2_dirent *dent = (struct gfs2_dirent *)(di+1);

    gfs2_qstr2dirent(&gfs2_qdot, GFS2_DIRENT_SIZE(gfs2_qdot.len), dent);
    dent->de_inum = di->di_num; /* already GFS2 endian */
    dent->de_type = cpu_to_be16(DT_DIR);

    dent = (struct gfs2_dirent *)((char*)dent + GFS2_DIRENT_SIZE(1));
    gfs2_qstr2dirent(&gfs2_qdotdot, dibh->b_size - GFS2_DIRENT_SIZE(1) - sizeof(struct gfs2_dinode), dent);
    gfs2_inum_out(parent, dent);
    dent->de_type = cpu_to_be16(DT_DIR);
    
}

static void init_dinode(struct gfs2_inode *dip, struct gfs2_glock *gl,
            const struct gfs2_inum_host *inum, umode_t mode,
            unsigned int uid, unsigned int gid,
            const u64 *generation, dev_t dev, const char *symname,
            unsigned size, struct buffer_head **bhp)
{
    struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
    struct gfs2_dinode *di;
    struct buffer_head *dibh;
    struct timespec tv = CURRENT_TIME;

    dibh = gfs2_meta_new(gl, inum->no_addr);
    gfs2_trans_add_bh(gl, dibh, 1);
    gfs2_metatype_set(dibh, GFS2_METATYPE_DI, GFS2_FORMAT_DI);
    gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
    di = (struct gfs2_dinode *)dibh->b_data;

    di->di_num.no_formal_ino = cpu_to_be64(inum->no_formal_ino);
    di->di_num.no_addr = cpu_to_be64(inum->no_addr);
    di->di_mode = cpu_to_be32(mode);
    di->di_uid = cpu_to_be32(uid);
    di->di_gid = cpu_to_be32(gid);
    di->di_nlink = 0;
    di->di_size = cpu_to_be64(size);
    di->di_blocks = cpu_to_be64(1);
    di->di_atime = di->di_mtime = di->di_ctime = cpu_to_be64(tv.tv_sec);
    di->di_major = cpu_to_be32(MAJOR(dev));
    di->di_minor = cpu_to_be32(MINOR(dev));
    di->di_goal_meta = di->di_goal_data = cpu_to_be64(inum->no_addr);
    di->di_generation = cpu_to_be64(*generation);
    di->di_flags = 0;
    di->__pad1 = 0;
    di->di_payload_format = cpu_to_be32(S_ISDIR(mode) ? GFS2_FORMAT_DE : 0);
    di->di_height = 0;
    di->__pad2 = 0;
    di->__pad3 = 0;
    di->di_depth = 0;
    di->di_entries = 0;
    memset(&di->__pad4, 0, sizeof(di->__pad4));
    di->di_eattr = 0;
    di->di_atime_nsec = cpu_to_be32(tv.tv_nsec);
    di->di_mtime_nsec = cpu_to_be32(tv.tv_nsec);
    di->di_ctime_nsec = cpu_to_be32(tv.tv_nsec);
    memset(&di->di_reserved, 0, sizeof(di->di_reserved));

    switch(mode & S_IFMT) { 
    case S_IFREG:
        if ((dip->i_diskflags & GFS2_DIF_INHERIT_JDATA) ||
            gfs2_tune_get(sdp, gt_new_files_jdata))
            di->di_flags |= cpu_to_be32(GFS2_DIF_JDATA);
        break;
    case S_IFDIR:
        di->di_flags |= cpu_to_be32(dip->i_diskflags &
                        GFS2_DIF_INHERIT_JDATA);
        di->di_flags |= cpu_to_be32(GFS2_DIF_JDATA);
        di->di_size = cpu_to_be64(sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode));
        di->di_entries = cpu_to_be32(2);
        gfs2_init_dir(dibh, dip);
        break;
    case S_IFLNK:
        memcpy(dibh->b_data + sizeof(struct gfs2_dinode), symname, size);
        break;
    }

    set_buffer_uptodate(dibh);

    *bhp = dibh;
}

static int make_dinode(struct gfs2_inode *dip, struct gfs2_glock *gl,
               umode_t mode, const struct gfs2_inum_host *inum,
               const u64 *generation, dev_t dev, const char *symname,
               unsigned int size, struct buffer_head **bhp)
{
    struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
    unsigned int uid, gid;
    int error;

    munge_mode_uid_gid(dip, &mode, &uid, &gid);
    error = gfs2_rindex_update(sdp);
    if (error)
        return error;

    error = gfs2_quota_lock(dip, uid, gid);
    if (error)
        return error;

    error = gfs2_quota_check(dip, uid, gid);
    if (error)
        goto out_quota;

    error = gfs2_trans_begin(sdp, RES_DINODE + RES_QUOTA, 0);
    if (error)
        goto out_quota;

    init_dinode(dip, gl, inum, mode, uid, gid, generation, dev, symname, size, bhp);
    gfs2_quota_change(dip, +1, uid, gid);
    gfs2_trans_end(sdp);

out_quota:
    gfs2_quota_unlock(dip);
    return error;
}

static int link_dinode(struct gfs2_inode *dip, const struct qstr *name,
               struct gfs2_inode *ip)
{
    struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
    int alloc_required;
    struct buffer_head *dibh;
    int error;

    error = gfs2_rindex_update(sdp);
    if (error)
        return error;

    error = gfs2_quota_lock(dip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
    if (error)
        goto fail;

    error = alloc_required = gfs2_diradd_alloc_required(&dip->i_inode, name);
    if (alloc_required < 0)
        goto fail_quota_locks;
    if (alloc_required) {
        error = gfs2_quota_check(dip, dip->i_inode.i_uid, dip->i_inode.i_gid);
        if (error)
            goto fail_quota_locks;

        error = gfs2_inplace_reserve(dip, sdp->sd_max_dirres);
        if (error)
            goto fail_quota_locks;

        error = gfs2_trans_begin(sdp, sdp->sd_max_dirres +
                     dip->i_rgd->rd_length +
                     2 * RES_DINODE +
                     RES_STATFS + RES_QUOTA, 0);
        if (error)
            goto fail_ipreserv;
    } else {
        error = gfs2_trans_begin(sdp, RES_LEAF + 2 * RES_DINODE, 0);
        if (error)
            goto fail_quota_locks;
    }

    error = gfs2_dir_add(&dip->i_inode, name, ip);
    if (error)
        goto fail_end_trans;

    error = gfs2_meta_inode_buffer(ip, &dibh);
    if (error)
        goto fail_end_trans;
    set_nlink(&ip->i_inode, S_ISDIR(ip->i_inode.i_mode) ? 2 : 1);
    gfs2_trans_add_bh(ip->i_gl, dibh, 1);
    gfs2_dinode_out(ip, dibh->b_data);
    brelse(dibh);
    return 0;

fail_end_trans:
    gfs2_trans_end(sdp);

fail_ipreserv:
    if (alloc_required)
        gfs2_inplace_release(dip);

fail_quota_locks:
    gfs2_quota_unlock(dip);

fail:
    return error;
}

static int gfs2_initxattrs(struct inode *inode, const struct xattr *xattr_array,
            void *fs_info)
{
    const struct xattr *xattr;
    int err = 0;

    for (xattr = xattr_array; xattr->name != NULL; xattr++) {
        err = __gfs2_xattr_set(inode, xattr->name, xattr->value,
                       xattr->value_len, 0,
                       GFS2_EATYPE_SECURITY);
        if (err < 0)
            break;
    }
    return err;
}

static int gfs2_security_init(struct gfs2_inode *dip, struct gfs2_inode *ip,
                  const struct qstr *qstr)
{
    return security_inode_init_security(&ip->i_inode, &dip->i_inode, qstr,
                        &gfs2_initxattrs, NULL);
}

static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
                 umode_t mode, dev_t dev, const char *symname,
                 unsigned int size, int excl)
{
    const struct qstr *name = &dentry->d_name;
    struct gfs2_holder ghs[2];
    struct inode *inode = NULL;
    struct gfs2_inode *dip = GFS2_I(dir), *ip;
    struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
    struct gfs2_inum_host inum = { .no_addr = 0, .no_formal_ino = 0 };
    int error;
    u64 generation;
    struct buffer_head *bh = NULL;

    if (!name->len || name->len > GFS2_FNAMESIZE)
        return -ENAMETOOLONG;

    /* We need a reservation to allocate the new dinode block. The
       directory ip temporarily points to the reservation, but this is
       being done to get a set of contiguous blocks for the new dinode.
       Since this is a create, we don't have a sizehint yet, so it will
       have to use the minimum reservation size. */
    error = gfs2_rs_alloc(dip);
    if (error)
        return error;

    error = gfs2_glock_nq_init(dip->i_gl, LM_ST_EXCLUSIVE, 0, ghs);
    if (error)
        goto fail;

    error = create_ok(dip, name, mode);
    if ((error == -EEXIST) && S_ISREG(mode) && !excl) {
        inode = gfs2_lookupi(dir, &dentry->d_name, 0);
        gfs2_glock_dq_uninit(ghs);
        d_instantiate(dentry, inode);
        return IS_ERR(inode) ? PTR_ERR(inode) : 0;
    }
    if (error)
        goto fail_gunlock;

    error = alloc_dinode(dip, &inum.no_addr, &generation);
    if (error)
        goto fail_gunlock;
    inum.no_formal_ino = generation;

    error = gfs2_glock_nq_num(sdp, inum.no_addr, &gfs2_inode_glops,
                  LM_ST_EXCLUSIVE, GL_SKIP, ghs + 1);
    if (error)
        goto fail_gunlock;

    error = make_dinode(dip, ghs[1].gh_gl, mode, &inum, &generation, dev, symname, size, &bh);
    if (error)
        goto fail_gunlock2;

    inode = gfs2_inode_lookup(dir->i_sb, IF2DT(mode), inum.no_addr,
                  inum.no_formal_ino, 0);
    if (IS_ERR(inode))
        goto fail_gunlock2;

    ip = GFS2_I(inode);
    error = gfs2_inode_refresh(ip);
    if (error)
        goto fail_gunlock2;

    error = gfs2_rs_alloc(ip);
    if (error)
        goto fail_gunlock2;

    error = gfs2_acl_create(dip, inode);
    if (error)
        goto fail_gunlock2;

    error = gfs2_security_init(dip, ip, name);
    if (error)
        goto fail_gunlock2;

    error = link_dinode(dip, name, ip);
    if (error)
        goto fail_gunlock2;

    if (bh)
        brelse(bh);

    gfs2_trans_end(sdp);
    gfs2_inplace_release(dip);
    gfs2_quota_unlock(dip);
    mark_inode_dirty(inode);
    gfs2_glock_dq_uninit_m(2, ghs);
    d_instantiate(dentry, inode);
    return 0;

fail_gunlock2:
    gfs2_glock_dq_uninit(ghs + 1);
fail_gunlock:
    gfs2_glock_dq_uninit(ghs);
    if (inode && !IS_ERR(inode)) {
        set_bit(GIF_ALLOC_FAILED, &GFS2_I(inode)->i_flags);
        iput(inode);
    }
fail:
    gfs2_rs_delete(dip);
    if (bh)
        brelse(bh);
    return error;
}

static int gfs2_create(struct inode *dir, struct dentry *dentry,
               umode_t mode, bool excl)
{
    return gfs2_create_inode(dir, dentry, S_IFREG | mode, 0, NULL, 0, excl);
}

static struct dentry *gfs2_lookup(struct inode *dir, struct dentry *dentry,
                  unsigned int flags)
{
    struct inode *inode = gfs2_lookupi(dir, &dentry->d_name, 0);
    if (inode && !IS_ERR(inode)) {
        struct gfs2_glock *gl = GFS2_I(inode)->i_gl;
        struct gfs2_holder gh;
        int error;
        error = gfs2_glock_nq_init(gl, LM_ST_SHARED, LM_FLAG_ANY, &gh);
        if (error) {
            iput(inode);
            return ERR_PTR(error);
        }
        gfs2_glock_dq_uninit(&gh);
    }
    return d_splice_alias(inode, dentry);
}

static int gfs2_link(struct dentry *old_dentry, struct inode *dir,
             struct dentry *dentry)
{
    struct gfs2_inode *dip = GFS2_I(dir);
    struct gfs2_sbd *sdp = GFS2_SB(dir);
    struct inode *inode = old_dentry->d_inode;
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_holder ghs[2];
    struct buffer_head *dibh;
    int alloc_required;
    int error;

    if (S_ISDIR(inode->i_mode))
        return -EPERM;

    error = gfs2_rs_alloc(dip);
    if (error)
        return error;

    gfs2_holder_init(dip->i_gl, LM_ST_EXCLUSIVE, 0, ghs);
    gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + 1);

    error = gfs2_glock_nq(ghs); /* parent */
    if (error)
        goto out_parent;

    error = gfs2_glock_nq(ghs + 1); /* child */
    if (error)
        goto out_child;

    error = -ENOENT;
    if (inode->i_nlink == 0)
        goto out_gunlock;

    error = gfs2_permission(dir, MAY_WRITE | MAY_EXEC);
    if (error)
        goto out_gunlock;

    error = gfs2_dir_check(dir, &dentry->d_name, NULL);
    switch (error) {
    case -ENOENT:
        break;
    case 0:
        error = -EEXIST;
    default:
        goto out_gunlock;
    }

    error = -EINVAL;
    if (!dip->i_inode.i_nlink)
        goto out_gunlock;
    error = -EFBIG;
    if (dip->i_entries == (u32)-1)
        goto out_gunlock;
    error = -EPERM;
    if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
        goto out_gunlock;
    error = -EINVAL;
    if (!ip->i_inode.i_nlink)
        goto out_gunlock;
    error = -EMLINK;
    if (ip->i_inode.i_nlink == (u32)-1)
        goto out_gunlock;

    alloc_required = error = gfs2_diradd_alloc_required(dir, &dentry->d_name);
    if (error < 0)
        goto out_gunlock;
    error = 0;

    if (alloc_required) {
        error = gfs2_quota_lock_check(dip);
        if (error)
            goto out_gunlock;

        error = gfs2_inplace_reserve(dip, sdp->sd_max_dirres);
        if (error)
            goto out_gunlock_q;

        error = gfs2_trans_begin(sdp, sdp->sd_max_dirres +
                     gfs2_rg_blocks(dip, sdp->sd_max_dirres) +
                     2 * RES_DINODE + RES_STATFS +
                     RES_QUOTA, 0);
        if (error)
            goto out_ipres;
    } else {
        error = gfs2_trans_begin(sdp, 2 * RES_DINODE + RES_LEAF, 0);
        if (error)
            goto out_ipres;
    }

    error = gfs2_meta_inode_buffer(ip, &dibh);
    if (error)
        goto out_end_trans;

    error = gfs2_dir_add(dir, &dentry->d_name, ip);
    if (error)
        goto out_brelse;

    gfs2_trans_add_bh(ip->i_gl, dibh, 1);
    inc_nlink(&ip->i_inode);
    ip->i_inode.i_ctime = CURRENT_TIME;
    ihold(inode);
    d_instantiate(dentry, inode);
    mark_inode_dirty(inode);

out_brelse:
    brelse(dibh);
out_end_trans:
    gfs2_trans_end(sdp);
out_ipres:
    if (alloc_required)
        gfs2_inplace_release(dip);
out_gunlock_q:
    if (alloc_required)
        gfs2_quota_unlock(dip);
out_gunlock:
    gfs2_glock_dq(ghs + 1);
out_child:
    gfs2_glock_dq(ghs);
out_parent:
    gfs2_holder_uninit(ghs);
    gfs2_holder_uninit(ghs + 1);
    return error;
}

/*
 * gfs2_unlink_ok - check to see that a inode is still in a directory
 * @dip: the directory
 * @name: the name of the file
 * @ip: the inode
 *
 * Assumes that the lock on (at least) @dip is held.
 *
 * Returns: 0 if the parent/child relationship is correct, errno if it isn't
 */

static int gfs2_unlink_ok(struct gfs2_inode *dip, const struct qstr *name,
              const struct gfs2_inode *ip)
{
    int error;

    if (IS_IMMUTABLE(&ip->i_inode) || IS_APPEND(&ip->i_inode))
        return -EPERM;

    if ((dip->i_inode.i_mode & S_ISVTX) &&
        dip->i_inode.i_uid != current_fsuid() &&
        ip->i_inode.i_uid != current_fsuid() && !capable(CAP_FOWNER))
        return -EPERM;

    if (IS_APPEND(&dip->i_inode))
        return -EPERM;

    error = gfs2_permission(&dip->i_inode, MAY_WRITE | MAY_EXEC);
    if (error)
        return error;

    error = gfs2_dir_check(&dip->i_inode, name, ip);
    if (error)
        return error;

    return 0;
}

static int gfs2_unlink_inode(struct gfs2_inode *dip,
                 const struct dentry *dentry,
                 struct buffer_head *bh)
{
    struct inode *inode = dentry->d_inode;
    struct gfs2_inode *ip = GFS2_I(inode);
    int error;

    error = gfs2_dir_del(dip, dentry);
    if (error)
        return error;

    ip->i_entries = 0;
    inode->i_ctime = CURRENT_TIME;
    if (S_ISDIR(inode->i_mode))
        clear_nlink(inode);
    else
        drop_nlink(inode);
    mark_inode_dirty(inode);
    if (inode->i_nlink == 0)
        gfs2_unlink_di(inode);
    return 0;
}


static int gfs2_unlink(struct inode *dir, struct dentry *dentry)
{
    struct gfs2_inode *dip = GFS2_I(dir);
    struct gfs2_sbd *sdp = GFS2_SB(dir);
    struct inode *inode = dentry->d_inode;
    struct gfs2_inode *ip = GFS2_I(inode);
    struct buffer_head *bh;
    struct gfs2_holder ghs[3];
    struct gfs2_rgrpd *rgd;
    int error;

    error = gfs2_rindex_update(sdp);
    if (error)
        return error;

    error = -EROFS;

    gfs2_holder_init(dip->i_gl, LM_ST_EXCLUSIVE, 0, ghs);
    gfs2_holder_init(ip->i_gl,  LM_ST_EXCLUSIVE, 0, ghs + 1);

    rgd = gfs2_blk2rgrpd(sdp, ip->i_no_addr, 1);
    if (!rgd)
        goto out_inodes;

    gfs2_holder_init(rgd->rd_gl, LM_ST_EXCLUSIVE, 0, ghs + 2);


    error = gfs2_glock_nq(ghs); /* parent */
    if (error)
        goto out_parent;

    error = gfs2_glock_nq(ghs + 1); /* child */
    if (error)
        goto out_child;

    error = -ENOENT;
    if (inode->i_nlink == 0)
        goto out_rgrp;

    if (S_ISDIR(inode->i_mode)) {
        error = -ENOTEMPTY;
        if (ip->i_entries > 2 || inode->i_nlink > 2)
            goto out_rgrp;
    }

    error = gfs2_glock_nq(ghs + 2); /* rgrp */
    if (error)
        goto out_rgrp;

    error = gfs2_unlink_ok(dip, &dentry->d_name, ip);
    if (error)
        goto out_gunlock;

    error = gfs2_trans_begin(sdp, 2*RES_DINODE + 3*RES_LEAF + RES_RG_BIT, 0);
    if (error)
        goto out_gunlock;

    error = gfs2_meta_inode_buffer(ip, &bh);
    if (error)
        goto out_end_trans;

    error = gfs2_unlink_inode(dip, dentry, bh);
    brelse(bh);

out_end_trans:
    gfs2_trans_end(sdp);
out_gunlock:
    gfs2_glock_dq(ghs + 2);
out_rgrp:
    gfs2_glock_dq(ghs + 1);
out_child:
    gfs2_glock_dq(ghs);
out_parent:
    gfs2_holder_uninit(ghs + 2);
out_inodes:
    gfs2_holder_uninit(ghs + 1);
    gfs2_holder_uninit(ghs);
    return error;
}

static int gfs2_symlink(struct inode *dir, struct dentry *dentry,
            const char *symname)
{
    struct gfs2_sbd *sdp = GFS2_SB(dir);
    unsigned int size;

    size = strlen(symname);
    if (size > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode) - 1)
        return -ENAMETOOLONG;

    return gfs2_create_inode(dir, dentry, S_IFLNK | S_IRWXUGO, 0, symname, size, 0);
}

static int gfs2_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
    return gfs2_create_inode(dir, dentry, S_IFDIR | mode, 0, NULL, 0, 0);
}

static int gfs2_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
              dev_t dev)
{
    return gfs2_create_inode(dir, dentry, mode, dev, NULL, 0, 0);
}

/*
 * gfs2_ok_to_move - check if it's ok to move a directory to another directory
 * @this: move this
 * @to: to here
 *
 * Follow @to back to the root and make sure we don't encounter @this
 * Assumes we already hold the rename lock.
 *
 * Returns: errno
 */

static int gfs2_ok_to_move(struct gfs2_inode *this, struct gfs2_inode *to)
{
    struct inode *dir = &to->i_inode;
    struct super_block *sb = dir->i_sb;
    struct inode *tmp;
    int error = 0;

    igrab(dir);

    for (;;) {
        if (dir == &this->i_inode) {
            error = -EINVAL;
            break;
        }
        if (dir == sb->s_root->d_inode) {
            error = 0;
            break;
        }

        tmp = gfs2_lookupi(dir, &gfs2_qdotdot, 1);
        if (IS_ERR(tmp)) {
            error = PTR_ERR(tmp);
            break;
        }

        iput(dir);
        dir = tmp;
    }

    iput(dir);

    return error;
}

static int gfs2_rename(struct inode *odir, struct dentry *odentry,
               struct inode *ndir, struct dentry *ndentry)
{
    struct gfs2_inode *odip = GFS2_I(odir);
    struct gfs2_inode *ndip = GFS2_I(ndir);
    struct gfs2_inode *ip = GFS2_I(odentry->d_inode);
    struct gfs2_inode *nip = NULL;
    struct gfs2_sbd *sdp = GFS2_SB(odir);
    struct gfs2_holder ghs[5], r_gh = { .gh_gl = NULL, };
    struct gfs2_rgrpd *nrgd;
    unsigned int num_gh;
    int dir_rename = 0;
    int alloc_required = 0;
    unsigned int x;
    int error;

    if (ndentry->d_inode) {
        nip = GFS2_I(ndentry->d_inode);
        if (ip == nip)
            return 0;
    }

    error = gfs2_rindex_update(sdp);
    if (error)
        return error;

    error = gfs2_rs_alloc(ndip);
    if (error)
        return error;

    if (odip != ndip) {
        error = gfs2_glock_nq_init(sdp->sd_rename_gl, LM_ST_EXCLUSIVE,
                       0, &r_gh);
        if (error)
            goto out;

        if (S_ISDIR(ip->i_inode.i_mode)) {
            dir_rename = 1;
            /* don't move a dirctory into it's subdir */
            error = gfs2_ok_to_move(ip, ndip);
            if (error)
                goto out_gunlock_r;
        }
    }

    num_gh = 1;
    gfs2_holder_init(odip->i_gl, LM_ST_EXCLUSIVE, 0, ghs);
    if (odip != ndip) {
        gfs2_holder_init(ndip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh);
        num_gh++;
    }
    gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh);
    num_gh++;

    if (nip) {
        gfs2_holder_init(nip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh);
        num_gh++;
        /* grab the resource lock for unlink flag twiddling 
         * this is the case of the target file already existing
         * so we unlink before doing the rename
         */
        nrgd = gfs2_blk2rgrpd(sdp, nip->i_no_addr, 1);
        if (nrgd)
            gfs2_holder_init(nrgd->rd_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh++);
    }

    for (x = 0; x < num_gh; x++) {
        error = gfs2_glock_nq(ghs + x);
        if (error)
            goto out_gunlock;
    }

    error = -ENOENT;
    if (ip->i_inode.i_nlink == 0)
        goto out_gunlock;

    /* Check out the old directory */

    error = gfs2_unlink_ok(odip, &odentry->d_name, ip);
    if (error)
        goto out_gunlock;

    /* Check out the new directory */

    if (nip) {
        error = gfs2_unlink_ok(ndip, &ndentry->d_name, nip);
        if (error)
            goto out_gunlock;

        if (nip->i_inode.i_nlink == 0) {
            error = -EAGAIN;
            goto out_gunlock;
        }

        if (S_ISDIR(nip->i_inode.i_mode)) {
            if (nip->i_entries < 2) {
                gfs2_consist_inode(nip);
                error = -EIO;
                goto out_gunlock;
            }
            if (nip->i_entries > 2) {
                error = -ENOTEMPTY;
                goto out_gunlock;
            }
        }
    } else {
        error = gfs2_permission(ndir, MAY_WRITE | MAY_EXEC);
        if (error)
            goto out_gunlock;

        error = gfs2_dir_check(ndir, &ndentry->d_name, NULL);
        switch (error) {
        case -ENOENT:
            error = 0;
            break;
        case 0:
            error = -EEXIST;
        default:
            goto out_gunlock;
        };

        if (odip != ndip) {
            if (!ndip->i_inode.i_nlink) {
                error = -ENOENT;
                goto out_gunlock;
            }
            if (ndip->i_entries == (u32)-1) {
                error = -EFBIG;
                goto out_gunlock;
            }
            if (S_ISDIR(ip->i_inode.i_mode) &&
                ndip->i_inode.i_nlink == (u32)-1) {
                error = -EMLINK;
                goto out_gunlock;
            }
        }
    }

    /* Check out the dir to be renamed */

    if (dir_rename) {
        error = gfs2_permission(odentry->d_inode, MAY_WRITE);
        if (error)
            goto out_gunlock;
    }

    if (nip == NULL)
        alloc_required = gfs2_diradd_alloc_required(ndir, &ndentry->d_name);
    error = alloc_required;
    if (error < 0)
        goto out_gunlock;

    if (alloc_required) {
        error = gfs2_quota_lock_check(ndip);
        if (error)
            goto out_gunlock;

        error = gfs2_inplace_reserve(ndip, sdp->sd_max_dirres);
        if (error)
            goto out_gunlock_q;

        error = gfs2_trans_begin(sdp, sdp->sd_max_dirres +
                     gfs2_rg_blocks(ndip, sdp->sd_max_dirres) +
                     4 * RES_DINODE + 4 * RES_LEAF +
                     RES_STATFS + RES_QUOTA + 4, 0);
        if (error)
            goto out_ipreserv;
    } else {
        error = gfs2_trans_begin(sdp, 4 * RES_DINODE +
                     5 * RES_LEAF + 4, 0);
        if (error)
            goto out_gunlock;
    }

    /* Remove the target file, if it exists */

    if (nip) {
        struct buffer_head *bh;
        error = gfs2_meta_inode_buffer(nip, &bh);
        if (error)
            goto out_end_trans;
        error = gfs2_unlink_inode(ndip, ndentry, bh);
        brelse(bh);
    }

    if (dir_rename) {
        error = gfs2_dir_mvino(ip, &gfs2_qdotdot, ndip, DT_DIR);
        if (error)
            goto out_end_trans;
    } else {
        struct buffer_head *dibh;
        error = gfs2_meta_inode_buffer(ip, &dibh);
        if (error)
            goto out_end_trans;
        ip->i_inode.i_ctime = CURRENT_TIME;
        gfs2_trans_add_bh(ip->i_gl, dibh, 1);
        gfs2_dinode_out(ip, dibh->b_data);
        brelse(dibh);
    }

    error = gfs2_dir_del(odip, odentry);
    if (error)
        goto out_end_trans;

    error = gfs2_dir_add(ndir, &ndentry->d_name, ip);
    if (error)
        goto out_end_trans;

out_end_trans:
    gfs2_trans_end(sdp);
out_ipreserv:
    if (alloc_required)
        gfs2_inplace_release(ndip);
out_gunlock_q:
    if (alloc_required)
        gfs2_quota_unlock(ndip);
out_gunlock:
    while (x--) {
        gfs2_glock_dq(ghs + x);
        gfs2_holder_uninit(ghs + x);
    }
out_gunlock_r:
    if (r_gh.gh_gl)
        gfs2_glock_dq_uninit(&r_gh);
out:
    return error;
}

static void *gfs2_follow_link(struct dentry *dentry, struct nameidata *nd)
{
    struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
    struct gfs2_holder i_gh;
    struct buffer_head *dibh;
    unsigned int size;
    char *buf;
    int error;

    gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &i_gh);
    error = gfs2_glock_nq(&i_gh);
    if (error) {
        gfs2_holder_uninit(&i_gh);
        nd_set_link(nd, ERR_PTR(error));
        return NULL;
    }

    size = (unsigned int)i_size_read(&ip->i_inode);
    if (size == 0) {
        gfs2_consist_inode(ip);
        buf = ERR_PTR(-EIO);
        goto out;
    }

    error = gfs2_meta_inode_buffer(ip, &dibh);
    if (error) {
        buf = ERR_PTR(error);
        goto out;
    }

    buf = kzalloc(size + 1, GFP_NOFS);
    if (!buf)
        buf = ERR_PTR(-ENOMEM);
    else
        memcpy(buf, dibh->b_data + sizeof(struct gfs2_dinode), size);
    brelse(dibh);
out:
    gfs2_glock_dq_uninit(&i_gh);
    nd_set_link(nd, buf);
    return NULL;
}

static void gfs2_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
{
    char *s = nd_get_link(nd);
    if (!IS_ERR(s))
        kfree(s);
}

int gfs2_permission(struct inode *inode, int mask)
{
    struct gfs2_inode *ip;
    struct gfs2_holder i_gh;
    int error;
    int unlock = 0;


    ip = GFS2_I(inode);
    if (gfs2_glock_is_locked_by_me(ip->i_gl) == NULL) {
        if (mask & MAY_NOT_BLOCK)
            return -ECHILD;
        error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
        if (error)
            return error;
        unlock = 1;
    }

    if ((mask & MAY_WRITE) && IS_IMMUTABLE(inode))
        error = -EACCES;
    else
        error = generic_permission(inode, mask);
    if (unlock)
        gfs2_glock_dq_uninit(&i_gh);

    return error;
}

static int __gfs2_setattr_simple(struct inode *inode, struct iattr *attr)
{
    setattr_copy(inode, attr);
    mark_inode_dirty(inode);
    return 0;
}

int gfs2_setattr_simple(struct inode *inode, struct iattr *attr)
{
    int error;

    if (current->journal_info)
        return __gfs2_setattr_simple(inode, attr);

    error = gfs2_trans_begin(GFS2_SB(inode), RES_DINODE, 0);
    if (error)
        return error;

    error = __gfs2_setattr_simple(inode, attr);
    gfs2_trans_end(GFS2_SB(inode));
    return error;
}

static int setattr_chown(struct inode *inode, struct iattr *attr)
{
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_sbd *sdp = GFS2_SB(inode);
    u32 ouid, ogid, nuid, ngid;
    int error;

    ouid = inode->i_uid;
    ogid = inode->i_gid;
    nuid = attr->ia_uid;
    ngid = attr->ia_gid;

    if (!(attr->ia_valid & ATTR_UID) || ouid == nuid)
        ouid = nuid = NO_QUOTA_CHANGE;
    if (!(attr->ia_valid & ATTR_GID) || ogid == ngid)
        ogid = ngid = NO_QUOTA_CHANGE;

    error = gfs2_quota_lock(ip, nuid, ngid);
    if (error)
        return error;

    if (ouid != NO_QUOTA_CHANGE || ogid != NO_QUOTA_CHANGE) {
        error = gfs2_quota_check(ip, nuid, ngid);
        if (error)
            goto out_gunlock_q;
    }

    error = gfs2_trans_begin(sdp, RES_DINODE + 2 * RES_QUOTA, 0);
    if (error)
        goto out_gunlock_q;

    error = gfs2_setattr_simple(inode, attr);
    if (error)
        goto out_end_trans;

    if (ouid != NO_QUOTA_CHANGE || ogid != NO_QUOTA_CHANGE) {
        u64 blocks = gfs2_get_inode_blocks(&ip->i_inode);
        gfs2_quota_change(ip, -blocks, ouid, ogid);
        gfs2_quota_change(ip, blocks, nuid, ngid);
    }

out_end_trans:
    gfs2_trans_end(sdp);
out_gunlock_q:
    gfs2_quota_unlock(ip);
    return error;
}

static int gfs2_setattr(struct dentry *dentry, struct iattr *attr)
{
    struct inode *inode = dentry->d_inode;
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_holder i_gh;
    int error;

    error = gfs2_rs_alloc(ip);
    if (error)
        return error;

    error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh);
    if (error)
        return error;

    error = -EPERM;
    if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
        goto out;

    error = inode_change_ok(inode, attr);
    if (error)
        goto out;

    if (attr->ia_valid & ATTR_SIZE)
        error = gfs2_setattr_size(inode, attr->ia_size);
    else if (attr->ia_valid & (ATTR_UID | ATTR_GID))
        error = setattr_chown(inode, attr);
    else if ((attr->ia_valid & ATTR_MODE) && IS_POSIXACL(inode))
        error = gfs2_acl_chmod(ip, attr);
    else
        error = gfs2_setattr_simple(inode, attr);

out:
    if (!error)
        mark_inode_dirty(inode);
    gfs2_glock_dq_uninit(&i_gh);
    return error;
}

static int gfs2_getattr(struct vfsmount *mnt, struct dentry *dentry,
            struct kstat *stat)
{
    struct inode *inode = dentry->d_inode;
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_holder gh;
    int error;
    int unlock = 0;

    if (gfs2_glock_is_locked_by_me(ip->i_gl) == NULL) {
        error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &gh);
        if (error)
            return error;
        unlock = 1;
    }

    generic_fillattr(inode, stat);
    if (unlock)
        gfs2_glock_dq_uninit(&gh);

    return 0;
}

static int gfs2_setxattr(struct dentry *dentry, const char *name,
             const void *data, size_t size, int flags)
{
    struct inode *inode = dentry->d_inode;
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_holder gh;
    int ret;

    gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
    ret = gfs2_glock_nq(&gh);
    if (ret == 0) {
        ret = gfs2_rs_alloc(ip);
        if (ret == 0)
            ret = generic_setxattr(dentry, name, data, size, flags);
        gfs2_glock_dq(&gh);
    }
    gfs2_holder_uninit(&gh);
    return ret;
}

static ssize_t gfs2_getxattr(struct dentry *dentry, const char *name,
                 void *data, size_t size)
{
    struct inode *inode = dentry->d_inode;
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_holder gh;
    int ret;

    gfs2_holder_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &gh);
    ret = gfs2_glock_nq(&gh);
    if (ret == 0) {
        ret = generic_getxattr(dentry, name, data, size);
        gfs2_glock_dq(&gh);
    }
    gfs2_holder_uninit(&gh);
    return ret;
}

static int gfs2_removexattr(struct dentry *dentry, const char *name)
{
    struct inode *inode = dentry->d_inode;
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_holder gh;
    int ret;

    gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
    ret = gfs2_glock_nq(&gh);
    if (ret == 0) {
        ret = gfs2_rs_alloc(ip);
        if (ret == 0)
            ret = generic_removexattr(dentry, name);
        gfs2_glock_dq(&gh);
    }
    gfs2_holder_uninit(&gh);
    return ret;
}

static int gfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
               u64 start, u64 len)
{
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_holder gh;
    int ret;

    ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
    if (ret)
        return ret;

    mutex_lock(&inode->i_mutex);

    ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
    if (ret)
        goto out;

    if (gfs2_is_stuffed(ip)) {
        u64 phys = ip->i_no_addr << inode->i_blkbits;
        u64 size = i_size_read(inode);
        u32 flags = FIEMAP_EXTENT_LAST|FIEMAP_EXTENT_NOT_ALIGNED|
                FIEMAP_EXTENT_DATA_INLINE;
        phys += sizeof(struct gfs2_dinode);
        phys += start;
        if (start + len > size)
            len = size - start;
        if (start < size)
            ret = fiemap_fill_next_extent(fieinfo, start, phys,
                              len, flags);
        if (ret == 1)
            ret = 0;
    } else {
        ret = __generic_block_fiemap(inode, fieinfo, start, len,
                         gfs2_block_map);
    }

    gfs2_glock_dq_uninit(&gh);
out:
    mutex_unlock(&inode->i_mutex);
    return ret;
}

const struct inode_operations gfs2_file_iops = {
    .permission = gfs2_permission,
    .setattr = gfs2_setattr,
    .getattr = gfs2_getattr,
    .setxattr = gfs2_setxattr,
    .getxattr = gfs2_getxattr,
    .listxattr = gfs2_listxattr,
    .removexattr = gfs2_removexattr,
    .fiemap = gfs2_fiemap,
    .get_acl = gfs2_get_acl,
};

const struct inode_operations gfs2_dir_iops = {
    .create = gfs2_create,
    .lookup = gfs2_lookup,
    .link = gfs2_link,
    .unlink = gfs2_unlink,
    .symlink = gfs2_symlink,
    .mkdir = gfs2_mkdir,
    .rmdir = gfs2_unlink,
    .mknod = gfs2_mknod,
    .rename = gfs2_rename,
    .permission = gfs2_permission,
    .setattr = gfs2_setattr,
    .getattr = gfs2_getattr,
    .setxattr = gfs2_setxattr,
    .getxattr = gfs2_getxattr,
    .listxattr = gfs2_listxattr,
    .removexattr = gfs2_removexattr,
    .fiemap = gfs2_fiemap,
    .get_acl = gfs2_get_acl,
};

const struct inode_operations gfs2_symlink_iops = {
    .readlink = generic_readlink,
    .follow_link = gfs2_follow_link,
    .put_link = gfs2_put_link,
    .permission = gfs2_permission,
    .setattr = gfs2_setattr,
    .getattr = gfs2_getattr,
    .setxattr = gfs2_setxattr,
    .getxattr = gfs2_getxattr,
    .listxattr = gfs2_listxattr,
    .removexattr = gfs2_removexattr,
    .fiemap = gfs2_fiemap,
    .get_acl = gfs2_get_acl,
};