/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 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 <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"

/**
 * gfs2_create - Create a file
 * @dir: The directory in which to create the file
 * @dentry: The dentry of the new file
 * @mode: The mode of the new file
 *
 * Returns: errno
 */

static int gfs2_create(struct inode *dir, struct dentry *dentry,
                       int mode, struct nameidata *nd)
{
        struct gfs2_inode *dip = GFS2_I(dir);
        struct gfs2_sbd *sdp = GFS2_SB(dir);
        struct gfs2_holder ghs[2];
        struct inode *inode;

        gfs2_holder_init(dip->i_gl, 0, 0, ghs);

        for (;;) {
                inode = gfs2_createi(ghs, &dentry->d_name, S_IFREG | mode, 0);
                if (!IS_ERR(inode)) {
                        gfs2_trans_end(sdp);
                        if (dip->i_alloc->al_rgd)
                                gfs2_inplace_release(dip);
                        gfs2_quota_unlock(dip);
                        gfs2_alloc_put(dip);
                        gfs2_glock_dq_uninit_m(2, ghs);
                        mark_inode_dirty(inode);
                        break;
                } else if (PTR_ERR(inode) != -EEXIST ||
                           (nd && nd->flags & LOOKUP_EXCL)) {
                        gfs2_holder_uninit(ghs);
                        return PTR_ERR(inode);
                }

                inode = gfs2_lookupi(dir, &dentry->d_name, 0);
                if (inode) {
                        if (!IS_ERR(inode)) {
                                gfs2_holder_uninit(ghs);
                                break;
                        } else {
                                gfs2_holder_uninit(ghs);
                                return PTR_ERR(inode);
                        }
                }
        }

        d_instantiate(dentry, inode);

        return 0;
}

/**
 * gfs2_lookup - Look up a filename in a directory and return its inode
 * @dir: The directory inode
 * @dentry: The dentry of the new inode
 * @nd: passed from Linux VFS, ignored by us
 *
 * Called by the VFS layer. Lock dir and call gfs2_lookupi()
 *
 * Returns: errno
 */

static struct dentry *gfs2_lookup(struct inode *dir, struct dentry *dentry,
                                  struct nameidata *nd)
{
        struct inode *inode = NULL;

        inode = gfs2_lookupi(dir, &dentry->d_name, 0);
        if (inode && IS_ERR(inode))
                return ERR_CAST(inode);

        if (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);
        }
        d_add(dentry, inode);

        return NULL;
}

/**
 * gfs2_link - Link to a file
 * @old_dentry: The inode to link
 * @dir: Add link to this directory
 * @dentry: The name of the link
 *
 * Link the inode in "old_dentry" into the directory "dir" with the
 * name in "dentry".
 *
 * Returns: errno
 */

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];
        int alloc_required;
        int error;

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

        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 = gfs2_permission(dir, MAY_WRITE | MAY_EXEC, 0);
        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) {
                struct gfs2_alloc *al = gfs2_alloc_get(dip);
                if (!al) {
                        error = -ENOMEM;
                        goto out_gunlock;
                }

                error = gfs2_quota_lock_check(dip);
                if (error)
                        goto out_alloc;

                al->al_requested = sdp->sd_max_dirres;

                error = gfs2_inplace_reserve(dip);
                if (error)
                        goto out_gunlock_q;

                error = gfs2_trans_begin(sdp, sdp->sd_max_dirres +
                                         gfs2_rg_blocks(al) +
                                         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_dir_add(dir, &dentry->d_name, ip, IF2DT(inode->i_mode));
        if (error)
                goto out_end_trans;

        error = gfs2_change_nlink(ip, +1);

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_alloc:
        if (alloc_required)
                gfs2_alloc_put(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);
        if (!error) {
                ihold(inode);
                d_instantiate(dentry, inode);
                mark_inode_dirty(inode);
        }
        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, 0);
        if (error)
                return error;

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

        return 0;
}

/**
 * gfs2_unlink - Unlink a file
 * @dir: The inode of the directory containing the file to unlink
 * @dentry: The file itself
 *
 * Unlink a file.  Call gfs2_unlinki()
 *
 * Returns: errno
 */

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 gfs2_inode *ip = GFS2_I(dentry->d_inode);
        struct gfs2_holder ghs[3];
        struct gfs2_rgrpd *rgd;
        struct gfs2_holder ri_gh;
        int error;

        error = gfs2_rindex_hold(sdp, &ri_gh);
        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);

        rgd = gfs2_blk2rgrpd(sdp, ip->i_no_addr);
        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 = 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 + RES_LEAF + RES_RG_BIT, 0);
        if (error)
                goto out_gunlock;

        error = gfs2_dir_del(dip, &dentry->d_name);
        if (error)
                goto out_end_trans;

        error = gfs2_change_nlink(ip, -1);

out_end_trans:
        gfs2_trans_end(sdp);
out_gunlock:
        gfs2_glock_dq(ghs + 2);
out_rgrp:
        gfs2_holder_uninit(ghs + 2);
        gfs2_glock_dq(ghs + 1);
out_child:
        gfs2_holder_uninit(ghs + 1);
        gfs2_glock_dq(ghs);
out_parent:
        gfs2_holder_uninit(ghs);
        gfs2_glock_dq_uninit(&ri_gh);
        return error;
}

/**
 * gfs2_symlink - Create a symlink
 * @dir: The directory to create the symlink in
 * @dentry: The dentry to put the symlink in
 * @symname: The thing which the link points to
 *
 * Returns: errno
 */

static int gfs2_symlink(struct inode *dir, struct dentry *dentry,
                        const char *symname)
{
        struct gfs2_inode *dip = GFS2_I(dir), *ip;
        struct gfs2_sbd *sdp = GFS2_SB(dir);
        struct gfs2_holder ghs[2];
        struct inode *inode;
        struct buffer_head *dibh;
        int size;
        int error;

        /* Must be stuffed with a null terminator for gfs2_follow_link() */
        size = strlen(symname);
        if (size > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode) - 1)
                return -ENAMETOOLONG;

        gfs2_holder_init(dip->i_gl, 0, 0, ghs);

        inode = gfs2_createi(ghs, &dentry->d_name, S_IFLNK | S_IRWXUGO, 0);
        if (IS_ERR(inode)) {
                gfs2_holder_uninit(ghs);
                return PTR_ERR(inode);
        }

        ip = ghs[1].gh_gl->gl_object;

        i_size_write(inode, size);

        error = gfs2_meta_inode_buffer(ip, &dibh);

        if (!gfs2_assert_withdraw(sdp, !error)) {
                gfs2_dinode_out(ip, dibh->b_data);
                memcpy(dibh->b_data + sizeof(struct gfs2_dinode), symname,
                       size);
                brelse(dibh);
        }

        gfs2_trans_end(sdp);
        if (dip->i_alloc->al_rgd)
                gfs2_inplace_release(dip);
        gfs2_quota_unlock(dip);
        gfs2_alloc_put(dip);

        gfs2_glock_dq_uninit_m(2, ghs);

        d_instantiate(dentry, inode);
        mark_inode_dirty(inode);

        return 0;
}

/**
 * gfs2_mkdir - Make a directory
 * @dir: The parent directory of the new one
 * @dentry: The dentry of the new directory
 * @mode: The mode of the new directory
 *
 * Returns: errno
 */

static int gfs2_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
        struct gfs2_inode *dip = GFS2_I(dir), *ip;
        struct gfs2_sbd *sdp = GFS2_SB(dir);
        struct gfs2_holder ghs[2];
        struct inode *inode;
        struct buffer_head *dibh;
        int error;

        gfs2_holder_init(dip->i_gl, 0, 0, ghs);

        inode = gfs2_createi(ghs, &dentry->d_name, S_IFDIR | mode, 0);
        if (IS_ERR(inode)) {
                gfs2_holder_uninit(ghs);
                return PTR_ERR(inode);
        }

        ip = ghs[1].gh_gl->gl_object;

        ip->i_inode.i_nlink = 2;
        i_size_write(inode, sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode));
        ip->i_diskflags |= GFS2_DIF_JDATA;
        ip->i_entries = 2;

        error = gfs2_meta_inode_buffer(ip, &dibh);

        if (!gfs2_assert_withdraw(sdp, !error)) {
                struct gfs2_dinode *di = (struct gfs2_dinode *)dibh->b_data;
                struct gfs2_dirent *dent = (struct gfs2_dirent *)(di+1);

                gfs2_trans_add_bh(ip->i_gl, dibh, 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);
                di->di_entries = cpu_to_be32(1);

                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(dip, dent);
                dent->de_type = cpu_to_be16(DT_DIR);

                gfs2_dinode_out(ip, di);

                brelse(dibh);
        }

        error = gfs2_change_nlink(dip, +1);
        gfs2_assert_withdraw(sdp, !error); /* dip already pinned */

        gfs2_trans_end(sdp);
        if (dip->i_alloc->al_rgd)
                gfs2_inplace_release(dip);
        gfs2_quota_unlock(dip);
        gfs2_alloc_put(dip);

        gfs2_glock_dq_uninit_m(2, ghs);

        d_instantiate(dentry, inode);
        mark_inode_dirty(inode);

        return 0;
}

/**
 * gfs2_rmdiri - Remove a directory
 * @dip: The parent directory of the directory to be removed
 * @name: The name of the directory to be removed
 * @ip: The GFS2 inode of the directory to be removed
 *
 * Assumes Glocks on dip and ip are held
 *
 * Returns: errno
 */

static int gfs2_rmdiri(struct gfs2_inode *dip, const struct qstr *name,
                       struct gfs2_inode *ip)
{
        int error;

        if (ip->i_entries != 2) {
                if (gfs2_consist_inode(ip))
                        gfs2_dinode_print(ip);
                return -EIO;
        }

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

        error = gfs2_change_nlink(dip, -1);
        if (error)
                return error;

        error = gfs2_dir_del(ip, &gfs2_qdot);
        if (error)
                return error;

        error = gfs2_dir_del(ip, &gfs2_qdotdot);
        if (error)
                return error;

        /* It looks odd, but it really should be done twice */
        error = gfs2_change_nlink(ip, -1);
        if (error)
                return error;

        error = gfs2_change_nlink(ip, -1);
        if (error)
                return error;

        return error;
}

/**
 * gfs2_rmdir - Remove a directory
 * @dir: The parent directory of the directory to be removed
 * @dentry: The dentry of the directory to remove
 *
 * Remove a directory. Call gfs2_rmdiri()
 *
 * Returns: errno
 */

static int gfs2_rmdir(struct inode *dir, struct dentry *dentry)
{
        struct gfs2_inode *dip = GFS2_I(dir);
        struct gfs2_sbd *sdp = GFS2_SB(dir);
        struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
        struct gfs2_holder ghs[3];
        struct gfs2_rgrpd *rgd;
        struct gfs2_holder ri_gh;
        int error;

        error = gfs2_rindex_hold(sdp, &ri_gh);
        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);

        rgd = gfs2_blk2rgrpd(sdp, ip->i_no_addr);
        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 = 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;

        if (ip->i_entries < 2) {
                if (gfs2_consist_inode(ip))
                        gfs2_dinode_print(ip);
                error = -EIO;
                goto out_gunlock;
        }
        if (ip->i_entries > 2) {
                error = -ENOTEMPTY;
                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_rmdiri(dip, &dentry->d_name, ip);

        gfs2_trans_end(sdp);

out_gunlock:
        gfs2_glock_dq(ghs + 2);
out_rgrp:
        gfs2_holder_uninit(ghs + 2);
        gfs2_glock_dq(ghs + 1);
out_child:
        gfs2_holder_uninit(ghs + 1);
        gfs2_glock_dq(ghs);
out_parent:
        gfs2_holder_uninit(ghs);
        gfs2_glock_dq_uninit(&ri_gh);
        return error;
}

/**
 * gfs2_mknod - Make a special file
 * @dir: The directory in which the special file will reside
 * @dentry: The dentry of the special file
 * @mode: The mode of the special file
 * @rdev: The device specification of the special file
 *
 */

static int gfs2_mknod(struct inode *dir, struct dentry *dentry, int mode,
                      dev_t dev)
{
        struct gfs2_inode *dip = GFS2_I(dir);
        struct gfs2_sbd *sdp = GFS2_SB(dir);
        struct gfs2_holder ghs[2];
        struct inode *inode;

        gfs2_holder_init(dip->i_gl, 0, 0, ghs);

        inode = gfs2_createi(ghs, &dentry->d_name, mode, dev);
        if (IS_ERR(inode)) {
                gfs2_holder_uninit(ghs);
                return PTR_ERR(inode);
        }

        gfs2_trans_end(sdp);
        if (dip->i_alloc->al_rgd)
                gfs2_inplace_release(dip);
        gfs2_quota_unlock(dip);
        gfs2_alloc_put(dip);

        gfs2_glock_dq_uninit_m(2, ghs);

        d_instantiate(dentry, inode);
        mark_inode_dirty(inode);

        return 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;
}

/**
 * gfs2_rename - Rename a file
 * @odir: Parent directory of old file name
 * @odentry: The old dentry of the file
 * @ndir: Parent directory of new file name
 * @ndentry: The new dentry of the file
 *
 * Returns: errno
 */

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, }, ri_gh;
        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_hold(sdp, &ri_gh);
        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);
                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;
        }

        /* 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 (S_ISDIR(nip->i_inode.i_mode)) {
                        if (nip->i_entries < 2) {
                                if (gfs2_consist_inode(nip))
                                        gfs2_dinode_print(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, 0);
                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 = -EINVAL;
                                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, 0);
                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;
        error = 0;

        if (alloc_required) {
                struct gfs2_alloc *al = gfs2_alloc_get(ndip);
                if (!al) {
                        error = -ENOMEM;
                        goto out_gunlock;
                }

                error = gfs2_quota_lock_check(ndip);
                if (error)
                        goto out_alloc;

                al->al_requested = sdp->sd_max_dirres;

                error = gfs2_inplace_reserve_ri(ndip);
                if (error)
                        goto out_gunlock_q;

                error = gfs2_trans_begin(sdp, sdp->sd_max_dirres +
                                         gfs2_rg_blocks(al) +
                                         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) {
                if (S_ISDIR(nip->i_inode.i_mode))
                        error = gfs2_rmdiri(ndip, &ndentry->d_name, nip);
                else {
                        error = gfs2_dir_del(ndip, &ndentry->d_name);
                        if (error)
                                goto out_end_trans;
                        error = gfs2_change_nlink(nip, -1);
                }
                if (error)
                        goto out_end_trans;
        }

        if (dir_rename) {
                error = gfs2_change_nlink(ndip, +1);
                if (error)
                        goto out_end_trans;
                error = gfs2_change_nlink(odip, -1);
                if (error)
                        goto out_end_trans;

                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->d_name);
        if (error)
                goto out_end_trans;

        error = gfs2_dir_add(ndir, &ndentry->d_name, ip, IF2DT(ip->i_inode.i_mode));
        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_alloc:
        if (alloc_required)
                gfs2_alloc_put(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:
        gfs2_glock_dq_uninit(&ri_gh);
        return error;
}

/**
 * gfs2_follow_link - Follow a symbolic link
 * @dentry: The dentry of the link
 * @nd: Data that we pass to vfs_follow_link()
 *
 * This can handle symlinks of any size.
 *
 * Returns: 0 on success or error code
 */

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 x, 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;
        }

        x = size + 1;
        buf = kmalloc(x, GFP_NOFS);
        if (!buf)
                buf = ERR_PTR(-ENOMEM);
        else
                memcpy(buf, dibh->b_data + sizeof(struct gfs2_dinode), x);
        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);
}

/**
 * gfs2_permission -
 * @inode: The inode
 * @mask: The mask to be tested
 * @flags: Indicates whether this is an RCU path walk or not
 *
 * This may be called from the VFS directly, or from within GFS2 with the
 * inode locked, so we look to see if the glock is already locked and only
 * lock the glock if its not already been done.
 *
 * Returns: errno
 */

int gfs2_permission(struct inode *inode, int mask, unsigned int flags)
{
        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 (flags & IPERM_FLAG_RCU)
                        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, flags, gfs2_check_acl);
        if (unlock)
                gfs2_glock_dq_uninit(&i_gh);

        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;

        if (!gfs2_alloc_get(ip))
                return -ENOMEM;

        error = gfs2_quota_lock(ip, nuid, ngid);
        if (error)
                goto out_alloc;

        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(ip, 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);
out_alloc:
        gfs2_alloc_put(ip);
        return error;
}

/**
 * gfs2_setattr - Change attributes on an inode
 * @dentry: The dentry which is changing
 * @attr: The structure describing the change
 *
 * The VFS layer wants to change one or more of an inodes attributes.  Write
 * that change out to disk.
 *
 * Returns: errno
 */

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_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(ip, attr);

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

/**
 * gfs2_getattr - Read out an inode's attributes
 * @mnt: The vfsmount the inode is being accessed from
 * @dentry: The dentry to stat
 * @stat: The inode's stats
 *
 * This may be called from the VFS directly, or from within GFS2 with the
 * inode locked, so we look to see if the glock is already locked and only
 * lock the glock if its not already been done. Note that its the NFS
 * readdirplus operation which causes this to be called (from filldir)
 * with the glock already held.
 *
 * Returns: errno
 */

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 = 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 = 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,
};

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_rmdir,
        .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,
};

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,
};