file.c

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/*
 * 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/pagemap.h>
#include <linux/uio.h>
#include <linux/blkdev.h>
#include <linux/mm.h>
#include <linux/mount.h>
#include <linux/fs.h>
#include <linux/gfs2_ondisk.h>
#include <linux/falloc.h>
#include <linux/swap.h>
#include <linux/crc32.h>
#include <linux/writeback.h>
#include <asm/uaccess.h>
#include <linux/dlm.h>
#include <linux/dlm_plock.h>

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

static loff_t gfs2_llseek(struct file *file, loff_t offset, int origin)
{
    struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
    struct gfs2_holder i_gh;
    loff_t error;

    switch (origin) {
    case SEEK_END: /* These reference inode->i_size */
    case SEEK_DATA:
    case SEEK_HOLE:
        error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY,
                       &i_gh);
        if (!error) {
            error = generic_file_llseek(file, offset, origin);
            gfs2_glock_dq_uninit(&i_gh);
        }
        break;
    case SEEK_CUR:
    case SEEK_SET:
        error = generic_file_llseek(file, offset, origin);
        break;
    default:
        error = -EINVAL;
    }

    return error;
}

static int gfs2_readdir(struct file *file, void *dirent, filldir_t filldir)
{
    struct inode *dir = file->f_mapping->host;
    struct gfs2_inode *dip = GFS2_I(dir);
    struct gfs2_holder d_gh;
    u64 offset = file->f_pos;
    int error;

    gfs2_holder_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
    error = gfs2_glock_nq(&d_gh);
    if (error) {
        gfs2_holder_uninit(&d_gh);
        return error;
    }

    error = gfs2_dir_read(dir, &offset, dirent, filldir, &file->f_ra);

    gfs2_glock_dq_uninit(&d_gh);

    file->f_pos = offset;

    return error;
}

static u32 fsflags_cvt(const u32 *table, u32 val)
{
    u32 res = 0;
    while(val) {
        if (val & 1)
            res |= *table;
        table++;
        val >>= 1;
    }
    return res;
}

static const u32 fsflags_to_gfs2[32] = {
    [3] = GFS2_DIF_SYNC,
    [4] = GFS2_DIF_IMMUTABLE,
    [5] = GFS2_DIF_APPENDONLY,
    [7] = GFS2_DIF_NOATIME,
    [12] = GFS2_DIF_EXHASH,
    [14] = GFS2_DIF_INHERIT_JDATA,
    [17] = GFS2_DIF_TOPDIR,
};

static const u32 gfs2_to_fsflags[32] = {
    [gfs2fl_Sync] = FS_SYNC_FL,
    [gfs2fl_Immutable] = FS_IMMUTABLE_FL,
    [gfs2fl_AppendOnly] = FS_APPEND_FL,
    [gfs2fl_NoAtime] = FS_NOATIME_FL,
    [gfs2fl_ExHash] = FS_INDEX_FL,
    [gfs2fl_TopLevel] = FS_TOPDIR_FL,
    [gfs2fl_InheritJdata] = FS_JOURNAL_DATA_FL,
};

static int gfs2_get_flags(struct file *filp, u32 __user *ptr)
{
    struct inode *inode = filp->f_path.dentry->d_inode;
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_holder gh;
    int error;
    u32 fsflags;

    gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
    error = gfs2_glock_nq(&gh);
    if (error)
        return error;

    fsflags = fsflags_cvt(gfs2_to_fsflags, ip->i_diskflags);
    if (!S_ISDIR(inode->i_mode) && ip->i_diskflags & GFS2_DIF_JDATA)
        fsflags |= FS_JOURNAL_DATA_FL;
    if (put_user(fsflags, ptr))
        error = -EFAULT;

    gfs2_glock_dq(&gh);
    gfs2_holder_uninit(&gh);
    return error;
}

void gfs2_set_inode_flags(struct inode *inode)
{
    struct gfs2_inode *ip = GFS2_I(inode);
    unsigned int flags = inode->i_flags;

    flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_NOSEC);
    if ((ip->i_eattr == 0) && !is_sxid(inode->i_mode))
        inode->i_flags |= S_NOSEC;
    if (ip->i_diskflags & GFS2_DIF_IMMUTABLE)
        flags |= S_IMMUTABLE;
    if (ip->i_diskflags & GFS2_DIF_APPENDONLY)
        flags |= S_APPEND;
    if (ip->i_diskflags & GFS2_DIF_NOATIME)
        flags |= S_NOATIME;
    if (ip->i_diskflags & GFS2_DIF_SYNC)
        flags |= S_SYNC;
    inode->i_flags = flags;
}

/* Flags that can be set by user space */
#define GFS2_FLAGS_USER_SET (GFS2_DIF_JDATA|            \
                 GFS2_DIF_IMMUTABLE|        \
                 GFS2_DIF_APPENDONLY|       \
                 GFS2_DIF_NOATIME|          \
                 GFS2_DIF_SYNC|         \
                 GFS2_DIF_SYSTEM|           \
                 GFS2_DIF_TOPDIR|           \
                 GFS2_DIF_INHERIT_JDATA)

static int do_gfs2_set_flags(struct file *filp, u32 reqflags, u32 mask)
{
    struct inode *inode = filp->f_path.dentry->d_inode;
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_sbd *sdp = GFS2_SB(inode);
    struct buffer_head *bh;
    struct gfs2_holder gh;
    int error;
    u32 new_flags, flags;

    error = mnt_want_write_file(filp);
    if (error)
        return error;

    error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
    if (error)
        goto out_drop_write;

    error = -EACCES;
    if (!inode_owner_or_capable(inode))
        goto out;

    error = 0;
    flags = ip->i_diskflags;
    new_flags = (flags & ~mask) | (reqflags & mask);
    if ((new_flags ^ flags) == 0)
        goto out;

    error = -EINVAL;
    if ((new_flags ^ flags) & ~GFS2_FLAGS_USER_SET)
        goto out;

    error = -EPERM;
    if (IS_IMMUTABLE(inode) && (new_flags & GFS2_DIF_IMMUTABLE))
        goto out;
    if (IS_APPEND(inode) && (new_flags & GFS2_DIF_APPENDONLY))
        goto out;
    if (((new_flags ^ flags) & GFS2_DIF_IMMUTABLE) &&
        !capable(CAP_LINUX_IMMUTABLE))
        goto out;
    if (!IS_IMMUTABLE(inode)) {
        error = gfs2_permission(inode, MAY_WRITE);
        if (error)
            goto out;
    }
    if ((flags ^ new_flags) & GFS2_DIF_JDATA) {
        if (flags & GFS2_DIF_JDATA)
            gfs2_log_flush(sdp, ip->i_gl);
        error = filemap_fdatawrite(inode->i_mapping);
        if (error)
            goto out;
        error = filemap_fdatawait(inode->i_mapping);
        if (error)
            goto out;
    }
    error = gfs2_trans_begin(sdp, RES_DINODE, 0);
    if (error)
        goto out;
    error = gfs2_meta_inode_buffer(ip, &bh);
    if (error)
        goto out_trans_end;
    gfs2_trans_add_bh(ip->i_gl, bh, 1);
    ip->i_diskflags = new_flags;
    gfs2_dinode_out(ip, bh->b_data);
    brelse(bh);
    gfs2_set_inode_flags(inode);
    gfs2_set_aops(inode);
out_trans_end:
    gfs2_trans_end(sdp);
out:
    gfs2_glock_dq_uninit(&gh);
out_drop_write:
    mnt_drop_write_file(filp);
    return error;
}

static int gfs2_set_flags(struct file *filp, u32 __user *ptr)
{
    struct inode *inode = filp->f_path.dentry->d_inode;
    u32 fsflags, gfsflags;

    if (get_user(fsflags, ptr))
        return -EFAULT;

    gfsflags = fsflags_cvt(fsflags_to_gfs2, fsflags);
    if (!S_ISDIR(inode->i_mode)) {
        gfsflags &= ~GFS2_DIF_TOPDIR;
        if (gfsflags & GFS2_DIF_INHERIT_JDATA)
            gfsflags ^= (GFS2_DIF_JDATA | GFS2_DIF_INHERIT_JDATA);
        return do_gfs2_set_flags(filp, gfsflags, ~0);
    }
    return do_gfs2_set_flags(filp, gfsflags, ~GFS2_DIF_JDATA);
}

static long gfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
    switch(cmd) {
    case FS_IOC_GETFLAGS:
        return gfs2_get_flags(filp, (u32 __user *)arg);
    case FS_IOC_SETFLAGS:
        return gfs2_set_flags(filp, (u32 __user *)arg);
    case FITRIM:
        return gfs2_fitrim(filp, (void __user *)arg);
    }
    return -ENOTTY;
}

static void gfs2_size_hint(struct file *filep, loff_t offset, size_t size)
{
    struct inode *inode = filep->f_dentry->d_inode;
    struct gfs2_sbd *sdp = GFS2_SB(inode);
    struct gfs2_inode *ip = GFS2_I(inode);
    size_t blks = (size + sdp->sd_sb.sb_bsize - 1) >> sdp->sd_sb.sb_bsize_shift;
    int hint = min_t(size_t, INT_MAX, blks);

    atomic_set(&ip->i_res->rs_sizehint, hint);
}

static int gfs2_allocate_page_backing(struct page *page)
{
    struct inode *inode = page->mapping->host;
    struct buffer_head bh;
    unsigned long size = PAGE_CACHE_SIZE;
    u64 lblock = page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);

    do {
        bh.b_state = 0;
        bh.b_size = size;
        gfs2_block_map(inode, lblock, &bh, 1);
        if (!buffer_mapped(&bh))
            return -EIO;
        size -= bh.b_size;
        lblock += (bh.b_size >> inode->i_blkbits);
    } while(size > 0);
    return 0;
}

static int gfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
    struct page *page = vmf->page;
    struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_sbd *sdp = GFS2_SB(inode);
    unsigned long last_index;
    u64 pos = page->index << PAGE_CACHE_SHIFT;
    unsigned int data_blocks, ind_blocks, rblocks;
    struct gfs2_holder gh;
    loff_t size;
    int ret;

    sb_start_pagefault(inode->i_sb);

    /* Update file times before taking page lock */
    file_update_time(vma->vm_file);

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

    gfs2_size_hint(vma->vm_file, pos, PAGE_CACHE_SIZE);

    gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
    ret = gfs2_glock_nq(&gh);
    if (ret)
        goto out;

    set_bit(GLF_DIRTY, &ip->i_gl->gl_flags);
    set_bit(GIF_SW_PAGED, &ip->i_flags);

    if (!gfs2_write_alloc_required(ip, pos, PAGE_CACHE_SIZE)) {
        lock_page(page);
        if (!PageUptodate(page) || page->mapping != inode->i_mapping) {
            ret = -EAGAIN;
            unlock_page(page);
        }
        goto out_unlock;
    }

    ret = gfs2_rindex_update(sdp);
    if (ret)
        goto out_unlock;

    ret = gfs2_quota_lock_check(ip);
    if (ret)
        goto out_unlock;
    gfs2_write_calc_reserv(ip, PAGE_CACHE_SIZE, &data_blocks, &ind_blocks);
    ret = gfs2_inplace_reserve(ip, data_blocks + ind_blocks);
    if (ret)
        goto out_quota_unlock;

    rblocks = RES_DINODE + ind_blocks;
    if (gfs2_is_jdata(ip))
        rblocks += data_blocks ? data_blocks : 1;
    if (ind_blocks || data_blocks) {
        rblocks += RES_STATFS + RES_QUOTA;
        rblocks += gfs2_rg_blocks(ip, data_blocks + ind_blocks);
    }
    ret = gfs2_trans_begin(sdp, rblocks, 0);
    if (ret)
        goto out_trans_fail;

    lock_page(page);
    ret = -EINVAL;
    size = i_size_read(inode);
    last_index = (size - 1) >> PAGE_CACHE_SHIFT;
    /* Check page index against inode size */
    if (size == 0 || (page->index > last_index))
        goto out_trans_end;

    ret = -EAGAIN;
    /* If truncated, we must retry the operation, we may have raced
     * with the glock demotion code.
     */
    if (!PageUptodate(page) || page->mapping != inode->i_mapping)
        goto out_trans_end;

    /* Unstuff, if required, and allocate backing blocks for page */
    ret = 0;
    if (gfs2_is_stuffed(ip))
        ret = gfs2_unstuff_dinode(ip, page);
    if (ret == 0)
        ret = gfs2_allocate_page_backing(page);

out_trans_end:
    if (ret)
        unlock_page(page);
    gfs2_trans_end(sdp);
out_trans_fail:
    gfs2_inplace_release(ip);
out_quota_unlock:
    gfs2_quota_unlock(ip);
out_unlock:
    gfs2_glock_dq(&gh);
out:
    gfs2_holder_uninit(&gh);
    if (ret == 0) {
        set_page_dirty(page);
        wait_on_page_writeback(page);
    }
    sb_end_pagefault(inode->i_sb);
    return block_page_mkwrite_return(ret);
}

static const struct vm_operations_struct gfs2_vm_ops = {
    .fault = filemap_fault,
    .page_mkwrite = gfs2_page_mkwrite,
    .remap_pages = generic_file_remap_pages,
};

static int gfs2_mmap(struct file *file, struct vm_area_struct *vma)
{
    struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);

    if (!(file->f_flags & O_NOATIME) &&
        !IS_NOATIME(&ip->i_inode)) {
        struct gfs2_holder i_gh;
        int error;

        error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY,
                       &i_gh);
        if (error)
            return error;
        /* grab lock to update inode */
        gfs2_glock_dq_uninit(&i_gh);
        file_accessed(file);
    }
    vma->vm_ops = &gfs2_vm_ops;

    return 0;
}

static int gfs2_open(struct inode *inode, struct file *file)
{
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_holder i_gh;
    struct gfs2_file *fp;
    int error;

    fp = kzalloc(sizeof(struct gfs2_file), GFP_KERNEL);
    if (!fp)
        return -ENOMEM;

    mutex_init(&fp->f_fl_mutex);

    gfs2_assert_warn(GFS2_SB(inode), !file->private_data);
    file->private_data = fp;

    if (S_ISREG(ip->i_inode.i_mode)) {
        error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY,
                       &i_gh);
        if (error)
            goto fail;

        if (!(file->f_flags & O_LARGEFILE) &&
            i_size_read(inode) > MAX_NON_LFS) {
            error = -EOVERFLOW;
            goto fail_gunlock;
        }

        gfs2_glock_dq_uninit(&i_gh);
    }

    return 0;

fail_gunlock:
    gfs2_glock_dq_uninit(&i_gh);
fail:
    file->private_data = NULL;
    kfree(fp);
    return error;
}

static int gfs2_release(struct inode *inode, struct file *file)
{
    struct gfs2_inode *ip = GFS2_I(inode);

    kfree(file->private_data);
    file->private_data = NULL;

    if ((file->f_mode & FMODE_WRITE) &&
        (atomic_read(&inode->i_writecount) == 1))
        gfs2_rs_delete(ip);

    return 0;
}

static int gfs2_fsync(struct file *file, loff_t start, loff_t end,
              int datasync)
{
    struct address_space *mapping = file->f_mapping;
    struct inode *inode = mapping->host;
    int sync_state = inode->i_state & (I_DIRTY_SYNC|I_DIRTY_DATASYNC);
    struct gfs2_inode *ip = GFS2_I(inode);
    int ret = 0, ret1 = 0;

    if (mapping->nrpages) {
        ret1 = filemap_fdatawrite_range(mapping, start, end);
        if (ret1 == -EIO)
            return ret1;
    }

    if (datasync)
        sync_state &= ~I_DIRTY_SYNC;

    if (sync_state) {
        ret = sync_inode_metadata(inode, 1);
        if (ret)
            return ret;
        if (gfs2_is_jdata(ip))
            filemap_write_and_wait(mapping);
        gfs2_ail_flush(ip->i_gl, 1);
    }

    if (mapping->nrpages)
        ret = filemap_fdatawait_range(mapping, start, end);

    return ret ? ret : ret1;
}

static ssize_t gfs2_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
                   unsigned long nr_segs, loff_t pos)
{
    struct file *file = iocb->ki_filp;
    size_t writesize = iov_length(iov, nr_segs);
    struct dentry *dentry = file->f_dentry;
    struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
    int ret;

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

    gfs2_size_hint(file, pos, writesize);

    if (file->f_flags & O_APPEND) {
        struct gfs2_holder gh;

        ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
        if (ret)
            return ret;
        gfs2_glock_dq_uninit(&gh);
    }

    return generic_file_aio_write(iocb, iov, nr_segs, pos);
}

static int fallocate_chunk(struct inode *inode, loff_t offset, loff_t len,
               int mode)
{
    struct gfs2_inode *ip = GFS2_I(inode);
    struct buffer_head *dibh;
    int error;
    loff_t size = len;
    unsigned int nr_blks;
    sector_t lblock = offset >> inode->i_blkbits;

    error = gfs2_meta_inode_buffer(ip, &dibh);
    if (unlikely(error))
        return error;

    gfs2_trans_add_bh(ip->i_gl, dibh, 1);

    if (gfs2_is_stuffed(ip)) {
        error = gfs2_unstuff_dinode(ip, NULL);
        if (unlikely(error))
            goto out;
    }

    while (len) {
        struct buffer_head bh_map = { .b_state = 0, .b_blocknr = 0 };
        bh_map.b_size = len;
        set_buffer_zeronew(&bh_map);

        error = gfs2_block_map(inode, lblock, &bh_map, 1);
        if (unlikely(error))
            goto out;
        len -= bh_map.b_size;
        nr_blks = bh_map.b_size >> inode->i_blkbits;
        lblock += nr_blks;
        if (!buffer_new(&bh_map))
            continue;
        if (unlikely(!buffer_zeronew(&bh_map))) {
            error = -EIO;
            goto out;
        }
    }
    if (offset + size > inode->i_size && !(mode & FALLOC_FL_KEEP_SIZE))
        i_size_write(inode, offset + size);

    mark_inode_dirty(inode);

out:
    brelse(dibh);
    return error;
}

static void calc_max_reserv(struct gfs2_inode *ip, loff_t max, loff_t *len,
                unsigned int *data_blocks, unsigned int *ind_blocks)
{
    const struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
    unsigned int max_blocks = ip->i_rgd->rd_free_clone;
    unsigned int tmp, max_data = max_blocks - 3 * (sdp->sd_max_height - 1);

    for (tmp = max_data; tmp > sdp->sd_diptrs;) {
        tmp = DIV_ROUND_UP(tmp, sdp->sd_inptrs);
        max_data -= tmp;
    }
    /* This calculation isn't the exact reverse of gfs2_write_calc_reserve,
       so it might end up with fewer data blocks */
    if (max_data <= *data_blocks)
        return;
    *data_blocks = max_data;
    *ind_blocks = max_blocks - max_data;
    *len = ((loff_t)max_data - 3) << sdp->sd_sb.sb_bsize_shift;
    if (*len > max) {
        *len = max;
        gfs2_write_calc_reserv(ip, max, data_blocks, ind_blocks);
    }
}

static long gfs2_fallocate(struct file *file, int mode, loff_t offset,
               loff_t len)
{
    struct inode *inode = file->f_path.dentry->d_inode;
    struct gfs2_sbd *sdp = GFS2_SB(inode);
    struct gfs2_inode *ip = GFS2_I(inode);
    unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
    loff_t bytes, max_bytes;
    int error;
    const loff_t pos = offset;
    const loff_t count = len;
    loff_t bsize_mask = ~((loff_t)sdp->sd_sb.sb_bsize - 1);
    loff_t next = (offset + len - 1) >> sdp->sd_sb.sb_bsize_shift;
    loff_t max_chunk_size = UINT_MAX & bsize_mask;
    next = (next + 1) << sdp->sd_sb.sb_bsize_shift;

    /* We only support the FALLOC_FL_KEEP_SIZE mode */
    if (mode & ~FALLOC_FL_KEEP_SIZE)
        return -EOPNOTSUPP;

    offset &= bsize_mask;

    len = next - offset;
    bytes = sdp->sd_max_rg_data * sdp->sd_sb.sb_bsize / 2;
    if (!bytes)
        bytes = UINT_MAX;
    bytes &= bsize_mask;
    if (bytes == 0)
        bytes = sdp->sd_sb.sb_bsize;

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

    gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh);
    error = gfs2_glock_nq(&ip->i_gh);
    if (unlikely(error))
        goto out_uninit;

    gfs2_size_hint(file, offset, len);

    while (len > 0) {
        if (len < bytes)
            bytes = len;
        if (!gfs2_write_alloc_required(ip, offset, bytes)) {
            len -= bytes;
            offset += bytes;
            continue;
        }
        error = gfs2_quota_lock_check(ip);
        if (error)
            goto out_unlock;

retry:
        gfs2_write_calc_reserv(ip, bytes, &data_blocks, &ind_blocks);

        error = gfs2_inplace_reserve(ip, data_blocks + ind_blocks);
        if (error) {
            if (error == -ENOSPC && bytes > sdp->sd_sb.sb_bsize) {
                bytes >>= 1;
                bytes &= bsize_mask;
                if (bytes == 0)
                    bytes = sdp->sd_sb.sb_bsize;
                goto retry;
            }
            goto out_qunlock;
        }
        max_bytes = bytes;
        calc_max_reserv(ip, (len > max_chunk_size)? max_chunk_size: len,
                &max_bytes, &data_blocks, &ind_blocks);

        rblocks = RES_DINODE + ind_blocks + RES_STATFS + RES_QUOTA +
              RES_RG_HDR + gfs2_rg_blocks(ip, data_blocks + ind_blocks);
        if (gfs2_is_jdata(ip))
            rblocks += data_blocks ? data_blocks : 1;

        error = gfs2_trans_begin(sdp, rblocks,
                     PAGE_CACHE_SIZE/sdp->sd_sb.sb_bsize);
        if (error)
            goto out_trans_fail;

        error = fallocate_chunk(inode, offset, max_bytes, mode);
        gfs2_trans_end(sdp);

        if (error)
            goto out_trans_fail;

        len -= max_bytes;
        offset += max_bytes;
        gfs2_inplace_release(ip);
        gfs2_quota_unlock(ip);
    }

    if (error == 0)
        error = generic_write_sync(file, pos, count);
    goto out_unlock;

out_trans_fail:
    gfs2_inplace_release(ip);
out_qunlock:
    gfs2_quota_unlock(ip);
out_unlock:
    gfs2_glock_dq(&ip->i_gh);
out_uninit:
    gfs2_holder_uninit(&ip->i_gh);
    return error;
}

#ifdef CONFIG_GFS2_FS_LOCKING_DLM

static int gfs2_setlease(struct file *file, long arg, struct file_lock **fl)
{
    return -EINVAL;
}

static int gfs2_lock(struct file *file, int cmd, struct file_lock *fl)
{
    struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
    struct gfs2_sbd *sdp = GFS2_SB(file->f_mapping->host);
    struct lm_lockstruct *ls = &sdp->sd_lockstruct;

    if (!(fl->fl_flags & FL_POSIX))
        return -ENOLCK;
    if (__mandatory_lock(&ip->i_inode) && fl->fl_type != F_UNLCK)
        return -ENOLCK;

    if (cmd == F_CANCELLK) {
        /* Hack: */
        cmd = F_SETLK;
        fl->fl_type = F_UNLCK;
    }
    if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
        return -EIO;
    if (IS_GETLK(cmd))
        return dlm_posix_get(ls->ls_dlm, ip->i_no_addr, file, fl);
    else if (fl->fl_type == F_UNLCK)
        return dlm_posix_unlock(ls->ls_dlm, ip->i_no_addr, file, fl);
    else
        return dlm_posix_lock(ls->ls_dlm, ip->i_no_addr, file, cmd, fl);
}

static int do_flock(struct file *file, int cmd, struct file_lock *fl)
{
    struct gfs2_file *fp = file->private_data;
    struct gfs2_holder *fl_gh = &fp->f_fl_gh;
    struct gfs2_inode *ip = GFS2_I(file->f_path.dentry->d_inode);
    struct gfs2_glock *gl;
    unsigned int state;
    int flags;
    int error = 0;

    state = (fl->fl_type == F_WRLCK) ? LM_ST_EXCLUSIVE : LM_ST_SHARED;
    flags = (IS_SETLKW(cmd) ? 0 : LM_FLAG_TRY) | GL_EXACT | GL_NOCACHE;

    mutex_lock(&fp->f_fl_mutex);

    gl = fl_gh->gh_gl;
    if (gl) {
        if (fl_gh->gh_state == state)
            goto out;
        flock_lock_file_wait(file,
                     &(struct file_lock){.fl_type = F_UNLCK});
        gfs2_glock_dq_wait(fl_gh);
        gfs2_holder_reinit(state, flags, fl_gh);
    } else {
        error = gfs2_glock_get(GFS2_SB(&ip->i_inode), ip->i_no_addr,
                       &gfs2_flock_glops, CREATE, &gl);
        if (error)
            goto out;
        gfs2_holder_init(gl, state, flags, fl_gh);
        gfs2_glock_put(gl);
    }
    error = gfs2_glock_nq(fl_gh);
    if (error) {
        gfs2_holder_uninit(fl_gh);
        if (error == GLR_TRYFAILED)
            error = -EAGAIN;
    } else {
        error = flock_lock_file_wait(file, fl);
        gfs2_assert_warn(GFS2_SB(&ip->i_inode), !error);
    }

out:
    mutex_unlock(&fp->f_fl_mutex);
    return error;
}

static void do_unflock(struct file *file, struct file_lock *fl)
{
    struct gfs2_file *fp = file->private_data;
    struct gfs2_holder *fl_gh = &fp->f_fl_gh;

    mutex_lock(&fp->f_fl_mutex);
    flock_lock_file_wait(file, fl);
    if (fl_gh->gh_gl) {
        gfs2_glock_dq_wait(fl_gh);
        gfs2_holder_uninit(fl_gh);
    }
    mutex_unlock(&fp->f_fl_mutex);
}

static int gfs2_flock(struct file *file, int cmd, struct file_lock *fl)
{
    if (!(fl->fl_flags & FL_FLOCK))
        return -ENOLCK;
    if (fl->fl_type & LOCK_MAND)
        return -EOPNOTSUPP;

    if (fl->fl_type == F_UNLCK) {
        do_unflock(file, fl);
        return 0;
    } else {
        return do_flock(file, cmd, fl);
    }
}

const struct file_operations gfs2_file_fops = {
    .llseek     = gfs2_llseek,
    .read       = do_sync_read,
    .aio_read   = generic_file_aio_read,
    .write      = do_sync_write,
    .aio_write  = gfs2_file_aio_write,
    .unlocked_ioctl = gfs2_ioctl,
    .mmap       = gfs2_mmap,
    .open       = gfs2_open,
    .release    = gfs2_release,
    .fsync      = gfs2_fsync,
    .lock       = gfs2_lock,
    .flock      = gfs2_flock,
    .splice_read    = generic_file_splice_read,
    .splice_write   = generic_file_splice_write,
    .setlease   = gfs2_setlease,
    .fallocate  = gfs2_fallocate,
};

const struct file_operations gfs2_dir_fops = {
    .readdir    = gfs2_readdir,
    .unlocked_ioctl = gfs2_ioctl,
    .open       = gfs2_open,
    .release    = gfs2_release,
    .fsync      = gfs2_fsync,
    .lock       = gfs2_lock,
    .flock      = gfs2_flock,
    .llseek     = default_llseek,
};

#endif /* CONFIG_GFS2_FS_LOCKING_DLM */

const struct file_operations gfs2_file_fops_nolock = {
    .llseek     = gfs2_llseek,
    .read       = do_sync_read,
    .aio_read   = generic_file_aio_read,
    .write      = do_sync_write,
    .aio_write  = gfs2_file_aio_write,
    .unlocked_ioctl = gfs2_ioctl,
    .mmap       = gfs2_mmap,
    .open       = gfs2_open,
    .release    = gfs2_release,
    .fsync      = gfs2_fsync,
    .splice_read    = generic_file_splice_read,
    .splice_write   = generic_file_splice_write,
    .setlease   = generic_setlease,
    .fallocate  = gfs2_fallocate,
};

const struct file_operations gfs2_dir_fops_nolock = {
    .readdir    = gfs2_readdir,
    .unlocked_ioctl = gfs2_ioctl,
    .open       = gfs2_open,
    .release    = gfs2_release,
    .fsync      = gfs2_fsync,
    .llseek     = default_llseek,
};