Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1311 insertions, 0 deletions

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
new file mode 100644
index 000000000..7c69486d5
--- /dev/null
+++ b/fs/gfs2/file.c
@@ -0,0 +1,1311 @@
+/*
+ * 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 <linux/uaccess.h>
+#include <linux/dlm.h>
+#include <linux/dlm_plock.h>
+#include <linux/delay.h>
+#include <linux/backing-dev.h>
+
+#include "gfs2.h"
+#include "incore.h"
+#include "bmap.h"
+#include "aops.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"
+
+/**
+ * gfs2_llseek - seek to a location in a file
+ * @file: the file
+ * @offset: the offset
+ * @whence: Where to seek from (SEEK_SET, SEEK_CUR, or SEEK_END)
+ *
+ * SEEK_END requires the glock for the file because it references the
+ * file's size.
+ *
+ * Returns: The new offset, or errno
+ */
+
+static loff_t gfs2_llseek(struct file *file, loff_t offset, int whence)
+{
+	struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
+	struct gfs2_holder i_gh;
+	loff_t error;
+
+	switch (whence) {
+	case SEEK_END:
+		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY,
+					   &i_gh);
+		if (!error) {
+			error = generic_file_llseek(file, offset, whence);
+			gfs2_glock_dq_uninit(&i_gh);
+		}
+		break;
+
+	case SEEK_DATA:
+		error = gfs2_seek_data(file, offset);
+		break;
+
+	case SEEK_HOLE:
+		error = gfs2_seek_hole(file, offset);
+		break;
+
+	case SEEK_CUR:
+	case SEEK_SET:
+		/*
+		 * These don't reference inode->i_size and don't depend on the
+		 * block mapping, so we don't need the glock.
+		 */
+		error = generic_file_llseek(file, offset, whence);
+		break;
+	default:
+		error = -EINVAL;
+	}
+
+	return error;
+}
+
+/**
+ * gfs2_readdir - Iterator for a directory
+ * @file: The directory to read from
+ * @ctx: What to feed directory entries to
+ *
+ * Returns: errno
+ */
+
+static int gfs2_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct inode *dir = file->f_mapping->host;
+	struct gfs2_inode *dip = GFS2_I(dir);
+	struct gfs2_holder d_gh;
+	int error;
+
+	error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
+	if (error)
+		return error;
+
+	error = gfs2_dir_read(dir, ctx, &file->f_ra);
+
+	gfs2_glock_dq_uninit(&d_gh);
+
+	return error;
+}
+
+/**
+ * fsflag_gfs2flag
+ *
+ * The FS_JOURNAL_DATA_FL flag maps to GFS2_DIF_INHERIT_JDATA for directories,
+ * and to GFS2_DIF_JDATA for non-directories.
+ */
+static struct {
+	u32 fsflag;
+	u32 gfsflag;
+} fsflag_gfs2flag[] = {
+	{FS_SYNC_FL, GFS2_DIF_SYNC},
+	{FS_IMMUTABLE_FL, GFS2_DIF_IMMUTABLE},
+	{FS_APPEND_FL, GFS2_DIF_APPENDONLY},
+	{FS_NOATIME_FL, GFS2_DIF_NOATIME},
+	{FS_INDEX_FL, GFS2_DIF_EXHASH},
+	{FS_TOPDIR_FL, GFS2_DIF_TOPDIR},
+	{FS_JOURNAL_DATA_FL, GFS2_DIF_JDATA | GFS2_DIF_INHERIT_JDATA},
+};
+
+static int gfs2_get_flags(struct file *filp, u32 __user *ptr)
+{
+	struct inode *inode = file_inode(filp);
+	struct gfs2_inode *ip = GFS2_I(inode);
+	struct gfs2_holder gh;
+	int i, error;
+	u32 gfsflags, fsflags = 0;
+
+	gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
+	error = gfs2_glock_nq(&gh);
+	if (error)
+		goto out_uninit;
+
+	gfsflags = ip->i_diskflags;
+	if (S_ISDIR(inode->i_mode))
+		gfsflags &= ~GFS2_DIF_JDATA;
+	else
+		gfsflags &= ~GFS2_DIF_INHERIT_JDATA;
+	for (i = 0; i < ARRAY_SIZE(fsflag_gfs2flag); i++)
+		if (gfsflags & fsflag_gfs2flag[i].gfsflag)
+			fsflags |= fsflag_gfs2flag[i].fsflag;
+
+	if (put_user(fsflags, ptr))
+		error = -EFAULT;
+
+	gfs2_glock_dq(&gh);
+out_uninit:
+	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))
+		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_TOPDIR|			\
+			     GFS2_DIF_INHERIT_JDATA)
+
+/**
+ * do_gfs2_set_flags - set flags on an inode
+ * @filp: file pointer
+ * @reqflags: The flags to set
+ * @mask: Indicates which flags are valid
+ *
+ */
+static int do_gfs2_set_flags(struct file *filp, u32 reqflags, u32 mask)
+{
+	struct inode *inode = file_inode(filp);
+	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 = -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 (new_flags & GFS2_DIF_JDATA)
+			gfs2_log_flush(sdp, ip->i_gl,
+				       GFS2_LOG_HEAD_FLUSH_NORMAL |
+				       GFS2_LFC_SET_FLAGS);
+		error = filemap_fdatawrite(inode->i_mapping);
+		if (error)
+			goto out;
+		error = filemap_fdatawait(inode->i_mapping);
+		if (error)
+			goto out;
+		if (new_flags & GFS2_DIF_JDATA)
+			gfs2_ordered_del_inode(ip);
+	}
+	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;
+	inode->i_ctime = current_time(inode);
+	gfs2_trans_add_meta(ip->i_gl, bh);
+	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 = file_inode(filp);
+	u32 fsflags, gfsflags = 0;
+	u32 mask;
+	int i;
+
+	if (get_user(fsflags, ptr))
+		return -EFAULT;
+
+	for (i = 0; i < ARRAY_SIZE(fsflag_gfs2flag); i++) {
+		if (fsflags & fsflag_gfs2flag[i].fsflag) {
+			fsflags &= ~fsflag_gfs2flag[i].fsflag;
+			gfsflags |= fsflag_gfs2flag[i].gfsflag;
+		}
+	}
+	if (fsflags || gfsflags & ~GFS2_FLAGS_USER_SET)
+		return -EINVAL;
+
+	mask = GFS2_FLAGS_USER_SET;
+	if (S_ISDIR(inode->i_mode)) {
+		mask &= ~GFS2_DIF_JDATA;
+	} else {
+		/* The GFS2_DIF_TOPDIR flag is only valid for directories. */
+		if (gfsflags & GFS2_DIF_TOPDIR)
+			return -EINVAL;
+		mask &= ~(GFS2_DIF_TOPDIR | GFS2_DIF_INHERIT_JDATA);
+	}
+
+	return do_gfs2_set_flags(filp, gfsflags, mask);
+}
+
+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;
+}
+
+/**
+ * gfs2_size_hint - Give a hint to the size of a write request
+ * @filep: The struct file
+ * @offset: The file offset of the write
+ * @size: The length of the write
+ *
+ * When we are about to do a write, this function records the total
+ * write size in order to provide a suitable hint to the lower layers
+ * about how many blocks will be required.
+ *
+ */
+
+static void gfs2_size_hint(struct file *filep, loff_t offset, size_t size)
+{
+	struct inode *inode = file_inode(filep);
+	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);
+
+	if (hint > atomic_read(&ip->i_res.rs_sizehint))
+		atomic_set(&ip->i_res.rs_sizehint, hint);
+}
+
+/**
+ * gfs2_allocate_page_backing - Use bmap to allocate blocks
+ * @page: The (locked) page to allocate backing for
+ *
+ * We try to allocate all the blocks required for the page in
+ * one go. This might fail for various reasons, so we keep
+ * trying until all the blocks to back this page are allocated.
+ * If some of the blocks are already allocated, thats ok too.
+ */
+
+static int gfs2_allocate_page_backing(struct page *page)
+{
+	struct inode *inode = page->mapping->host;
+	struct buffer_head bh;
+	unsigned long size = PAGE_SIZE;
+	u64 lblock = page->index << (PAGE_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;
+}
+
+/**
+ * gfs2_page_mkwrite - Make a shared, mmap()ed, page writable
+ * @vma: The virtual memory area
+ * @vmf: The virtual memory fault containing the page to become writable
+ *
+ * When the page becomes writable, we need to ensure that we have
+ * blocks allocated on disk to back that page.
+ */
+
+static vm_fault_t gfs2_page_mkwrite(struct vm_fault *vmf)
+{
+	struct page *page = vmf->page;
+	struct inode *inode = file_inode(vmf->vma->vm_file);
+	struct gfs2_inode *ip = GFS2_I(inode);
+	struct gfs2_sbd *sdp = GFS2_SB(inode);
+	struct gfs2_alloc_parms ap = { .aflags = 0, };
+	unsigned long last_index;
+	u64 pos = page->index << PAGE_SHIFT;
+	unsigned int data_blocks, ind_blocks, rblocks;
+	struct gfs2_holder gh;
+	loff_t size;
+	int ret;
+
+	sb_start_pagefault(inode->i_sb);
+
+	ret = gfs2_rsqa_alloc(ip);
+	if (ret)
+		goto out;
+
+	gfs2_size_hint(vmf->vma->vm_file, pos, PAGE_SIZE);
+
+	gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
+	ret = gfs2_glock_nq(&gh);
+	if (ret)
+		goto out_uninit;
+
+	/* Update file times before taking page lock */
+	file_update_time(vmf->vma->vm_file);
+
+	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_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;
+
+	gfs2_write_calc_reserv(ip, PAGE_SIZE, &data_blocks, &ind_blocks);
+	ap.target = data_blocks + ind_blocks;
+	ret = gfs2_quota_lock_check(ip, &ap);
+	if (ret)
+		goto out_unlock;
+	ret = gfs2_inplace_reserve(ip, &ap);
+	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_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_uninit:
+	gfs2_holder_uninit(&gh);
+	if (ret == 0) {
+		set_page_dirty(page);
+		wait_for_stable_page(page);
+	}
+out:
+	sb_end_pagefault(inode->i_sb);
+	return block_page_mkwrite_return(ret);
+}
+
+static const struct vm_operations_struct gfs2_vm_ops = {
+	.fault = filemap_fault,
+	.map_pages = filemap_map_pages,
+	.page_mkwrite = gfs2_page_mkwrite,
+};
+
+/**
+ * gfs2_mmap -
+ * @file: The file to map
+ * @vma: The VMA which described the mapping
+ *
+ * There is no need to get a lock here unless we should be updating
+ * atime. We ignore any locking errors since the only consequence is
+ * a missed atime update (which will just be deferred until later).
+ *
+ * Returns: 0
+ */
+
+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;
+}
+
+/**
+ * gfs2_open_common - This is common to open and atomic_open
+ * @inode: The inode being opened
+ * @file: The file being opened
+ *
+ * This maybe called under a glock or not depending upon how it has
+ * been called. We must always be called under a glock for regular
+ * files, however. For other file types, it does not matter whether
+ * we hold the glock or not.
+ *
+ * Returns: Error code or 0 for success
+ */
+
+int gfs2_open_common(struct inode *inode, struct file *file)
+{
+	struct gfs2_file *fp;
+	int ret;
+
+	if (S_ISREG(inode->i_mode)) {
+		ret = generic_file_open(inode, file);
+		if (ret)
+			return ret;
+	}
+
+	fp = kzalloc(sizeof(struct gfs2_file), GFP_NOFS);
+	if (!fp)
+		return -ENOMEM;
+
+	mutex_init(&fp->f_fl_mutex);
+
+	gfs2_assert_warn(GFS2_SB(inode), !file->private_data);
+	file->private_data = fp;
+	return 0;
+}
+
+/**
+ * gfs2_open - open a file
+ * @inode: the inode to open
+ * @file: the struct file for this opening
+ *
+ * After atomic_open, this function is only used for opening files
+ * which are already cached. We must still get the glock for regular
+ * files to ensure that we have the file size uptodate for the large
+ * file check which is in the common code. That is only an issue for
+ * regular files though.
+ *
+ * Returns: errno
+ */
+
+static int gfs2_open(struct inode *inode, struct file *file)
+{
+	struct gfs2_inode *ip = GFS2_I(inode);
+	struct gfs2_holder i_gh;
+	int error;
+	bool need_unlock = false;
+
+	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)
+			return error;
+		need_unlock = true;
+	}
+
+	error = gfs2_open_common(inode, file);
+
+	if (need_unlock)
+		gfs2_glock_dq_uninit(&i_gh);
+
+	return error;
+}
+
+/**
+ * gfs2_release - called to close a struct file
+ * @inode: the inode the struct file belongs to
+ * @file: the struct file being closed
+ *
+ * Returns: errno
+ */
+
+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))
+		return 0;
+
+	gfs2_rsqa_delete(ip, &inode->i_writecount);
+	return 0;
+}
+
+/**
+ * gfs2_fsync - sync the dirty data for a file (across the cluster)
+ * @file: the file that points to the dentry
+ * @start: the start position in the file to sync
+ * @end: the end position in the file to sync
+ * @datasync: set if we can ignore timestamp changes
+ *
+ * We split the data flushing here so that we don't wait for the data
+ * until after we've also sent the metadata to disk. Note that for
+ * data=ordered, we will write & wait for the data at the log flush
+ * stage anyway, so this is unlikely to make much of a difference
+ * except in the data=writeback case.
+ *
+ * If the fdatawrite fails due to any reason except -EIO, we will
+ * continue the remainder of the fsync, although we'll still report
+ * the error at the end. This is to match filemap_write_and_wait_range()
+ * behaviour.
+ *
+ * Returns: errno
+ */
+
+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_ALL;
+	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 (!gfs2_is_jdata(ip))
+		sync_state &= ~I_DIRTY_PAGES;
+	if (datasync)
+		sync_state &= ~(I_DIRTY_SYNC | I_DIRTY_TIME);
+
+	if (sync_state) {
+		ret = sync_inode_metadata(inode, 1);
+		if (ret)
+			return ret;
+		if (gfs2_is_jdata(ip))
+			ret = file_write_and_wait(file);
+		if (ret)
+			return ret;
+		gfs2_ail_flush(ip->i_gl, 1);
+	}
+
+	if (mapping->nrpages)
+		ret = file_fdatawait_range(file, start, end);
+
+	return ret ? ret : ret1;
+}
+
+static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct file *file = iocb->ki_filp;
+	struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
+	size_t count = iov_iter_count(to);
+	struct gfs2_holder gh;
+	ssize_t ret;
+
+	if (!count)
+		return 0; /* skip atime */
+
+	gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh);
+	ret = gfs2_glock_nq(&gh);
+	if (ret)
+		goto out_uninit;
+
+	ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL);
+
+	gfs2_glock_dq(&gh);
+out_uninit:
+	gfs2_holder_uninit(&gh);
+	return ret;
+}
+
+static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file->f_mapping->host;
+	struct gfs2_inode *ip = GFS2_I(inode);
+	size_t len = iov_iter_count(from);
+	loff_t offset = iocb->ki_pos;
+	struct gfs2_holder gh;
+	ssize_t ret;
+
+	/*
+	 * Deferred lock, even if its a write, since we do no allocation on
+	 * this path. All we need to change is the atime, and this lock mode
+	 * ensures that other nodes have flushed their buffered read caches
+	 * (i.e. their page cache entries for this inode). We do not,
+	 * unfortunately, have the option of only flushing a range like the
+	 * VFS does.
+	 */
+	gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh);
+	ret = gfs2_glock_nq(&gh);
+	if (ret)
+		goto out_uninit;
+
+	/* Silently fall back to buffered I/O when writing beyond EOF */
+	if (offset + len > i_size_read(&ip->i_inode))
+		goto out;
+
+	ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL);
+
+out:
+	gfs2_glock_dq(&gh);
+out_uninit:
+	gfs2_holder_uninit(&gh);
+	return ret;
+}
+
+static ssize_t gfs2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	ssize_t ret;
+
+	if (iocb->ki_flags & IOCB_DIRECT) {
+		ret = gfs2_file_direct_read(iocb, to);
+		if (likely(ret != -ENOTBLK))
+			return ret;
+		iocb->ki_flags &= ~IOCB_DIRECT;
+	}
+	return generic_file_read_iter(iocb, to);
+}
+
+/**
+ * gfs2_file_write_iter - Perform a write to a file
+ * @iocb: The io context
+ * @from: The data to write
+ *
+ * We have to do a lock/unlock here to refresh the inode size for
+ * O_APPEND writes, otherwise we can land up writing at the wrong
+ * offset. There is still a race, but provided the app is using its
+ * own file locking, this will make O_APPEND work as expected.
+ *
+ */
+
+static ssize_t gfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file_inode(file);
+	struct gfs2_inode *ip = GFS2_I(inode);
+	ssize_t ret;
+
+	ret = gfs2_rsqa_alloc(ip);
+	if (ret)
+		return ret;
+
+	gfs2_size_hint(file, iocb->ki_pos, iov_iter_count(from));
+
+	if (iocb->ki_flags & IOCB_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);
+	}
+
+	inode_lock(inode);
+	ret = generic_write_checks(iocb, from);
+	if (ret <= 0)
+		goto out_unlock;
+
+	ret = file_remove_privs(file);
+	if (ret)
+		goto out_unlock;
+
+	ret = file_update_time(file);
+	if (ret)
+		goto out_unlock;
+
+	if (iocb->ki_flags & IOCB_DIRECT) {
+		struct address_space *mapping = file->f_mapping;
+		ssize_t buffered, ret2;
+
+		ret = gfs2_file_direct_write(iocb, from);
+		if (ret < 0 || !iov_iter_count(from))
+			goto out_unlock;
+
+		iocb->ki_flags |= IOCB_DSYNC;
+		current->backing_dev_info = inode_to_bdi(inode);
+		buffered = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops);
+		current->backing_dev_info = NULL;
+		if (unlikely(buffered <= 0)) {
+			if (!ret)
+				ret = buffered;
+			goto out_unlock;
+		}
+
+		/*
+		 * We need to ensure that the page cache pages are written to
+		 * disk and invalidated to preserve the expected O_DIRECT
+		 * semantics.  If the writeback or invalidate fails, only report
+		 * the direct I/O range as we don't know if the buffered pages
+		 * made it to disk.
+		 */
+		iocb->ki_pos += buffered;
+		ret2 = generic_write_sync(iocb, buffered);
+		invalidate_mapping_pages(mapping,
+				(iocb->ki_pos - buffered) >> PAGE_SHIFT,
+				(iocb->ki_pos - 1) >> PAGE_SHIFT);
+		if (!ret || ret2 > 0)
+			ret += ret2;
+	} else {
+		current->backing_dev_info = inode_to_bdi(inode);
+		ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops);
+		current->backing_dev_info = NULL;
+		if (likely(ret > 0)) {
+			iocb->ki_pos += ret;
+			ret = generic_write_sync(iocb, ret);
+		}
+	}
+
+out_unlock:
+	inode_unlock(inode);
+	return ret;
+}
+
+static int fallocate_chunk(struct inode *inode, loff_t offset, loff_t len,
+			   int mode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct gfs2_inode *ip = GFS2_I(inode);
+	loff_t end = offset + len;
+	struct buffer_head *dibh;
+	int error;
+
+	error = gfs2_meta_inode_buffer(ip, &dibh);
+	if (unlikely(error))
+		return error;
+
+	gfs2_trans_add_meta(ip->i_gl, dibh);
+
+	if (gfs2_is_stuffed(ip)) {
+		error = gfs2_unstuff_dinode(ip, NULL);
+		if (unlikely(error))
+			goto out;
+	}
+
+	while (offset < end) {
+		struct iomap iomap = { };
+
+		error = gfs2_iomap_get_alloc(inode, offset, end - offset,
+					     &iomap);
+		if (error)
+			goto out;
+		offset = iomap.offset + iomap.length;
+		if (!(iomap.flags & IOMAP_F_NEW))
+			continue;
+		error = sb_issue_zeroout(sb, iomap.addr >> inode->i_blkbits,
+					 iomap.length >> inode->i_blkbits,
+					 GFP_NOFS);
+		if (error) {
+			fs_err(GFS2_SB(inode), "Failed to zero data buffers\n");
+			goto out;
+		}
+	}
+out:
+	brelse(dibh);
+	return error;
+}
+/**
+ * calc_max_reserv() - Reverse of write_calc_reserv. Given a number of
+ *                     blocks, determine how many bytes can be written.
+ * @ip:          The inode in question.
+ * @len:         Max cap of bytes. What we return in *len must be <= this.
+ * @data_blocks: Compute and return the number of data blocks needed
+ * @ind_blocks:  Compute and return the number of indirect blocks needed
+ * @max_blocks:  The total blocks available to work with.
+ *
+ * Returns: void, but @len, @data_blocks and @ind_blocks are filled in.
+ */
+static void calc_max_reserv(struct gfs2_inode *ip, loff_t *len,
+			    unsigned int *data_blocks, unsigned int *ind_blocks,
+			    unsigned int max_blocks)
+{
+	loff_t max = *len;
+	const struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
+	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;
+	}
+
+	*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_inode(file);
+	struct gfs2_sbd *sdp = GFS2_SB(inode);
+	struct gfs2_inode *ip = GFS2_I(inode);
+	struct gfs2_alloc_parms ap = { .aflags = 0, };
+	unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
+	loff_t bytes, max_bytes, max_blks;
+	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;
+
+	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;
+
+	gfs2_size_hint(file, offset, len);
+
+	gfs2_write_calc_reserv(ip, PAGE_SIZE, &data_blocks, &ind_blocks);
+	ap.min_target = data_blocks + ind_blocks;
+
+	while (len > 0) {
+		if (len < bytes)
+			bytes = len;
+		if (!gfs2_write_alloc_required(ip, offset, bytes)) {
+			len -= bytes;
+			offset += bytes;
+			continue;
+		}
+
+		/* We need to determine how many bytes we can actually
+		 * fallocate without exceeding quota or going over the
+		 * end of the fs. We start off optimistically by assuming
+		 * we can write max_bytes */
+		max_bytes = (len > max_chunk_size) ? max_chunk_size : len;
+
+		/* Since max_bytes is most likely a theoretical max, we
+		 * calculate a more realistic 'bytes' to serve as a good
+		 * starting point for the number of bytes we may be able
+		 * to write */
+		gfs2_write_calc_reserv(ip, bytes, &data_blocks, &ind_blocks);
+		ap.target = data_blocks + ind_blocks;
+
+		error = gfs2_quota_lock_check(ip, &ap);
+		if (error)
+			return error;
+		/* ap.allowed tells us how many blocks quota will allow
+		 * us to write. Check if this reduces max_blks */
+		max_blks = UINT_MAX;
+		if (ap.allowed)
+			max_blks = ap.allowed;
+
+		error = gfs2_inplace_reserve(ip, &ap);
+		if (error)
+			goto out_qunlock;
+
+		/* check if the selected rgrp limits our max_blks further */
+		if (ap.allowed && ap.allowed < max_blks)
+			max_blks = ap.allowed;
+
+		/* Almost done. Calculate bytes that can be written using
+		 * max_blks. We also recompute max_bytes, data_blocks and
+		 * ind_blocks */
+		calc_max_reserv(ip, &max_bytes, &data_blocks,
+				&ind_blocks, max_blks);
+
+		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_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 (!(mode & FALLOC_FL_KEEP_SIZE) && (pos + count) > inode->i_size) {
+		i_size_write(inode, pos + count);
+		file_update_time(file);
+		mark_inode_dirty(inode);
+	}
+
+	if ((file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host))
+		return vfs_fsync_range(file, pos, pos + count - 1,
+			       (file->f_flags & __O_SYNC) ? 0 : 1);
+	return 0;
+
+out_trans_fail:
+	gfs2_inplace_release(ip);
+out_qunlock:
+	gfs2_quota_unlock(ip);
+	return error;
+}
+
+static long gfs2_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
+{
+	struct inode *inode = file_inode(file);
+	struct gfs2_sbd *sdp = GFS2_SB(inode);
+	struct gfs2_inode *ip = GFS2_I(inode);
+	struct gfs2_holder gh;
+	int ret;
+
+	if (mode & ~(FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE))
+		return -EOPNOTSUPP;
+	/* fallocate is needed by gfs2_grow to reserve space in the rindex */
+	if (gfs2_is_jdata(ip) && inode != sdp->sd_rindex)
+		return -EOPNOTSUPP;
+
+	inode_lock(inode);
+
+	gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
+	ret = gfs2_glock_nq(&gh);
+	if (ret)
+		goto out_uninit;
+
+	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
+	    (offset + len) > inode->i_size) {
+		ret = inode_newsize_ok(inode, offset + len);
+		if (ret)
+			goto out_unlock;
+	}
+
+	ret = get_write_access(inode);
+	if (ret)
+		goto out_unlock;
+
+	if (mode & FALLOC_FL_PUNCH_HOLE) {
+		ret = __gfs2_punch_hole(file, offset, len);
+	} else {
+		ret = gfs2_rsqa_alloc(ip);
+		if (ret)
+			goto out_putw;
+
+		ret = __gfs2_fallocate(file, mode, offset, len);
+
+		if (ret)
+			gfs2_rs_deltree(&ip->i_res);
+	}
+
+out_putw:
+	put_write_access(inode);
+out_unlock:
+	gfs2_glock_dq(&gh);
+out_uninit:
+	gfs2_holder_uninit(&gh);
+	inode_unlock(inode);
+	return ret;
+}
+
+static ssize_t gfs2_file_splice_write(struct pipe_inode_info *pipe,
+				      struct file *out, loff_t *ppos,
+				      size_t len, unsigned int flags)
+{
+	int error;
+	struct gfs2_inode *ip = GFS2_I(out->f_mapping->host);
+
+	error = gfs2_rsqa_alloc(ip);
+	if (error)
+		return (ssize_t)error;
+
+	gfs2_size_hint(out, *ppos, len);
+
+	return iter_file_splice_write(pipe, out, ppos, len, flags);
+}
+
+#ifdef CONFIG_GFS2_FS_LOCKING_DLM
+
+/**
+ * gfs2_lock - acquire/release a posix lock on a file
+ * @file: the file pointer
+ * @cmd: either modify or retrieve lock state, possibly wait
+ * @fl: type and range of lock
+ *
+ * Returns: errno
+ */
+
+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))) {
+		if (fl->fl_type == F_UNLCK)
+			locks_lock_file_wait(file, fl);
+		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_inode(file));
+	struct gfs2_glock *gl;
+	unsigned int state;
+	u16 flags;
+	int error = 0;
+	int sleeptime;
+
+	state = (fl->fl_type == F_WRLCK) ? LM_ST_EXCLUSIVE : LM_ST_SHARED;
+	flags = (IS_SETLKW(cmd) ? 0 : LM_FLAG_TRY_1CB) | GL_EXACT;
+
+	mutex_lock(&fp->f_fl_mutex);
+
+	if (gfs2_holder_initialized(fl_gh)) {
+		if (fl_gh->gh_state == state)
+			goto out;
+		locks_lock_file_wait(file,
+				     &(struct file_lock) {
+					     .fl_type = F_UNLCK,
+					     .fl_flags = FL_FLOCK
+				     });
+		gfs2_glock_dq(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);
+	}
+	for (sleeptime = 1; sleeptime <= 4; sleeptime <<= 1) {
+		error = gfs2_glock_nq(fl_gh);
+		if (error != GLR_TRYFAILED)
+			break;
+		fl_gh->gh_flags = LM_FLAG_TRY | GL_EXACT;
+		fl_gh->gh_error = 0;
+		msleep(sleeptime);
+	}
+	if (error) {
+		gfs2_holder_uninit(fl_gh);
+		if (error == GLR_TRYFAILED)
+			error = -EAGAIN;
+	} else {
+		error = locks_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);
+	locks_lock_file_wait(file, fl);
+	if (gfs2_holder_initialized(fl_gh)) {
+		gfs2_glock_dq(fl_gh);
+		gfs2_holder_uninit(fl_gh);
+	}
+	mutex_unlock(&fp->f_fl_mutex);
+}
+
+/**
+ * gfs2_flock - acquire/release a flock lock on a file
+ * @file: the file pointer
+ * @cmd: either modify or retrieve lock state, possibly wait
+ * @fl: type and range of lock
+ *
+ * Returns: errno
+ */
+
+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_iter	= gfs2_file_read_iter,
+	.write_iter	= gfs2_file_write_iter,
+	.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	= gfs2_file_splice_write,
+	.setlease	= simple_nosetlease,
+	.fallocate	= gfs2_fallocate,
+};
+
+const struct file_operations gfs2_dir_fops = {
+	.iterate_shared	= 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_iter	= gfs2_file_read_iter,
+	.write_iter	= gfs2_file_write_iter,
+	.unlocked_ioctl	= gfs2_ioctl,
+	.mmap		= gfs2_mmap,
+	.open		= gfs2_open,
+	.release	= gfs2_release,
+	.fsync		= gfs2_fsync,
+	.splice_read	= generic_file_splice_read,
+	.splice_write	= gfs2_file_splice_write,
+	.setlease	= generic_setlease,
+	.fallocate	= gfs2_fallocate,
+};
+
+const struct file_operations gfs2_dir_fops_nolock = {
+	.iterate_shared	= gfs2_readdir,
+	.unlocked_ioctl	= gfs2_ioctl,
+	.open		= gfs2_open,
+	.release	= gfs2_release,
+	.fsync		= gfs2_fsync,
+	.llseek		= default_llseek,
+};
+