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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*/
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/compat.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/filelock.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 <linux/fileattr.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;
}
/*
* struct 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 inline u32 gfs2_gfsflags_to_fsflags(struct inode *inode, u32 gfsflags)
{
int i;
u32 fsflags = 0;
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;
return fsflags;
}
int gfs2_fileattr_get(struct dentry *dentry, struct fileattr *fa)
{
struct inode *inode = d_inode(dentry);
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_holder gh;
int error;
u32 fsflags;
if (d_is_special(dentry))
return -ENOTTY;
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
error = gfs2_glock_nq(&gh);
if (error)
goto out_uninit;
fsflags = gfs2_gfsflags_to_fsflags(inode, ip->i_diskflags);
fileattr_fill_flags(fa, fsflags);
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
* @inode: The inode
* @reqflags: The flags to set
* @mask: Indicates which flags are valid
*
*/
static int do_gfs2_set_flags(struct inode *inode, u32 reqflags, u32 mask)
{
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 = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
if (error)
return error;
error = 0;
flags = ip->i_diskflags;
new_flags = (flags & ~mask) | (reqflags & mask);
if ((new_flags ^ flags) == 0)
goto out;
if (!IS_IMMUTABLE(inode)) {
error = gfs2_permission(&nop_mnt_idmap, 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_set_ctime_current(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);
return error;
}
int gfs2_fileattr_set(struct mnt_idmap *idmap,
struct dentry *dentry, struct fileattr *fa)
{
struct inode *inode = d_inode(dentry);
u32 fsflags = fa->flags, gfsflags = 0;
u32 mask;
int i;
if (d_is_special(dentry))
return -ENOTTY;
if (fileattr_has_fsx(fa))
return -EOPNOTSUPP;
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(inode, gfsflags, mask);
}
static int gfs2_getlabel(struct file *filp, char __user *label)
{
struct inode *inode = file_inode(filp);
struct gfs2_sbd *sdp = GFS2_SB(inode);
if (copy_to_user(label, sdp->sd_sb.sb_locktable, GFS2_LOCKNAME_LEN))
return -EFAULT;
return 0;
}
static long gfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
switch(cmd) {
case FITRIM:
return gfs2_fitrim(filp, (void __user *)arg);
case FS_IOC_GETFSLABEL:
return gfs2_getlabel(filp, (char __user *)arg);
}
return -ENOTTY;
}
#ifdef CONFIG_COMPAT
static long gfs2_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
switch(cmd) {
/* Keep this list in sync with gfs2_ioctl */
case FITRIM:
case FS_IOC_GETFSLABEL:
break;
default:
return -ENOIOCTLCMD;
}
return gfs2_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
}
#else
#define gfs2_compat_ioctl NULL
#endif
/**
* 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_sizehint))
atomic_set(&ip->i_sizehint, hint);
}
/**
* gfs2_allocate_page_backing - Allocate blocks for a write fault
* @page: The (locked) page to allocate backing for
* @length: Size of the allocation
*
* 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,
* that is ok too.
*/
static int gfs2_allocate_page_backing(struct page *page, unsigned int length)
{
u64 pos = page_offset(page);
do {
struct iomap iomap = { };
if (gfs2_iomap_alloc(page->mapping->host, pos, length, &iomap))
return -EIO;
if (length < iomap.length)
iomap.length = length;
length -= iomap.length;
pos += iomap.length;
} while (length > 0);
return 0;
}
/**
* gfs2_page_mkwrite - Make a shared, mmap()ed, page writable
* @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 = {};
u64 offset = page_offset(page);
unsigned int data_blocks, ind_blocks, rblocks;
vm_fault_t ret = VM_FAULT_LOCKED;
struct gfs2_holder gh;
unsigned int length;
loff_t size;
int err;
sb_start_pagefault(inode->i_sb);
gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
err = gfs2_glock_nq(&gh);
if (err) {
ret = vmf_fs_error(err);
goto out_uninit;
}
/* Check page index against inode size */
size = i_size_read(inode);
if (offset >= size) {
ret = VM_FAULT_SIGBUS;
goto out_unlock;
}
/* Update file times before taking page lock */
file_update_time(vmf->vma->vm_file);
/* page is wholly or partially inside EOF */
if (size - offset < PAGE_SIZE)
length = size - offset;
else
length = PAGE_SIZE;
gfs2_size_hint(vmf->vma->vm_file, offset, length);
set_bit(GLF_DIRTY, &ip->i_gl->gl_flags);
set_bit(GIF_SW_PAGED, &ip->i_flags);
/*
* iomap_writepage / iomap_writepages currently don't support inline
* files, so always unstuff here.
*/
if (!gfs2_is_stuffed(ip) &&
!gfs2_write_alloc_required(ip, offset, length)) {
lock_page(page);
if (!PageUptodate(page) || page->mapping != inode->i_mapping) {
ret = VM_FAULT_NOPAGE;
unlock_page(page);
}
goto out_unlock;
}
err = gfs2_rindex_update(sdp);
if (err) {
ret = vmf_fs_error(err);
goto out_unlock;
}
gfs2_write_calc_reserv(ip, length, &data_blocks, &ind_blocks);
ap.target = data_blocks + ind_blocks;
err = gfs2_quota_lock_check(ip, &ap);
if (err) {
ret = vmf_fs_error(err);
goto out_unlock;
}
err = gfs2_inplace_reserve(ip, &ap);
if (err) {
ret = vmf_fs_error(err);
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);
}
err = gfs2_trans_begin(sdp, rblocks, 0);
if (err) {
ret = vmf_fs_error(err);
goto out_trans_fail;
}
/* Unstuff, if required, and allocate backing blocks for page */
if (gfs2_is_stuffed(ip)) {
err = gfs2_unstuff_dinode(ip);
if (err) {
ret = vmf_fs_error(err);
goto out_trans_end;
}
}
lock_page(page);
/* If truncated, we must retry the operation, we may have raced
* with the glock demotion code.
*/
if (!PageUptodate(page) || page->mapping != inode->i_mapping) {
ret = VM_FAULT_NOPAGE;
goto out_page_locked;
}
err = gfs2_allocate_page_backing(page, length);
if (err)
ret = vmf_fs_error(err);
out_page_locked:
if (ret != VM_FAULT_LOCKED)
unlock_page(page);
out_trans_end:
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 == VM_FAULT_LOCKED) {
set_page_dirty(page);
wait_for_stable_page(page);
}
sb_end_pagefault(inode->i_sb);
return ret;
}
static vm_fault_t gfs2_fault(struct vm_fault *vmf)
{
struct inode *inode = file_inode(vmf->vma->vm_file);
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_holder gh;
vm_fault_t ret;
int err;
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
err = gfs2_glock_nq(&gh);
if (err) {
ret = vmf_fs_error(err);
goto out_uninit;
}
ret = filemap_fault(vmf);
gfs2_glock_dq(&gh);
out_uninit:
gfs2_holder_uninit(&gh);
return ret;
}
static const struct vm_operations_struct gfs2_vm_ops = {
.fault = gfs2_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;
if (!gfs2_is_jdata(GFS2_I(inode)))
file->f_mode |= FMODE_CAN_ODIRECT;
}
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;
if (file->f_mode & FMODE_WRITE) {
ret = gfs2_qa_get(GFS2_I(inode));
if (ret)
goto fail;
}
return 0;
fail:
kfree(file->private_data);
file->private_data = NULL;
return ret;
}
/**
* 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) {
if (gfs2_rs_active(&ip->i_res))
gfs2_rs_delete(ip);
gfs2_qa_put(ip);
}
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;
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;
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 inline bool should_fault_in_pages(struct iov_iter *i,
struct kiocb *iocb,
size_t *prev_count,
size_t *window_size)
{
size_t count = iov_iter_count(i);
size_t size, offs;
if (!count)
return false;
if (!user_backed_iter(i))
return false;
/*
* Try to fault in multiple pages initially. When that doesn't result
* in any progress, fall back to a single page.
*/
size = PAGE_SIZE;
offs = offset_in_page(iocb->ki_pos);
if (*prev_count != count) {
size_t nr_dirtied;
nr_dirtied = max(current->nr_dirtied_pause -
current->nr_dirtied, 8);
size = min_t(size_t, SZ_1M, nr_dirtied << PAGE_SHIFT);
}
*prev_count = count;
*window_size = size - offs;
return true;
}
static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to,
struct gfs2_holder *gh)
{
struct file *file = iocb->ki_filp;
struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
size_t prev_count = 0, window_size = 0;
size_t read = 0;
ssize_t ret;
/*
* In this function, we disable page faults when we're holding the
* inode glock while doing I/O. If a page fault occurs, we indicate
* that the inode glock may be dropped, fault in the pages manually,
* and retry.
*
* Unlike generic_file_read_iter, for reads, iomap_dio_rw can trigger
* physical as well as manual page faults, and we need to disable both
* kinds.
*
* For direct I/O, gfs2 takes the inode glock in deferred mode. This
* locking mode is compatible with other deferred holders, so multiple
* processes and nodes can do direct I/O to a file at the same time.
* There's no guarantee that reads or writes will be atomic. Any
* coordination among readers and writers needs to happen externally.
*/
if (!iov_iter_count(to))
return 0; /* skip atime */
gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, gh);
retry:
ret = gfs2_glock_nq(gh);
if (ret)
goto out_uninit;
pagefault_disable();
to->nofault = true;
ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL,
IOMAP_DIO_PARTIAL, NULL, read);
to->nofault = false;
pagefault_enable();
if (ret <= 0 && ret != -EFAULT)
goto out_unlock;
/* No increment (+=) because iomap_dio_rw returns a cumulative value. */
if (ret > 0)
read = ret;
if (should_fault_in_pages(to, iocb, &prev_count, &window_size)) {
gfs2_glock_dq(gh);
window_size -= fault_in_iov_iter_writeable(to, window_size);
if (window_size)
goto retry;
}
out_unlock:
if (gfs2_holder_queued(gh))
gfs2_glock_dq(gh);
out_uninit:
gfs2_holder_uninit(gh);
/* User space doesn't expect partial success. */
if (ret < 0)
return ret;
return read;
}
static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from,
struct gfs2_holder *gh)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
size_t prev_count = 0, window_size = 0;
size_t written = 0;
bool enough_retries;
ssize_t ret;
/*
* In this function, we disable page faults when we're holding the
* inode glock while doing I/O. If a page fault occurs, we indicate
* that the inode glock may be dropped, fault in the pages manually,
* and retry.
*
* For writes, iomap_dio_rw only triggers manual page faults, so we
* don't need to disable physical ones.
*/
/*
* 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);
retry:
ret = gfs2_glock_nq(gh);
if (ret)
goto out_uninit;
/* Silently fall back to buffered I/O when writing beyond EOF */
if (iocb->ki_pos + iov_iter_count(from) > i_size_read(&ip->i_inode))
goto out_unlock;
from->nofault = true;
ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL,
IOMAP_DIO_PARTIAL, NULL, written);
from->nofault = false;
if (ret <= 0) {
if (ret == -ENOTBLK)
ret = 0;
if (ret != -EFAULT)
goto out_unlock;
}
/* No increment (+=) because iomap_dio_rw returns a cumulative value. */
if (ret > 0)
written = ret;
enough_retries = prev_count == iov_iter_count(from) &&
window_size <= PAGE_SIZE;
if (should_fault_in_pages(from, iocb, &prev_count, &window_size)) {
gfs2_glock_dq(gh);
window_size -= fault_in_iov_iter_readable(from, window_size);
if (window_size) {
if (!enough_retries)
goto retry;
/* fall back to buffered I/O */
ret = 0;
}
}
out_unlock:
if (gfs2_holder_queued(gh))
gfs2_glock_dq(gh);
out_uninit:
gfs2_holder_uninit(gh);
/* User space doesn't expect partial success. */
if (ret < 0)
return ret;
return written;
}
static ssize_t gfs2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct gfs2_inode *ip;
struct gfs2_holder gh;
size_t prev_count = 0, window_size = 0;
size_t read = 0;
ssize_t ret;
/*
* In this function, we disable page faults when we're holding the
* inode glock while doing I/O. If a page fault occurs, we indicate
* that the inode glock may be dropped, fault in the pages manually,
* and retry.
*/
if (iocb->ki_flags & IOCB_DIRECT)
return gfs2_file_direct_read(iocb, to, &gh);
pagefault_disable();
iocb->ki_flags |= IOCB_NOIO;
ret = generic_file_read_iter(iocb, to);
iocb->ki_flags &= ~IOCB_NOIO;
pagefault_enable();
if (ret >= 0) {
if (!iov_iter_count(to))
return ret;
read = ret;
} else if (ret != -EFAULT) {
if (ret != -EAGAIN)
return ret;
if (iocb->ki_flags & IOCB_NOWAIT)
return ret;
}
ip = GFS2_I(iocb->ki_filp->f_mapping->host);
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
retry:
ret = gfs2_glock_nq(&gh);
if (ret)
goto out_uninit;
pagefault_disable();
ret = generic_file_read_iter(iocb, to);
pagefault_enable();
if (ret <= 0 && ret != -EFAULT)
goto out_unlock;
if (ret > 0)
read += ret;
if (should_fault_in_pages(to, iocb, &prev_count, &window_size)) {
gfs2_glock_dq(&gh);
window_size -= fault_in_iov_iter_writeable(to, window_size);
if (window_size)
goto retry;
}
out_unlock: