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Revert "btrfs: split btrfs_direct_IO to read and write part"
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This reverts commit d8f3e73.

The patch is a cleanup of direct IO port to iomap infrastructure,
which gets reverted.

Signed-off-by: David Sterba <dsterba@suse.com>
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David Sterba committed Jun 9, 2020
1 parent 2166e5e commit f4c48b4
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Showing 3 changed files with 90 additions and 83 deletions.
3 changes: 0 additions & 3 deletions fs/btrfs/ctree.h
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,6 @@
#include <linux/dynamic_debug.h>
#include <linux/refcount.h>
#include <linux/crc32c.h>
#include <linux/iomap.h>
#include "extent-io-tree.h"
#include "extent_io.h"
#include "extent_map.h"
Expand Down Expand Up @@ -2935,8 +2934,6 @@ void btrfs_writepage_endio_finish_ordered(struct page *page, u64 start,
u64 end, int uptodate);
extern const struct dentry_operations btrfs_dentry_operations;
ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
extern const struct iomap_ops btrfs_dio_iomap_ops;
extern const struct iomap_dio_ops btrfs_dops;

/* ioctl.c */
long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
Expand Down
88 changes: 10 additions & 78 deletions fs/btrfs/file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1809,61 +1809,21 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
return num_written ? num_written : ret;
}

static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
const struct iov_iter *iter, loff_t offset)
{
const unsigned int blocksize_mask = fs_info->sectorsize - 1;

if (offset & blocksize_mask)
return -EINVAL;

if (iov_iter_alignment(iter) & blocksize_mask)
return -EINVAL;

return 0;
}

static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
static ssize_t __btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
loff_t pos = iocb->ki_pos;
ssize_t written = 0;
loff_t pos;
ssize_t written;
ssize_t written_buffered;
loff_t endbyte;
int err;
size_t count = 0;
bool relock = false;

if (check_direct_IO(fs_info, from, pos))
goto buffered;

count = iov_iter_count(from);
/*
* If the write DIO is beyond the EOF, we need update the isize, but it
* is protected by i_mutex. So we can not unlock the i_mutex at this
* case.
*/
if (pos + count <= inode->i_size) {
inode_unlock(inode);
relock = true;
} else if (iocb->ki_flags & IOCB_NOWAIT) {
return -EAGAIN;
}

down_read(&BTRFS_I(inode)->dio_sem);
written = iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops, &btrfs_dops,
is_sync_kiocb(iocb));
up_read(&BTRFS_I(inode)->dio_sem);

if (relock)
inode_lock(inode);
written = btrfs_direct_IO(iocb, from);

if (written < 0 || !iov_iter_count(from))
return written;

buffered:
pos = iocb->ki_pos;
written_buffered = btrfs_buffered_write(iocb, from);
if (written_buffered < 0) {
Expand Down Expand Up @@ -2002,7 +1962,7 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
atomic_inc(&BTRFS_I(inode)->sync_writers);

if (iocb->ki_flags & IOCB_DIRECT) {
num_written = btrfs_direct_write(iocb, from);
num_written = __btrfs_direct_write(iocb, from);
} else {
num_written = btrfs_buffered_write(iocb, from);
if (num_written > 0)
Expand Down Expand Up @@ -3516,44 +3476,16 @@ static int btrfs_file_open(struct inode *inode, struct file *filp)
return generic_file_open(inode, filp);
}

static int check_direct_read(struct btrfs_fs_info *fs_info,
const struct iov_iter *iter, loff_t offset)
{
int ret;
int i, seg;

ret = check_direct_IO(fs_info, iter, offset);
if (ret < 0)
return ret;

for (seg = 0; seg < iter->nr_segs; seg++)
for (i = seg + 1; i < iter->nr_segs; i++)
if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
return -EINVAL;
return 0;
}

static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)
{
struct inode *inode = file_inode(iocb->ki_filp);
ssize_t ret;

if (check_direct_read(btrfs_sb(inode->i_sb), to, iocb->ki_pos))
return 0;

inode_lock_shared(inode);
ret = iomap_dio_rw(iocb, to, &btrfs_dio_iomap_ops, &btrfs_dops,
is_sync_kiocb(iocb));
inode_unlock_shared(inode);
return ret;
}

static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
ssize_t ret = 0;

if (iocb->ki_flags & IOCB_DIRECT) {
ret = btrfs_direct_read(iocb, to);
struct inode *inode = file_inode(iocb->ki_filp);

inode_lock_shared(inode);
ret = btrfs_direct_IO(iocb, to);
inode_unlock_shared(inode);
if (ret < 0)
return ret;
}
Expand Down
82 changes: 80 additions & 2 deletions fs/btrfs/inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@
#include <linux/swap.h>
#include <linux/migrate.h>
#include <linux/sched/mm.h>
#include <linux/iomap.h>
#include <asm/unaligned.h>
#include "misc.h"
#include "ctree.h"
Expand Down Expand Up @@ -7819,15 +7820,92 @@ static blk_qc_t btrfs_submit_direct(struct inode *inode, struct iomap *iomap,
return BLK_QC_T_NONE;
}

const struct iomap_ops btrfs_dio_iomap_ops = {
static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
const struct iov_iter *iter, loff_t offset)
{
int seg;
int i;
unsigned int blocksize_mask = fs_info->sectorsize - 1;
ssize_t retval = -EINVAL;

if (offset & blocksize_mask)
goto out;

if (iov_iter_alignment(iter) & blocksize_mask)
goto out;

/* If this is a write we don't need to check anymore */
if (iov_iter_rw(iter) != READ || !iter_is_iovec(iter))
return 0;
/*
* Check to make sure we don't have duplicate iov_base's in this
* iovec, if so return EINVAL, otherwise we'll get csum errors
* when reading back.
*/
for (seg = 0; seg < iter->nr_segs; seg++) {
for (i = seg + 1; i < iter->nr_segs; i++) {
if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
goto out;
}
}
retval = 0;
out:
return retval;
}

static const struct iomap_ops btrfs_dio_iomap_ops = {
.iomap_begin = btrfs_dio_iomap_begin,
.iomap_end = btrfs_dio_iomap_end,
};

const struct iomap_dio_ops btrfs_dops = {
static const struct iomap_dio_ops btrfs_dops = {
.submit_io = btrfs_submit_direct,
};

ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct extent_changeset *data_reserved = NULL;
loff_t offset = iocb->ki_pos;
size_t count = 0;
bool relock = false;
ssize_t ret;

if (check_direct_IO(fs_info, iter, offset))
return 0;

count = iov_iter_count(iter);
if (iov_iter_rw(iter) == WRITE) {
/*
* If the write DIO is beyond the EOF, we need update
* the isize, but it is protected by i_mutex. So we can
* not unlock the i_mutex at this case.
*/
if (offset + count <= inode->i_size) {
inode_unlock(inode);
relock = true;
} else if (iocb->ki_flags & IOCB_NOWAIT) {
ret = -EAGAIN;
goto out;
}
down_read(&BTRFS_I(inode)->dio_sem);
}

ret = iomap_dio_rw(iocb, iter, &btrfs_dio_iomap_ops, &btrfs_dops,
is_sync_kiocb(iocb));

if (iov_iter_rw(iter) == WRITE) {
up_read(&BTRFS_I(inode)->dio_sem);
}
out:
if (relock)
inode_lock(inode);
extent_changeset_free(data_reserved);
return ret;
}

#define BTRFS_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC)

static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
Expand Down

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