提交 d475c634 编写于 作者: M Matthew Wilcox 提交者: Linus Torvalds

dax,ext2: replace XIP read and write with DAX I/O

Use the generic AIO infrastructure instead of custom read and write
methods.  In addition to giving us support for AIO, this adds the missing
locking between read() and truncate().
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>
Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Cc: Andreas Dilger <andreas.dilger@intel.com>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
上级 fbbbad4b
......@@ -3151,6 +3151,12 @@ L: linux-i2c@vger.kernel.org
S: Maintained
F: drivers/i2c/busses/i2c-diolan-u2c.c
DIRECT ACCESS (DAX)
M: Matthew Wilcox <willy@linux.intel.com>
L: linux-fsdevel@vger.kernel.org
S: Supported
F: fs/dax.c
DIRECTORY NOTIFICATION (DNOTIFY)
M: Eric Paris <eparis@parisplace.org>
S: Maintained
......
......@@ -28,6 +28,7 @@ obj-$(CONFIG_SIGNALFD) += signalfd.o
obj-$(CONFIG_TIMERFD) += timerfd.o
obj-$(CONFIG_EVENTFD) += eventfd.o
obj-$(CONFIG_AIO) += aio.o
obj-$(CONFIG_FS_XIP) += dax.o
obj-$(CONFIG_FILE_LOCKING) += locks.o
obj-$(CONFIG_COMPAT) += compat.o compat_ioctl.o
obj-$(CONFIG_BINFMT_AOUT) += binfmt_aout.o
......
/*
* fs/dax.c - Direct Access filesystem code
* Copyright (c) 2013-2014 Intel Corporation
* Author: Matthew Wilcox <matthew.r.wilcox@intel.com>
* Author: Ross Zwisler <ross.zwisler@linux.intel.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*/
#include <linux/atomic.h>
#include <linux/blkdev.h>
#include <linux/buffer_head.h>
#include <linux/fs.h>
#include <linux/genhd.h>
#include <linux/mutex.h>
#include <linux/uio.h>
static long dax_get_addr(struct buffer_head *bh, void **addr, unsigned blkbits)
{
unsigned long pfn;
sector_t sector = bh->b_blocknr << (blkbits - 9);
return bdev_direct_access(bh->b_bdev, sector, addr, &pfn, bh->b_size);
}
static void dax_new_buf(void *addr, unsigned size, unsigned first, loff_t pos,
loff_t end)
{
loff_t final = end - pos + first; /* The final byte of the buffer */
if (first > 0)
memset(addr, 0, first);
if (final < size)
memset(addr + final, 0, size - final);
}
static bool buffer_written(struct buffer_head *bh)
{
return buffer_mapped(bh) && !buffer_unwritten(bh);
}
/*
* When ext4 encounters a hole, it returns without modifying the buffer_head
* which means that we can't trust b_size. To cope with this, we set b_state
* to 0 before calling get_block and, if any bit is set, we know we can trust
* b_size. Unfortunate, really, since ext4 knows precisely how long a hole is
* and would save us time calling get_block repeatedly.
*/
static bool buffer_size_valid(struct buffer_head *bh)
{
return bh->b_state != 0;
}
static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
loff_t start, loff_t end, get_block_t get_block,
struct buffer_head *bh)
{
ssize_t retval = 0;
loff_t pos = start;
loff_t max = start;
loff_t bh_max = start;
void *addr;
bool hole = false;
if (rw != WRITE)
end = min(end, i_size_read(inode));
while (pos < end) {
unsigned len;
if (pos == max) {
unsigned blkbits = inode->i_blkbits;
sector_t block = pos >> blkbits;
unsigned first = pos - (block << blkbits);
long size;
if (pos == bh_max) {
bh->b_size = PAGE_ALIGN(end - pos);
bh->b_state = 0;
retval = get_block(inode, block, bh,
rw == WRITE);
if (retval)
break;
if (!buffer_size_valid(bh))
bh->b_size = 1 << blkbits;
bh_max = pos - first + bh->b_size;
} else {
unsigned done = bh->b_size -
(bh_max - (pos - first));
bh->b_blocknr += done >> blkbits;
bh->b_size -= done;
}
hole = (rw != WRITE) && !buffer_written(bh);
if (hole) {
addr = NULL;
size = bh->b_size - first;
} else {
retval = dax_get_addr(bh, &addr, blkbits);
if (retval < 0)
break;
if (buffer_unwritten(bh) || buffer_new(bh))
dax_new_buf(addr, retval, first, pos,
end);
addr += first;
size = retval - first;
}
max = min(pos + size, end);
}
if (rw == WRITE)
len = copy_from_iter(addr, max - pos, iter);
else if (!hole)
len = copy_to_iter(addr, max - pos, iter);
else
len = iov_iter_zero(max - pos, iter);
if (!len)
break;
pos += len;
addr += len;
}
return (pos == start) ? retval : pos - start;
}
/**
* dax_do_io - Perform I/O to a DAX file
* @rw: READ to read or WRITE to write
* @iocb: The control block for this I/O
* @inode: The file which the I/O is directed at
* @iter: The addresses to do I/O from or to
* @pos: The file offset where the I/O starts
* @get_block: The filesystem method used to translate file offsets to blocks
* @end_io: A filesystem callback for I/O completion
* @flags: See below
*
* This function uses the same locking scheme as do_blockdev_direct_IO:
* If @flags has DIO_LOCKING set, we assume that the i_mutex is held by the
* caller for writes. For reads, we take and release the i_mutex ourselves.
* If DIO_LOCKING is not set, the filesystem takes care of its own locking.
* As with do_blockdev_direct_IO(), we increment i_dio_count while the I/O
* is in progress.
*/
ssize_t dax_do_io(int rw, struct kiocb *iocb, struct inode *inode,
struct iov_iter *iter, loff_t pos,
get_block_t get_block, dio_iodone_t end_io, int flags)
{
struct buffer_head bh;
ssize_t retval = -EINVAL;
loff_t end = pos + iov_iter_count(iter);
memset(&bh, 0, sizeof(bh));
if ((flags & DIO_LOCKING) && (rw == READ)) {
struct address_space *mapping = inode->i_mapping;
mutex_lock(&inode->i_mutex);
retval = filemap_write_and_wait_range(mapping, pos, end - 1);
if (retval) {
mutex_unlock(&inode->i_mutex);
goto out;
}
}
/* Protects against truncate */
atomic_inc(&inode->i_dio_count);
retval = dax_io(rw, inode, iter, pos, end, get_block, &bh);
if ((flags & DIO_LOCKING) && (rw == READ))
mutex_unlock(&inode->i_mutex);
if ((retval > 0) && end_io)
end_io(iocb, pos, retval, bh.b_private);
inode_dio_done(inode);
out:
return retval;
}
EXPORT_SYMBOL_GPL(dax_do_io);
......@@ -81,8 +81,10 @@ const struct file_operations ext2_file_operations = {
#ifdef CONFIG_EXT2_FS_XIP
const struct file_operations ext2_xip_file_operations = {
.llseek = generic_file_llseek,
.read = xip_file_read,
.write = xip_file_write,
.read = new_sync_read,
.write = new_sync_write,
.read_iter = generic_file_read_iter,
.write_iter = generic_file_write_iter,
.unlocked_ioctl = ext2_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = ext2_compat_ioctl,
......
......@@ -859,7 +859,12 @@ ext2_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
size_t count = iov_iter_count(iter);
ssize_t ret;
ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, ext2_get_block);
if (IS_DAX(inode))
ret = dax_do_io(rw, iocb, inode, iter, offset, ext2_get_block,
NULL, DIO_LOCKING);
else
ret = blockdev_direct_IO(rw, iocb, inode, iter, offset,
ext2_get_block);
if (ret < 0 && (rw & WRITE))
ext2_write_failed(mapping, offset + count);
return ret;
......@@ -888,6 +893,7 @@ const struct address_space_operations ext2_aops = {
const struct address_space_operations ext2_aops_xip = {
.bmap = ext2_bmap,
.get_xip_mem = ext2_get_xip_mem,
.direct_IO = ext2_direct_IO,
};
const struct address_space_operations ext2_nobh_aops = {
......
......@@ -2587,12 +2587,11 @@ extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
extern int generic_file_open(struct inode * inode, struct file * filp);
extern int nonseekable_open(struct inode * inode, struct file * filp);
ssize_t dax_do_io(int rw, struct kiocb *, struct inode *, struct iov_iter *,
loff_t, get_block_t, dio_iodone_t, int flags);
#ifdef CONFIG_FS_XIP
extern ssize_t xip_file_read(struct file *filp, char __user *buf, size_t len,
loff_t *ppos);
extern int xip_file_mmap(struct file * file, struct vm_area_struct * vma);
extern ssize_t xip_file_write(struct file *filp, const char __user *buf,
size_t len, loff_t *ppos);
extern int xip_truncate_page(struct address_space *mapping, loff_t from);
#else
static inline int xip_truncate_page(struct address_space *mapping, loff_t from)
......@@ -2756,6 +2755,11 @@ extern int generic_show_options(struct seq_file *m, struct dentry *root);
extern void save_mount_options(struct super_block *sb, char *options);
extern void replace_mount_options(struct super_block *sb, char *options);
static inline bool io_is_direct(struct file *filp)
{
return (filp->f_flags & O_DIRECT) || IS_DAX(file_inode(filp));
}
static inline ino_t parent_ino(struct dentry *dentry)
{
ino_t res;
......
......@@ -1695,8 +1695,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
loff_t *ppos = &iocb->ki_pos;
loff_t pos = *ppos;
/* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
if (file->f_flags & O_DIRECT) {
if (io_is_direct(file)) {
struct address_space *mapping = file->f_mapping;
struct inode *inode = mapping->host;
size_t count = iov_iter_count(iter);
......@@ -2584,8 +2583,7 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (err)
goto out;
/* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
if (unlikely(file->f_flags & O_DIRECT)) {
if (io_is_direct(file)) {
loff_t endbyte;
written = generic_file_direct_write(iocb, from, pos);
......
......@@ -42,119 +42,6 @@ static struct page *xip_sparse_page(void)
return __xip_sparse_page;
}
/*
* This is a file read routine for execute in place files, and uses
* the mapping->a_ops->get_xip_mem() function for the actual low-level
* stuff.
*
* Note the struct file* is not used at all. It may be NULL.
*/
static ssize_t
do_xip_mapping_read(struct address_space *mapping,
struct file_ra_state *_ra,
struct file *filp,
char __user *buf,
size_t len,
loff_t *ppos)
{
struct inode *inode = mapping->host;
pgoff_t index, end_index;
unsigned long offset;
loff_t isize, pos;
size_t copied = 0, error = 0;
BUG_ON(!mapping->a_ops->get_xip_mem);
pos = *ppos;
index = pos >> PAGE_CACHE_SHIFT;
offset = pos & ~PAGE_CACHE_MASK;
isize = i_size_read(inode);
if (!isize)
goto out;
end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
do {
unsigned long nr, left;
void *xip_mem;
unsigned long xip_pfn;
int zero = 0;
/* nr is the maximum number of bytes to copy from this page */
nr = PAGE_CACHE_SIZE;
if (index >= end_index) {
if (index > end_index)
goto out;
nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
if (nr <= offset) {
goto out;
}
}
nr = nr - offset;
if (nr > len - copied)
nr = len - copied;
error = mapping->a_ops->get_xip_mem(mapping, index, 0,
&xip_mem, &xip_pfn);
if (unlikely(error)) {
if (error == -ENODATA) {
/* sparse */
zero = 1;
} else
goto out;
}
/* If users can be writing to this page using arbitrary
* virtual addresses, take care about potential aliasing
* before reading the page on the kernel side.
*/
if (mapping_writably_mapped(mapping))
/* address based flush */ ;
/*
* Ok, we have the mem, so now we can copy it to user space...
*
* The actor routine returns how many bytes were actually used..
* NOTE! This may not be the same as how much of a user buffer
* we filled up (we may be padding etc), so we can only update
* "pos" here (the actor routine has to update the user buffer
* pointers and the remaining count).
*/
if (!zero)
left = __copy_to_user(buf+copied, xip_mem+offset, nr);
else
left = __clear_user(buf + copied, nr);
if (left) {
error = -EFAULT;
goto out;
}
copied += (nr - left);
offset += (nr - left);
index += offset >> PAGE_CACHE_SHIFT;
offset &= ~PAGE_CACHE_MASK;
} while (copied < len);
out:
*ppos = pos + copied;
if (filp)
file_accessed(filp);
return (copied ? copied : error);
}
ssize_t
xip_file_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
{
if (!access_ok(VERIFY_WRITE, buf, len))
return -EFAULT;
return do_xip_mapping_read(filp->f_mapping, &filp->f_ra, filp,
buf, len, ppos);
}
EXPORT_SYMBOL_GPL(xip_file_read);
/*
* __xip_unmap is invoked from xip_unmap and xip_write
*
......@@ -341,127 +228,6 @@ int xip_file_mmap(struct file * file, struct vm_area_struct * vma)
}
EXPORT_SYMBOL_GPL(xip_file_mmap);
static ssize_t
__xip_file_write(struct file *filp, const char __user *buf,
size_t count, loff_t pos, loff_t *ppos)
{
struct address_space * mapping = filp->f_mapping;
const struct address_space_operations *a_ops = mapping->a_ops;
struct inode *inode = mapping->host;
long status = 0;
size_t bytes;
ssize_t written = 0;
BUG_ON(!mapping->a_ops->get_xip_mem);
do {
unsigned long index;
unsigned long offset;
size_t copied;
void *xip_mem;
unsigned long xip_pfn;
offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
index = pos >> PAGE_CACHE_SHIFT;
bytes = PAGE_CACHE_SIZE - offset;
if (bytes > count)
bytes = count;
status = a_ops->get_xip_mem(mapping, index, 0,
&xip_mem, &xip_pfn);
if (status == -ENODATA) {
/* we allocate a new page unmap it */
mutex_lock(&xip_sparse_mutex);
status = a_ops->get_xip_mem(mapping, index, 1,
&xip_mem, &xip_pfn);
mutex_unlock(&xip_sparse_mutex);
if (!status)
/* unmap page at pgoff from all other vmas */
__xip_unmap(mapping, index);
}
if (status)
break;
copied = bytes -
__copy_from_user_nocache(xip_mem + offset, buf, bytes);
if (likely(copied > 0)) {
status = copied;
if (status >= 0) {
written += status;
count -= status;
pos += status;
buf += status;
}
}
if (unlikely(copied != bytes))
if (status >= 0)
status = -EFAULT;
if (status < 0)
break;
} while (count);
*ppos = pos;
/*
* No need to use i_size_read() here, the i_size
* cannot change under us because we hold i_mutex.
*/
if (pos > inode->i_size) {
i_size_write(inode, pos);
mark_inode_dirty(inode);
}
return written ? written : status;
}
ssize_t
xip_file_write(struct file *filp, const char __user *buf, size_t len,
loff_t *ppos)
{
struct address_space *mapping = filp->f_mapping;
struct inode *inode = mapping->host;
size_t count;
loff_t pos;
ssize_t ret;
mutex_lock(&inode->i_mutex);
if (!access_ok(VERIFY_READ, buf, len)) {
ret=-EFAULT;
goto out_up;
}
pos = *ppos;
count = len;
/* We can write back this queue in page reclaim */
current->backing_dev_info = inode_to_bdi(inode);
ret = generic_write_checks(filp, &pos, &count, S_ISBLK(inode->i_mode));
if (ret)
goto out_backing;
if (count == 0)
goto out_backing;
ret = file_remove_suid(filp);
if (ret)
goto out_backing;
ret = file_update_time(filp);
if (ret)
goto out_backing;
ret = __xip_file_write (filp, buf, count, pos, ppos);
out_backing:
current->backing_dev_info = NULL;
out_up:
mutex_unlock(&inode->i_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(xip_file_write);
/*
* truncate a page used for execute in place
* functionality is analog to block_truncate_page but does use get_xip_mem
......
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