Contributors: 46
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Christoph Hellwig |
2394 |
58.94% |
39 |
25.00% |
| Pavel Begunkov |
320 |
7.88% |
9 |
5.77% |
| Jens Axboe |
225 |
5.54% |
12 |
7.69% |
| Darrick J. Wong |
195 |
4.80% |
1 |
0.64% |
| John Garry |
119 |
2.93% |
2 |
1.28% |
| Al Viro |
90 |
2.22% |
13 |
8.33% |
| Linus Torvalds |
67 |
1.65% |
6 |
3.85% |
| Andrew Morton |
53 |
1.30% |
10 |
6.41% |
| Christian Brauner |
53 |
1.30% |
3 |
1.92% |
| Linus Torvalds (pre-git) |
52 |
1.28% |
11 |
7.05% |
| Matthew Wilcox |
52 |
1.28% |
8 |
5.13% |
| Jan Kara |
49 |
1.21% |
4 |
2.56% |
| Loic Poulain |
47 |
1.16% |
1 |
0.64% |
| Ilya Dryomov |
47 |
1.16% |
1 |
0.64% |
| Bart Van Assche |
46 |
1.13% |
2 |
1.28% |
| Ming Lei |
36 |
0.89% |
2 |
1.28% |
| yangerkun |
28 |
0.69% |
1 |
0.64% |
| Mike Snitzer |
26 |
0.64% |
1 |
0.64% |
| Keith Busch |
24 |
0.59% |
2 |
1.28% |
| Dan J Williams |
20 |
0.49% |
1 |
0.64% |
| Rafael J. Wysocki |
18 |
0.44% |
1 |
0.64% |
| Adam Manzanares |
12 |
0.30% |
1 |
0.64% |
| Andi Kleen |
10 |
0.25% |
1 |
0.64% |
| Li Nan |
10 |
0.25% |
1 |
0.64% |
| Jianpeng Ma |
6 |
0.15% |
1 |
0.64% |
| Ingo Molnar |
6 |
0.15% |
1 |
0.64% |
| Akinobu Mita |
5 |
0.12% |
1 |
0.64% |
| Sarthak Kukreti |
5 |
0.12% |
1 |
0.64% |
| Peter Zijlstra |
5 |
0.12% |
1 |
0.64% |
| Miklos Szeredi |
4 |
0.10% |
1 |
0.64% |
| Logan Gunthorpe |
4 |
0.10% |
1 |
0.64% |
| Nicholas Piggin |
4 |
0.10% |
1 |
0.64% |
| David Howells |
4 |
0.10% |
2 |
1.28% |
| Kenneth W Chen |
3 |
0.07% |
1 |
0.64% |
| Chaitanya Kulkarni |
3 |
0.07% |
1 |
0.64% |
| Domenico Andreoli |
3 |
0.07% |
1 |
0.64% |
| Amit Arora |
3 |
0.07% |
1 |
0.64% |
| Jakub Kiciński |
3 |
0.07% |
1 |
0.64% |
| Mel Gorman |
3 |
0.07% |
1 |
0.64% |
| Jeff Layton |
2 |
0.05% |
1 |
0.64% |
| Arjan van de Ven |
1 |
0.02% |
1 |
0.64% |
| Tejun Heo |
1 |
0.02% |
1 |
0.64% |
| Lei Ming |
1 |
0.02% |
1 |
0.64% |
| Arnd Bergmann |
1 |
0.02% |
1 |
0.64% |
| Thomas Gleixner |
1 |
0.02% |
1 |
0.64% |
| Andreas Gruenbacher |
1 |
0.02% |
1 |
0.64% |
| Total |
4062 |
|
156 |
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
* Copyright (C) 2016 - 2020 Christoph Hellwig
*/
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/blkdev.h>
#include <linux/buffer_head.h>
#include <linux/mpage.h>
#include <linux/uio.h>
#include <linux/namei.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/falloc.h>
#include <linux/suspend.h>
#include <linux/fs.h>
#include <linux/iomap.h>
#include <linux/module.h>
#include "blk.h"
static inline struct inode *bdev_file_inode(struct file *file)
{
return file->f_mapping->host;
}
static blk_opf_t dio_bio_write_op(struct kiocb *iocb)
{
blk_opf_t opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
/* avoid the need for a I/O completion work item */
if (iocb_is_dsync(iocb))
opf |= REQ_FUA;
return opf;
}
static bool blkdev_dio_invalid(struct block_device *bdev, loff_t pos,
struct iov_iter *iter, bool is_atomic)
{
if (is_atomic && !generic_atomic_write_valid(iter, pos))
return true;
return pos & (bdev_logical_block_size(bdev) - 1) ||
!bdev_iter_is_aligned(bdev, iter);
}
#define DIO_INLINE_BIO_VECS 4
static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
struct iov_iter *iter, struct block_device *bdev,
unsigned int nr_pages)
{
struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs;
loff_t pos = iocb->ki_pos;
bool should_dirty = false;
struct bio bio;
ssize_t ret;
if (nr_pages <= DIO_INLINE_BIO_VECS)
vecs = inline_vecs;
else {
vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec),
GFP_KERNEL);
if (!vecs)
return -ENOMEM;
}
if (iov_iter_rw(iter) == READ) {
bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ);
if (user_backed_iter(iter))
should_dirty = true;
} else {
bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb));
}
bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT;
bio.bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
bio.bi_ioprio = iocb->ki_ioprio;
if (iocb->ki_flags & IOCB_ATOMIC)
bio.bi_opf |= REQ_ATOMIC;
ret = bio_iov_iter_get_pages(&bio, iter);
if (unlikely(ret))
goto out;
ret = bio.bi_iter.bi_size;
if (iov_iter_rw(iter) == WRITE)
task_io_account_write(ret);
if (iocb->ki_flags & IOCB_NOWAIT)
bio.bi_opf |= REQ_NOWAIT;
submit_bio_wait(&bio);
bio_release_pages(&bio, should_dirty);
if (unlikely(bio.bi_status))
ret = blk_status_to_errno(bio.bi_status);
out:
if (vecs != inline_vecs)
kfree(vecs);
bio_uninit(&bio);
return ret;
}
enum {
DIO_SHOULD_DIRTY = 1,
DIO_IS_SYNC = 2,
};
struct blkdev_dio {
union {
struct kiocb *iocb;
struct task_struct *waiter;
};
size_t size;
atomic_t ref;
unsigned int flags;
struct bio bio ____cacheline_aligned_in_smp;
};
static struct bio_set blkdev_dio_pool;
static void blkdev_bio_end_io(struct bio *bio)
{
struct blkdev_dio *dio = bio->bi_private;
bool should_dirty = dio->flags & DIO_SHOULD_DIRTY;
if (bio->bi_status && !dio->bio.bi_status)
dio->bio.bi_status = bio->bi_status;
if (atomic_dec_and_test(&dio->ref)) {
if (!(dio->flags & DIO_IS_SYNC)) {
struct kiocb *iocb = dio->iocb;
ssize_t ret;
WRITE_ONCE(iocb->private, NULL);
if (likely(!dio->bio.bi_status)) {
ret = dio->size;
iocb->ki_pos += ret;
} else {
ret = blk_status_to_errno(dio->bio.bi_status);
}
dio->iocb->ki_complete(iocb, ret);
bio_put(&dio->bio);
} else {
struct task_struct *waiter = dio->waiter;
WRITE_ONCE(dio->waiter, NULL);
blk_wake_io_task(waiter);
}
}
if (should_dirty) {
bio_check_pages_dirty(bio);
} else {
bio_release_pages(bio, false);
bio_put(bio);
}
}
static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
struct block_device *bdev, unsigned int nr_pages)
{
struct blk_plug plug;
struct blkdev_dio *dio;
struct bio *bio;
bool is_read = (iov_iter_rw(iter) == READ), is_sync;
blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
loff_t pos = iocb->ki_pos;
int ret = 0;
if (iocb->ki_flags & IOCB_ALLOC_CACHE)
opf |= REQ_ALLOC_CACHE;
bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
&blkdev_dio_pool);
dio = container_of(bio, struct blkdev_dio, bio);
atomic_set(&dio->ref, 1);
/*
* Grab an extra reference to ensure the dio structure which is embedded
* into the first bio stays around.
*/
bio_get(bio);
is_sync = is_sync_kiocb(iocb);
if (is_sync) {
dio->flags = DIO_IS_SYNC;
dio->waiter = current;
} else {
dio->flags = 0;
dio->iocb = iocb;
}
dio->size = 0;
if (is_read && user_backed_iter(iter))
dio->flags |= DIO_SHOULD_DIRTY;
blk_start_plug(&plug);
for (;;) {
bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
bio->bi_private = dio;
bio->bi_end_io = blkdev_bio_end_io;
bio->bi_ioprio = iocb->ki_ioprio;
ret = bio_iov_iter_get_pages(bio, iter);
if (unlikely(ret)) {
bio->bi_status = BLK_STS_IOERR;
bio_endio(bio);
break;
}
if (iocb->ki_flags & IOCB_NOWAIT) {
/*
* This is nonblocking IO, and we need to allocate
* another bio if we have data left to map. As we
* cannot guarantee that one of the sub bios will not
* fail getting issued FOR NOWAIT and as error results
* are coalesced across all of them, be safe and ask for
* a retry of this from blocking context.
*/
if (unlikely(iov_iter_count(iter))) {
bio_release_pages(bio, false);
bio_clear_flag(bio, BIO_REFFED);
bio_put(bio);
blk_finish_plug(&plug);
return -EAGAIN;
}
bio->bi_opf |= REQ_NOWAIT;
}
if (is_read) {
if (dio->flags & DIO_SHOULD_DIRTY)
bio_set_pages_dirty(bio);
} else {
task_io_account_write(bio->bi_iter.bi_size);
}
dio->size += bio->bi_iter.bi_size;
pos += bio->bi_iter.bi_size;
nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);
if (!nr_pages) {
submit_bio(bio);
break;
}
atomic_inc(&dio->ref);
submit_bio(bio);
bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL);
}
blk_finish_plug(&plug);
if (!is_sync)
return -EIOCBQUEUED;
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
if (!READ_ONCE(dio->waiter))
break;
blk_io_schedule();
}
__set_current_state(TASK_RUNNING);
if (!ret)
ret = blk_status_to_errno(dio->bio.bi_status);
if (likely(!ret))
ret = dio->size;
bio_put(&dio->bio);
return ret;
}
static void blkdev_bio_end_io_async(struct bio *bio)
{
struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio);
struct kiocb *iocb = dio->iocb;
ssize_t ret;
WRITE_ONCE(iocb->private, NULL);
if (likely(!bio->bi_status)) {
ret = dio->size;
iocb->ki_pos += ret;
} else {
ret = blk_status_to_errno(bio->bi_status);
}
iocb->ki_complete(iocb, ret);
if (dio->flags & DIO_SHOULD_DIRTY) {
bio_check_pages_dirty(bio);
} else {
bio_release_pages(bio, false);
bio_put(bio);
}
}
static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
struct iov_iter *iter,
struct block_device *bdev,
unsigned int nr_pages)
{
bool is_read = iov_iter_rw(iter) == READ;
blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
struct blkdev_dio *dio;
struct bio *bio;
loff_t pos = iocb->ki_pos;
int ret = 0;
if (iocb->ki_flags & IOCB_ALLOC_CACHE)
opf |= REQ_ALLOC_CACHE;
bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
&blkdev_dio_pool);
dio = container_of(bio, struct blkdev_dio, bio);
dio->flags = 0;
dio->iocb = iocb;
bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
bio->bi_end_io = blkdev_bio_end_io_async;
bio->bi_ioprio = iocb->ki_ioprio;
if (iov_iter_is_bvec(iter)) {
/*
* Users don't rely on the iterator being in any particular
* state for async I/O returning -EIOCBQUEUED, hence we can
* avoid expensive iov_iter_advance(). Bypass
* bio_iov_iter_get_pages() and set the bvec directly.
*/
bio_iov_bvec_set(bio, iter);
} else {
ret = bio_iov_iter_get_pages(bio, iter);
if (unlikely(ret)) {
bio_put(bio);
return ret;
}
}
dio->size = bio->bi_iter.bi_size;
if (is_read) {
if (user_backed_iter(iter)) {
dio->flags |= DIO_SHOULD_DIRTY;
bio_set_pages_dirty(bio);
}
} else {
task_io_account_write(bio->bi_iter.bi_size);
}
if (iocb->ki_flags & IOCB_ATOMIC)
bio->bi_opf |= REQ_ATOMIC;
if (iocb->ki_flags & IOCB_NOWAIT)
bio->bi_opf |= REQ_NOWAIT;
if (iocb->ki_flags & IOCB_HIPRI) {
bio->bi_opf |= REQ_POLLED;
submit_bio(bio);
WRITE_ONCE(iocb->private, bio);
} else {
submit_bio(bio);
}
return -EIOCBQUEUED;
}
static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
{
struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
bool is_atomic = iocb->ki_flags & IOCB_ATOMIC;
unsigned int nr_pages;
if (!iov_iter_count(iter))
return 0;
if (blkdev_dio_invalid(bdev, iocb->ki_pos, iter, is_atomic))
return -EINVAL;
nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1);
if (likely(nr_pages <= BIO_MAX_VECS)) {
if (is_sync_kiocb(iocb))
return __blkdev_direct_IO_simple(iocb, iter, bdev,
nr_pages);
return __blkdev_direct_IO_async(iocb, iter, bdev, nr_pages);
} else if (is_atomic) {
return -EINVAL;
}
return __blkdev_direct_IO(iocb, iter, bdev, bio_max_segs(nr_pages));
}
static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
{
struct block_device *bdev = I_BDEV(inode);
loff_t isize = i_size_read(inode);
if (offset >= isize)
return -EIO;
iomap->bdev = bdev;
iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev));
iomap->type = IOMAP_MAPPED;
iomap->addr = iomap->offset;
iomap->length = isize - iomap->offset;
iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */
return 0;
}
static const struct iomap_ops blkdev_iomap_ops = {
.iomap_begin = blkdev_iomap_begin,
};
#ifdef CONFIG_BUFFER_HEAD
static int blkdev_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh, int create)
{
bh->b_bdev = I_BDEV(inode);
bh->b_blocknr = iblock;
set_buffer_mapped(bh);
return 0;
}
/*
* We cannot call mpage_writepages() as it does not take the buffer lock.
* We must use block_write_full_folio() directly which holds the buffer
* lock. The buffer lock provides the synchronisation with writeback
* that filesystems rely on when they use the blockdev's mapping.
*/
static int blkdev_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct blk_plug plug;
int err;
blk_start_plug(&plug);
err = write_cache_pages(mapping, wbc, block_write_full_folio,
blkdev_get_block);
blk_finish_plug(&plug);
return err;
}
static int blkdev_read_folio(struct file *file, struct folio *folio)
{
return block_read_full_folio(folio, blkdev_get_block);
}
static void blkdev_readahead(struct readahead_control *rac)
{
mpage_readahead(rac, blkdev_get_block);
}
static int blkdev_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, struct page **pagep, void **fsdata)
{
return block_write_begin(mapping, pos, len, pagep, blkdev_get_block);
}
static int blkdev_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied, struct page *page,
void *fsdata)
{
int ret;
ret = block_write_end(file, mapping, pos, len, copied, page, fsdata);
unlock_page(page);
put_page(page);
return ret;
}
const struct address_space_operations def_blk_aops = {
.dirty_folio = block_dirty_folio,
.invalidate_folio = block_invalidate_folio,
.read_folio = blkdev_read_folio,
.readahead = blkdev_readahead,
.writepages = blkdev_writepages,
.write_begin = blkdev_write_begin,
.write_end = blkdev_write_end,
.migrate_folio = buffer_migrate_folio_norefs,
.is_dirty_writeback = buffer_check_dirty_writeback,
};
#else /* CONFIG_BUFFER_HEAD */
static int blkdev_read_folio(struct file *file, struct folio *folio)
{
return iomap_read_folio(folio, &blkdev_iomap_ops);
}
static void blkdev_readahead(struct readahead_control *rac)
{
iomap_readahead(rac, &blkdev_iomap_ops);
}
static int blkdev_map_blocks(struct iomap_writepage_ctx *wpc,
struct inode *inode, loff_t offset, unsigned int len)
{
loff_t isize = i_size_read(inode);
if (WARN_ON_ONCE(offset >= isize))
return -EIO;
if (offset >= wpc->iomap.offset &&
offset < wpc->iomap.offset + wpc->iomap.length)
return 0;
return blkdev_iomap_begin(inode, offset, isize - offset,
IOMAP_WRITE, &wpc->iomap, NULL);
}
static const struct iomap_writeback_ops blkdev_writeback_ops = {
.map_blocks = blkdev_map_blocks,
};
static int blkdev_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct iomap_writepage_ctx wpc = { };
return iomap_writepages(mapping, wbc, &wpc, &blkdev_writeback_ops);
}
const struct address_space_operations def_blk_aops = {
.dirty_folio = filemap_dirty_folio,
.release_folio = iomap_release_folio,
.invalidate_folio = iomap_invalidate_folio,
.read_folio = blkdev_read_folio,
.readahead = blkdev_readahead,
.writepages = blkdev_writepages,
.is_partially_uptodate = iomap_is_partially_uptodate,
.error_remove_folio = generic_error_remove_folio,
.migrate_folio = filemap_migrate_folio,
};
#endif /* CONFIG_BUFFER_HEAD */
/*
* for a block special file file_inode(file)->i_size is zero
* so we compute the size by hand (just as in block_read/write above)
*/
static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence)
{
struct inode *bd_inode = bdev_file_inode(file);
loff_t retval;
inode_lock(bd_inode);
retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
inode_unlock(bd_inode);
return retval;
}
static int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
int datasync)
{
struct block_device *bdev = I_BDEV(filp->f_mapping->host);
int error;
error = file_write_and_wait_range(filp, start, end);
if (error)
return error;
/*
* There is no need to serialise calls to blkdev_issue_flush with
* i_mutex and doing so causes performance issues with concurrent
* O_SYNC writers to a block device.
*/
error = blkdev_issue_flush(bdev);
if (error == -EOPNOTSUPP)
error = 0;
return error;
}
/**
* file_to_blk_mode - get block open flags from file flags
* @file: file whose open flags should be converted
*
* Look at file open flags and generate corresponding block open flags from
* them. The function works both for file just being open (e.g. during ->open
* callback) and for file that is already open. This is actually non-trivial
* (see comment in the function).
*/
blk_mode_t file_to_blk_mode(struct file *file)
{
blk_mode_t mode = 0;
if (file->f_mode & FMODE_READ)
mode |= BLK_OPEN_READ;
if (file->f_mode & FMODE_WRITE)
mode |= BLK_OPEN_WRITE;
/*
* do_dentry_open() clears O_EXCL from f_flags, use file->private_data
* to determine whether the open was exclusive for already open files.
*/
if (file->private_data)
mode |= BLK_OPEN_EXCL;
else if (file->f_flags & O_EXCL)
mode |= BLK_OPEN_EXCL;
if (file->f_flags & O_NDELAY)
mode |= BLK_OPEN_NDELAY;
/*
* If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy
* driver has historically allowed ioctls as if the file was opened for
* writing, but does not allow and actual reads or writes.
*/
if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY))
mode |= BLK_OPEN_WRITE_IOCTL;
return mode;
}
static int blkdev_open(struct inode *inode, struct file *filp)
{
struct block_device *bdev;
blk_mode_t mode;
int ret;
mode = file_to_blk_mode(filp);
/* Use the file as the holder. */
if (mode & BLK_OPEN_EXCL)
filp->private_data = filp;
ret = bdev_permission(inode->i_rdev, mode, filp->private_data);
if (ret)
return ret;
bdev = blkdev_get_no_open(inode->i_rdev);
if (!bdev)
return -ENXIO;
if (bdev_can_atomic_write(bdev) && filp->f_flags & O_DIRECT)
filp->f_mode |= FMODE_CAN_ATOMIC_WRITE;
ret = bdev_open(bdev, mode, filp->private_data, NULL, filp);
if (ret)
blkdev_put_no_open(bdev);
return ret;
}
static int blkdev_release(struct inode *inode, struct file *filp)
{
bdev_release(filp);
return 0;
}
static ssize_t
blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from)
{
size_t count = iov_iter_count(from);
ssize_t written;
written = kiocb_invalidate_pages(iocb, count);
if (written) {
if (written == -EBUSY)
return 0;
return written;
}
written = blkdev_direct_IO(iocb, from);
if (written > 0) {
kiocb_invalidate_post_direct_write(iocb, count);
iocb->ki_pos += written;
count -= written;
}
if (written != -EIOCBQUEUED)
iov_iter_revert(from, count - iov_iter_count(from));
return written;
}
static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from)
{
return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops);
}
/*
* Write data to the block device. Only intended for the block device itself
* and the raw driver which basically is a fake block device.
*
* Does not take i_mutex for the write and thus is not for general purpose
* use.
*/
static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct inode *bd_inode = bdev_file_inode(file);
struct block_device *bdev = I_BDEV(bd_inode);
loff_t size = bdev_nr_bytes(bdev);
size_t shorted = 0;
ssize_t ret;
if (bdev_read_only(bdev))
return -EPERM;
if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev))
return -ETXTBSY;
if (!iov_iter_count(from))
return 0;
if (iocb->ki_pos >= size)
return -ENOSPC;
if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT)
return -EOPNOTSUPP;
size -= iocb->ki_pos;
if (iov_iter_count(from) > size) {
shorted = iov_iter_count(from) - size;
iov_iter_truncate(from, size);
}
ret = file_update_time(file);
if (ret)
return ret;
if (iocb->ki_flags & IOCB_DIRECT) {
ret = blkdev_direct_write(iocb, from);
if (ret >= 0 && iov_iter_count(from))
ret = direct_write_fallback(iocb, from, ret,
blkdev_buffered_write(iocb, from));
} else {
ret = blkdev_buffered_write(iocb, from);
}
if (ret > 0)
ret = generic_write_sync(iocb, ret);
iov_iter_reexpand(from, iov_iter_count(from) + shorted);
return ret;
}
static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
loff_t size = bdev_nr_bytes(bdev);
loff_t pos = iocb->ki_pos;
size_t shorted = 0;
ssize_t ret = 0;
size_t count;
if (unlikely(pos + iov_iter_count(to) > size)) {
if (pos >= size)
return 0;
size -= pos;
shorted = iov_iter_count(to) - size;
iov_iter_truncate(to, size);
}
count = iov_iter_count(to);
if (!count)
goto reexpand; /* skip atime */
if (iocb->ki_flags & IOCB_DIRECT) {
ret = kiocb_write_and_wait(iocb, count);
if (ret < 0)
goto reexpand;
file_accessed(iocb->ki_filp);
ret = blkdev_direct_IO(iocb, to);
if (ret >= 0) {
iocb->ki_pos += ret;
count -= ret;
}
iov_iter_revert(to, count - iov_iter_count(to));
if (ret < 0 || !count)
goto reexpand;
}
ret = filemap_read(iocb, to, ret);
reexpand:
if (unlikely(shorted))
iov_iter_reexpand(to, iov_iter_count(to) + shorted);
return ret;
}
#define BLKDEV_FALLOC_FL_SUPPORTED \
(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE)
static long blkdev_fallocate(struct file *file, int mode, loff_t start,
loff_t len)
{
struct inode *inode = bdev_file_inode(file);
struct block_device *bdev = I_BDEV(inode);
loff_t end = start + len - 1;
loff_t isize;
int error;
/* Fail if we don't recognize the flags. */
if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED)
return -EOPNOTSUPP;
/* Don't go off the end of the device. */
isize = bdev_nr_bytes(bdev);
if (start >= isize)
return -EINVAL;
if (end >= isize) {
if (mode & FALLOC_FL_KEEP_SIZE) {
len = isize - start;
end = start + len - 1;
} else
return -EINVAL;
}
/*
* Don't allow IO that isn't aligned to logical block size.
*/
if ((start | len) & (bdev_logical_block_size(bdev) - 1))
return -EINVAL;
filemap_invalidate_lock(inode->i_mapping);
/*
* Invalidate the page cache, including dirty pages, for valid
* de-allocate mode calls to fallocate().
*/
switch (mode) {
case FALLOC_FL_ZERO_RANGE:
case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
if (error)
goto fail;
error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
len >> SECTOR_SHIFT, GFP_KERNEL,
BLKDEV_ZERO_NOUNMAP);
break;
case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
if (error)
goto fail;
error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
len >> SECTOR_SHIFT, GFP_KERNEL,
BLKDEV_ZERO_NOFALLBACK);
break;
case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE:
error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
if (error)
goto fail;
error = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT,
len >> SECTOR_SHIFT, GFP_KERNEL);
break;
default:
error = -EOPNOTSUPP;
}
fail:
filemap_invalidate_unlock(inode->i_mapping);
return error;
}
static int blkdev_mmap(struct file *file, struct vm_area_struct *vma)
{
struct inode *bd_inode = bdev_file_inode(file);
if (bdev_read_only(I_BDEV(bd_inode)))
return generic_file_readonly_mmap(file, vma);
return generic_file_mmap(file, vma);
}
const struct file_operations def_blk_fops = {
.open = blkdev_open,
.release = blkdev_release,
.llseek = blkdev_llseek,
.read_iter = blkdev_read_iter,
.write_iter = blkdev_write_iter,
.iopoll = iocb_bio_iopoll,
.mmap = blkdev_mmap,
.fsync = blkdev_fsync,
.unlocked_ioctl = blkdev_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = compat_blkdev_ioctl,
#endif
.splice_read = filemap_splice_read,
.splice_write = iter_file_splice_write,
.fallocate = blkdev_fallocate,
.fop_flags = FOP_BUFFER_RASYNC,
};
static __init int blkdev_init(void)
{
return bioset_init(&blkdev_dio_pool, 4,
offsetof(struct blkdev_dio, bio),
BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE);
}
module_init(blkdev_init);