linux_dsm_epyc7002/fs/iomap.c
Eric Sandeen 79b3dbe4ad fs: fix iomap_bmap position calculation
The position calculation in iomap_bmap() shifts bno the wrong way,
so we don't progress properly and end up re-mapping block zero
over and over, yielding an unchanging physical block range as the
logical block advances:

# filefrag -Be file
 ext:   logical_offset:     physical_offset: length:   expected: flags:
   0:      0..       0:      21..        21:      1:             merged
   1:      1..       1:      21..        21:      1:         22: merged
Discontinuity: Block 1 is at 21 (was 22)
   2:      2..       2:      21..        21:      1:         22: merged
Discontinuity: Block 2 is at 21 (was 22)
   3:      3..       3:      21..        21:      1:         22: merged

This breaks the FIBMAP interface for anyone using it (XFS), which
in turn breaks LILO, zipl, etc.

Bug-actually-spotted-by: Darrick J. Wong <darrick.wong@oracle.com>
Fixes: 89eb1906a9 ("iomap: add an iomap-based bmap implementation")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-08-02 13:09:27 -07:00

1457 lines
36 KiB
C

/*
* Copyright (C) 2010 Red Hat, Inc.
* Copyright (c) 2016 Christoph Hellwig.
*
* 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/module.h>
#include <linux/compiler.h>
#include <linux/fs.h>
#include <linux/iomap.h>
#include <linux/uaccess.h>
#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/pagemap.h>
#include <linux/pagevec.h>
#include <linux/file.h>
#include <linux/uio.h>
#include <linux/backing-dev.h>
#include <linux/buffer_head.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/dax.h>
#include <linux/sched/signal.h>
#include <linux/swap.h>
#include "internal.h"
/*
* Execute a iomap write on a segment of the mapping that spans a
* contiguous range of pages that have identical block mapping state.
*
* This avoids the need to map pages individually, do individual allocations
* for each page and most importantly avoid the need for filesystem specific
* locking per page. Instead, all the operations are amortised over the entire
* range of pages. It is assumed that the filesystems will lock whatever
* resources they require in the iomap_begin call, and release them in the
* iomap_end call.
*/
loff_t
iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
const struct iomap_ops *ops, void *data, iomap_actor_t actor)
{
struct iomap iomap = { 0 };
loff_t written = 0, ret;
/*
* Need to map a range from start position for length bytes. This can
* span multiple pages - it is only guaranteed to return a range of a
* single type of pages (e.g. all into a hole, all mapped or all
* unwritten). Failure at this point has nothing to undo.
*
* If allocation is required for this range, reserve the space now so
* that the allocation is guaranteed to succeed later on. Once we copy
* the data into the page cache pages, then we cannot fail otherwise we
* expose transient stale data. If the reserve fails, we can safely
* back out at this point as there is nothing to undo.
*/
ret = ops->iomap_begin(inode, pos, length, flags, &iomap);
if (ret)
return ret;
if (WARN_ON(iomap.offset > pos))
return -EIO;
if (WARN_ON(iomap.length == 0))
return -EIO;
/*
* Cut down the length to the one actually provided by the filesystem,
* as it might not be able to give us the whole size that we requested.
*/
if (iomap.offset + iomap.length < pos + length)
length = iomap.offset + iomap.length - pos;
/*
* Now that we have guaranteed that the space allocation will succeed.
* we can do the copy-in page by page without having to worry about
* failures exposing transient data.
*/
written = actor(inode, pos, length, data, &iomap);
/*
* Now the data has been copied, commit the range we've copied. This
* should not fail unless the filesystem has had a fatal error.
*/
if (ops->iomap_end) {
ret = ops->iomap_end(inode, pos, length,
written > 0 ? written : 0,
flags, &iomap);
}
return written ? written : ret;
}
static sector_t
iomap_sector(struct iomap *iomap, loff_t pos)
{
return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
}
static void
iomap_write_failed(struct inode *inode, loff_t pos, unsigned len)
{
loff_t i_size = i_size_read(inode);
/*
* Only truncate newly allocated pages beyoned EOF, even if the
* write started inside the existing inode size.
*/
if (pos + len > i_size)
truncate_pagecache_range(inode, max(pos, i_size), pos + len);
}
static int
iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
struct page **pagep, struct iomap *iomap)
{
pgoff_t index = pos >> PAGE_SHIFT;
struct page *page;
int status = 0;
BUG_ON(pos + len > iomap->offset + iomap->length);
if (fatal_signal_pending(current))
return -EINTR;
page = grab_cache_page_write_begin(inode->i_mapping, index, flags);
if (!page)
return -ENOMEM;
status = __block_write_begin_int(page, pos, len, NULL, iomap);
if (unlikely(status)) {
unlock_page(page);
put_page(page);
page = NULL;
iomap_write_failed(inode, pos, len);
}
*pagep = page;
return status;
}
static int
iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
unsigned copied, struct page *page)
{
int ret;
ret = generic_write_end(NULL, inode->i_mapping, pos, len,
copied, page, NULL);
if (ret < len)
iomap_write_failed(inode, pos, len);
return ret;
}
static loff_t
iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
struct iomap *iomap)
{
struct iov_iter *i = data;
long status = 0;
ssize_t written = 0;
unsigned int flags = AOP_FLAG_NOFS;
do {
struct page *page;
unsigned long offset; /* Offset into pagecache page */
unsigned long bytes; /* Bytes to write to page */
size_t copied; /* Bytes copied from user */
offset = (pos & (PAGE_SIZE - 1));
bytes = min_t(unsigned long, PAGE_SIZE - offset,
iov_iter_count(i));
again:
if (bytes > length)
bytes = length;
/*
* Bring in the user page that we will copy from _first_.
* Otherwise there's a nasty deadlock on copying from the
* same page as we're writing to, without it being marked
* up-to-date.
*
* Not only is this an optimisation, but it is also required
* to check that the address is actually valid, when atomic
* usercopies are used, below.
*/
if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
status = -EFAULT;
break;
}
status = iomap_write_begin(inode, pos, bytes, flags, &page,
iomap);
if (unlikely(status))
break;
if (mapping_writably_mapped(inode->i_mapping))
flush_dcache_page(page);
copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes);
flush_dcache_page(page);
status = iomap_write_end(inode, pos, bytes, copied, page);
if (unlikely(status < 0))
break;
copied = status;
cond_resched();
iov_iter_advance(i, copied);
if (unlikely(copied == 0)) {
/*
* If we were unable to copy any data at all, we must
* fall back to a single segment length write.
*
* If we didn't fallback here, we could livelock
* because not all segments in the iov can be copied at
* once without a pagefault.
*/
bytes = min_t(unsigned long, PAGE_SIZE - offset,
iov_iter_single_seg_count(i));
goto again;
}
pos += copied;
written += copied;
length -= copied;
balance_dirty_pages_ratelimited(inode->i_mapping);
} while (iov_iter_count(i) && length);
return written ? written : status;
}
ssize_t
iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter,
const struct iomap_ops *ops)
{
struct inode *inode = iocb->ki_filp->f_mapping->host;
loff_t pos = iocb->ki_pos, ret = 0, written = 0;
while (iov_iter_count(iter)) {
ret = iomap_apply(inode, pos, iov_iter_count(iter),
IOMAP_WRITE, ops, iter, iomap_write_actor);
if (ret <= 0)
break;
pos += ret;
written += ret;
}
return written ? written : ret;
}
EXPORT_SYMBOL_GPL(iomap_file_buffered_write);
static struct page *
__iomap_read_page(struct inode *inode, loff_t offset)
{
struct address_space *mapping = inode->i_mapping;
struct page *page;
page = read_mapping_page(mapping, offset >> PAGE_SHIFT, NULL);
if (IS_ERR(page))
return page;
if (!PageUptodate(page)) {
put_page(page);
return ERR_PTR(-EIO);
}
return page;
}
static loff_t
iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
struct iomap *iomap)
{
long status = 0;
ssize_t written = 0;
do {
struct page *page, *rpage;
unsigned long offset; /* Offset into pagecache page */
unsigned long bytes; /* Bytes to write to page */
offset = (pos & (PAGE_SIZE - 1));
bytes = min_t(loff_t, PAGE_SIZE - offset, length);
rpage = __iomap_read_page(inode, pos);
if (IS_ERR(rpage))
return PTR_ERR(rpage);
status = iomap_write_begin(inode, pos, bytes,
AOP_FLAG_NOFS, &page, iomap);
put_page(rpage);
if (unlikely(status))
return status;
WARN_ON_ONCE(!PageUptodate(page));
status = iomap_write_end(inode, pos, bytes, bytes, page);
if (unlikely(status <= 0)) {
if (WARN_ON_ONCE(status == 0))
return -EIO;
return status;
}
cond_resched();
pos += status;
written += status;
length -= status;
balance_dirty_pages_ratelimited(inode->i_mapping);
} while (length);
return written;
}
int
iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
const struct iomap_ops *ops)
{
loff_t ret;
while (len) {
ret = iomap_apply(inode, pos, len, IOMAP_WRITE, ops, NULL,
iomap_dirty_actor);
if (ret <= 0)
return ret;
pos += ret;
len -= ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(iomap_file_dirty);
static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset,
unsigned bytes, struct iomap *iomap)
{
struct page *page;
int status;
status = iomap_write_begin(inode, pos, bytes, AOP_FLAG_NOFS, &page,
iomap);
if (status)
return status;
zero_user(page, offset, bytes);
mark_page_accessed(page);
return iomap_write_end(inode, pos, bytes, bytes, page);
}
static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes,
struct iomap *iomap)
{
return __dax_zero_page_range(iomap->bdev, iomap->dax_dev,
iomap_sector(iomap, pos & PAGE_MASK), offset, bytes);
}
static loff_t
iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count,
void *data, struct iomap *iomap)
{
bool *did_zero = data;
loff_t written = 0;
int status;
/* already zeroed? we're done. */
if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN)
return count;
do {
unsigned offset, bytes;
offset = pos & (PAGE_SIZE - 1); /* Within page */
bytes = min_t(loff_t, PAGE_SIZE - offset, count);
if (IS_DAX(inode))
status = iomap_dax_zero(pos, offset, bytes, iomap);
else
status = iomap_zero(inode, pos, offset, bytes, iomap);
if (status < 0)
return status;
pos += bytes;
count -= bytes;
written += bytes;
if (did_zero)
*did_zero = true;
} while (count > 0);
return written;
}
int
iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
const struct iomap_ops *ops)
{
loff_t ret;
while (len > 0) {
ret = iomap_apply(inode, pos, len, IOMAP_ZERO,
ops, did_zero, iomap_zero_range_actor);
if (ret <= 0)
return ret;
pos += ret;
len -= ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(iomap_zero_range);
int
iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
const struct iomap_ops *ops)
{
unsigned int blocksize = i_blocksize(inode);
unsigned int off = pos & (blocksize - 1);
/* Block boundary? Nothing to do */
if (!off)
return 0;
return iomap_zero_range(inode, pos, blocksize - off, did_zero, ops);
}
EXPORT_SYMBOL_GPL(iomap_truncate_page);
static loff_t
iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length,
void *data, struct iomap *iomap)
{
struct page *page = data;
int ret;
ret = __block_write_begin_int(page, pos, length, NULL, iomap);
if (ret)
return ret;
block_commit_write(page, 0, length);
return length;
}
int iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops)
{
struct page *page = vmf->page;
struct inode *inode = file_inode(vmf->vma->vm_file);
unsigned long length;
loff_t offset, size;
ssize_t ret;
lock_page(page);
size = i_size_read(inode);
if ((page->mapping != inode->i_mapping) ||
(page_offset(page) > size)) {
/* We overload EFAULT to mean page got truncated */
ret = -EFAULT;
goto out_unlock;
}
/* page is wholly or partially inside EOF */
if (((page->index + 1) << PAGE_SHIFT) > size)
length = size & ~PAGE_MASK;
else
length = PAGE_SIZE;
offset = page_offset(page);
while (length > 0) {
ret = iomap_apply(inode, offset, length,
IOMAP_WRITE | IOMAP_FAULT, ops, page,
iomap_page_mkwrite_actor);
if (unlikely(ret <= 0))
goto out_unlock;
offset += ret;
length -= ret;
}
set_page_dirty(page);
wait_for_stable_page(page);
return VM_FAULT_LOCKED;
out_unlock:
unlock_page(page);
return block_page_mkwrite_return(ret);
}
EXPORT_SYMBOL_GPL(iomap_page_mkwrite);
struct fiemap_ctx {
struct fiemap_extent_info *fi;
struct iomap prev;
};
static int iomap_to_fiemap(struct fiemap_extent_info *fi,
struct iomap *iomap, u32 flags)
{
switch (iomap->type) {
case IOMAP_HOLE:
/* skip holes */
return 0;
case IOMAP_DELALLOC:
flags |= FIEMAP_EXTENT_DELALLOC | FIEMAP_EXTENT_UNKNOWN;
break;
case IOMAP_MAPPED:
break;
case IOMAP_UNWRITTEN:
flags |= FIEMAP_EXTENT_UNWRITTEN;
break;
case IOMAP_INLINE:
flags |= FIEMAP_EXTENT_DATA_INLINE;
break;
}
if (iomap->flags & IOMAP_F_MERGED)
flags |= FIEMAP_EXTENT_MERGED;
if (iomap->flags & IOMAP_F_SHARED)
flags |= FIEMAP_EXTENT_SHARED;
return fiemap_fill_next_extent(fi, iomap->offset,
iomap->addr != IOMAP_NULL_ADDR ? iomap->addr : 0,
iomap->length, flags);
}
static loff_t
iomap_fiemap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
struct iomap *iomap)
{
struct fiemap_ctx *ctx = data;
loff_t ret = length;
if (iomap->type == IOMAP_HOLE)
return length;
ret = iomap_to_fiemap(ctx->fi, &ctx->prev, 0);
ctx->prev = *iomap;
switch (ret) {
case 0: /* success */
return length;
case 1: /* extent array full */
return 0;
default:
return ret;
}
}
int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi,
loff_t start, loff_t len, const struct iomap_ops *ops)
{
struct fiemap_ctx ctx;
loff_t ret;
memset(&ctx, 0, sizeof(ctx));
ctx.fi = fi;
ctx.prev.type = IOMAP_HOLE;
ret = fiemap_check_flags(fi, FIEMAP_FLAG_SYNC);
if (ret)
return ret;
if (fi->fi_flags & FIEMAP_FLAG_SYNC) {
ret = filemap_write_and_wait(inode->i_mapping);
if (ret)
return ret;
}
while (len > 0) {
ret = iomap_apply(inode, start, len, IOMAP_REPORT, ops, &ctx,
iomap_fiemap_actor);
/* inode with no (attribute) mapping will give ENOENT */
if (ret == -ENOENT)
break;
if (ret < 0)
return ret;
if (ret == 0)
break;
start += ret;
len -= ret;
}
if (ctx.prev.type != IOMAP_HOLE) {
ret = iomap_to_fiemap(fi, &ctx.prev, FIEMAP_EXTENT_LAST);
if (ret < 0)
return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(iomap_fiemap);
/*
* Seek for SEEK_DATA / SEEK_HOLE within @page, starting at @lastoff.
* Returns true if found and updates @lastoff to the offset in file.
*/
static bool
page_seek_hole_data(struct inode *inode, struct page *page, loff_t *lastoff,
int whence)
{
const struct address_space_operations *ops = inode->i_mapping->a_ops;
unsigned int bsize = i_blocksize(inode), off;
bool seek_data = whence == SEEK_DATA;
loff_t poff = page_offset(page);
if (WARN_ON_ONCE(*lastoff >= poff + PAGE_SIZE))
return false;
if (*lastoff < poff) {
/*
* Last offset smaller than the start of the page means we found
* a hole:
*/
if (whence == SEEK_HOLE)
return true;
*lastoff = poff;
}
/*
* Just check the page unless we can and should check block ranges:
*/
if (bsize == PAGE_SIZE || !ops->is_partially_uptodate)
return PageUptodate(page) == seek_data;
lock_page(page);
if (unlikely(page->mapping != inode->i_mapping))
goto out_unlock_not_found;
for (off = 0; off < PAGE_SIZE; off += bsize) {
if ((*lastoff & ~PAGE_MASK) >= off + bsize)
continue;
if (ops->is_partially_uptodate(page, off, bsize) == seek_data) {
unlock_page(page);
return true;
}
*lastoff = poff + off + bsize;
}
out_unlock_not_found:
unlock_page(page);
return false;
}
/*
* Seek for SEEK_DATA / SEEK_HOLE in the page cache.
*
* Within unwritten extents, the page cache determines which parts are holes
* and which are data: uptodate buffer heads count as data; everything else
* counts as a hole.
*
* Returns the resulting offset on successs, and -ENOENT otherwise.
*/
static loff_t
page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length,
int whence)
{
pgoff_t index = offset >> PAGE_SHIFT;
pgoff_t end = DIV_ROUND_UP(offset + length, PAGE_SIZE);
loff_t lastoff = offset;
struct pagevec pvec;
if (length <= 0)
return -ENOENT;
pagevec_init(&pvec);
do {
unsigned nr_pages, i;
nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping, &index,
end - 1);
if (nr_pages == 0)
break;
for (i = 0; i < nr_pages; i++) {
struct page *page = pvec.pages[i];
if (page_seek_hole_data(inode, page, &lastoff, whence))
goto check_range;
lastoff = page_offset(page) + PAGE_SIZE;
}
pagevec_release(&pvec);
} while (index < end);
/* When no page at lastoff and we are not done, we found a hole. */
if (whence != SEEK_HOLE)
goto not_found;
check_range:
if (lastoff < offset + length)
goto out;
not_found:
lastoff = -ENOENT;
out:
pagevec_release(&pvec);
return lastoff;
}
static loff_t
iomap_seek_hole_actor(struct inode *inode, loff_t offset, loff_t length,
void *data, struct iomap *iomap)
{
switch (iomap->type) {
case IOMAP_UNWRITTEN:
offset = page_cache_seek_hole_data(inode, offset, length,
SEEK_HOLE);
if (offset < 0)
return length;
/* fall through */
case IOMAP_HOLE:
*(loff_t *)data = offset;
return 0;
default:
return length;
}
}
loff_t
iomap_seek_hole(struct inode *inode, loff_t offset, const struct iomap_ops *ops)
{
loff_t size = i_size_read(inode);
loff_t length = size - offset;
loff_t ret;
/* Nothing to be found before or beyond the end of the file. */
if (offset < 0 || offset >= size)
return -ENXIO;
while (length > 0) {
ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops,
&offset, iomap_seek_hole_actor);
if (ret < 0)
return ret;
if (ret == 0)
break;
offset += ret;
length -= ret;
}
return offset;
}
EXPORT_SYMBOL_GPL(iomap_seek_hole);
static loff_t
iomap_seek_data_actor(struct inode *inode, loff_t offset, loff_t length,
void *data, struct iomap *iomap)
{
switch (iomap->type) {
case IOMAP_HOLE:
return length;
case IOMAP_UNWRITTEN:
offset = page_cache_seek_hole_data(inode, offset, length,
SEEK_DATA);
if (offset < 0)
return length;
/*FALLTHRU*/
default:
*(loff_t *)data = offset;
return 0;
}
}
loff_t
iomap_seek_data(struct inode *inode, loff_t offset, const struct iomap_ops *ops)
{
loff_t size = i_size_read(inode);
loff_t length = size - offset;
loff_t ret;
/* Nothing to be found before or beyond the end of the file. */
if (offset < 0 || offset >= size)
return -ENXIO;
while (length > 0) {
ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops,
&offset, iomap_seek_data_actor);
if (ret < 0)
return ret;
if (ret == 0)
break;
offset += ret;
length -= ret;
}
if (length <= 0)
return -ENXIO;
return offset;
}
EXPORT_SYMBOL_GPL(iomap_seek_data);
/*
* Private flags for iomap_dio, must not overlap with the public ones in
* iomap.h:
*/
#define IOMAP_DIO_WRITE_FUA (1 << 28)
#define IOMAP_DIO_NEED_SYNC (1 << 29)
#define IOMAP_DIO_WRITE (1 << 30)
#define IOMAP_DIO_DIRTY (1 << 31)
struct iomap_dio {
struct kiocb *iocb;
iomap_dio_end_io_t *end_io;
loff_t i_size;
loff_t size;
atomic_t ref;
unsigned flags;
int error;
union {
/* used during submission and for synchronous completion: */
struct {
struct iov_iter *iter;
struct task_struct *waiter;
struct request_queue *last_queue;
blk_qc_t cookie;
} submit;
/* used for aio completion: */
struct {
struct work_struct work;
} aio;
};
};
static ssize_t iomap_dio_complete(struct iomap_dio *dio)
{
struct kiocb *iocb = dio->iocb;
struct inode *inode = file_inode(iocb->ki_filp);
loff_t offset = iocb->ki_pos;
ssize_t ret;
if (dio->end_io) {
ret = dio->end_io(iocb,
dio->error ? dio->error : dio->size,
dio->flags);
} else {
ret = dio->error;
}
if (likely(!ret)) {
ret = dio->size;
/* check for short read */
if (offset + ret > dio->i_size &&
!(dio->flags & IOMAP_DIO_WRITE))
ret = dio->i_size - offset;
iocb->ki_pos += ret;
}
/*
* Try again to invalidate clean pages which might have been cached by
* non-direct readahead, or faulted in by get_user_pages() if the source
* of the write was an mmap'ed region of the file we're writing. Either
* one is a pretty crazy thing to do, so we don't support it 100%. If
* this invalidation fails, tough, the write still worked...
*
* And this page cache invalidation has to be after dio->end_io(), as
* some filesystems convert unwritten extents to real allocations in
* end_io() when necessary, otherwise a racing buffer read would cache
* zeros from unwritten extents.
*/
if (!dio->error &&
(dio->flags & IOMAP_DIO_WRITE) && inode->i_mapping->nrpages) {
int err;
err = invalidate_inode_pages2_range(inode->i_mapping,
offset >> PAGE_SHIFT,
(offset + dio->size - 1) >> PAGE_SHIFT);
if (err)
dio_warn_stale_pagecache(iocb->ki_filp);
}
/*
* If this is a DSYNC write, make sure we push it to stable storage now
* that we've written data.
*/
if (ret > 0 && (dio->flags & IOMAP_DIO_NEED_SYNC))
ret = generic_write_sync(iocb, ret);
inode_dio_end(file_inode(iocb->ki_filp));
kfree(dio);
return ret;
}
static void iomap_dio_complete_work(struct work_struct *work)
{
struct iomap_dio *dio = container_of(work, struct iomap_dio, aio.work);
struct kiocb *iocb = dio->iocb;
iocb->ki_complete(iocb, iomap_dio_complete(dio), 0);
}
/*
* Set an error in the dio if none is set yet. We have to use cmpxchg
* as the submission context and the completion context(s) can race to
* update the error.
*/
static inline void iomap_dio_set_error(struct iomap_dio *dio, int ret)
{
cmpxchg(&dio->error, 0, ret);
}
static void iomap_dio_bio_end_io(struct bio *bio)
{
struct iomap_dio *dio = bio->bi_private;
bool should_dirty = (dio->flags & IOMAP_DIO_DIRTY);
if (bio->bi_status)
iomap_dio_set_error(dio, blk_status_to_errno(bio->bi_status));
if (atomic_dec_and_test(&dio->ref)) {
if (is_sync_kiocb(dio->iocb)) {
struct task_struct *waiter = dio->submit.waiter;
WRITE_ONCE(dio->submit.waiter, NULL);
wake_up_process(waiter);
} else if (dio->flags & IOMAP_DIO_WRITE) {
struct inode *inode = file_inode(dio->iocb->ki_filp);
INIT_WORK(&dio->aio.work, iomap_dio_complete_work);
queue_work(inode->i_sb->s_dio_done_wq, &dio->aio.work);
} else {
iomap_dio_complete_work(&dio->aio.work);
}
}
if (should_dirty) {
bio_check_pages_dirty(bio);
} else {
struct bio_vec *bvec;
int i;
bio_for_each_segment_all(bvec, bio, i)
put_page(bvec->bv_page);
bio_put(bio);
}
}
static blk_qc_t
iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
unsigned len)
{
struct page *page = ZERO_PAGE(0);
struct bio *bio;
bio = bio_alloc(GFP_KERNEL, 1);
bio_set_dev(bio, iomap->bdev);
bio->bi_iter.bi_sector = iomap_sector(iomap, pos);
bio->bi_private = dio;
bio->bi_end_io = iomap_dio_bio_end_io;
get_page(page);
__bio_add_page(bio, page, len, 0);
bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC | REQ_IDLE);
atomic_inc(&dio->ref);
return submit_bio(bio);
}
static loff_t
iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length,
void *data, struct iomap *iomap)
{
struct iomap_dio *dio = data;
unsigned int blkbits = blksize_bits(bdev_logical_block_size(iomap->bdev));
unsigned int fs_block_size = i_blocksize(inode), pad;
unsigned int align = iov_iter_alignment(dio->submit.iter);
struct iov_iter iter;
struct bio *bio;
bool need_zeroout = false;
bool use_fua = false;
int nr_pages, ret;
size_t copied = 0;
if ((pos | length | align) & ((1 << blkbits) - 1))
return -EINVAL;
switch (iomap->type) {
case IOMAP_HOLE:
if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE))
return -EIO;
/*FALLTHRU*/
case IOMAP_UNWRITTEN:
if (!(dio->flags & IOMAP_DIO_WRITE)) {
length = iov_iter_zero(length, dio->submit.iter);
dio->size += length;
return length;
}
dio->flags |= IOMAP_DIO_UNWRITTEN;
need_zeroout = true;
break;
case IOMAP_MAPPED:
if (iomap->flags & IOMAP_F_SHARED)
dio->flags |= IOMAP_DIO_COW;
if (iomap->flags & IOMAP_F_NEW) {
need_zeroout = true;
} else {
/*
* Use a FUA write if we need datasync semantics, this
* is a pure data IO that doesn't require any metadata
* updates and the underlying device supports FUA. This
* allows us to avoid cache flushes on IO completion.
*/
if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) &&
(dio->flags & IOMAP_DIO_WRITE_FUA) &&
blk_queue_fua(bdev_get_queue(iomap->bdev)))
use_fua = true;
}
break;
default:
WARN_ON_ONCE(1);
return -EIO;
}
/*
* Operate on a partial iter trimmed to the extent we were called for.
* We'll update the iter in the dio once we're done with this extent.
*/
iter = *dio->submit.iter;
iov_iter_truncate(&iter, length);
nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES);
if (nr_pages <= 0)
return nr_pages;
if (need_zeroout) {
/* zero out from the start of the block to the write offset */
pad = pos & (fs_block_size - 1);
if (pad)
iomap_dio_zero(dio, iomap, pos - pad, pad);
}
do {
size_t n;
if (dio->error) {
iov_iter_revert(dio->submit.iter, copied);
return 0;
}
bio = bio_alloc(GFP_KERNEL, nr_pages);
bio_set_dev(bio, iomap->bdev);
bio->bi_iter.bi_sector = iomap_sector(iomap, pos);
bio->bi_write_hint = dio->iocb->ki_hint;
bio->bi_ioprio = dio->iocb->ki_ioprio;
bio->bi_private = dio;
bio->bi_end_io = iomap_dio_bio_end_io;
ret = bio_iov_iter_get_pages(bio, &iter);
if (unlikely(ret)) {
bio_put(bio);
return copied ? copied : ret;
}
n = bio->bi_iter.bi_size;
if (dio->flags & IOMAP_DIO_WRITE) {
bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
if (use_fua)
bio->bi_opf |= REQ_FUA;
else
dio->flags &= ~IOMAP_DIO_WRITE_FUA;
task_io_account_write(n);
} else {
bio->bi_opf = REQ_OP_READ;
if (dio->flags & IOMAP_DIO_DIRTY)
bio_set_pages_dirty(bio);
}
iov_iter_advance(dio->submit.iter, n);
dio->size += n;
pos += n;
copied += n;
nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES);
atomic_inc(&dio->ref);
dio->submit.last_queue = bdev_get_queue(iomap->bdev);
dio->submit.cookie = submit_bio(bio);
} while (nr_pages);
if (need_zeroout) {
/* zero out from the end of the write to the end of the block */
pad = pos & (fs_block_size - 1);
if (pad)
iomap_dio_zero(dio, iomap, pos, fs_block_size - pad);
}
return copied;
}
/*
* iomap_dio_rw() always completes O_[D]SYNC writes regardless of whether the IO
* is being issued as AIO or not. This allows us to optimise pure data writes
* to use REQ_FUA rather than requiring generic_write_sync() to issue a
* REQ_FLUSH post write. This is slightly tricky because a single request here
* can be mapped into multiple disjoint IOs and only a subset of the IOs issued
* may be pure data writes. In that case, we still need to do a full data sync
* completion.
*/
ssize_t
iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
const struct iomap_ops *ops, iomap_dio_end_io_t end_io)
{
struct address_space *mapping = iocb->ki_filp->f_mapping;
struct inode *inode = file_inode(iocb->ki_filp);
size_t count = iov_iter_count(iter);
loff_t pos = iocb->ki_pos, start = pos;
loff_t end = iocb->ki_pos + count - 1, ret = 0;
unsigned int flags = IOMAP_DIRECT;
struct blk_plug plug;
struct iomap_dio *dio;
lockdep_assert_held(&inode->i_rwsem);
if (!count)
return 0;
dio = kmalloc(sizeof(*dio), GFP_KERNEL);
if (!dio)
return -ENOMEM;
dio->iocb = iocb;
atomic_set(&dio->ref, 1);
dio->size = 0;
dio->i_size = i_size_read(inode);
dio->end_io = end_io;
dio->error = 0;
dio->flags = 0;
dio->submit.iter = iter;
if (is_sync_kiocb(iocb)) {
dio->submit.waiter = current;
dio->submit.cookie = BLK_QC_T_NONE;
dio->submit.last_queue = NULL;
}
if (iov_iter_rw(iter) == READ) {
if (pos >= dio->i_size)
goto out_free_dio;
if (iter->type == ITER_IOVEC)
dio->flags |= IOMAP_DIO_DIRTY;
} else {
flags |= IOMAP_WRITE;
dio->flags |= IOMAP_DIO_WRITE;
/* for data sync or sync, we need sync completion processing */
if (iocb->ki_flags & IOCB_DSYNC)
dio->flags |= IOMAP_DIO_NEED_SYNC;
/*
* For datasync only writes, we optimistically try using FUA for
* this IO. Any non-FUA write that occurs will clear this flag,
* hence we know before completion whether a cache flush is
* necessary.
*/
if ((iocb->ki_flags & (IOCB_DSYNC | IOCB_SYNC)) == IOCB_DSYNC)
dio->flags |= IOMAP_DIO_WRITE_FUA;
}
if (iocb->ki_flags & IOCB_NOWAIT) {
if (filemap_range_has_page(mapping, start, end)) {
ret = -EAGAIN;
goto out_free_dio;
}
flags |= IOMAP_NOWAIT;
}
ret = filemap_write_and_wait_range(mapping, start, end);
if (ret)
goto out_free_dio;
/*
* Try to invalidate cache pages for the range we're direct
* writing. If this invalidation fails, tough, the write will
* still work, but racing two incompatible write paths is a
* pretty crazy thing to do, so we don't support it 100%.
*/
ret = invalidate_inode_pages2_range(mapping,
start >> PAGE_SHIFT, end >> PAGE_SHIFT);
if (ret)
dio_warn_stale_pagecache(iocb->ki_filp);
ret = 0;
if (iov_iter_rw(iter) == WRITE && !is_sync_kiocb(iocb) &&
!inode->i_sb->s_dio_done_wq) {
ret = sb_init_dio_done_wq(inode->i_sb);
if (ret < 0)
goto out_free_dio;
}
inode_dio_begin(inode);
blk_start_plug(&plug);
do {
ret = iomap_apply(inode, pos, count, flags, ops, dio,
iomap_dio_actor);
if (ret <= 0) {
/* magic error code to fall back to buffered I/O */
if (ret == -ENOTBLK)
ret = 0;
break;
}
pos += ret;
if (iov_iter_rw(iter) == READ && pos >= dio->i_size)
break;
} while ((count = iov_iter_count(iter)) > 0);
blk_finish_plug(&plug);
if (ret < 0)
iomap_dio_set_error(dio, ret);
/*
* If all the writes we issued were FUA, we don't need to flush the
* cache on IO completion. Clear the sync flag for this case.
*/
if (dio->flags & IOMAP_DIO_WRITE_FUA)
dio->flags &= ~IOMAP_DIO_NEED_SYNC;
if (!atomic_dec_and_test(&dio->ref)) {
if (!is_sync_kiocb(iocb))
return -EIOCBQUEUED;
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
if (!READ_ONCE(dio->submit.waiter))
break;
if (!(iocb->ki_flags & IOCB_HIPRI) ||
!dio->submit.last_queue ||
!blk_poll(dio->submit.last_queue,
dio->submit.cookie))
io_schedule();
}
__set_current_state(TASK_RUNNING);
}
ret = iomap_dio_complete(dio);
return ret;
out_free_dio:
kfree(dio);
return ret;
}
EXPORT_SYMBOL_GPL(iomap_dio_rw);
/* Swapfile activation */
#ifdef CONFIG_SWAP
struct iomap_swapfile_info {
struct iomap iomap; /* accumulated iomap */
struct swap_info_struct *sis;
uint64_t lowest_ppage; /* lowest physical addr seen (pages) */
uint64_t highest_ppage; /* highest physical addr seen (pages) */
unsigned long nr_pages; /* number of pages collected */
int nr_extents; /* extent count */
};
/*
* Collect physical extents for this swap file. Physical extents reported to
* the swap code must be trimmed to align to a page boundary. The logical
* offset within the file is irrelevant since the swapfile code maps logical
* page numbers of the swap device to the physical page-aligned extents.
*/
static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi)
{
struct iomap *iomap = &isi->iomap;
unsigned long nr_pages;
uint64_t first_ppage;
uint64_t first_ppage_reported;
uint64_t next_ppage;
int error;
/*
* Round the start up and the end down so that the physical
* extent aligns to a page boundary.
*/
first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT;
next_ppage = ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >>
PAGE_SHIFT;
/* Skip too-short physical extents. */
if (first_ppage >= next_ppage)
return 0;
nr_pages = next_ppage - first_ppage;
/*
* Calculate how much swap space we're adding; the first page contains
* the swap header and doesn't count. The mm still wants that first
* page fed to add_swap_extent, however.
*/
first_ppage_reported = first_ppage;
if (iomap->offset == 0)
first_ppage_reported++;
if (isi->lowest_ppage > first_ppage_reported)
isi->lowest_ppage = first_ppage_reported;
if (isi->highest_ppage < (next_ppage - 1))
isi->highest_ppage = next_ppage - 1;
/* Add extent, set up for the next call. */
error = add_swap_extent(isi->sis, isi->nr_pages, nr_pages, first_ppage);
if (error < 0)
return error;
isi->nr_extents += error;
isi->nr_pages += nr_pages;
return 0;
}
/*
* Accumulate iomaps for this swap file. We have to accumulate iomaps because
* swap only cares about contiguous page-aligned physical extents and makes no
* distinction between written and unwritten extents.
*/
static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
loff_t count, void *data, struct iomap *iomap)
{
struct iomap_swapfile_info *isi = data;
int error;
switch (iomap->type) {
case IOMAP_MAPPED:
case IOMAP_UNWRITTEN:
/* Only real or unwritten extents. */
break;
case IOMAP_INLINE:
/* No inline data. */
pr_err("swapon: file is inline\n");
return -EINVAL;
default:
pr_err("swapon: file has unallocated extents\n");
return -EINVAL;
}
/* No uncommitted metadata or shared blocks. */
if (iomap->flags & IOMAP_F_DIRTY) {
pr_err("swapon: file is not committed\n");
return -EINVAL;
}
if (iomap->flags & IOMAP_F_SHARED) {
pr_err("swapon: file has shared extents\n");
return -EINVAL;
}
/* Only one bdev per swap file. */
if (iomap->bdev != isi->sis->bdev) {
pr_err("swapon: file is on multiple devices\n");
return -EINVAL;
}
if (isi->iomap.length == 0) {
/* No accumulated extent, so just store it. */
memcpy(&isi->iomap, iomap, sizeof(isi->iomap));
} else if (isi->iomap.addr + isi->iomap.length == iomap->addr) {
/* Append this to the accumulated extent. */
isi->iomap.length += iomap->length;
} else {
/* Otherwise, add the retained iomap and store this one. */
error = iomap_swapfile_add_extent(isi);
if (error)
return error;
memcpy(&isi->iomap, iomap, sizeof(isi->iomap));
}
return count;
}
/*
* Iterate a swap file's iomaps to construct physical extents that can be
* passed to the swapfile subsystem.
*/
int iomap_swapfile_activate(struct swap_info_struct *sis,
struct file *swap_file, sector_t *pagespan,
const struct iomap_ops *ops)
{
struct iomap_swapfile_info isi = {
.sis = sis,
.lowest_ppage = (sector_t)-1ULL,
};
struct address_space *mapping = swap_file->f_mapping;
struct inode *inode = mapping->host;
loff_t pos = 0;
loff_t len = ALIGN_DOWN(i_size_read(inode), PAGE_SIZE);
loff_t ret;
/*
* Persist all file mapping metadata so that we won't have any
* IOMAP_F_DIRTY iomaps.
*/
ret = vfs_fsync(swap_file, 1);
if (ret)
return ret;
while (len > 0) {
ret = iomap_apply(inode, pos, len, IOMAP_REPORT,
ops, &isi, iomap_swapfile_activate_actor);
if (ret <= 0)
return ret;
pos += ret;
len -= ret;
}
if (isi.iomap.length) {
ret = iomap_swapfile_add_extent(&isi);
if (ret)
return ret;
}
*pagespan = 1 + isi.highest_ppage - isi.lowest_ppage;
sis->max = isi.nr_pages;
sis->pages = isi.nr_pages - 1;
sis->highest_bit = isi.nr_pages - 1;
return isi.nr_extents;
}
EXPORT_SYMBOL_GPL(iomap_swapfile_activate);
#endif /* CONFIG_SWAP */
static loff_t
iomap_bmap_actor(struct inode *inode, loff_t pos, loff_t length,
void *data, struct iomap *iomap)
{
sector_t *bno = data, addr;
if (iomap->type == IOMAP_MAPPED) {
addr = (pos - iomap->offset + iomap->addr) >> inode->i_blkbits;
if (addr > INT_MAX)
WARN(1, "would truncate bmap result\n");
else
*bno = addr;
}
return 0;
}
/* legacy ->bmap interface. 0 is the error return (!) */
sector_t
iomap_bmap(struct address_space *mapping, sector_t bno,
const struct iomap_ops *ops)
{
struct inode *inode = mapping->host;
loff_t pos = bno << inode->i_blkbits;
unsigned blocksize = i_blocksize(inode);
if (filemap_write_and_wait(mapping))
return 0;
bno = 0;
iomap_apply(inode, pos, blocksize, 0, ops, &bno, iomap_bmap_actor);
return bno;
}
EXPORT_SYMBOL_GPL(iomap_bmap);