* [PATCH 5/9] iomap: move the direct IO code into a separate file
2019-07-15 17:59 [PATCH v2 0/9] iomap: regroup code by functional area Darrick J. Wong
` (3 preceding siblings ...)
2019-07-15 17:59 ` [PATCH 4/9] iomap: move the SEEK_HOLE " Darrick J. Wong
@ 2019-07-15 17:59 ` Darrick J. Wong
2019-07-17 5:02 ` Christoph Hellwig
2019-07-15 17:59 ` [PATCH 6/9] iomap: move the buffered " Darrick J. Wong
` (3 subsequent siblings)
8 siblings, 1 reply; 23+ messages in thread
From: Darrick J. Wong @ 2019-07-15 17:59 UTC (permalink / raw)
To: hch, darrick.wong; +Cc: linux-xfs, linux-fsdevel, agruenba
From: Darrick J. Wong <darrick.wong@oracle.com>
Move the direct IO code into a separate file so that we can group
related functions in a single file instead of having a single enormous
source file.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/iomap.c | 554 ------------------------------------------------
fs/iomap/Makefile | 1
fs/iomap/direct-io.c | 562 +++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/iomap.h | 7 +
4 files changed, 570 insertions(+), 554 deletions(-)
create mode 100644 fs/iomap/direct-io.c
diff --git a/fs/iomap.c b/fs/iomap.c
index ad994c408cb8..c983fedc7081 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -90,12 +90,6 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
return written ? written : ret;
}
-static sector_t
-iomap_sector(struct iomap *iomap, loff_t pos)
-{
- return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
-}
-
static struct iomap_page *
iomap_page_create(struct inode *inode, struct page *page)
{
@@ -1148,551 +1142,3 @@ vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops)
return block_page_mkwrite_return(ret);
}
EXPORT_SYMBOL_GPL(iomap_page_mkwrite);
-
-/*
- * 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;
- bool wait_for_completion;
-
- 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;
- };
-};
-
-int iomap_dio_iopoll(struct kiocb *kiocb, bool spin)
-{
- struct request_queue *q = READ_ONCE(kiocb->private);
-
- if (!q)
- return 0;
- return blk_poll(q, READ_ONCE(kiocb->ki_cookie), spin);
-}
-EXPORT_SYMBOL_GPL(iomap_dio_iopoll);
-
-static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap,
- struct bio *bio)
-{
- atomic_inc(&dio->ref);
-
- if (dio->iocb->ki_flags & IOCB_HIPRI)
- bio_set_polled(bio, dio->iocb);
-
- dio->submit.last_queue = bdev_get_queue(iomap->bdev);
- dio->submit.cookie = submit_bio(bio);
-}
-
-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 (dio->wait_for_completion) {
- struct task_struct *waiter = dio->submit.waiter;
- WRITE_ONCE(dio->submit.waiter, NULL);
- blk_wake_io_task(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 {
- bio_release_pages(bio, false);
- bio_put(bio);
- }
-}
-
-static void
-iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
- unsigned len)
-{
- struct page *page = ZERO_PAGE(0);
- int flags = REQ_SYNC | REQ_IDLE;
- 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, flags);
- iomap_dio_submit_bio(dio, iomap, bio);
-}
-
-static loff_t
-iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
- struct iomap_dio *dio, struct iomap *iomap)
-{
- 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 = 0;
- size_t copied = 0;
-
- if ((pos | length | align) & ((1 << blkbits) - 1))
- return -EINVAL;
-
- if (iomap->type == IOMAP_UNWRITTEN) {
- dio->flags |= IOMAP_DIO_UNWRITTEN;
- need_zeroout = true;
- }
-
- if (iomap->flags & IOMAP_F_SHARED)
- dio->flags |= IOMAP_DIO_COW;
-
- if (iomap->flags & IOMAP_F_NEW) {
- need_zeroout = true;
- } else if (iomap->type == IOMAP_MAPPED) {
- /*
- * Use a FUA write if we need datasync semantics, this is a pure
- * data IO that doesn't require any metadata updates (including
- * after IO completion such as unwritten extent conversion) 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;
- }
-
- /*
- * 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)) {
- /*
- * We have to stop part way through an IO. We must fall
- * through to the sub-block tail zeroing here, otherwise
- * this short IO may expose stale data in the tail of
- * the block we haven't written data to.
- */
- bio_put(bio);
- goto zero_tail;
- }
-
- 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);
- iomap_dio_submit_bio(dio, iomap, bio);
- } while (nr_pages);
-
- /*
- * We need to zeroout the tail of a sub-block write if the extent type
- * requires zeroing or the write extends beyond EOF. If we don't zero
- * the block tail in the latter case, we can expose stale data via mmap
- * reads of the EOF block.
- */
-zero_tail:
- if (need_zeroout ||
- ((dio->flags & IOMAP_DIO_WRITE) && pos >= i_size_read(inode))) {
- /* 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 ? copied : ret;
-}
-
-static loff_t
-iomap_dio_hole_actor(loff_t length, struct iomap_dio *dio)
-{
- length = iov_iter_zero(length, dio->submit.iter);
- dio->size += length;
- return length;
-}
-
-static loff_t
-iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length,
- struct iomap_dio *dio, struct iomap *iomap)
-{
- struct iov_iter *iter = dio->submit.iter;
- size_t copied;
-
- BUG_ON(pos + length > PAGE_SIZE - offset_in_page(iomap->inline_data));
-
- if (dio->flags & IOMAP_DIO_WRITE) {
- loff_t size = inode->i_size;
-
- if (pos > size)
- memset(iomap->inline_data + size, 0, pos - size);
- copied = copy_from_iter(iomap->inline_data + pos, length, iter);
- if (copied) {
- if (pos + copied > size)
- i_size_write(inode, pos + copied);
- mark_inode_dirty(inode);
- }
- } else {
- copied = copy_to_iter(iomap->inline_data + pos, length, iter);
- }
- dio->size += copied;
- return copied;
-}
-
-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;
-
- switch (iomap->type) {
- case IOMAP_HOLE:
- if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE))
- return -EIO;
- return iomap_dio_hole_actor(length, dio);
- case IOMAP_UNWRITTEN:
- if (!(dio->flags & IOMAP_DIO_WRITE))
- return iomap_dio_hole_actor(length, dio);
- return iomap_dio_bio_actor(inode, pos, length, dio, iomap);
- case IOMAP_MAPPED:
- return iomap_dio_bio_actor(inode, pos, length, dio, iomap);
- case IOMAP_INLINE:
- return iomap_dio_inline_actor(inode, pos, length, dio, iomap);
- default:
- WARN_ON_ONCE(1);
- return -EIO;
- }
-}
-
-/*
- * 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;
- bool wait_for_completion = is_sync_kiocb(iocb);
- 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;
- 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_is_iovec(iter) && iov_iter_rw(iter) == READ)
- 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 && !wait_for_completion &&
- !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) {
- wait_for_completion = true;
- 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;
-
- WRITE_ONCE(iocb->ki_cookie, dio->submit.cookie);
- WRITE_ONCE(iocb->private, dio->submit.last_queue);
-
- /*
- * We are about to drop our additional submission reference, which
- * might be the last reference to the dio. There are three three
- * different ways we can progress here:
- *
- * (a) If this is the last reference we will always complete and free
- * the dio ourselves.
- * (b) If this is not the last reference, and we serve an asynchronous
- * iocb, we must never touch the dio after the decrement, the
- * I/O completion handler will complete and free it.
- * (c) If this is not the last reference, but we serve a synchronous
- * iocb, the I/O completion handler will wake us up on the drop
- * of the final reference, and we will complete and free it here
- * after we got woken by the I/O completion handler.
- */
- dio->wait_for_completion = wait_for_completion;
- if (!atomic_dec_and_test(&dio->ref)) {
- if (!wait_for_completion)
- 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, true))
- io_schedule();
- }
- __set_current_state(TASK_RUNNING);
- }
-
- return iomap_dio_complete(dio);
-
-out_free_dio:
- kfree(dio);
- return ret;
-}
-EXPORT_SYMBOL_GPL(iomap_dio_rw);
diff --git a/fs/iomap/Makefile b/fs/iomap/Makefile
index 12dc7f844bbd..3e158f38b8e2 100644
--- a/fs/iomap/Makefile
+++ b/fs/iomap/Makefile
@@ -9,6 +9,7 @@ ccflags-y += -I $(srctree)/$(src)/..
obj-$(CONFIG_FS_IOMAP) += iomap.o
iomap-y += \
+ direct-io.o \
fiemap.o \
seek.o
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
new file mode 100644
index 000000000000..c99e5b085c34
--- /dev/null
+++ b/fs/iomap/direct-io.c
@@ -0,0 +1,562 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2010 Red Hat, Inc.
+ * Copyright (c) 2016-2018 Christoph Hellwig.
+ */
+#include <linux/module.h>
+#include <linux/compiler.h>
+#include <linux/fs.h>
+#include <linux/iomap.h>
+#include <linux/backing-dev.h>
+#include <linux/uio.h>
+#include <linux/task_io_accounting_ops.h>
+
+#include "internal.h"
+
+/*
+ * 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;
+ bool wait_for_completion;
+
+ 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;
+ };
+};
+
+int iomap_dio_iopoll(struct kiocb *kiocb, bool spin)
+{
+ struct request_queue *q = READ_ONCE(kiocb->private);
+
+ if (!q)
+ return 0;
+ return blk_poll(q, READ_ONCE(kiocb->ki_cookie), spin);
+}
+EXPORT_SYMBOL_GPL(iomap_dio_iopoll);
+
+static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap,
+ struct bio *bio)
+{
+ atomic_inc(&dio->ref);
+
+ if (dio->iocb->ki_flags & IOCB_HIPRI)
+ bio_set_polled(bio, dio->iocb);
+
+ dio->submit.last_queue = bdev_get_queue(iomap->bdev);
+ dio->submit.cookie = submit_bio(bio);
+}
+
+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 (dio->wait_for_completion) {
+ struct task_struct *waiter = dio->submit.waiter;
+ WRITE_ONCE(dio->submit.waiter, NULL);
+ blk_wake_io_task(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 {
+ bio_release_pages(bio, false);
+ bio_put(bio);
+ }
+}
+
+static void
+iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
+ unsigned len)
+{
+ struct page *page = ZERO_PAGE(0);
+ int flags = REQ_SYNC | REQ_IDLE;
+ 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, flags);
+ iomap_dio_submit_bio(dio, iomap, bio);
+}
+
+static loff_t
+iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
+ struct iomap_dio *dio, struct iomap *iomap)
+{
+ 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 = 0;
+ size_t copied = 0;
+
+ if ((pos | length | align) & ((1 << blkbits) - 1))
+ return -EINVAL;
+
+ if (iomap->type == IOMAP_UNWRITTEN) {
+ dio->flags |= IOMAP_DIO_UNWRITTEN;
+ need_zeroout = true;
+ }
+
+ if (iomap->flags & IOMAP_F_SHARED)
+ dio->flags |= IOMAP_DIO_COW;
+
+ if (iomap->flags & IOMAP_F_NEW) {
+ need_zeroout = true;
+ } else if (iomap->type == IOMAP_MAPPED) {
+ /*
+ * Use a FUA write if we need datasync semantics, this is a pure
+ * data IO that doesn't require any metadata updates (including
+ * after IO completion such as unwritten extent conversion) 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;
+ }
+
+ /*
+ * 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)) {
+ /*
+ * We have to stop part way through an IO. We must fall
+ * through to the sub-block tail zeroing here, otherwise
+ * this short IO may expose stale data in the tail of
+ * the block we haven't written data to.
+ */
+ bio_put(bio);
+ goto zero_tail;
+ }
+
+ 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);
+ iomap_dio_submit_bio(dio, iomap, bio);
+ } while (nr_pages);
+
+ /*
+ * We need to zeroout the tail of a sub-block write if the extent type
+ * requires zeroing or the write extends beyond EOF. If we don't zero
+ * the block tail in the latter case, we can expose stale data via mmap
+ * reads of the EOF block.
+ */
+zero_tail:
+ if (need_zeroout ||
+ ((dio->flags & IOMAP_DIO_WRITE) && pos >= i_size_read(inode))) {
+ /* 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 ? copied : ret;
+}
+
+static loff_t
+iomap_dio_hole_actor(loff_t length, struct iomap_dio *dio)
+{
+ length = iov_iter_zero(length, dio->submit.iter);
+ dio->size += length;
+ return length;
+}
+
+static loff_t
+iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length,
+ struct iomap_dio *dio, struct iomap *iomap)
+{
+ struct iov_iter *iter = dio->submit.iter;
+ size_t copied;
+
+ BUG_ON(pos + length > PAGE_SIZE - offset_in_page(iomap->inline_data));
+
+ if (dio->flags & IOMAP_DIO_WRITE) {
+ loff_t size = inode->i_size;
+
+ if (pos > size)
+ memset(iomap->inline_data + size, 0, pos - size);
+ copied = copy_from_iter(iomap->inline_data + pos, length, iter);
+ if (copied) {
+ if (pos + copied > size)
+ i_size_write(inode, pos + copied);
+ mark_inode_dirty(inode);
+ }
+ } else {
+ copied = copy_to_iter(iomap->inline_data + pos, length, iter);
+ }
+ dio->size += copied;
+ return copied;
+}
+
+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;
+
+ switch (iomap->type) {
+ case IOMAP_HOLE:
+ if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE))
+ return -EIO;
+ return iomap_dio_hole_actor(length, dio);
+ case IOMAP_UNWRITTEN:
+ if (!(dio->flags & IOMAP_DIO_WRITE))
+ return iomap_dio_hole_actor(length, dio);
+ return iomap_dio_bio_actor(inode, pos, length, dio, iomap);
+ case IOMAP_MAPPED:
+ return iomap_dio_bio_actor(inode, pos, length, dio, iomap);
+ case IOMAP_INLINE:
+ return iomap_dio_inline_actor(inode, pos, length, dio, iomap);
+ default:
+ WARN_ON_ONCE(1);
+ return -EIO;
+ }
+}
+
+/*
+ * 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;
+ bool wait_for_completion = is_sync_kiocb(iocb);
+ 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;
+ 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_is_iovec(iter) && iov_iter_rw(iter) == READ)
+ 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 && !wait_for_completion &&
+ !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) {
+ wait_for_completion = true;
+ 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;
+
+ WRITE_ONCE(iocb->ki_cookie, dio->submit.cookie);
+ WRITE_ONCE(iocb->private, dio->submit.last_queue);
+
+ /*
+ * We are about to drop our additional submission reference, which
+ * might be the last reference to the dio. There are three three
+ * different ways we can progress here:
+ *
+ * (a) If this is the last reference we will always complete and free
+ * the dio ourselves.
+ * (b) If this is not the last reference, and we serve an asynchronous
+ * iocb, we must never touch the dio after the decrement, the
+ * I/O completion handler will complete and free it.
+ * (c) If this is not the last reference, but we serve a synchronous
+ * iocb, the I/O completion handler will wake us up on the drop
+ * of the final reference, and we will complete and free it here
+ * after we got woken by the I/O completion handler.
+ */
+ dio->wait_for_completion = wait_for_completion;
+ if (!atomic_dec_and_test(&dio->ref)) {
+ if (!wait_for_completion)
+ 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, true))
+ io_schedule();
+ }
+ __set_current_state(TASK_RUNNING);
+ }
+
+ return iomap_dio_complete(dio);
+
+out_free_dio:
+ kfree(dio);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(iomap_dio_rw);
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 1df9ea187a9a..baa1e2d31f05 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -7,6 +7,7 @@
#include <linux/mm.h>
#include <linux/types.h>
#include <linux/mm_types.h>
+#include <linux/blkdev.h>
struct address_space;
struct fiemap_extent_info;
@@ -69,6 +70,12 @@ struct iomap {
const struct iomap_page_ops *page_ops;
};
+static inline sector_t
+iomap_sector(struct iomap *iomap, loff_t pos)
+{
+ return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
+}
+
/*
* When a filesystem sets page_ops in an iomap mapping it returns, page_prepare
* and page_done will be called for each page written to. This only applies to
^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH 6/9] iomap: move the buffered IO code into a separate file
2019-07-15 17:59 [PATCH v2 0/9] iomap: regroup code by functional area Darrick J. Wong
` (4 preceding siblings ...)
2019-07-15 17:59 ` [PATCH 5/9] iomap: move the direct IO " Darrick J. Wong
@ 2019-07-15 17:59 ` Darrick J. Wong
2019-07-17 5:03 ` Christoph Hellwig
2019-07-15 18:00 ` [PATCH 7/9] iomap: move the page migration " Darrick J. Wong
` (2 subsequent siblings)
8 siblings, 1 reply; 23+ messages in thread
From: Darrick J. Wong @ 2019-07-15 17:59 UTC (permalink / raw)
To: hch, darrick.wong; +Cc: linux-xfs, linux-fsdevel, agruenba
From: Darrick J. Wong <darrick.wong@oracle.com>
Move the buffered IO code into a separate file so that we can group
related functions in a single file instead of having a single enormous
source file.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/iomap.c | 1024 -----------------------------------------------
fs/iomap/Makefile | 1
fs/iomap/buffered-io.c | 1043 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 1044 insertions(+), 1024 deletions(-)
create mode 100644 fs/iomap/buffered-io.c
diff --git a/fs/iomap.c b/fs/iomap.c
index c983fedc7081..ab658a4b97d3 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -90,469 +90,6 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
return written ? written : ret;
}
-static struct iomap_page *
-iomap_page_create(struct inode *inode, struct page *page)
-{
- struct iomap_page *iop = to_iomap_page(page);
-
- if (iop || i_blocksize(inode) == PAGE_SIZE)
- return iop;
-
- iop = kmalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL);
- atomic_set(&iop->read_count, 0);
- atomic_set(&iop->write_count, 0);
- bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE);
-
- /*
- * migrate_page_move_mapping() assumes that pages with private data have
- * their count elevated by 1.
- */
- get_page(page);
- set_page_private(page, (unsigned long)iop);
- SetPagePrivate(page);
- return iop;
-}
-
-static void
-iomap_page_release(struct page *page)
-{
- struct iomap_page *iop = to_iomap_page(page);
-
- if (!iop)
- return;
- WARN_ON_ONCE(atomic_read(&iop->read_count));
- WARN_ON_ONCE(atomic_read(&iop->write_count));
- ClearPagePrivate(page);
- set_page_private(page, 0);
- put_page(page);
- kfree(iop);
-}
-
-/*
- * Calculate the range inside the page that we actually need to read.
- */
-static void
-iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
- loff_t *pos, loff_t length, unsigned *offp, unsigned *lenp)
-{
- loff_t orig_pos = *pos;
- loff_t isize = i_size_read(inode);
- unsigned block_bits = inode->i_blkbits;
- unsigned block_size = (1 << block_bits);
- unsigned poff = offset_in_page(*pos);
- unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length);
- unsigned first = poff >> block_bits;
- unsigned last = (poff + plen - 1) >> block_bits;
-
- /*
- * If the block size is smaller than the page size we need to check the
- * per-block uptodate status and adjust the offset and length if needed
- * to avoid reading in already uptodate ranges.
- */
- if (iop) {
- unsigned int i;
-
- /* move forward for each leading block marked uptodate */
- for (i = first; i <= last; i++) {
- if (!test_bit(i, iop->uptodate))
- break;
- *pos += block_size;
- poff += block_size;
- plen -= block_size;
- first++;
- }
-
- /* truncate len if we find any trailing uptodate block(s) */
- for ( ; i <= last; i++) {
- if (test_bit(i, iop->uptodate)) {
- plen -= (last - i + 1) * block_size;
- last = i - 1;
- break;
- }
- }
- }
-
- /*
- * If the extent spans the block that contains the i_size we need to
- * handle both halves separately so that we properly zero data in the
- * page cache for blocks that are entirely outside of i_size.
- */
- if (orig_pos <= isize && orig_pos + length > isize) {
- unsigned end = offset_in_page(isize - 1) >> block_bits;
-
- if (first <= end && last > end)
- plen -= (last - end) * block_size;
- }
-
- *offp = poff;
- *lenp = plen;
-}
-
-static void
-iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len)
-{
- struct iomap_page *iop = to_iomap_page(page);
- struct inode *inode = page->mapping->host;
- unsigned first = off >> inode->i_blkbits;
- unsigned last = (off + len - 1) >> inode->i_blkbits;
- unsigned int i;
- bool uptodate = true;
-
- if (iop) {
- for (i = 0; i < PAGE_SIZE / i_blocksize(inode); i++) {
- if (i >= first && i <= last)
- set_bit(i, iop->uptodate);
- else if (!test_bit(i, iop->uptodate))
- uptodate = false;
- }
- }
-
- if (uptodate && !PageError(page))
- SetPageUptodate(page);
-}
-
-static void
-iomap_read_finish(struct iomap_page *iop, struct page *page)
-{
- if (!iop || atomic_dec_and_test(&iop->read_count))
- unlock_page(page);
-}
-
-static void
-iomap_read_page_end_io(struct bio_vec *bvec, int error)
-{
- struct page *page = bvec->bv_page;
- struct iomap_page *iop = to_iomap_page(page);
-
- if (unlikely(error)) {
- ClearPageUptodate(page);
- SetPageError(page);
- } else {
- iomap_set_range_uptodate(page, bvec->bv_offset, bvec->bv_len);
- }
-
- iomap_read_finish(iop, page);
-}
-
-static void
-iomap_read_end_io(struct bio *bio)
-{
- int error = blk_status_to_errno(bio->bi_status);
- struct bio_vec *bvec;
- struct bvec_iter_all iter_all;
-
- bio_for_each_segment_all(bvec, bio, iter_all)
- iomap_read_page_end_io(bvec, error);
- bio_put(bio);
-}
-
-struct iomap_readpage_ctx {
- struct page *cur_page;
- bool cur_page_in_bio;
- bool is_readahead;
- struct bio *bio;
- struct list_head *pages;
-};
-
-static void
-iomap_read_inline_data(struct inode *inode, struct page *page,
- struct iomap *iomap)
-{
- size_t size = i_size_read(inode);
- void *addr;
-
- if (PageUptodate(page))
- return;
-
- BUG_ON(page->index);
- BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data));
-
- addr = kmap_atomic(page);
- memcpy(addr, iomap->inline_data, size);
- memset(addr + size, 0, PAGE_SIZE - size);
- kunmap_atomic(addr);
- SetPageUptodate(page);
-}
-
-static loff_t
-iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
- struct iomap *iomap)
-{
- struct iomap_readpage_ctx *ctx = data;
- struct page *page = ctx->cur_page;
- struct iomap_page *iop = iomap_page_create(inode, page);
- bool same_page = false, is_contig = false;
- loff_t orig_pos = pos;
- unsigned poff, plen;
- sector_t sector;
-
- if (iomap->type == IOMAP_INLINE) {
- WARN_ON_ONCE(pos);
- iomap_read_inline_data(inode, page, iomap);
- return PAGE_SIZE;
- }
-
- /* zero post-eof blocks as the page may be mapped */
- iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen);
- if (plen == 0)
- goto done;
-
- if (iomap->type != IOMAP_MAPPED || pos >= i_size_read(inode)) {
- zero_user(page, poff, plen);
- iomap_set_range_uptodate(page, poff, plen);
- goto done;
- }
-
- ctx->cur_page_in_bio = true;
-
- /*
- * Try to merge into a previous segment if we can.
- */
- sector = iomap_sector(iomap, pos);
- if (ctx->bio && bio_end_sector(ctx->bio) == sector)
- is_contig = true;
-
- if (is_contig &&
- __bio_try_merge_page(ctx->bio, page, plen, poff, &same_page)) {
- if (!same_page && iop)
- atomic_inc(&iop->read_count);
- goto done;
- }
-
- /*
- * If we start a new segment we need to increase the read count, and we
- * need to do so before submitting any previous full bio to make sure
- * that we don't prematurely unlock the page.
- */
- if (iop)
- atomic_inc(&iop->read_count);
-
- if (!ctx->bio || !is_contig || bio_full(ctx->bio, plen)) {
- gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
- int nr_vecs = (length + PAGE_SIZE - 1) >> PAGE_SHIFT;
-
- if (ctx->bio)
- submit_bio(ctx->bio);
-
- if (ctx->is_readahead) /* same as readahead_gfp_mask */
- gfp |= __GFP_NORETRY | __GFP_NOWARN;
- ctx->bio = bio_alloc(gfp, min(BIO_MAX_PAGES, nr_vecs));
- ctx->bio->bi_opf = REQ_OP_READ;
- if (ctx->is_readahead)
- ctx->bio->bi_opf |= REQ_RAHEAD;
- ctx->bio->bi_iter.bi_sector = sector;
- bio_set_dev(ctx->bio, iomap->bdev);
- ctx->bio->bi_end_io = iomap_read_end_io;
- }
-
- bio_add_page(ctx->bio, page, plen, poff);
-done:
- /*
- * Move the caller beyond our range so that it keeps making progress.
- * For that we have to include any leading non-uptodate ranges, but
- * we can skip trailing ones as they will be handled in the next
- * iteration.
- */
- return pos - orig_pos + plen;
-}
-
-int
-iomap_readpage(struct page *page, const struct iomap_ops *ops)
-{
- struct iomap_readpage_ctx ctx = { .cur_page = page };
- struct inode *inode = page->mapping->host;
- unsigned poff;
- loff_t ret;
-
- for (poff = 0; poff < PAGE_SIZE; poff += ret) {
- ret = iomap_apply(inode, page_offset(page) + poff,
- PAGE_SIZE - poff, 0, ops, &ctx,
- iomap_readpage_actor);
- if (ret <= 0) {
- WARN_ON_ONCE(ret == 0);
- SetPageError(page);
- break;
- }
- }
-
- if (ctx.bio) {
- submit_bio(ctx.bio);
- WARN_ON_ONCE(!ctx.cur_page_in_bio);
- } else {
- WARN_ON_ONCE(ctx.cur_page_in_bio);
- unlock_page(page);
- }
-
- /*
- * Just like mpage_readpages and block_read_full_page we always
- * return 0 and just mark the page as PageError on errors. This
- * should be cleaned up all through the stack eventually.
- */
- return 0;
-}
-EXPORT_SYMBOL_GPL(iomap_readpage);
-
-static struct page *
-iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos,
- loff_t length, loff_t *done)
-{
- while (!list_empty(pages)) {
- struct page *page = lru_to_page(pages);
-
- if (page_offset(page) >= (u64)pos + length)
- break;
-
- list_del(&page->lru);
- if (!add_to_page_cache_lru(page, inode->i_mapping, page->index,
- GFP_NOFS))
- return page;
-
- /*
- * If we already have a page in the page cache at index we are
- * done. Upper layers don't care if it is uptodate after the
- * readpages call itself as every page gets checked again once
- * actually needed.
- */
- *done += PAGE_SIZE;
- put_page(page);
- }
-
- return NULL;
-}
-
-static loff_t
-iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length,
- void *data, struct iomap *iomap)
-{
- struct iomap_readpage_ctx *ctx = data;
- loff_t done, ret;
-
- for (done = 0; done < length; done += ret) {
- if (ctx->cur_page && offset_in_page(pos + done) == 0) {
- if (!ctx->cur_page_in_bio)
- unlock_page(ctx->cur_page);
- put_page(ctx->cur_page);
- ctx->cur_page = NULL;
- }
- if (!ctx->cur_page) {
- ctx->cur_page = iomap_next_page(inode, ctx->pages,
- pos, length, &done);
- if (!ctx->cur_page)
- break;
- ctx->cur_page_in_bio = false;
- }
- ret = iomap_readpage_actor(inode, pos + done, length - done,
- ctx, iomap);
- }
-
- return done;
-}
-
-int
-iomap_readpages(struct address_space *mapping, struct list_head *pages,
- unsigned nr_pages, const struct iomap_ops *ops)
-{
- struct iomap_readpage_ctx ctx = {
- .pages = pages,
- .is_readahead = true,
- };
- loff_t pos = page_offset(list_entry(pages->prev, struct page, lru));
- loff_t last = page_offset(list_entry(pages->next, struct page, lru));
- loff_t length = last - pos + PAGE_SIZE, ret = 0;
-
- while (length > 0) {
- ret = iomap_apply(mapping->host, pos, length, 0, ops,
- &ctx, iomap_readpages_actor);
- if (ret <= 0) {
- WARN_ON_ONCE(ret == 0);
- goto done;
- }
- pos += ret;
- length -= ret;
- }
- ret = 0;
-done:
- if (ctx.bio)
- submit_bio(ctx.bio);
- if (ctx.cur_page) {
- if (!ctx.cur_page_in_bio)
- unlock_page(ctx.cur_page);
- put_page(ctx.cur_page);
- }
-
- /*
- * Check that we didn't lose a page due to the arcance calling
- * conventions..
- */
- WARN_ON_ONCE(!ret && !list_empty(ctx.pages));
- return ret;
-}
-EXPORT_SYMBOL_GPL(iomap_readpages);
-
-/*
- * iomap_is_partially_uptodate checks whether blocks within a page are
- * uptodate or not.
- *
- * Returns true if all blocks which correspond to a file portion
- * we want to read within the page are uptodate.
- */
-int
-iomap_is_partially_uptodate(struct page *page, unsigned long from,
- unsigned long count)
-{
- struct iomap_page *iop = to_iomap_page(page);
- struct inode *inode = page->mapping->host;
- unsigned len, first, last;
- unsigned i;
-
- /* Limit range to one page */
- len = min_t(unsigned, PAGE_SIZE - from, count);
-
- /* First and last blocks in range within page */
- first = from >> inode->i_blkbits;
- last = (from + len - 1) >> inode->i_blkbits;
-
- if (iop) {
- for (i = first; i <= last; i++)
- if (!test_bit(i, iop->uptodate))
- return 0;
- return 1;
- }
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(iomap_is_partially_uptodate);
-
-int
-iomap_releasepage(struct page *page, gfp_t gfp_mask)
-{
- /*
- * mm accommodates an old ext3 case where clean pages might not have had
- * the dirty bit cleared. Thus, it can send actual dirty pages to
- * ->releasepage() via shrink_active_list(), skip those here.
- */
- if (PageDirty(page) || PageWriteback(page))
- return 0;
- iomap_page_release(page);
- return 1;
-}
-EXPORT_SYMBOL_GPL(iomap_releasepage);
-
-void
-iomap_invalidatepage(struct page *page, unsigned int offset, unsigned int len)
-{
- /*
- * If we are invalidating the entire page, clear the dirty state from it
- * and release it to avoid unnecessary buildup of the LRU.
- */
- if (offset == 0 && len == PAGE_SIZE) {
- WARN_ON_ONCE(PageWriteback(page));
- cancel_dirty_page(page);
- iomap_page_release(page);
- }
-}
-EXPORT_SYMBOL_GPL(iomap_invalidatepage);
-
#ifdef CONFIG_MIGRATION
int
iomap_migrate_page(struct address_space *mapping, struct page *newpage,
@@ -581,564 +118,3 @@ iomap_migrate_page(struct address_space *mapping, struct page *newpage,
}
EXPORT_SYMBOL_GPL(iomap_migrate_page);
#endif /* CONFIG_MIGRATION */
-
-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_read_page_sync(struct inode *inode, loff_t block_start, struct page *page,
- unsigned poff, unsigned plen, unsigned from, unsigned to,
- struct iomap *iomap)
-{
- struct bio_vec bvec;
- struct bio bio;
-
- if (iomap->type != IOMAP_MAPPED || block_start >= i_size_read(inode)) {
- zero_user_segments(page, poff, from, to, poff + plen);
- iomap_set_range_uptodate(page, poff, plen);
- return 0;
- }
-
- bio_init(&bio, &bvec, 1);
- bio.bi_opf = REQ_OP_READ;
- bio.bi_iter.bi_sector = iomap_sector(iomap, block_start);
- bio_set_dev(&bio, iomap->bdev);
- __bio_add_page(&bio, page, plen, poff);
- return submit_bio_wait(&bio);
-}
-
-static int
-__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len,
- struct page *page, struct iomap *iomap)
-{
- struct iomap_page *iop = iomap_page_create(inode, page);
- loff_t block_size = i_blocksize(inode);
- loff_t block_start = pos & ~(block_size - 1);
- loff_t block_end = (pos + len + block_size - 1) & ~(block_size - 1);
- unsigned from = offset_in_page(pos), to = from + len, poff, plen;
- int status = 0;
-
- if (PageUptodate(page))
- return 0;
-
- do {
- iomap_adjust_read_range(inode, iop, &block_start,
- block_end - block_start, &poff, &plen);
- if (plen == 0)
- break;
-
- if ((from > poff && from < poff + plen) ||
- (to > poff && to < poff + plen)) {
- status = iomap_read_page_sync(inode, block_start, page,
- poff, plen, from, to, iomap);
- if (status)
- break;
- }
-
- } while ((block_start += plen) < block_end);
-
- return status;
-}
-
-static int
-iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
- struct page **pagep, struct iomap *iomap)
-{
- const struct iomap_page_ops *page_ops = iomap->page_ops;
- 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;
-
- if (page_ops && page_ops->page_prepare) {
- status = page_ops->page_prepare(inode, pos, len, iomap);
- if (status)
- return status;
- }
-
- page = grab_cache_page_write_begin(inode->i_mapping, index, flags);
- if (!page) {
- status = -ENOMEM;
- goto out_no_page;
- }
-
- if (iomap->type == IOMAP_INLINE)
- iomap_read_inline_data(inode, page, iomap);
- else if (iomap->flags & IOMAP_F_BUFFER_HEAD)
- status = __block_write_begin_int(page, pos, len, NULL, iomap);
- else
- status = __iomap_write_begin(inode, pos, len, page, iomap);
-
- if (unlikely(status))
- goto out_unlock;
-
- *pagep = page;
- return 0;
-
-out_unlock:
- unlock_page(page);
- put_page(page);
- iomap_write_failed(inode, pos, len);
-
-out_no_page:
- if (page_ops && page_ops->page_done)
- page_ops->page_done(inode, pos, 0, NULL, iomap);
- return status;
-}
-
-int
-iomap_set_page_dirty(struct page *page)
-{
- struct address_space *mapping = page_mapping(page);
- int newly_dirty;
-
- if (unlikely(!mapping))
- return !TestSetPageDirty(page);
-
- /*
- * Lock out page->mem_cgroup migration to keep PageDirty
- * synchronized with per-memcg dirty page counters.
- */
- lock_page_memcg(page);
- newly_dirty = !TestSetPageDirty(page);
- if (newly_dirty)
- __set_page_dirty(page, mapping, 0);
- unlock_page_memcg(page);
-
- if (newly_dirty)
- __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
- return newly_dirty;
-}
-EXPORT_SYMBOL_GPL(iomap_set_page_dirty);
-
-static int
-__iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
- unsigned copied, struct page *page, struct iomap *iomap)
-{
- flush_dcache_page(page);
-
- /*
- * The blocks that were entirely written will now be uptodate, so we
- * don't have to worry about a readpage reading them and overwriting a
- * partial write. However if we have encountered a short write and only
- * partially written into a block, it will not be marked uptodate, so a
- * readpage might come in and destroy our partial write.
- *
- * Do the simplest thing, and just treat any short write to a non
- * uptodate page as a zero-length write, and force the caller to redo
- * the whole thing.
- */
- if (unlikely(copied < len && !PageUptodate(page)))
- return 0;
- iomap_set_range_uptodate(page, offset_in_page(pos), len);
- iomap_set_page_dirty(page);
- return copied;
-}
-
-static int
-iomap_write_end_inline(struct inode *inode, struct page *page,
- struct iomap *iomap, loff_t pos, unsigned copied)
-{
- void *addr;
-
- WARN_ON_ONCE(!PageUptodate(page));
- BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data));
-
- addr = kmap_atomic(page);
- memcpy(iomap->inline_data + pos, addr + pos, copied);
- kunmap_atomic(addr);
-
- mark_inode_dirty(inode);
- return copied;
-}
-
-static int
-iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
- unsigned copied, struct page *page, struct iomap *iomap)
-{
- const struct iomap_page_ops *page_ops = iomap->page_ops;
- loff_t old_size = inode->i_size;
- int ret;
-
- if (iomap->type == IOMAP_INLINE) {
- ret = iomap_write_end_inline(inode, page, iomap, pos, copied);
- } else if (iomap->flags & IOMAP_F_BUFFER_HEAD) {
- ret = block_write_end(NULL, inode->i_mapping, pos, len, copied,
- page, NULL);
- } else {
- ret = __iomap_write_end(inode, pos, len, copied, page, iomap);
- }
-
- /*
- * Update the in-memory inode size after copying the data into the page
- * cache. It's up to the file system to write the updated size to disk,
- * preferably after I/O completion so that no stale data is exposed.
- */
- if (pos + ret > old_size) {
- i_size_write(inode, pos + ret);
- iomap->flags |= IOMAP_F_SIZE_CHANGED;
- }
- unlock_page(page);
-
- if (old_size < pos)
- pagecache_isize_extended(inode, old_size, pos);
- if (page_ops && page_ops->page_done)
- page_ops->page_done(inode, pos, ret, page, iomap);
- put_page(page);
-
- 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 = offset_in_page(pos);
- 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,
- iomap);
- 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 = offset_in_page(pos);
- 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, iomap);
- 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, iomap);
-}
-
-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 = offset_in_page(pos);
- 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;
-
- if (iomap->flags & IOMAP_F_BUFFER_HEAD) {
- ret = __block_write_begin_int(page, pos, length, NULL, iomap);
- if (ret)
- return ret;
- block_commit_write(page, 0, length);
- } else {
- WARN_ON_ONCE(!PageUptodate(page));
- iomap_page_create(inode, page);
- set_page_dirty(page);
- }
-
- return length;
-}
-
-vm_fault_t 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 = offset_in_page(size);
- 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;
- }
-
- 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);
diff --git a/fs/iomap/Makefile b/fs/iomap/Makefile
index 3e158f38b8e2..d2a81819ae01 100644
--- a/fs/iomap/Makefile
+++ b/fs/iomap/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_FS_IOMAP) += iomap.o
iomap-y += \
direct-io.o \
+ buffered-io.o \
fiemap.o \
seek.o
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
new file mode 100644
index 000000000000..eafc76b65de7
--- /dev/null
+++ b/fs/iomap/buffered-io.c
@@ -0,0 +1,1043 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2010 Red Hat, Inc.
+ * Copyright (c) 2016-2018 Christoph Hellwig.
+ */
+#include <linux/module.h>
+#include <linux/compiler.h>
+#include <linux/fs.h>
+#include <linux/iomap.h>
+#include <linux/pagemap.h>
+#include <linux/uio.h>
+#include <linux/buffer_head.h>
+#include <linux/dax.h>
+#include <linux/writeback.h>
+#include <linux/swap.h>
+#include <linux/bio.h>
+#include <linux/sched/signal.h>
+
+#include "internal.h"
+
+static struct iomap_page *
+iomap_page_create(struct inode *inode, struct page *page)
+{
+ struct iomap_page *iop = to_iomap_page(page);
+
+ if (iop || i_blocksize(inode) == PAGE_SIZE)
+ return iop;
+
+ iop = kmalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL);
+ atomic_set(&iop->read_count, 0);
+ atomic_set(&iop->write_count, 0);
+ bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE);
+
+ /*
+ * migrate_page_move_mapping() assumes that pages with private data have
+ * their count elevated by 1.
+ */
+ get_page(page);
+ set_page_private(page, (unsigned long)iop);
+ SetPagePrivate(page);
+ return iop;
+}
+
+static void
+iomap_page_release(struct page *page)
+{
+ struct iomap_page *iop = to_iomap_page(page);
+
+ if (!iop)
+ return;
+ WARN_ON_ONCE(atomic_read(&iop->read_count));
+ WARN_ON_ONCE(atomic_read(&iop->write_count));
+ ClearPagePrivate(page);
+ set_page_private(page, 0);
+ put_page(page);
+ kfree(iop);
+}
+
+/*
+ * Calculate the range inside the page that we actually need to read.
+ */
+static void
+iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
+ loff_t *pos, loff_t length, unsigned *offp, unsigned *lenp)
+{
+ loff_t orig_pos = *pos;
+ loff_t isize = i_size_read(inode);
+ unsigned block_bits = inode->i_blkbits;
+ unsigned block_size = (1 << block_bits);
+ unsigned poff = offset_in_page(*pos);
+ unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length);
+ unsigned first = poff >> block_bits;
+ unsigned last = (poff + plen - 1) >> block_bits;
+
+ /*
+ * If the block size is smaller than the page size we need to check the
+ * per-block uptodate status and adjust the offset and length if needed
+ * to avoid reading in already uptodate ranges.
+ */
+ if (iop) {
+ unsigned int i;
+
+ /* move forward for each leading block marked uptodate */
+ for (i = first; i <= last; i++) {
+ if (!test_bit(i, iop->uptodate))
+ break;
+ *pos += block_size;
+ poff += block_size;
+ plen -= block_size;
+ first++;
+ }
+
+ /* truncate len if we find any trailing uptodate block(s) */
+ for ( ; i <= last; i++) {
+ if (test_bit(i, iop->uptodate)) {
+ plen -= (last - i + 1) * block_size;
+ last = i - 1;
+ break;
+ }
+ }
+ }
+
+ /*
+ * If the extent spans the block that contains the i_size we need to
+ * handle both halves separately so that we properly zero data in the
+ * page cache for blocks that are entirely outside of i_size.
+ */
+ if (orig_pos <= isize && orig_pos + length > isize) {
+ unsigned end = offset_in_page(isize - 1) >> block_bits;
+
+ if (first <= end && last > end)
+ plen -= (last - end) * block_size;
+ }
+
+ *offp = poff;
+ *lenp = plen;
+}
+
+static void
+iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len)
+{
+ struct iomap_page *iop = to_iomap_page(page);
+ struct inode *inode = page->mapping->host;
+ unsigned first = off >> inode->i_blkbits;
+ unsigned last = (off + len - 1) >> inode->i_blkbits;
+ unsigned int i;
+ bool uptodate = true;
+
+ if (iop) {
+ for (i = 0; i < PAGE_SIZE / i_blocksize(inode); i++) {
+ if (i >= first && i <= last)
+ set_bit(i, iop->uptodate);
+ else if (!test_bit(i, iop->uptodate))
+ uptodate = false;
+ }
+ }
+
+ if (uptodate && !PageError(page))
+ SetPageUptodate(page);
+}
+
+static void
+iomap_read_finish(struct iomap_page *iop, struct page *page)
+{
+ if (!iop || atomic_dec_and_test(&iop->read_count))
+ unlock_page(page);
+}
+
+static void
+iomap_read_page_end_io(struct bio_vec *bvec, int error)
+{
+ struct page *page = bvec->bv_page;
+ struct iomap_page *iop = to_iomap_page(page);
+
+ if (unlikely(error)) {
+ ClearPageUptodate(page);
+ SetPageError(page);
+ } else {
+ iomap_set_range_uptodate(page, bvec->bv_offset, bvec->bv_len);
+ }
+
+ iomap_read_finish(iop, page);
+}
+
+static void
+iomap_read_end_io(struct bio *bio)
+{
+ int error = blk_status_to_errno(bio->bi_status);
+ struct bio_vec *bvec;
+ struct bvec_iter_all iter_all;
+
+ bio_for_each_segment_all(bvec, bio, iter_all)
+ iomap_read_page_end_io(bvec, error);
+ bio_put(bio);
+}
+
+struct iomap_readpage_ctx {
+ struct page *cur_page;
+ bool cur_page_in_bio;
+ bool is_readahead;
+ struct bio *bio;
+ struct list_head *pages;
+};
+
+static void
+iomap_read_inline_data(struct inode *inode, struct page *page,
+ struct iomap *iomap)
+{
+ size_t size = i_size_read(inode);
+ void *addr;
+
+ if (PageUptodate(page))
+ return;
+
+ BUG_ON(page->index);
+ BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data));
+
+ addr = kmap_atomic(page);
+ memcpy(addr, iomap->inline_data, size);
+ memset(addr + size, 0, PAGE_SIZE - size);
+ kunmap_atomic(addr);
+ SetPageUptodate(page);
+}
+
+static loff_t
+iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
+ struct iomap *iomap)
+{
+ struct iomap_readpage_ctx *ctx = data;
+ struct page *page = ctx->cur_page;
+ struct iomap_page *iop = iomap_page_create(inode, page);
+ bool same_page = false, is_contig = false;
+ loff_t orig_pos = pos;
+ unsigned poff, plen;
+ sector_t sector;
+
+ if (iomap->type == IOMAP_INLINE) {
+ WARN_ON_ONCE(pos);
+ iomap_read_inline_data(inode, page, iomap);
+ return PAGE_SIZE;
+ }
+
+ /* zero post-eof blocks as the page may be mapped */
+ iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen);
+ if (plen == 0)
+ goto done;
+
+ if (iomap->type != IOMAP_MAPPED || pos >= i_size_read(inode)) {
+ zero_user(page, poff, plen);
+ iomap_set_range_uptodate(page, poff, plen);
+ goto done;
+ }
+
+ ctx->cur_page_in_bio = true;
+
+ /*
+ * Try to merge into a previous segment if we can.
+ */
+ sector = iomap_sector(iomap, pos);
+ if (ctx->bio && bio_end_sector(ctx->bio) == sector)
+ is_contig = true;
+
+ if (is_contig &&
+ __bio_try_merge_page(ctx->bio, page, plen, poff, &same_page)) {
+ if (!same_page && iop)
+ atomic_inc(&iop->read_count);
+ goto done;
+ }
+
+ /*
+ * If we start a new segment we need to increase the read count, and we
+ * need to do so before submitting any previous full bio to make sure
+ * that we don't prematurely unlock the page.
+ */
+ if (iop)
+ atomic_inc(&iop->read_count);
+
+ if (!ctx->bio || !is_contig || bio_full(ctx->bio, plen)) {
+ gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
+ int nr_vecs = (length + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
+ if (ctx->bio)
+ submit_bio(ctx->bio);
+
+ if (ctx->is_readahead) /* same as readahead_gfp_mask */
+ gfp |= __GFP_NORETRY | __GFP_NOWARN;
+ ctx->bio = bio_alloc(gfp, min(BIO_MAX_PAGES, nr_vecs));
+ ctx->bio->bi_opf = REQ_OP_READ;
+ if (ctx->is_readahead)
+ ctx->bio->bi_opf |= REQ_RAHEAD;
+ ctx->bio->bi_iter.bi_sector = sector;
+ bio_set_dev(ctx->bio, iomap->bdev);
+ ctx->bio->bi_end_io = iomap_read_end_io;
+ }
+
+ bio_add_page(ctx->bio, page, plen, poff);
+done:
+ /*
+ * Move the caller beyond our range so that it keeps making progress.
+ * For that we have to include any leading non-uptodate ranges, but
+ * we can skip trailing ones as they will be handled in the next
+ * iteration.
+ */
+ return pos - orig_pos + plen;
+}
+
+int
+iomap_readpage(struct page *page, const struct iomap_ops *ops)
+{
+ struct iomap_readpage_ctx ctx = { .cur_page = page };
+ struct inode *inode = page->mapping->host;
+ unsigned poff;
+ loff_t ret;
+
+ for (poff = 0; poff < PAGE_SIZE; poff += ret) {
+ ret = iomap_apply(inode, page_offset(page) + poff,
+ PAGE_SIZE - poff, 0, ops, &ctx,
+ iomap_readpage_actor);
+ if (ret <= 0) {
+ WARN_ON_ONCE(ret == 0);
+ SetPageError(page);
+ break;
+ }
+ }
+
+ if (ctx.bio) {
+ submit_bio(ctx.bio);
+ WARN_ON_ONCE(!ctx.cur_page_in_bio);
+ } else {
+ WARN_ON_ONCE(ctx.cur_page_in_bio);
+ unlock_page(page);
+ }
+
+ /*
+ * Just like mpage_readpages and block_read_full_page we always
+ * return 0 and just mark the page as PageError on errors. This
+ * should be cleaned up all through the stack eventually.
+ */
+ return 0;
+}
+EXPORT_SYMBOL_GPL(iomap_readpage);
+
+static struct page *
+iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos,
+ loff_t length, loff_t *done)
+{
+ while (!list_empty(pages)) {
+ struct page *page = lru_to_page(pages);
+
+ if (page_offset(page) >= (u64)pos + length)
+ break;
+
+ list_del(&page->lru);
+ if (!add_to_page_cache_lru(page, inode->i_mapping, page->index,
+ GFP_NOFS))
+ return page;
+
+ /*
+ * If we already have a page in the page cache at index we are
+ * done. Upper layers don't care if it is uptodate after the
+ * readpages call itself as every page gets checked again once
+ * actually needed.
+ */
+ *done += PAGE_SIZE;
+ put_page(page);
+ }
+
+ return NULL;
+}
+
+static loff_t
+iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length,
+ void *data, struct iomap *iomap)
+{
+ struct iomap_readpage_ctx *ctx = data;
+ loff_t done, ret;
+
+ for (done = 0; done < length; done += ret) {
+ if (ctx->cur_page && offset_in_page(pos + done) == 0) {
+ if (!ctx->cur_page_in_bio)
+ unlock_page(ctx->cur_page);
+ put_page(ctx->cur_page);
+ ctx->cur_page = NULL;
+ }
+ if (!ctx->cur_page) {
+ ctx->cur_page = iomap_next_page(inode, ctx->pages,
+ pos, length, &done);
+ if (!ctx->cur_page)
+ break;
+ ctx->cur_page_in_bio = false;
+ }
+ ret = iomap_readpage_actor(inode, pos + done, length - done,
+ ctx, iomap);
+ }
+
+ return done;
+}
+
+int
+iomap_readpages(struct address_space *mapping, struct list_head *pages,
+ unsigned nr_pages, const struct iomap_ops *ops)
+{
+ struct iomap_readpage_ctx ctx = {
+ .pages = pages,
+ .is_readahead = true,
+ };
+ loff_t pos = page_offset(list_entry(pages->prev, struct page, lru));
+ loff_t last = page_offset(list_entry(pages->next, struct page, lru));
+ loff_t length = last - pos + PAGE_SIZE, ret = 0;
+
+ while (length > 0) {
+ ret = iomap_apply(mapping->host, pos, length, 0, ops,
+ &ctx, iomap_readpages_actor);
+ if (ret <= 0) {
+ WARN_ON_ONCE(ret == 0);
+ goto done;
+ }
+ pos += ret;
+ length -= ret;
+ }
+ ret = 0;
+done:
+ if (ctx.bio)
+ submit_bio(ctx.bio);
+ if (ctx.cur_page) {
+ if (!ctx.cur_page_in_bio)
+ unlock_page(ctx.cur_page);
+ put_page(ctx.cur_page);
+ }
+
+ /*
+ * Check that we didn't lose a page due to the arcance calling
+ * conventions..
+ */
+ WARN_ON_ONCE(!ret && !list_empty(ctx.pages));
+ return ret;
+}
+EXPORT_SYMBOL_GPL(iomap_readpages);
+
+/*
+ * iomap_is_partially_uptodate checks whether blocks within a page are
+ * uptodate or not.
+ *
+ * Returns true if all blocks which correspond to a file portion
+ * we want to read within the page are uptodate.
+ */
+int
+iomap_is_partially_uptodate(struct page *page, unsigned long from,
+ unsigned long count)
+{
+ struct iomap_page *iop = to_iomap_page(page);
+ struct inode *inode = page->mapping->host;
+ unsigned len, first, last;
+ unsigned i;
+
+ /* Limit range to one page */
+ len = min_t(unsigned, PAGE_SIZE - from, count);
+
+ /* First and last blocks in range within page */
+ first = from >> inode->i_blkbits;
+ last = (from + len - 1) >> inode->i_blkbits;
+
+ if (iop) {
+ for (i = first; i <= last; i++)
+ if (!test_bit(i, iop->uptodate))
+ return 0;
+ return 1;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(iomap_is_partially_uptodate);
+
+int
+iomap_releasepage(struct page *page, gfp_t gfp_mask)
+{
+ /*
+ * mm accommodates an old ext3 case where clean pages might not have had
+ * the dirty bit cleared. Thus, it can send actual dirty pages to
+ * ->releasepage() via shrink_active_list(), skip those here.
+ */
+ if (PageDirty(page) || PageWriteback(page))
+ return 0;
+ iomap_page_release(page);
+ return 1;
+}
+EXPORT_SYMBOL_GPL(iomap_releasepage);
+
+void
+iomap_invalidatepage(struct page *page, unsigned int offset, unsigned int len)
+{
+ /*
+ * If we are invalidating the entire page, clear the dirty state from it
+ * and release it to avoid unnecessary buildup of the LRU.
+ */
+ if (offset == 0 && len == PAGE_SIZE) {
+ WARN_ON_ONCE(PageWriteback(page));
+ cancel_dirty_page(page);
+ iomap_page_release(page);
+ }
+}
+EXPORT_SYMBOL_GPL(iomap_invalidatepage);
+
+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_read_page_sync(struct inode *inode, loff_t block_start, struct page *page,
+ unsigned poff, unsigned plen, unsigned from, unsigned to,
+ struct iomap *iomap)
+{
+ struct bio_vec bvec;
+ struct bio bio;
+
+ if (iomap->type != IOMAP_MAPPED || block_start >= i_size_read(inode)) {
+ zero_user_segments(page, poff, from, to, poff + plen);
+ iomap_set_range_uptodate(page, poff, plen);
+ return 0;
+ }
+
+ bio_init(&bio, &bvec, 1);
+ bio.bi_opf = REQ_OP_READ;
+ bio.bi_iter.bi_sector = iomap_sector(iomap, block_start);
+ bio_set_dev(&bio, iomap->bdev);
+ __bio_add_page(&bio, page, plen, poff);
+ return submit_bio_wait(&bio);
+}
+
+static int
+__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len,
+ struct page *page, struct iomap *iomap)
+{
+ struct iomap_page *iop = iomap_page_create(inode, page);
+ loff_t block_size = i_blocksize(inode);
+ loff_t block_start = pos & ~(block_size - 1);
+ loff_t block_end = (pos + len + block_size - 1) & ~(block_size - 1);
+ unsigned from = offset_in_page(pos), to = from + len, poff, plen;
+ int status = 0;
+
+ if (PageUptodate(page))
+ return 0;
+
+ do {
+ iomap_adjust_read_range(inode, iop, &block_start,
+ block_end - block_start, &poff, &plen);
+ if (plen == 0)
+ break;
+
+ if ((from > poff && from < poff + plen) ||
+ (to > poff && to < poff + plen)) {
+ status = iomap_read_page_sync(inode, block_start, page,
+ poff, plen, from, to, iomap);
+ if (status)
+ break;
+ }
+
+ } while ((block_start += plen) < block_end);
+
+ return status;
+}
+
+static int
+iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, struct iomap *iomap)
+{
+ const struct iomap_page_ops *page_ops = iomap->page_ops;
+ 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;
+
+ if (page_ops && page_ops->page_prepare) {
+ status = page_ops->page_prepare(inode, pos, len, iomap);
+ if (status)
+ return status;
+ }
+
+ page = grab_cache_page_write_begin(inode->i_mapping, index, flags);
+ if (!page) {
+ status = -ENOMEM;
+ goto out_no_page;
+ }
+
+ if (iomap->type == IOMAP_INLINE)
+ iomap_read_inline_data(inode, page, iomap);
+ else if (iomap->flags & IOMAP_F_BUFFER_HEAD)
+ status = __block_write_begin_int(page, pos, len, NULL, iomap);
+ else
+ status = __iomap_write_begin(inode, pos, len, page, iomap);
+
+ if (unlikely(status))
+ goto out_unlock;
+
+ *pagep = page;
+ return 0;
+
+out_unlock:
+ unlock_page(page);
+ put_page(page);
+ iomap_write_failed(inode, pos, len);
+
+out_no_page:
+ if (page_ops && page_ops->page_done)
+ page_ops->page_done(inode, pos, 0, NULL, iomap);
+ return status;
+}
+
+int
+iomap_set_page_dirty(struct page *page)
+{
+ struct address_space *mapping = page_mapping(page);
+ int newly_dirty;
+
+ if (unlikely(!mapping))
+ return !TestSetPageDirty(page);
+
+ /*
+ * Lock out page->mem_cgroup migration to keep PageDirty
+ * synchronized with per-memcg dirty page counters.
+ */
+ lock_page_memcg(page);
+ newly_dirty = !TestSetPageDirty(page);
+ if (newly_dirty)
+ __set_page_dirty(page, mapping, 0);
+ unlock_page_memcg(page);
+
+ if (newly_dirty)
+ __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+ return newly_dirty;
+}
+EXPORT_SYMBOL_GPL(iomap_set_page_dirty);
+
+static int
+__iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
+ unsigned copied, struct page *page, struct iomap *iomap)
+{
+ flush_dcache_page(page);
+
+ /*
+ * The blocks that were entirely written will now be uptodate, so we
+ * don't have to worry about a readpage reading them and overwriting a
+ * partial write. However if we have encountered a short write and only
+ * partially written into a block, it will not be marked uptodate, so a
+ * readpage might come in and destroy our partial write.
+ *
+ * Do the simplest thing, and just treat any short write to a non
+ * uptodate page as a zero-length write, and force the caller to redo
+ * the whole thing.
+ */
+ if (unlikely(copied < len && !PageUptodate(page)))
+ return 0;
+ iomap_set_range_uptodate(page, offset_in_page(pos), len);
+ iomap_set_page_dirty(page);
+ return copied;
+}
+
+static int
+iomap_write_end_inline(struct inode *inode, struct page *page,
+ struct iomap *iomap, loff_t pos, unsigned copied)
+{
+ void *addr;
+
+ WARN_ON_ONCE(!PageUptodate(page));
+ BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data));
+
+ addr = kmap_atomic(page);
+ memcpy(iomap->inline_data + pos, addr + pos, copied);
+ kunmap_atomic(addr);
+
+ mark_inode_dirty(inode);
+ return copied;
+}
+
+static int
+iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
+ unsigned copied, struct page *page, struct iomap *iomap)
+{
+ const struct iomap_page_ops *page_ops = iomap->page_ops;
+ loff_t old_size = inode->i_size;
+ int ret;
+
+ if (iomap->type == IOMAP_INLINE) {
+ ret = iomap_write_end_inline(inode, page, iomap, pos, copied);
+ } else if (iomap->flags & IOMAP_F_BUFFER_HEAD) {
+ ret = block_write_end(NULL, inode->i_mapping, pos, len, copied,
+ page, NULL);
+ } else {
+ ret = __iomap_write_end(inode, pos, len, copied, page, iomap);
+ }
+
+ /*
+ * Update the in-memory inode size after copying the data into the page
+ * cache. It's up to the file system to write the updated size to disk,
+ * preferably after I/O completion so that no stale data is exposed.
+ */
+ if (pos + ret > old_size) {
+ i_size_write(inode, pos + ret);
+ iomap->flags |= IOMAP_F_SIZE_CHANGED;
+ }
+ unlock_page(page);
+
+ if (old_size < pos)
+ pagecache_isize_extended(inode, old_size, pos);
+ if (page_ops && page_ops->page_done)
+ page_ops->page_done(inode, pos, ret, page, iomap);
+ put_page(page);
+
+ 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 = offset_in_page(pos);
+ 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,
+ iomap);
+ 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 = offset_in_page(pos);
+ 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, iomap);
+ 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, iomap);
+}
+
+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 = offset_in_page(pos);
+ 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;
+
+ if (iomap->flags & IOMAP_F_BUFFER_HEAD) {
+ ret = __block_write_begin_int(page, pos, length, NULL, iomap);
+ if (ret)
+ return ret;
+ block_commit_write(page, 0, length);
+ } else {
+ WARN_ON_ONCE(!PageUptodate(page));
+ iomap_page_create(inode, page);
+ set_page_dirty(page);
+ }
+
+ return length;
+}
+
+vm_fault_t 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 = offset_in_page(size);
+ 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;
+ }
+
+ 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);
^ permalink raw reply related [flat|nested] 23+ messages in thread