From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Move the buffered read 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@xxxxxxxxxx>
---
fs/iomap.c | 335 ---------------------------------------------------
fs/iomap/Makefile | 1
fs/iomap/read.c | 349 +++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 350 insertions(+), 335 deletions(-)
create mode 100644 fs/iomap/read.c
diff --git a/fs/iomap.c b/fs/iomap.c
index 72db8a6c0292..f339fb5fde43 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -135,66 +135,6 @@ iomap_page_release(struct page *page)
kfree(iop);
}
-/*
- * Calculate the range inside the page that we actually need to read.
- */
-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;
-}
-
void
iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len)
{
@@ -218,280 +158,6 @@ iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len)
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;
-};
-
-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 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) {
- if (__bio_try_merge_page(ctx->bio, page, plen, poff, true))
- goto done;
- is_contig = true;
- }
-
- /*
- * 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)) {
- 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.
@@ -623,4 +289,3 @@ iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
return iomap_zero_range(inode, pos, blocksize - off, did_zero, ops);
}
EXPORT_SYMBOL_GPL(iomap_truncate_page);
-
diff --git a/fs/iomap/Makefile b/fs/iomap/Makefile
index c6859e19a9ef..651bd66bfce7 100644
--- a/fs/iomap/Makefile
+++ b/fs/iomap/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_FS_IOMAP) += iomap.o
iomap-y += \
direct-io.o \
fiemap.o \
+ read.o \
seek.o \
write.o
diff --git a/fs/iomap/read.c b/fs/iomap/read.c
new file mode 100644
index 000000000000..237516d0af8b
--- /dev/null
+++ b/fs/iomap/read.c
@@ -0,0 +1,349 @@
+// 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/bio.h>
+#include <linux/pagemap.h>
+#include <linux/blkdev.h>
+
+#include "internal.h"
+#include "iomap_internal.h"
+
+/*
+ * Calculate the range inside the page that we actually need to read.
+ */
+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_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;
+};
+
+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 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) {
+ if (__bio_try_merge_page(ctx->bio, page, plen, poff, true))
+ goto done;
+ is_contig = true;
+ }
+
+ /*
+ * 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)) {
+ 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);
