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Message-Id: <20180530100208.31490-2-hch@lst.de>
Date: Wed, 30 May 2018 12:02:06 +0200
From: Christoph Hellwig <hch@....de>
To: linux-xfs@...r.kernel.org
Cc: Andreas Gruenbacher <agruenba@...hat.com>,
linux-fsdevel@...r.kernel.org, linux-ext4@...r.kernel.org
Subject: [PATCH 1/3] fs: move page_cache_seek_hole_data to iomap.c
This function is only used by the iomap code, depends on being called
from it, and will soon stop poking into buffer head internals.
Signed-off-by: Christoph Hellwig <hch@....de>
---
fs/buffer.c | 114 -----------------------------------
fs/iomap.c | 116 ++++++++++++++++++++++++++++++++++++
include/linux/buffer_head.h | 2 -
3 files changed, 116 insertions(+), 116 deletions(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index 249b83fafe48..cabc045f483d 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3427,120 +3427,6 @@ int bh_submit_read(struct buffer_head *bh)
}
EXPORT_SYMBOL(bh_submit_read);
-/*
- * Seek for SEEK_DATA / SEEK_HOLE within @page, starting at @lastoff.
- *
- * Returns the offset within the file on success, and -ENOENT otherwise.
- */
-static loff_t
-page_seek_hole_data(struct page *page, loff_t lastoff, int whence)
-{
- loff_t offset = page_offset(page);
- struct buffer_head *bh, *head;
- bool seek_data = whence == SEEK_DATA;
-
- if (lastoff < offset)
- lastoff = offset;
-
- bh = head = page_buffers(page);
- do {
- offset += bh->b_size;
- if (lastoff >= offset)
- continue;
-
- /*
- * Unwritten extents that have data in the page cache covering
- * them can be identified by the BH_Unwritten state flag.
- * Pages with multiple buffers might have a mix of holes, data
- * and unwritten extents - any buffer with valid data in it
- * should have BH_Uptodate flag set on it.
- */
-
- if ((buffer_unwritten(bh) || buffer_uptodate(bh)) == seek_data)
- return lastoff;
-
- lastoff = offset;
- } while ((bh = bh->b_this_page) != head);
- return -ENOENT;
-}
-
-/*
- * Seek for SEEK_DATA / SEEK_HOLE in the page cache.
- *
- * Within unwritten extents, the page cache determines which parts are holes
- * and which are data: unwritten and uptodate buffer heads count as data;
- * everything else counts as a hole.
- *
- * Returns the resulting offset on successs, and -ENOENT otherwise.
- */
-loff_t
-page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length,
- int whence)
-{
- pgoff_t index = offset >> PAGE_SHIFT;
- pgoff_t end = DIV_ROUND_UP(offset + length, PAGE_SIZE);
- loff_t lastoff = offset;
- struct pagevec pvec;
-
- if (length <= 0)
- return -ENOENT;
-
- pagevec_init(&pvec);
-
- do {
- unsigned nr_pages, i;
-
- nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping, &index,
- end - 1);
- if (nr_pages == 0)
- break;
-
- for (i = 0; i < nr_pages; i++) {
- struct page *page = pvec.pages[i];
-
- /*
- * At this point, the page may be truncated or
- * invalidated (changing page->mapping to NULL), or
- * even swizzled back from swapper_space to tmpfs file
- * mapping. However, page->index will not change
- * because we have a reference on the page.
- *
- * If current page offset is beyond where we've ended,
- * we've found a hole.
- */
- if (whence == SEEK_HOLE &&
- lastoff < page_offset(page))
- goto check_range;
-
- lock_page(page);
- if (likely(page->mapping == inode->i_mapping) &&
- page_has_buffers(page)) {
- lastoff = page_seek_hole_data(page, lastoff, whence);
- if (lastoff >= 0) {
- unlock_page(page);
- goto check_range;
- }
- }
- unlock_page(page);
- lastoff = page_offset(page) + PAGE_SIZE;
- }
- pagevec_release(&pvec);
- } while (index < end);
-
- /* When no page at lastoff and we are not done, we found a hole. */
- if (whence != SEEK_HOLE)
- goto not_found;
-
-check_range:
- if (lastoff < offset + length)
- goto out;
-not_found:
- lastoff = -ENOENT;
-out:
- pagevec_release(&pvec);
- return lastoff;
-}
-
void __init buffer_init(void)
{
unsigned long nrpages;
diff --git a/fs/iomap.c b/fs/iomap.c
index 5e5a266e3325..c2d4fd551fed 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -21,6 +21,7 @@
#include <linux/mm_inline.h>
#include <linux/swap.h>
#include <linux/pagemap.h>
+#include <linux/pagevec.h>
#include <linux/file.h>
#include <linux/uio.h>
#include <linux/backing-dev.h>
@@ -793,6 +794,121 @@ int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi,
}
EXPORT_SYMBOL_GPL(iomap_fiemap);
+/*
+ * Seek for SEEK_DATA / SEEK_HOLE within @page, starting at @lastoff.
+ *
+ * Returns the offset within the file on success, and -ENOENT otherwise.
+ */
+static loff_t
+page_seek_hole_data(struct page *page, loff_t lastoff, int whence)
+{
+ loff_t offset = page_offset(page);
+ struct buffer_head *bh, *head;
+ bool seek_data = whence == SEEK_DATA;
+
+ if (lastoff < offset)
+ lastoff = offset;
+
+ bh = head = page_buffers(page);
+ do {
+ offset += bh->b_size;
+ if (lastoff >= offset)
+ continue;
+
+ /*
+ * Unwritten extents that have data in the page cache covering
+ * them can be identified by the BH_Unwritten state flag.
+ * Pages with multiple buffers might have a mix of holes, data
+ * and unwritten extents - any buffer with valid data in it
+ * should have BH_Uptodate flag set on it.
+ */
+
+ if ((buffer_unwritten(bh) || buffer_uptodate(bh)) == seek_data)
+ return lastoff;
+
+ lastoff = offset;
+ } while ((bh = bh->b_this_page) != head);
+ return -ENOENT;
+}
+
+/*
+ * Seek for SEEK_DATA / SEEK_HOLE in the page cache.
+ *
+ * Within unwritten extents, the page cache determines which parts are holes
+ * and which are data: unwritten and uptodate buffer heads count as data;
+ * everything else counts as a hole.
+ *
+ * Returns the resulting offset on successs, and -ENOENT otherwise.
+ */
+static loff_t
+page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length,
+ int whence)
+{
+ pgoff_t index = offset >> PAGE_SHIFT;
+ pgoff_t end = DIV_ROUND_UP(offset + length, PAGE_SIZE);
+ loff_t lastoff = offset;
+ struct pagevec pvec;
+
+ if (length <= 0)
+ return -ENOENT;
+
+ pagevec_init(&pvec);
+
+ do {
+ unsigned nr_pages, i;
+
+ nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping, &index,
+ end - 1);
+ if (nr_pages == 0)
+ break;
+
+ for (i = 0; i < nr_pages; i++) {
+ struct page *page = pvec.pages[i];
+
+ /*
+ * At this point, the page may be truncated or
+ * invalidated (changing page->mapping to NULL), or
+ * even swizzled back from swapper_space to tmpfs file
+ * mapping. However, page->index will not change
+ * because we have a reference on the page.
+ *
+ * If current page offset is beyond where we've ended,
+ * we've found a hole.
+ */
+ if (whence == SEEK_HOLE &&
+ lastoff < page_offset(page))
+ goto check_range;
+
+ lock_page(page);
+ if (likely(page->mapping == inode->i_mapping) &&
+ page_has_buffers(page)) {
+ lastoff = page_seek_hole_data(page, lastoff, whence);
+ if (lastoff >= 0) {
+ unlock_page(page);
+ goto check_range;
+ }
+ }
+ unlock_page(page);
+ lastoff = page_offset(page) + PAGE_SIZE;
+ }
+ pagevec_release(&pvec);
+ } while (index < end);
+
+ /* When no page at lastoff and we are not done, we found a hole. */
+ if (whence != SEEK_HOLE)
+ goto not_found;
+
+check_range:
+ if (lastoff < offset + length)
+ goto out;
+not_found:
+ lastoff = -ENOENT;
+out:
+ pagevec_release(&pvec);
+ return lastoff;
+}
+
+
static loff_t
iomap_seek_hole_actor(struct inode *inode, loff_t offset, loff_t length,
void *data, struct iomap *iomap)
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 894e5d125de6..96225a77c112 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -205,8 +205,6 @@ void write_boundary_block(struct block_device *bdev,
sector_t bblock, unsigned blocksize);
int bh_uptodate_or_lock(struct buffer_head *bh);
int bh_submit_read(struct buffer_head *bh);
-loff_t page_cache_seek_hole_data(struct inode *inode, loff_t offset,
- loff_t length, int whence);
extern int buffer_heads_over_limit;
--
2.17.0
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