From 32c0a6bcaa1f57e80f67bf3ae2b35d00cea8361a Mon Sep 17 00:00:00 2001
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Date: Sun, 21 Mar 2021 21:03:11 +0000
Subject: [PATCH] btrfs: add and use readahead_batch_length
Implement readahead_batch_length() to determine the number of bytes in
the current batch of readahead pages and use it in btrfs. Also use the
readahead_pos to get the offset.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/extent_io.c | 6 ++----
include/linux/pagemap.h | 9 +++++++++
2 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 18e69e1a5f9cd..a50adbd8808da 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4650,10 +4650,8 @@ void extent_readahead(struct readahead_control *rac)
int nr;
while ((nr = readahead_page_batch(rac, pagepool))) {
- u64 contig_start = page_offset(pagepool[0]);
- u64 contig_end = page_offset(pagepool[nr - 1]) + PAGE_SIZE - 1;
-
- ASSERT(contig_start + nr * PAGE_SIZE - 1 == contig_end);
+ u64 contig_start = readahead_pos(rac);
+ u64 contig_end = contig_start + readahead_batch_length(rac) - 1;
contiguous_readpages(pagepool, nr, contig_start, contig_end,
&em_cached, &bio, &bio_flags, &prev_em_start);
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 8c9947fd62f30..4c1ffe1d5dac9 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -981,6 +981,15 @@ static inline unsigned int readahead_count(struct readahead_control *rac)
return rac->_nr_pages;
}
+/**
+ * readahead_batch_length - The number of bytes in the current batch.
+ * @rac: The readahead request.
+ */
+static inline loff_t readahead_batch_length(struct readahead_control *rac)
+{
+ return rac->_batch_count * PAGE_SIZE;
+}
+
static inline unsigned long dir_pages(struct inode *inode)
{
return (unsigned long)(inode->i_size + PAGE_SIZE - 1) >>
--
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