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Message-Id: <1475874544-24842-4-git-send-email-ross.zwisler@linux.intel.com>
Date: Fri, 7 Oct 2016 15:08:50 -0600
From: Ross Zwisler <ross.zwisler@...ux.intel.com>
To: linux-kernel@...r.kernel.org
Cc: Ross Zwisler <ross.zwisler@...ux.intel.com>,
"Theodore Ts'o" <tytso@....edu>,
Alexander Viro <viro@...iv.linux.org.uk>,
Andreas Dilger <adilger.kernel@...ger.ca>,
Andrew Morton <akpm@...ux-foundation.org>,
Christoph Hellwig <hch@....de>,
Dan Williams <dan.j.williams@...el.com>,
Dave Chinner <david@...morbit.com>, Jan Kara <jack@...e.com>,
Matthew Wilcox <mawilcox@...rosoft.com>,
linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-mm@...ck.org, linux-nvdimm@...ts.01.org,
linux-xfs@...r.kernel.org
Subject: [PATCH v5 03/17] dax: remove buffer_size_valid()
Now that ext4 properly sets bh.b_size when we call get_block() for a hole,
rely on that value and remove the buffer_size_valid() sanity check.
Signed-off-by: Ross Zwisler <ross.zwisler@...ux.intel.com>
Reviewed-by: Jan Kara <jack@...e.cz>
Reviewed-by: Christoph Hellwig <hch@....de>
---
fs/dax.c | 22 +---------------------
1 file changed, 1 insertion(+), 21 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index cc025f8..9b9be8a 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -123,19 +123,6 @@ static bool buffer_written(struct buffer_head *bh)
return buffer_mapped(bh) && !buffer_unwritten(bh);
}
-/*
- * When ext4 encounters a hole, it returns without modifying the buffer_head
- * which means that we can't trust b_size. To cope with this, we set b_state
- * to 0 before calling get_block and, if any bit is set, we know we can trust
- * b_size. Unfortunate, really, since ext4 knows precisely how long a hole is
- * and would save us time calling get_block repeatedly.
- */
-static bool buffer_size_valid(struct buffer_head *bh)
-{
- return bh->b_state != 0;
-}
-
-
static sector_t to_sector(const struct buffer_head *bh,
const struct inode *inode)
{
@@ -177,8 +164,6 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
rc = get_block(inode, block, bh, rw == WRITE);
if (rc)
break;
- if (!buffer_size_valid(bh))
- bh->b_size = 1 << blkbits;
bh_max = pos - first + bh->b_size;
bdev = bh->b_bdev;
/*
@@ -1012,12 +997,7 @@ int dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
bdev = bh.b_bdev;
- /*
- * If the filesystem isn't willing to tell us the length of a hole,
- * just fall back to PTEs. Calling get_block 512 times in a loop
- * would be silly.
- */
- if (!buffer_size_valid(&bh) || bh.b_size < PMD_SIZE) {
+ if (bh.b_size < PMD_SIZE) {
dax_pmd_dbg(&bh, address, "allocated block too small");
return VM_FAULT_FALLBACK;
}
--
2.7.4
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