lkml.org 
[lkml]   [2016]   [Aug]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 3/7] dax: remove buffer_size_valid()
Date
Now that all our supported filesystems (ext2, ext4 and XFS) all properly
set 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@linux.intel.com>
---
fs/dax.c | 22 +---------------------
1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index 993dc6f..8030f93 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -121,19 +121,6 @@ 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)
{
@@ -175,8 +162,6 @@ 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;
/*
@@ -1010,12 +995,7 @@ 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;
}
--
2.9.0
\
 
 \ /
  Last update: 2016-09-17 09:57    [W:0.021 / U:3.256 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site