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Date: Mon, 15 Aug 2016 13:09:14 -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>, Dan Williams <dan.j.williams@...el.com>, Dave Chinner <david@...morbit.com>, Jan Kara <jack@...e.com>, linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org, linux-mm@...ck.org, linux-nvdimm@...ts.01.org Subject: [PATCH 3/7] dax: remove buffer_size_valid() 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@...ux.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 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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