Commit ff5df9b8 authored May 30, 2014 by Filipe Manana Committed by Chris Mason Jun 09, 2014

Btrfs: ioctl, don't re-lock extent range when not necessary



In ioctl.c:lock_extent_range(), after locking our target range, the
ordered extent that btrfs_lookup_first_ordered_extent() returns us
may not overlap our target range at all. In this case we would just
unlock our target range, wait for any new ordered extents that overlap
the range to complete, lock again the range and repeat all these steps
until we don't get any ordered extent and the delalloc flag isn't set
in the io tree for our target range.

Therefore just stop if we get an ordered extent that doesn't overlap
our target range and the dealalloc flag isn't set for the range in
the inode's io tree.

Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>

parent 2c463823

fs/btrfs/ioctl.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -2700,10 +2700,15 @@ static inline void lock_extent_range(struct inode *inode, u64 off, u64 len)
		lock_extent(&BTRFS_I(inode)->io_tree, off, off + len - 1);
		ordered = btrfs_lookup_first_ordered_extent(inode,
		off + len - 1);
		if (!ordered &&
		if ((!ordered \|\|
		ordered->file_offset + ordered->len <= off \|\|
		ordered->file_offset >= off + len) &&
		!test_range_bit(&BTRFS_I(inode)->io_tree, off,
		off + len - 1, EXTENT_DELALLOC, 0, NULL))
		off + len - 1, EXTENT_DELALLOC, 0, NULL)) {
		if (ordered)
		btrfs_put_ordered_extent(ordered);
		break;
		}
		unlock_extent(&BTRFS_I(inode)->io_tree, off, off + len - 1);
		if (ordered)
		btrfs_put_ordered_extent(ordered);

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