diff options
author | Matthew Wilcox <mawilcox@microsoft.com> | 2016-12-14 15:08:49 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-12-14 16:04:10 -0800 |
commit | 148deab223b23734069abcacb5c7118b0e7deadc (patch) | |
tree | 56aae9c91802e9262312f7fcbb3571eb9c8ec0e9 /fs/btrfs/tests | |
parent | b35df27a39f40e39fabf1b1e9569c7b24e1add6a (diff) | |
download | linux-stable-148deab223b23734069abcacb5c7118b0e7deadc.tar.gz linux-stable-148deab223b23734069abcacb5c7118b0e7deadc.tar.bz2 linux-stable-148deab223b23734069abcacb5c7118b0e7deadc.zip |
radix-tree: improve multiorder iterators
This fixes several interlinked problems with the iterators in the
presence of multiorder entries.
1. radix_tree_iter_next() would only advance by one slot, which would
result in the iterators returning the same entry more than once if
there were sibling entries.
2. radix_tree_next_slot() could return an internal pointer instead of
a user pointer if a tagged multiorder entry was immediately followed by
an entry of lower order.
3. radix_tree_next_slot() expanded to a lot more code than it used to
when multiorder support was compiled in. And I wasn't comfortable with
entry_to_node() being in a header file.
Fixing radix_tree_iter_next() for the presence of sibling entries
necessarily involves examining the contents of the radix tree, so we now
need to pass 'slot' to radix_tree_iter_next(), and we need to change the
calling convention so it is called *before* dropping the lock which
protects the tree. Also rename it to radix_tree_iter_resume(), as some
people thought it was necessary to call radix_tree_iter_next() each time
around the loop.
radix_tree_next_slot() becomes closer to how it looked before multiorder
support was introduced. It only checks to see if the next entry in the
chunk is a sibling entry or a pointer to a node; this should be rare
enough that handling this case out of line is not a performance impact
(and such impact is amortised by the fact that the entry we just
processed was a multiorder entry). Also, radix_tree_next_slot() used to
force a new chunk lookup for untagged entries, which is more expensive
than the out of line sibling entry skipping.
Link: http://lkml.kernel.org/r/1480369871-5271-55-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/btrfs/tests')
-rw-r--r-- | fs/btrfs/tests/btrfs-tests.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/btrfs/tests/btrfs-tests.c b/fs/btrfs/tests/btrfs-tests.c index 73076a0ea6a9..00ee006a8aa2 100644 --- a/fs/btrfs/tests/btrfs-tests.c +++ b/fs/btrfs/tests/btrfs-tests.c @@ -162,7 +162,7 @@ void btrfs_free_dummy_fs_info(struct btrfs_fs_info *fs_info) slot = radix_tree_iter_retry(&iter); continue; } - slot = radix_tree_iter_next(&iter); + slot = radix_tree_iter_resume(slot, &iter); spin_unlock(&fs_info->buffer_lock); free_extent_buffer_stale(eb); spin_lock(&fs_info->buffer_lock); |