This is a note to let you know that I've just added the patch titled
Btrfs: do a full search everytime in btrfs_search_old_slot
to the 3.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-do-a-full-search-everytime-in-btrfs_search_old_slot.patch
and it can be found in the queue-3.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From d4b4087c43cc00a196c5be57fac41f41309f1d56 Mon Sep 17 00:00:00 2001
From: Josef Bacik <[email protected]>
Date: Tue, 24 Sep 2013 14:09:34 -0400
Subject: Btrfs: do a full search everytime in btrfs_search_old_slot
From: Josef Bacik <[email protected]>
commit d4b4087c43cc00a196c5be57fac41f41309f1d56 upstream.
While running some snashot aware defrag tests I noticed I was panicing every
once and a while in key_search. This is because of the optimization that says
if we find a key at slot 0 it will be at slot 0 all the way down the rest of the
tree. This isn't the case for btrfs_search_old_slot since it will likely replay
changes to a buffer if something has changed since we took our sequence number.
So short circuit this optimization by setting prev_cmp to -1 every time we call
key_search so we will do our normal binary search. With this patch I am no
longer seeing the panics I was seeing before. Thanks,
Signed-off-by: Josef Bacik <[email protected]>
Signed-off-by: Chris Mason <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/btrfs/ctree.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2758,7 +2758,7 @@ int btrfs_search_old_slot(struct btrfs_r
int level;
int lowest_unlock = 1;
u8 lowest_level = 0;
- int prev_cmp;
+ int prev_cmp = -1;
lowest_level = p->lowest_level;
WARN_ON(p->nodes[0] != NULL);
@@ -2769,7 +2769,6 @@ int btrfs_search_old_slot(struct btrfs_r
}
again:
- prev_cmp = -1;
b = get_old_root(root, time_seq);
level = btrfs_header_level(b);
p->locks[level] = BTRFS_READ_LOCK;
@@ -2787,6 +2786,11 @@ again:
*/
btrfs_unlock_up_safe(p, level + 1);
+ /*
+ * Since we can unwind eb's we want to do a real search every
+ * time.
+ */
+ prev_cmp = -1;
ret = key_search(b, key, level, &prev_cmp, &slot);
if (level != 0) {
Patches currently in stable-queue which might be from [email protected] are
queue-3.12/btrfs-fix-memory-leak-of-chunks-extent-map.patch
queue-3.12/btrfs-fix-lockdep-error-in-async-commit.patch
queue-3.12/btrfs-fix-incorrect-inode-acl-reset.patch
queue-3.12/btrfs-reset-intwrite-on-transaction-abort.patch
queue-3.12/btrfs-do-not-run-snapshot-aware-defragment-on-error.patch
queue-3.12/btrfs-do-a-full-search-everytime-in-btrfs_search_old_slot.patch
queue-3.12/btrfs-take-ordered-root-lock-when-removing-ordered-operations-inode.patch
queue-3.12/btrfs-fix-hole-check-in-log_one_extent.patch
queue-3.12/btrfs-fix-a-crash-when-running-balance-and-defrag-concurrently.patch
queue-3.12/btrfs-stop-using-vfs_read-in-send.patch
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