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    Subject[PATCH 4.4 181/268] Btrfs: fix copy_items() return value when logging an inode
    Date
    4.4-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Filipe Manana <fdmanana@suse.com>

    [ Upstream commit 8434ec46c6e3232cebc25a910363b29f5c617820 ]

    When logging an inode, at tree-log.c:copy_items(), if we call
    btrfs_next_leaf() at the loop which checks for the need to log holes, we
    need to make sure copy_items() returns the value 1 to its caller and
    not 0 (on success). This is because the path the caller passed was
    released and is now different from what is was before, and the caller
    expects a return value of 0 to mean both success and that the path
    has not changed, while a return value of 1 means both success and
    signals the caller that it can not reuse the path, it has to perform
    another tree search.

    Even though this is a case that should not be triggered on normal
    circumstances or very rare at least, its consequences can be very
    unpredictable (especially when replaying a log tree).

    Fixes: 16e7549f045d ("Btrfs: incompatible format change to remove hole extents")
    Signed-off-by: Filipe Manana <fdmanana@suse.com>
    Signed-off-by: David Sterba <dsterba@suse.com>
    Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    fs/btrfs/tree-log.c | 1 +
    1 file changed, 1 insertion(+)

    --- a/fs/btrfs/tree-log.c
    +++ b/fs/btrfs/tree-log.c
    @@ -3835,6 +3835,7 @@ fill_holes:
    ASSERT(ret == 0);
    src = src_path->nodes[0];
    i = 0;
    + need_find_last_extent = true;
    }

    btrfs_item_key_to_cpu(src, &key, i);

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