(2011/10/14 2:11), Josef Bacik wrote:
> Recently I changed the xattr stuff to unconditionally set the xattr first in
> case the xattr didn't exist yet. This has introduced a regression when setting
> an xattr that already exists with a large value. If we find the key we are
> looking for split_leaf will assume that we're extending that item. The problem
> is the size we pass down to btrfs_search_slot includes the size of the item
> already, so if we have the largest xattr we can possibly have plus the size of
> the xattr item plus the xattr item that btrfs_search_slot we'd overflow the
> leaf. Thankfully this is not what we're doing, but split_leaf doesn't know this
> so it just returns EOVERFLOW. So in the xattr code we need to check and see if
> we got back EOVERFLOW and treat it like EEXIST since that's really what
> happened. Thanks,
>
> Signed-off-by: Josef Bacik <josef@xxxxxxxxxx>
> ---
> fs/btrfs/xattr.c | 13 ++++++++++++-
> 1 files changed, 12 insertions(+), 1 deletions(-)
>
> diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
> index 69565e5..5bd7877 100644
> --- a/fs/btrfs/xattr.c
> +++ b/fs/btrfs/xattr.c
> @@ -127,7 +127,18 @@ static int do_setxattr(struct btrfs_trans_handle *trans,
> again:
> ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
> name, name_len, value, size);
> - if (ret == -EEXIST) {
> + /*
> + * If we're setting an xattr to a new value but the new value is say
> + * exactly BTRFS_MAX_XATTR_SIZE, we could end up with EOVERFLOW getting
> + * back from split_leaf. This is because it thinks we'll be extending
> + * the existing item size, but we're asking for enough space to add the
> + * item itself. So if we get EOVERFLOW just set ret to EEXIST and let
> + * the rest of the function figure it out.
> + */
> + if (ret == -EOVERFLOW)
> + ret = -EEXIST;
> +
> + if (ret == -EEXIST || ret == -EOVERFLOW) {
Why tested again EOVERFLOW?
Thanks,
Tsutomu
> if (flags & XATTR_CREATE)
> goto out;
> /*
--
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