On Sun, Feb 23, 2020 at 4:07 AM Allison Collins
<allison.henderson@xxxxxxxxxx> wrote:
>
> From: Allison Henderson <allison.henderson@xxxxxxxxxx>
>
> This patch adds a new functions to check for the existence of an attribute.
> Subroutines are also added to handle the cases of leaf blocks, nodes or shortform.
> Common code that appears in existing attr add and remove functions have been
> factored out to help reduce the appearance of duplicated code. We will need these
> routines later for delayed attributes since delayed operations cannot return error
> codes.
>
> Signed-off-by: Allison Collins <allison.henderson@xxxxxxxxxx>
> ---
> fs/xfs/libxfs/xfs_attr.c | 171 ++++++++++++++++++++++++++++--------------
> fs/xfs/libxfs/xfs_attr.h | 1 +
> fs/xfs/libxfs/xfs_attr_leaf.c | 111 +++++++++++++++++----------
> fs/xfs/libxfs/xfs_attr_leaf.h | 3 +
> 4 files changed, 188 insertions(+), 98 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 9acdb23..2255060 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -46,6 +46,7 @@ STATIC int xfs_attr_shortform_addname(xfs_da_args_t *args);
> STATIC int xfs_attr_leaf_get(xfs_da_args_t *args);
> STATIC int xfs_attr_leaf_addname(xfs_da_args_t *args);
> STATIC int xfs_attr_leaf_removename(xfs_da_args_t *args);
> +STATIC int xfs_attr_leaf_hasname(struct xfs_da_args *args, struct xfs_buf **bp);
>
> /*
> * Internal routines when attribute list is more than one block.
> @@ -53,6 +54,8 @@ STATIC int xfs_attr_leaf_removename(xfs_da_args_t *args);
> STATIC int xfs_attr_node_get(xfs_da_args_t *args);
> STATIC int xfs_attr_node_addname(xfs_da_args_t *args);
> STATIC int xfs_attr_node_removename(xfs_da_args_t *args);
> +STATIC int xfs_attr_node_hasname(xfs_da_args_t *args,
> + struct xfs_da_state **state);
> STATIC int xfs_attr_fillstate(xfs_da_state_t *state);
> STATIC int xfs_attr_refillstate(xfs_da_state_t *state);
>
> @@ -310,6 +313,37 @@ xfs_attr_set_args(
> }
>
> /*
> + * Return EEXIST if attr is found, or ENOATTR if not
This is a very silly return value for a function named has_attr in my taste.
I realize you inherited this interface from xfs_attr3_leaf_lookup_int(), but
IMO this change looks like a very good opportunity to change that internal
API:
xfs_has_attr?
0: NO
1: YES (or stay with the syscall standard of -ENOATTR)
<0: error
> + */
> +int
> +xfs_has_attr(
> + struct xfs_da_args *args)
> +{
> + struct xfs_inode *dp = args->dp;
> + struct xfs_buf *bp = NULL;
> + int error;
> +
> + if (!xfs_inode_hasattr(dp))
> + return -ENOATTR;
> +
> + if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
> + ASSERT(dp->i_afp->if_flags & XFS_IFINLINE);
> + return xfs_attr_sf_findname(args, NULL, NULL);
> + }
> +
> + if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
> + error = xfs_attr_leaf_hasname(args, &bp);
> +
> + if (bp)
> + xfs_trans_brelse(args->trans, bp);
> +
> + return error;
> + }
> +
> + return xfs_attr_node_hasname(args, NULL);
> +}
> +
> +/*
> * Remove the attribute specified in @args.
> */
> int
> @@ -583,26 +617,20 @@ STATIC int
> xfs_attr_leaf_addname(
> struct xfs_da_args *args)
> {
> - struct xfs_inode *dp;
> struct xfs_buf *bp;
> int retval, error, forkoff;
> + struct xfs_inode *dp = args->dp;
>
> trace_xfs_attr_leaf_addname(args);
>
> /*
> - * Read the (only) block in the attribute list in.
> - */
> - dp = args->dp;
> - args->blkno = 0;
> - error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno, &bp);
> - if (error)
> - return error;
> -
> - /*
> * Look up the given attribute in the leaf block. Figure out if
> * the given flags produce an error or call for an atomic rename.
> */
> - retval = xfs_attr3_leaf_lookup_int(bp, args);
> + retval = xfs_attr_leaf_hasname(args, &bp);
> + if (retval != -ENOATTR && retval != -EEXIST)
> + return retval;
> +
> if ((args->name.type & ATTR_REPLACE) && (retval == -ENOATTR)) {
Example of how sane code (in my taste) would look like:
retval = xfs_attr_leaf_hasname(args, &bp);
if (retval < 0)
return retval;
if ((args->name.type & ATTR_REPLACE) && !retval) {
xfs_trans_brelse(args->trans, bp);
return -ENOATTR;
} else if (retval) {
if (args->flags & ATTR_CREATE) { /* pure create op */
xfs_trans_brelse(args->trans, bp);
return -EEXIST;
}
Thanks,
Amir.
