Re: [PATCH v2 05/18] xfs: Add xfs_has_attr and subroutines

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Fri, Aug 09, 2019 at 02:37:13PM -0700, Allison Collins wrote:
> From: Allison Henderson <allison.henderson@oracle.com>
> 
> 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 appearence of duplicated code.  We will
> need these routines later for delayed attributes since delayed
> operations cannot return error codes.
> 
> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
> Signed-off-by: Allison Collins <allison.henderson@oracle.com>
> ---
>  fs/xfs/libxfs/xfs_attr.c      | 151 +++++++++++++++++++++++++++---------------
>  fs/xfs/libxfs/xfs_attr.h      |   1 +
>  fs/xfs/libxfs/xfs_attr_leaf.c |  82 +++++++++++++++--------
>  fs/xfs/libxfs/xfs_attr_leaf.h |   2 +
>  4 files changed, 158 insertions(+), 78 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index a2fba0c..72af8e2 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -48,6 +48,7 @@ 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_leaf_has_attr(xfs_da_args_t *args, struct xfs_buf **bp);         

Trailing whitespace, and please use "struct xfs_da_args", not the
typedef...

>  
>  /*
>   * Internal routines when attribute list is more than one block.
> @@ -55,6 +56,8 @@ 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);
>  
> @@ -278,6 +281,32 @@ xfs_attr_set_args(
>  }
>  
>  /*
> + * Return EEXIST if attr is found, or ENOATTR if not
> + */
> +int
> +xfs_has_attr(
> +	struct xfs_da_args      *args)
> +{
> +	struct xfs_inode        *dp = args->dp;
> +	struct xfs_buf		*bp;
> +	int                     error;
> +
> +	if (!xfs_inode_hasattr(dp)) {
> +		error = -ENOATTR;
> +	} else if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
> +		ASSERT(dp->i_afp->if_flags & XFS_IFINLINE);
> +		error = xfs_shortform_has_attr(args, NULL, NULL);
> +	} else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
> +		error = xfs_leaf_has_attr(args, &bp);
> +		xfs_trans_brelse(args->trans, bp);
> +	} else {
> +		error = xfs_attr_node_hasname(args, NULL);
> +	}
> +
> +	return error;
> +}
> +
> +/*
>   * Remove the attribute specified in @args.
>   */
>  int
> @@ -616,26 +645,17 @@ 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, -1, &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_leaf_has_attr(args, &bp);
>  	if ((args->flags & ATTR_REPLACE) && (retval == -ENOATTR)) {
>  		xfs_trans_brelse(args->trans, bp);
>  		return retval;
> @@ -787,6 +807,26 @@ xfs_attr_leaf_addname(
>  }
>  
>  /*
> + * Return EEXIST if attr is found, or ENOATTR if not
> + */
> +STATIC int
> +xfs_leaf_has_attr(
> +	struct xfs_da_args      *args,
> +	struct xfs_buf		**bp)
> +{
> +	int                     error = 0;
> +
> +	args->blkno = 0;
> +	error = xfs_attr3_leaf_read(args->trans, args->dp,
> +			args->blkno, -1, bp);

Can we please get rid of these -1 and -2 magic values that eventually
become the mappedbno argument to xfs_dabuf_map?

> +	if (error)
> +		return error;
> +
> +	error = xfs_attr3_leaf_lookup_int(*bp, args);
> +	return error;

"return xfs_attr3_leaf_lookup_int..." ?

> +}
> +
> +/*
>   * Remove a name from the leaf attribute list structure
>   *
>   * This leaf block cannot have a "remote" value, we only call this routine
> @@ -806,12 +846,8 @@ xfs_attr_leaf_removename(
>  	 * Remove the attribute.
>  	 */
>  	dp = args->dp;
> -	args->blkno = 0;
> -	error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno, -1, &bp);
> -	if (error)
> -		return error;
>  
> -	error = xfs_attr3_leaf_lookup_int(bp, args);
> +	error = xfs_leaf_has_attr(args, &bp);
>  	if (error == -ENOATTR) {
>  		xfs_trans_brelse(args->trans, bp);
>  		return error;
> @@ -848,12 +884,7 @@ xfs_attr_leaf_get(xfs_da_args_t *args)
>  
>  	trace_xfs_attr_leaf_get(args);
>  
> -	args->blkno = 0;
> -	error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno, -1, &bp);
> -	if (error)
> -		return error;
> -
> -	error = xfs_attr3_leaf_lookup_int(bp, args);
> +	error = xfs_leaf_has_attr(args, &bp);
>  	if (error != -EEXIST)  {
>  		xfs_trans_brelse(args->trans, bp);
>  		return error;
> @@ -866,6 +897,43 @@ xfs_attr_leaf_get(xfs_da_args_t *args)
>  	return error;
>  }
>  
> +/*
> + * Return EEXIST if attr is found, or ENOATTR if not
> + * statep: If not null is set to point at the found state.  Caller will
> + * 	   be responsible for freeing the state in this case.
> + */
> +STATIC int
> +xfs_attr_node_hasname(
> +	struct xfs_da_args	*args,
> +	struct xfs_da_state	**statep)
> +{
> +	struct xfs_da_state	*state;
> +	struct xfs_inode	*dp;
> +	int			retval, error;
> +
> +	/*
> +	 * Tie a string around our finger to remind us where we are.
> +	 */
> +	dp = args->dp;
> +	state = xfs_da_state_alloc();
> +	state->args = args;
> +	state->mp = dp->i_mount;
> +
> +	/*
> +	 * Search to see if name exists, and get back a pointer to it.
> +	 */
> +	error = xfs_da3_node_lookup_int(state, &retval);
> +	if (error == 0)
> +		error = retval;
> +
> +	if (statep != NULL)
> +		*statep = state;
> +	else
> +		xfs_da_state_free(state);
> +
> +	return error;
> +}
> +
>  /*========================================================================
>   * External routines when attribute list size > geo->blksize
>   *========================================================================*/
> @@ -898,17 +966,14 @@ xfs_attr_node_addname(
>  	dp = args->dp;
>  	mp = dp->i_mount;
>  restart:
> -	state = xfs_da_state_alloc();
> -	state->args = args;
> -	state->mp = mp;
> -
>  	/*
>  	 * Search to see if name already exists, and get back a pointer
>  	 * to where it should go.
>  	 */
> -	error = xfs_da3_node_lookup_int(state, &retval);
> -	if (error)
> +	error = xfs_attr_node_hasname(args, &state);
> +	if (error == -EEXIST)
>  		goto out;
> +
>  	blk = &state->path.blk[ state->path.active-1 ];
>  	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
>  	if ((args->flags & ATTR_REPLACE) && (retval == -ENOATTR)) {
> @@ -1113,29 +1178,15 @@ xfs_attr_node_removename(
>  {
>  	struct xfs_da_state	*state;
>  	struct xfs_da_state_blk	*blk;
> -	struct xfs_inode	*dp;
>  	struct xfs_buf		*bp;
>  	int			retval, error, forkoff;
> +	struct xfs_inode	*dp = args->dp;
>  
>  	trace_xfs_attr_node_removename(args);
>  
> -	/*
> -	 * Tie a string around our finger to remind us where we are.
> -	 */
> -	dp = args->dp;
> -	state = xfs_da_state_alloc();
> -	state->args = args;
> -	state->mp = dp->i_mount;
> -
> -	/*
> -	 * Search to see if name exists, and get back a pointer to it.
> -	 */
> -	error = xfs_da3_node_lookup_int(state, &retval);
> -	if (error || (retval != -EEXIST)) {
> -		if (error == 0)
> -			error = retval;
> +	error = xfs_attr_node_hasname(args, &state);
> +	if (error != -EEXIST)
>  		goto out;
> -	}
>  
>  	/*
>  	 * If there is an out-of-line value, de-allocate the blocks.
> @@ -1355,17 +1406,13 @@ xfs_attr_node_get(xfs_da_args_t *args)
>  
>  	trace_xfs_attr_node_get(args);
>  
> -	state = xfs_da_state_alloc();
> -	state->args = args;
> -	state->mp = args->dp->i_mount;
> -
>  	/*
>  	 * Search to see if name exists, and get back a pointer to it.
>  	 */
> -	error = xfs_da3_node_lookup_int(state, &retval);
> -	if (error) {
> +	error = xfs_attr_node_hasname(args, &state);
> +	if (error != -EEXIST) {
>  		retval = error;
> -	} else if (retval == -EEXIST) {
> +	} else {
>  		blk = &state->path.blk[ state->path.active-1 ];
>  		ASSERT(blk->bp != NULL);
>  		ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index 0bade83..c082d34 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -170,6 +170,7 @@ int xfs_attr_set(struct xfs_inode *dp, struct xfs_name *name,
>  		 unsigned char *value, int valuelen);
>  int xfs_attr_set_args(struct xfs_da_args *args);
>  int xfs_attr_remove(struct xfs_inode *dp, struct xfs_name *name);
> +int xfs_has_attr(struct xfs_da_args *args);
>  int xfs_attr_remove_args(struct xfs_da_args *args);
>  int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
>  		  int flags, struct attrlist_cursor_kern *cursor);
> diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
> index 70eb941..8d2e11f 100644
> --- a/fs/xfs/libxfs/xfs_attr_leaf.c
> +++ b/fs/xfs/libxfs/xfs_attr_leaf.c
> @@ -546,6 +546,53 @@ xfs_attr_shortform_create(xfs_da_args_t *args)
>  }
>  
>  /*
> + * Return EEXIST if attr is found, or ENOATTR if not
> + * args:  args containing attribute name and namelen
> + * sfep:  If not null, pointer will be set to the last attr entry found
> + * basep: If not null, pointer is set to the byte offset of the entry in the
> + *	  list
> + */
> +int
> +xfs_shortform_has_attr(
> +	struct xfs_da_args	 *args,
> +	struct xfs_attr_sf_entry **sfep,
> +	int			 *basep)
> +{
> +	struct xfs_attr_shortform *sf;
> +	struct xfs_attr_sf_entry *sfe;
> +	int			base = sizeof(struct xfs_attr_sf_hdr);
> +	int			size = 0;
> +	int			end;
> +	int			i;
> +
> +	base = sizeof(struct xfs_attr_sf_hdr);
> +	sf = (struct xfs_attr_shortform *)args->dp->i_afp->if_u1.if_data;
> +	sfe = &sf->list[0];
> +	end = sf->hdr.count;
> +	for (i = 0; i < end; sfe = XFS_ATTR_SF_NEXTENTRY(sfe),
> +			base += size, i++) {
> +		size = XFS_ATTR_SF_ENTSIZE(sfe);
> +		if (sfe->namelen != args->namelen)
> +			continue;
> +		if (memcmp(sfe->nameval, args->name, args->namelen) != 0)
> +			continue;
> +		if (!xfs_attr_namesp_match(args->flags, sfe->flags))
> +			continue;
> +		break;
> +	}
> +
> +	if (sfep != NULL)
> +		*sfep = sfe;
> +
> +	if (basep != NULL)
> +		*basep = base;
> +
> +	if (i == end)
> +		return -ENOATTR;
> +	return -EEXIST;
> +}
> +
> +/*
>   * Add a name/value pair to the shortform attribute list.
>   * Overflow from the inode has already been checked for.
>   */
> @@ -554,7 +601,7 @@ xfs_attr_shortform_add(xfs_da_args_t *args, int forkoff)
>  {
>  	xfs_attr_shortform_t *sf;
>  	xfs_attr_sf_entry_t *sfe;
> -	int i, offset, size;
> +	int offset, size, error;
>  	xfs_mount_t *mp;
>  	xfs_inode_t *dp;
>  	struct xfs_ifork *ifp;
> @@ -568,18 +615,11 @@ xfs_attr_shortform_add(xfs_da_args_t *args, int forkoff)
>  	ifp = dp->i_afp;
>  	ASSERT(ifp->if_flags & XFS_IFINLINE);
>  	sf = (xfs_attr_shortform_t *)ifp->if_u1.if_data;
> -	sfe = &sf->list[0];
> -	for (i = 0; i < sf->hdr.count; sfe = XFS_ATTR_SF_NEXTENTRY(sfe), i++) {
> +	error = xfs_shortform_has_attr(args, &sfe, NULL);
>  #ifdef DEBUG
> -		if (sfe->namelen != args->namelen)
> -			continue;
> -		if (memcmp(args->name, sfe->nameval, args->namelen) != 0)
> -			continue;
> -		if (!xfs_attr_namesp_match(args->flags, sfe->flags))
> -			continue;
> +	if (error == -EEXIST)
>  		ASSERT(0);

ASSERT(error != -EEXIST); ?  Without the #ifdef DEBUG since ASSERT does
nothing if DEBUG isn't defined...

>  #endif
> -	}
>  
>  	offset = (char *)sfe - (char *)sf;
>  	size = XFS_ATTR_SF_ENTSIZE_BYNAME(args->namelen, args->valuelen);
> @@ -626,7 +666,7 @@ xfs_attr_shortform_remove(xfs_da_args_t *args)
>  {
>  	xfs_attr_shortform_t *sf;
>  	xfs_attr_sf_entry_t *sfe;
> -	int base, size=0, end, totsize, i;
> +	int base, size = 0, end, totsize, error;
>  	xfs_mount_t *mp;
>  	xfs_inode_t *dp;

Please fix the typedef and indentation here while you're changing this
(and all the other attr) functions.

Otherwise, I very much like this cleanup. :)

--D

>  
> @@ -634,23 +674,13 @@ xfs_attr_shortform_remove(xfs_da_args_t *args)
>  
>  	dp = args->dp;
>  	mp = dp->i_mount;
> -	base = sizeof(xfs_attr_sf_hdr_t);
>  	sf = (xfs_attr_shortform_t *)dp->i_afp->if_u1.if_data;
> -	sfe = &sf->list[0];
>  	end = sf->hdr.count;
> -	for (i = 0; i < end; sfe = XFS_ATTR_SF_NEXTENTRY(sfe),
> -					base += size, i++) {
> -		size = XFS_ATTR_SF_ENTSIZE(sfe);
> -		if (sfe->namelen != args->namelen)
> -			continue;
> -		if (memcmp(sfe->nameval, args->name, args->namelen) != 0)
> -			continue;
> -		if (!xfs_attr_namesp_match(args->flags, sfe->flags))
> -			continue;
> -		break;
> -	}
> -	if (i == end)
> -		return -ENOATTR;
> +
> +	error = xfs_shortform_has_attr(args, &sfe, &base);
> +	if (error == -ENOATTR)
> +		return error;
> +	size = XFS_ATTR_SF_ENTSIZE(sfe);
>  
>  	/*
>  	 * Fix up the attribute fork data, covering the hole
> diff --git a/fs/xfs/libxfs/xfs_attr_leaf.h b/fs/xfs/libxfs/xfs_attr_leaf.h
> index 7b74e18..be1f636 100644
> --- a/fs/xfs/libxfs/xfs_attr_leaf.h
> +++ b/fs/xfs/libxfs/xfs_attr_leaf.h
> @@ -39,6 +39,8 @@ int	xfs_attr_shortform_getvalue(struct xfs_da_args *args);
>  int	xfs_attr_shortform_to_leaf(struct xfs_da_args *args,
>  			struct xfs_buf **leaf_bp);
>  int	xfs_attr_shortform_remove(struct xfs_da_args *args);
> +int	xfs_shortform_has_attr(struct xfs_da_args *args,
> +			       struct xfs_attr_sf_entry **sfep, int *basep);
>  int	xfs_attr_shortform_allfit(struct xfs_buf *bp, struct xfs_inode *dp);
>  int	xfs_attr_shortform_bytesfit(struct xfs_inode *dp, int bytes);
>  xfs_failaddr_t xfs_attr_shortform_verify(struct xfs_inode *ip);
> -- 
> 2.7.4
>