Commit de631e1a authored by Dave Chinner's avatar Dave Chinner Committed by Christian Brauner
Browse files

xfs: use kvmalloc for xattr buffers 



Pankaj Raghav reported that when filesystem block size is larger
than page size, the xattr code can use kmalloc() for high order
allocations. This triggers a useless warning in the allocator as it
is a __GFP_NOFAIL allocation here:

static inline
struct page *rmqueue(struct zone *preferred_zone,
                        struct zone *zone, unsigned int order,
                        gfp_t gfp_flags, unsigned int alloc_flags,
                        int migratetype)
{
        struct page *page;

        /*
         * We most definitely don't want callers attempting to
         * allocate greater than order-1 page units with __GFP_NOFAIL.
         */
>>>>    WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
...

Fix this by changing all these call sites to use kvmalloc(), which
will strip the NOFAIL from the kmalloc attempt and if that fails
will do a __GFP_NOFAIL vmalloc().

This is not an issue that productions systems will see as
filesystems with block size > page size cannot be mounted by the
kernel; Pankaj is developing this functionality right now.

Reported-by: default avatarPankaj Raghav <kernel@pankajraghav.com>
Fixes: f078d4ea ("xfs: convert kmem_alloc() to kmalloc()")
Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20240822135018.1931258-8-kernel@pankajraghav.com


Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarPankaj Raghav <p.raghav@samsung.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarDaniel Gomez <da.gomez@samsung.com>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 10553a91

fs/xfs/libxfs/xfs_attr_leaf.c

+6 −9
Original line number Diff line number Diff line
@@ -1138,10 +1138,7 @@ xfs_attr3_leaf_to_shortform( 


	trace_xfs_attr_leaf_to_sf(args);



	tmpbuffer = kmalloc(args->geo->blksize, GFP_KERNEL | __GFP_NOFAIL);

	if (!tmpbuffer)

		return -ENOMEM;



	tmpbuffer = kvmalloc(args->geo->blksize, GFP_KERNEL | __GFP_NOFAIL);

	memcpy(tmpbuffer, bp->b_addr, args->geo->blksize);



	leaf = (xfs_attr_leafblock_t *)tmpbuffer;
@@ -1205,7 +1202,7 @@ xfs_attr3_leaf_to_shortform( 
	error = 0;



out:

	kfree(tmpbuffer);

	kvfree(tmpbuffer);

	return error;

}
@@ -1613,7 +1610,7 @@ xfs_attr3_leaf_compact( 


	trace_xfs_attr_leaf_compact(args);



	tmpbuffer = kmalloc(args->geo->blksize, GFP_KERNEL | __GFP_NOFAIL);

	tmpbuffer = kvmalloc(args->geo->blksize, GFP_KERNEL | __GFP_NOFAIL);

	memcpy(tmpbuffer, bp->b_addr, args->geo->blksize);

	memset(bp->b_addr, 0, args->geo->blksize);

	leaf_src = (xfs_attr_leafblock_t *)tmpbuffer;
@@ -1651,7 +1648,7 @@ xfs_attr3_leaf_compact( 
	 */

	xfs_trans_log_buf(trans, bp, 0, args->geo->blksize - 1);



	kfree(tmpbuffer);

	kvfree(tmpbuffer);

}



/*
@@ -2330,7 +2327,7 @@ xfs_attr3_leaf_unbalance( 
		struct xfs_attr_leafblock *tmp_leaf;

		struct xfs_attr3_icleaf_hdr tmphdr;



		tmp_leaf = kzalloc(state->args->geo->blksize,

		tmp_leaf = kvzalloc(state->args->geo->blksize,

				GFP_KERNEL | __GFP_NOFAIL);



		/*
@@ -2371,7 +2368,7 @@ xfs_attr3_leaf_unbalance( 
		}

		memcpy(save_leaf, tmp_leaf, state->args->geo->blksize);

		savehdr = tmphdr; /* struct copy */

		kfree(tmp_leaf);

		kvfree(tmp_leaf);

	}



	xfs_attr3_leaf_hdr_to_disk(state->args->geo, save_leaf, &savehdr);