xfs: use KM_NOFS for allocations during attribute list operations (622d8149) · Commits · 戴 / test

When listing attributes, we are doiing memory allocations under the inode ilock using only KM_SLEEP. This allows memory allocation to recurse back into the filesystem and do writeback, which may the ilock we already hold on the current inode. THis will deadlock. Hence use KM_NOFS for such allocations outside of transaction context to ensure that reclaim recursion does not occur. Reported-by:

Nick Piggin <npiggin@gmail.com> Signed-off-by:

Dave Chinner <dchinner@redhat.com> Reviewed-by:

Christoph Hellwig <hch@lst.de>

fs/xfs/xfs_attr_leaf.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -637,7 +637,7 @@ xfs_attr_shortform_list(xfs_attr_list_context_t *context)
		* It didn't all fit, so we have to sort everything on hashval.
		*/
		sbsize = sf->hdr.count * sizeof(*sbuf);
		sbp = sbuf = kmem_alloc(sbsize, KM_SLEEP);
		sbp = sbuf = kmem_alloc(sbsize, KM_SLEEP \| KM_NOFS);

		/*
		* Scan the attribute list for the rest of the entries, storing
		@@ -2386,7 +2386,7 @@ xfs_attr_leaf_list_int(xfs_dabuf_t bp, xfs_attr_list_context_t context)
		args.dp = context->dp;
		args.whichfork = XFS_ATTR_FORK;
		args.valuelen = valuelen;
		args.value = kmem_alloc(valuelen, KM_SLEEP);
		args.value = kmem_alloc(valuelen, KM_SLEEP \| KM_NOFS);
		args.rmtblkno = be32_to_cpu(name_rmt->valueblk);
		args.rmtblkcnt = XFS_B_TO_FSB(args.dp->i_mount, valuelen);
		retval = xfs_attr_rmtval_get(&args);

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