Commit aee9a4a5 authored May 22, 2018 by Darrick J. Wong

fs: clear writeback errors in inode_init_always



In inode_init_always(), we clear the inode mapping flags, which clears
any retained error (AS_EIO, AS_ENOSPC) bits.  Unfortunately, we do not
also clear wb_err, which means that old mapping errors can leak through
to new inodes.

This is crucial for the XFS inode allocation path because we recycle old
in-core inodes and we do not want error state from an old file to leak
into the new file.  This bug was discovered by running generic/036 and
generic/047 in a loop and noticing that the EIOs generated by the
collision of direct and buffered writes in generic/036 would survive the
remount between 036 and 047, and get reported to the fsyncs (on
different files!) in generic/047.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Brian Foster <bfoster@redhat.com>

parent 19e12961

fs/inode.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -178,6 +178,7 @@ int inode_init_always(struct super_block sb, struct inode inode)
		mapping->a_ops = &empty_aops;
		mapping->host = inode;
		mapping->flags = 0;
		mapping->wb_err = 0;
		atomic_set(&mapping->i_mmap_writable, 0);
		mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
		mapping->private_data = NULL;

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