iomap: Call inode_dio_end() before generic_write_sync()
iomap complete routine can deadlock with btrfs_fallocate because of the
call to generic_write_sync().
P0 P1
inode_lock() fallocate(FALLOC_FL_ZERO_RANGE)
__iomap_dio_rw() inode_lock()
<block>
<submits IO>
<completes IO>
inode_unlock()
<gets inode_lock()>
inode_dio_wait()
iomap_dio_complete()
generic_write_sync()
btrfs_file_fsync()
inode_lock()
<deadlock>
inode_dio_end() is used to notify the end of DIO data in order
to synchronize with truncate. Call inode_dio_end() before calling
generic_write_sync(), so filesystems can lock i_rwsem during a sync.
This matches the way it is done in fs/direct-io.c:dio_complete().
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index b005ef5..933f234 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -118,6 +118,7 @@
dio_warn_stale_pagecache(iocb->ki_filp);
}
+ inode_dio_end(file_inode(iocb->ki_filp));
/*
* If this is a DSYNC write, make sure we push it to stable storage now
* that we've written data.
@@ -125,7 +126,6 @@
if (ret > 0 && (dio->flags & IOMAP_DIO_NEED_SYNC))
ret = generic_write_sync(iocb, ret);
- inode_dio_end(file_inode(iocb->ki_filp));
kfree(dio);
return ret;
