From 1a31182edd0083bb9f26e582ed39f92f898c4d0a Mon Sep 17 00:00:00 2001 From: Goldwyn Rodrigues Date: Mon, 28 Sep 2020 08:51:08 -0700 Subject: 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() inode_unlock() inode_dio_wait() iomap_dio_complete() generic_write_sync() btrfs_file_fsync() inode_lock() 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 Reviewed-by: Christoph Hellwig Reviewed-by: Josef Bacik Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/iomap/direct-io.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/iomap') diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index b005ef5f554e..933f234d5bec 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -118,6 +118,7 @@ ssize_t iomap_dio_complete(struct iomap_dio *dio) 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 @@ ssize_t iomap_dio_complete(struct iomap_dio *dio) 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; -- cgit v1.2.3