From c93c09a057b71fa152de9d56f971fd82248d6499 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Wed, 8 Feb 2017 14:30:53 -0800 Subject: mm: avoid returning VM_FAULT_RETRY from ->page_mkwrite handlers [ Upstream commit 0911d0041c22922228ca52a977d7b0b0159fee4b ] Some ->page_mkwrite handlers may return VM_FAULT_RETRY as its return code (GFS2 or Lustre can definitely do this). However VM_FAULT_RETRY from ->page_mkwrite is completely unhandled by the mm code and results in locking and writeably mapping the page which definitely is not what the caller wanted. Fix Lustre and block_page_mkwrite_ret() used by other filesystems (notably GFS2) to return VM_FAULT_NOPAGE instead which results in bailing out from the fault code, the CPU then retries the access, and we fault again effectively doing what the handler wanted. Link: http://lkml.kernel.org/r/20170203150729.15863-1-jack@suse.cz Signed-off-by: Jan Kara Reported-by: Al Viro Reviewed-by: Jinshan Xiong Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- include/linux/buffer_head.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 447a915db25d..4431ea2c8802 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -239,12 +239,10 @@ static inline int block_page_mkwrite_return(int err) { if (err == 0) return VM_FAULT_LOCKED; - if (err == -EFAULT) + if (err == -EFAULT || err == -EAGAIN) return VM_FAULT_NOPAGE; if (err == -ENOMEM) return VM_FAULT_OOM; - if (err == -EAGAIN) - return VM_FAULT_RETRY; /* -ENOSPC, -EDQUOT, -EIO ... */ return VM_FAULT_SIGBUS; } -- cgit v1.2.3