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authorJan Kara <jack@suse.cz>2017-02-08 14:30:53 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-12-09 18:42:43 +0100
commitcc4add389789f89018fa6705cd8e02d6b6cab67d (patch)
tree7098a36ab05899a47962d49313f0f784cdaced25 /include
parent1b7dbabf0242e7742decae10555886474de8628d (diff)
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 <jack@suse.cz> Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/buffer_head.h4
1 files changed, 1 insertions, 3 deletions
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 89d9aa9e79bf..6fe974dbe741 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -234,12 +234,10 @@ 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;
}