Commit 9a56c213 authored by Oleg Drokin's avatar Oleg Drokin Committed by Linus Torvalds
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[PATCH] Add lookup_instantiate_filp usage warning

I think it would be nice to put an usage warning in header of
lookup_instantiate_filp() to indicate it is unsafe to use it on anything
but regular files (even that is potentially unsafe, but there your ->open()
is usually in your hands anyway), so that others won't fall into the same
trap I did.
Signed-off-by: default avatarOleg Drokin <>
Cc: Trond Myklebust <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent b500531e
......@@ -890,6 +890,10 @@ EXPORT_SYMBOL(filp_open);
* a fully instantiated struct file to the caller.
* This function is meant to be called from within a filesystem's
* lookup method.
* Beware of calling it for non-regular files! Those ->open methods might block
* (e.g. in fifo_open), leaving you with parent locked (and in case of fifo,
* leading to a deadlock, as nobody can open that fifo anymore, because
* another process to open fifo will block on locked parent when doing lookup).
* Note that in case of error, nd-> is destroyed, but the
* path information remains valid.
* If the open callback is set to NULL, then the standard f_op->open()
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