fs/unionfs: remove excessive protection to avoid deadlock #2532
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Summary
fs/unionfs: remove excessive protection to avoid deadlock
Deadlock during recursive access if unionfs overlays procfs,
check the critical segment only and remove the useless protection part.
original call stack:
(gdb) bt
Impact
mount -t procfs /proc1
mount -t hostfs -o fs=/proc/net /net2
mount -t unionfs -o fspath1=/proc1,fspath2=/net2,prefix2=net /proc
Testing
mount -t procfs /proc1
mount -t hostfs -o fs=/proc/net /net2
mount -t unionfs -o fspath1=/proc1,fspath2=/net2,prefix2=net /proc
readdir recursive from /proc mount point