ovl: get exclusive ownership on upper/work dirs

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Bad things can happen if several concurrent overlay mounts try to
use the same upperdir/workdir path.

Try to get the 'inuse' advisory lock on upperdir and workdir.
Fail mount if another overlay mount instance or another user
holds the 'inuse' lock on these directories.

Note that this provides no protection for concurrent overlay
mount that use overlapping (i.e. descendant) upper/work dirs.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

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Amir Goldstein 2017-06-21 15:28:33 +03:00 • committed by Miklos Szeredi

parent ad0af7104d

commit 2cac0c00a6

2 changed files with 29 additions and 3 deletions

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3

fs/overlayfs/ovl_entry.h

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29

fs/overlayfs/super.c

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