path: root/include/linux/fs.h
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authorJ. Bruce Fields <bfields@redhat.com>2012-03-05 11:40:41 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2013-11-09 00:16:40 -0500
commit6cedba8962f440c72447f811d0d530a8a9dc637a (patch)
tree740e74df27113d34d06da011b3c5561d19eb3349 /include/linux/fs.h
parent40bd22c9f8617ddd5da06044c81f72a2cf700791 (diff)
vfs: take i_mutex on renamed file
A read delegation is used by NFSv4 as a guarantee that a client can perform local read opens without informing the server. The open operation takes the last component of the pathname as an argument, thus is also a lookup operation, and giving the client the above guarantee means informing the client before we allow anything that would change the set of names pointing to the inode. Therefore, we need to break delegations on rename, link, and unlink. We also need to prevent new delegations from being acquired while one of these operations is in progress. We could add some completely new locking for that purpose, but it's simpler to use the i_mutex, since that's already taken by all the operations we care about. The single exception is rename. So, modify rename to take the i_mutex on the file that is being renamed. Also fix up lockdep and Documentation/filesystems/directory-locking to reflect the change. Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/linux/fs.h')
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