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author | Louis Rilling <Louis.Rilling@kerlabs.com> | 2008-06-16 19:01:01 +0200 |
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committer | Mark Fasheh <mfasheh@suse.com> | 2008-07-14 13:57:16 -0700 |
commit | b3e76af87441fc36eef3516d73ab2314e7b2d911 (patch) | |
tree | 36c6c6a21ac16b609302845a7dcb91749a972e4c /fs/dcookies.c | |
parent | 107ed40bd070df5e4a0a012042c45c40963dc574 (diff) |
configfs: Fix deadlock with racing rmdir() and rename()
This patch fixes the deadlock between racing sys_rename() and configfs_rmdir().
The idea is to avoid locking i_mutexes of default groups in
configfs_detach_prep(), and rely instead on the new configfs_dirent_lock to
protect against configfs_dirent's linkage mutations. To ensure that an mkdir()
racing with rmdir() will not create new items in a to-be-removed default group,
we make configfs_new_dirent() check for the CONFIGFS_USET_DROPPING flag right
before linking the new dirent, and return error if the flag is set. This makes
racing mkdir()/symlink()/dir_open() fail in places where errors could already
happen, resp. in (attach_item()|attach_group())/create_link()/new_dirent().
configfs_depend() remains safe since it locks all the path from configfs root,
and is thus mutually exclusive with rmdir().
An advantage of this is that now detach_groups() unconditionnaly takes the
default groups i_mutex, which makes it more consistent with populate_groups().
Signed-off-by: Louis Rilling <Louis.Rilling@kerlabs.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Diffstat (limited to 'fs/dcookies.c')
0 files changed, 0 insertions, 0 deletions