This patch set my Bob and me avoids a deadlock in gfs2 when an inode is being freed: normally, when find_inode finds an inode in I_FREEING or I_WILL_FREE state, it waits for the inode to go away before returning (__wait_on_freeing_inode). Freeing an inode on gfs2 requires taking the inode's glock. However, in gfs2_lookup_by_inum, we need to be holding the inode glock while doing lookups, so we can deadlock with processes concurrently freeing inodes.
This patch set allows gfs2_lookup_by_inum to drop the inode glock before waiting for inodes to go away. We could try non-blocking lookups and wait for an arbitrary amount of time before retrying the lookup instead as well, but waiting for the actual event (i.e., the inode being freed to likely have disappeared) makes more sense. Thanks, Andreas Andreas Gruenbacher (5): GFS2: Remove superfluous assignment GFS2: No need for non-blocking gfs2_ilookup in delete_work_func vfs: Introduce prepare_wait_on_freeing_inode GFS2: Use non-blocking wait in gfs2_iget GFS2: Prevent deadlock in gfs2_lookup_by_inum Bob Peterson (2): Revert "GFS2: Eliminate parameter non_block on gfs2_inode_lookup" Revert "GFS2: Don't filter out I_FREEING inodes anymore" fs/gfs2/dir.c | 2 +- fs/gfs2/glock.c | 4 +- fs/gfs2/inode.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++----- fs/gfs2/inode.h | 8 +++- fs/gfs2/ops_fstype.c | 2 +- fs/inode.c | 18 +++++++-- include/linux/fs.h | 1 + include/linux/wait.h | 21 +++++++--- 8 files changed, 142 insertions(+), 23 deletions(-) -- 2.5.5
