I'm sending this to linux-fsdevel because one of the patches affects vfs. GFS2 has a long-standing deadlock related to the transition of dinodes from the Unlinked state to the Deleted state. The problem is that function delete_work_func in glock.c called gfs2_lookup_by_inum, which locks the inode glock before performing the rest of its checks, which means the lock order is different from the normal lookups. My original idea was to make delete_work_func call the normal lookup function, and do away with the non-blocking lookups so they had the same lock order. But we decided that was a bad idea. So the first two patches revert the changes I had made earlier toward that end. The next five patches implement a new design by Andreas Gruenbacher, which allows for more flexibility in waiting for freeing inodes. These missed transitions from unlinked to free also had another side-effect: It often failed to acquire the lock and gave up, which meant that slowly over time, the "df" value would get out of sync with "du." So it appeared that the file system was more full than it was. (These unlinked dinodes should, in theory, be reclaimed automatically, but they still threw the numbers off, because the "unlinked" dinodes were not considered free space.) This patch set has undergone rigorous testing that reliably recreated the deadlock. Normally, the deadlock appeared in about an hour or two of testing. With these patches, it's been running for weeks without a problem. Signed-off-by: Bob Peterson <rpeterso@xxxxxxxxxx> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
