GFS2: glock livelock
This patch fixes a couple gfs2 problems with the reclaiming of
unlinked dinodes. First, there were a couple of livelocks where
everything would come to a halt waiting for a glock that was
seemingly held by a process that no longer existed. In fact, the
process did exist, it just had the wrong pid number in the holder
information. Second, there was a lock ordering problem between
inode locking and glock locking. Third, glock/inode contention
could sometimes cause inodes to be improperly marked invalid by
iget_failed.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 503b842..3739155 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -948,18 +948,20 @@
* try_rgrp_unlink - Look for any unlinked, allocated, but unused inodes
* @rgd: The rgrp
*
- * Returns: The inode, if one has been found
+ * Returns: 0 if no error
+ * The inode, if one has been found, in inode.
*/
-static struct inode *try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked,
- u64 skip)
+static int try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked,
+ u64 skip, struct inode **inode)
{
- struct inode *inode;
u32 goal = 0, block;
u64 no_addr;
struct gfs2_sbd *sdp = rgd->rd_sbd;
unsigned int n;
+ int error = 0;
+ *inode = NULL;
for(;;) {
if (goal >= rgd->rd_data)
break;
@@ -979,14 +981,14 @@
if (no_addr == skip)
continue;
*last_unlinked = no_addr;
- inode = gfs2_inode_lookup(rgd->rd_sbd->sd_vfs, DT_UNKNOWN,
- no_addr, -1, 1);
- if (!IS_ERR(inode))
- return inode;
+ error = gfs2_unlinked_inode_lookup(rgd->rd_sbd->sd_vfs,
+ no_addr, inode);
+ if (*inode || error)
+ return error;
}
rgd->rd_flags &= ~GFS2_RDF_CHECK;
- return NULL;
+ return 0;
}
/**
@@ -1096,12 +1098,27 @@
case 0:
if (try_rgrp_fit(rgd, al))
goto out;
- if (rgd->rd_flags & GFS2_RDF_CHECK)
- inode = try_rgrp_unlink(rgd, last_unlinked, ip->i_no_addr);
+ /* If the rg came in already locked, there's no
+ way we can recover from a failed try_rgrp_unlink
+ because that would require an iput which can only
+ happen after the rgrp is unlocked. */
+ if (!rg_locked && rgd->rd_flags & GFS2_RDF_CHECK)
+ error = try_rgrp_unlink(rgd, last_unlinked,
+ ip->i_no_addr, &inode);
if (!rg_locked)
gfs2_glock_dq_uninit(&al->al_rgd_gh);
- if (inode)
+ if (inode) {
+ if (error) {
+ if (inode->i_state & I_NEW)
+ iget_failed(inode);
+ else
+ iput(inode);
+ return ERR_PTR(error);
+ }
return inode;
+ }
+ if (error)
+ return ERR_PTR(error);
/* fall through */
case GLR_TRYFAILED:
rgd = recent_rgrp_next(rgd);
@@ -1130,12 +1147,23 @@
case 0:
if (try_rgrp_fit(rgd, al))
goto out;
- if (rgd->rd_flags & GFS2_RDF_CHECK)
- inode = try_rgrp_unlink(rgd, last_unlinked, ip->i_no_addr);
+ if (!rg_locked && rgd->rd_flags & GFS2_RDF_CHECK)
+ error = try_rgrp_unlink(rgd, last_unlinked,
+ ip->i_no_addr, &inode);
if (!rg_locked)
gfs2_glock_dq_uninit(&al->al_rgd_gh);
- if (inode)
+ if (inode) {
+ if (error) {
+ if (inode->i_state & I_NEW)
+ iget_failed(inode);
+ else
+ iput(inode);
+ return ERR_PTR(error);
+ }
return inode;
+ }
+ if (error)
+ return ERR_PTR(error);
break;
case GLR_TRYFAILED: