GFS2: glock livelock

[safe/jmp/linux-2.6] / fs / gfs2 / rgrp.c

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 503b842..3739155 100644 (file)
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -948,18 +948,20 @@ static int try_rgrp_fit(struct gfs2_rgrpd *rgd, struct gfs2_alloc *al)
  * 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 @@ static struct inode *try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked,
                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 @@ static struct inode *get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked)
                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 @@ static struct inode *get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked)
                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: