Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-fixes

* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-fixes:
  GFS2: Fix inode deallocation race

5 files changed, 98 insertions, 216 deletions

diff --git a/fs/gfs2/export.c b/fs/gfs2/export.c
index 06d582732d34..5ab3839dfcb9 100644
--- a/fs/gfs2/export.c
+++ b/fs/gfs2/export.c
@@ -138,10 +138,8 @@ static struct dentry *gfs2_get_dentry(struct super_block *sb,
                                       struct gfs2_inum_host *inum)
 {
         struct gfs2_sbd *sdp = sb->s_fs_info;
-        struct gfs2_holder i_gh;
         struct inode *inode;
         struct dentry *dentry;
-        int error;
 
         inode = gfs2_ilookup(sb, inum->no_addr);
         if (inode) {
@@ -152,52 +150,16 @@ static struct dentry *gfs2_get_dentry(struct super_block *sb,
                 goto out_inode;
         }
 
-        error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
-                                  LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
-        if (error)
-                return ERR_PTR(error);
-
-        error = gfs2_check_blk_type(sdp, inum->no_addr, GFS2_BLKST_DINODE);
-        if (error)
-                goto fail;
-
-        inode = gfs2_inode_lookup(sb, DT_UNKNOWN, inum->no_addr, 0);
-        if (IS_ERR(inode)) {
-                error = PTR_ERR(inode);
-                goto fail;
-        }
-
-        error = gfs2_inode_refresh(GFS2_I(inode));
-        if (error) {
-                iput(inode);
-                goto fail;
-        }
-
-        /* Pick up the works we bypass in gfs2_inode_lookup */
-        if (inode->i_state & I_NEW) 
-                gfs2_set_iop(inode);
-
-        if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
-                iput(inode);
-                goto fail;
-        }
-
-        error = -EIO;
-        if (GFS2_I(inode)->i_diskflags & GFS2_DIF_SYSTEM) {
-                iput(inode);
-                goto fail;
-        }
-
-        gfs2_glock_dq_uninit(&i_gh);
+        inode = gfs2_lookup_by_inum(sdp, inum->no_addr, &inum->no_formal_ino,
+                                    GFS2_BLKST_DINODE);
+        if (IS_ERR(inode))
+                return ERR_CAST(inode);
 
 out_inode:
         dentry = d_obtain_alias(inode);
         if (!IS_ERR(dentry))
                 dentry->d_op = &gfs2_dops;
         return dentry;
-fail:
-        gfs2_glock_dq_uninit(&i_gh);
-        return ERR_PTR(error);
 }
 
 static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 87778857f099..f92c17704169 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -686,21 +686,20 @@ static void delete_work_func(struct work_struct *work)
 {
         struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
         struct gfs2_sbd *sdp = gl->gl_sbd;
-        struct gfs2_inode *ip = NULL;
+        struct gfs2_inode *ip;
         struct inode *inode;
-        u64 no_addr = 0;
+        u64 no_addr = gl->gl_name.ln_number;
+
+        ip = gl->gl_object;
+        /* Note: Unsafe to dereference ip as we don't hold right refs/locks */
 
-        spin_lock(&gl->gl_spin);
-        ip = (struct gfs2_inode *)gl->gl_object;
         if (ip)
-                no_addr = ip->i_no_addr;
-        spin_unlock(&gl->gl_spin);
-        if (ip) {
                 inode = gfs2_ilookup(sdp->sd_vfs, no_addr);
-                if (inode) {
-                        d_prune_aliases(inode);
-                        iput(inode);
-                }
+        else
+                inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
+        if (inode && !IS_ERR(inode)) {
+                d_prune_aliases(inode);
+                iput(inode);
         }
         gfs2_glock_put(gl);
 }
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 06370f8bd8cf..e1213f7f9217 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -73,49 +73,6 @@ static struct inode *gfs2_iget(struct super_block *sb, u64 no_addr)
         return iget5_locked(sb, hash, iget_test, iget_set, &no_addr);
 }
 
-struct gfs2_skip_data {
-        u64     no_addr;
-        int     skipped;
-};
-
-static int iget_skip_test(struct inode *inode, void *opaque)
-{
-        struct gfs2_inode *ip = GFS2_I(inode);
-        struct gfs2_skip_data *data = opaque;
-
-        if (ip->i_no_addr == data->no_addr) {
-                if (inode->i_state & (I_FREEING|I_WILL_FREE)){
-                        data->skipped = 1;
-                        return 0;
-                }
-                return 1;
-        }
-        return 0;
-}
-
-static int iget_skip_set(struct inode *inode, void *opaque)
-{
-        struct gfs2_inode *ip = GFS2_I(inode);
-        struct gfs2_skip_data *data = opaque;
-
-        if (data->skipped)
-                return 1;
-        inode->i_ino = (unsigned long)(data->no_addr);
-        ip->i_no_addr = data->no_addr;
-        return 0;
-}
-
-static struct inode *gfs2_iget_skip(struct super_block *sb,
-                                    u64 no_addr)
-{
-        struct gfs2_skip_data data;
-        unsigned long hash = (unsigned long)no_addr;
-
-        data.no_addr = no_addr;
-        data.skipped = 0;
-        return iget5_locked(sb, hash, iget_skip_test, iget_skip_set, &data);
-}
-
 /**
  * GFS2 lookup code fills in vfs inode contents based on info obtained
  * from directory entry inside gfs2_inode_lookup(). This has caused issues
@@ -243,93 +200,54 @@ fail:
         return ERR_PTR(error);
 }
 
-/**
- * gfs2_process_unlinked_inode - Lookup an unlinked inode for reclamation
- *                               and try to reclaim it by doing iput.
- *
- * This function assumes no rgrp locks are currently held.
- *
- * @sb: The super block
- * no_addr: The inode number
- *
- */
-
-void gfs2_process_unlinked_inode(struct super_block *sb, u64 no_addr)
+struct inode *gfs2_lookup_by_inum(struct gfs2_sbd *sdp, u64 no_addr,
+                                  u64 *no_formal_ino, unsigned int blktype)
 {
-        struct gfs2_sbd *sdp;
-        struct gfs2_inode *ip;
-        struct gfs2_glock *io_gl = NULL;
-        int error;
-        struct gfs2_holder gh;
+        struct super_block *sb = sdp->sd_vfs;
+        struct gfs2_holder i_gh;
         struct inode *inode;
+        int error;
 
-        inode = gfs2_iget_skip(sb, no_addr);
-
-        if (!inode)
-                return;
-
-        /* If it's not a new inode, someone's using it, so leave it alone. */
-        if (!(inode->i_state & I_NEW)) {
-                iput(inode);
-                return;
-        }
-
-        ip = GFS2_I(inode);
-        sdp = GFS2_SB(inode);
-        ip->i_no_formal_ino = -1;
+        error = gfs2_glock_nq_num(sdp, no_addr, &gfs2_inode_glops,
+                                  LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
+        if (error)
+                return ERR_PTR(error);
 
-        error = gfs2_glock_get(sdp, no_addr, &gfs2_inode_glops, CREATE, &ip->i_gl);
-        if (unlikely(error))
+        error = gfs2_check_blk_type(sdp, no_addr, blktype);
+        if (error)
                 goto fail;
-        ip->i_gl->gl_object = ip;
 
-        error = gfs2_glock_get(sdp, no_addr, &gfs2_iopen_glops, CREATE, &io_gl);
-        if (unlikely(error))
-                goto fail_put;
-
-        set_bit(GIF_INVALID, &ip->i_flags);
-        error = gfs2_glock_nq_init(io_gl, LM_ST_SHARED, LM_FLAG_TRY | GL_EXACT,
-                                   &ip->i_iopen_gh);
-        if (unlikely(error))
-                goto fail_iopen;
+        inode = gfs2_inode_lookup(sb, DT_UNKNOWN, no_addr, 0);
+        if (IS_ERR(inode))
+                goto fail;
 
-        ip->i_iopen_gh.gh_gl->gl_object = ip;
-        gfs2_glock_put(io_gl);
-        io_gl = NULL;
+        error = gfs2_inode_refresh(GFS2_I(inode));
+        if (error)
+                goto fail_iput;
 
-        inode->i_mode = DT2IF(DT_UNKNOWN);
+        /* Pick up the works we bypass in gfs2_inode_lookup */
+        if (inode->i_state & I_NEW) 
+                gfs2_set_iop(inode);
 
-        /*
-         * We must read the inode in order to work out its type in
-         * this case. Note that this doesn't happen often as we normally
-         * know the type beforehand. This code path only occurs during
-         * unlinked inode recovery (where it is safe to do this glock,
-         * which is not true in the general case).
-         */
-        error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, LM_FLAG_TRY,
-                                   &gh);
-        if (unlikely(error))
-                goto fail_glock;
+        /* Two extra checks for NFS only */
+        if (no_formal_ino) {
+                error = -ESTALE;
+                if (GFS2_I(inode)->i_no_formal_ino != *no_formal_ino)
+                        goto fail_iput;
 
-        /* Inode is now uptodate */
-        gfs2_glock_dq_uninit(&gh);
-        gfs2_set_iop(inode);
+                error = -EIO;
+                if (GFS2_I(inode)->i_diskflags & GFS2_DIF_SYSTEM)
+                        goto fail_iput;
 
-        /* The iput will cause it to be deleted. */
-        iput(inode);
-        return;
+                error = 0;
+        }
 
-fail_glock:
-        gfs2_glock_dq(&ip->i_iopen_gh);
-fail_iopen:
-        if (io_gl)
-                gfs2_glock_put(io_gl);
-fail_put:
-        ip->i_gl->gl_object = NULL;
-        gfs2_glock_put(ip->i_gl);
 fail:
-        iget_failed(inode);
-        return;
+        gfs2_glock_dq_uninit(&i_gh);
+        return error ? ERR_PTR(error) : inode;
+fail_iput:
+        iput(inode);
+        goto fail;
 }
 
 static int gfs2_dinode_in(struct gfs2_inode *ip, const void *buf)
diff --git a/fs/gfs2/inode.h b/fs/gfs2/inode.h
index 6720d7d5fbc6..d8499fadcc53 100644
--- a/fs/gfs2/inode.h
+++ b/fs/gfs2/inode.h
@@ -99,7 +99,9 @@ err:
 extern void gfs2_set_iop(struct inode *inode);
 extern struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned type, 
                                        u64 no_addr, u64 no_formal_ino);
-extern void gfs2_process_unlinked_inode(struct super_block *sb, u64 no_addr);
+extern struct inode *gfs2_lookup_by_inum(struct gfs2_sbd *sdp, u64 no_addr,
+                                         u64 *no_formal_ino,
+                                         unsigned int blktype);
 extern struct inode *gfs2_ilookup(struct super_block *sb, u64 no_addr);
 
 extern int gfs2_inode_refresh(struct gfs2_inode *ip);
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index bef3ab6cf5c1..33c8407b876f 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -963,17 +963,18 @@ static int try_rgrp_fit(struct gfs2_rgrpd *rgd, struct gfs2_alloc *al)
  *          The inode, if one has been found, in inode.
  */
 
-static u64 try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked,
-                           u64 skip)
+static void try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked, u64 skip)
 {
         u32 goal = 0, block;
         u64 no_addr;
         struct gfs2_sbd *sdp = rgd->rd_sbd;
         unsigned int n;
+        struct gfs2_glock *gl;
+        struct gfs2_inode *ip;
+        int error;
+        int found = 0;
 
-        for(;;) {
-                if (goal >= rgd->rd_data)
-                        break;
+        while (goal < rgd->rd_data) {
                 down_write(&sdp->sd_log_flush_lock);
                 n = 1;
                 block = rgblk_search(rgd, goal, GFS2_BLKST_UNLINKED,
@@ -990,11 +991,32 @@ static u64 try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked,
                 if (no_addr == skip)
                         continue;
                 *last_unlinked = no_addr;
-                return no_addr;
+
+                error = gfs2_glock_get(sdp, no_addr, &gfs2_inode_glops, CREATE, &gl);
+                if (error)
+                        continue;
+
+                /* If the inode is already in cache, we can ignore it here
+                 * because the existing inode disposal code will deal with
+                 * it when all refs have gone away. Accessing gl_object like
+                 * this is not safe in general. Here it is ok because we do
+                 * not dereference the pointer, and we only need an approx
+                 * answer to whether it is NULL or not.
+                 */
+                ip = gl->gl_object;
+
+                if (ip || queue_work(gfs2_delete_workqueue, &gl->gl_delete) == 0)
+                        gfs2_glock_put(gl);
+                else
+                        found++;
+
+                /* Limit reclaim to sensible number of tasks */
+                if (found > 2*NR_CPUS)
+                        return;
         }
 
         rgd->rd_flags &= ~GFS2_RDF_CHECK;
-        return 0;
+        return;
 }
 
 /**
@@ -1075,11 +1097,9 @@ static void forward_rgrp_set(struct gfs2_sbd *sdp, struct gfs2_rgrpd *rgd)
  * Try to acquire rgrp in way which avoids contending with others.
  *
  * Returns: errno
- *          unlinked: the block address of an unlinked block to be reclaimed
  */
 
-static int get_local_rgrp(struct gfs2_inode *ip, u64 *unlinked,
-                          u64 *last_unlinked)
+static int get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked)
 {
         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
         struct gfs2_rgrpd *rgd, *begin = NULL;
@@ -1089,7 +1109,6 @@ static int get_local_rgrp(struct gfs2_inode *ip, u64 *unlinked,
         int loops = 0;
         int error, rg_locked;
 
-        *unlinked = 0;
         rgd = gfs2_blk2rgrpd(sdp, ip->i_goal);
 
         while (rgd) {
@@ -1106,17 +1125,10 @@ static int get_local_rgrp(struct gfs2_inode *ip, u64 *unlinked,
                 case 0:
                         if (try_rgrp_fit(rgd, al))
                                 goto out;
-                        /* 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)
-                                *unlinked = try_rgrp_unlink(rgd, last_unlinked,
-                                                           ip->i_no_addr);
+                        if (rgd->rd_flags & GFS2_RDF_CHECK)
+                                try_rgrp_unlink(rgd, last_unlinked, ip->i_no_addr);
                         if (!rg_locked)
                                 gfs2_glock_dq_uninit(&al->al_rgd_gh);
-                        if (*unlinked)
-                                return -EAGAIN;
                         /* fall through */
                 case GLR_TRYFAILED:
                         rgd = recent_rgrp_next(rgd);
@@ -1145,13 +1157,10 @@ static int get_local_rgrp(struct gfs2_inode *ip, u64 *unlinked,
                 case 0:
                         if (try_rgrp_fit(rgd, al))
                                 goto out;
-                        if (!rg_locked && rgd->rd_flags & GFS2_RDF_CHECK)
-                                *unlinked = try_rgrp_unlink(rgd, last_unlinked,
-                                                            ip->i_no_addr);
+                        if (rgd->rd_flags & GFS2_RDF_CHECK)
+                                try_rgrp_unlink(rgd, last_unlinked, ip->i_no_addr);
                         if (!rg_locked)
                                 gfs2_glock_dq_uninit(&al->al_rgd_gh);
-                        if (*unlinked)
-                                return -EAGAIN;
                         break;
 
                 case GLR_TRYFAILED:
@@ -1204,12 +1213,12 @@ int gfs2_inplace_reserve_i(struct gfs2_inode *ip, int hold_rindex,
         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
         struct gfs2_alloc *al = ip->i_alloc;
         int error = 0;
-        u64 last_unlinked = NO_BLOCK, unlinked;
+        u64 last_unlinked = NO_BLOCK;
+        int tries = 0;
 
         if (gfs2_assert_warn(sdp, al->al_requested))
                 return -EINVAL;
 
-try_again:
         if (hold_rindex) {
                 /* We need to hold the rindex unless the inode we're using is
                    the rindex itself, in which case it's already held. */
@@ -1218,31 +1227,23 @@ try_again:
                 else if (!sdp->sd_rgrps) /* We may not have the rindex read
                                             in, so: */
                         error = gfs2_ri_update_special(ip);
+                if (error)
+                        return error;
         }
 
-        if (error)
-                return error;
+        do {
+                error = get_local_rgrp(ip, &last_unlinked);
+                /* If there is no space, flushing the log may release some */
+                if (error)
+                        gfs2_log_flush(sdp, NULL);
+        } while (error && tries++ < 3);
 
-        /* Find an rgrp suitable for allocation.  If it encounters any unlinked
-           dinodes along the way, error will equal -EAGAIN and unlinked will
-           contains it block address. We then need to look up that inode and
-           try to free it, and try the allocation again. */
-        error = get_local_rgrp(ip, &unlinked, &last_unlinked);
         if (error) {
                 if (hold_rindex && ip != GFS2_I(sdp->sd_rindex))
                         gfs2_glock_dq_uninit(&al->al_ri_gh);
-                if (error != -EAGAIN)
-                        return error;
-
-                gfs2_process_unlinked_inode(ip->i_inode.i_sb, unlinked);
-                /* regardless of whether or not gfs2_process_unlinked_inode
-                   was successful, we don't want to repeat it again. */
-                last_unlinked = unlinked;
-                gfs2_log_flush(sdp, NULL);
-                error = 0;
-
-                goto try_again;
+                return error;
         }
+
         /* no error, so we have the rgrp set in the inode's allocation. */
         al->al_file = file;
         al->al_line = line;