From a097dc7e24cba7980bc5e2df461a4ef228e97e59 Mon Sep 17 00:00:00 2001
From: Bob Peterson <rpeterso@redhat.com>
Date: Thu, 16 Jul 2015 08:28:04 -0500
Subject: GFS2: Make rgrp reservations part of the gfs2_inode structure

Before this patch, multi-block reservation structures were allocated
from a special slab. This patch folds the structure into the gfs2_inode
structure. The disadvantage is that the gfs2_inode needs more memory,
even when a file is opened read-only. The advantages are: (a) we don't
need the special slab and the extra time it takes to allocate and
deallocate from it. (b) we no longer need to worry that the structure
exists for things like quota management. (c) This also allows us to
remove the calls to get_write_access and put_write_access since we
know the structure will exist.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 8d46ae4..0860f0b 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -787,8 +787,8 @@ static int do_strip(struct gfs2_inode *ip, struct buffer_head *dibh,
 	if (error)
 		goto out_rlist;
 
-	if (gfs2_rs_active(ip->i_res)) /* needs to be done with the rgrp glock held */
-		gfs2_rs_deltree(ip->i_res);
+	if (gfs2_rs_active(&ip->i_res)) /* needs to be done with the rgrp glock held */
+		gfs2_rs_deltree(&ip->i_res);
 
 	error = gfs2_trans_begin(sdp, rg_blocks + RES_DINODE +
 				 RES_INDIRECT + RES_STATFS + RES_QUOTA,
@@ -1291,10 +1291,6 @@ int gfs2_setattr_size(struct inode *inode, u64 newsize)
 	if (ret)
 		return ret;
 
-	ret = get_write_access(inode);
-	if (ret)
-		return ret;
-
 	inode_dio_wait(inode);
 
 	ret = gfs2_rsqa_alloc(ip);
@@ -1307,10 +1303,9 @@ int gfs2_setattr_size(struct inode *inode, u64 newsize)
 		goto out;
 	}
 
-	gfs2_rs_deltree(ip->i_res);
 	ret = do_shrink(inode, oldsize, newsize);
 out:
-	put_write_access(inode);
+	gfs2_rsqa_delete(ip, NULL);
 	return ret;
 }
 
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index de001eb..3ead27d 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -336,8 +336,8 @@ static void gfs2_size_hint(struct file *filep, loff_t offset, size_t size)
 	size_t blks = (size + sdp->sd_sb.sb_bsize - 1) >> sdp->sd_sb.sb_bsize_shift;
 	int hint = min_t(size_t, INT_MAX, blks);
 
-	if (hint > atomic_read(&ip->i_res->rs_sizehint))
-		atomic_set(&ip->i_res->rs_sizehint, hint);
+	if (hint > atomic_read(&ip->i_res.rs_sizehint))
+		atomic_set(&ip->i_res.rs_sizehint, hint);
 }
 
 /**
@@ -397,13 +397,9 @@ static int gfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 	/* Update file times before taking page lock */
 	file_update_time(vma->vm_file);
 
-	ret = get_write_access(inode);
-	if (ret)
-		goto out;
-
 	ret = gfs2_rsqa_alloc(ip);
 	if (ret)
-		goto out_write_access;
+		goto out;
 
 	gfs2_size_hint(vma->vm_file, pos, PAGE_CACHE_SIZE);
 
@@ -486,8 +482,6 @@ out_uninit:
 		set_page_dirty(page);
 		wait_for_stable_page(page);
 	}
-out_write_access:
-	put_write_access(inode);
 out:
 	sb_end_pagefault(inode->i_sb);
 	return block_page_mkwrite_return(ret);
@@ -944,7 +938,8 @@ static long gfs2_fallocate(struct file *file, int mode, loff_t offset, loff_t le
 
 	ret = __gfs2_fallocate(file, mode, offset, len);
 	if (ret)
-		gfs2_rs_deltree(ip->i_res);
+		gfs2_rs_deltree(&ip->i_res);
+
 out_putw:
 	put_write_access(inode);
 out_unlock:
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 6a22f66..25d0f12a 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -394,7 +394,7 @@ struct gfs2_inode {
 	struct gfs2_holder i_iopen_gh;
 	struct gfs2_holder i_gh; /* for prepare/commit_write only */
 	struct gfs2_qadata *i_qadata; /* quota allocation data */
-	struct gfs2_blkreserv *i_res; /* rgrp multi-block reservation */
+	struct gfs2_blkreserv i_res; /* rgrp multi-block reservation */
 	struct gfs2_rgrpd *i_rgd;
 	u64 i_goal;	/* goal block for allocations */
 	struct rw_semaphore i_rw_mutex;
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index c37e6bf..a8ce2e9 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -1859,10 +1859,6 @@ static int setattr_chown(struct inode *inode, struct iattr *attr)
 	if (!(attr->ia_valid & ATTR_GID) || gid_eq(ogid, ngid))
 		ogid = ngid = NO_GID_QUOTA_CHANGE;
 
-	error = get_write_access(inode);
-	if (error)
-		return error;
-
 	error = gfs2_rsqa_alloc(ip);
 	if (error)
 		goto out;
@@ -1903,7 +1899,6 @@ out_end_trans:
 out_gunlock_q:
 	gfs2_quota_unlock(ip);
 out:
-	put_write_access(inode);
 	return error;
 }
 
diff --git a/fs/gfs2/main.c b/fs/gfs2/main.c
index cde5c73..1d709d4 100644
--- a/fs/gfs2/main.c
+++ b/fs/gfs2/main.c
@@ -42,7 +42,8 @@ static void gfs2_init_inode_once(void *foo)
 	init_rwsem(&ip->i_rw_mutex);
 	INIT_LIST_HEAD(&ip->i_trunc_list);
 	ip->i_qadata = NULL;
-	ip->i_res = NULL;
+	memset(&ip->i_res, 0, sizeof(ip->i_res));
+	RB_CLEAR_NODE(&ip->i_res.rs_node);
 	ip->i_hash_cache = NULL;
 }
 
@@ -142,12 +143,6 @@ static int __init init_gfs2_fs(void)
 	if (!gfs2_qadata_cachep)
 		goto fail;
 
-	gfs2_rsrv_cachep = kmem_cache_create("gfs2_mblk",
-					     sizeof(struct gfs2_blkreserv),
-					       0, 0, NULL);
-	if (!gfs2_rsrv_cachep)
-		goto fail;
-
 	register_shrinker(&gfs2_qd_shrinker);
 
 	error = register_filesystem(&gfs2_fs_type);
@@ -200,9 +195,6 @@ fail_lru:
 	unregister_shrinker(&gfs2_qd_shrinker);
 	gfs2_glock_exit();
 
-	if (gfs2_rsrv_cachep)
-		kmem_cache_destroy(gfs2_rsrv_cachep);
-
 	if (gfs2_qadata_cachep)
 		kmem_cache_destroy(gfs2_qadata_cachep);
 
@@ -248,7 +240,6 @@ static void __exit exit_gfs2_fs(void)
 	rcu_barrier();
 
 	mempool_destroy(gfs2_page_pool);
-	kmem_cache_destroy(gfs2_rsrv_cachep);
 	kmem_cache_destroy(gfs2_qadata_cachep);
 	kmem_cache_destroy(gfs2_quotad_cachep);
 	kmem_cache_destroy(gfs2_rgrpd_cachep);
diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index b845efd..63a72109 100644
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -550,10 +550,10 @@ int gfs2_qa_alloc(struct gfs2_inode *ip)
 	return error;
 }
 
-void gfs2_qa_delete(struct gfs2_inode *ip)
+void gfs2_qa_delete(struct gfs2_inode *ip, atomic_t *wcount)
 {
 	down_write(&ip->i_rw_mutex);
-	if (ip->i_qadata) {
+	if (ip->i_qadata && ((wcount == NULL) || (atomic_read(wcount) <= 1))) {
 		kmem_cache_free(gfs2_qadata_cachep, ip->i_qadata);
 		ip->i_qadata = NULL;
 	}
diff --git a/fs/gfs2/quota.h b/fs/gfs2/quota.h
index 1940dd9..5e47c93 100644
--- a/fs/gfs2/quota.h
+++ b/fs/gfs2/quota.h
@@ -19,7 +19,7 @@ struct gfs2_sbd;
 #define NO_GID_QUOTA_CHANGE INVALID_GID
 
 extern int gfs2_qa_alloc(struct gfs2_inode *ip);
-extern void gfs2_qa_delete(struct gfs2_inode *ip);
+extern void gfs2_qa_delete(struct gfs2_inode *ip, atomic_t *wcount);
 extern int gfs2_quota_hold(struct gfs2_inode *ip, kuid_t uid, kgid_t gid);
 extern void gfs2_quota_unhold(struct gfs2_inode *ip);
 
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index cb30748..b879925 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -602,28 +602,7 @@ void gfs2_free_clones(struct gfs2_rgrpd *rgd)
  */
 int gfs2_rsqa_alloc(struct gfs2_inode *ip)
 {
-	int error = 0;
-
-	down_write(&ip->i_rw_mutex);
-	if (ip->i_res)
-		goto out;
-
-	ip->i_res = kmem_cache_zalloc(gfs2_rsrv_cachep, GFP_NOFS);
-	if (!ip->i_res) {
-		error = -ENOMEM;
-		goto out;
-	}
-
-	RB_CLEAR_NODE(&ip->i_res->rs_node);
-	error = gfs2_qa_alloc(ip);
-	if (error) {
-		kmem_cache_free(gfs2_rsrv_cachep, ip->i_res);
-		ip->i_res = NULL;
-	}
-
-out:
-	up_write(&ip->i_rw_mutex);
-	return error;
+	return gfs2_qa_alloc(ip);
 }
 
 static void dump_rs(struct seq_file *seq, const struct gfs2_blkreserv *rs)
@@ -693,15 +672,12 @@ void gfs2_rs_deltree(struct gfs2_blkreserv *rs)
 void gfs2_rsqa_delete(struct gfs2_inode *ip, atomic_t *wcount)
 {
 	down_write(&ip->i_rw_mutex);
-	if (ip->i_res && ((wcount == NULL) || (atomic_read(wcount) <= 1))) {
-		gfs2_rs_deltree(ip->i_res);
-		BUG_ON(ip->i_res->rs_free);
-		kmem_cache_free(gfs2_rsrv_cachep, ip->i_res);
-		ip->i_res = NULL;
-
-		gfs2_qa_delete(ip);
+	if ((wcount == NULL) || (atomic_read(wcount) <= 1)) {
+		gfs2_rs_deltree(&ip->i_res);
+		BUG_ON(ip->i_res.rs_free);
 	}
 	up_write(&ip->i_rw_mutex);
+	gfs2_qa_delete(ip, wcount);
 }
 
 /**
@@ -1465,7 +1441,7 @@ static void rs_insert(struct gfs2_inode *ip)
 {
 	struct rb_node **newn, *parent = NULL;
 	int rc;
-	struct gfs2_blkreserv *rs = ip->i_res;
+	struct gfs2_blkreserv *rs = &ip->i_res;
 	struct gfs2_rgrpd *rgd = rs->rs_rbm.rgd;
 	u64 fsblock = gfs2_rbm_to_block(&rs->rs_rbm);
 
@@ -1512,7 +1488,7 @@ static void rg_mblk_search(struct gfs2_rgrpd *rgd, struct gfs2_inode *ip,
 {
 	struct gfs2_rbm rbm = { .rgd = rgd, };
 	u64 goal;
-	struct gfs2_blkreserv *rs = ip->i_res;
+	struct gfs2_blkreserv *rs = &ip->i_res;
 	u32 extlen;
 	u32 free_blocks = rgd->rd_free_clone - rgd->rd_reserved;
 	int ret;
@@ -1583,7 +1559,7 @@ static u64 gfs2_next_unreserved_block(struct gfs2_rgrpd *rgd, u64 block,
 	}
 
 	if (n) {
-		while ((rs_cmp(block, length, rs) == 0) && (ip->i_res != rs)) {
+		while ((rs_cmp(block, length, rs) == 0) && (&ip->i_res != rs)) {
 			block = gfs2_rbm_to_block(&rs->rs_rbm) + rs->rs_free;
 			n = n->rb_right;
 			if (n == NULL)
@@ -1993,7 +1969,7 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, struct gfs2_alloc_parms *ap)
 {
 	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 	struct gfs2_rgrpd *begin = NULL;
-	struct gfs2_blkreserv *rs = ip->i_res;
+	struct gfs2_blkreserv *rs = &ip->i_res;
 	int error = 0, rg_locked, flags = 0;
 	u64 last_unlinked = NO_BLOCK;
 	int loops = 0;
@@ -2122,7 +2098,7 @@ next_rgrp:
 
 void gfs2_inplace_release(struct gfs2_inode *ip)
 {
-	struct gfs2_blkreserv *rs = ip->i_res;
+	struct gfs2_blkreserv *rs = &ip->i_res;
 
 	if (rs->rs_rgd_gh.gh_gl)
 		gfs2_glock_dq_uninit(&rs->rs_rgd_gh);
@@ -2276,7 +2252,7 @@ static void gfs2_rgrp_error(struct gfs2_rgrpd *rgd)
 static void gfs2_adjust_reservation(struct gfs2_inode *ip,
 				    const struct gfs2_rbm *rbm, unsigned len)
 {
-	struct gfs2_blkreserv *rs = ip->i_res;
+	struct gfs2_blkreserv *rs = &ip->i_res;
 	struct gfs2_rgrpd *rgd = rbm->rgd;
 	unsigned rlen;
 	u64 block;
@@ -2319,8 +2295,8 @@ static void gfs2_set_alloc_start(struct gfs2_rbm *rbm,
 {
 	u64 goal;
 
-	if (gfs2_rs_active(ip->i_res)) {
-		*rbm = ip->i_res->rs_rbm;
+	if (gfs2_rs_active(&ip->i_res)) {
+		*rbm = ip->i_res.rs_rbm;
 		return;
 	}
 
@@ -2374,7 +2350,7 @@ int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *nblocks,
 	gfs2_alloc_extent(&rbm, dinode, nblocks);
 	block = gfs2_rbm_to_block(&rbm);
 	rbm.rgd->rd_last_alloc = block - rbm.rgd->rd_data0;
-	if (gfs2_rs_active(ip->i_res))
+	if (gfs2_rs_active(&ip->i_res))
 		gfs2_adjust_reservation(ip, &rbm, *nblocks);
 	ndata = *nblocks;
 	if (dinode)
diff --git a/fs/gfs2/rgrp.h b/fs/gfs2/rgrp.h
index 06bbefa..66b51cf 100644
--- a/fs/gfs2/rgrp.h
+++ b/fs/gfs2/rgrp.h
@@ -78,7 +78,7 @@ extern int gfs2_rgrp_send_discards(struct gfs2_sbd *sdp, u64 offset,
 extern int gfs2_fitrim(struct file *filp, void __user *argp);
 
 /* This is how to tell if a reservation is in the rgrp tree: */
-static inline bool gfs2_rs_active(struct gfs2_blkreserv *rs)
+static inline bool gfs2_rs_active(const struct gfs2_blkreserv *rs)
 {
 	return rs && !RB_EMPTY_NODE(&rs->rs_node);
 }
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index b030ca2..64f03c8 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -1593,8 +1593,8 @@ out_truncate:
 
 out_unlock:
 	/* Error path for case 1 */
-	if (gfs2_rs_active(ip->i_res))
-		gfs2_rs_deltree(ip->i_res);
+	if (gfs2_rs_active(&ip->i_res))
+		gfs2_rs_deltree(&ip->i_res);
 
 	if (test_bit(HIF_HOLDER, &ip->i_iopen_gh.gh_iflags)) {
 		ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
@@ -1632,7 +1632,8 @@ static struct inode *gfs2_alloc_inode(struct super_block *sb)
 		ip->i_flags = 0;
 		ip->i_gl = NULL;
 		ip->i_rgd = NULL;
-		ip->i_res = NULL;
+		memset(&ip->i_res, 0, sizeof(ip->i_res));
+		RB_CLEAR_NODE(&ip->i_res.rs_node);
 		ip->i_rahead = 0;
 	}
 	return &ip->i_inode;
diff --git a/fs/gfs2/util.c b/fs/gfs2/util.c
index 3b4819d..cf64583 100644
--- a/fs/gfs2/util.c
+++ b/fs/gfs2/util.c
@@ -28,7 +28,6 @@ struct kmem_cache *gfs2_bufdata_cachep __read_mostly;
 struct kmem_cache *gfs2_rgrpd_cachep __read_mostly;
 struct kmem_cache *gfs2_quotad_cachep __read_mostly;
 struct kmem_cache *gfs2_qadata_cachep __read_mostly;
-struct kmem_cache *gfs2_rsrv_cachep __read_mostly;
 mempool_t *gfs2_page_pool __read_mostly;
 
 void gfs2_assert_i(struct gfs2_sbd *sdp)
diff --git a/fs/gfs2/util.h b/fs/gfs2/util.h
index 9edbcc9..c81295f 100644
--- a/fs/gfs2/util.h
+++ b/fs/gfs2/util.h
@@ -150,7 +150,6 @@ extern struct kmem_cache *gfs2_bufdata_cachep;
 extern struct kmem_cache *gfs2_rgrpd_cachep;
 extern struct kmem_cache *gfs2_quotad_cachep;
 extern struct kmem_cache *gfs2_qadata_cachep;
-extern struct kmem_cache *gfs2_rsrv_cachep;
 extern mempool_t *gfs2_page_pool;
 
 static inline unsigned int gfs2_tune_get_i(struct gfs2_tune *gt,
-- 
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