From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file

---
 kernel/fs/ext4/mballoc.c |  592 ++++++++++++++++++++++++++++++++++++++---------------------
 1 files changed, 382 insertions(+), 210 deletions(-)

diff --git a/kernel/fs/ext4/mballoc.c b/kernel/fs/ext4/mballoc.c
index d5ca02a..b35d59d 100644
--- a/kernel/fs/ext4/mballoc.c
+++ b/kernel/fs/ext4/mballoc.c
@@ -16,6 +16,7 @@
 #include <linux/slab.h>
 #include <linux/nospec.h>
 #include <linux/backing-dev.h>
+#include <linux/freezer.h>
 #include <trace/events/ext4.h>
 
 /*
@@ -684,6 +685,8 @@
 	MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments);
 
 	grp = ext4_get_group_info(sb, e4b->bd_group);
+	if (!grp)
+		return NULL;
 	list_for_each(cur, &grp->bb_prealloc_list) {
 		ext4_group_t groupnr;
 		struct ext4_prealloc_space *pa;
@@ -767,9 +770,9 @@
 
 static noinline_for_stack
 void ext4_mb_generate_buddy(struct super_block *sb,
-				void *buddy, void *bitmap, ext4_group_t group)
+			    void *buddy, void *bitmap, ext4_group_t group,
+			    struct ext4_group_info *grp)
 {
-	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
 	ext4_grpblk_t i = 0;
@@ -816,28 +819,8 @@
 	clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
 
 	period = get_cycles() - period;
-	spin_lock(&sbi->s_bal_lock);
-	sbi->s_mb_buddies_generated++;
-	sbi->s_mb_generation_time += period;
-	spin_unlock(&sbi->s_bal_lock);
-}
-
-static void mb_regenerate_buddy(struct ext4_buddy *e4b)
-{
-	int count;
-	int order = 1;
-	void *buddy;
-
-	while ((buddy = mb_find_buddy(e4b, order++, &count))) {
-		ext4_set_bits(buddy, 0, count);
-	}
-	e4b->bd_info->bb_fragments = 0;
-	memset(e4b->bd_info->bb_counters, 0,
-		sizeof(*e4b->bd_info->bb_counters) *
-		(e4b->bd_sb->s_blocksize_bits + 2));
-
-	ext4_mb_generate_buddy(e4b->bd_sb, e4b->bd_buddy,
-		e4b->bd_bitmap, e4b->bd_group);
+	atomic_inc(&sbi->s_mb_buddies_generated);
+	atomic64_add(period, &sbi->s_mb_generation_time);
 }
 
 /* The buddy information is attached the buddy cache inode
@@ -909,6 +892,8 @@
 			break;
 
 		grinfo = ext4_get_group_info(sb, group);
+		if (!grinfo)
+			continue;
 		/*
 		 * If page is uptodate then we came here after online resize
 		 * which added some new uninitialized group info structs, so
@@ -974,6 +959,10 @@
 				group, page->index, i * blocksize);
 			trace_ext4_mb_buddy_bitmap_load(sb, group);
 			grinfo = ext4_get_group_info(sb, group);
+			if (!grinfo) {
+				err = -EFSCORRUPTED;
+				goto out;
+			}
 			grinfo->bb_fragments = 0;
 			memset(grinfo->bb_counters, 0,
 			       sizeof(*grinfo->bb_counters) *
@@ -984,7 +973,7 @@
 			ext4_lock_group(sb, group);
 			/* init the buddy */
 			memset(data, 0xff, blocksize);
-			ext4_mb_generate_buddy(sb, data, incore, group);
+			ext4_mb_generate_buddy(sb, data, incore, group, grinfo);
 			ext4_unlock_group(sb, group);
 			incore = NULL;
 		} else {
@@ -1098,6 +1087,9 @@
 	might_sleep();
 	mb_debug(sb, "init group %u\n", group);
 	this_grp = ext4_get_group_info(sb, group);
+	if (!this_grp)
+		return -EFSCORRUPTED;
+
 	/*
 	 * This ensures that we don't reinit the buddy cache
 	 * page which map to the group from which we are already
@@ -1172,6 +1164,8 @@
 
 	blocks_per_page = PAGE_SIZE / sb->s_blocksize;
 	grp = ext4_get_group_info(sb, group);
+	if (!grp)
+		return -EFSCORRUPTED;
 
 	e4b->bd_blkbits = sb->s_blocksize_bits;
 	e4b->bd_info = grp;
@@ -1512,7 +1506,6 @@
 				sb, e4b->bd_group,
 				EXT4_GROUP_INFO_BBITMAP_CORRUPT);
 		}
-		mb_regenerate_buddy(e4b);
 		goto done;
 	}
 
@@ -1885,7 +1878,9 @@
 	struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
 	struct ext4_free_extent ex;
 
-	if (!(ac->ac_flags & EXT4_MB_HINT_TRY_GOAL))
+	if (!grp)
+		return -EFSCORRUPTED;
+	if (!(ac->ac_flags & (EXT4_MB_HINT_TRY_GOAL | EXT4_MB_HINT_GOAL_ONLY)))
 		return 0;
 	if (grp->bb_free == 0)
 		return 0;
@@ -2109,7 +2104,7 @@
 
 	BUG_ON(cr < 0 || cr >= 4);
 
-	if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
+	if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
 		return false;
 
 	free = grp->bb_free;
@@ -2172,6 +2167,10 @@
 	ext4_grpblk_t free;
 	int ret = 0;
 
+	if (!grp)
+		return -EFSCORRUPTED;
+	if (sbi->s_mb_stats)
+		atomic64_inc(&sbi->s_bal_cX_groups_considered[ac->ac_criteria]);
 	if (should_lock)
 		ext4_lock_group(sb, group);
 	free = grp->bb_free;
@@ -2242,7 +2241,7 @@
 		 * prefetch once, so we avoid getblk() call, which can
 		 * be expensive.
 		 */
-		if (!EXT4_MB_GRP_TEST_AND_SET_READ(grp) &&
+		if (gdp && grp && !EXT4_MB_GRP_TEST_AND_SET_READ(grp) &&
 		    EXT4_MB_GRP_NEED_INIT(grp) &&
 		    ext4_free_group_clusters(sb, gdp) > 0 &&
 		    !(ext4_has_group_desc_csum(sb) &&
@@ -2286,7 +2285,7 @@
 		group--;
 		grp = ext4_get_group_info(sb, group);
 
-		if (EXT4_MB_GRP_NEED_INIT(grp) &&
+		if (grp && gdp && EXT4_MB_GRP_NEED_INIT(grp) &&
 		    ext4_free_group_clusters(sb, gdp) > 0 &&
 		    !(ext4_has_group_desc_csum(sb) &&
 		      (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))) {
@@ -2446,6 +2445,9 @@
 			if (ac->ac_status != AC_STATUS_CONTINUE)
 				break;
 		}
+		/* Processed all groups and haven't found blocks */
+		if (sbi->s_mb_stats && i == ngroups)
+			atomic64_inc(&sbi->s_bal_cX_failed[cr]);
 	}
 
 	if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND &&
@@ -2475,6 +2477,9 @@
 			goto repeat;
 		}
 	}
+
+	if (sbi->s_mb_stats && ac->ac_status == AC_STATUS_FOUND)
+		atomic64_inc(&sbi->s_bal_cX_hits[ac->ac_criteria]);
 out:
 	if (!err && ac->ac_status != AC_STATUS_FOUND && first_err)
 		err = first_err;
@@ -2538,6 +2543,8 @@
 		sizeof(struct ext4_group_info);
 
 	grinfo = ext4_get_group_info(sb, group);
+	if (!grinfo)
+		return 0;
 	/* Load the group info in memory only if not already loaded. */
 	if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) {
 		err = ext4_mb_load_buddy(sb, group, &e4b);
@@ -2548,7 +2555,7 @@
 		buddy_loaded = 1;
 	}
 
-	memcpy(&sg, ext4_get_group_info(sb, group), i);
+	memcpy(&sg, grinfo, i);
 
 	if (buddy_loaded)
 		ext4_mb_unload_buddy(&e4b);
@@ -2573,6 +2580,67 @@
 	.stop   = ext4_mb_seq_groups_stop,
 	.show   = ext4_mb_seq_groups_show,
 };
+
+int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset)
+{
+	struct super_block *sb = (struct super_block *)seq->private;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	seq_puts(seq, "mballoc:\n");
+	if (!sbi->s_mb_stats) {
+		seq_puts(seq, "\tmb stats collection turned off.\n");
+		seq_puts(seq, "\tTo enable, please write \"1\" to sysfs file mb_stats.\n");
+		return 0;
+	}
+	seq_printf(seq, "\treqs: %u\n", atomic_read(&sbi->s_bal_reqs));
+	seq_printf(seq, "\tsuccess: %u\n", atomic_read(&sbi->s_bal_success));
+
+	seq_printf(seq, "\tgroups_scanned: %u\n",  atomic_read(&sbi->s_bal_groups_scanned));
+
+	seq_puts(seq, "\tcr0_stats:\n");
+	seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[0]));
+	seq_printf(seq, "\t\tgroups_considered: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_groups_considered[0]));
+	seq_printf(seq, "\t\tuseless_loops: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_failed[0]));
+
+	seq_puts(seq, "\tcr1_stats:\n");
+	seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[1]));
+	seq_printf(seq, "\t\tgroups_considered: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_groups_considered[1]));
+	seq_printf(seq, "\t\tuseless_loops: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_failed[1]));
+
+	seq_puts(seq, "\tcr2_stats:\n");
+	seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[2]));
+	seq_printf(seq, "\t\tgroups_considered: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_groups_considered[2]));
+	seq_printf(seq, "\t\tuseless_loops: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_failed[2]));
+
+	seq_puts(seq, "\tcr3_stats:\n");
+	seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[3]));
+	seq_printf(seq, "\t\tgroups_considered: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_groups_considered[3]));
+	seq_printf(seq, "\t\tuseless_loops: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_failed[3]));
+	seq_printf(seq, "\textents_scanned: %u\n", atomic_read(&sbi->s_bal_ex_scanned));
+	seq_printf(seq, "\t\tgoal_hits: %u\n", atomic_read(&sbi->s_bal_goals));
+	seq_printf(seq, "\t\t2^n_hits: %u\n", atomic_read(&sbi->s_bal_2orders));
+	seq_printf(seq, "\t\tbreaks: %u\n", atomic_read(&sbi->s_bal_breaks));
+	seq_printf(seq, "\t\tlost: %u\n", atomic_read(&sbi->s_mb_lost_chunks));
+
+	seq_printf(seq, "\tbuddies_generated: %u/%u\n",
+		   atomic_read(&sbi->s_mb_buddies_generated),
+		   ext4_get_groups_count(sb));
+	seq_printf(seq, "\tbuddies_time_used: %llu\n",
+		   atomic64_read(&sbi->s_mb_generation_time));
+	seq_printf(seq, "\tpreallocated: %u\n",
+		   atomic_read(&sbi->s_mb_preallocated));
+	seq_printf(seq, "\tdiscarded: %u\n",
+		   atomic_read(&sbi->s_mb_discarded));
+	return 0;
+}
 
 static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)
 {
@@ -2764,8 +2832,12 @@
 
 err_freebuddy:
 	cachep = get_groupinfo_cache(sb->s_blocksize_bits);
-	while (i-- > 0)
-		kmem_cache_free(cachep, ext4_get_group_info(sb, i));
+	while (i-- > 0) {
+		struct ext4_group_info *grp = ext4_get_group_info(sb, i);
+
+		if (grp)
+			kmem_cache_free(cachep, grp);
+	}
 	i = sbi->s_group_info_size;
 	rcu_read_lock();
 	group_info = rcu_dereference(sbi->s_group_info);
@@ -2874,7 +2946,6 @@
 	} while (i <= sb->s_blocksize_bits + 1);
 
 	spin_lock_init(&sbi->s_md_lock);
-	spin_lock_init(&sbi->s_bal_lock);
 	sbi->s_mb_free_pending = 0;
 	INIT_LIST_HEAD(&sbi->s_freed_data_list);
 
@@ -2973,6 +3044,8 @@
 		for (i = 0; i < ngroups; i++) {
 			cond_resched();
 			grinfo = ext4_get_group_info(sb, i);
+			if (!grinfo)
+				continue;
 			mb_group_bb_bitmap_free(grinfo);
 			ext4_lock_group(sb, i);
 			count = ext4_mb_cleanup_pa(grinfo);
@@ -3002,17 +3075,18 @@
 				atomic_read(&sbi->s_bal_reqs),
 				atomic_read(&sbi->s_bal_success));
 		ext4_msg(sb, KERN_INFO,
-		      "mballoc: %u extents scanned, %u goal hits, "
+		      "mballoc: %u extents scanned, %u groups scanned, %u goal hits, "
 				"%u 2^N hits, %u breaks, %u lost",
 				atomic_read(&sbi->s_bal_ex_scanned),
+				atomic_read(&sbi->s_bal_groups_scanned),
 				atomic_read(&sbi->s_bal_goals),
 				atomic_read(&sbi->s_bal_2orders),
 				atomic_read(&sbi->s_bal_breaks),
 				atomic_read(&sbi->s_mb_lost_chunks));
 		ext4_msg(sb, KERN_INFO,
-		       "mballoc: %lu generated and it took %Lu",
-				sbi->s_mb_buddies_generated,
-				sbi->s_mb_generation_time);
+		       "mballoc: %u generated and it took %llu",
+				atomic_read(&sbi->s_mb_buddies_generated),
+				atomic64_read(&sbi->s_mb_generation_time));
 		ext4_msg(sb, KERN_INFO,
 		       "mballoc: %u preallocated, %u discarded",
 				atomic_read(&sbi->s_mb_preallocated),
@@ -3439,6 +3513,7 @@
 				struct ext4_allocation_request *ar)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+	struct ext4_super_block *es = sbi->s_es;
 	int bsbits, max;
 	ext4_lblk_t end;
 	loff_t size, start_off;
@@ -3619,18 +3694,21 @@
 	ac->ac_g_ex.fe_len = EXT4_NUM_B2C(sbi, size);
 
 	/* define goal start in order to merge */
-	if (ar->pright && (ar->lright == (start + size))) {
+	if (ar->pright && (ar->lright == (start + size)) &&
+	    ar->pright >= size &&
+	    ar->pright - size >= le32_to_cpu(es->s_first_data_block)) {
 		/* merge to the right */
 		ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size,
-						&ac->ac_f_ex.fe_group,
-						&ac->ac_f_ex.fe_start);
+						&ac->ac_g_ex.fe_group,
+						&ac->ac_g_ex.fe_start);
 		ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
 	}
-	if (ar->pleft && (ar->lleft + 1 == start)) {
+	if (ar->pleft && (ar->lleft + 1 == start) &&
+	    ar->pleft + 1 < ext4_blocks_count(es)) {
 		/* merge to the left */
 		ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1,
-						&ac->ac_f_ex.fe_group,
-						&ac->ac_f_ex.fe_start);
+						&ac->ac_g_ex.fe_group,
+						&ac->ac_g_ex.fe_start);
 		ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
 	}
 
@@ -3642,12 +3720,13 @@
 {
 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
 
-	if (sbi->s_mb_stats && ac->ac_g_ex.fe_len > 1) {
+	if (sbi->s_mb_stats && ac->ac_g_ex.fe_len >= 1) {
 		atomic_inc(&sbi->s_bal_reqs);
 		atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated);
 		if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len)
 			atomic_inc(&sbi->s_bal_success);
 		atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned);
+		atomic_add(ac->ac_groups_scanned, &sbi->s_bal_groups_scanned);
 		if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
 				ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
 			atomic_inc(&sbi->s_bal_goals);
@@ -3722,6 +3801,7 @@
 	BUG_ON(start < pa->pa_pstart);
 	BUG_ON(end > pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len));
 	BUG_ON(pa->pa_free < len);
+	BUG_ON(ac->ac_b_ex.fe_len <= 0);
 	pa->pa_free -= len;
 
 	mb_debug(ac->ac_sb, "use %llu/%d from inode pa %p\n", start, len, pa);
@@ -3884,6 +3964,8 @@
 	struct ext4_free_data *entry;
 
 	grp = ext4_get_group_info(sb, group);
+	if (!grp)
+		return;
 	n = rb_first(&(grp->bb_free_root));
 
 	while (n) {
@@ -3910,6 +3992,9 @@
 	ext4_grpblk_t start;
 	int preallocated = 0;
 	int len;
+
+	if (!grp)
+		return;
 
 	/* all form of preallocation discards first load group,
 	 * so the only competing code is preallocation use.
@@ -4046,10 +4131,8 @@
 	pa = ac->ac_pa;
 
 	if (ac->ac_b_ex.fe_len < ac->ac_g_ex.fe_len) {
-		int winl;
-		int wins;
-		int win;
-		int offs;
+		int new_bex_start;
+		int new_bex_end;
 
 		/* we can't allocate as much as normalizer wants.
 		 * so, found space must get proper lstart
@@ -4057,26 +4140,40 @@
 		BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
 		BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);
 
-		/* we're limited by original request in that
-		 * logical block must be covered any way
-		 * winl is window we can move our chunk within */
-		winl = ac->ac_o_ex.fe_logical - ac->ac_g_ex.fe_logical;
+		/*
+		 * Use the below logic for adjusting best extent as it keeps
+		 * fragmentation in check while ensuring logical range of best
+		 * extent doesn't overflow out of goal extent:
+		 *
+		 * 1. Check if best ex can be kept at end of goal and still
+		 *    cover original start
+		 * 2. Else, check if best ex can be kept at start of goal and
+		 *    still cover original start
+		 * 3. Else, keep the best ex at start of original request.
+		 */
+		new_bex_end = ac->ac_g_ex.fe_logical +
+			EXT4_C2B(sbi, ac->ac_g_ex.fe_len);
+		new_bex_start = new_bex_end - EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
+		if (ac->ac_o_ex.fe_logical >= new_bex_start)
+			goto adjust_bex;
 
-		/* also, we should cover whole original request */
-		wins = EXT4_C2B(sbi, ac->ac_b_ex.fe_len - ac->ac_o_ex.fe_len);
+		new_bex_start = ac->ac_g_ex.fe_logical;
+		new_bex_end =
+			new_bex_start + EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
+		if (ac->ac_o_ex.fe_logical < new_bex_end)
+			goto adjust_bex;
 
-		/* the smallest one defines real window */
-		win = min(winl, wins);
+		new_bex_start = ac->ac_o_ex.fe_logical;
+		new_bex_end =
+			new_bex_start + EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
 
-		offs = ac->ac_o_ex.fe_logical %
-			EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
-		if (offs && offs < win)
-			win = offs;
+adjust_bex:
+		ac->ac_b_ex.fe_logical = new_bex_start;
 
-		ac->ac_b_ex.fe_logical = ac->ac_o_ex.fe_logical -
-			EXT4_NUM_B2C(sbi, win);
 		BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
 		BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
+		BUG_ON(new_bex_end > (ac->ac_g_ex.fe_logical +
+				      EXT4_C2B(sbi, ac->ac_g_ex.fe_len)));
 	}
 
 	/* preallocation can change ac_b_ex, thus we store actually
@@ -4102,6 +4199,8 @@
 
 	ei = EXT4_I(ac->ac_inode);
 	grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
+	if (!grp)
+		return;
 
 	pa->pa_obj_lock = &ei->i_prealloc_lock;
 	pa->pa_inode = ac->ac_inode;
@@ -4155,6 +4254,8 @@
 	atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
 
 	grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
+	if (!grp)
+		return;
 	lg = ac->ac_lg;
 	BUG_ON(lg == NULL);
 
@@ -4250,7 +4351,11 @@
 	trace_ext4_mb_release_group_pa(sb, pa);
 	BUG_ON(pa->pa_deleted == 0);
 	ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
-	BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
+	if (unlikely(group != e4b->bd_group && pa->pa_len != 0)) {
+		ext4_warning(sb, "bad group: expected %u, group %u, pa_start %llu",
+			     e4b->bd_group, group, pa->pa_pstart);
+		return 0;
+	}
 	mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
 	atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded);
 	trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len);
@@ -4279,6 +4384,8 @@
 	int err;
 	int free = 0;
 
+	if (!grp)
+		return 0;
 	mb_debug(sb, "discard preallocation for group %u\n", group);
 	if (list_empty(&grp->bb_prealloc_list))
 		goto out_dbg;
@@ -4516,6 +4623,9 @@
 		struct ext4_prealloc_space *pa;
 		ext4_grpblk_t start;
 		struct list_head *cur;
+
+		if (!grp)
+			continue;
 		ext4_lock_group(sb, i);
 		list_for_each(cur, &grp->bb_prealloc_list) {
 			pa = list_entry(cur, struct ext4_prealloc_space,
@@ -5303,7 +5413,8 @@
 }
 
 /**
- * ext4_free_blocks() -- Free given blocks and update quota
+ * ext4_mb_clear_bb() -- helper function for freeing blocks.
+ *			Used by ext4_free_blocks()
  * @handle:		handle for this transaction
  * @inode:		inode
  * @bh:			optional buffer of the block to be freed
@@ -5311,13 +5422,14 @@
  * @count:		number of blocks to be freed
  * @flags:		flags used by ext4_free_blocks
  */
-void ext4_free_blocks(handle_t *handle, struct inode *inode,
-		      struct buffer_head *bh, ext4_fsblk_t block,
-		      unsigned long count, int flags)
+static void ext4_mb_clear_bb(handle_t *handle, struct inode *inode,
+			       ext4_fsblk_t block, unsigned long count,
+			       int flags)
 {
 	struct buffer_head *bitmap_bh = NULL;
 	struct super_block *sb = inode->i_sb;
 	struct ext4_group_desc *gdp;
+	struct ext4_group_info *grp;
 	unsigned int overflow;
 	ext4_grpblk_t bit;
 	struct buffer_head *gd_bh;
@@ -5330,86 +5442,21 @@
 
 	sbi = EXT4_SB(sb);
 
-	if (sbi->s_mount_state & EXT4_FC_REPLAY) {
-		ext4_free_blocks_simple(inode, block, count);
-		return;
-	}
-
-	might_sleep();
-	if (bh) {
-		if (block)
-			BUG_ON(block != bh->b_blocknr);
-		else
-			block = bh->b_blocknr;
-	}
-
 	if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
 	    !ext4_inode_block_valid(inode, block, count)) {
-		ext4_error(sb, "Freeing blocks not in datazone - "
-			   "block = %llu, count = %lu", block, count);
+		ext4_error(sb, "Freeing blocks in system zone - "
+			   "Block = %llu, count = %lu", block, count);
+		/* err = 0. ext4_std_error should be a no op */
 		goto error_return;
 	}
-
-	ext4_debug("freeing block %llu\n", block);
-	trace_ext4_free_blocks(inode, block, count, flags);
-
-	if (bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
-		BUG_ON(count > 1);
-
-		ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
-			    inode, bh, block);
-	}
-
-	/*
-	 * If the extent to be freed does not begin on a cluster
-	 * boundary, we need to deal with partial clusters at the
-	 * beginning and end of the extent.  Normally we will free
-	 * blocks at the beginning or the end unless we are explicitly
-	 * requested to avoid doing so.
-	 */
-	overflow = EXT4_PBLK_COFF(sbi, block);
-	if (overflow) {
-		if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) {
-			overflow = sbi->s_cluster_ratio - overflow;
-			block += overflow;
-			if (count > overflow)
-				count -= overflow;
-			else
-				return;
-		} else {
-			block -= overflow;
-			count += overflow;
-		}
-	}
-	overflow = EXT4_LBLK_COFF(sbi, count);
-	if (overflow) {
-		if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) {
-			if (count > overflow)
-				count -= overflow;
-			else
-				return;
-		} else
-			count += sbi->s_cluster_ratio - overflow;
-	}
-
-	if (!bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
-		int i;
-		int is_metadata = flags & EXT4_FREE_BLOCKS_METADATA;
-
-		for (i = 0; i < count; i++) {
-			cond_resched();
-			if (is_metadata)
-				bh = sb_find_get_block(inode->i_sb, block + i);
-			ext4_forget(handle, is_metadata, inode, bh, block + i);
-		}
-	}
+	flags |= EXT4_FREE_BLOCKS_VALIDATED;
 
 do_more:
 	overflow = 0;
 	ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
 
-	if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(
-			ext4_get_group_info(sb, block_group))))
+	grp = ext4_get_group_info(sb, block_group);
+	if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
 		return;
 
 	/*
@@ -5420,6 +5467,8 @@
 		overflow = EXT4_C2B(sbi, bit) + count -
 			EXT4_BLOCKS_PER_GROUP(sb);
 		count -= overflow;
+		/* The range changed so it's no longer validated */
+		flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
 	}
 	count_clusters = EXT4_NUM_B2C(sbi, count);
 	bitmap_bh = ext4_read_block_bitmap(sb, block_group);
@@ -5434,13 +5483,8 @@
 		goto error_return;
 	}
 
-	if (in_range(ext4_block_bitmap(sb, gdp), block, count) ||
-	    in_range(ext4_inode_bitmap(sb, gdp), block, count) ||
-	    in_range(block, ext4_inode_table(sb, gdp),
-		     sbi->s_itb_per_group) ||
-	    in_range(block + count - 1, ext4_inode_table(sb, gdp),
-		     sbi->s_itb_per_group)) {
-
+	if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
+	    !ext4_inode_block_valid(inode, block, count)) {
 		ext4_error(sb, "Freeing blocks in system zone - "
 			   "Block = %llu, count = %lu", block, count);
 		/* err = 0. ext4_std_error should be a no op */
@@ -5506,11 +5550,11 @@
 		 * them with group lock_held
 		 */
 		if (test_opt(sb, DISCARD)) {
-			err = ext4_issue_discard(sb, block_group, bit, count,
-						 NULL);
+			err = ext4_issue_discard(sb, block_group, bit,
+						 count_clusters, NULL);
 			if (err && err != -EOPNOTSUPP)
 				ext4_msg(sb, KERN_WARNING, "discard request in"
-					 " group:%d block:%d count:%lu failed"
+					 " group:%u block:%d count:%lu failed"
 					 " with %d", block_group, bit, count,
 					 err);
 		} else
@@ -5562,11 +5606,116 @@
 		block += count;
 		count = overflow;
 		put_bh(bitmap_bh);
+		/* The range changed so it's no longer validated */
+		flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
 		goto do_more;
 	}
 error_return:
 	brelse(bitmap_bh);
 	ext4_std_error(sb, err);
+	return;
+}
+
+/**
+ * ext4_free_blocks() -- Free given blocks and update quota
+ * @handle:		handle for this transaction
+ * @inode:		inode
+ * @bh:			optional buffer of the block to be freed
+ * @block:		starting physical block to be freed
+ * @count:		number of blocks to be freed
+ * @flags:		flags used by ext4_free_blocks
+ */
+void ext4_free_blocks(handle_t *handle, struct inode *inode,
+		      struct buffer_head *bh, ext4_fsblk_t block,
+		      unsigned long count, int flags)
+{
+	struct super_block *sb = inode->i_sb;
+	unsigned int overflow;
+	struct ext4_sb_info *sbi;
+
+	sbi = EXT4_SB(sb);
+
+	if (bh) {
+		if (block)
+			BUG_ON(block != bh->b_blocknr);
+		else
+			block = bh->b_blocknr;
+	}
+
+	if (sbi->s_mount_state & EXT4_FC_REPLAY) {
+		ext4_free_blocks_simple(inode, block, EXT4_NUM_B2C(sbi, count));
+		return;
+	}
+
+	might_sleep();
+
+	if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
+	    !ext4_inode_block_valid(inode, block, count)) {
+		ext4_error(sb, "Freeing blocks not in datazone - "
+			   "block = %llu, count = %lu", block, count);
+		return;
+	}
+	flags |= EXT4_FREE_BLOCKS_VALIDATED;
+
+	ext4_debug("freeing block %llu\n", block);
+	trace_ext4_free_blocks(inode, block, count, flags);
+
+	if (bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
+		BUG_ON(count > 1);
+
+		ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
+			    inode, bh, block);
+	}
+
+	/*
+	 * If the extent to be freed does not begin on a cluster
+	 * boundary, we need to deal with partial clusters at the
+	 * beginning and end of the extent.  Normally we will free
+	 * blocks at the beginning or the end unless we are explicitly
+	 * requested to avoid doing so.
+	 */
+	overflow = EXT4_PBLK_COFF(sbi, block);
+	if (overflow) {
+		if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) {
+			overflow = sbi->s_cluster_ratio - overflow;
+			block += overflow;
+			if (count > overflow)
+				count -= overflow;
+			else
+				return;
+		} else {
+			block -= overflow;
+			count += overflow;
+		}
+		/* The range changed so it's no longer validated */
+		flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
+	}
+	overflow = EXT4_LBLK_COFF(sbi, count);
+	if (overflow) {
+		if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) {
+			if (count > overflow)
+				count -= overflow;
+			else
+				return;
+		} else
+			count += sbi->s_cluster_ratio - overflow;
+		/* The range changed so it's no longer validated */
+		flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
+	}
+
+	if (!bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
+		int i;
+		int is_metadata = flags & EXT4_FREE_BLOCKS_METADATA;
+
+		for (i = 0; i < count; i++) {
+			cond_resched();
+			if (is_metadata)
+				bh = sb_find_get_block(inode->i_sb, block + i);
+			ext4_forget(handle, is_metadata, inode, bh, block + i);
+		}
+	}
+
+	ext4_mb_clear_bb(handle, inode, block, count, flags);
 	return;
 }
 
@@ -5626,11 +5775,7 @@
 		goto error_return;
 	}
 
-	if (in_range(ext4_block_bitmap(sb, desc), block, count) ||
-	    in_range(ext4_inode_bitmap(sb, desc), block, count) ||
-	    in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) ||
-	    in_range(block + count - 1, ext4_inode_table(sb, desc),
-		     sbi->s_itb_per_group)) {
+	if (!ext4_sb_block_valid(sb, NULL, block, count)) {
 		ext4_error(sb, "Adding blocks in system zones - "
 			   "Block = %llu, count = %lu",
 			   block, count);
@@ -5715,19 +5860,19 @@
  * @sb:		super block for the file system
  * @start:	starting block of the free extent in the alloc. group
  * @count:	number of blocks to TRIM
- * @group:	alloc. group we are working with
  * @e4b:	ext4 buddy for the group
  *
  * Trim "count" blocks starting at "start" in the "group". To assure that no
  * one will allocate those blocks, mark it as used in buddy bitmap. This must
  * be called with under the group lock.
  */
-static int ext4_trim_extent(struct super_block *sb, int start, int count,
-			     ext4_group_t group, struct ext4_buddy *e4b)
+static int ext4_trim_extent(struct super_block *sb,
+		int start, int count, struct ext4_buddy *e4b)
 __releases(bitlock)
 __acquires(bitlock)
 {
 	struct ext4_free_extent ex;
+	ext4_group_t group = e4b->bd_group;
 	int ret = 0;
 
 	trace_ext4_trim_extent(sb, group, start, count);
@@ -5748,6 +5893,71 @@
 	ext4_lock_group(sb, group);
 	mb_free_blocks(NULL, e4b, start, ex.fe_len);
 	return ret;
+}
+
+static ext4_grpblk_t ext4_last_grp_cluster(struct super_block *sb,
+					   ext4_group_t grp)
+{
+	if (grp < ext4_get_groups_count(sb))
+		return EXT4_CLUSTERS_PER_GROUP(sb) - 1;
+	return (ext4_blocks_count(EXT4_SB(sb)->s_es) -
+		ext4_group_first_block_no(sb, grp) - 1) >>
+					EXT4_CLUSTER_BITS(sb);
+}
+
+static bool ext4_trim_interrupted(void)
+{
+	return fatal_signal_pending(current) || freezing(current);
+}
+
+static int ext4_try_to_trim_range(struct super_block *sb,
+		struct ext4_buddy *e4b, ext4_grpblk_t start,
+		ext4_grpblk_t max, ext4_grpblk_t minblocks)
+{
+	ext4_grpblk_t next, count, free_count;
+	bool set_trimmed = false;
+	void *bitmap;
+
+	bitmap = e4b->bd_bitmap;
+	if (start == 0 && max >= ext4_last_grp_cluster(sb, e4b->bd_group))
+		set_trimmed = true;
+	start = max(e4b->bd_info->bb_first_free, start);
+	count = 0;
+	free_count = 0;
+
+	while (start <= max) {
+		start = mb_find_next_zero_bit(bitmap, max + 1, start);
+		if (start > max)
+			break;
+		next = mb_find_next_bit(bitmap, max + 1, start);
+
+		if ((next - start) >= minblocks) {
+			int ret = ext4_trim_extent(sb, start, next - start, e4b);
+
+			if (ret && ret != -EOPNOTSUPP)
+				return count;
+			count += next - start;
+		}
+		free_count += next - start;
+		start = next + 1;
+
+		if (ext4_trim_interrupted())
+			return count;
+
+		if (need_resched()) {
+			ext4_unlock_group(sb, e4b->bd_group);
+			cond_resched();
+			ext4_lock_group(sb, e4b->bd_group);
+		}
+
+		if ((e4b->bd_info->bb_free - free_count) < minblocks)
+			break;
+	}
+
+	if (set_trimmed)
+		EXT4_MB_GRP_SET_TRIMMED(e4b->bd_info);
+
+	return count;
 }
 
 /**
@@ -5773,10 +5983,8 @@
 		   ext4_grpblk_t start, ext4_grpblk_t max,
 		   ext4_grpblk_t minblocks)
 {
-	void *bitmap;
-	ext4_grpblk_t next, count = 0, free_count = 0;
 	struct ext4_buddy e4b;
-	int ret = 0;
+	int ret;
 
 	trace_ext4_trim_all_free(sb, group, start, max);
 
@@ -5786,58 +5994,20 @@
 			     ret, group);
 		return ret;
 	}
-	bitmap = e4b.bd_bitmap;
 
 	ext4_lock_group(sb, group);
-	if (EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) &&
-	    minblocks >= atomic_read(&EXT4_SB(sb)->s_last_trim_minblks))
-		goto out;
 
-	start = (e4b.bd_info->bb_first_free > start) ?
-		e4b.bd_info->bb_first_free : start;
+	if (!EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) ||
+	    minblocks < EXT4_SB(sb)->s_last_trim_minblks)
+		ret = ext4_try_to_trim_range(sb, &e4b, start, max, minblocks);
+	else
+		ret = 0;
 
-	while (start <= max) {
-		start = mb_find_next_zero_bit(bitmap, max + 1, start);
-		if (start > max)
-			break;
-		next = mb_find_next_bit(bitmap, max + 1, start);
-
-		if ((next - start) >= minblocks) {
-			ret = ext4_trim_extent(sb, start,
-					       next - start, group, &e4b);
-			if (ret && ret != -EOPNOTSUPP)
-				break;
-			ret = 0;
-			count += next - start;
-		}
-		free_count += next - start;
-		start = next + 1;
-
-		if (fatal_signal_pending(current)) {
-			count = -ERESTARTSYS;
-			break;
-		}
-
-		if (need_resched()) {
-			ext4_unlock_group(sb, group);
-			cond_resched();
-			ext4_lock_group(sb, group);
-		}
-
-		if ((e4b.bd_info->bb_free - free_count) < minblocks)
-			break;
-	}
-
-	if (!ret) {
-		ret = count;
-		EXT4_MB_GRP_SET_TRIMMED(e4b.bd_info);
-	}
-out:
 	ext4_unlock_group(sb, group);
 	ext4_mb_unload_buddy(&e4b);
 
 	ext4_debug("trimmed %d blocks in the group %d\n",
-		count, group);
+		ret, group);
 
 	return ret;
 }
@@ -5882,7 +6052,7 @@
 		if (minlen > EXT4_CLUSTERS_PER_GROUP(sb))
 			goto out;
 	}
-	if (end >= max_blks)
+	if (end >= max_blks - 1)
 		end = max_blks - 1;
 	if (end <= first_data_blk)
 		goto out;
@@ -5899,7 +6069,11 @@
 	end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
 
 	for (group = first_group; group <= last_group; group++) {
+		if (ext4_trim_interrupted())
+			break;
 		grp = ext4_get_group_info(sb, group);
+		if (!grp)
+			continue;
 		/* We only do this if the grp has never been initialized */
 		if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
 			ret = ext4_mb_init_group(sb, group, GFP_NOFS);
@@ -5915,10 +6089,9 @@
 		 */
 		if (group == last_group)
 			end = last_cluster;
-
 		if (grp->bb_free >= minlen) {
 			cnt = ext4_trim_all_free(sb, group, first_cluster,
-						end, minlen);
+						 end, minlen);
 			if (cnt < 0) {
 				ret = cnt;
 				break;
@@ -5934,7 +6107,7 @@
 	}
 
 	if (!ret)
-		atomic_set(&EXT4_SB(sb)->s_last_trim_minblks, minlen);
+		EXT4_SB(sb)->s_last_trim_minblks = minlen;
 
 out:
 	range->len = EXT4_C2B(EXT4_SB(sb), trimmed) << sb->s_blocksize_bits;
@@ -5963,8 +6136,7 @@
 
 	ext4_lock_group(sb, group);
 
-	start = (e4b.bd_info->bb_first_free > start) ?
-		e4b.bd_info->bb_first_free : start;
+	start = max(e4b.bd_info->bb_first_free, start);
 	if (end >= EXT4_CLUSTERS_PER_GROUP(sb))
 		end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
 

--
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