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FAILED: patch "[PATCH] f2fs: accurately adjust free_sections during" failed to apply to 6.18-stable tree

PATCH New [email protected] 2 participants 2 messages Sep 9 – Sep 12

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author maintainer
#0 lore raw

The patch below does not apply to the 6.18-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x 8c963d1738fdca400082ff5f9d99e083de4f4e70
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026090936-harmonica-dagger-40f3@gregkh' --subject-prefix 'PATCH 6.18.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8c963d1738fdca400082ff5f9d99e083de4f4e70 Mon Sep 17 00:00:00 2001
From: Daeho Jeong <[email protected]>
Date: Mon, 24 Aug 2026 18:53:03 -0700
Subject: [PATCH] f2fs: accurately adjust free_sections during
free_segment_range

In free_segment_range(), MAIN_SECS(sbi) is temporarily reduced by secs to restrict block allocation to the safe remaining main area while valid blocks in the truncated range are evacuated by GC.

However, FREE_I(sbi)->free_sections tracks the total number of free sections across the whole filesystem. If any sections within the truncated range were already free upon entering free_segment_range(), failing to deduct them from free_sections causes the filesystem to overestimate available free sections in the active, reduced main area. This leads to inconsistent free section accounting during GC data migration and can trigger unexpected allocation failures or assertion errors when space is tight.

Fix this by calculating the number of already-free sections in the truncated range, deducting them from free_sections upon entering free_segment_range(), and restoring them on exit.

Fixes b4b10061ef98 ("f2fs: refactor resize_fs to avoid meta updates in progress")
fs/f2fs/gc.c +14 -1
index 0c17038fcfd7..0a00180c21dc 100644
@@ -2231,17 +2231,27 @@ void f2fs_reset_gc_victim_resource(struct f2fs_sb_info *sbi,
 static int free_segment_range(struct f2fs_sb_info *sbi,
 				unsigned int secs, bool dry_run)
 {
-	unsigned int next_inuse, start, end;
+	unsigned int secno, next_inuse, start, end, end_secno;
 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
+	unsigned int freed_secs = 0;
 	int err = 0;
 	int type;
 
 	MAIN_SECS(sbi) -= secs;
 	start = MAIN_SECS(sbi) * SEGS_PER_SEC(sbi);
 	end = MAIN_SEGS(sbi) - 1;
+	end_secno = GET_SEC_FROM_SEG(sbi, end);
 
 	f2fs_reset_gc_victim_resource(sbi, start, end);
 
+	spin_lock(&FREE_I(sbi)->segmap_lock);
+	for (secno = MAIN_SECS(sbi); secno <= end_secno; secno++) {
+		if (!test_bit(secno, FREE_I(sbi)->free_secmap))
+			freed_secs++;
+	}
+	FREE_I(sbi)->free_sections -= freed_secs;
+	spin_unlock(&FREE_I(sbi)->segmap_lock);
+
 	/* Move out cursegs from the target range */
 	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_TYPE; type++) {
 		err = f2fs_allocate_segment_for_resize(sbi, type, start, end);
@@ -2266,6 +2276,9 @@ static int free_segment_range(struct f2fs_sb_info *sbi,
 		f2fs_bug_on(sbi, 1);
 	}
 out:
+	spin_lock(&FREE_I(sbi)->segmap_lock);
+	FREE_I(sbi)->free_sections += freed_secs;
+	spin_unlock(&FREE_I(sbi)->segmap_lock);
 	MAIN_SECS(sbi) += secs;
 	return err;
 }
maintainer
#1 lore raw

PATCH 1/1 f2fs: accurately adjust free_sections during free_segment_range

From: Daeho Jeong <[email protected]>

[ Upstream commit 8c963d1738fdca400082ff5f9d99e083de4f4e70 ]

In free_segment_range(), MAIN_SECS(sbi) is temporarily reduced by secs to restrict block allocation to the safe remaining main area while valid blocks in the truncated range are evacuated by GC.

However, FREE_I(sbi)->free_sections tracks the total number of free sections across the whole filesystem. If any sections within the truncated range were already free upon entering free_segment_range(), failing to deduct them from free_sections causes the filesystem to overestimate available free sections in the active, reduced main area. This leads to inconsistent free section accounting during GC data migration and can trigger unexpected allocation failures or assertion errors when space is tight.

Fix this by calculating the number of already-free sections in the truncated range, deducting them from free_sections upon entering free_segment_range(), and restoring them on exit.

Fixes b4b10061ef98 ("f2fs: refactor resize_fs to avoid meta updates in progress")
[ retained gc_mode and gc_type declarations needed by the older inline GC reset logic. ]
---
 fs/f2fs/gc.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)
fs/f2fs/gc.c +14 -1
index 429fc5bd4ae0d..268a31ec87c81 100644
@@ -2170,8 +2170,9 @@ int f2fs_gc_range(struct f2fs_sb_info *sbi,
 static int free_segment_range(struct f2fs_sb_info *sbi,
 				unsigned int secs, bool dry_run)
 {
-	unsigned int next_inuse, start, end;
+	unsigned int secno, next_inuse, start, end, end_secno;
 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
+	unsigned int freed_secs = 0;
 	int gc_mode, gc_type;
 	int err = 0;
 	int type;
@@ -2180,6 +2181,7 @@ static int free_segment_range(struct f2fs_sb_info *sbi,
 	MAIN_SECS(sbi) -= secs;
 	start = MAIN_SECS(sbi) * SEGS_PER_SEC(sbi);
 	end = MAIN_SEGS(sbi) - 1;
+	end_secno = GET_SEC_FROM_SEG(sbi, end);
 
 	mutex_lock(&DIRTY_I(sbi)->seglist_lock);
 	for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
@@ -2191,6 +2193,14 @@ static int free_segment_range(struct f2fs_sb_info *sbi,
 			sbi->next_victim_seg[gc_type] = NULL_SEGNO;
 	mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
 
+	spin_lock(&FREE_I(sbi)->segmap_lock);
+	for (secno = MAIN_SECS(sbi); secno <= end_secno; secno++) {
+		if (!test_bit(secno, FREE_I(sbi)->free_secmap))
+			freed_secs++;
+	}
+	FREE_I(sbi)->free_sections -= freed_secs;
+	spin_unlock(&FREE_I(sbi)->segmap_lock);
+
 	/* Move out cursegs from the target range */
 	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_TYPE; type++) {
 		err = f2fs_allocate_segment_for_resize(sbi, type, start, end);
@@ -2215,6 +2225,9 @@ static int free_segment_range(struct f2fs_sb_info *sbi,
 		f2fs_bug_on(sbi, 1);
 	}
 out:
+	spin_lock(&FREE_I(sbi)->segmap_lock);
+	FREE_I(sbi)->free_sections += freed_secs;
+	spin_unlock(&FREE_I(sbi)->segmap_lock);
 	MAIN_SECS(sbi) += secs;
 	return err;
 }
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