FAILED: patch "[PATCH] f2fs: don't over-report free space or inodes in statvfs" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-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-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x a9201960623287927bf5776de3f70fb2fbde7e02
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025062052-outpost-creasing-1ef3@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From a9201960623287927bf5776de3f70fb2fbde7e02 Mon Sep 17 00:00:00 2001
From: Chao Yu <[email protected]>
Date: Tue, 13 May 2025 19:25:38 +0800
Subject: [PATCH] f2fs: don't over-report free space or inodes in statvfs

This fixes an analogus bug that was fixed in modern filesystems:
a) xfs in commit 4b8d867ca6e2 ("xfs: don't over-report free space or inodes in statvfs")
b) ext4 in commit f87d3af74193 ("ext4: don't over-report free space or inodes in statvfs")
where statfs can report misleading / incorrect information where project quota is enabled, and the free space is less than the remaining quota.

This commit will resolve a test failure in generic/762 which tests for this bug.

generic/762 - output mismatch (see /share/git/fstests/results//generic/762.out.bad)
--- tests/generic/762.out 2025-04-15 10:21:53.371067071 +0800
+++ /share/git/fstests/results//generic/762.out.bad 2025-05-13 16:13:37.000000000 +0800
@@ -6,8 +6,10 @@
root blocks2 is in range
dir blocks2 is in range
root bavail2 is in range
-dir bavail2 is in range
+dir bavail2 has value of 1539066
+dir bavail2 is NOT in range 304734.87 .. 310891.13
root blocks3 is in range
...
(Run 'diff -u /share/git/fstests/tests/generic/762.out /share/git/fstests/results//generic/762.out.bad' to see the entire diff)

HINT: You _MAY_ be missing kernel fix:
XXXXXXXXXXXXXX xfs: don't over-report free space or inodes in statvfs

index b65d24a39d03..6744b8c65bc8 100644
@@ -1808,26 +1808,32 @@ static int f2fs_statfs_project(struct super_block *sb,
 
 	limit = min_not_zero(dquot->dq_dqb.dqb_bsoftlimit,
 					dquot->dq_dqb.dqb_bhardlimit);
-	if (limit)
-		limit >>= sb->s_blocksize_bits;
+	limit >>= sb->s_blocksize_bits;
+
+	if (limit) {
+		uint64_t remaining = 0;
 
-	if (limit && buf->f_blocks > limit) {
 		curblock = (dquot->dq_dqb.dqb_curspace +
 			    dquot->dq_dqb.dqb_rsvspace) >> sb->s_blocksize_bits;
-		buf->f_blocks = limit;
-		buf->f_bfree = buf->f_bavail =
-			(buf->f_blocks > curblock) ?
-			 (buf->f_blocks - curblock) : 0;
+		if (limit > curblock)
+			remaining = limit - curblock;
+
+		buf->f_blocks = min(buf->f_blocks, limit);
+		buf->f_bfree = min(buf->f_bfree, remaining);
+		buf->f_bavail = min(buf->f_bavail, remaining);
 	}
 
 	limit = min_not_zero(dquot->dq_dqb.dqb_isoftlimit,
 					dquot->dq_dqb.dqb_ihardlimit);
 
-	if (limit && buf->f_files > limit) {
-		buf->f_files = limit;
-		buf->f_ffree =
-			(buf->f_files > dquot->dq_dqb.dqb_curinodes) ?
-			 (buf->f_files - dquot->dq_dqb.dqb_curinodes) : 0;
+	if (limit) {
+		uint64_t remaining = 0;
+
+		if (limit > dquot->dq_dqb.dqb_curinodes)
+			remaining = limit - dquot->dq_dqb.dqb_curinodes;
+
+		buf->f_files = min(buf->f_files, limit);
+		buf->f_ffree = min(buf->f_ffree, remaining);
 	}
 
 	spin_unlock(&dquot->dq_dqb_lock);