FAILED: patch "[PATCH] f2fs: fix to requery extent which cross boundary of inquiry" failed to apply to 6.12-stable tree

The patch below does not apply to the 6.12-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-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 6787a82245857271133b63ae7f72f1dc9f29e985
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2024120628-crazy-studio-e1dc@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 6787a82245857271133b63ae7f72f1dc9f29e985 Mon Sep 17 00:00:00 2001
From: Chao Yu <[email protected]>
Date: Fri, 8 Nov 2024 09:25:57 +0800
Subject: [PATCH] f2fs: fix to requery extent which cross boundary of inquiry

dd if=/dev/zero of=file bs=4k count=5
xfs_io file -c "fiemap -v 2 16384"
file:

   EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
     0: [0..31]:         139272..139303      32 0x1000
     1: [32..39]:        139304..139311       8 0x1001
xfs_io file -c "fiemap -v 0 16384"
file:
   EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
     0: [0..31]:         139272..139303      32 0x1000
xfs_io file -c "fiemap -v 0 16385"
file:
   EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
     0: [0..39]:         139272..139311      40 0x1001

There are two problems:
- continuous extent is split to two
- FIEMAP_EXTENT_LAST is missing in last extent

The root cause is: if upper boundary of inquiry crosses extent, f2fs_map_blocks() will truncate length of returned extent to F2FS_BYTES_TO_BLK(len), and also, it will stop to query latter extent or hole to make sure current extent is last or not.

In order to fix this issue, once we found an extent locates in the end of inquiry range by f2fs_map_blocks(), we need to expand inquiry range to requiry.

index 69f1cb0490ee..ee5614324df0 100644
@@ -1896,7 +1896,7 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 		u64 start, u64 len)
 {
 	struct f2fs_map_blocks map;
-	sector_t start_blk, last_blk;
+	sector_t start_blk, last_blk, blk_len, max_len;
 	pgoff_t next_pgofs;
 	u64 logical = 0, phys = 0, size = 0;
 	u32 flags = 0;

@@ -1940,14 +1940,13 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 
 	start_blk = F2FS_BYTES_TO_BLK(start);
 	last_blk = F2FS_BYTES_TO_BLK(start + len - 1);
-
-	if (len & F2FS_BLKSIZE_MASK)
-		len = round_up(len, F2FS_BLKSIZE);
+	blk_len = last_blk - start_blk + 1;
+	max_len = F2FS_BYTES_TO_BLK(maxbytes) - start_blk;
 
 next:
 	memset(&map, 0, sizeof(map));
 	map.m_lblk = start_blk;
-	map.m_len = F2FS_BYTES_TO_BLK(len);
+	map.m_len = blk_len;
 	map.m_next_pgofs = &next_pgofs;
 	map.m_seg_type = NO_CHECK_TYPE;
 

@@ -1970,6 +1969,17 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 		flags |= FIEMAP_EXTENT_LAST;
 	}
 
+	/*
+	 * current extent may cross boundary of inquiry, increase len to
+	 * requery.
+	 */
+	if (!compr_cluster && (map.m_flags & F2FS_MAP_MAPPED) &&
+				map.m_lblk + map.m_len - 1 == last_blk &&
+				blk_len != max_len) {
+		blk_len = max_len;
+		goto next;
+	}
+
 	compr_appended = false;
 	/* In a case of compressed cluster, append this to the last extent */
 	if (compr_cluster && ((map.m_flags & F2FS_MAP_DELALLOC) ||