Merge tag 'erofs-for-6.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs fixes from Gao Xiang:
 "Two patches fixes issues reported by syzbot, one fixes a missing
  `domain_id` mount option in documentation and a minor cleanup:

   - Fix wrong iomap->length calculation post EOF, which could cause a
     WARN_ON in iomap_iter_done() (Siddh)

   - Fix improper kvcalloc() use with __GFP_NOFAIL (me)

   - Add missing `domain_id` mount option in documentation (Jingbo)

   - Clean up fscache option parsing (Jingbo)"

* tag 'erofs-for-6.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: clean up parsing of fscache related options
  erofs: add documentation for 'domain_id' mount option
  erofs: fix kvcalloc() misuse with __GFP_NOFAIL
  erofs/zmap.c: Fix incorrect offset calculation

1 files changed, 7 insertions, 3 deletions

diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 0150570c33aa..98fb90b9af71 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -793,12 +793,16 @@ static int z_erofs_iomap_begin_report(struct inode *inode, loff_t offset,
 		iomap->type = IOMAP_HOLE;
 		iomap->addr = IOMAP_NULL_ADDR;
 		/*
-		 * No strict rule how to describe extents for post EOF, yet
-		 * we need do like below. Otherwise, iomap itself will get
+		 * No strict rule on how to describe extents for post EOF, yet
+		 * we need to do like below. Otherwise, iomap itself will get
 		 * into an endless loop on post EOF.
+		 *
+		 * Calculate the effective offset by subtracting extent start
+		 * (map.m_la) from the requested offset, and add it to length.
+		 * (NB: offset >= map.m_la always)
 		 */
 		if (iomap->offset >= inode->i_size)
-			iomap->length = length + map.m_la - offset;
+			iomap->length = length + offset - map.m_la;
 	}
 	iomap->flags = 0;
 	return 0;