Merge branch 'mm-hotfixes-stable' into mm-stable

1 files changed, 11 insertions, 0 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index f418d21205be..17adb7f6f6e4 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -950,6 +950,15 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
 		cond_resched();
 	}
 
+	/*
+	 * When undoing a failed fallocate, we want none of the partial folio
+	 * zeroing and splitting below, but shall want to truncate the whole
+	 * folio when !uptodate indicates that it was added by this fallocate,
+	 * even when [lstart, lend] covers only a part of the folio.
+	 */
+	if (unfalloc)
+		goto whole_folios;
+
 	same_folio = (lstart >> PAGE_SHIFT) == (lend >> PAGE_SHIFT);
 	folio = shmem_get_partial_folio(inode, lstart >> PAGE_SHIFT);
 	if (folio) {
@@ -975,6 +984,8 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
 		folio_put(folio);
 	}
 
+whole_folios:
+
 	index = start;
 	while (index < end) {
 		cond_resched();