Align start and end on page boundaries before calling
invalidate_inode_pages2_range.
This might allow us to miss a collision if the write and the discard were done
to the same page and do overlap but it is still better than returning -EBUSY
if those writes didn't overlap.
Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
---
fs/block_dev.c | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 9e84b1928b94..97f0d16661b5 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1970,6 +1970,7 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start,
loff_t end = start + len - 1;
loff_t isize;
int error;
+ pgoff_t invalidate_first_page, invalidate_last_page;
/* Fail if we don't recognize the flags. */
if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED)
@@ -2020,12 +2021,23 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start,
/*
* Invalidate again; if someone wandered in and dirtied a page,
- * the caller will be given -EBUSY. The third argument is
- * inclusive, so the rounding here is safe.
+ * the caller will be given -EBUSY.
+ *
+ * If the start/end of the range is not page aligned, exclude the
+ * non aligned regions to avoid false positives.
*/
+ invalidate_first_page = DIV_ROUND_UP(start, PAGE_SIZE);
+ invalidate_last_page = end >> PAGE_SHIFT;
+
+ if ((end + 1) & PAGE_MASK)
+ invalidate_last_page--;
+
+ if (invalidate_last_page < invalidate_first_page)
+ return 0;
+
return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping,
- start >> PAGE_SHIFT,
- end >> PAGE_SHIFT);
+ invalidate_first_page,
+ invalidate_last_page);
}
const struct file_operations def_blk_fops = {
--
2.26.2
