When running ->fallocate(), blkdev_fallocate() should hold
mapping->invalidate_lock to prevent page cache from being
accessed, otherwise stale data may be read in page cache.
Without this patch, blktests block/009 fails sometimes. With
this patch, block/009 can pass always.
Cc: Jan Kara <jack@xxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
fs/block_dev.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 45df6cbccf12..f55e14ae89a0 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1516,7 +1516,8 @@ static const struct address_space_operations def_blk_aops = {
static long blkdev_fallocate(struct file *file, int mode, loff_t start,
loff_t len)
{
- struct block_device *bdev = I_BDEV(bdev_file_inode(file));
+ struct inode *inode = bdev_file_inode(file);
+ struct block_device *bdev = I_BDEV(inode);
loff_t end = start + len - 1;
loff_t isize;
int error;
@@ -1543,10 +1544,12 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start,
if ((start | len) & (bdev_logical_block_size(bdev) - 1))
return -EINVAL;
+ filemap_invalidate_lock(inode->i_mapping);
+
/* Invalidate the page cache, including dirty pages. */
error = truncate_bdev_range(bdev, file->f_mode, start, end);
if (error)
- return error;
+ goto fail;
switch (mode) {
case FALLOC_FL_ZERO_RANGE:
@@ -1563,17 +1566,18 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start,
GFP_KERNEL, 0);
break;
default:
- return -EOPNOTSUPP;
+ error = -EOPNOTSUPP;
}
- if (error)
- return error;
-
/*
* Invalidate the page cache again; if someone wandered in and dirtied
* a page, we just discard it - userspace has no way of knowing whether
* the write happened before or after discard completing...
*/
- return truncate_bdev_range(bdev, file->f_mode, start, end);
+ if (!error)
+ error = truncate_bdev_range(bdev, file->f_mode, start, end);
+ fail:
+ filemap_invalidate_unlock(inode->i_mapping);
+ return error;
}
const struct file_operations def_blk_fops = {
--
2.31.1
