After cloning the required extents, we truncate all the pages that map
the file range being cloned. In subpage-blocksize scenario, we could
have dirty blocks before and/or after the clone range in the
leading/trailing pages. Truncating these pages would lead to data
loss. Hence this commit forces such dirty blocks to be flushed to disk
before performing the clone operation.
Signed-off-by: Chandan Rajendra <chan...@linux.vnet.ibm.com>
---
fs/btrfs/ioctl.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 4ff7cf8..7d39cba 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3849,6 +3849,7 @@ static noinline int btrfs_clone_files(struct file *file,
struct file *file_src,
int ret;
u64 len = olen;
u64 bs = root->fs_info->sb->s_blocksize;
+ u64 dest_end;
int same_inode = src == inode;
/*
@@ -3909,6 +3910,21 @@ static noinline int btrfs_clone_files(struct file *file,
struct file *file_src,
goto out_unlock;
}
+ if ((round_down(destoff, PAGE_SIZE) < inode->i_size) &&
+ !IS_ALIGNED(destoff, PAGE_SIZE)) {
+ ret = filemap_write_and_wait_range(inode->i_mapping,
+ round_down(destoff, PAGE_SIZE),
+ destoff - 1);
+ }
+
+ dest_end = destoff + len - 1;
+ if ((dest_end < inode->i_size) &&
+ !IS_ALIGNED(dest_end + 1, PAGE_SIZE)) {
+ ret = filemap_write_and_wait_range(inode->i_mapping,
+ dest_end + 1,
+ round_up(dest_end, PAGE_SIZE));
+ }
+
if (destoff > inode->i_size) {
ret = btrfs_cont_expand(inode, inode->i_size, destoff);
if (ret)
--
2.1.0
--
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