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-rw-r--r--fs/btrfs/file.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 04faa04fccd1..6d5d905281c6 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1904,18 +1904,29 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
pos = iocb->ki_pos;
count = iov_iter_count(from);
if (iocb->ki_flags & IOCB_NOWAIT) {
+ size_t nocow_bytes = count;
+
/*
* We will allocate space in case nodatacow is not set,
* so bail
*/
if (!(BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
BTRFS_INODE_PREALLOC)) ||
- check_can_nocow(BTRFS_I(inode), pos, &count) <= 0) {
+ check_can_nocow(BTRFS_I(inode), pos, &nocow_bytes) <= 0) {
inode_unlock(inode);
return -EAGAIN;
}
/* check_can_nocow() locks the snapshot lock on success */
btrfs_drew_write_unlock(&root->snapshot_lock);
+ /*
+ * There are holes in the range or parts of the range that must
+ * be COWed (shared extents, RO block groups, etc), so just bail
+ * out.
+ */
+ if (nocow_bytes < count) {
+ inode_unlock(inode);
+ return -EAGAIN;
+ }
}
current->backing_dev_info = inode_to_bdi(inode);