f2fs: Create COW inode from parent dentry for atomic write

The i_pino in f2fs_inode_info has the previous parent's i_ino when inode
was renamed, which may cause f2fs_ioc_start_atomic_write to fail.
If file_wrong_pino is true and i_nlink is 1, then to find a valid pino,
we should refer to the dentry from inode.

To resolve this issue, let's get parent inode using parent dentry
directly.

Fixes: 3db1de0e582c ("f2fs: change the current atomic write way")
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Reviewed-by: Sunmin Jeong <s_min.jeong@samsung.com>
Signed-off-by: Yeongjin Gil <youngjin.gil@samsung.com>
Reviewed-by: Daeho Jeong <daehojeong@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 2c591fbc75a9e5d0a4ca8a19a736a82b43edbdc5..082e81ba09b9eda1976882d3474b580528e3d713 100644 (file)
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2127,7 +2127,6 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate)
        struct mnt_idmap *idmap = file_mnt_idmap(filp);
        struct f2fs_inode_info *fi = F2FS_I(inode);
        struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
-       struct inode *pinode;
        loff_t isize;
        int ret;
 
@@ -2180,15 +2179,10 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate)
        /* Check if the inode already has a COW inode */
        if (fi->cow_inode == NULL) {
                /* Create a COW inode for atomic write */
-               pinode = f2fs_iget(inode->i_sb, fi->i_pino);
-               if (IS_ERR(pinode)) {
-                       f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
-                       ret = PTR_ERR(pinode);
-                       goto out;
-               }
+               struct dentry *dentry = file_dentry(filp);
+               struct inode *dir = d_inode(dentry->d_parent);
 
-               ret = f2fs_get_tmpfile(idmap, pinode, &fi->cow_inode);
-               iput(pinode);
+               ret = f2fs_get_tmpfile(idmap, dir, &fi->cow_inode);
                if (ret) {
                        f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
                        goto out;