Re: [PATCH bpf-next v2 1/3] libfs: support RENAME_EXCHANGE in simple_rename()
From: Daniel Borkmann <daniel@iogearbox.net>
Date: 2021-10-27 23:21:22
Also in:
bpf, linux-fsdevel, lkml
[ Adding Miklos & Greg to Cc for review given e0e0be8a8355 ("libfs: support RENAME_NOREPLACE in
simple_rename()"). If you have a chance, would be great if you could take a look, thanks! ]
On 10/21/21 5:15 PM, Lorenz Bauer wrote:quoted hunk ↗ jump to hunk
Allow atomic exchange via RENAME_EXCHANGE when using simple_rename. This affects binderfs, ramfs, hubetlbfs and bpffs. There isn't much to do except update the various *time fields. Signed-off-by: Lorenz Bauer <redacted> --- fs/libfs.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)diff --git a/fs/libfs.c b/fs/libfs.c index 51b4de3b3447..93c03d593749 100644 --- a/fs/libfs.c +++ b/fs/libfs.c@@ -455,9 +455,12 @@ int simple_rename(struct user_namespace *mnt_userns, struct inode *old_dir, struct inode *inode = d_inode(old_dentry); int they_are_dirs = d_is_dir(old_dentry); - if (flags & ~RENAME_NOREPLACE) + if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) return -EINVAL; + if (flags & RENAME_EXCHANGE) + goto done; + if (!simple_empty(new_dentry)) return -ENOTEMPTY;@@ -472,6 +475,7 @@ int simple_rename(struct user_namespace *mnt_userns, struct inode *old_dir, inc_nlink(new_dir); } +done: old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = new_dir->i_mtime = inode->i_ctime = current_time(old_dir);