On 2017/2/15 2:03, Jaegeuk Kim wrote: > VFS uses f2fs_lookup() to decide f2fs_add_link() call during file creation. > But, if there is a race condition, f2fs_add_link() can be called multiple > times, resulting in multiple dentries with a same name. This patches fixes > it by adding __f2fs_find_entry() in f2fs_add_link() path.
As during ->lookup, i_mutex will be held all the time, so there is no race condition in between different file creators? Thanks, > > Cc: <[email protected]> > Signed-off-by: Jaegeuk Kim <[email protected]> > --- > fs/f2fs/dir.c | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c > index 827c5daef4fc..bc7c48839bec 100644 > --- a/fs/f2fs/dir.c > +++ b/fs/f2fs/dir.c > @@ -643,14 +643,24 @@ int __f2fs_add_link(struct inode *dir, const struct > qstr *name, > struct inode *inode, nid_t ino, umode_t mode) > { > struct fscrypt_name fname; > + struct page *page; > + struct f2fs_dir_entry *de; > int err; > > err = fscrypt_setup_filename(dir, name, 0, &fname); > if (err) > return err; > > - err = __f2fs_do_add_link(dir, &fname, inode, ino, mode); > - > + de = __f2fs_find_entry(dir, &fname, &page); > + if (de) { > + f2fs_dentry_kunmap(dir, page); > + f2fs_put_page(page, 0); > + err = -EEXIST; > + } else if (!IS_ERR(page)) { > + err = __f2fs_do_add_link(dir, &fname, inode, ino, mode); > + } else { > + err = PTR_ERR(page); > + } > fscrypt_free_filename(&fname); > return err; > } > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
