Symlink lengths are now cached in in-memory inodes directly so that readlink can be sped up.
Signed-off-by: Gao Xiang <[email protected]> --- v2: - fix syzbot reports: https://syzkaller.appspot.com/bug?extid=c2dd47dc153320cc4692 fs/erofs/inode.c | 34 +++++++++++++++++++++------------- 1 file changed, 21 insertions(+), 13 deletions(-) diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c index 2ecc28abd6cd..294f66376825 100644 --- a/fs/erofs/inode.c +++ b/fs/erofs/inode.c @@ -8,21 +8,29 @@ #include <linux/compat.h> #include <trace/events/erofs.h> -static int erofs_fill_symlink(struct inode *inode, void *kaddr, - unsigned int m_pofs) +static int erofs_fill_symlink(struct inode *inode, void *bptr, unsigned int ofs) { struct erofs_inode *vi = EROFS_I(inode); - loff_t off; - - m_pofs += vi->xattr_isize; - /* check if it cannot be handled with fast symlink scheme */ - if (vi->datalayout != EROFS_INODE_FLAT_INLINE || - check_add_overflow(m_pofs, inode->i_size, &off) || - off > i_blocksize(inode)) - return 0; - - inode->i_link = kmemdup_nul(kaddr + m_pofs, inode->i_size, GFP_KERNEL); - return inode->i_link ? 0 : -ENOMEM; + char *link; + loff_t end; + + ofs += vi->xattr_isize; + /* check whether the symlink data is small enough to be inlined */ + if (vi->datalayout == EROFS_INODE_FLAT_INLINE && + !check_add_overflow(ofs, inode->i_size, &end) && + end <= i_blocksize(inode)) { + link = kmemdup_nul(bptr + ofs, inode->i_size, GFP_KERNEL); + if (!link) + return -ENOMEM; + if (unlikely(!inode->i_size || strlen(link) != inode->i_size)) { + erofs_err(inode->i_sb, "invalid fast symlink size %llu @ nid %llu", + inode->i_size | 0ULL, vi->nid); + kfree(link); + return -EFSCORRUPTED; + } + inode_set_cached_link(inode, link, inode->i_size); + } + return 0; } static int erofs_read_inode(struct inode *inode) -- 2.43.5
