On 2024/8/12 10:24, Gao Xiang wrote:
On 2024/8/11 16:09, Hongzhen Luo wrote:
When the `path` contains symbolic links, erofs_ilookup() does not
function properly. This adds support for symlink files.
Can you explain what's the use cases of this patch?
It seems both erofsfuse and fsck.erofs --extract don't need this.
Some third-party applications (such as Alibaba DADI) require obtaining
block mapping information of files based on their paths using liberofs.
When file paths include symbolic links, the current erofs_ilookup()
function fails to correctly locate the inode. This submission enhances
erofs_ilookup()'s support for symbolic link files.
Signed-off-by: Hongzhen Luo <[email protected]>
---
lib/namei.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/lib/namei.c b/lib/namei.c
index 6f35ee6..dce2991 100644
--- a/lib/namei.c
+++ b/lib/namei.c
@@ -195,6 +195,22 @@ struct nameidata {
unsigned int ftype;
};
+static int link_path_walk(const char *name, struct nameidata *nd);
+
+static int step_into_link(struct nameidata *nd, struct erofs_inode *vi)
+{
+ char buf[EROFS_MAX_BLOCK_SIZE];
+ int err;
+
+ if (vi->i_size > EROFS_MAX_BLOCK_SIZE)
+ return -EINVAL;
No, symlink size is independent to EROFS_MAX_BLOCK_SIZE, currently
it's hard-code as 4096.
Okay, I will make the corresponding modifications in the next version.
+ memset(buf, 0, sizeof(buf));
+ err = erofs_pread(vi, buf, vi->i_size, 0);
+ if (err)
+ return err;
+ return link_path_walk(buf, nd);
+}
+
int erofs_namei(struct nameidata *nd, const char *name, unsigned
int len)
{
erofs_nid_t nid = nd->nid;
@@ -233,6 +249,11 @@ int erofs_namei(struct nameidata *nd, const char
*name, unsigned int len)
return PTR_ERR(de);
if (de) {
+ vi.nid = de->nid;
+ ret = erofs_read_inode_from_disk(&vi);
+ if (S_ISLNK(vi.i_mode)) {
+ return step_into_link(nd, &vi);
+ }
Why need brace here?
Yes, the braces are not necessary, and I will clean them up later.
Thanks,
Gao Xiang
---
Thanks,
Hongzhen Luo
