On 2023/5/31 11:13, Jingbo Xu wrote:
Make inline_getxattr() and inline_listxattr() unified as
iter_inline_xattr(), shared_getxattr() and shared_listxattr() unified as
iter_shared_xattr().

After the unification, both iter_inline_xattr() and iter_shared_xattr()
return 0 on success, and negative error on failure.

One thing worth noting is that, the logic of returning it->buffer_ofs
when there's no shared xattrs in shared_listxattr() is moved to
erofs_listxattr() to make the unification possible.  The only difference
is that, semantically the old behavior will return ENOATTR rather than
it->buffer_ofs if ENOATTR encountered when listxattr is parsing upon a
specific shared xattr, while now the new behavior will return
it->buffer_ofs in this case.  This is not an issue, as listxattr upon a
specific xattr won't return ENOATTR.

Signed-off-by: Jingbo Xu <[email protected]>
---
  fs/erofs/xattr.c | 210 ++++++++++++++++++-----------------------------
  1 file changed, 78 insertions(+), 132 deletions(-)

diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index 7c76b4d31920..074743e2b271 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -7,19 +7,6 @@
  #include <linux/security.h>
  #include "xattr.h"
-static inline erofs_blk_t erofs_xattr_blkaddr(struct super_block *sb,
-                                             unsigned int xattr_id)
-{
-       return EROFS_SB(sb)->xattr_blkaddr +
-              erofs_blknr(sb, xattr_id * sizeof(__u32));
-}
-
-static inline unsigned int erofs_xattr_blkoff(struct super_block *sb,
-                                             unsigned int xattr_id)
-{
-       return erofs_blkoff(sb, xattr_id * sizeof(__u32));
-}
-
  struct erofs_xattr_iter {
        struct super_block *sb;
        struct erofs_buf buf;
@@ -170,30 +157,6 @@ struct xattr_iter_handlers {
                      unsigned int len);
  };
-static int inline_xattr_iter_begin(struct erofs_xattr_iter *it,
-                                  struct inode *inode)
-{
-       struct erofs_inode *const vi = EROFS_I(inode);
-       unsigned int xattr_header_sz, inline_xattr_ofs;
-
-       xattr_header_sz = sizeof(struct erofs_xattr_ibody_header) +
-                         sizeof(u32) * vi->xattr_shared_count;
-       if (xattr_header_sz >= vi->xattr_isize) {
-               DBG_BUGON(xattr_header_sz > vi->xattr_isize);
-               return -ENOATTR;
-       }
-
-       inline_xattr_ofs = vi->inode_isize + xattr_header_sz;
-
-       it->blkaddr = erofs_blknr(it->sb, erofs_iloc(inode) + inline_xattr_ofs);
-       it->ofs = erofs_blkoff(it->sb, erofs_iloc(inode) + inline_xattr_ofs);
-       it->kaddr = erofs_read_metabuf(&it->buf, inode->i_sb, it->blkaddr,
-                                      EROFS_KMAP);
-       if (IS_ERR(it->kaddr))
-               return PTR_ERR(it->kaddr);
-       return vi->xattr_isize - xattr_header_sz;
-}
-
  /*
   * Regardless of success or failure, `xattr_foreach' will end up with
   * `ofs' pointing to the next xattr item rather than an arbitrary position.
@@ -355,46 +318,6 @@ static const struct xattr_iter_handlers 
find_xattr_handlers = {
        .value = xattr_copyvalue
  };
-static int inline_getxattr(struct inode *inode, struct erofs_xattr_iter *it)
-{
-       int ret;
-       unsigned int remaining;
-
-       ret = inline_xattr_iter_begin(it, inode);
-       if (ret < 0)
-               return ret;
-
-       remaining = ret;
-       while (remaining) {
-               ret = xattr_foreach(it, &find_xattr_handlers, &remaining);
-               if (ret != -ENOATTR)
-                       break;
-       }
-       return ret ? ret : it->buffer_ofs;
-}
-
-static int shared_getxattr(struct inode *inode, struct erofs_xattr_iter *it)
-{
-       struct erofs_inode *const vi = EROFS_I(inode);
-       struct super_block *const sb = it->sb;
-       unsigned int i, xsid;
-       int ret = -ENOATTR;
-
-       for (i = 0; i < vi->xattr_shared_count; ++i) {
-               xsid = vi->xattr_shared_xattrs[i];
-               it->blkaddr = erofs_xattr_blkaddr(sb, xsid);
-               it->ofs = erofs_xattr_blkoff(sb, xsid);
-               it->kaddr = erofs_read_metabuf(&it->buf, sb, it->blkaddr, 
EROFS_KMAP);
-               if (IS_ERR(it->kaddr))
-                       return PTR_ERR(it->kaddr);
-
-               ret = xattr_foreach(it, &find_xattr_handlers, NULL);
-               if (ret != -ENOATTR)
-                       break;
-       }
-       return ret ? ret : it->buffer_ofs;
-}
-
  static bool erofs_xattr_user_list(struct dentry *dentry)
  {
        return test_opt(&EROFS_SB(dentry->d_sb)->opt, XATTR_USER);
@@ -405,39 +328,6 @@ static bool erofs_xattr_trusted_list(struct dentry *dentry)
        return capable(CAP_SYS_ADMIN);
  }
-int erofs_getxattr(struct inode *inode, int index,
-                  const char *name,
-                  void *buffer, size_t buffer_size)
-{
-       int ret;
-       struct erofs_xattr_iter it;
-
-       if (!name)
-               return -EINVAL;
-
-       ret = erofs_init_inode_xattrs(inode);
-       if (ret)
-               return ret;
-
-       it.index = index;
-       it.name = (struct qstr)QSTR_INIT(name, strlen(name));
-       if (it.name.len > EROFS_NAME_LEN)
-               return -ERANGE;
-
-       it.sb = inode->i_sb;
-       it.buf = __EROFS_BUF_INITIALIZER;
-       erofs_init_metabuf(&it.buf, it.sb);
-       it.buffer = buffer;
-       it.buffer_size = buffer_size;
-       it.buffer_ofs = 0;
-
-       ret = inline_getxattr(inode, &it);
-       if (ret == -ENOATTR)
-               ret = shared_getxattr(inode, &it);
-       erofs_put_metabuf(&it.buf);
-       return ret;
-}
-
  static int erofs_xattr_generic_get(const struct xattr_handler *handler,
                                   struct dentry *unused, struct inode *inode,
                                   const char *name, void *buffer, size_t size)
@@ -542,45 +432,98 @@ static const struct xattr_iter_handlers 
list_xattr_handlers = {
        .value = NULL
  };
-static int inline_listxattr(struct erofs_xattr_iter *it)
+static int erofs_iter_inline_xattr(struct erofs_xattr_iter *it,
+                                  struct inode *inode, bool getxattr)
  {
+       struct erofs_inode *const vi = EROFS_I(inode);
+       const struct xattr_iter_handlers *op;
+       unsigned int xattr_header_sz, remaining;
+       erofs_off_t pos;
        int ret;
-       unsigned int remaining;
- ret = inline_xattr_iter_begin(it, d_inode(it->dentry));

In the past, "ret" here is "an int", and
        vi->xattr_isize - xattr_header_sz < 0 will return
negative value (although I think that value is problematic).

see below.


-       if (ret < 0)
-               return ret;
+       xattr_header_sz = sizeof(struct erofs_xattr_ibody_header) +
+                         sizeof(u32) * vi->xattr_shared_count;
+       if (xattr_header_sz >= vi->xattr_isize) {
+               DBG_BUGON(xattr_header_sz > vi->xattr_isize);
+               return -ENOATTR;
+       }
+
+       pos = erofs_iloc(inode) + vi->inode_isize + xattr_header_sz;
+       it->blkaddr = erofs_blknr(it->sb, pos);
+       it->ofs = erofs_blkoff(it->sb, pos);
+       it->kaddr = erofs_read_metabuf(&it->buf, it->sb, it->blkaddr, 
EROFS_KMAP);
+       if (IS_ERR(it->kaddr))
+               return PTR_ERR(it->kaddr);
+
+       remaining = vi->xattr_isize - xattr_header_sz;

so in this patch, `vi->xattr_isize - xattr_header_sz` here could be
negative that should be avoided as well.

Thanks,
Gao Xiang

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