On 2023/5/31 11:13, Jingbo Xu wrote:
Enhance erofs_xattr_iter_fixup() helper so that it could be reused in
the situation where it.ofs could not span the block boundary.

Besides call erofs_init_metabuf() and erofs_bread() separately to avoid
the repetition of assigning buf->inode when iterating xattrs.

Signed-off-by: Jingbo Xu <[email protected]>

Reviewed-by: Gao Xiang <[email protected]>

Thanks,
Gao Xiang

---
  fs/erofs/xattr.c | 82 +++++++++++++++++++++---------------------------
  1 file changed, 35 insertions(+), 47 deletions(-)

diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index bbfe7ce170d2..df6c4e6f1f4e 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -29,6 +29,24 @@ struct xattr_iter {
        unsigned int ofs;
  };
+static inline int erofs_xattr_iter_fixup(struct xattr_iter *it, bool nospan)
+{
+       if (it->ofs < it->sb->s_blocksize)
+               return 0;
+
+       if (nospan && it->ofs != it->sb->s_blocksize) {
+               DBG_BUGON(1);
+               return -EFSCORRUPTED;
+       }
+
+       it->blkaddr += erofs_blknr(it->sb, it->ofs);
+       it->kaddr = erofs_bread(&it->buf, it->blkaddr, EROFS_KMAP);
+       if (IS_ERR(it->kaddr))
+               return PTR_ERR(it->kaddr);
+       it->ofs = erofs_blkoff(it->sb, it->ofs);
+       return 0;
+}
+
  static int erofs_init_inode_xattrs(struct inode *inode)
  {
        struct erofs_inode *const vi = EROFS_I(inode);
@@ -80,6 +98,7 @@ static int erofs_init_inode_xattrs(struct inode *inode)
                goto out_unlock;
        }
+ it.sb = sb;
        it.buf = __EROFS_BUF_INITIALIZER;
        it.blkaddr = erofs_blknr(sb, erofs_iloc(inode) + vi->inode_isize);
        it.ofs = erofs_blkoff(sb, erofs_iloc(inode) + vi->inode_isize);
@@ -105,19 +124,11 @@ static int erofs_init_inode_xattrs(struct inode *inode)
        it.ofs += sizeof(struct erofs_xattr_ibody_header);
for (i = 0; i < vi->xattr_shared_count; ++i) {
-               if (it.ofs >= sb->s_blocksize) {
-                       /* cannot be unaligned */
-                       DBG_BUGON(it.ofs != sb->s_blocksize);
-
-                       it.kaddr = erofs_read_metabuf(&it.buf, sb, ++it.blkaddr,
-                                                     EROFS_KMAP);
-                       if (IS_ERR(it.kaddr)) {
-                               kfree(vi->xattr_shared_xattrs);
-                               vi->xattr_shared_xattrs = NULL;
-                               ret = PTR_ERR(it.kaddr);
-                               goto out_unlock;
-                       }
-                       it.ofs = 0;
+               ret = erofs_xattr_iter_fixup(&it, true);
+               if (ret) {
+                       kfree(vi->xattr_shared_xattrs);
+                       vi->xattr_shared_xattrs = NULL;
+                       goto out_unlock;
                }
                vi->xattr_shared_xattrs[i] =
                        le32_to_cpu(*(__le32 *)(it.kaddr + it.ofs));
@@ -150,20 +161,6 @@ struct xattr_iter_handlers {
                      unsigned int len);
  };
-static inline int xattr_iter_fixup(struct xattr_iter *it)
-{
-       if (it->ofs < it->sb->s_blocksize)
-               return 0;
-
-       it->blkaddr += erofs_blknr(it->sb, it->ofs);
-       it->kaddr = erofs_read_metabuf(&it->buf, it->sb, it->blkaddr,
-                                      EROFS_KMAP);
-       if (IS_ERR(it->kaddr))
-               return PTR_ERR(it->kaddr);
-       it->ofs = erofs_blkoff(it->sb, it->ofs);
-       return 0;
-}
-
  static int inline_xattr_iter_begin(struct xattr_iter *it,
                                   struct inode *inode)
  {
@@ -201,7 +198,7 @@ static int xattr_foreach(struct xattr_iter *it,
        int err;
/* 0. fixup blkaddr, ofs, ipage */
-       err = xattr_iter_fixup(it);
+       err = erofs_xattr_iter_fixup(it, false);
        if (err)
                return err;
@@ -236,14 +233,9 @@ static int xattr_foreach(struct xattr_iter *it,
        processed = 0;
while (processed < entry.e_name_len) {
-               if (it->ofs >= it->sb->s_blocksize) {
-                       DBG_BUGON(it->ofs > it->sb->s_blocksize);
-
-                       err = xattr_iter_fixup(it);
-                       if (err)
-                               goto out;
-                       it->ofs = 0;
-               }
+               err = erofs_xattr_iter_fixup(it, true);
+               if (err)
+                       goto out;
slice = min_t(unsigned int, it->sb->s_blocksize - it->ofs,
                              entry.e_name_len - processed);
@@ -271,14 +263,9 @@ static int xattr_foreach(struct xattr_iter *it,
        }
while (processed < value_sz) {
-               if (it->ofs >= it->sb->s_blocksize) {
-                       DBG_BUGON(it->ofs > it->sb->s_blocksize);
-
-                       err = xattr_iter_fixup(it);
-                       if (err)
-                               goto out;
-                       it->ofs = 0;
-               }
+               err = erofs_xattr_iter_fixup(it, true);
+               if (err)
+                       goto out;
slice = min_t(unsigned int, it->sb->s_blocksize - it->ofs,
                              value_sz - processed);
@@ -444,13 +431,14 @@ int erofs_getxattr(struct inode *inode, int index,
        if (it.name.len > EROFS_NAME_LEN)
                return -ERANGE;
+ it.it.sb = inode->i_sb;
        it.it.buf = __EROFS_BUF_INITIALIZER;
+       erofs_init_metabuf(&it.it.buf, it.it.sb);
        it.name.name = name;
it.buffer = buffer;
        it.buffer_size = buffer_size;
- it.it.sb = inode->i_sb;
        ret = inline_getxattr(inode, &it);
        if (ret == -ENOATTR)
                ret = shared_getxattr(inode, &it);
@@ -632,14 +620,14 @@ ssize_t erofs_listxattr(struct dentry *dentry,
        if (ret)
                return ret;
+ it.it.sb = dentry->d_sb;
        it.it.buf = __EROFS_BUF_INITIALIZER;
+       erofs_init_metabuf(&it.it.buf, it.it.sb);
        it.dentry = dentry;
        it.buffer = buffer;
        it.buffer_size = buffer_size;
        it.buffer_ofs = 0;
- it.it.sb = dentry->d_sb;
-
        ret = inline_listxattr(&it);
        if (ret >= 0 || ret == -ENOATTR)
                ret = shared_listxattr(&it);

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