Re: [PATCH v4 4/5] erofs: unify inline/share xattr iterators for listxattr/getxattr
From: Gao Xiang
Date: Wed May 31 2023 - 02:57:49 EST
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 <jefflexu@xxxxxxxxxxxxxxxxx>
---
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