Per-inode xattr handlers allow to mark inodes as bad and dirs as "empty"
in the usual way even when using generic_getxattr, generic_setxattr, and
generic_removexattr. This brings us one step closer to getting rid of
the getxattr, setxattr, and removexattr inode operations.
Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
---
fs/bad_inode.c | 36 +++++++++++++++++++++++-------------
fs/libfs.c | 29 +++++++++--------------------
fs/xattr.c | 17 ++++++++++-------
include/linux/fs.h | 1 +
include/linux/xattr.h | 6 ++++++
5 files changed, 49 insertions(+), 40 deletions(-)
diff --git a/fs/bad_inode.c b/fs/bad_inode.c
index 72e35b7..e9227ea2d 100644
--- a/fs/bad_inode.c
+++ b/fs/bad_inode.c
@@ -14,6 +14,7 @@
#include <linux/time.h>
#include <linux/namei.h>
#include <linux/poll.h>
+#include <linux/xattr.h>
static int bad_file_open(struct inode *inode, struct file *filp)
{
@@ -100,28 +101,36 @@ static int bad_inode_setattr(struct dentry *direntry, struct iattr *attrs)
return -EIO;
}
-static int bad_inode_setxattr(struct dentry *dentry, const char *name,
- const void *value, size_t size, int flags)
+static ssize_t bad_inode_listxattr(struct dentry *dentry, char *buffer,
+ size_t buffer_size)
{
return -EIO;
}
-static ssize_t bad_inode_getxattr(struct dentry *dentry, struct inode *inode,
- const char *name, void *buffer, size_t size)
+static int bad_inode_xattr_get(const struct xattr_handler *handler,
+ struct dentry *dentry, struct inode *inode,
+ const char *name, void *buffer, size_t size)
{
return -EIO;
}
-static ssize_t bad_inode_listxattr(struct dentry *dentry, char *buffer,
- size_t buffer_size)
+static int bad_inode_xattr_set(const struct xattr_handler *handler,
+ struct dentry *dentry, const char *name,
+ const void *buffer, size_t size, int flags)
{
return -EIO;
}
-static int bad_inode_removexattr(struct dentry *dentry, const char *name)
-{
- return -EIO;
-}
+static const struct xattr_handler bad_inode_xattr_handler = {
+ .prefix = "", /* match anything */
+ .get = bad_inode_xattr_get,
+ .set = bad_inode_xattr_set,
+};
+
+static const struct xattr_handler *bad_inode_xattr_handlers[] = {
+ &bad_inode_xattr_handler,
+ NULL
+};
static const struct inode_operations bad_inode_ops =
{
@@ -142,10 +151,11 @@ static const struct inode_operations bad_inode_ops =
.permission = bad_inode_permission,
.getattr = bad_inode_getattr,
.setattr = bad_inode_setattr,
- .setxattr = bad_inode_setxattr,
- .getxattr = bad_inode_getxattr,
+ .setxattr = generic_setxattr,
+ .getxattr = generic_getxattr,
.listxattr = bad_inode_listxattr,
- .removexattr = bad_inode_removexattr,
+ .removexattr = generic_removexattr,
+ .xattr = bad_inode_xattr_handlers,
};
diff --git a/fs/libfs.c b/fs/libfs.c
index 2a820bb..a7cea0a 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -15,6 +15,7 @@
#include <linux/exportfs.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h> /* sync_mapping_buffers */
+#include <linux/xattr.h>
#include <asm/uaccess.h>
@@ -1122,37 +1123,25 @@ static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr)
return -EPERM;
}
-static int empty_dir_setxattr(struct dentry *dentry, const char *name,
- const void *value, size_t size, int flags)
-{
- return -EOPNOTSUPP;
-}
-
-static ssize_t empty_dir_getxattr(struct dentry *dentry, struct inode *inode,
- const char *name, void *value, size_t size)
-{
- return -EOPNOTSUPP;
-}
-
-static int empty_dir_removexattr(struct dentry *dentry, const char *name)
-{
- return -EOPNOTSUPP;
-}
-
static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size)
{
return -EOPNOTSUPP;
}
+static const struct xattr_handler *empty_dir_xattr_handlers[] = {
+ NULL
+};
+
static const struct inode_operations empty_dir_inode_operations = {
.lookup = empty_dir_lookup,
.permission = generic_permission,
.setattr = empty_dir_setattr,
.getattr = empty_dir_getattr,
- .setxattr = empty_dir_setxattr,
- .getxattr = empty_dir_getxattr,
- .removexattr = empty_dir_removexattr,
+ .setxattr = generic_setxattr,
+ .getxattr = generic_getxattr,
+ .removexattr = generic_removexattr,
.listxattr = empty_dir_listxattr,
+ .xattr = empty_dir_xattr_handlers,
};
static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence)
diff --git a/fs/xattr.c b/fs/xattr.c
index b11945e..68e093e 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -649,7 +649,8 @@ strcmp_prefix(const char *a, const char *a_prefix)
* In order to implement different sets of xattr operations for each xattr
* prefix with the generic xattr API, a filesystem should create a
* null-terminated array of struct xattr_handler (one for each prefix) and
- * hang a pointer to it off of the s_xattr field of the superblock.
+ * hang a pointer to it off of the xattr field of the inode operations or
+ * the s_xattr field of the superblock.
*
* The generic_fooxattr() functions will use this list to dispatch xattr
* operations to the correct xattr_handler.
@@ -663,13 +664,14 @@ strcmp_prefix(const char *a, const char *a_prefix)
* Find the xattr_handler with the matching prefix.
*/
static const struct xattr_handler *
-xattr_resolve_name(const struct xattr_handler **handlers, const char **name)
+xattr_resolve_name(const struct dentry *dentry, const char **name)
{
- const struct xattr_handler *handler;
+ const struct xattr_handler *handler, **handlers;
if (!*name)
return NULL;
+ handlers = xattr_handlers(dentry->d_inode);
for_each_xattr_handler(handlers, handler) {
const char *n;
@@ -696,7 +698,7 @@ generic_getxattr(struct dentry *dentry, struct inode *inode,
{
const struct xattr_handler *handler;
- handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
+ handler = xattr_resolve_name(dentry, &name);
if (IS_ERR(handler))
return PTR_ERR(handler);
return handler->get(handler, dentry, inode,
@@ -710,9 +712,10 @@ generic_getxattr(struct dentry *dentry, struct inode *inode,
ssize_t
generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
{
- const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr;
+ const struct xattr_handler *handler, **handlers;
unsigned int size = 0;
+ handlers = xattr_handlers(dentry->d_inode);
if (!buffer) {
for_each_xattr_handler(handlers, handler) {
if (!handler->name ||
@@ -750,7 +753,7 @@ generic_setxattr(struct dentry *dentry, const char *name, const void *value, siz
if (size == 0)
value = ""; /* empty EA, do not remove */
- handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
+ handler = xattr_resolve_name(dentry, &name);
if (IS_ERR(handler))
return PTR_ERR(handler);
return handler->set(handler, dentry, name, value, size, flags);
@@ -765,7 +768,7 @@ generic_removexattr(struct dentry *dentry, const char *name)
{
const struct xattr_handler *handler;
- handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
+ handler = xattr_resolve_name(dentry, &name);
if (IS_ERR(handler))
return PTR_ERR(handler);
return handler->set(handler, dentry, name, NULL, 0, XATTR_REPLACE);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3489609..4f25cd3 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1714,6 +1714,7 @@ struct inode_operations {
umode_t create_mode, int *opened);
int (*tmpfile) (struct inode *, struct dentry *, umode_t);
int (*set_acl)(struct inode *, struct posix_acl *, int);
+ const struct xattr_handler **xattr;
} ____cacheline_aligned;
ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
diff --git a/include/linux/xattr.h b/include/linux/xattr.h
index 1cc4c57..2d30a3b 100644
--- a/include/linux/xattr.h
+++ b/include/linux/xattr.h
@@ -14,6 +14,7 @@
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/spinlock.h>
+#include <linux/fs.h>
#include <uapi/linux/xattr.h>
struct inode;
@@ -64,6 +65,11 @@ static inline const char *xattr_prefix(const struct xattr_handler *handler)
return handler->prefix ?: handler->name;
}
+static inline const struct xattr_handler **xattr_handlers(struct inode *inode)
+{
+ return inode->i_op->xattr ?: inode->i_sb->s_xattr;
+}
+
struct simple_xattrs {
struct list_head head;
spinlock_t lock;
--
2.5.5
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