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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] xen/hypfs: add getsize() and findentry() callbacks to hypfs_funcs
commit be3755af37263833cb3b1c6b1f2ba219bdf97ec3
Author: Juergen Gross <jgross@xxxxxxxx>
AuthorDate: Fri Dec 4 08:31:25 2020 +0100
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Dec 4 08:31:25 2020 +0100
xen/hypfs: add getsize() and findentry() callbacks to hypfs_funcs
Add a getsize() function pointer to struct hypfs_funcs for being able
to have dynamically filled entries without the need to take the hypfs
lock each time the contents are being generated.
For directories add a findentry callback to the vector and modify
hypfs_get_entry_rel() to use it. For its non-directory node counterpart
introduce the so far unused and hence missing ENOTDIR error code.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
xen/common/hypfs.c | 100 +++++++++++++++++++++++++++++----------------
xen/include/public/errno.h | 1 +
xen/include/xen/hypfs.h | 25 +++++++++++-
3 files changed, 90 insertions(+), 36 deletions(-)
diff --git a/xen/common/hypfs.c b/xen/common/hypfs.c
index fdfd0f764a..2e8e90591e 100644
--- a/xen/common/hypfs.c
+++ b/xen/common/hypfs.c
@@ -27,22 +27,32 @@ CHECK_hypfs_dirlistentry;
const struct hypfs_funcs hypfs_dir_funcs = {
.read = hypfs_read_dir,
.write = hypfs_write_deny,
+ .getsize = hypfs_getsize,
+ .findentry = hypfs_dir_findentry,
};
const struct hypfs_funcs hypfs_leaf_ro_funcs = {
.read = hypfs_read_leaf,
.write = hypfs_write_deny,
+ .getsize = hypfs_getsize,
+ .findentry = hypfs_leaf_findentry,
};
const struct hypfs_funcs hypfs_leaf_wr_funcs = {
.read = hypfs_read_leaf,
.write = hypfs_write_leaf,
+ .getsize = hypfs_getsize,
+ .findentry = hypfs_leaf_findentry,
};
const struct hypfs_funcs hypfs_bool_wr_funcs = {
.read = hypfs_read_leaf,
.write = hypfs_write_bool,
+ .getsize = hypfs_getsize,
+ .findentry = hypfs_leaf_findentry,
};
const struct hypfs_funcs hypfs_custom_wr_funcs = {
.read = hypfs_read_leaf,
.write = hypfs_write_custom,
+ .getsize = hypfs_getsize,
+ .findentry = hypfs_leaf_findentry,
};
static DEFINE_RWLOCK(hypfs_lock);
@@ -97,6 +107,8 @@ static int add_entry(struct hypfs_entry_dir *parent, struct
hypfs_entry *new)
ASSERT(new->funcs->read);
ASSERT(new->funcs->write);
+ ASSERT(new->funcs->getsize);
+ ASSERT(new->funcs->findentry);
hypfs_write_lock();
@@ -176,15 +188,41 @@ static int hypfs_get_path_user(char *buf,
return 0;
}
+struct hypfs_entry *hypfs_leaf_findentry(const struct hypfs_entry_dir *dir,
+ const char *name,
+ unsigned int name_len)
+{
+ return ERR_PTR(-ENOTDIR);
+}
+
+struct hypfs_entry *hypfs_dir_findentry(const struct hypfs_entry_dir *dir,
+ const char *name,
+ unsigned int name_len)
+{
+ struct hypfs_entry *entry;
+
+ list_for_each_entry ( entry, &dir->dirlist, list )
+ {
+ int cmp = strncmp(name, entry->name, name_len);
+
+ if ( cmp < 0 )
+ return ERR_PTR(-ENOENT);
+
+ if ( !cmp && strlen(entry->name) == name_len )
+ return entry;
+ }
+
+ return ERR_PTR(-ENOENT);
+}
+
static struct hypfs_entry *hypfs_get_entry_rel(struct hypfs_entry_dir *dir,
const char *path)
{
const char *end;
struct hypfs_entry *entry;
unsigned int name_len;
- bool again = true;
- while ( again )
+ for ( ; ; )
{
if ( dir->e.type != XEN_HYPFS_TYPE_DIR )
return ERR_PTR(-ENOENT);
@@ -197,28 +235,12 @@ static struct hypfs_entry *hypfs_get_entry_rel(struct
hypfs_entry_dir *dir,
end = strchr(path, '\0');
name_len = end - path;
- again = false;
+ entry = dir->e.funcs->findentry(dir, path, name_len);
+ if ( IS_ERR(entry) || !*end )
+ return entry;
- list_for_each_entry ( entry, &dir->dirlist, list )
- {
- int cmp = strncmp(path, entry->name, name_len);
- struct hypfs_entry_dir *d = container_of(entry,
- struct hypfs_entry_dir,
e);
-
- if ( cmp < 0 )
- return ERR_PTR(-ENOENT);
- if ( !cmp && strlen(entry->name) == name_len )
- {
- if ( !*end )
- return entry;
-
- again = true;
- dir = d;
- path = end + 1;
-
- break;
- }
- }
+ path = end + 1;
+ dir = container_of(entry, struct hypfs_entry_dir, e);
}
return ERR_PTR(-ENOENT);
@@ -232,12 +254,17 @@ static struct hypfs_entry *hypfs_get_entry(const char
*path)
return hypfs_get_entry_rel(&hypfs_root, path + 1);
}
+unsigned int hypfs_getsize(const struct hypfs_entry *entry)
+{
+ return entry->size;
+}
+
int hypfs_read_dir(const struct hypfs_entry *entry,
XEN_GUEST_HANDLE_PARAM(void) uaddr)
{
const struct hypfs_entry_dir *d;
const struct hypfs_entry *e;
- unsigned int size = entry->size;
+ unsigned int size = entry->funcs->getsize(entry);
ASSERT(this_cpu(hypfs_locked) != hypfs_unlocked);
@@ -252,7 +279,7 @@ int hypfs_read_dir(const struct hypfs_entry *entry,
direntry.e.pad = 0;
direntry.e.type = e->type;
direntry.e.encoding = e->encoding;
- direntry.e.content_len = e->size;
+ direntry.e.content_len = e->funcs->getsize(e);
direntry.e.max_write_len = e->max_size;
direntry.off_next = list_is_last(&e->list, &d->dirlist) ? 0 : e_len;
if ( copy_to_guest(uaddr, &direntry, 1) )
@@ -275,18 +302,20 @@ int hypfs_read_leaf(const struct hypfs_entry *entry,
XEN_GUEST_HANDLE_PARAM(void) uaddr)
{
const struct hypfs_entry_leaf *l;
+ unsigned int size = entry->funcs->getsize(entry);
ASSERT(this_cpu(hypfs_locked) != hypfs_unlocked);
l = container_of(entry, const struct hypfs_entry_leaf, e);
- return copy_to_guest(uaddr, l->u.content, entry->size) ? -EFAULT: 0;
+ return copy_to_guest(uaddr, l->u.content, size) ? -EFAULT : 0;
}
static int hypfs_read(const struct hypfs_entry *entry,
XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned long ulen)
{
struct xen_hypfs_direntry e;
+ unsigned int size = entry->funcs->getsize(entry);
long ret = -EINVAL;
if ( ulen < sizeof(e) )
@@ -295,7 +324,7 @@ static int hypfs_read(const struct hypfs_entry *entry,
e.pad = 0;
e.type = entry->type;
e.encoding = entry->encoding;
- e.content_len = entry->size;
+ e.content_len = size;
e.max_write_len = entry->max_size;
ret = -EFAULT;
@@ -303,7 +332,7 @@ static int hypfs_read(const struct hypfs_entry *entry,
goto out;
ret = -ENOBUFS;
- if ( ulen < entry->size + sizeof(e) )
+ if ( ulen < size + sizeof(e) )
goto out;
guest_handle_add_offset(uaddr, sizeof(e));
@@ -319,15 +348,16 @@ int hypfs_write_leaf(struct hypfs_entry_leaf *leaf,
{
char *buf;
int ret;
+ struct hypfs_entry *e = &leaf->e;
ASSERT(this_cpu(hypfs_locked) == hypfs_write_locked);
ASSERT(leaf->e.max_size);
- if ( ulen > leaf->e.max_size )
+ if ( ulen > e->max_size )
return -ENOSPC;
- if ( leaf->e.type != XEN_HYPFS_TYPE_STRING &&
- leaf->e.type != XEN_HYPFS_TYPE_BLOB && ulen != leaf->e.size )
+ if ( e->type != XEN_HYPFS_TYPE_STRING &&
+ e->type != XEN_HYPFS_TYPE_BLOB && ulen != e->funcs->getsize(e) )
return -EDOM;
buf = xmalloc_array(char, ulen);
@@ -339,14 +369,14 @@ int hypfs_write_leaf(struct hypfs_entry_leaf *leaf,
goto out;
ret = -EINVAL;
- if ( leaf->e.type == XEN_HYPFS_TYPE_STRING &&
- leaf->e.encoding == XEN_HYPFS_ENC_PLAIN &&
+ if ( e->type == XEN_HYPFS_TYPE_STRING &&
+ e->encoding == XEN_HYPFS_ENC_PLAIN &&
memchr(buf, 0, ulen) != (buf + ulen - 1) )
goto out;
ret = 0;
memcpy(leaf->u.write_ptr, buf, ulen);
- leaf->e.size = ulen;
+ e->size = ulen;
out:
xfree(buf);
@@ -360,7 +390,7 @@ int hypfs_write_bool(struct hypfs_entry_leaf *leaf,
ASSERT(this_cpu(hypfs_locked) == hypfs_write_locked);
ASSERT(leaf->e.type == XEN_HYPFS_TYPE_BOOL &&
- leaf->e.size == sizeof(bool) &&
+ leaf->e.funcs->getsize(&leaf->e) == sizeof(bool) &&
leaf->e.max_size == sizeof(bool) );
if ( ulen != leaf->e.max_size )
diff --git a/xen/include/public/errno.h b/xen/include/public/errno.h
index e1d02fcddf..5c53af6af9 100644
--- a/xen/include/public/errno.h
+++ b/xen/include/public/errno.h
@@ -78,6 +78,7 @@ XEN_ERRNO(EBUSY, 16) /* Device or resource busy */
XEN_ERRNO(EEXIST, 17) /* File exists */
XEN_ERRNO(EXDEV, 18) /* Cross-device link */
XEN_ERRNO(ENODEV, 19) /* No such device */
+XEN_ERRNO(ENOTDIR, 20) /* Not a directory */
XEN_ERRNO(EISDIR, 21) /* Is a directory */
XEN_ERRNO(EINVAL, 22) /* Invalid argument */
XEN_ERRNO(ENFILE, 23) /* File table overflow */
diff --git a/xen/include/xen/hypfs.h b/xen/include/xen/hypfs.h
index 25fdf3ead7..53f50772b4 100644
--- a/xen/include/xen/hypfs.h
+++ b/xen/include/xen/hypfs.h
@@ -2,17 +2,21 @@
#define __XEN_HYPFS_H__
#ifdef CONFIG_HYPFS
+#include <xen/lib.h>
#include <xen/list.h>
#include <xen/string.h>
#include <public/hypfs.h>
struct hypfs_entry_leaf;
+struct hypfs_entry_dir;
struct hypfs_entry;
/*
* Per-node callbacks:
*
- * The callbacks are always called with the hypfs lock held.
+ * The callbacks are always called with the hypfs lock held. In case multiple
+ * callbacks are called for a single operation the lock is held across all
+ * those callbacks.
*
* The read() callback is used to return the contents of a node (either
* directory or leaf). It is NOT used to get directory entries during traversal
@@ -20,12 +24,24 @@ struct hypfs_entry;
*
* The write() callback is used to modify the contents of a node. Writing
* directories is not supported (this means all nodes are added at boot time).
+ *
+ * getsize() is called in two cases:
+ * - when reading a node (directory or leaf) for filling in the size of the
+ * node into the returned direntry
+ * - when reading a directory for each node in this directory
+ *
+ * findentry() is called for traversing a path from the root node to a node
+ * for all nodes on that path excluding the final node (so for looking up
+ * "/a/b/c" findentry() will be called for "/", "/a", and "/a/b").
*/
struct hypfs_funcs {
int (*read)(const struct hypfs_entry *entry,
XEN_GUEST_HANDLE_PARAM(void) uaddr);
int (*write)(struct hypfs_entry_leaf *leaf,
XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned int ulen);
+ unsigned int (*getsize)(const struct hypfs_entry *entry);
+ struct hypfs_entry *(*findentry)(const struct hypfs_entry_dir *dir,
+ const char *name, unsigned int name_len);
};
extern const struct hypfs_funcs hypfs_dir_funcs;
@@ -145,6 +161,13 @@ int hypfs_write_bool(struct hypfs_entry_leaf *leaf,
XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned int ulen);
int hypfs_write_custom(struct hypfs_entry_leaf *leaf,
XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned int ulen);
+unsigned int hypfs_getsize(const struct hypfs_entry *entry);
+struct hypfs_entry *hypfs_leaf_findentry(const struct hypfs_entry_dir *dir,
+ const char *name,
+ unsigned int name_len);
+struct hypfs_entry *hypfs_dir_findentry(const struct hypfs_entry_dir *dir,
+ const char *name,
+ unsigned int name_len);
#endif
#endif /* __XEN_HYPFS_H__ */
--
generated by git-patchbot for /home/xen/git/xen.git#staging
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