[PATCH v2 1/3] xattr: extract kmem_xattr code from tmpfs
From: Li Zefan
Date: Thu Mar 01 2012 - 01:15:28 EST
Extract in-memory xattr APIs from tmpfs. Will be used by cgroup.
$ size vmlinux.o
text data bss dec hex filename
5480650 655744 7039512 13175906 c90c62 vmlinux.o
$ size vmlinux.o
text data bss dec hex filename
5480427 655744 7039448 13175619 c90b43 vmlinux.o
Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
---
fs/xattr.c | 167 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/shmem_fs.h | 3 +-
include/linux/xattr.h | 23 ++++++
mm/shmem.c | 151 +++--------------------------------------
4 files changed, 202 insertions(+), 142 deletions(-)
diff --git a/fs/xattr.c b/fs/xattr.c
index 82f4337..8af1b7f 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -757,3 +757,170 @@ EXPORT_SYMBOL(generic_getxattr);
EXPORT_SYMBOL(generic_listxattr);
EXPORT_SYMBOL(generic_setxattr);
EXPORT_SYMBOL(generic_removexattr);
+
+/*
+ * initialize the kmem_xattrs structure
+ */
+void kmem_xattrs_init(struct kmem_xattrs *xattrs)
+{
+ INIT_LIST_HEAD(&xattrs->head);
+ spin_lock_init(&xattrs->lock);
+}
+
+/*
+ * free all the xattrs
+ */
+void kmem_xattrs_free(struct kmem_xattrs *xattrs)
+{
+ struct kmem_xattr *xattr, *node;
+
+ spin_lock(&xattrs->lock);
+ list_for_each_entry_safe(xattr, node, &xattrs->head, list) {
+ kfree(xattr->name);
+ kfree(xattr);
+ }
+ spin_unlock(&xattrs->lock);
+}
+
+/*
+ * xattr GET operation for in-memory/pseudo filesystems
+ */
+int kmem_xattr_get(struct kmem_xattrs *xattrs, const char *name,
+ void *buffer, size_t size)
+{
+ struct kmem_xattr *xattr;
+ int ret = -ENODATA;
+
+ spin_lock(&xattrs->lock);
+ list_for_each_entry(xattr, &xattrs->head, list) {
+ if (strcmp(name, xattr->name))
+ continue;
+
+ ret = xattr->size;
+ if (buffer) {
+ if (size < xattr->size)
+ ret = -ERANGE;
+ else
+ memcpy(buffer, xattr->value, xattr->size);
+ }
+ break;
+ }
+ spin_unlock(&xattrs->lock);
+ return ret;
+}
+
+static int __kmem_xattr_set(struct kmem_xattrs *xattrs, const char *name,
+ const void *value, size_t size, int flags)
+{
+ struct kmem_xattr *xattr;
+ struct kmem_xattr *new_xattr = NULL;
+ size_t len;
+ int err = 0;
+
+ /* value == NULL means remove */
+ if (value) {
+ /* wrap around? */
+ len = sizeof(*new_xattr) + size;
+ if (len <= sizeof(*new_xattr))
+ return -ENOMEM;
+
+ new_xattr = kmalloc(len, GFP_KERNEL);
+ if (!new_xattr)
+ return -ENOMEM;
+
+ new_xattr->name = kstrdup(name, GFP_KERNEL);
+ if (!new_xattr->name) {
+ kfree(new_xattr);
+ return -ENOMEM;
+ }
+
+ new_xattr->size = size;
+ memcpy(new_xattr->value, value, size);
+ }
+
+ spin_lock(&xattrs->lock);
+ list_for_each_entry(xattr, &xattrs->head, list) {
+ if (!strcmp(name, xattr->name)) {
+ if (flags & XATTR_CREATE) {
+ xattr = new_xattr;
+ err = -EEXIST;
+ } else if (new_xattr) {
+ list_replace(&xattr->list, &new_xattr->list);
+ } else {
+ list_del(&xattr->list);
+ }
+ goto out;
+ }
+ }
+ if (flags & XATTR_REPLACE) {
+ xattr = new_xattr;
+ err = -ENODATA;
+ } else {
+ list_add(&new_xattr->list, &xattrs->head);
+ xattr = NULL;
+ }
+out:
+ spin_unlock(&xattrs->lock);
+ if (xattr)
+ kfree(xattr->name);
+ kfree(xattr);
+ return err;
+
+}
+
+/*
+ * xattr SET operation for in-memory/pseudo filesystems
+ */
+int kmem_xattr_set(struct kmem_xattrs *xattrs, const char *name,
+ const void *value, size_t size, int flags)
+{
+ if (size == 0)
+ value = ""; /* empty EA, do not remove */
+ return __kmem_xattr_set(xattrs, name, value, size, flags);
+}
+
+/*
+ * xattr REMOVE operation for in-memory/pseudo filesystems
+ */
+int kmem_xattr_remove(struct kmem_xattrs *xattrs, const char *name)
+{
+ return __kmem_xattr_set(xattrs, name, NULL, 0, XATTR_REPLACE);
+}
+
+static bool xattr_is_trusted(const char *name)
+{
+ return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
+}
+
+/*
+ * xattr LIST operation for in-memory/pseudo filesystems
+ */
+ssize_t kmem_xattr_list(struct kmem_xattrs *xattrs, char *buffer, size_t size)
+{
+ bool trusted = capable(CAP_SYS_ADMIN);
+ struct kmem_xattr *xattr;
+ size_t used = 0;
+
+ spin_lock(&xattrs->lock);
+ list_for_each_entry(xattr, &xattrs->head, list) {
+ size_t len;
+
+ /* skip "trusted." attributes for unprivileged callers */
+ if (!trusted && xattr_is_trusted(xattr->name))
+ continue;
+
+ len = strlen(xattr->name) + 1;
+ used += len;
+ if (buffer) {
+ if (size < used) {
+ used = -ERANGE;
+ break;
+ }
+ memcpy(buffer, xattr->name, len);
+ buffer += len;
+ }
+ }
+ spin_unlock(&xattrs->lock);
+
+ return used;
+}
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index e4c711c..6d006b6 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -5,6 +5,7 @@
#include <linux/mempolicy.h>
#include <linux/pagemap.h>
#include <linux/percpu_counter.h>
+#include <linux/xattr.h>
/* inode in-kernel data */
@@ -18,7 +19,7 @@ struct shmem_inode_info {
};
struct shared_policy policy; /* NUMA memory alloc policy */
struct list_head swaplist; /* chain of maybes on swap */
- struct list_head xattr_list; /* list of shmem_xattr */
+ struct kmem_xattrs xattrs; /* list of xattrs */
struct inode vfs_inode;
};
diff --git a/include/linux/xattr.h b/include/linux/xattr.h
index e5d1220..4d07f97 100644
--- a/include/linux/xattr.h
+++ b/include/linux/xattr.h
@@ -60,6 +60,7 @@
#ifdef __KERNEL__
#include <linux/types.h>
+#include <linux/spinlock.h>
struct inode;
struct dentry;
@@ -96,6 +97,28 @@ ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
char **xattr_value, size_t size, gfp_t flags);
int vfs_xattr_cmp(struct dentry *dentry, const char *xattr_name,
const char *value, size_t size, gfp_t flags);
+
+struct kmem_xattrs {
+ struct list_head head;
+ spinlock_t lock;
+};
+
+struct kmem_xattr {
+ struct list_head list;
+ char *name;
+ size_t size;
+ char value[0];
+};
+
+void kmem_xattrs_init(struct kmem_xattrs *xattrs);
+void kmem_xattrs_free(struct kmem_xattrs *xattrs);
+int kmem_xattr_get(struct kmem_xattrs *xattrs, const char *name,
+ void *buffer, size_t size);
+int kmem_xattr_set(struct kmem_xattrs *xattrs, const char *name,
+ const void *value, size_t size, int flags);
+int kmem_xattr_remove(struct kmem_xattrs *xattrs, const char *name);
+ssize_t kmem_xattr_list(struct kmem_xattrs *xattrs, char *buffer, size_t size);
+
#endif /* __KERNEL__ */
#endif /* _LINUX_XATTR_H */
diff --git a/mm/shmem.c b/mm/shmem.c
index feead19..2e1e416 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -76,13 +76,6 @@ static struct vfsmount *shm_mnt;
/* Symlink up to this size is kmalloc'ed instead of using a swappable page */
#define SHORT_SYMLINK_LEN 128
-struct shmem_xattr {
- struct list_head list; /* anchored by shmem_inode_info->xattr_list */
- char *name; /* xattr name */
- size_t size;
- char value[0];
-};
-
/* Flag allocation requirements to shmem_getpage */
enum sgp_type {
SGP_READ, /* don't exceed i_size, don't allocate page */
@@ -545,7 +538,6 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr)
static void shmem_evict_inode(struct inode *inode)
{
struct shmem_inode_info *info = SHMEM_I(inode);
- struct shmem_xattr *xattr, *nxattr;
if (inode->i_mapping->a_ops == &shmem_aops) {
shmem_unacct_size(info->flags, inode->i_size);
@@ -559,10 +551,7 @@ static void shmem_evict_inode(struct inode *inode)
} else
kfree(info->symlink);
- list_for_each_entry_safe(xattr, nxattr, &info->xattr_list, list) {
- kfree(xattr->name);
- kfree(xattr);
- }
+ kmem_xattrs_free(&info->xattrs);
BUG_ON(inode->i_blocks);
shmem_free_inode(inode->i_sb);
end_writeback(inode);
@@ -1114,7 +1103,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode
spin_lock_init(&info->lock);
info->flags = flags & VM_NORESERVE;
INIT_LIST_HEAD(&info->swaplist);
- INIT_LIST_HEAD(&info->xattr_list);
+ kmem_xattrs_init(&info->xattrs);
cache_no_acl(inode);
switch (mode & S_IFMT) {
@@ -1679,93 +1668,6 @@ static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *co
* filesystem level, though.
*/
-static int shmem_xattr_get(struct dentry *dentry, const char *name,
- void *buffer, size_t size)
-{
- struct shmem_inode_info *info;
- struct shmem_xattr *xattr;
- int ret = -ENODATA;
-
- info = SHMEM_I(dentry->d_inode);
-
- spin_lock(&info->lock);
- list_for_each_entry(xattr, &info->xattr_list, list) {
- if (strcmp(name, xattr->name))
- continue;
-
- ret = xattr->size;
- if (buffer) {
- if (size < xattr->size)
- ret = -ERANGE;
- else
- memcpy(buffer, xattr->value, xattr->size);
- }
- break;
- }
- spin_unlock(&info->lock);
- return ret;
-}
-
-static int shmem_xattr_set(struct dentry *dentry, const char *name,
- const void *value, size_t size, int flags)
-{
- struct inode *inode = dentry->d_inode;
- struct shmem_inode_info *info = SHMEM_I(inode);
- struct shmem_xattr *xattr;
- struct shmem_xattr *new_xattr = NULL;
- size_t len;
- int err = 0;
-
- /* value == NULL means remove */
- if (value) {
- /* wrap around? */
- len = sizeof(*new_xattr) + size;
- if (len <= sizeof(*new_xattr))
- return -ENOMEM;
-
- new_xattr = kmalloc(len, GFP_KERNEL);
- if (!new_xattr)
- return -ENOMEM;
-
- new_xattr->name = kstrdup(name, GFP_KERNEL);
- if (!new_xattr->name) {
- kfree(new_xattr);
- return -ENOMEM;
- }
-
- new_xattr->size = size;
- memcpy(new_xattr->value, value, size);
- }
-
- spin_lock(&info->lock);
- list_for_each_entry(xattr, &info->xattr_list, list) {
- if (!strcmp(name, xattr->name)) {
- if (flags & XATTR_CREATE) {
- xattr = new_xattr;
- err = -EEXIST;
- } else if (new_xattr) {
- list_replace(&xattr->list, &new_xattr->list);
- } else {
- list_del(&xattr->list);
- }
- goto out;
- }
- }
- if (flags & XATTR_REPLACE) {
- xattr = new_xattr;
- err = -ENODATA;
- } else {
- list_add(&new_xattr->list, &info->xattr_list);
- xattr = NULL;
- }
-out:
- spin_unlock(&info->lock);
- if (xattr)
- kfree(xattr->name);
- kfree(xattr);
- return err;
-}
-
static const struct xattr_handler *shmem_xattr_handlers[] = {
#ifdef CONFIG_TMPFS_POSIX_ACL
&generic_acl_access_handler,
@@ -1796,6 +1698,7 @@ static int shmem_xattr_validate(const char *name)
static ssize_t shmem_getxattr(struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
+ struct shmem_inode_info *info = SHMEM_I(dentry->d_inode);
int err;
/*
@@ -1810,12 +1713,13 @@ static ssize_t shmem_getxattr(struct dentry *dentry, const char *name,
if (err)
return err;
- return shmem_xattr_get(dentry, name, buffer, size);
+ return kmem_xattr_get(&info->xattrs, name, buffer, size);
}
static int shmem_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
+ struct shmem_inode_info *info = SHMEM_I(dentry->d_inode);
int err;
/*
@@ -1830,15 +1734,12 @@ static int shmem_setxattr(struct dentry *dentry, const char *name,
if (err)
return err;
- if (size == 0)
- value = ""; /* empty EA, do not remove */
-
- return shmem_xattr_set(dentry, name, value, size, flags);
-
+ return kmem_xattr_set(&info->xattrs, name, value, size, flags);
}
static int shmem_removexattr(struct dentry *dentry, const char *name)
{
+ struct shmem_inode_info *info = SHMEM_I(dentry->d_inode);
int err;
/*
@@ -1853,45 +1754,13 @@ static int shmem_removexattr(struct dentry *dentry, const char *name)
if (err)
return err;
- return shmem_xattr_set(dentry, name, NULL, 0, XATTR_REPLACE);
-}
-
-static bool xattr_is_trusted(const char *name)
-{
- return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
+ return kmem_xattr_remove(&info->xattrs, name);
}
static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
- bool trusted = capable(CAP_SYS_ADMIN);
- struct shmem_xattr *xattr;
- struct shmem_inode_info *info;
- size_t used = 0;
-
- info = SHMEM_I(dentry->d_inode);
-
- spin_lock(&info->lock);
- list_for_each_entry(xattr, &info->xattr_list, list) {
- size_t len;
-
- /* skip "trusted." attributes for unprivileged callers */
- if (!trusted && xattr_is_trusted(xattr->name))
- continue;
-
- len = strlen(xattr->name) + 1;
- used += len;
- if (buffer) {
- if (size < used) {
- used = -ERANGE;
- break;
- }
- memcpy(buffer, xattr->name, len);
- buffer += len;
- }
- }
- spin_unlock(&info->lock);
-
- return used;
+ struct shmem_inode_info *info = SHMEM_I(dentry->d_inode);
+ return kmem_xattr_list(&info->xattrs, buffer, size);
}
#endif /* CONFIG_TMPFS_XATTR */
--
1.7.3.1
--
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