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tmpfs: Use xattr handler infrastructure

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Use the VFS xattr handler infrastructure and get rid of similar code in
the filesystem.  For implementing shmem_xattr_handler_set, we need a
version of simple_xattr_set which removes the attribute when value is
NULL.  Use this to implement kernfs_iop_removexattr as well.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Andreas Gruenbacher 2015-12-02 14:44:38 +01:00 committed by Al Viro
parent 9172abbcd3
commit aa7c5241c3
4 changed files with 67 additions and 132 deletions
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2
fs/kernfs/inode.c
View File

@ -205,7 +205,7 @@ int kernfs_iop_removexattr(struct dentry *dentry, const char *name)
if (!attrs)
return -ENOMEM;
return simple_xattr_remove(&attrs->xattrs, name);
return simple_xattr_set(&attrs->xattrs, name, NULL, 0, XATTR_REPLACE);
}
ssize_t kernfs_iop_getxattr(struct dentry *dentry, const char *name, void *buf,

48
fs/xattr.c
View File

@ -851,8 +851,22 @@ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
return ret;
}
static int __simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
const void *value, size_t size, int flags)
/**
* simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems
* @xattrs: target simple_xattr list
* @name: name of the extended attribute
* @value: value of the xattr. If %NULL, will remove the attribute.
* @size: size of the new xattr
* @flags: %XATTR_{CREATE|REPLACE}
*
* %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails
* with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist;
* otherwise, fails with -ENODATA.
*
* Returns 0 on success, -errno on failure.
*/
int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
const void *value, size_t size, int flags)
{
struct simple_xattr *xattr;
struct simple_xattr *new_xattr = NULL;
@ -902,36 +916,6 @@ out:
}
/**
* simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems
* @xattrs: target simple_xattr list
* @name: name of the new extended attribute
* @value: value of the new xattr. If %NULL, will remove the attribute
* @size: size of the new xattr
* @flags: %XATTR_{CREATE|REPLACE}
*
* %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails
* with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist;
* otherwise, fails with -ENODATA.
*
* Returns 0 on success, -errno on failure.
*/
int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
const void *value, size_t size, int flags)
{
if (size == 0)
value = ""; /* empty EA, do not remove */
return __simple_xattr_set(xattrs, name, value, size, flags);
}
/*
* xattr REMOVE operation for in-memory/pseudo filesystems
*/
int simple_xattr_remove(struct simple_xattrs *xattrs, const char *name)
{
return __simple_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);

4
include/linux/xattr.h
View File

@ -104,9 +104,7 @@ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
void *buffer, size_t size);
int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
const void *value, size_t size, int flags);
int simple_xattr_remove(struct simple_xattrs *xattrs, const char *name);
ssize_t simple_xattr_list(struct simple_xattrs *xattrs, char *buffer,
size_t size);
ssize_t simple_xattr_list(struct simple_xattrs *xattrs, char *buffer, size_t size);
void simple_xattr_list_add(struct simple_xattrs *xattrs,
struct simple_xattr *new_xattr);

145
mm/shmem.c
View File

@ -2561,95 +2561,48 @@ static int shmem_initxattrs(struct inode *inode,
return 0;
}
static int shmem_xattr_handler_get(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
struct shmem_inode_info *info = SHMEM_I(d_inode(dentry));
name = xattr_full_name(handler, name);
return simple_xattr_get(&info->xattrs, name, buffer, size);
}
static int shmem_xattr_handler_set(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
struct shmem_inode_info *info = SHMEM_I(d_inode(dentry));
name = xattr_full_name(handler, name);
return simple_xattr_set(&info->xattrs, name, value, size, flags);
}
static const struct xattr_handler shmem_security_xattr_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.get = shmem_xattr_handler_get,
.set = shmem_xattr_handler_set,
};
static const struct xattr_handler shmem_trusted_xattr_handler = {
.prefix = XATTR_TRUSTED_PREFIX,
.get = shmem_xattr_handler_get,
.set = shmem_xattr_handler_set,
};
static const struct xattr_handler *shmem_xattr_handlers[] = {
#ifdef CONFIG_TMPFS_POSIX_ACL
&posix_acl_access_xattr_handler,
&posix_acl_default_xattr_handler,
#endif
&shmem_security_xattr_handler,
&shmem_trusted_xattr_handler,
NULL
};
static int shmem_xattr_validate(const char *name)
{
struct { const char *prefix; size_t len; } arr[] = {
{ XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN },
{ XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN }
};
int i;
for (i = 0; i < ARRAY_SIZE(arr); i++) {
size_t preflen = arr[i].len;
if (strncmp(name, arr[i].prefix, preflen) == 0) {
if (!name[preflen])
return -EINVAL;
return 0;
}
}
return -EOPNOTSUPP;
}
static ssize_t shmem_getxattr(struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
struct shmem_inode_info *info = SHMEM_I(d_inode(dentry));
int err;
/*
* If this is a request for a synthetic attribute in the system.*
* namespace use the generic infrastructure to resolve a handler
* for it via sb->s_xattr.
*/
if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
return generic_getxattr(dentry, name, buffer, size);
err = shmem_xattr_validate(name);
if (err)
return err;
return simple_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(d_inode(dentry));
int err;
/*
* If this is a request for a synthetic attribute in the system.*
* namespace use the generic infrastructure to resolve a handler
* for it via sb->s_xattr.
*/
if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
return generic_setxattr(dentry, name, value, size, flags);
err = shmem_xattr_validate(name);
if (err)
return err;
return simple_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(d_inode(dentry));
int err;
/*
* If this is a request for a synthetic attribute in the system.*
* namespace use the generic infrastructure to resolve a handler
* for it via sb->s_xattr.
*/
if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
return generic_removexattr(dentry, name);
err = shmem_xattr_validate(name);
if (err)
return err;
return simple_xattr_remove(&info->xattrs, name);
}
static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
struct shmem_inode_info *info = SHMEM_I(d_inode(dentry));
@ -2661,10 +2614,10 @@ static const struct inode_operations shmem_short_symlink_operations = {
.readlink = generic_readlink,
.follow_link = simple_follow_link,
#ifdef CONFIG_TMPFS_XATTR
.setxattr = shmem_setxattr,
.getxattr = shmem_getxattr,
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = shmem_listxattr,
.removexattr = shmem_removexattr,
.removexattr = generic_removexattr,
#endif
};
@ -2673,10 +2626,10 @@ static const struct inode_operations shmem_symlink_inode_operations = {
.follow_link = shmem_follow_link,
.put_link = shmem_put_link,
#ifdef CONFIG_TMPFS_XATTR
.setxattr = shmem_setxattr,
.getxattr = shmem_getxattr,
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = shmem_listxattr,
.removexattr = shmem_removexattr,
.removexattr = generic_removexattr,
#endif
};
@ -3148,10 +3101,10 @@ static const struct inode_operations shmem_inode_operations = {
.getattr = shmem_getattr,
.setattr = shmem_setattr,
#ifdef CONFIG_TMPFS_XATTR
.setxattr = shmem_setxattr,
.getxattr = shmem_getxattr,
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = shmem_listxattr,
.removexattr = shmem_removexattr,
.removexattr = generic_removexattr,
.set_acl = simple_set_acl,
#endif
};
@ -3170,10 +3123,10 @@ static const struct inode_operations shmem_dir_inode_operations = {
.tmpfile = shmem_tmpfile,
#endif
#ifdef CONFIG_TMPFS_XATTR
.setxattr = shmem_setxattr,
.getxattr = shmem_getxattr,
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = shmem_listxattr,
.removexattr = shmem_removexattr,
.removexattr = generic_removexattr,
#endif
#ifdef CONFIG_TMPFS_POSIX_ACL
.setattr = shmem_setattr,
@ -3183,10 +3136,10 @@ static const struct inode_operations shmem_dir_inode_operations = {
static const struct inode_operations shmem_special_inode_operations = {
#ifdef CONFIG_TMPFS_XATTR
.setxattr = shmem_setxattr,
.getxattr = shmem_getxattr,
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = shmem_listxattr,
.removexattr = shmem_removexattr,
.removexattr = generic_removexattr,
#endif
#ifdef CONFIG_TMPFS_POSIX_ACL
.setattr = shmem_setattr,