From cab8d289c5ad541a5351a651d95c4086b7f84d7c Mon Sep 17 00:00:00 2001 From: Frank van der Linden Date: Tue, 23 Jun 2020 22:39:19 +0000 Subject: xattr: add a function to check if a namespace is supported Add a function that checks is an extended attribute namespace is supported for an inode, meaning that a handler must be present for either the whole namespace, or at least one synthetic xattr in the namespace. To be used by the nfs server code when being queried for extended attributes support. Cc: linux-fsdevel@vger.kernel.org Cc: Al Viro Signed-off-by: Frank van der Linden Signed-off-by: Chuck Lever --- fs/xattr.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) (limited to 'fs/xattr.c') diff --git a/fs/xattr.c b/fs/xattr.c index 95f38f57347f..386b45676d7e 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -134,6 +134,33 @@ xattr_permission(struct inode *inode, const char *name, int mask) return inode_permission(inode, mask); } +/* + * Look for any handler that deals with the specified namespace. + */ +int +xattr_supported_namespace(struct inode *inode, const char *prefix) +{ + const struct xattr_handler **handlers = inode->i_sb->s_xattr; + const struct xattr_handler *handler; + size_t preflen; + + if (!(inode->i_opflags & IOP_XATTR)) { + if (unlikely(is_bad_inode(inode))) + return -EIO; + return -EOPNOTSUPP; + } + + preflen = strlen(prefix); + + for_each_xattr_handler(handlers, handler) { + if (!strncmp(xattr_prefix(handler), prefix, preflen)) + return 0; + } + + return -EOPNOTSUPP; +} +EXPORT_SYMBOL(xattr_supported_namespace); + int __vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name, const void *value, size_t size, int flags) -- cgit v1.2.3