fs/9p: Add support user. xattr

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

6 files changed, 289 insertions, 3 deletions

diff --git a/fs/9p/Makefile b/fs/9p/Makefile
index 1a940ec7af61..91fba025fcbe 100644
--- a/fs/9p/Makefile
+++ b/fs/9p/Makefile
@@ -8,6 +8,8 @@ obj-$(CONFIG_9P_FS) := 9p.o
         vfs_dir.o \
         vfs_dentry.o \
         v9fs.o \
-        fid.o
+        fid.o  \
+        xattr.o \
+        xattr_user.o
 
 9p-$(CONFIG_9P_FSCACHE) += cache.o
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 2ac245902a4f..39352ef954dc 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -35,6 +35,7 @@
 #include <linux/idr.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
+#include <linux/xattr.h>
 #include <net/9p/9p.h>
 #include <net/9p/client.h>
 
@@ -42,6 +43,7 @@
 #include "v9fs_vfs.h"
 #include "fid.h"
 #include "cache.h"
+#include "xattr.h"
 
 static const struct inode_operations v9fs_dir_inode_operations;
 static const struct inode_operations v9fs_dir_inode_operations_dotu;
@@ -1931,6 +1933,11 @@ static const struct inode_operations v9fs_dir_inode_operations_dotl = {
         .rename = v9fs_vfs_rename,
         .getattr = v9fs_vfs_getattr_dotl,
         .setattr = v9fs_vfs_setattr_dotl,
+        .setxattr = generic_setxattr,
+        .getxattr = generic_getxattr,
+        .removexattr = generic_removexattr,
+        .listxattr = v9fs_listxattr,
+
 };
 
 static const struct inode_operations v9fs_dir_inode_operations = {
@@ -1953,6 +1960,10 @@ static const struct inode_operations v9fs_file_inode_operations = {
 static const struct inode_operations v9fs_file_inode_operations_dotl = {
         .getattr = v9fs_vfs_getattr_dotl,
         .setattr = v9fs_vfs_setattr_dotl,
+        .setxattr = generic_setxattr,
+        .getxattr = generic_getxattr,
+        .removexattr = generic_removexattr,
+        .listxattr = v9fs_listxattr,
 };
 
 static const struct inode_operations v9fs_symlink_inode_operations = {
@@ -1969,4 +1980,8 @@ static const struct inode_operations v9fs_symlink_inode_operations_dotl = {
         .put_link = v9fs_vfs_put_link,
         .getattr = v9fs_vfs_getattr_dotl,
         .setattr = v9fs_vfs_setattr_dotl,
+        .setxattr = generic_setxattr,
+        .getxattr = generic_getxattr,
+        .removexattr = generic_removexattr,
+        .listxattr = v9fs_listxattr,
 };
diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index 3623f692b448..0a2e2030c844 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -45,6 +45,7 @@
 #include "v9fs.h"
 #include "v9fs_vfs.h"
 #include "fid.h"
+#include "xattr.h"
 
 static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
 
@@ -77,9 +78,10 @@ v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
         sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
         sb->s_blocksize = 1 << sb->s_blocksize_bits;
         sb->s_magic = V9FS_MAGIC;
-        if (v9fs_proto_dotl(v9ses))
+        if (v9fs_proto_dotl(v9ses)) {
                 sb->s_op = &v9fs_super_ops_dotl;
-        else
+                sb->s_xattr = v9fs_xattr_handlers;
+        } else
                 sb->s_op = &v9fs_super_ops;
         sb->s_bdi = &v9ses->bdi;
 
diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c
new file mode 100644
index 000000000000..c434424be869
--- /dev/null
+++ b/fs/9p/xattr.c
@@ -0,0 +1,160 @@
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+
+#include "fid.h"
+#include "xattr.h"
+
+/*
+ * v9fs_xattr_get()
+ *
+ * Copy an extended attribute into the buffer
+ * provided, or compute the buffer size required.
+ * Buffer is NULL to compute the size of the buffer required.
+ *
+ * Returns a negative error number on failure, or the number of bytes
+ * used / required on success.
+ */
+ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name,
+                       void *buffer, size_t buffer_size)
+{
+        ssize_t retval;
+        int msize, read_count;
+        u64 offset = 0, attr_size;
+        struct p9_fid *fid, *attr_fid;
+
+        P9_DPRINTK(P9_DEBUG_VFS, "%s: name = %s value_len = %zu\n",
+                __func__, name, buffer_size);
+
+        fid = v9fs_fid_lookup(dentry);
+        if (IS_ERR(fid))
+                return PTR_ERR(fid);
+
+        attr_fid = p9_client_xattrwalk(fid, name, &attr_size);
+        if (IS_ERR(attr_fid)) {
+                retval = PTR_ERR(attr_fid);
+                P9_DPRINTK(P9_DEBUG_VFS,
+                        "p9_client_attrwalk failed %zd\n", retval);
+                attr_fid = NULL;
+                goto error;
+        }
+        if (!buffer_size) {
+                /* request to get the attr_size */
+                retval = attr_size;
+                goto error;
+        }
+        if (attr_size > buffer_size) {
+                retval = -ERANGE;
+                goto error;
+        }
+        msize = attr_fid->clnt->msize;
+        while (attr_size) {
+                if (attr_size > (msize - P9_IOHDRSZ))
+                        read_count = msize - P9_IOHDRSZ;
+                else
+                        read_count = attr_size;
+                read_count = p9_client_read(attr_fid, ((char *)buffer)+offset,
+                                        0, offset, read_count);
+                if (read_count < 0) {
+                        /* error in xattr read */
+                        retval = read_count;
+                        goto error;
+                }
+                offset += read_count;
+                attr_size -= read_count;
+        }
+        /* Total read xattr bytes */
+        retval = offset;
+error:
+        if (attr_fid)
+                p9_client_clunk(attr_fid);
+        return retval;
+
+}
+
+/*
+ * v9fs_xattr_set()
+ *
+ * Create, replace or remove an extended attribute for this inode. Buffer
+ * is NULL to remove an existing extended attribute, and non-NULL to
+ * either replace an existing extended attribute, or create a new extended
+ * attribute. The flags XATTR_REPLACE and XATTR_CREATE
+ * specify that an extended attribute must exist and must not exist
+ * previous to the call, respectively.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+int v9fs_xattr_set(struct dentry *dentry, const char *name,
+                   const void *value, size_t value_len, int flags)
+{
+        u64 offset = 0;
+        int retval, msize, write_count;
+        struct p9_fid *fid = NULL;
+
+        P9_DPRINTK(P9_DEBUG_VFS, "%s: name = %s value_len = %zu flags = %d\n",
+                __func__, name, value_len, flags);
+
+        fid = v9fs_fid_clone(dentry);
+        if (IS_ERR(fid)) {
+                retval = PTR_ERR(fid);
+                fid = NULL;
+                goto error;
+        }
+        /*
+         * On success fid points to xattr
+         */
+        retval = p9_client_xattrcreate(fid, name, value_len, flags);
+        if (retval < 0) {
+                P9_DPRINTK(P9_DEBUG_VFS,
+                        "p9_client_xattrcreate failed %d\n", retval);
+                goto error;
+        }
+        msize = fid->clnt->msize;;
+        while (value_len) {
+                if (value_len > (msize - P9_IOHDRSZ))
+                        write_count = msize - P9_IOHDRSZ;
+                else
+                        write_count = value_len;
+                write_count = p9_client_write(fid, ((char *)value)+offset,
+                                        0, offset, write_count);
+                if (write_count < 0) {
+                        /* error in xattr write */
+                        retval = write_count;
+                        goto error;
+                }
+                offset += write_count;
+                value_len -= write_count;
+        }
+        /* Total read xattr bytes */
+        retval = offset;
+error:
+        if (fid)
+                retval = p9_client_clunk(fid);
+        return retval;
+}
+
+ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
+{
+        return v9fs_xattr_get(dentry, NULL, buffer, buffer_size);
+}
+
+const struct xattr_handler *v9fs_xattr_handlers[] = {
+        &v9fs_xattr_user_handler,
+        NULL
+};
diff --git a/fs/9p/xattr.h b/fs/9p/xattr.h
new file mode 100644
index 000000000000..9ddf672ae5c4
--- /dev/null
+++ b/fs/9p/xattr.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+#ifndef FS_9P_XATTR_H
+#define FS_9P_XATTR_H
+
+#include <linux/xattr.h>
+
+extern const struct xattr_handler *v9fs_xattr_handlers[];
+extern struct xattr_handler v9fs_xattr_user_handler;
+
+extern ssize_t v9fs_xattr_get(struct dentry *, const char *,
+                              void *, size_t);
+extern int v9fs_xattr_set(struct dentry *, const char *,
+                          const void *, size_t, int);
+extern ssize_t v9fs_listxattr(struct dentry *, char *, size_t);
+#endif /* FS_9P_XATTR_H */
diff --git a/fs/9p/xattr_user.c b/fs/9p/xattr_user.c
new file mode 100644
index 000000000000..d0b701b72080
--- /dev/null
+++ b/fs/9p/xattr_user.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include "xattr.h"
+
+static int v9fs_xattr_user_get(struct dentry *dentry, const char *name,
+                        void *buffer, size_t size, int type)
+{
+        int retval;
+        char *full_name;
+        size_t name_len;
+        size_t prefix_len = XATTR_USER_PREFIX_LEN;
+
+        if (name == NULL)
+                return -EINVAL;
+
+        if (strcmp(name, "") == 0)
+                return -EINVAL;
+
+        name_len = strlen(name);
+        full_name = kmalloc(prefix_len + name_len + 1 , GFP_KERNEL);
+        if (!full_name)
+                return -ENOMEM;
+        memcpy(full_name, XATTR_USER_PREFIX, prefix_len);
+        memcpy(full_name+prefix_len, name, name_len);
+        full_name[prefix_len + name_len] = '\0';
+
+        retval = v9fs_xattr_get(dentry, full_name, buffer, size);
+        kfree(full_name);
+        return retval;
+}
+
+static int v9fs_xattr_user_set(struct dentry *dentry, const char *name,
+                        const void *value, size_t size, int flags, int type)
+{
+        int retval;
+        char *full_name;
+        size_t name_len;
+        size_t prefix_len = XATTR_USER_PREFIX_LEN;
+
+        if (name == NULL)
+                return -EINVAL;
+
+        if (strcmp(name, "") == 0)
+                return -EINVAL;
+
+        name_len = strlen(name);
+        full_name = kmalloc(prefix_len + name_len + 1 , GFP_KERNEL);
+        if (!full_name)
+                return -ENOMEM;
+        memcpy(full_name, XATTR_USER_PREFIX, prefix_len);
+        memcpy(full_name + prefix_len, name, name_len);
+        full_name[prefix_len + name_len] = '\0';
+
+        retval = v9fs_xattr_set(dentry, full_name, value, size, flags);
+        kfree(full_name);
+        return retval;
+}
+
+struct xattr_handler v9fs_xattr_user_handler = {
+        .prefix = XATTR_USER_PREFIX,
+        .get    = v9fs_xattr_user_get,
+        .set    = v9fs_xattr_user_set,
+};