1 /* 2 * Copyright IBM Corporation, 2010 3 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of version 2.1 of the GNU Lesser General Public License 7 * as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it would be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 12 * 13 */ 14 15 #include <linux/module.h> 16 #include <linux/fs.h> 17 #include <linux/sched.h> 18 #include <net/9p/9p.h> 19 #include <net/9p/client.h> 20 21 #include "fid.h" 22 #include "xattr.h" 23 24 ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name, 25 void *buffer, size_t buffer_size) 26 { 27 ssize_t retval; 28 int msize, read_count; 29 u64 offset = 0, attr_size; 30 struct p9_fid *attr_fid; 31 32 attr_fid = p9_client_xattrwalk(fid, name, &attr_size); 33 if (IS_ERR(attr_fid)) { 34 retval = PTR_ERR(attr_fid); 35 p9_debug(P9_DEBUG_VFS, "p9_client_attrwalk failed %zd\n", 36 retval); 37 attr_fid = NULL; 38 goto error; 39 } 40 if (!buffer_size) { 41 /* request to get the attr_size */ 42 retval = attr_size; 43 goto error; 44 } 45 if (attr_size > buffer_size) { 46 retval = -ERANGE; 47 goto error; 48 } 49 msize = attr_fid->clnt->msize; 50 while (attr_size) { 51 if (attr_size > (msize - P9_IOHDRSZ)) 52 read_count = msize - P9_IOHDRSZ; 53 else 54 read_count = attr_size; 55 read_count = p9_client_read(attr_fid, ((char *)buffer)+offset, 56 NULL, offset, read_count); 57 if (read_count < 0) { 58 /* error in xattr read */ 59 retval = read_count; 60 goto error; 61 } 62 offset += read_count; 63 attr_size -= read_count; 64 } 65 /* Total read xattr bytes */ 66 retval = offset; 67 error: 68 if (attr_fid) 69 p9_client_clunk(attr_fid); 70 return retval; 71 72 } 73 74 75 /* 76 * v9fs_xattr_get() 77 * 78 * Copy an extended attribute into the buffer 79 * provided, or compute the buffer size required. 80 * Buffer is NULL to compute the size of the buffer required. 81 * 82 * Returns a negative error number on failure, or the number of bytes 83 * used / required on success. 84 */ 85 ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name, 86 void *buffer, size_t buffer_size) 87 { 88 struct p9_fid *fid; 89 90 p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu\n", 91 name, buffer_size); 92 fid = v9fs_fid_lookup(dentry); 93 if (IS_ERR(fid)) 94 return PTR_ERR(fid); 95 96 return v9fs_fid_xattr_get(fid, name, buffer, buffer_size); 97 } 98 99 /* 100 * v9fs_xattr_set() 101 * 102 * Create, replace or remove an extended attribute for this inode. Buffer 103 * is NULL to remove an existing extended attribute, and non-NULL to 104 * either replace an existing extended attribute, or create a new extended 105 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 106 * specify that an extended attribute must exist and must not exist 107 * previous to the call, respectively. 108 * 109 * Returns 0, or a negative error number on failure. 110 */ 111 int v9fs_xattr_set(struct dentry *dentry, const char *name, 112 const void *value, size_t value_len, int flags) 113 { 114 u64 offset = 0; 115 int retval, msize, write_count; 116 struct p9_fid *fid = NULL; 117 118 p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n", 119 name, value_len, flags); 120 121 fid = v9fs_fid_clone(dentry); 122 if (IS_ERR(fid)) { 123 retval = PTR_ERR(fid); 124 fid = NULL; 125 goto error; 126 } 127 /* 128 * On success fid points to xattr 129 */ 130 retval = p9_client_xattrcreate(fid, name, value_len, flags); 131 if (retval < 0) { 132 p9_debug(P9_DEBUG_VFS, "p9_client_xattrcreate failed %d\n", 133 retval); 134 goto error; 135 } 136 msize = fid->clnt->msize; 137 while (value_len) { 138 if (value_len > (msize - P9_IOHDRSZ)) 139 write_count = msize - P9_IOHDRSZ; 140 else 141 write_count = value_len; 142 write_count = p9_client_write(fid, ((char *)value)+offset, 143 NULL, offset, write_count); 144 if (write_count < 0) { 145 /* error in xattr write */ 146 retval = write_count; 147 goto error; 148 } 149 offset += write_count; 150 value_len -= write_count; 151 } 152 /* Total read xattr bytes */ 153 retval = offset; 154 error: 155 if (fid) 156 retval = p9_client_clunk(fid); 157 return retval; 158 } 159 160 ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) 161 { 162 return v9fs_xattr_get(dentry, NULL, buffer, buffer_size); 163 } 164 165 const struct xattr_handler *v9fs_xattr_handlers[] = { 166 &v9fs_xattr_user_handler, 167 #ifdef CONFIG_9P_FS_POSIX_ACL 168 &v9fs_xattr_acl_access_handler, 169 &v9fs_xattr_acl_default_handler, 170 #endif 171 NULL 172 }; 173