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 /* 25 * v9fs_xattr_get() 26 * 27 * Copy an extended attribute into the buffer 28 * provided, or compute the buffer size required. 29 * Buffer is NULL to compute the size of the buffer required. 30 * 31 * Returns a negative error number on failure, or the number of bytes 32 * used / required on success. 33 */ 34 ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name, 35 void *buffer, size_t buffer_size) 36 { 37 ssize_t retval; 38 int msize, read_count; 39 u64 offset = 0, attr_size; 40 struct p9_fid *fid, *attr_fid; 41 42 P9_DPRINTK(P9_DEBUG_VFS, "%s: name = %s value_len = %zu\n", 43 __func__, name, buffer_size); 44 45 fid = v9fs_fid_lookup(dentry); 46 if (IS_ERR(fid)) 47 return PTR_ERR(fid); 48 49 attr_fid = p9_client_xattrwalk(fid, name, &attr_size); 50 if (IS_ERR(attr_fid)) { 51 retval = PTR_ERR(attr_fid); 52 P9_DPRINTK(P9_DEBUG_VFS, 53 "p9_client_attrwalk failed %zd\n", retval); 54 attr_fid = NULL; 55 goto error; 56 } 57 if (!buffer_size) { 58 /* request to get the attr_size */ 59 retval = attr_size; 60 goto error; 61 } 62 if (attr_size > buffer_size) { 63 retval = -ERANGE; 64 goto error; 65 } 66 msize = attr_fid->clnt->msize; 67 while (attr_size) { 68 if (attr_size > (msize - P9_IOHDRSZ)) 69 read_count = msize - P9_IOHDRSZ; 70 else 71 read_count = attr_size; 72 read_count = p9_client_read(attr_fid, ((char *)buffer)+offset, 73 NULL, offset, read_count); 74 if (read_count < 0) { 75 /* error in xattr read */ 76 retval = read_count; 77 goto error; 78 } 79 offset += read_count; 80 attr_size -= read_count; 81 } 82 /* Total read xattr bytes */ 83 retval = offset; 84 error: 85 if (attr_fid) 86 p9_client_clunk(attr_fid); 87 return retval; 88 89 } 90 91 /* 92 * v9fs_xattr_set() 93 * 94 * Create, replace or remove an extended attribute for this inode. Buffer 95 * is NULL to remove an existing extended attribute, and non-NULL to 96 * either replace an existing extended attribute, or create a new extended 97 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 98 * specify that an extended attribute must exist and must not exist 99 * previous to the call, respectively. 100 * 101 * Returns 0, or a negative error number on failure. 102 */ 103 int v9fs_xattr_set(struct dentry *dentry, const char *name, 104 const void *value, size_t value_len, int flags) 105 { 106 u64 offset = 0; 107 int retval, msize, write_count; 108 struct p9_fid *fid = NULL; 109 110 P9_DPRINTK(P9_DEBUG_VFS, "%s: name = %s value_len = %zu flags = %d\n", 111 __func__, name, value_len, flags); 112 113 fid = v9fs_fid_clone(dentry); 114 if (IS_ERR(fid)) { 115 retval = PTR_ERR(fid); 116 fid = NULL; 117 goto error; 118 } 119 /* 120 * On success fid points to xattr 121 */ 122 retval = p9_client_xattrcreate(fid, name, value_len, flags); 123 if (retval < 0) { 124 P9_DPRINTK(P9_DEBUG_VFS, 125 "p9_client_xattrcreate failed %d\n", retval); 126 goto error; 127 } 128 msize = fid->clnt->msize;; 129 while (value_len) { 130 if (value_len > (msize - P9_IOHDRSZ)) 131 write_count = msize - P9_IOHDRSZ; 132 else 133 write_count = value_len; 134 write_count = p9_client_write(fid, ((char *)value)+offset, 135 NULL, offset, write_count); 136 if (write_count < 0) { 137 /* error in xattr write */ 138 retval = write_count; 139 goto error; 140 } 141 offset += write_count; 142 value_len -= write_count; 143 } 144 /* Total read xattr bytes */ 145 retval = offset; 146 error: 147 if (fid) 148 retval = p9_client_clunk(fid); 149 return retval; 150 } 151 152 ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) 153 { 154 return v9fs_xattr_get(dentry, NULL, buffer, buffer_size); 155 } 156 157 const struct xattr_handler *v9fs_xattr_handlers[] = { 158 &v9fs_xattr_user_handler, 159 NULL 160 }; 161