lustre/obdclass/proc_lustre.c

   1 /* proc_lustre.c manages /proc/lustre/obd.
   2  *
   3  * Copyright (c) 2001 Rumi Zahir <rumi.zahir@intel.com>
   4  *
   5  * This code is issued under the GNU General Public License.
   6  * See the file COPYING in this distribution
   7  *
   8  * OBD devices materialize in /proc as a directory:
   9  *              /proc/lustre/obd/<number>
  10  * when /dev/obd<number> is opened. When the device is closed, the
  11  * directory entry disappears.
  12  *
  13  * For each open OBD device, code in this file also creates a file
  14  * named <status>. "cat /proc/lustre/obd/<number>/status" gives
  15  * information about the OBD device's configuration.
  16  * The class driver manages the "status" entry.
  17  *
  18  * Other logical drivers can create their own entries. For example,
  19  * the obdtrace driver creates /proc/lustre/obd/<obdid>/stats entry.
  20  *
  21  * This file defines three functions
  22  *               proc_lustre_register_obd_device()
  23  *               proc_lustre_release_obd_device()
  24  *               proc_lustre_remove_obd_entry()
  25  * that dynamically create/delete /proc/lustre/obd entries:
  26  *
  27  *     proc_lustre_register_obd_device() registers an obd device,
  28  *     and, if this is the first OBD device, creates /proc/lustre/obd.
  29  *
  30  *     proc_lustre_release_obd_device() removes device information
  31  *     from /proc/lustre/obd, and if this is the last OBD device
  32  *     removes  /proc/lustre/obd.
  33  *
  34  *     proc_lustre_remove_obd_entry() removes a
  35  *     /proc/lustre/obd/<obdid>/ entry by name. This is the only
  36  *     function that is exported to other modules.
  37  */
  38
  39 #define EXPORT_SYMTAB
  40 #include <linux/config.h>
  41 #include <linux/module.h>
  42 #include <linux/version.h>
  43 #include <linux/proc_fs.h>
  44
  45 #define DEBUG_SUBSYSTEM S_CLASS
  46
  47 #include <linux/obd_support.h>
  48 #include <linux/obd_class.h>
  49
  50 #ifdef CONFIG_PROC_FS
  51 extern struct proc_dir_entry proc_root;
  52
  53 static struct proc_dir_entry *proc_lustre_dir_entry = 0;
  54 static struct proc_dir_entry *proc_lustre_obd_dir_entry = 0;
  55
  56 static struct proc_dir_entry *
  57 proc_lustre_mkdir(const char* dname, struct proc_dir_entry *parent)
  58 {
  59         struct proc_dir_entry *child_dir_entry;
  60
  61 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,3,0)  /*0x20300 */
  62         child_dir_entry = proc_mkdir(dname, parent);
  63 #else
  64         child_dir_entry = create_proc_entry(dname,
  65                                             S_IFDIR | S_IRUGO | S_IXUGO,
  66                                             &proc_root);
  67 #endif
  68         if (!child_dir_entry)
  69                 CERROR("lustre: failed to create /proc entry %s\n", dname);
  70
  71         return child_dir_entry;
  72 }
  73
  74 static int read_lustre_status(char *page, char **start, off_t offset,
  75                               int count, int *eof, void *data)
  76 {
  77         struct obd_device * obddev = (struct obd_device *) data;
  78         int p;
  79
  80         p = sprintf(&page[0], "/dev/obd%d: ", obddev->obd_minor);
  81
  82         if  (obddev->obd_flags & OBD_ATTACHED) {
  83                 p += sprintf(&page[p], ", attached(%s)",
  84                              obddev->obd_type->typ_name);
  85         }
  86
  87         if  (obddev->obd_flags & OBD_SET_UP) {
  88                 struct dentry   *my_dentry;
  89                 struct vfsmount *root_mnt;
  90                 char *path;
  91                 char *pathpage;
  92
  93                 if (!(pathpage = (char*) __get_free_page(GFP_KERNEL)))
  94                         return -ENOMEM;
  95
  96                 my_dentry = NULL;
  97                 root_mnt = mntget(current->fs->rootmnt);
  98                 path = d_path(my_dentry,root_mnt,pathpage,PAGE_SIZE);
  99
 100                 p += sprintf(&page[p], ", setup(%s)", path);
 101
 102                 free_page((unsigned long) pathpage);
 103         }
 104
 105         /* print connections */
 106         {
 107                 struct list_head * lh;
 108                 struct obd_export * export=0;
 109
 110                 lh = &obddev->obd_exports;
 111                 while ((lh = lh->next) != &obddev->obd_exports) {
 112                         p += sprintf(&page[p],
 113                                      ((export==0) ? ", connections(" : ",") );
 114                         export = list_entry(lh, struct obd_export, export_chain);
 115                         p += sprintf(&page[p], "%d", export->export_id);
 116                 } /* while */
 117                 if (export!=0) { /* there was at least one export */
 118                         p += sprintf(&page[p], ")");
 119                 }
 120         }
 121
 122         p += sprintf(&page[p], "\n");
 123
 124         /* Compute eof and return value */
 125
 126         if (offset + count >= p) {
 127                 *eof=1;
 128                 return (p - offset);
 129         }
 130         return count;
 131 }
 132
 133 struct proc_dir_entry *
 134 proc_lustre_register_obd_device(struct obd_device *obd)
 135 {
 136         char obdname[32];
 137         struct proc_dir_entry *obd_dir;
 138         struct proc_dir_entry *obd_status = 0;
 139
 140         if (!proc_lustre_dir_entry) {
 141                 proc_lustre_dir_entry =
 142                         proc_lustre_mkdir("lustre", &proc_root);
 143                 if (!proc_lustre_dir_entry)
 144                         return 0;
 145
 146                 proc_lustre_obd_dir_entry =
 147                         proc_lustre_mkdir("obd", proc_lustre_dir_entry);
 148                 if (!proc_lustre_obd_dir_entry)
 149                         return 0;
 150         }
 151
 152         sprintf(obdname, "%d", obd->obd_minor);
 153
 154         obd_dir =  proc_lustre_mkdir(obdname, proc_lustre_obd_dir_entry);
 155
 156         if (obd_dir)
 157                 obd_status = create_proc_entry("status", S_IRUSR | S_IFREG, obd_dir);
 158
 159         if (obd_status) {
 160                 obd_status->read_proc = read_lustre_status;
 161                 obd_status->data = (void*) obd;
 162         }
 163
 164         return obd_dir;
 165 }
 166
 167 void proc_lustre_remove_obd_entry(const char* name, struct obd_device *obd)
 168 {
 169         struct proc_dir_entry *obd_entry = 0;
 170         struct proc_dir_entry *obd_dir = obd->obd_proc_entry;
 171
 172         remove_proc_entry(name, obd_dir);
 173
 174         while (obd_dir->subdir==0) {
 175                 /* if we removed last entry in this directory,
 176                  * then remove parent directory unless this
 177                  * is /proc itself
 178                  */
 179                 if (obd_dir == &proc_root)
 180                         break;
 181
 182                 obd_entry = obd_dir;
 183                 obd_dir = obd_dir->parent;
 184
 185                 /* If /proc/lustre/obd/foo or /proc/lustre/obd or
 186                  * /proc/lustre is being removed, then reset
 187                  * internal variables
 188                  */
 189
 190                 if (obd_entry == obd->obd_proc_entry)
 191                         obd->obd_proc_entry=0; /* /proc/lustre/obd/foo */
 192                 else
 193                         if (obd_entry == proc_lustre_obd_dir_entry)
 194                                 proc_lustre_obd_dir_entry=0;
 195                         else
 196                                 if (obd_entry == proc_lustre_dir_entry)
 197                                         proc_lustre_dir_entry=0;
 198
 199                 remove_proc_entry(obd_entry->name, obd_dir);
 200         }
 201 }
 202
 203 void proc_lustre_release_obd_device(struct obd_device *obd)
 204 {
 205         proc_lustre_remove_obd_entry("status", obd);
 206 }
 207
 208
 209 #else  /* CONFIG_PROC_FS */
 210
 211 struct proc_dir_entry *proc_lustre_register_obd_device(struct obd_device *obd)
 212 {
 213         return 0;
 214 }
 215
 216 void proc_lustre_remove_obd_entry(const char* name, struct obd_device *obd) {}
 217 void proc_lustre_release_obd_device(struct obd_device *obd) {}
 218
 219 #endif   /* CONFIG_PROC_FS */
 220
 221 EXPORT_SYMBOL(proc_lustre_remove_obd_entry);
 222
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