lustre/obdfs/rw.c

   1 /*
   2  * OBDFS Super operations
   3  *
   4  * Copryright (C) 1999 Stelias Computing Inc,
   5  *                (author Peter J. Braam <braam@stelias.com>)
   6  * Copryright (C) 1999 Seagate Technology Inc.
   7  */
   8
   9
  10 #include <linux/config.h>
  11 #include <linux/kernel.h>
  12 #include <linux/mm.h>
  13 #include <linux/string.h>
  14 #include <linux/stat.h>
  15 #include <linux/errno.h>
  16 #include <linux/locks.h>
  17 #include <linux/unistd.h>
  18
  19 #include <asm/system.h>
  20 #include <asm/uaccess.h>
  21
  22 #include <linux/fs.h>
  23 #include <linux/stat.h>
  24 #include <asm/uaccess.h>
  25 #include <linux/vmalloc.h>
  26 #include <asm/segment.h>
  27 #include <linux/mm.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/smp_lock.h>
  30
  31 #include <../obd/linux/obd_support.h>
  32 #include <../obd/linux/obd_sim.h>
  33 #include <obdfs.h>
  34
  35 /* VFS super_block ops */
  36
  37 /* returns the page unlocked, but with a reference */
  38 int obdfs_readpage(struct file *file, struct page *page)
  39 {
  40         struct obdfs_sb_info *sbi;
  41         struct super_block *sb = file->f_dentry->d_inode->i_sb;
  42         int rc;
  43
  44         ENTRY;
  45
  46         /* XXX flush stuff */
  47         sbi = sb->u.generic_sbp;
  48         PDEBUG(page, "READ");
  49         rc =  sbi->osi_ops->o_brw(READ, sbi->osi_conn_info.conn_id,
  50                       file->f_dentry->d_inode->i_ino, page, 0);
  51         if (rc == PAGE_SIZE ) {
  52                 SetPageUptodate(page);
  53                 UnlockPage(page);
  54         }
  55         PDEBUG(page, "READ");
  56         if ( rc == PAGE_SIZE )
  57                 rc = 0;
  58         return rc;
  59
  60 }
  61
  62 /*
  63  * This does the "real" work of the write. The generic routine has
  64  * allocated the page, locked it, done all the page alignment stuff
  65  * calculations etc. Now we should just copy the data from user
  66  * space and write it back to the real medium..
  67  *
  68  * If the writer ends up delaying the write, the writer needs to
  69  * increment the page use counts until he is done with the page.
  70  */
  71 int obdfs_write_one_page(struct file *file, struct page *page, unsigned long offset, unsigned long bytes, const char * buf)
  72 {
  73         long status;
  74         struct obdfs_sb_info *sbi = file->f_dentry->d_inode->i_sb->u.generic_sbp;
  75
  76         if ( !Page_Uptodate(page) ) {
  77                 status =  sbi->osi_ops->o_brw(READ,
  78                                               sbi->osi_conn_info.conn_id,
  79                                               file->f_dentry->d_inode->i_ino,
  80                                               page, 1);
  81                 if (status == PAGE_SIZE ) {
  82                         SetPageUptodate(page);
  83                 } else {
  84                         return status;
  85                 }
  86         }
  87         bytes -= copy_from_user((u8*)page_address(page) + offset, buf, bytes);
  88         status = -EFAULT;
  89
  90         if (bytes) {
  91                 lock_kernel();
  92                 status = obdfs_writepage(file, page);
  93                 unlock_kernel();
  94         }
  95         if ( status != PAGE_SIZE )
  96                 return status;
  97         else
  98                 return bytes;
  99 }
 100
 101
 102
 103
 104 /* returns the page unlocked, but with a reference */
 105 int obdfs_writepage(struct file *file, struct page *page)
 106 {
 107         struct obdfs_sb_info *sbi = file->f_dentry->d_inode->i_sb->u.generic_sbp;
 108         int rc;
 109
 110         ENTRY;
 111         PDEBUG(page, "WRITEPAGE");
 112         /* XXX flush stuff */
 113
 114         rc = sbi->osi_ops->o_brw(WRITE, sbi->osi_conn_info.conn_id,
 115                       file->f_dentry->d_inode->i_ino, page, 1);
 116         SetPageUptodate(page);
 117         PDEBUG(page,"WRITEPAGE");
 118         return rc;
 119 }
 120
 121
 122 /*
 123    page is returned unlocked, with the up to date flag set,
 124    and held, i.e. caller must do a page_put
 125 */
 126 struct page *obdfs_getpage(struct inode *inode, unsigned long offset, int create, int locked)
 127 {
 128         unsigned long new_page;
 129         struct page ** hash;
 130         struct page * page;
 131         struct obdfs_sb_info *sbi;
 132         struct super_block *sb = inode->i_sb;
 133
 134         ENTRY;
 135
 136         sbi = sb->u.generic_sbp;
 137
 138         page = find_lock_page(inode, offset);
 139         if (page && Page_Uptodate(page)) {
 140                 PDEBUG(page,"GETPAGE");
 141                 if (!locked)
 142                         UnlockPage(page);
 143                 return page;
 144         }
 145
 146         if (page && !Page_Uptodate(page) ) {
 147                 CDEBUG(D_INODE, "Page found but not up to date\n");
 148         }
 149
 150         /* page_cache_alloc returns address of page */
 151         new_page = page_cache_alloc();
 152         if (!new_page)
 153                 return NULL;
 154
 155         /* corresponding struct page in the mmap */
 156         hash = page_hash(inode, offset);
 157         page = page_cache_entry(new_page);
 158         PDEBUG(page, "GETPAGE");
 159         if (!add_to_page_cache_unique(page, inode, offset, hash)) {
 160                 CDEBUG(D_INODE, "Page not found. Reading it.\n");
 161                 PDEBUG(page,"GETPAGE");
 162                 sbi->osi_ops->o_brw(READ, sbi->osi_conn_info.conn_id,
 163                                     inode->i_ino, page, create);
 164                 if ( !locked )
 165                         UnlockPage(page);
 166                 SetPageUptodate(page);
 167                 PDEBUG(page,"GETPAGE");
 168                 return page;
 169         }
 170         /*
 171          * We arrive here in the unlikely event that someone
 172          * raced with us and added our page to the cache first.
 173          */
 174         CDEBUG(D_INODE, "Page not found. Someone raced us.\n");
 175         PDEBUG(page,"GETPAGE");
 176         return page;
 177 }
 178
 179
 180
 181 struct file_operations obdfs_file_ops = {
 182         NULL,                   /* lseek - default */
 183         generic_file_read,      /* read */
 184         obdfs_file_write,     /* write - bad */
 185         obdfs_readdir,          /* readdir */
 186         NULL,                   /* poll - default */
 187         NULL,                   /* ioctl */
 188         NULL,                   /* mmap */
 189         NULL,                   /* no special open code */
 190         NULL,                   /* flush */
 191         NULL,                   /* no special release code */
 192         NULL,                   /* fsync */
 193         NULL,                   /* fasync */
 194         NULL,                   /* check_media_change */
 195         NULL                    /* revalidate */
 196 };
 197
 198 struct inode_operations obdfs_inode_ops = {
 199         &obdfs_file_ops,        /* default directory file-ops */
 200         obdfs_create,   /* create */
 201         obdfs_lookup,   /* lookup */
 202         obdfs_link,     /* link */
 203         obdfs_unlink,   /* unlink */
 204         obdfs_symlink,  /* symlink */
 205         obdfs_mkdir,    /* mkdir */
 206         obdfs_rmdir,    /* rmdir */
 207         obdfs_mknod,    /* mknod */
 208         obdfs_rename,   /* rename */
 209         NULL,           /* readlink */
 210         NULL,           /* follow_link */
 211         NULL,           /* get_block */
 212         obdfs_readpage, /* readpage */
 213         obdfs_writepage, /* writepage */
 214         NULL,           /* flushpage */
 215         NULL,           /* truncate */
 216         NULL,           /* permission */
 217         NULL,           /* smap */
 218         NULL            /* revalidate */
 219 };