fs/gfs2/page.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
   4  *
   5  * This copyrighted material is made available to anyone wishing to use,
   6  * modify, copy, or redistribute it subject to the terms and conditions
   7  * of the GNU General Public License v.2.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/slab.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/completion.h>
  14 #include <linux/buffer_head.h>
  15 #include <linux/pagemap.h>
  16 #include <linux/mm.h>
  17 #include <linux/gfs2_ondisk.h>
  18 #include <asm/semaphore.h>
  19
  20 #include "gfs2.h"
  21 #include "lm_interface.h"
  22 #include "incore.h"
  23 #include "bmap.h"
  24 #include "inode.h"
  25 #include "page.h"
  26 #include "trans.h"
  27 #include "ops_address.h"
  28 #include "util.h"
  29
  30 /**
  31  * gfs2_pte_inval - Sync and invalidate all PTEs associated with a glock
  32  * @gl: the glock
  33  *
  34  */
  35
  36 void gfs2_pte_inval(struct gfs2_glock *gl)
  37 {
  38         struct gfs2_inode *ip;
  39         struct inode *inode;
  40
  41         ip = gl->gl_object;
  42         if (!ip || !S_ISREG(ip->i_di.di_mode))
  43                 return;
  44
  45         if (!test_bit(GIF_PAGED, &ip->i_flags))
  46                 return;
  47
  48         inode = gfs2_ip2v_lookup(ip);
  49         if (inode) {
  50                 unmap_shared_mapping_range(inode->i_mapping, 0, 0);
  51                 iput(inode);
  52
  53                 if (test_bit(GIF_SW_PAGED, &ip->i_flags))
  54                         set_bit(GLF_DIRTY, &gl->gl_flags);
  55         }
  56
  57         clear_bit(GIF_SW_PAGED, &ip->i_flags);
  58 }
  59
  60 /**
  61  * gfs2_page_inval - Invalidate all pages associated with a glock
  62  * @gl: the glock
  63  *
  64  */
  65
  66 void gfs2_page_inval(struct gfs2_glock *gl)
  67 {
  68         struct gfs2_inode *ip;
  69         struct inode *inode;
  70
  71         ip = gl->gl_object;
  72         if (!ip || !S_ISREG(ip->i_di.di_mode))
  73                 return;
  74
  75         inode = gfs2_ip2v_lookup(ip);
  76         if (inode) {
  77                 struct address_space *mapping = inode->i_mapping;
  78
  79                 truncate_inode_pages(mapping, 0);
  80                 gfs2_assert_withdraw(ip->i_sbd, !mapping->nrpages);
  81
  82                 iput(inode);
  83         }
  84
  85         clear_bit(GIF_PAGED, &ip->i_flags);
  86 }
  87
  88 /**
  89  * gfs2_page_sync - Sync the data pages (not metadata) associated with a glock
  90  * @gl: the glock
  91  * @flags: DIO_START | DIO_WAIT
  92  *
  93  * Syncs data (not metadata) for a regular file.
  94  * No-op for all other types.
  95  */
  96
  97 void gfs2_page_sync(struct gfs2_glock *gl, int flags)
  98 {
  99         struct gfs2_inode *ip;
 100         struct inode *inode;
 101
 102         ip = gl->gl_object;
 103         if (!ip || !S_ISREG(ip->i_di.di_mode))
 104                 return;
 105
 106         inode = gfs2_ip2v_lookup(ip);
 107         if (inode) {
 108                 struct address_space *mapping = inode->i_mapping;
 109                 int error = 0;
 110
 111                 if (flags & DIO_START)
 112                         filemap_fdatawrite(mapping);
 113                 if (!error && (flags & DIO_WAIT))
 114                         error = filemap_fdatawait(mapping);
 115
 116                 /* Put back any errors cleared by filemap_fdatawait()
 117                    so they can be caught by someone who can pass them
 118                    up to user space. */
 119
 120                 if (error == -ENOSPC)
 121                         set_bit(AS_ENOSPC, &mapping->flags);
 122                 else if (error)
 123                         set_bit(AS_EIO, &mapping->flags);
 124
 125                 iput(inode);
 126         }
 127 }
 128
 129 /**
 130  * gfs2_unstuffer_page - unstuff a stuffed inode into a block cached by a page
 131  * @ip: the inode
 132  * @dibh: the dinode buffer
 133  * @block: the block number that was allocated
 134  * @private: any locked page held by the caller process
 135  *
 136  * Returns: errno
 137  */
 138
 139 int gfs2_unstuffer_page(struct gfs2_inode *ip, struct buffer_head *dibh,
 140                         uint64_t block, void *private)
 141 {
 142         struct gfs2_sbd *sdp = ip->i_sbd;
 143         struct inode *inode = ip->i_vnode;
 144         struct page *page = (struct page *)private;
 145         struct buffer_head *bh;
 146         int release = 0;
 147
 148         if (!page || page->index) {
 149                 page = grab_cache_page(inode->i_mapping, 0);
 150                 if (!page)
 151                         return -ENOMEM;
 152                 release = 1;
 153         }
 154
 155         if (!PageUptodate(page)) {
 156                 void *kaddr = kmap(page);
 157
 158                 memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
 159                        ip->i_di.di_size);
 160                 memset(kaddr + ip->i_di.di_size, 0,
 161                        PAGE_CACHE_SIZE - ip->i_di.di_size);
 162                 kunmap(page);
 163
 164                 SetPageUptodate(page);
 165         }
 166
 167         if (!page_has_buffers(page))
 168                 create_empty_buffers(page, 1 << inode->i_blkbits,
 169                                      (1 << BH_Uptodate));
 170
 171         bh = page_buffers(page);
 172
 173         if (!buffer_mapped(bh))
 174                 map_bh(bh, inode->i_sb, block);
 175
 176         set_buffer_uptodate(bh);
 177         if ((sdp->sd_args.ar_data == GFS2_DATA_ORDERED) || gfs2_is_jdata(ip))
 178                 gfs2_trans_add_bh(ip->i_gl, bh, 0);
 179         mark_buffer_dirty(bh);
 180
 181         if (release) {
 182                 unlock_page(page);
 183                 page_cache_release(page);
 184         }
 185
 186         return 0;
 187 }
 188
 189 /**
 190  * gfs2_block_truncate_page - Deal with zeroing out data for truncate
 191  *
 192  * This is partly borrowed from ext3.
 193  */
 194 int gfs2_block_truncate_page(struct address_space *mapping)
 195 {
 196         struct inode *inode = mapping->host;
 197         struct gfs2_inode *ip = inode->u.generic_ip;
 198         struct gfs2_sbd *sdp = ip->i_sbd;
 199         loff_t from = inode->i_size;
 200         unsigned long index = from >> PAGE_CACHE_SHIFT;
 201         unsigned offset = from & (PAGE_CACHE_SIZE-1);
 202         unsigned blocksize, iblock, length, pos;
 203         struct buffer_head *bh;
 204         struct page *page;
 205         void *kaddr;
 206         int err;
 207
 208         page = grab_cache_page(mapping, index);
 209         if (!page)
 210                 return 0;
 211
 212         blocksize = inode->i_sb->s_blocksize;
 213         length = blocksize - (offset & (blocksize - 1));
 214         iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
 215
 216         if (!page_has_buffers(page))
 217                 create_empty_buffers(page, blocksize, 0);
 218
 219         /* Find the buffer that contains "offset" */
 220         bh = page_buffers(page);
 221         pos = blocksize;
 222         while (offset >= pos) {
 223                 bh = bh->b_this_page;
 224                 iblock++;
 225                 pos += blocksize;
 226         }
 227
 228         err = 0;
 229
 230         if (!buffer_mapped(bh)) {
 231                 gfs2_get_block(inode, iblock, bh, 0);
 232                 /* unmapped? It's a hole - nothing to do */
 233                 if (!buffer_mapped(bh))
 234                         goto unlock;
 235         }
 236
 237         /* Ok, it's mapped. Make sure it's up-to-date */
 238         if (PageUptodate(page))
 239                 set_buffer_uptodate(bh);
 240
 241         if (!buffer_uptodate(bh)) {
 242                 err = -EIO;
 243                 ll_rw_block(READ, 1, &bh);
 244                 wait_on_buffer(bh);
 245                 /* Uhhuh. Read error. Complain and punt. */
 246                 if (!buffer_uptodate(bh))
 247                         goto unlock;
 248         }
 249
 250         if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip))
 251                 gfs2_trans_add_bh(ip->i_gl, bh, 0);
 252
 253         kaddr = kmap_atomic(page, KM_USER0);
 254         memset(kaddr + offset, 0, length);
 255         flush_dcache_page(page);
 256         kunmap_atomic(kaddr, KM_USER0);
 257
 258 unlock:
 259         unlock_page(page);
 260         page_cache_release(page);
 261         return err;
 262 }
 263
 264 void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page,
 265                             unsigned int from, unsigned int to)
 266 {
 267         struct buffer_head *head = page_buffers(page);
 268         unsigned int bsize = head->b_size;
 269         struct buffer_head *bh;
 270         unsigned int start, end;
 271
 272         for (bh = head, start = 0;
 273              bh != head || !start;
 274              bh = bh->b_this_page, start = end) {
 275                 end = start + bsize;
 276                 if (end <= from || start >= to)
 277                         continue;
 278                 gfs2_trans_add_bh(ip->i_gl, bh, 0);
 279         }
 280 }
 281