Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright details |
| 3 | */ |
| 4 | |
| 5 | #include <linux/config.h> |
| 6 | #include <linux/time.h> |
| 7 | #include <linux/pagemap.h> |
| 8 | #include <linux/buffer_head.h> |
| 9 | #include <linux/reiserfs_fs.h> |
| 10 | |
| 11 | /* access to tail : when one is going to read tail it must make sure, that is not running. |
| 12 | direct2indirect and indirect2direct can not run concurrently */ |
| 13 | |
| 14 | |
| 15 | /* Converts direct items to an unformatted node. Panics if file has no |
| 16 | tail. -ENOSPC if no disk space for conversion */ |
| 17 | /* path points to first direct item of the file regarless of how many of |
| 18 | them are there */ |
| 19 | int direct2indirect (struct reiserfs_transaction_handle *th, struct inode * inode, |
| 20 | struct path * path, struct buffer_head * unbh, |
| 21 | loff_t tail_offset) |
| 22 | { |
| 23 | struct super_block * sb = inode->i_sb; |
| 24 | struct buffer_head *up_to_date_bh ; |
| 25 | struct item_head * p_le_ih = PATH_PITEM_HEAD (path); |
| 26 | unsigned long total_tail = 0 ; |
| 27 | struct cpu_key end_key; /* Key to search for the last byte of the |
| 28 | converted item. */ |
| 29 | struct item_head ind_ih; /* new indirect item to be inserted or |
| 30 | key of unfm pointer to be pasted */ |
| 31 | int n_blk_size, |
| 32 | n_retval; /* returned value for reiserfs_insert_item and clones */ |
| 33 | unp_t unfm_ptr; /* Handle on an unformatted node |
| 34 | that will be inserted in the |
| 35 | tree. */ |
| 36 | |
| 37 | BUG_ON (!th->t_trans_id); |
| 38 | |
| 39 | REISERFS_SB(sb)->s_direct2indirect ++; |
| 40 | |
| 41 | n_blk_size = sb->s_blocksize; |
| 42 | |
| 43 | /* and key to search for append or insert pointer to the new |
| 44 | unformatted node. */ |
| 45 | copy_item_head (&ind_ih, p_le_ih); |
| 46 | set_le_ih_k_offset (&ind_ih, tail_offset); |
| 47 | set_le_ih_k_type (&ind_ih, TYPE_INDIRECT); |
| 48 | |
| 49 | /* Set the key to search for the place for new unfm pointer */ |
| 50 | make_cpu_key (&end_key, inode, tail_offset, TYPE_INDIRECT, 4); |
| 51 | |
| 52 | // FIXME: we could avoid this |
| 53 | if ( search_for_position_by_key (sb, &end_key, path) == POSITION_FOUND ) { |
| 54 | reiserfs_warning (sb, "PAP-14030: direct2indirect: " |
| 55 | "pasted or inserted byte exists in the tree %K. " |
| 56 | "Use fsck to repair.", &end_key); |
| 57 | pathrelse(path); |
| 58 | return -EIO; |
| 59 | } |
| 60 | |
| 61 | p_le_ih = PATH_PITEM_HEAD (path); |
| 62 | |
| 63 | unfm_ptr = cpu_to_le32 (unbh->b_blocknr); |
| 64 | |
| 65 | if ( is_statdata_le_ih (p_le_ih) ) { |
| 66 | /* Insert new indirect item. */ |
| 67 | set_ih_free_space (&ind_ih, 0); /* delete at nearest future */ |
| 68 | put_ih_item_len( &ind_ih, UNFM_P_SIZE ); |
| 69 | PATH_LAST_POSITION (path)++; |
| 70 | n_retval = reiserfs_insert_item (th, path, &end_key, &ind_ih, inode, |
| 71 | (char *)&unfm_ptr); |
| 72 | } else { |
| 73 | /* Paste into last indirect item of an object. */ |
| 74 | n_retval = reiserfs_paste_into_item(th, path, &end_key, inode, |
| 75 | (char *)&unfm_ptr, UNFM_P_SIZE); |
| 76 | } |
| 77 | if ( n_retval ) { |
| 78 | return n_retval; |
| 79 | } |
| 80 | |
| 81 | // note: from here there are two keys which have matching first |
| 82 | // three key components. They only differ by the fourth one. |
| 83 | |
| 84 | |
| 85 | /* Set the key to search for the direct items of the file */ |
| 86 | make_cpu_key (&end_key, inode, max_reiserfs_offset (inode), TYPE_DIRECT, 4); |
| 87 | |
| 88 | /* Move bytes from the direct items to the new unformatted node |
| 89 | and delete them. */ |
| 90 | while (1) { |
| 91 | int tail_size; |
| 92 | |
| 93 | /* end_key.k_offset is set so, that we will always have found |
| 94 | last item of the file */ |
| 95 | if ( search_for_position_by_key (sb, &end_key, path) == POSITION_FOUND ) |
| 96 | reiserfs_panic (sb, "PAP-14050: direct2indirect: " |
| 97 | "direct item (%K) not found", &end_key); |
| 98 | p_le_ih = PATH_PITEM_HEAD (path); |
| 99 | RFALSE( !is_direct_le_ih (p_le_ih), |
| 100 | "vs-14055: direct item expected(%K), found %h", |
| 101 | &end_key, p_le_ih); |
| 102 | tail_size = (le_ih_k_offset (p_le_ih) & (n_blk_size - 1)) |
| 103 | + ih_item_len(p_le_ih) - 1; |
| 104 | |
| 105 | /* we only send the unbh pointer if the buffer is not up to date. |
| 106 | ** this avoids overwriting good data from writepage() with old data |
| 107 | ** from the disk or buffer cache |
| 108 | ** Special case: unbh->b_page will be NULL if we are coming through |
| 109 | ** DIRECT_IO handler here. |
| 110 | */ |
| 111 | if (!unbh->b_page || buffer_uptodate(unbh) || PageUptodate(unbh->b_page)) { |
| 112 | up_to_date_bh = NULL ; |
| 113 | } else { |
| 114 | up_to_date_bh = unbh ; |
| 115 | } |
| 116 | n_retval = reiserfs_delete_item (th, path, &end_key, inode, |
| 117 | up_to_date_bh) ; |
| 118 | |
| 119 | total_tail += n_retval ; |
| 120 | if (tail_size == n_retval) |
| 121 | // done: file does not have direct items anymore |
| 122 | break; |
| 123 | |
| 124 | } |
| 125 | /* if we've copied bytes from disk into the page, we need to zero |
| 126 | ** out the unused part of the block (it was not up to date before) |
| 127 | */ |
| 128 | if (up_to_date_bh) { |
| 129 | unsigned pgoff = (tail_offset + total_tail - 1) & (PAGE_CACHE_SIZE - 1); |
| 130 | char *kaddr=kmap_atomic(up_to_date_bh->b_page, KM_USER0); |
| 131 | memset(kaddr + pgoff, 0, n_blk_size - total_tail) ; |
| 132 | kunmap_atomic(kaddr, KM_USER0); |
| 133 | } |
| 134 | |
| 135 | REISERFS_I(inode)->i_first_direct_byte = U32_MAX; |
| 136 | |
| 137 | return 0; |
| 138 | } |
| 139 | |
| 140 | |
| 141 | /* stolen from fs/buffer.c */ |
| 142 | void reiserfs_unmap_buffer(struct buffer_head *bh) { |
| 143 | lock_buffer(bh) ; |
| 144 | if (buffer_journaled(bh) || buffer_journal_dirty(bh)) { |
| 145 | BUG() ; |
| 146 | } |
| 147 | clear_buffer_dirty(bh) ; |
| 148 | /* Remove the buffer from whatever list it belongs to. We are mostly |
| 149 | interested in removing it from per-sb j_dirty_buffers list, to avoid |
| 150 | BUG() on attempt to write not mapped buffer */ |
| 151 | if ( (!list_empty(&bh->b_assoc_buffers) || bh->b_private) && bh->b_page) { |
| 152 | struct inode *inode = bh->b_page->mapping->host; |
| 153 | struct reiserfs_journal *j = SB_JOURNAL(inode->i_sb); |
| 154 | spin_lock(&j->j_dirty_buffers_lock); |
| 155 | list_del_init(&bh->b_assoc_buffers); |
| 156 | reiserfs_free_jh(bh); |
| 157 | spin_unlock(&j->j_dirty_buffers_lock); |
| 158 | } |
| 159 | clear_buffer_mapped(bh) ; |
| 160 | clear_buffer_req(bh) ; |
| 161 | clear_buffer_new(bh); |
| 162 | bh->b_bdev = NULL; |
| 163 | unlock_buffer(bh) ; |
| 164 | } |
| 165 | |
| 166 | /* this first locks inode (neither reads nor sync are permitted), |
| 167 | reads tail through page cache, insert direct item. When direct item |
| 168 | inserted successfully inode is left locked. Return value is always |
| 169 | what we expect from it (number of cut bytes). But when tail remains |
| 170 | in the unformatted node, we set mode to SKIP_BALANCING and unlock |
| 171 | inode */ |
| 172 | int indirect2direct (struct reiserfs_transaction_handle *th, |
| 173 | struct inode * p_s_inode, |
| 174 | struct page *page, |
| 175 | struct path * p_s_path, /* path to the indirect item. */ |
| 176 | const struct cpu_key * p_s_item_key, /* Key to look for unformatted node pointer to be cut. */ |
| 177 | loff_t n_new_file_size, /* New file size. */ |
| 178 | char * p_c_mode) |
| 179 | { |
| 180 | struct super_block * p_s_sb = p_s_inode->i_sb; |
| 181 | struct item_head s_ih; |
| 182 | unsigned long n_block_size = p_s_sb->s_blocksize; |
| 183 | char * tail; |
| 184 | int tail_len, round_tail_len; |
| 185 | loff_t pos, pos1; /* position of first byte of the tail */ |
| 186 | struct cpu_key key; |
| 187 | |
| 188 | BUG_ON (!th->t_trans_id); |
| 189 | |
| 190 | REISERFS_SB(p_s_sb)->s_indirect2direct ++; |
| 191 | |
| 192 | *p_c_mode = M_SKIP_BALANCING; |
| 193 | |
| 194 | /* store item head path points to. */ |
| 195 | copy_item_head (&s_ih, PATH_PITEM_HEAD(p_s_path)); |
| 196 | |
| 197 | tail_len = (n_new_file_size & (n_block_size - 1)); |
| 198 | if (get_inode_sd_version (p_s_inode) == STAT_DATA_V2) |
| 199 | round_tail_len = ROUND_UP (tail_len); |
| 200 | else |
| 201 | round_tail_len = tail_len; |
| 202 | |
| 203 | pos = le_ih_k_offset (&s_ih) - 1 + (ih_item_len(&s_ih) / UNFM_P_SIZE - 1) * p_s_sb->s_blocksize; |
| 204 | pos1 = pos; |
| 205 | |
| 206 | // we are protected by i_sem. The tail can not disapper, not |
| 207 | // append can be done either |
| 208 | // we are in truncate or packing tail in file_release |
| 209 | |
| 210 | tail = (char *)kmap(page) ; /* this can schedule */ |
| 211 | |
| 212 | if (path_changed (&s_ih, p_s_path)) { |
| 213 | /* re-search indirect item */ |
| 214 | if ( search_for_position_by_key (p_s_sb, p_s_item_key, p_s_path) == POSITION_NOT_FOUND ) |
| 215 | reiserfs_panic(p_s_sb, "PAP-5520: indirect2direct: " |
| 216 | "item to be converted %K does not exist", p_s_item_key); |
| 217 | copy_item_head(&s_ih, PATH_PITEM_HEAD(p_s_path)); |
| 218 | #ifdef CONFIG_REISERFS_CHECK |
| 219 | pos = le_ih_k_offset (&s_ih) - 1 + |
| 220 | (ih_item_len(&s_ih) / UNFM_P_SIZE - 1) * p_s_sb->s_blocksize; |
| 221 | if (pos != pos1) |
| 222 | reiserfs_panic (p_s_sb, "vs-5530: indirect2direct: " |
| 223 | "tail position changed while we were reading it"); |
| 224 | #endif |
| 225 | } |
| 226 | |
| 227 | |
| 228 | /* Set direct item header to insert. */ |
| 229 | make_le_item_head (&s_ih, NULL, get_inode_item_key_version (p_s_inode), pos1 + 1, |
| 230 | TYPE_DIRECT, round_tail_len, 0xffff/*ih_free_space*/); |
| 231 | |
| 232 | /* we want a pointer to the first byte of the tail in the page. |
| 233 | ** the page was locked and this part of the page was up to date when |
| 234 | ** indirect2direct was called, so we know the bytes are still valid |
| 235 | */ |
| 236 | tail = tail + (pos & (PAGE_CACHE_SIZE - 1)) ; |
| 237 | |
| 238 | PATH_LAST_POSITION(p_s_path)++; |
| 239 | |
| 240 | key = *p_s_item_key; |
| 241 | set_cpu_key_k_type (&key, TYPE_DIRECT); |
| 242 | key.key_length = 4; |
| 243 | /* Insert tail as new direct item in the tree */ |
| 244 | if ( reiserfs_insert_item(th, p_s_path, &key, &s_ih, p_s_inode, |
| 245 | tail ? tail : NULL) < 0 ) { |
| 246 | /* No disk memory. So we can not convert last unformatted node |
| 247 | to the direct item. In this case we used to adjust |
| 248 | indirect items's ih_free_space. Now ih_free_space is not |
| 249 | used, it would be ideal to write zeros to corresponding |
| 250 | unformatted node. For now i_size is considered as guard for |
| 251 | going out of file size */ |
| 252 | kunmap(page) ; |
| 253 | return n_block_size - round_tail_len; |
| 254 | } |
| 255 | kunmap(page) ; |
| 256 | |
| 257 | /* make sure to get the i_blocks changes from reiserfs_insert_item */ |
| 258 | reiserfs_update_sd(th, p_s_inode); |
| 259 | |
| 260 | // note: we have now the same as in above direct2indirect |
| 261 | // conversion: there are two keys which have matching first three |
| 262 | // key components. They only differ by the fouhth one. |
| 263 | |
| 264 | /* We have inserted new direct item and must remove last |
| 265 | unformatted node. */ |
| 266 | *p_c_mode = M_CUT; |
| 267 | |
| 268 | /* we store position of first direct item in the in-core inode */ |
| 269 | //mark_file_with_tail (p_s_inode, pos1 + 1); |
| 270 | REISERFS_I(p_s_inode)->i_first_direct_byte = pos1 + 1; |
| 271 | |
| 272 | return n_block_size - round_tail_len; |
| 273 | } |
| 274 | |
| 275 | |
| 276 | |