2 * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
6 * Copyright (c) 2012 Martin Sucha
7 * Copyright (c) 2012 Frantisek Princ
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
14 * - Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * - Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * - The name of the author may not be used to endorse or promote products
20 * derived from this software without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 /** @addtogroup lwext4
39 * @brief Inode allocation procedures.
42 #include "ext4_config.h"
43 #include "ext4_types.h"
44 #include "ext4_ialloc.h"
45 #include "ext4_super.h"
46 #include "ext4_crc32c.h"
48 #include "ext4_blockdev.h"
49 #include "ext4_block_group.h"
50 #include "ext4_bitmap.h"
52 /**@brief Convert i-node number to relative index in block group.
53 * @param sb Superblock
54 * @param inode I-node number to be converted
55 * @return Index of the i-node in the block group
57 static uint32_t ext4_ialloc_inode_to_bgidx(struct ext4_sblock *sb,
60 uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
61 return (inode - 1) % inodes_per_group;
64 /**@brief Convert relative index of i-node to absolute i-node number.
65 * @param sb Superblock
66 * @param index Index to be converted
67 * @return Absolute number of the i-node
70 static uint32_t ext4_ialloc_bgidx_to_inode(struct ext4_sblock *sb,
71 uint32_t index, uint32_t bgid)
73 uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
74 return bgid * inodes_per_group + (index + 1);
77 /**@brief Compute block group number from the i-node number.
78 * @param sb Superblock
79 * @param inode I-node number to be found the block group for
80 * @return Block group number computed from i-node number
82 static uint32_t ext4_ialloc_get_bgid_of_inode(struct ext4_sblock *sb,
85 uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
86 return (inode - 1) / inodes_per_group;
89 #if CONFIG_META_CSUM_ENABLE
90 static uint32_t ext4_ialloc_bitmap_csum(struct ext4_sblock *sb, void *bitmap)
93 if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
94 uint32_t inodes_per_group =
95 ext4_get32(sb, inodes_per_group);
97 /* First calculate crc32 checksum against fs uuid */
98 csum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid, sizeof(sb->uuid));
99 /* Then calculate crc32 checksum against inode bitmap */
100 csum = ext4_crc32c(csum, bitmap, (inodes_per_group + 7) / 8);
105 #define ext4_ialloc_bitmap_csum(...) 0
108 void ext4_ialloc_set_bitmap_csum(struct ext4_sblock *sb, struct ext4_bgroup *bg,
109 void *bitmap __unused)
111 int desc_size = ext4_sb_get_desc_size(sb);
112 uint32_t csum = ext4_ialloc_bitmap_csum(sb, bitmap);
113 uint16_t lo_csum = to_le16(csum & 0xFFFF),
114 hi_csum = to_le16(csum >> 16);
116 if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
119 /* See if we need to assign a 32bit checksum */
120 bg->inode_bitmap_csum_lo = lo_csum;
121 if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
122 bg->inode_bitmap_csum_hi = hi_csum;
126 #if CONFIG_META_CSUM_ENABLE
128 ext4_ialloc_verify_bitmap_csum(struct ext4_sblock *sb, struct ext4_bgroup *bg,
129 void *bitmap __unused)
132 int desc_size = ext4_sb_get_desc_size(sb);
133 uint32_t csum = ext4_ialloc_bitmap_csum(sb, bitmap);
134 uint16_t lo_csum = to_le16(csum & 0xFFFF),
135 hi_csum = to_le16(csum >> 16);
137 if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
140 if (bg->inode_bitmap_csum_lo != lo_csum)
143 if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
144 if (bg->inode_bitmap_csum_hi != hi_csum)
150 #define ext4_ialloc_verify_bitmap_csum(...) true
153 int ext4_ialloc_free_inode(struct ext4_fs *fs, uint32_t index, bool is_dir)
155 struct ext4_sblock *sb = &fs->sb;
157 /* Compute index of block group and load it */
158 uint32_t block_group = ext4_ialloc_get_bgid_of_inode(sb, index);
160 struct ext4_block_group_ref bg_ref;
161 int rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
165 struct ext4_bgroup *bg = bg_ref.block_group;
167 /* Load i-node bitmap */
168 uint32_t bitmap_block_addr =
169 ext4_bg_get_inode_bitmap(bg, sb);
172 rc = ext4_block_get(fs->bdev, &b, bitmap_block_addr);
176 if (!ext4_ialloc_verify_bitmap_csum(sb, bg, b.data)) {
177 ext4_dbg(DEBUG_IALLOC,
178 DBG_WARN "Bitmap checksum failed."
179 "Group: %" PRIu32"\n",
183 /* Free i-node in the bitmap */
184 uint32_t index_in_group = ext4_ialloc_inode_to_bgidx(sb, index);
185 ext4_bmap_bit_clr(b.data, index_in_group);
186 ext4_ialloc_set_bitmap_csum(sb, bg, b.data);
189 /* Put back the block with bitmap */
190 rc = ext4_block_set(fs->bdev, &b);
192 /* Error in saving bitmap */
193 ext4_fs_put_block_group_ref(&bg_ref);
197 /* If released i-node is a directory, decrement used directories count
200 uint32_t bg_used_dirs = ext4_bg_get_used_dirs_count(bg, sb);
202 ext4_bg_set_used_dirs_count(bg, sb, bg_used_dirs);
205 /* Update block group free inodes count */
206 uint32_t free_inodes = ext4_bg_get_free_inodes_count(bg, sb);
208 ext4_bg_set_free_inodes_count(bg, sb, free_inodes);
212 /* Put back the modified block group */
213 rc = ext4_fs_put_block_group_ref(&bg_ref);
217 /* Update superblock free inodes count */
218 ext4_set32(sb, free_inodes_count,
219 ext4_get32(sb, free_inodes_count) + 1);
224 int ext4_ialloc_alloc_inode(struct ext4_fs *fs, uint32_t *idx, bool is_dir)
226 struct ext4_sblock *sb = &fs->sb;
228 uint32_t bgid = fs->last_inode_bg_id;
229 uint32_t bg_count = ext4_block_group_cnt(sb);
230 uint32_t sb_free_inodes = ext4_get32(sb, free_inodes_count);
233 /* Try to find free i-node in all block groups */
234 while (bgid <= bg_count) {
236 if (bgid == bg_count) {
239 bg_count = fs->last_inode_bg_id;
245 /* Load block group to check */
246 struct ext4_block_group_ref bg_ref;
247 int rc = ext4_fs_get_block_group_ref(fs, bgid, &bg_ref);
251 struct ext4_bgroup *bg = bg_ref.block_group;
253 /* Read necessary values for algorithm */
254 uint32_t free_inodes = ext4_bg_get_free_inodes_count(bg, sb);
255 uint32_t used_dirs = ext4_bg_get_used_dirs_count(bg, sb);
257 /* Check if this block group is good candidate for allocation */
258 if (free_inodes > 0) {
259 /* Load block with bitmap */
260 uint32_t bmp_blk_add = ext4_bg_get_inode_bitmap(bg, sb);
263 rc = ext4_block_get(fs->bdev, &b, bmp_blk_add);
265 ext4_fs_put_block_group_ref(&bg_ref);
269 if (!ext4_ialloc_verify_bitmap_csum(sb, bg, b.data)) {
270 ext4_dbg(DEBUG_IALLOC,
271 DBG_WARN "Bitmap checksum failed."
272 "Group: %" PRIu32"\n",
276 /* Try to allocate i-node in the bitmap */
277 uint32_t inodes_in_bg;
280 inodes_in_bg = ext4_inodes_in_group_cnt(sb, bgid);
281 rc = ext4_bmap_bit_find_clr(b.data, 0, inodes_in_bg,
283 /* Block group has not any free i-node */
285 rc = ext4_block_set(fs->bdev, &b);
287 ext4_fs_put_block_group_ref(&bg_ref);
291 rc = ext4_fs_put_block_group_ref(&bg_ref);
298 ext4_bmap_bit_set(b.data, idx_in_bg);
300 /* Free i-node found, save the bitmap */
301 ext4_ialloc_set_bitmap_csum(sb,bg,
305 ext4_block_set(fs->bdev, &b);
307 ext4_fs_put_block_group_ref(&bg_ref);
311 /* Modify filesystem counters */
313 ext4_bg_set_free_inodes_count(bg, sb, free_inodes);
315 /* Increment used directories counter */
318 ext4_bg_set_used_dirs_count(bg, sb, used_dirs);
321 /* Decrease unused inodes count */
323 ext4_bg_get_itable_unused(bg, sb);
325 uint32_t free = inodes_in_bg - unused;
327 if (idx_in_bg >= free) {
328 unused = inodes_in_bg - (idx_in_bg + 1);
329 ext4_bg_set_itable_unused(bg, sb, unused);
332 /* Save modified block group */
335 rc = ext4_fs_put_block_group_ref(&bg_ref);
339 /* Update superblock */
341 ext4_set32(sb, free_inodes_count, sb_free_inodes);
343 /* Compute the absolute i-nodex number */
344 *idx = ext4_ialloc_bgidx_to_inode(sb, idx_in_bg, bgid);
346 fs->last_inode_bg_id = bgid;
351 /* Block group not modified, put it and jump to the next block
353 ext4_fs_put_block_group_ref(&bg_ref);