ref: b465297573ef0ae41d3a2cdbcb5528f3388ba6d9
dir: /lwext4/ext4_ialloc.c/
/* * Copyright (c) 2013 Grzegorz Kostka ([email protected]) * * * HelenOS: * Copyright (c) 2012 Martin Sucha * Copyright (c) 2012 Frantisek Princ * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * - The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /** @addtogroup lwext4 * @{ */ /** * @file ext4_ialloc.c * @brief Inode allocation procedures. */ #include "ext4_config.h" #include "ext4_types.h" #include "ext4_ialloc.h" #include "ext4_super.h" #include "ext4_crc32c.h" #include "ext4_fs.h" #include "ext4_blockdev.h" #include "ext4_block_group.h" #include "ext4_bitmap.h" /**@brief Convert i-node number to relative index in block group. * @param sb Superblock * @param inode I-node number to be converted * @return Index of the i-node in the block group */ static uint32_t ext4_ialloc_inode_to_bgidx(struct ext4_sblock *sb, uint32_t inode) { uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group); return (inode - 1) % inodes_per_group; } /**@brief Convert relative index of i-node to absolute i-node number. * @param sb Superblock * @param index Index to be converted * @return Absolute number of the i-node * */ static uint32_t ext4_ialloc_bgidx_to_inode(struct ext4_sblock *sb, uint32_t index, uint32_t bgid) { uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group); return bgid * inodes_per_group + (index + 1); } /**@brief Compute block group number from the i-node number. * @param sb Superblock * @param inode I-node number to be found the block group for * @return Block group number computed from i-node number */ static uint32_t ext4_ialloc_get_bgid_of_inode(struct ext4_sblock *sb, uint32_t inode) { uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group); return (inode - 1) / inodes_per_group; } #if CONFIG_META_CSUM_ENABLE static uint32_t ext4_ialloc_bitmap_csum(struct ext4_sblock *sb, void *bitmap) { uint32_t csum = 0; if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) { uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group); /* First calculate crc32 checksum against fs uuid */ csum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid, sizeof(sb->uuid)); /* Then calculate crc32 checksum against inode bitmap */ csum = ext4_crc32c(csum, bitmap, (inodes_per_group + 7) / 8); } return csum; } #else #define ext4_ialloc_bitmap_csum(...) 0 #endif void ext4_ialloc_set_bitmap_csum(struct ext4_sblock *sb, struct ext4_bgroup *bg, void *bitmap __unused) { int desc_size = ext4_sb_get_desc_size(sb); uint32_t csum = ext4_ialloc_bitmap_csum(sb, bitmap); uint16_t lo_csum = to_le16(csum & 0xFFFF), hi_csum = to_le16(csum >> 16); if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) return; /* See if we need to assign a 32bit checksum */ bg->inode_bitmap_csum_lo = lo_csum; if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE) bg->inode_bitmap_csum_hi = hi_csum; } #if CONFIG_META_CSUM_ENABLE static bool ext4_ialloc_verify_bitmap_csum(struct ext4_sblock *sb, struct ext4_bgroup *bg, void *bitmap __unused) { int desc_size = ext4_sb_get_desc_size(sb); uint32_t csum = ext4_ialloc_bitmap_csum(sb, bitmap); uint16_t lo_csum = to_le16(csum & 0xFFFF), hi_csum = to_le16(csum >> 16); if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) return true; if (bg->inode_bitmap_csum_lo != lo_csum) return false; if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE) if (bg->inode_bitmap_csum_hi != hi_csum) return false; return true; } #else #define ext4_ialloc_verify_bitmap_csum(...) true #endif int ext4_ialloc_free_inode(struct ext4_fs *fs, uint32_t index, bool is_dir) { struct ext4_sblock *sb = &fs->sb; /* Compute index of block group and load it */ uint32_t block_group = ext4_ialloc_get_bgid_of_inode(sb, index); struct ext4_block_group_ref bg_ref; int rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref); if (rc != EOK) return rc; struct ext4_bgroup *bg = bg_ref.block_group; /* Load i-node bitmap */ uint32_t bitmap_block_addr = ext4_bg_get_inode_bitmap(bg, sb); struct ext4_block b; rc = ext4_block_get(fs->bdev, &b, bitmap_block_addr); if (rc != EOK) return rc; if (!ext4_ialloc_verify_bitmap_csum(sb, bg, b.data)) { ext4_dbg(DEBUG_IALLOC, DBG_WARN "Bitmap checksum failed." "Group: %" PRIu32"\n", bg_ref.index); } /* Free i-node in the bitmap */ uint32_t index_in_group = ext4_ialloc_inode_to_bgidx(sb, index); ext4_bmap_bit_clr(b.data, index_in_group); ext4_ialloc_set_bitmap_csum(sb, bg, b.data); ext4_bcache_set_dirty(b.buf); /* Put back the block with bitmap */ rc = ext4_block_set(fs->bdev, &b); if (rc != EOK) { /* Error in saving bitmap */ ext4_fs_put_block_group_ref(&bg_ref); return rc; } /* If released i-node is a directory, decrement used directories count */ if (is_dir) { uint32_t bg_used_dirs = ext4_bg_get_used_dirs_count(bg, sb); bg_used_dirs--; ext4_bg_set_used_dirs_count(bg, sb, bg_used_dirs); } /* Update block group free inodes count */ uint32_t free_inodes = ext4_bg_get_free_inodes_count(bg, sb); free_inodes++; ext4_bg_set_free_inodes_count(bg, sb, free_inodes); bg_ref.dirty = true; /* Put back the modified block group */ rc = ext4_fs_put_block_group_ref(&bg_ref); if (rc != EOK) return rc; /* Update superblock free inodes count */ ext4_set32(sb, free_inodes_count, ext4_get32(sb, free_inodes_count) + 1); return EOK; } int ext4_ialloc_alloc_inode(struct ext4_fs *fs, uint32_t *idx, bool is_dir) { struct ext4_sblock *sb = &fs->sb; uint32_t bgid = fs->last_inode_bg_id; uint32_t bg_count = ext4_block_group_cnt(sb); uint32_t sb_free_inodes = ext4_get32(sb, free_inodes_count); bool rewind = false; /* Try to find free i-node in all block groups */ while (bgid <= bg_count) { if (bgid == bg_count) { if (rewind) break; bg_count = fs->last_inode_bg_id; bgid = 0; rewind = true; continue; } /* Load block group to check */ struct ext4_block_group_ref bg_ref; int rc = ext4_fs_get_block_group_ref(fs, bgid, &bg_ref); if (rc != EOK) return rc; struct ext4_bgroup *bg = bg_ref.block_group; /* Read necessary values for algorithm */ uint32_t free_inodes = ext4_bg_get_free_inodes_count(bg, sb); uint32_t used_dirs = ext4_bg_get_used_dirs_count(bg, sb); /* Check if this block group is good candidate for allocation */ if (free_inodes > 0) { /* Load block with bitmap */ uint32_t bmp_blk_add = ext4_bg_get_inode_bitmap(bg, sb); struct ext4_block b; rc = ext4_block_get(fs->bdev, &b, bmp_blk_add); if (rc != EOK) { ext4_fs_put_block_group_ref(&bg_ref); return rc; } if (!ext4_ialloc_verify_bitmap_csum(sb, bg, b.data)) { ext4_dbg(DEBUG_IALLOC, DBG_WARN "Bitmap checksum failed." "Group: %" PRIu32"\n", bg_ref.index); } /* Try to allocate i-node in the bitmap */ uint32_t inodes_in_bg; uint32_t idx_in_bg; inodes_in_bg = ext4_inodes_in_group_cnt(sb, bgid); rc = ext4_bmap_bit_find_clr(b.data, 0, inodes_in_bg, &idx_in_bg); /* Block group has not any free i-node */ if (rc == ENOSPC) { rc = ext4_block_set(fs->bdev, &b); if (rc != EOK) { ext4_fs_put_block_group_ref(&bg_ref); return rc; } rc = ext4_fs_put_block_group_ref(&bg_ref); if (rc != EOK) return rc; continue; } ext4_bmap_bit_set(b.data, idx_in_bg); /* Free i-node found, save the bitmap */ ext4_ialloc_set_bitmap_csum(sb,bg, b.data); ext4_bcache_set_dirty(b.buf); ext4_block_set(fs->bdev, &b); if (rc != EOK) { ext4_fs_put_block_group_ref(&bg_ref); return rc; } /* Modify filesystem counters */ free_inodes--; ext4_bg_set_free_inodes_count(bg, sb, free_inodes); /* Increment used directories counter */ if (is_dir) { used_dirs++; ext4_bg_set_used_dirs_count(bg, sb, used_dirs); } /* Decrease unused inodes count */ uint32_t unused = ext4_bg_get_itable_unused(bg, sb); uint32_t free = inodes_in_bg - unused; if (idx_in_bg >= free) { unused = inodes_in_bg - (idx_in_bg + 1); ext4_bg_set_itable_unused(bg, sb, unused); } /* Save modified block group */ bg_ref.dirty = true; rc = ext4_fs_put_block_group_ref(&bg_ref); if (rc != EOK) return rc; /* Update superblock */ sb_free_inodes--; ext4_set32(sb, free_inodes_count, sb_free_inodes); /* Compute the absolute i-nodex number */ *idx = ext4_ialloc_bgidx_to_inode(sb, idx_in_bg, bgid); fs->last_inode_bg_id = bgid; return EOK; } /* Block group not modified, put it and jump to the next block * group */ ext4_fs_put_block_group_ref(&bg_ref); if (rc != EOK) return rc; ++bgid; } return ENOSPC; } /** * @} */