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1539 lines
45 KiB
1539 lines
45 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
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* linux/fs/ext2/balloc.c |
|
* |
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* Copyright (C) 1992, 1993, 1994, 1995 |
|
* Remy Card ([email protected]) |
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* Laboratoire MASI - Institut Blaise Pascal |
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* Universite Pierre et Marie Curie (Paris VI) |
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* |
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* Enhanced block allocation by Stephen Tweedie ([email protected]), 1993 |
|
* Big-endian to little-endian byte-swapping/bitmaps by |
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* David S. Miller ([email protected]), 1995 |
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*/ |
|
|
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#include "ext2.h" |
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#include <linux/quotaops.h> |
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#include <linux/slab.h> |
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#include <linux/sched.h> |
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#include <linux/cred.h> |
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#include <linux/buffer_head.h> |
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#include <linux/capability.h> |
|
|
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/* |
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* balloc.c contains the blocks allocation and deallocation routines |
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*/ |
|
|
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/* |
|
* The free blocks are managed by bitmaps. A file system contains several |
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* blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap |
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* block for inodes, N blocks for the inode table and data blocks. |
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* |
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* The file system contains group descriptors which are located after the |
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* super block. Each descriptor contains the number of the bitmap block and |
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* the free blocks count in the block. The descriptors are loaded in memory |
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* when a file system is mounted (see ext2_fill_super). |
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*/ |
|
|
|
|
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#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) |
|
|
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struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb, |
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unsigned int block_group, |
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struct buffer_head ** bh) |
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{ |
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unsigned long group_desc; |
|
unsigned long offset; |
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struct ext2_group_desc * desc; |
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struct ext2_sb_info *sbi = EXT2_SB(sb); |
|
|
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if (block_group >= sbi->s_groups_count) { |
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WARN(1, "block_group >= groups_count - " |
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"block_group = %d, groups_count = %lu", |
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block_group, sbi->s_groups_count); |
|
|
|
return NULL; |
|
} |
|
|
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group_desc = block_group >> EXT2_DESC_PER_BLOCK_BITS(sb); |
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offset = block_group & (EXT2_DESC_PER_BLOCK(sb) - 1); |
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if (!sbi->s_group_desc[group_desc]) { |
|
WARN(1, "Group descriptor not loaded - " |
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"block_group = %d, group_desc = %lu, desc = %lu", |
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block_group, group_desc, offset); |
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return NULL; |
|
} |
|
|
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desc = (struct ext2_group_desc *) sbi->s_group_desc[group_desc]->b_data; |
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if (bh) |
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*bh = sbi->s_group_desc[group_desc]; |
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return desc + offset; |
|
} |
|
|
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static int ext2_valid_block_bitmap(struct super_block *sb, |
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struct ext2_group_desc *desc, |
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unsigned int block_group, |
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struct buffer_head *bh) |
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{ |
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ext2_grpblk_t offset; |
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ext2_grpblk_t next_zero_bit; |
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ext2_fsblk_t bitmap_blk; |
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ext2_fsblk_t group_first_block; |
|
|
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group_first_block = ext2_group_first_block_no(sb, block_group); |
|
|
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/* check whether block bitmap block number is set */ |
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bitmap_blk = le32_to_cpu(desc->bg_block_bitmap); |
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offset = bitmap_blk - group_first_block; |
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if (!ext2_test_bit(offset, bh->b_data)) |
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/* bad block bitmap */ |
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goto err_out; |
|
|
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/* check whether the inode bitmap block number is set */ |
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bitmap_blk = le32_to_cpu(desc->bg_inode_bitmap); |
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offset = bitmap_blk - group_first_block; |
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if (!ext2_test_bit(offset, bh->b_data)) |
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/* bad block bitmap */ |
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goto err_out; |
|
|
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/* check whether the inode table block number is set */ |
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bitmap_blk = le32_to_cpu(desc->bg_inode_table); |
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offset = bitmap_blk - group_first_block; |
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next_zero_bit = ext2_find_next_zero_bit(bh->b_data, |
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offset + EXT2_SB(sb)->s_itb_per_group, |
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offset); |
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if (next_zero_bit >= offset + EXT2_SB(sb)->s_itb_per_group) |
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/* good bitmap for inode tables */ |
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return 1; |
|
|
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err_out: |
|
ext2_error(sb, __func__, |
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"Invalid block bitmap - " |
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"block_group = %d, block = %lu", |
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block_group, bitmap_blk); |
|
return 0; |
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} |
|
|
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/* |
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* Read the bitmap for a given block_group,and validate the |
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* bits for block/inode/inode tables are set in the bitmaps |
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* |
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* Return buffer_head on success or NULL in case of failure. |
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*/ |
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static struct buffer_head * |
|
read_block_bitmap(struct super_block *sb, unsigned int block_group) |
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{ |
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struct ext2_group_desc * desc; |
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struct buffer_head * bh = NULL; |
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ext2_fsblk_t bitmap_blk; |
|
|
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desc = ext2_get_group_desc(sb, block_group, NULL); |
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if (!desc) |
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return NULL; |
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bitmap_blk = le32_to_cpu(desc->bg_block_bitmap); |
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bh = sb_getblk(sb, bitmap_blk); |
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if (unlikely(!bh)) { |
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ext2_error(sb, __func__, |
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"Cannot read block bitmap - " |
|
"block_group = %d, block_bitmap = %u", |
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block_group, le32_to_cpu(desc->bg_block_bitmap)); |
|
return NULL; |
|
} |
|
if (likely(bh_uptodate_or_lock(bh))) |
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return bh; |
|
|
|
if (bh_submit_read(bh) < 0) { |
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brelse(bh); |
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ext2_error(sb, __func__, |
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"Cannot read block bitmap - " |
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"block_group = %d, block_bitmap = %u", |
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block_group, le32_to_cpu(desc->bg_block_bitmap)); |
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return NULL; |
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} |
|
|
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ext2_valid_block_bitmap(sb, desc, block_group, bh); |
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/* |
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* file system mounted not to panic on error, continue with corrupt |
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* bitmap |
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*/ |
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return bh; |
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} |
|
|
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static void group_adjust_blocks(struct super_block *sb, int group_no, |
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struct ext2_group_desc *desc, struct buffer_head *bh, int count) |
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{ |
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if (count) { |
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struct ext2_sb_info *sbi = EXT2_SB(sb); |
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unsigned free_blocks; |
|
|
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spin_lock(sb_bgl_lock(sbi, group_no)); |
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free_blocks = le16_to_cpu(desc->bg_free_blocks_count); |
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desc->bg_free_blocks_count = cpu_to_le16(free_blocks + count); |
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spin_unlock(sb_bgl_lock(sbi, group_no)); |
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mark_buffer_dirty(bh); |
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} |
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} |
|
|
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/* |
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* The reservation window structure operations |
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* -------------------------------------------- |
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* Operations include: |
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* dump, find, add, remove, is_empty, find_next_reservable_window, etc. |
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* |
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* We use a red-black tree to represent per-filesystem reservation |
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* windows. |
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* |
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*/ |
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|
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/** |
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* __rsv_window_dump() -- Dump the filesystem block allocation reservation map |
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* @root: root of per-filesystem reservation rb tree |
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* @verbose: verbose mode |
|
* @fn: function which wishes to dump the reservation map |
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* |
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* If verbose is turned on, it will print the whole block reservation |
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* windows(start, end). Otherwise, it will only print out the "bad" windows, |
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* those windows that overlap with their immediate neighbors. |
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*/ |
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#if 1 |
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static void __rsv_window_dump(struct rb_root *root, int verbose, |
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const char *fn) |
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{ |
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struct rb_node *n; |
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struct ext2_reserve_window_node *rsv, *prev; |
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int bad; |
|
|
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restart: |
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n = rb_first(root); |
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bad = 0; |
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prev = NULL; |
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|
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printk("Block Allocation Reservation Windows Map (%s):\n", fn); |
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while (n) { |
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rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node); |
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if (verbose) |
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printk("reservation window 0x%p " |
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"start: %lu, end: %lu\n", |
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rsv, rsv->rsv_start, rsv->rsv_end); |
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if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) { |
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printk("Bad reservation %p (start >= end)\n", |
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rsv); |
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bad = 1; |
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} |
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if (prev && prev->rsv_end >= rsv->rsv_start) { |
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printk("Bad reservation %p (prev->end >= start)\n", |
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rsv); |
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bad = 1; |
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} |
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if (bad) { |
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if (!verbose) { |
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printk("Restarting reservation walk in verbose mode\n"); |
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verbose = 1; |
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goto restart; |
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} |
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} |
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n = rb_next(n); |
|
prev = rsv; |
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} |
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printk("Window map complete.\n"); |
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BUG_ON(bad); |
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} |
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#define rsv_window_dump(root, verbose) \ |
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__rsv_window_dump((root), (verbose), __func__) |
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#else |
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#define rsv_window_dump(root, verbose) do {} while (0) |
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#endif |
|
|
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/** |
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* goal_in_my_reservation() |
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* @rsv: inode's reservation window |
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* @grp_goal: given goal block relative to the allocation block group |
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* @group: the current allocation block group |
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* @sb: filesystem super block |
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* |
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* Test if the given goal block (group relative) is within the file's |
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* own block reservation window range. |
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* |
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* If the reservation window is outside the goal allocation group, return 0; |
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* grp_goal (given goal block) could be -1, which means no specific |
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* goal block. In this case, always return 1. |
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* If the goal block is within the reservation window, return 1; |
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* otherwise, return 0; |
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*/ |
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static int |
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goal_in_my_reservation(struct ext2_reserve_window *rsv, ext2_grpblk_t grp_goal, |
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unsigned int group, struct super_block * sb) |
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{ |
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ext2_fsblk_t group_first_block, group_last_block; |
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|
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group_first_block = ext2_group_first_block_no(sb, group); |
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group_last_block = ext2_group_last_block_no(sb, group); |
|
|
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if ((rsv->_rsv_start > group_last_block) || |
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(rsv->_rsv_end < group_first_block)) |
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return 0; |
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if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start) |
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|| (grp_goal + group_first_block > rsv->_rsv_end))) |
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return 0; |
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return 1; |
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} |
|
|
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/** |
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* search_reserve_window() |
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* @root: root of reservation tree |
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* @goal: target allocation block |
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* |
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* Find the reserved window which includes the goal, or the previous one |
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* if the goal is not in any window. |
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* Returns NULL if there are no windows or if all windows start after the goal. |
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*/ |
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static struct ext2_reserve_window_node * |
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search_reserve_window(struct rb_root *root, ext2_fsblk_t goal) |
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{ |
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struct rb_node *n = root->rb_node; |
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struct ext2_reserve_window_node *rsv; |
|
|
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if (!n) |
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return NULL; |
|
|
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do { |
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rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node); |
|
|
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if (goal < rsv->rsv_start) |
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n = n->rb_left; |
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else if (goal > rsv->rsv_end) |
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n = n->rb_right; |
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else |
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return rsv; |
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} while (n); |
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/* |
|
* We've fallen off the end of the tree: the goal wasn't inside |
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* any particular node. OK, the previous node must be to one |
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* side of the interval containing the goal. If it's the RHS, |
|
* we need to back up one. |
|
*/ |
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if (rsv->rsv_start > goal) { |
|
n = rb_prev(&rsv->rsv_node); |
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rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node); |
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} |
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return rsv; |
|
} |
|
|
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/* |
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* ext2_rsv_window_add() -- Insert a window to the block reservation rb tree. |
|
* @sb: super block |
|
* @rsv: reservation window to add |
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* |
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* Must be called with rsv_lock held. |
|
*/ |
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void ext2_rsv_window_add(struct super_block *sb, |
|
struct ext2_reserve_window_node *rsv) |
|
{ |
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struct rb_root *root = &EXT2_SB(sb)->s_rsv_window_root; |
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struct rb_node *node = &rsv->rsv_node; |
|
ext2_fsblk_t start = rsv->rsv_start; |
|
|
|
struct rb_node ** p = &root->rb_node; |
|
struct rb_node * parent = NULL; |
|
struct ext2_reserve_window_node *this; |
|
|
|
while (*p) |
|
{ |
|
parent = *p; |
|
this = rb_entry(parent, struct ext2_reserve_window_node, rsv_node); |
|
|
|
if (start < this->rsv_start) |
|
p = &(*p)->rb_left; |
|
else if (start > this->rsv_end) |
|
p = &(*p)->rb_right; |
|
else { |
|
rsv_window_dump(root, 1); |
|
BUG(); |
|
} |
|
} |
|
|
|
rb_link_node(node, parent, p); |
|
rb_insert_color(node, root); |
|
} |
|
|
|
/** |
|
* rsv_window_remove() -- unlink a window from the reservation rb tree |
|
* @sb: super block |
|
* @rsv: reservation window to remove |
|
* |
|
* Mark the block reservation window as not allocated, and unlink it |
|
* from the filesystem reservation window rb tree. Must be called with |
|
* rsv_lock held. |
|
*/ |
|
static void rsv_window_remove(struct super_block *sb, |
|
struct ext2_reserve_window_node *rsv) |
|
{ |
|
rsv->rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED; |
|
rsv->rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED; |
|
rsv->rsv_alloc_hit = 0; |
|
rb_erase(&rsv->rsv_node, &EXT2_SB(sb)->s_rsv_window_root); |
|
} |
|
|
|
/* |
|
* rsv_is_empty() -- Check if the reservation window is allocated. |
|
* @rsv: given reservation window to check |
|
* |
|
* returns 1 if the end block is EXT2_RESERVE_WINDOW_NOT_ALLOCATED. |
|
*/ |
|
static inline int rsv_is_empty(struct ext2_reserve_window *rsv) |
|
{ |
|
/* a valid reservation end block could not be 0 */ |
|
return (rsv->_rsv_end == EXT2_RESERVE_WINDOW_NOT_ALLOCATED); |
|
} |
|
|
|
/** |
|
* ext2_init_block_alloc_info() |
|
* @inode: file inode structure |
|
* |
|
* Allocate and initialize the reservation window structure, and |
|
* link the window to the ext2 inode structure at last |
|
* |
|
* The reservation window structure is only dynamically allocated |
|
* and linked to ext2 inode the first time the open file |
|
* needs a new block. So, before every ext2_new_block(s) call, for |
|
* regular files, we should check whether the reservation window |
|
* structure exists or not. In the latter case, this function is called. |
|
* Fail to do so will result in block reservation being turned off for that |
|
* open file. |
|
* |
|
* This function is called from ext2_get_blocks_handle(), also called |
|
* when setting the reservation window size through ioctl before the file |
|
* is open for write (needs block allocation). |
|
* |
|
* Needs truncate_mutex protection prior to calling this function. |
|
*/ |
|
void ext2_init_block_alloc_info(struct inode *inode) |
|
{ |
|
struct ext2_inode_info *ei = EXT2_I(inode); |
|
struct ext2_block_alloc_info *block_i; |
|
struct super_block *sb = inode->i_sb; |
|
|
|
block_i = kmalloc(sizeof(*block_i), GFP_NOFS); |
|
if (block_i) { |
|
struct ext2_reserve_window_node *rsv = &block_i->rsv_window_node; |
|
|
|
rsv->rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED; |
|
rsv->rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED; |
|
|
|
/* |
|
* if filesystem is mounted with NORESERVATION, the goal |
|
* reservation window size is set to zero to indicate |
|
* block reservation is off |
|
*/ |
|
if (!test_opt(sb, RESERVATION)) |
|
rsv->rsv_goal_size = 0; |
|
else |
|
rsv->rsv_goal_size = EXT2_DEFAULT_RESERVE_BLOCKS; |
|
rsv->rsv_alloc_hit = 0; |
|
block_i->last_alloc_logical_block = 0; |
|
block_i->last_alloc_physical_block = 0; |
|
} |
|
ei->i_block_alloc_info = block_i; |
|
} |
|
|
|
/** |
|
* ext2_discard_reservation() |
|
* @inode: inode |
|
* |
|
* Discard(free) block reservation window on last file close, or truncate |
|
* or at last iput(). |
|
* |
|
* It is being called in three cases: |
|
* ext2_release_file(): last writer closes the file |
|
* ext2_clear_inode(): last iput(), when nobody links to this file. |
|
* ext2_truncate(): when the block indirect map is about to change. |
|
*/ |
|
void ext2_discard_reservation(struct inode *inode) |
|
{ |
|
struct ext2_inode_info *ei = EXT2_I(inode); |
|
struct ext2_block_alloc_info *block_i = ei->i_block_alloc_info; |
|
struct ext2_reserve_window_node *rsv; |
|
spinlock_t *rsv_lock = &EXT2_SB(inode->i_sb)->s_rsv_window_lock; |
|
|
|
if (!block_i) |
|
return; |
|
|
|
rsv = &block_i->rsv_window_node; |
|
if (!rsv_is_empty(&rsv->rsv_window)) { |
|
spin_lock(rsv_lock); |
|
if (!rsv_is_empty(&rsv->rsv_window)) |
|
rsv_window_remove(inode->i_sb, rsv); |
|
spin_unlock(rsv_lock); |
|
} |
|
} |
|
|
|
/** |
|
* ext2_free_blocks() -- Free given blocks and update quota and i_blocks |
|
* @inode: inode |
|
* @block: start physical block to free |
|
* @count: number of blocks to free |
|
*/ |
|
void ext2_free_blocks (struct inode * inode, unsigned long block, |
|
unsigned long count) |
|
{ |
|
struct buffer_head *bitmap_bh = NULL; |
|
struct buffer_head * bh2; |
|
unsigned long block_group; |
|
unsigned long bit; |
|
unsigned long i; |
|
unsigned long overflow; |
|
struct super_block * sb = inode->i_sb; |
|
struct ext2_sb_info * sbi = EXT2_SB(sb); |
|
struct ext2_group_desc * desc; |
|
struct ext2_super_block * es = sbi->s_es; |
|
unsigned freed = 0, group_freed; |
|
|
|
if (!ext2_data_block_valid(sbi, block, count)) { |
|
ext2_error (sb, "ext2_free_blocks", |
|
"Freeing blocks not in datazone - " |
|
"block = %lu, count = %lu", block, count); |
|
goto error_return; |
|
} |
|
|
|
ext2_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1); |
|
|
|
do_more: |
|
overflow = 0; |
|
block_group = (block - le32_to_cpu(es->s_first_data_block)) / |
|
EXT2_BLOCKS_PER_GROUP(sb); |
|
bit = (block - le32_to_cpu(es->s_first_data_block)) % |
|
EXT2_BLOCKS_PER_GROUP(sb); |
|
/* |
|
* Check to see if we are freeing blocks across a group |
|
* boundary. |
|
*/ |
|
if (bit + count > EXT2_BLOCKS_PER_GROUP(sb)) { |
|
overflow = bit + count - EXT2_BLOCKS_PER_GROUP(sb); |
|
count -= overflow; |
|
} |
|
brelse(bitmap_bh); |
|
bitmap_bh = read_block_bitmap(sb, block_group); |
|
if (!bitmap_bh) |
|
goto error_return; |
|
|
|
desc = ext2_get_group_desc (sb, block_group, &bh2); |
|
if (!desc) |
|
goto error_return; |
|
|
|
if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) || |
|
in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) || |
|
in_range (block, le32_to_cpu(desc->bg_inode_table), |
|
sbi->s_itb_per_group) || |
|
in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table), |
|
sbi->s_itb_per_group)) { |
|
ext2_error (sb, "ext2_free_blocks", |
|
"Freeing blocks in system zones - " |
|
"Block = %lu, count = %lu", |
|
block, count); |
|
goto error_return; |
|
} |
|
|
|
for (i = 0, group_freed = 0; i < count; i++) { |
|
if (!ext2_clear_bit_atomic(sb_bgl_lock(sbi, block_group), |
|
bit + i, bitmap_bh->b_data)) { |
|
ext2_error(sb, __func__, |
|
"bit already cleared for block %lu", block + i); |
|
} else { |
|
group_freed++; |
|
} |
|
} |
|
|
|
mark_buffer_dirty(bitmap_bh); |
|
if (sb->s_flags & SB_SYNCHRONOUS) |
|
sync_dirty_buffer(bitmap_bh); |
|
|
|
group_adjust_blocks(sb, block_group, desc, bh2, group_freed); |
|
freed += group_freed; |
|
|
|
if (overflow) { |
|
block += count; |
|
count = overflow; |
|
goto do_more; |
|
} |
|
error_return: |
|
brelse(bitmap_bh); |
|
if (freed) { |
|
percpu_counter_add(&sbi->s_freeblocks_counter, freed); |
|
dquot_free_block_nodirty(inode, freed); |
|
mark_inode_dirty(inode); |
|
} |
|
} |
|
|
|
/** |
|
* bitmap_search_next_usable_block() |
|
* @start: the starting block (group relative) of the search |
|
* @bh: bufferhead contains the block group bitmap |
|
* @maxblocks: the ending block (group relative) of the reservation |
|
* |
|
* The bitmap search --- search forward through the actual bitmap on disk until |
|
* we find a bit free. |
|
*/ |
|
static ext2_grpblk_t |
|
bitmap_search_next_usable_block(ext2_grpblk_t start, struct buffer_head *bh, |
|
ext2_grpblk_t maxblocks) |
|
{ |
|
ext2_grpblk_t next; |
|
|
|
next = ext2_find_next_zero_bit(bh->b_data, maxblocks, start); |
|
if (next >= maxblocks) |
|
return -1; |
|
return next; |
|
} |
|
|
|
/** |
|
* find_next_usable_block() |
|
* @start: the starting block (group relative) to find next |
|
* allocatable block in bitmap. |
|
* @bh: bufferhead contains the block group bitmap |
|
* @maxblocks: the ending block (group relative) for the search |
|
* |
|
* Find an allocatable block in a bitmap. We perform the "most |
|
* appropriate allocation" algorithm of looking for a free block near |
|
* the initial goal; then for a free byte somewhere in the bitmap; |
|
* then for any free bit in the bitmap. |
|
*/ |
|
static ext2_grpblk_t |
|
find_next_usable_block(int start, struct buffer_head *bh, int maxblocks) |
|
{ |
|
ext2_grpblk_t here, next; |
|
char *p, *r; |
|
|
|
if (start > 0) { |
|
/* |
|
* The goal was occupied; search forward for a free |
|
* block within the next XX blocks. |
|
* |
|
* end_goal is more or less random, but it has to be |
|
* less than EXT2_BLOCKS_PER_GROUP. Aligning up to the |
|
* next 64-bit boundary is simple.. |
|
*/ |
|
ext2_grpblk_t end_goal = (start + 63) & ~63; |
|
if (end_goal > maxblocks) |
|
end_goal = maxblocks; |
|
here = ext2_find_next_zero_bit(bh->b_data, end_goal, start); |
|
if (here < end_goal) |
|
return here; |
|
ext2_debug("Bit not found near goal\n"); |
|
} |
|
|
|
here = start; |
|
if (here < 0) |
|
here = 0; |
|
|
|
p = ((char *)bh->b_data) + (here >> 3); |
|
r = memscan(p, 0, ((maxblocks + 7) >> 3) - (here >> 3)); |
|
next = (r - ((char *)bh->b_data)) << 3; |
|
|
|
if (next < maxblocks && next >= here) |
|
return next; |
|
|
|
here = bitmap_search_next_usable_block(here, bh, maxblocks); |
|
return here; |
|
} |
|
|
|
/** |
|
* ext2_try_to_allocate() |
|
* @sb: superblock |
|
* @group: given allocation block group |
|
* @bitmap_bh: bufferhead holds the block bitmap |
|
* @grp_goal: given target block within the group |
|
* @count: target number of blocks to allocate |
|
* @my_rsv: reservation window |
|
* |
|
* Attempt to allocate blocks within a give range. Set the range of allocation |
|
* first, then find the first free bit(s) from the bitmap (within the range), |
|
* and at last, allocate the blocks by claiming the found free bit as allocated. |
|
* |
|
* To set the range of this allocation: |
|
* if there is a reservation window, only try to allocate block(s) |
|
* from the file's own reservation window; |
|
* Otherwise, the allocation range starts from the give goal block, |
|
* ends at the block group's last block. |
|
* |
|
* If we failed to allocate the desired block then we may end up crossing to a |
|
* new bitmap. |
|
*/ |
|
static int |
|
ext2_try_to_allocate(struct super_block *sb, int group, |
|
struct buffer_head *bitmap_bh, ext2_grpblk_t grp_goal, |
|
unsigned long *count, |
|
struct ext2_reserve_window *my_rsv) |
|
{ |
|
ext2_fsblk_t group_first_block = ext2_group_first_block_no(sb, group); |
|
ext2_fsblk_t group_last_block = ext2_group_last_block_no(sb, group); |
|
ext2_grpblk_t start, end; |
|
unsigned long num = 0; |
|
|
|
start = 0; |
|
end = group_last_block - group_first_block + 1; |
|
/* we do allocation within the reservation window if we have a window */ |
|
if (my_rsv) { |
|
if (my_rsv->_rsv_start >= group_first_block) |
|
start = my_rsv->_rsv_start - group_first_block; |
|
if (my_rsv->_rsv_end < group_last_block) |
|
end = my_rsv->_rsv_end - group_first_block + 1; |
|
if (grp_goal < start || grp_goal >= end) |
|
grp_goal = -1; |
|
} |
|
BUG_ON(start > EXT2_BLOCKS_PER_GROUP(sb)); |
|
|
|
if (grp_goal < 0) { |
|
grp_goal = find_next_usable_block(start, bitmap_bh, end); |
|
if (grp_goal < 0) |
|
goto fail_access; |
|
if (!my_rsv) { |
|
int i; |
|
|
|
for (i = 0; i < 7 && grp_goal > start && |
|
!ext2_test_bit(grp_goal - 1, |
|
bitmap_bh->b_data); |
|
i++, grp_goal--) |
|
; |
|
} |
|
} |
|
|
|
for (; num < *count && grp_goal < end; grp_goal++) { |
|
if (ext2_set_bit_atomic(sb_bgl_lock(EXT2_SB(sb), group), |
|
grp_goal, bitmap_bh->b_data)) { |
|
if (num == 0) |
|
continue; |
|
break; |
|
} |
|
num++; |
|
} |
|
|
|
if (num == 0) |
|
goto fail_access; |
|
|
|
*count = num; |
|
return grp_goal - num; |
|
fail_access: |
|
return -1; |
|
} |
|
|
|
/** |
|
* find_next_reservable_window(): |
|
* find a reservable space within the given range. |
|
* It does not allocate the reservation window for now: |
|
* alloc_new_reservation() will do the work later. |
|
* |
|
* @search_head: the head of the searching list; |
|
* This is not necessarily the list head of the whole filesystem |
|
* |
|
* We have both head and start_block to assist the search |
|
* for the reservable space. The list starts from head, |
|
* but we will shift to the place where start_block is, |
|
* then start from there, when looking for a reservable space. |
|
* |
|
* @sb: the super block. |
|
* |
|
* @start_block: the first block we consider to start the real search from |
|
* |
|
* @last_block: |
|
* the maximum block number that our goal reservable space |
|
* could start from. This is normally the last block in this |
|
* group. The search will end when we found the start of next |
|
* possible reservable space is out of this boundary. |
|
* This could handle the cross boundary reservation window |
|
* request. |
|
* |
|
* basically we search from the given range, rather than the whole |
|
* reservation double linked list, (start_block, last_block) |
|
* to find a free region that is of my size and has not |
|
* been reserved. |
|
* |
|
*/ |
|
static int find_next_reservable_window( |
|
struct ext2_reserve_window_node *search_head, |
|
struct ext2_reserve_window_node *my_rsv, |
|
struct super_block * sb, |
|
ext2_fsblk_t start_block, |
|
ext2_fsblk_t last_block) |
|
{ |
|
struct rb_node *next; |
|
struct ext2_reserve_window_node *rsv, *prev; |
|
ext2_fsblk_t cur; |
|
int size = my_rsv->rsv_goal_size; |
|
|
|
/* TODO: make the start of the reservation window byte-aligned */ |
|
/* cur = *start_block & ~7;*/ |
|
cur = start_block; |
|
rsv = search_head; |
|
if (!rsv) |
|
return -1; |
|
|
|
while (1) { |
|
if (cur <= rsv->rsv_end) |
|
cur = rsv->rsv_end + 1; |
|
|
|
/* TODO? |
|
* in the case we could not find a reservable space |
|
* that is what is expected, during the re-search, we could |
|
* remember what's the largest reservable space we could have |
|
* and return that one. |
|
* |
|
* For now it will fail if we could not find the reservable |
|
* space with expected-size (or more)... |
|
*/ |
|
if (cur > last_block) |
|
return -1; /* fail */ |
|
|
|
prev = rsv; |
|
next = rb_next(&rsv->rsv_node); |
|
rsv = rb_entry(next,struct ext2_reserve_window_node,rsv_node); |
|
|
|
/* |
|
* Reached the last reservation, we can just append to the |
|
* previous one. |
|
*/ |
|
if (!next) |
|
break; |
|
|
|
if (cur + size <= rsv->rsv_start) { |
|
/* |
|
* Found a reserveable space big enough. We could |
|
* have a reservation across the group boundary here |
|
*/ |
|
break; |
|
} |
|
} |
|
/* |
|
* we come here either : |
|
* when we reach the end of the whole list, |
|
* and there is empty reservable space after last entry in the list. |
|
* append it to the end of the list. |
|
* |
|
* or we found one reservable space in the middle of the list, |
|
* return the reservation window that we could append to. |
|
* succeed. |
|
*/ |
|
|
|
if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window))) |
|
rsv_window_remove(sb, my_rsv); |
|
|
|
/* |
|
* Let's book the whole available window for now. We will check the |
|
* disk bitmap later and then, if there are free blocks then we adjust |
|
* the window size if it's larger than requested. |
|
* Otherwise, we will remove this node from the tree next time |
|
* call find_next_reservable_window. |
|
*/ |
|
my_rsv->rsv_start = cur; |
|
my_rsv->rsv_end = cur + size - 1; |
|
my_rsv->rsv_alloc_hit = 0; |
|
|
|
if (prev != my_rsv) |
|
ext2_rsv_window_add(sb, my_rsv); |
|
|
|
return 0; |
|
} |
|
|
|
/** |
|
* alloc_new_reservation()--allocate a new reservation window |
|
* |
|
* To make a new reservation, we search part of the filesystem |
|
* reservation list (the list that inside the group). We try to |
|
* allocate a new reservation window near the allocation goal, |
|
* or the beginning of the group, if there is no goal. |
|
* |
|
* We first find a reservable space after the goal, then from |
|
* there, we check the bitmap for the first free block after |
|
* it. If there is no free block until the end of group, then the |
|
* whole group is full, we failed. Otherwise, check if the free |
|
* block is inside the expected reservable space, if so, we |
|
* succeed. |
|
* If the first free block is outside the reservable space, then |
|
* start from the first free block, we search for next available |
|
* space, and go on. |
|
* |
|
* on succeed, a new reservation will be found and inserted into the list |
|
* It contains at least one free block, and it does not overlap with other |
|
* reservation windows. |
|
* |
|
* failed: we failed to find a reservation window in this group |
|
* |
|
* @my_rsv: the reservation |
|
* |
|
* @grp_goal: The goal (group-relative). It is where the search for a |
|
* free reservable space should start from. |
|
* if we have a goal(goal >0 ), then start from there, |
|
* no goal(goal = -1), we start from the first block |
|
* of the group. |
|
* |
|
* @sb: the super block |
|
* @group: the group we are trying to allocate in |
|
* @bitmap_bh: the block group block bitmap |
|
* |
|
*/ |
|
static int alloc_new_reservation(struct ext2_reserve_window_node *my_rsv, |
|
ext2_grpblk_t grp_goal, struct super_block *sb, |
|
unsigned int group, struct buffer_head *bitmap_bh) |
|
{ |
|
struct ext2_reserve_window_node *search_head; |
|
ext2_fsblk_t group_first_block, group_end_block, start_block; |
|
ext2_grpblk_t first_free_block; |
|
struct rb_root *fs_rsv_root = &EXT2_SB(sb)->s_rsv_window_root; |
|
unsigned long size; |
|
int ret; |
|
spinlock_t *rsv_lock = &EXT2_SB(sb)->s_rsv_window_lock; |
|
|
|
group_first_block = ext2_group_first_block_no(sb, group); |
|
group_end_block = ext2_group_last_block_no(sb, group); |
|
|
|
if (grp_goal < 0) |
|
start_block = group_first_block; |
|
else |
|
start_block = grp_goal + group_first_block; |
|
|
|
size = my_rsv->rsv_goal_size; |
|
|
|
if (!rsv_is_empty(&my_rsv->rsv_window)) { |
|
/* |
|
* if the old reservation is cross group boundary |
|
* and if the goal is inside the old reservation window, |
|
* we will come here when we just failed to allocate from |
|
* the first part of the window. We still have another part |
|
* that belongs to the next group. In this case, there is no |
|
* point to discard our window and try to allocate a new one |
|
* in this group(which will fail). we should |
|
* keep the reservation window, just simply move on. |
|
* |
|
* Maybe we could shift the start block of the reservation |
|
* window to the first block of next group. |
|
*/ |
|
|
|
if ((my_rsv->rsv_start <= group_end_block) && |
|
(my_rsv->rsv_end > group_end_block) && |
|
(start_block >= my_rsv->rsv_start)) |
|
return -1; |
|
|
|
if ((my_rsv->rsv_alloc_hit > |
|
(my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) { |
|
/* |
|
* if the previously allocation hit ratio is |
|
* greater than 1/2, then we double the size of |
|
* the reservation window the next time, |
|
* otherwise we keep the same size window |
|
*/ |
|
size = size * 2; |
|
if (size > EXT2_MAX_RESERVE_BLOCKS) |
|
size = EXT2_MAX_RESERVE_BLOCKS; |
|
my_rsv->rsv_goal_size= size; |
|
} |
|
} |
|
|
|
spin_lock(rsv_lock); |
|
/* |
|
* shift the search start to the window near the goal block |
|
*/ |
|
search_head = search_reserve_window(fs_rsv_root, start_block); |
|
|
|
/* |
|
* find_next_reservable_window() simply finds a reservable window |
|
* inside the given range(start_block, group_end_block). |
|
* |
|
* To make sure the reservation window has a free bit inside it, we |
|
* need to check the bitmap after we found a reservable window. |
|
*/ |
|
retry: |
|
ret = find_next_reservable_window(search_head, my_rsv, sb, |
|
start_block, group_end_block); |
|
|
|
if (ret == -1) { |
|
if (!rsv_is_empty(&my_rsv->rsv_window)) |
|
rsv_window_remove(sb, my_rsv); |
|
spin_unlock(rsv_lock); |
|
return -1; |
|
} |
|
|
|
/* |
|
* On success, find_next_reservable_window() returns the |
|
* reservation window where there is a reservable space after it. |
|
* Before we reserve this reservable space, we need |
|
* to make sure there is at least a free block inside this region. |
|
* |
|
* Search the first free bit on the block bitmap. Search starts from |
|
* the start block of the reservable space we just found. |
|
*/ |
|
spin_unlock(rsv_lock); |
|
first_free_block = bitmap_search_next_usable_block( |
|
my_rsv->rsv_start - group_first_block, |
|
bitmap_bh, group_end_block - group_first_block + 1); |
|
|
|
if (first_free_block < 0) { |
|
/* |
|
* no free block left on the bitmap, no point |
|
* to reserve the space. return failed. |
|
*/ |
|
spin_lock(rsv_lock); |
|
if (!rsv_is_empty(&my_rsv->rsv_window)) |
|
rsv_window_remove(sb, my_rsv); |
|
spin_unlock(rsv_lock); |
|
return -1; /* failed */ |
|
} |
|
|
|
start_block = first_free_block + group_first_block; |
|
/* |
|
* check if the first free block is within the |
|
* free space we just reserved |
|
*/ |
|
if (start_block >= my_rsv->rsv_start && start_block <= my_rsv->rsv_end) |
|
return 0; /* success */ |
|
/* |
|
* if the first free bit we found is out of the reservable space |
|
* continue search for next reservable space, |
|
* start from where the free block is, |
|
* we also shift the list head to where we stopped last time |
|
*/ |
|
search_head = my_rsv; |
|
spin_lock(rsv_lock); |
|
goto retry; |
|
} |
|
|
|
/** |
|
* try_to_extend_reservation() |
|
* @my_rsv: given reservation window |
|
* @sb: super block |
|
* @size: the delta to extend |
|
* |
|
* Attempt to expand the reservation window large enough to have |
|
* required number of free blocks |
|
* |
|
* Since ext2_try_to_allocate() will always allocate blocks within |
|
* the reservation window range, if the window size is too small, |
|
* multiple blocks allocation has to stop at the end of the reservation |
|
* window. To make this more efficient, given the total number of |
|
* blocks needed and the current size of the window, we try to |
|
* expand the reservation window size if necessary on a best-effort |
|
* basis before ext2_new_blocks() tries to allocate blocks. |
|
*/ |
|
static void try_to_extend_reservation(struct ext2_reserve_window_node *my_rsv, |
|
struct super_block *sb, int size) |
|
{ |
|
struct ext2_reserve_window_node *next_rsv; |
|
struct rb_node *next; |
|
spinlock_t *rsv_lock = &EXT2_SB(sb)->s_rsv_window_lock; |
|
|
|
if (!spin_trylock(rsv_lock)) |
|
return; |
|
|
|
next = rb_next(&my_rsv->rsv_node); |
|
|
|
if (!next) |
|
my_rsv->rsv_end += size; |
|
else { |
|
next_rsv = rb_entry(next, struct ext2_reserve_window_node, rsv_node); |
|
|
|
if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size) |
|
my_rsv->rsv_end += size; |
|
else |
|
my_rsv->rsv_end = next_rsv->rsv_start - 1; |
|
} |
|
spin_unlock(rsv_lock); |
|
} |
|
|
|
/** |
|
* ext2_try_to_allocate_with_rsv() |
|
* @sb: superblock |
|
* @group: given allocation block group |
|
* @bitmap_bh: bufferhead holds the block bitmap |
|
* @grp_goal: given target block within the group |
|
* @count: target number of blocks to allocate |
|
* @my_rsv: reservation window |
|
* |
|
* This is the main function used to allocate a new block and its reservation |
|
* window. |
|
* |
|
* Each time when a new block allocation is need, first try to allocate from |
|
* its own reservation. If it does not have a reservation window, instead of |
|
* looking for a free bit on bitmap first, then look up the reservation list to |
|
* see if it is inside somebody else's reservation window, we try to allocate a |
|
* reservation window for it starting from the goal first. Then do the block |
|
* allocation within the reservation window. |
|
* |
|
* This will avoid keeping on searching the reservation list again and |
|
* again when somebody is looking for a free block (without |
|
* reservation), and there are lots of free blocks, but they are all |
|
* being reserved. |
|
* |
|
* We use a red-black tree for the per-filesystem reservation list. |
|
*/ |
|
static ext2_grpblk_t |
|
ext2_try_to_allocate_with_rsv(struct super_block *sb, unsigned int group, |
|
struct buffer_head *bitmap_bh, ext2_grpblk_t grp_goal, |
|
struct ext2_reserve_window_node * my_rsv, |
|
unsigned long *count) |
|
{ |
|
ext2_fsblk_t group_first_block, group_last_block; |
|
ext2_grpblk_t ret = 0; |
|
unsigned long num = *count; |
|
|
|
/* |
|
* we don't deal with reservation when |
|
* filesystem is mounted without reservation |
|
* or the file is not a regular file |
|
* or last attempt to allocate a block with reservation turned on failed |
|
*/ |
|
if (my_rsv == NULL) { |
|
return ext2_try_to_allocate(sb, group, bitmap_bh, |
|
grp_goal, count, NULL); |
|
} |
|
/* |
|
* grp_goal is a group relative block number (if there is a goal) |
|
* 0 <= grp_goal < EXT2_BLOCKS_PER_GROUP(sb) |
|
* first block is a filesystem wide block number |
|
* first block is the block number of the first block in this group |
|
*/ |
|
group_first_block = ext2_group_first_block_no(sb, group); |
|
group_last_block = ext2_group_last_block_no(sb, group); |
|
|
|
/* |
|
* Basically we will allocate a new block from inode's reservation |
|
* window. |
|
* |
|
* We need to allocate a new reservation window, if: |
|
* a) inode does not have a reservation window; or |
|
* b) last attempt to allocate a block from existing reservation |
|
* failed; or |
|
* c) we come here with a goal and with a reservation window |
|
* |
|
* We do not need to allocate a new reservation window if we come here |
|
* at the beginning with a goal and the goal is inside the window, or |
|
* we don't have a goal but already have a reservation window. |
|
* then we could go to allocate from the reservation window directly. |
|
*/ |
|
while (1) { |
|
if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) || |
|
!goal_in_my_reservation(&my_rsv->rsv_window, |
|
grp_goal, group, sb)) { |
|
if (my_rsv->rsv_goal_size < *count) |
|
my_rsv->rsv_goal_size = *count; |
|
ret = alloc_new_reservation(my_rsv, grp_goal, sb, |
|
group, bitmap_bh); |
|
if (ret < 0) |
|
break; /* failed */ |
|
|
|
if (!goal_in_my_reservation(&my_rsv->rsv_window, |
|
grp_goal, group, sb)) |
|
grp_goal = -1; |
|
} else if (grp_goal >= 0) { |
|
int curr = my_rsv->rsv_end - |
|
(grp_goal + group_first_block) + 1; |
|
|
|
if (curr < *count) |
|
try_to_extend_reservation(my_rsv, sb, |
|
*count - curr); |
|
} |
|
|
|
if ((my_rsv->rsv_start > group_last_block) || |
|
(my_rsv->rsv_end < group_first_block)) { |
|
rsv_window_dump(&EXT2_SB(sb)->s_rsv_window_root, 1); |
|
BUG(); |
|
} |
|
ret = ext2_try_to_allocate(sb, group, bitmap_bh, grp_goal, |
|
&num, &my_rsv->rsv_window); |
|
if (ret >= 0) { |
|
my_rsv->rsv_alloc_hit += num; |
|
*count = num; |
|
break; /* succeed */ |
|
} |
|
num = *count; |
|
} |
|
return ret; |
|
} |
|
|
|
/** |
|
* ext2_has_free_blocks() |
|
* @sbi: in-core super block structure. |
|
* |
|
* Check if filesystem has at least 1 free block available for allocation. |
|
*/ |
|
static int ext2_has_free_blocks(struct ext2_sb_info *sbi) |
|
{ |
|
ext2_fsblk_t free_blocks, root_blocks; |
|
|
|
free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter); |
|
root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count); |
|
if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) && |
|
!uid_eq(sbi->s_resuid, current_fsuid()) && |
|
(gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) || |
|
!in_group_p (sbi->s_resgid))) { |
|
return 0; |
|
} |
|
return 1; |
|
} |
|
|
|
/* |
|
* Returns 1 if the passed-in block region is valid; 0 if some part overlaps |
|
* with filesystem metadata blocks. |
|
*/ |
|
int ext2_data_block_valid(struct ext2_sb_info *sbi, ext2_fsblk_t start_blk, |
|
unsigned int count) |
|
{ |
|
if ((start_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) || |
|
(start_blk + count - 1 < start_blk) || |
|
(start_blk + count - 1 >= le32_to_cpu(sbi->s_es->s_blocks_count))) |
|
return 0; |
|
|
|
/* Ensure we do not step over superblock */ |
|
if ((start_blk <= sbi->s_sb_block) && |
|
(start_blk + count - 1 >= sbi->s_sb_block)) |
|
return 0; |
|
|
|
return 1; |
|
} |
|
|
|
/* |
|
* ext2_new_blocks() -- core block(s) allocation function |
|
* @inode: file inode |
|
* @goal: given target block(filesystem wide) |
|
* @count: target number of blocks to allocate |
|
* @errp: error code |
|
* |
|
* ext2_new_blocks uses a goal block to assist allocation. If the goal is |
|
* free, or there is a free block within 32 blocks of the goal, that block |
|
* is allocated. Otherwise a forward search is made for a free block; within |
|
* each block group the search first looks for an entire free byte in the block |
|
* bitmap, and then for any free bit if that fails. |
|
* This function also updates quota and i_blocks field. |
|
*/ |
|
ext2_fsblk_t ext2_new_blocks(struct inode *inode, ext2_fsblk_t goal, |
|
unsigned long *count, int *errp) |
|
{ |
|
struct buffer_head *bitmap_bh = NULL; |
|
struct buffer_head *gdp_bh; |
|
int group_no; |
|
int goal_group; |
|
ext2_grpblk_t grp_target_blk; /* blockgroup relative goal block */ |
|
ext2_grpblk_t grp_alloc_blk; /* blockgroup-relative allocated block*/ |
|
ext2_fsblk_t ret_block; /* filesyetem-wide allocated block */ |
|
int bgi; /* blockgroup iteration index */ |
|
int performed_allocation = 0; |
|
ext2_grpblk_t free_blocks; /* number of free blocks in a group */ |
|
struct super_block *sb; |
|
struct ext2_group_desc *gdp; |
|
struct ext2_super_block *es; |
|
struct ext2_sb_info *sbi; |
|
struct ext2_reserve_window_node *my_rsv = NULL; |
|
struct ext2_block_alloc_info *block_i; |
|
unsigned short windowsz = 0; |
|
unsigned long ngroups; |
|
unsigned long num = *count; |
|
int ret; |
|
|
|
*errp = -ENOSPC; |
|
sb = inode->i_sb; |
|
|
|
/* |
|
* Check quota for allocation of this block. |
|
*/ |
|
ret = dquot_alloc_block(inode, num); |
|
if (ret) { |
|
*errp = ret; |
|
return 0; |
|
} |
|
|
|
sbi = EXT2_SB(sb); |
|
es = EXT2_SB(sb)->s_es; |
|
ext2_debug("goal=%lu.\n", goal); |
|
/* |
|
* Allocate a block from reservation only when |
|
* filesystem is mounted with reservation(default,-o reservation), and |
|
* it's a regular file, and |
|
* the desired window size is greater than 0 (One could use ioctl |
|
* command EXT2_IOC_SETRSVSZ to set the window size to 0 to turn off |
|
* reservation on that particular file) |
|
*/ |
|
block_i = EXT2_I(inode)->i_block_alloc_info; |
|
if (block_i) { |
|
windowsz = block_i->rsv_window_node.rsv_goal_size; |
|
if (windowsz > 0) |
|
my_rsv = &block_i->rsv_window_node; |
|
} |
|
|
|
if (!ext2_has_free_blocks(sbi)) { |
|
*errp = -ENOSPC; |
|
goto out; |
|
} |
|
|
|
/* |
|
* First, test whether the goal block is free. |
|
*/ |
|
if (goal < le32_to_cpu(es->s_first_data_block) || |
|
goal >= le32_to_cpu(es->s_blocks_count)) |
|
goal = le32_to_cpu(es->s_first_data_block); |
|
group_no = (goal - le32_to_cpu(es->s_first_data_block)) / |
|
EXT2_BLOCKS_PER_GROUP(sb); |
|
goal_group = group_no; |
|
retry_alloc: |
|
gdp = ext2_get_group_desc(sb, group_no, &gdp_bh); |
|
if (!gdp) |
|
goto io_error; |
|
|
|
free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); |
|
/* |
|
* if there is not enough free blocks to make a new resevation |
|
* turn off reservation for this allocation |
|
*/ |
|
if (my_rsv && (free_blocks < windowsz) |
|
&& (free_blocks > 0) |
|
&& (rsv_is_empty(&my_rsv->rsv_window))) |
|
my_rsv = NULL; |
|
|
|
if (free_blocks > 0) { |
|
grp_target_blk = ((goal - le32_to_cpu(es->s_first_data_block)) % |
|
EXT2_BLOCKS_PER_GROUP(sb)); |
|
/* |
|
* In case we retry allocation (due to fs reservation not |
|
* working out or fs corruption), the bitmap_bh is non-null |
|
* pointer and we have to release it before calling |
|
* read_block_bitmap(). |
|
*/ |
|
brelse(bitmap_bh); |
|
bitmap_bh = read_block_bitmap(sb, group_no); |
|
if (!bitmap_bh) |
|
goto io_error; |
|
grp_alloc_blk = ext2_try_to_allocate_with_rsv(sb, group_no, |
|
bitmap_bh, grp_target_blk, |
|
my_rsv, &num); |
|
if (grp_alloc_blk >= 0) |
|
goto allocated; |
|
} |
|
|
|
ngroups = EXT2_SB(sb)->s_groups_count; |
|
smp_rmb(); |
|
|
|
/* |
|
* Now search the rest of the groups. We assume that |
|
* group_no and gdp correctly point to the last group visited. |
|
*/ |
|
for (bgi = 0; bgi < ngroups; bgi++) { |
|
group_no++; |
|
if (group_no >= ngroups) |
|
group_no = 0; |
|
gdp = ext2_get_group_desc(sb, group_no, &gdp_bh); |
|
if (!gdp) |
|
goto io_error; |
|
|
|
free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); |
|
/* |
|
* skip this group (and avoid loading bitmap) if there |
|
* are no free blocks |
|
*/ |
|
if (!free_blocks) |
|
continue; |
|
/* |
|
* skip this group if the number of |
|
* free blocks is less than half of the reservation |
|
* window size. |
|
*/ |
|
if (my_rsv && (free_blocks <= (windowsz/2))) |
|
continue; |
|
|
|
brelse(bitmap_bh); |
|
bitmap_bh = read_block_bitmap(sb, group_no); |
|
if (!bitmap_bh) |
|
goto io_error; |
|
/* |
|
* try to allocate block(s) from this group, without a goal(-1). |
|
*/ |
|
grp_alloc_blk = ext2_try_to_allocate_with_rsv(sb, group_no, |
|
bitmap_bh, -1, my_rsv, &num); |
|
if (grp_alloc_blk >= 0) |
|
goto allocated; |
|
} |
|
/* |
|
* We may end up a bogus earlier ENOSPC error due to |
|
* filesystem is "full" of reservations, but |
|
* there maybe indeed free blocks available on disk |
|
* In this case, we just forget about the reservations |
|
* just do block allocation as without reservations. |
|
*/ |
|
if (my_rsv) { |
|
my_rsv = NULL; |
|
windowsz = 0; |
|
group_no = goal_group; |
|
goto retry_alloc; |
|
} |
|
/* No space left on the device */ |
|
*errp = -ENOSPC; |
|
goto out; |
|
|
|
allocated: |
|
|
|
ext2_debug("using block group %d(%d)\n", |
|
group_no, gdp->bg_free_blocks_count); |
|
|
|
ret_block = grp_alloc_blk + ext2_group_first_block_no(sb, group_no); |
|
|
|
if (in_range(le32_to_cpu(gdp->bg_block_bitmap), ret_block, num) || |
|
in_range(le32_to_cpu(gdp->bg_inode_bitmap), ret_block, num) || |
|
in_range(ret_block, le32_to_cpu(gdp->bg_inode_table), |
|
EXT2_SB(sb)->s_itb_per_group) || |
|
in_range(ret_block + num - 1, le32_to_cpu(gdp->bg_inode_table), |
|
EXT2_SB(sb)->s_itb_per_group)) { |
|
ext2_error(sb, "ext2_new_blocks", |
|
"Allocating block in system zone - " |
|
"blocks from "E2FSBLK", length %lu", |
|
ret_block, num); |
|
/* |
|
* ext2_try_to_allocate marked the blocks we allocated as in |
|
* use. So we may want to selectively mark some of the blocks |
|
* as free |
|
*/ |
|
num = *count; |
|
goto retry_alloc; |
|
} |
|
|
|
performed_allocation = 1; |
|
|
|
if (ret_block + num - 1 >= le32_to_cpu(es->s_blocks_count)) { |
|
ext2_error(sb, "ext2_new_blocks", |
|
"block("E2FSBLK") >= blocks count(%d) - " |
|
"block_group = %d, es == %p ", ret_block, |
|
le32_to_cpu(es->s_blocks_count), group_no, es); |
|
goto out; |
|
} |
|
|
|
group_adjust_blocks(sb, group_no, gdp, gdp_bh, -num); |
|
percpu_counter_sub(&sbi->s_freeblocks_counter, num); |
|
|
|
mark_buffer_dirty(bitmap_bh); |
|
if (sb->s_flags & SB_SYNCHRONOUS) |
|
sync_dirty_buffer(bitmap_bh); |
|
|
|
*errp = 0; |
|
brelse(bitmap_bh); |
|
if (num < *count) { |
|
dquot_free_block_nodirty(inode, *count-num); |
|
mark_inode_dirty(inode); |
|
*count = num; |
|
} |
|
return ret_block; |
|
|
|
io_error: |
|
*errp = -EIO; |
|
out: |
|
/* |
|
* Undo the block allocation |
|
*/ |
|
if (!performed_allocation) { |
|
dquot_free_block_nodirty(inode, *count); |
|
mark_inode_dirty(inode); |
|
} |
|
brelse(bitmap_bh); |
|
return 0; |
|
} |
|
|
|
ext2_fsblk_t ext2_new_block(struct inode *inode, unsigned long goal, int *errp) |
|
{ |
|
unsigned long count = 1; |
|
|
|
return ext2_new_blocks(inode, goal, &count, errp); |
|
} |
|
|
|
#ifdef EXT2FS_DEBUG |
|
|
|
unsigned long ext2_count_free(struct buffer_head *map, unsigned int numchars) |
|
{ |
|
return numchars * BITS_PER_BYTE - memweight(map->b_data, numchars); |
|
} |
|
|
|
#endif /* EXT2FS_DEBUG */ |
|
|
|
unsigned long ext2_count_free_blocks (struct super_block * sb) |
|
{ |
|
struct ext2_group_desc * desc; |
|
unsigned long desc_count = 0; |
|
int i; |
|
#ifdef EXT2FS_DEBUG |
|
unsigned long bitmap_count, x; |
|
struct ext2_super_block *es; |
|
|
|
es = EXT2_SB(sb)->s_es; |
|
desc_count = 0; |
|
bitmap_count = 0; |
|
desc = NULL; |
|
for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) { |
|
struct buffer_head *bitmap_bh; |
|
desc = ext2_get_group_desc (sb, i, NULL); |
|
if (!desc) |
|
continue; |
|
desc_count += le16_to_cpu(desc->bg_free_blocks_count); |
|
bitmap_bh = read_block_bitmap(sb, i); |
|
if (!bitmap_bh) |
|
continue; |
|
|
|
x = ext2_count_free(bitmap_bh, sb->s_blocksize); |
|
printk ("group %d: stored = %d, counted = %lu\n", |
|
i, le16_to_cpu(desc->bg_free_blocks_count), x); |
|
bitmap_count += x; |
|
brelse(bitmap_bh); |
|
} |
|
printk("ext2_count_free_blocks: stored = %lu, computed = %lu, %lu\n", |
|
(long)le32_to_cpu(es->s_free_blocks_count), |
|
desc_count, bitmap_count); |
|
return bitmap_count; |
|
#else |
|
for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) { |
|
desc = ext2_get_group_desc (sb, i, NULL); |
|
if (!desc) |
|
continue; |
|
desc_count += le16_to_cpu(desc->bg_free_blocks_count); |
|
} |
|
return desc_count; |
|
#endif |
|
} |
|
|
|
static inline int test_root(int a, int b) |
|
{ |
|
int num = b; |
|
|
|
while (a > num) |
|
num *= b; |
|
return num == a; |
|
} |
|
|
|
static int ext2_group_sparse(int group) |
|
{ |
|
if (group <= 1) |
|
return 1; |
|
return (test_root(group, 3) || test_root(group, 5) || |
|
test_root(group, 7)); |
|
} |
|
|
|
/** |
|
* ext2_bg_has_super - number of blocks used by the superblock in group |
|
* @sb: superblock for filesystem |
|
* @group: group number to check |
|
* |
|
* Return the number of blocks used by the superblock (primary or backup) |
|
* in this group. Currently this will be only 0 or 1. |
|
*/ |
|
int ext2_bg_has_super(struct super_block *sb, int group) |
|
{ |
|
if (EXT2_HAS_RO_COMPAT_FEATURE(sb,EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)&& |
|
!ext2_group_sparse(group)) |
|
return 0; |
|
return 1; |
|
} |
|
|
|
/** |
|
* ext2_bg_num_gdb - number of blocks used by the group table in group |
|
* @sb: superblock for filesystem |
|
* @group: group number to check |
|
* |
|
* Return the number of blocks used by the group descriptor table |
|
* (primary or backup) in this group. In the future there may be a |
|
* different number of descriptor blocks in each group. |
|
*/ |
|
unsigned long ext2_bg_num_gdb(struct super_block *sb, int group) |
|
{ |
|
return ext2_bg_has_super(sb, group) ? EXT2_SB(sb)->s_gdb_count : 0; |
|
} |
|
|
|
|