ext4: mballoc avoid use root reserved blocks for non root allocation From: Mingming Cao mballoc allocation missed check for blocks reserved for root users. Add ext4_has_free_blocks() check before allocation. Also modified ext4_has_free_blocks() to support multiple block allocation request. Signed-off-by: Mingming Cao Signed-off-by: "Theodore Ts'o" --- fs/ext4/balloc.c | 51 +++++++++++++++++++++++++++++++++------------------ fs/ext4/ext4.h | 2 ++ fs/ext4/mballoc.c | 7 ++++++- 3 files changed, 41 insertions(+), 19 deletions(-) Index: linux-2.6.26-rc9/fs/ext4/balloc.c =================================================================== --- linux-2.6.26-rc9.orig/fs/ext4/balloc.c 2008-07-11 16:05:05.000000000 -0700 +++ linux-2.6.26-rc9/fs/ext4/balloc.c 2008-07-11 16:05:06.000000000 -0700 @@ -1599,23 +1599,35 @@ out: /** * ext4_has_free_blocks() - * @sbi: in-core super block structure. + * @sbi: in-core super block structure. + * @nblocks: number of neeed blocks * - * Check if filesystem has at least 1 free block available for allocation. + * Check if filesystem has free blocks available for allocation. + * Return the number of blocks avaible for allocation for this request + * On success, return nblocks */ -static int ext4_has_free_blocks(struct ext4_sb_info *sbi) +ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi, + ext4_fsblk_t nblocks) { - ext4_fsblk_t free_blocks, root_blocks; + ext4_fsblk_t free_blocks; + ext4_fsblk_t root_blocks = 0; free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter); - root_blocks = ext4_r_blocks_count(sbi->s_es); - if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) && + + if (!capable(CAP_SYS_RESOURCE) && sbi->s_resuid != current->fsuid && - (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) { - return 0; - } - return 1; -} + (sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid))) + root_blocks = ext4_r_blocks_count(sbi->s_es); +#ifdef CONFIG_SMP + if (free_blocks - root_blocks < FBC_BATCH) + free_blocks = + percpu_counter_sum_positive(&sbi->s_freeblocks_counter); +#endif + if (free_blocks - root_blocks < nblocks) + return free_blocks - root_blocks; + return nblocks; + } + /** * ext4_should_retry_alloc() @@ -1631,7 +1643,7 @@ static int ext4_has_free_blocks(struct e */ int ext4_should_retry_alloc(struct super_block *sb, int *retries) { - if (!ext4_has_free_blocks(EXT4_SB(sb)) || (*retries)++ > 3) + if (!ext4_has_free_blocks(EXT4_SB(sb), 1) || (*retries)++ > 3) return 0; jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); @@ -1681,13 +1693,21 @@ ext4_fsblk_t ext4_old_new_blocks(handle_ ext4_group_t ngroups; unsigned long num = *count; - *errp = -ENOSPC; sb = inode->i_sb; if (!sb) { + *errp = -ENODEV; printk("ext4_new_block: nonexistent device"); return 0; } + sbi = EXT4_SB(sb); + *count = ext4_has_free_blocks(sbi, *count); + if (*count == 0) { + *errp = -ENOSPC; + return 0; /*return with ENOSPC error */ + } + num = *count; + /* * Check quota for allocation of this block. */ @@ -1711,11 +1731,6 @@ ext4_fsblk_t ext4_old_new_blocks(handle_ if (block_i && ((windowsz = block_i->rsv_window_node.rsv_goal_size) > 0)) my_rsv = &block_i->rsv_window_node; - if (!ext4_has_free_blocks(sbi)) { - *errp = -ENOSPC; - goto out; - } - /* * First, test whether the goal block is free. */ Index: linux-2.6.26-rc9/fs/ext4/ext4.h =================================================================== --- linux-2.6.26-rc9.orig/fs/ext4/ext4.h 2008-07-11 16:05:05.000000000 -0700 +++ linux-2.6.26-rc9/fs/ext4/ext4.h 2008-07-11 16:05:06.000000000 -0700 @@ -979,6 +979,8 @@ extern ext4_fsblk_t ext4_new_blocks(hand unsigned long *count, int *errp); extern ext4_fsblk_t ext4_old_new_blocks(handle_t *handle, struct inode *inode, ext4_fsblk_t goal, unsigned long *count, int *errp); +extern ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi, + ext4_fsblk_t nblocks); extern void ext4_free_blocks (handle_t *handle, struct inode *inode, ext4_fsblk_t block, unsigned long count, int metadata); extern void ext4_free_blocks_sb (handle_t *handle, struct super_block *sb, Index: linux-2.6.26-rc9/fs/ext4/mballoc.c =================================================================== --- linux-2.6.26-rc9.orig/fs/ext4/mballoc.c 2008-07-11 16:05:05.000000000 -0700 +++ linux-2.6.26-rc9/fs/ext4/mballoc.c 2008-07-11 16:05:06.000000000 -0700 @@ -4043,6 +4043,12 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t &(ar->len), errp); return block; } + ar->len = ext4_has_free_blocks(sbi, ar->len); + + if (ar->len == 0) { + *errp = -ENOSPC; + return 0; + } while (ar->len && DQUOT_ALLOC_BLOCK(ar->inode, ar->len)) { ar->flags |= EXT4_MB_HINT_NOPREALLOC; @@ -4071,7 +4077,6 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t ac->ac_op = EXT4_MB_HISTORY_PREALLOC; if (!ext4_mb_use_preallocated(ac)) { - ac->ac_op = EXT4_MB_HISTORY_ALLOC; ext4_mb_normalize_request(ac, ar); repeat: