diff options
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/bitmap.c | 4 | ||||
| -rw-r--r-- | fs/ext4/ext4.h | 4 | ||||
| -rw-r--r-- | fs/ext4/resize.c | 7 | ||||
| -rw-r--r-- | fs/ext4/super.c | 174 |
4 files changed, 132 insertions, 57 deletions
diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c index 7e86a6d..a94b9c6 100644 --- a/fs/ext4/bitmap.c +++ b/fs/ext4/bitmap.c @@ -11,8 +11,6 @@ #include <linux/jbd2.h> #include "ext4.h" -#ifdef EXT4FS_DEBUG - static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0}; unsigned int ext4_count_free(char *bitmap, unsigned int numchars) @@ -25,8 +23,6 @@ unsigned int ext4_count_free(char *bitmap, unsigned int numchars) return sum; } -#endif /* EXT4FS_DEBUG */ - int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group, struct ext4_group_desc *gdp, struct buffer_head *bh, int sz) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 293fa1c..01434f2 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1161,8 +1161,7 @@ struct ext4_sb_info { unsigned long s_desc_per_block; /* Number of group descriptors per block */ ext4_group_t s_groups_count; /* Number of groups in the fs */ ext4_group_t s_blockfile_groups;/* Groups acceptable for non-extent files */ - unsigned long s_overhead_last; /* Last calculated overhead */ - unsigned long s_blocks_last; /* Last seen block count */ + unsigned long s_overhead; /* # of fs overhead clusters */ unsigned int s_cluster_ratio; /* Number of blocks per cluster */ unsigned int s_cluster_bits; /* log2 of s_cluster_ratio */ loff_t s_bitmap_maxbytes; /* max bytes for bitmap files */ @@ -2037,6 +2036,7 @@ extern int ext4_group_extend(struct super_block *sb, extern int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count); /* super.c */ +extern int ext4_calculate_overhead(struct super_block *sb); extern int ext4_superblock_csum_verify(struct super_block *sb, struct ext4_super_block *es); extern void ext4_superblock_csum_set(struct super_block *sb, diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index 7ea6cbb..17d38de 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1197,7 +1197,7 @@ static void ext4_update_super(struct super_block *sb, struct ext4_new_group_data *group_data = flex_gd->groups; struct ext4_sb_info *sbi = EXT4_SB(sb); struct ext4_super_block *es = sbi->s_es; - int i; + int i, ret; BUG_ON(flex_gd->count == 0 || group_data == NULL); /* @@ -1272,6 +1272,11 @@ static void ext4_update_super(struct super_block *sb, &sbi->s_flex_groups[flex_group].free_inodes); } + /* + * Update the fs overhead information + */ + ext4_calculate_overhead(sb); + if (test_opt(sb, DEBUG)) printk(KERN_DEBUG "EXT4-fs: added group %u:" "%llu blocks(%llu free %llu reserved)\n", flex_gd->count, diff --git a/fs/ext4/super.c b/fs/ext4/super.c index eb7aa3e..78b7ede 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3085,6 +3085,114 @@ static int set_journal_csum_feature_set(struct super_block *sb) return ret; } +/* + * Note: calculating the overhead so we can be compatible with + * historical BSD practice is quite difficult in the face of + * clusters/bigalloc. This is because multiple metadata blocks from + * different block group can end up in the same allocation cluster. + * Calculating the exact overhead in the face of clustered allocation + * requires either O(all block bitmaps) in memory or O(number of block + * groups**2) in time. We will still calculate the superblock for + * older file systems --- and if we come across with a bigalloc file + * system with zero in s_overhead_clusters the estimate will be close to + * correct especially for very large cluster sizes --- but for newer + * file systems, it's better to calculate this figure once at mkfs + * time, and store it in the superblock. If the superblock value is + * present (even for non-bigalloc file systems), we will use it. + */ +static int count_overhead(struct super_block *sb, ext4_group_t grp, + char *buf) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_group_desc *gdp; + ext4_fsblk_t first_block, last_block, b; + ext4_group_t i, ngroups = ext4_get_groups_count(sb); + int s, j, count = 0; + + first_block = le32_to_cpu(sbi->s_es->s_first_data_block) + + (grp * EXT4_BLOCKS_PER_GROUP(sb)); + last_block = first_block + EXT4_BLOCKS_PER_GROUP(sb) - 1; + for (i = 0; i < ngroups; i++) { + gdp = ext4_get_group_desc(sb, i, NULL); + b = ext4_block_bitmap(sb, gdp); + if (b >= first_block && b <= last_block) { + ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf); + count++; + } + b = ext4_inode_bitmap(sb, gdp); + if (b >= first_block && b <= last_block) { + ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf); + count++; + } + b = ext4_inode_table(sb, gdp); + if (b >= first_block && b + sbi->s_itb_per_group <= last_block) + for (j = 0; j < sbi->s_itb_per_group; j++, b++) { + int c = EXT4_B2C(sbi, b - first_block); + ext4_set_bit(c, buf); + count++; + } + if (i != grp) + continue; + s = 0; + if (ext4_bg_has_super(sb, grp)) { + ext4_set_bit(s++, buf); + count++; + } + for (j = ext4_bg_num_gdb(sb, grp); j > 0; j--) { + ext4_set_bit(EXT4_B2C(sbi, s++), buf); + count++; + } + } + if (!count) + return 0; + return EXT4_CLUSTERS_PER_GROUP(sb) - + ext4_count_free(buf, EXT4_CLUSTERS_PER_GROUP(sb) / 8); +} + +/* + * Compute the overhead and stash it in sbi->s_overhead + */ +int ext4_calculate_overhead(struct super_block *sb) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_super_block *es = sbi->s_es; + ext4_group_t i, ngroups = ext4_get_groups_count(sb); + ext4_fsblk_t overhead = 0; + char *buf = (char *) get_zeroed_page(GFP_KERNEL); + + memset(buf, 0, PAGE_SIZE); + if (!buf) + return -ENOMEM; + + /* + * Compute the overhead (FS structures). This is constant + * for a given filesystem unless the number of block groups + * changes so we cache the previous value until it does. + */ + + /* + * All of the blocks before first_data_block are overhead + */ + overhead = EXT4_B2C(sbi, le32_to_cpu(es->s_first_data_block)); + + /* + * Add the overhead found in each block group + */ + for (i = 0; i < ngroups; i++) { + int blks; + + blks = count_overhead(sb, i, buf); + overhead += blks; + if (blks) + memset(buf, 0, PAGE_SIZE); + cond_resched(); + } + sbi->s_overhead = overhead; + smp_wmb(); + free_page((unsigned long) buf); + return 0; +} + static int ext4_fill_super(struct super_block *sb, void *data, int silent) { char *orig_data = kstrdup(data, GFP_KERNEL); @@ -3735,6 +3843,18 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) no_journal: /* + * Get the # of file system overhead blocks from the + * superblock if present. + */ + if (es->s_overhead_clusters) + sbi->s_overhead = le32_to_cpu(es->s_overhead_clusters); + else { + ret = ext4_calculate_overhead(sb); + if (ret) + goto failed_mount_wq; + } + + /* * The maximum number of concurrent works can be high and * concurrency isn't really necessary. Limit it to 1. */ @@ -4600,67 +4720,21 @@ restore_opts: return err; } -/* - * Note: calculating the overhead so we can be compatible with - * historical BSD practice is quite difficult in the face of - * clusters/bigalloc. This is because multiple metadata blocks from - * different block group can end up in the same allocation cluster. - * Calculating the exact overhead in the face of clustered allocation - * requires either O(all block bitmaps) in memory or O(number of block - * groups**2) in time. We will still calculate the superblock for - * older file systems --- and if we come across with a bigalloc file - * system with zero in s_overhead_clusters the estimate will be close to - * correct especially for very large cluster sizes --- but for newer - * file systems, it's better to calculate this figure once at mkfs - * time, and store it in the superblock. If the superblock value is - * present (even for non-bigalloc file systems), we will use it. - */ static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf) { struct super_block *sb = dentry->d_sb; struct ext4_sb_info *sbi = EXT4_SB(sb); struct ext4_super_block *es = sbi->s_es; - struct ext4_group_desc *gdp; + ext4_fsblk_t overhead = 0; u64 fsid; s64 bfree; - if (test_opt(sb, MINIX_DF)) { - sbi->s_overhead_last = 0; - } else if (es->s_overhead_clusters) { - sbi->s_overhead_last = le32_to_cpu(es->s_overhead_clusters); - } else if (sbi->s_blocks_last != ext4_blocks_count(es)) { - ext4_group_t i, ngroups = ext4_get_groups_count(sb); - ext4_fsblk_t overhead = 0; - - /* - * Compute the overhead (FS structures). This is constant - * for a given filesystem unless the number of block groups - * changes so we cache the previous value until it does. - */ - - /* - * All of the blocks before first_data_block are - * overhead - */ - overhead = EXT4_B2C(sbi, le32_to_cpu(es->s_first_data_block)); - - /* - * Add the overhead found in each block group - */ - for (i = 0; i < ngroups; i++) { - gdp = ext4_get_group_desc(sb, i, NULL); - overhead += ext4_num_overhead_clusters(sb, i, gdp); - cond_resched(); - } - sbi->s_overhead_last = overhead; - smp_wmb(); - sbi->s_blocks_last = ext4_blocks_count(es); - } + if (!test_opt(sb, MINIX_DF)) + overhead = sbi->s_overhead; buf->f_type = EXT4_SUPER_MAGIC; buf->f_bsize = sb->s_blocksize; - buf->f_blocks = (ext4_blocks_count(es) - - EXT4_C2B(sbi, sbi->s_overhead_last)); + buf->f_blocks = ext4_blocks_count(es) - EXT4_C2B(sbi, sbi->s_overhead); bfree = percpu_counter_sum_positive(&sbi->s_freeclusters_counter) - percpu_counter_sum_positive(&sbi->s_dirtyclusters_counter); /* prevent underflow in case that few free space is available */ |
