aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorBadari Pulavarty <pbadari@us.ibm.com>2007-07-15 23:42:00 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-16 09:05:52 -0700
commit5e70030d4cf91613530a23b40ad9919bb9ee114f (patch)
tree30a53102b73179840cac06ed325ece645585a566
parenta71ce8c6c9bf269b192f352ea555217815cf027e (diff)
downloadmrst-s0i3-test-5e70030d4cf91613530a23b40ad9919bb9ee114f.tar.gz
mrst-s0i3-test-5e70030d4cf91613530a23b40ad9919bb9ee114f.tar.xz
mrst-s0i3-test-5e70030d4cf91613530a23b40ad9919bb9ee114f.zip
ext4: statfs speed up
This is a patch that speeds up statfs. It is very simple - the "overhead" calculation, which takes a huge amount of time for large filesystems, never changes unless the size of the filesystem itself changes. That means we can store it in memory and only recalculate if the filesystem has been resized (almost never). It also fixes a minor problem that we never update the on-disk superblock free blocks/inodes counts until the filesystem is unmounted. While not fatal, we may as well update that on disk when we have the information, and it makes things like debugfs and dumpe2fs report a bit more accurate info. Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Andreas Dilger <adilger@clusterfs.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/ext4/super.c25
-rw-r--r--include/linux/ext4_fs_sb.h2
2 files changed, 17 insertions, 10 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index adcbfadfcb4..d0d8c76c7ed 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2500,19 +2500,19 @@ 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;
- ext4_fsblk_t overhead;
- int i;
u64 fsid;
- if (test_opt (sb, MINIX_DF))
- overhead = 0;
- else {
- unsigned long ngroups;
- ngroups = EXT4_SB(sb)->s_groups_count;
+ if (test_opt(sb, MINIX_DF)) {
+ sbi->s_overhead_last = 0;
+ } else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
+ unsigned long ngroups = sbi->s_groups_count, i;
+ ext4_fsblk_t overhead = 0;
smp_rmb();
/*
- * Compute the overhead (FS structures)
+ * 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.
*/
/*
@@ -2536,18 +2536,23 @@ static int ext4_statfs (struct dentry * dentry, struct kstatfs * buf)
* Every block group has an inode bitmap, a block
* bitmap, and an inode table.
*/
- overhead += (ngroups * (2 + EXT4_SB(sb)->s_itb_per_group));
+ overhead += ngroups * (2 + sbi->s_itb_per_group);
+ sbi->s_overhead_last = overhead;
+ smp_wmb();
+ sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
}
buf->f_type = EXT4_SUPER_MAGIC;
buf->f_bsize = sb->s_blocksize;
- buf->f_blocks = ext4_blocks_count(es) - overhead;
+ buf->f_blocks = ext4_blocks_count(es) - sbi->s_overhead_last;
buf->f_bfree = percpu_counter_sum(&sbi->s_freeblocks_counter);
+ es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
buf->f_bavail = buf->f_bfree - ext4_r_blocks_count(es);
if (buf->f_bfree < ext4_r_blocks_count(es))
buf->f_bavail = 0;
buf->f_files = le32_to_cpu(es->s_inodes_count);
buf->f_ffree = percpu_counter_sum(&sbi->s_freeinodes_counter);
+ es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
buf->f_namelen = EXT4_NAME_LEN;
fsid = le64_to_cpup((void *)es->s_uuid) ^
le64_to_cpup((void *)es->s_uuid + sizeof(u64));
diff --git a/include/linux/ext4_fs_sb.h b/include/linux/ext4_fs_sb.h
index 691a713139c..2347557a327 100644
--- a/include/linux/ext4_fs_sb.h
+++ b/include/linux/ext4_fs_sb.h
@@ -39,6 +39,8 @@ struct ext4_sb_info {
unsigned long s_gdb_count; /* Number of group descriptor blocks */
unsigned long s_desc_per_block; /* Number of group descriptors per block */
unsigned long s_groups_count; /* Number of groups in the fs */
+ unsigned long s_overhead_last; /* Last calculated overhead */
+ unsigned long s_blocks_last; /* Last seen block count */
struct buffer_head * s_sbh; /* Buffer containing the super block */
struct ext4_super_block * s_es; /* Pointer to the super block in the buffer */
struct buffer_head ** s_group_desc;