---

yaml
---
r: 139483
b: refs/heads/master
c: a491212
h: refs/heads/master
i:
  139481: 0538e0e
  139479: c29dbd5
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2dc6b0d48ca0599837df21b14bb8393d0804af57
+refs/heads/master: a4912123b688e057084e6557cef8924f7ae5bbde

trunk/fs/ext4/ext4.h

@@ -827,6 +827,12 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
 #define EXT4_DEF_MIN_BATCH_TIME	0
 #define EXT4_DEF_MAX_BATCH_TIME	15000 /* 15ms */
 
+/*
+ * Minimum number of groups in a flexgroup before we separate out
+ * directories into the first block group of a flexgroup
+ */
+#define EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME	4
+
 /*
  * Structure of a directory entry
  */

trunk/fs/ext4/ext4_i.h

@@ -122,6 +122,9 @@ struct ext4_inode_info {
 	struct list_head i_prealloc_list;
 	spinlock_t i_prealloc_lock;
 
+	/* ialloc */
+	ext4_group_t	i_last_alloc_group;
+
 	/* allocation reservation info for delalloc */
 	unsigned int i_reserved_data_blocks;
 	unsigned int i_reserved_meta_blocks;

trunk/fs/ext4/extents.c

@@ -152,6 +152,8 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 	ext4_fsblk_t bg_start;
 	ext4_fsblk_t last_block;
 	ext4_grpblk_t colour;
+	ext4_group_t block_group;
+	int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
 	int depth;
 
 	if (path) {
@@ -170,10 +172,31 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 	}
 
 	/* OK. use inode's group */
-	bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) +
+	block_group = ei->i_block_group;
+	if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
+		/*
+		 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
+		 * block groups per flexgroup, reserve the first block 
+		 * group for directories and special files.  Regular 
+		 * files will start at the second block group.  This
+		 * tends to speed up directory access and improves 
+		 * fsck times.
+		 */
+		block_group &= ~(flex_size-1);
+		if (S_ISREG(inode->i_mode))
+			block_group++;
+	}
+	bg_start = (block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) +
 		le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block);
 	last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
 
+	/*
+	 * If we are doing delayed allocation, we don't need take
+	 * colour into account.
+	 */
+	if (test_opt(inode->i_sb, DELALLOC))
+		return bg_start;
+
 	if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
 		colour = (current->pid % 16) *
 			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);

trunk/fs/ext4/ialloc.c

@@ -410,6 +410,43 @@ static int find_group_flex(struct super_block *sb, struct inode *parent,
 	return 0;
 }
 
+struct orlov_stats {
+	__u32 free_inodes;
+	__u32 free_blocks;
+	__u32 used_dirs;
+};
+
+/*
+ * Helper function for Orlov's allocator; returns critical information
+ * for a particular block group or flex_bg.  If flex_size is 1, then g
+ * is a block group number; otherwise it is flex_bg number.
+ */
+void get_orlov_stats(struct super_block *sb, ext4_group_t g,
+		       int flex_size, struct orlov_stats *stats)
+{
+	struct ext4_group_desc *desc;
+	ext4_group_t		ngroups = EXT4_SB(sb)->s_groups_count;
+	int			i;
+
+	stats->free_inodes = 0;
+	stats->free_blocks = 0;
+	stats->used_dirs = 0;
+
+	g *= flex_size;
+
+	for (i = 0; i < flex_size; i++) {
+		if (g >= ngroups)
+			break;
+		desc = ext4_get_group_desc(sb, g++, NULL);
+		if (!desc)
+			continue;
+
+		stats->free_inodes += ext4_free_inodes_count(sb, desc);
+		stats->free_blocks += ext4_free_blks_count(sb, desc);
+		stats->used_dirs += ext4_used_dirs_count(sb, desc);
+	}
+}
+
 /*
  * Orlov's allocator for directories.
  *
@@ -425,35 +462,34 @@ static int find_group_flex(struct super_block *sb, struct inode *parent,
  * it has too many directories already (max_dirs) or
  * it has too few free inodes left (min_inodes) or
  * it has too few free blocks left (min_blocks) or
- * it's already running too large debt (max_debt).
  * Parent's group is preferred, if it doesn't satisfy these
  * conditions we search cyclically through the rest. If none
  * of the groups look good we just look for a group with more
  * free inodes than average (starting at parent's group).
- *
- * Debt is incremented each time we allocate a directory and decremented
- * when we allocate an inode, within 0--255.
  */
 
-#define INODE_COST 64
-#define BLOCK_COST 256
-
 static int find_group_orlov(struct super_block *sb, struct inode *parent,
-				ext4_group_t *group)
+			    ext4_group_t *group, int mode)
 {
 	ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
-	struct ext4_super_block *es = sbi->s_es;
 	ext4_group_t ngroups = sbi->s_groups_count;
 	int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 	unsigned int freei, avefreei;
 	ext4_fsblk_t freeb, avefreeb;
-	ext4_fsblk_t blocks_per_dir;
 	unsigned int ndirs;
-	int max_debt, max_dirs, min_inodes;
+	int max_dirs, min_inodes;
 	ext4_grpblk_t min_blocks;
-	ext4_group_t i;
+	ext4_group_t i, grp, g;
 	struct ext4_group_desc *desc;
+	struct orlov_stats stats;
+	int flex_size = ext4_flex_bg_size(sbi);
+
+	if (flex_size > 1) {
+		ngroups = (ngroups + flex_size - 1) >>
+			sbi->s_log_groups_per_flex;
+		parent_group >>= sbi->s_log_groups_per_flex;
+	}
 
 	freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 	avefreei = freei / ngroups;
@@ -462,71 +498,97 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
 	do_div(avefreeb, ngroups);
 	ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 
-	if ((parent == sb->s_root->d_inode) ||
-	    (EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL)) {
+	if (S_ISDIR(mode) &&
+	    ((parent == sb->s_root->d_inode) ||
+	     (EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL))) {
 		int best_ndir = inodes_per_group;
-		ext4_group_t grp;
 		int ret = -1;
 
 		get_random_bytes(&grp, sizeof(grp));
 		parent_group = (unsigned)grp % ngroups;
 		for (i = 0; i < ngroups; i++) {
-			grp = (parent_group + i) % ngroups;
-			desc = ext4_get_group_desc(sb, grp, NULL);
-			if (!desc || !ext4_free_inodes_count(sb, desc))
+			g = (parent_group + i) % ngroups;
+			get_orlov_stats(sb, g, flex_size, &stats);
+			if (!stats.free_inodes)
 				continue;
-			if (ext4_used_dirs_count(sb, desc) >= best_ndir)
+			if (stats.used_dirs >= best_ndir)
 				continue;
-			if (ext4_free_inodes_count(sb, desc) < avefreei)
+			if (stats.free_inodes < avefreei)
 				continue;
-			if (ext4_free_blks_count(sb, desc) < avefreeb)
+			if (stats.free_blocks < avefreeb)
 				continue;
-			*group = grp;
+			grp = g;
 			ret = 0;
-			best_ndir = ext4_used_dirs_count(sb, desc);
+			best_ndir = stats.used_dirs;
+		}
+		if (ret)
+			goto fallback;
+	found_flex_bg:
+		if (flex_size == 1) {
+			*group = grp;
+			return 0;
+		}
+
+		/*
+		 * We pack inodes at the beginning of the flexgroup's
+		 * inode tables.  Block allocation decisions will do
+		 * something similar, although regular files will
+		 * start at 2nd block group of the flexgroup.  See
+		 * ext4_ext_find_goal() and ext4_find_near().
+		 */
+		grp *= flex_size;
+		for (i = 0; i < flex_size; i++) {
+			if (grp+i >= sbi->s_groups_count)
+				break;
+			desc = ext4_get_group_desc(sb, grp+i, NULL);
+			if (desc && ext4_free_inodes_count(sb, desc)) {
+				*group = grp+i;
+				return 0;
+			}
 		}
-		if (ret == 0)
-			return ret;
 		goto fallback;
 	}
 
-	blocks_per_dir = ext4_blocks_count(es) - freeb;
-	do_div(blocks_per_dir, ndirs);
-
 	max_dirs = ndirs / ngroups + inodes_per_group / 16;
-	min_inodes = avefreei - inodes_per_group / 4;
-	min_blocks = avefreeb - EXT4_BLOCKS_PER_GROUP(sb) / 4;
-
-	max_debt = EXT4_BLOCKS_PER_GROUP(sb);
-	max_debt /= max_t(int, blocks_per_dir, BLOCK_COST);
-	if (max_debt * INODE_COST > inodes_per_group)
-		max_debt = inodes_per_group / INODE_COST;
-	if (max_debt > 255)
-		max_debt = 255;
-	if (max_debt == 0)
-		max_debt = 1;
+	min_inodes = avefreei - inodes_per_group*flex_size / 4;
+	if (min_inodes < 1)
+		min_inodes = 1;
+	min_blocks = avefreeb - EXT4_BLOCKS_PER_GROUP(sb)*flex_size / 4;
+
+	/*
+	 * Start looking in the flex group where we last allocated an
+	 * inode for this parent directory
+	 */
+	if (EXT4_I(parent)->i_last_alloc_group != ~0) {
+		parent_group = EXT4_I(parent)->i_last_alloc_group;
+		if (flex_size > 1)
+			parent_group >>= sbi->s_log_groups_per_flex;
+	}
 
 	for (i = 0; i < ngroups; i++) {
-		*group = (parent_group + i) % ngroups;
-		desc = ext4_get_group_desc(sb, *group, NULL);
-		if (!desc || !ext4_free_inodes_count(sb, desc))
-			continue;
-		if (ext4_used_dirs_count(sb, desc) >= max_dirs)
+		grp = (parent_group + i) % ngroups;
+		get_orlov_stats(sb, grp, flex_size, &stats);
+		if (stats.used_dirs >= max_dirs)
 			continue;
-		if (ext4_free_inodes_count(sb, desc) < min_inodes)
+		if (stats.free_inodes < min_inodes)
 			continue;
-		if (ext4_free_blks_count(sb, desc) < min_blocks)
+		if (stats.free_blocks < min_blocks)
 			continue;
-		return 0;
+		goto found_flex_bg;
 	}
 
 fallback:
+	ngroups = sbi->s_groups_count;
+	avefreei = freei / ngroups;
+	parent_group = EXT4_I(parent)->i_block_group;
 	for (i = 0; i < ngroups; i++) {
-		*group = (parent_group + i) % ngroups;
-		desc = ext4_get_group_desc(sb, *group, NULL);
+		grp = (parent_group + i) % ngroups;
+		desc = ext4_get_group_desc(sb, grp, NULL);
 		if (desc && ext4_free_inodes_count(sb, desc) &&
-			ext4_free_inodes_count(sb, desc) >= avefreei)
+		    ext4_free_inodes_count(sb, desc) >= avefreei) {
+			*group = grp;
 			return 0;
+		}
 	}
 
 	if (avefreei) {
@@ -542,12 +604,51 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
 }
 
 static int find_group_other(struct super_block *sb, struct inode *parent,
-				ext4_group_t *group)
+			    ext4_group_t *group, int mode)
 {
 	ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
 	struct ext4_group_desc *desc;
-	ext4_group_t i;
+	ext4_group_t i, last;
+	int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
+
+	/*
+	 * Try to place the inode is the same flex group as its
+	 * parent.  If we can't find space, use the Orlov algorithm to
+	 * find another flex group, and store that information in the
+	 * parent directory's inode information so that use that flex
+	 * group for future allocations.
+	 */
+	if (flex_size > 1) {
+		int retry = 0;
+
+	try_again:
+		parent_group &= ~(flex_size-1);
+		last = parent_group + flex_size;
+		if (last > ngroups)
+			last = ngroups;
+		for  (i = parent_group; i < last; i++) {
+			desc = ext4_get_group_desc(sb, i, NULL);
+			if (desc && ext4_free_inodes_count(sb, desc)) {
+				*group = i;
+				return 0;
+			}
+		}
+		if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
+			retry = 1;
+			parent_group = EXT4_I(parent)->i_last_alloc_group;
+			goto try_again;
+		}
+		/*
+		 * If this didn't work, use the Orlov search algorithm
+		 * to find a new flex group; we pass in the mode to
+		 * avoid the topdir algorithms.
+		 */
+		*group = parent_group + flex_size;
+		if (*group > ngroups)
+			*group = 0;
+		return find_group_orlov(sb, parent, group, mode);
+	}
 
 	/*
 	 * Try to place the inode in its parent directory
@@ -716,10 +817,10 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode)
 	sbi = EXT4_SB(sb);
 	es = sbi->s_es;
 
-	if (sbi->s_log_groups_per_flex) {
+	if (sbi->s_log_groups_per_flex && test_opt(sb, OLDALLOC)) {
 		ret2 = find_group_flex(sb, dir, &group);
 		if (ret2 == -1) {
-			ret2 = find_group_other(sb, dir, &group);
+			ret2 = find_group_other(sb, dir, &group, mode);
 			if (ret2 == 0 && once)
 				once = 0;
 				printk(KERN_NOTICE "ext4: find_group_flex "
@@ -733,11 +834,12 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode)
 		if (test_opt(sb, OLDALLOC))
 			ret2 = find_group_dir(sb, dir, &group);
 		else
-			ret2 = find_group_orlov(sb, dir, &group);
+			ret2 = find_group_orlov(sb, dir, &group, mode);
 	} else
-		ret2 = find_group_other(sb, dir, &group);
+		ret2 = find_group_other(sb, dir, &group, mode);
 
 got_group:
+	EXT4_I(dir)->i_last_alloc_group = group;
 	err = -ENOSPC;
 	if (ret2 == -1)
 		goto out;
@@ -894,6 +996,7 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode)
 	ei->i_file_acl = 0;
 	ei->i_dtime = 0;
 	ei->i_block_group = group;
+	ei->i_last_alloc_group = ~0;
 
 	ext4_set_inode_flags(inode);
 	if (IS_DIRSYNC(inode))