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Commit 69eb33dc authored by Zheng Liu's avatar Zheng Liu Committed by Theodore Ts'o
Browse files

ext4: remove single extent cache 



Single extent cache could be removed because we have extent status tree
as a extent cache, and it would be better.

Signed-off-by: default avatarZheng Liu <wenqing.lz@taobao.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Cc: Jan kara <jack@suse.cz>
parent d100eef2

fs/ext4/ext4.h

+0 −12
Original line number Diff line number Diff line
@@ -809,17 +809,6 @@ do { \ 


#endif /* defined(__KERNEL__) || defined(__linux__) */



/*

 * storage for cached extent

 * If ec_len == 0, then the cache is invalid.

 * If ec_start == 0, then the cache represents a gap (null mapping)

 */

struct ext4_ext_cache {

	ext4_fsblk_t	ec_start;

	ext4_lblk_t	ec_block;

	__u32		ec_len; /* must be 32bit to return holes */

};



#include "extents_status.h"



/*
@@ -886,7 +875,6 @@ struct ext4_inode_info { 
	struct inode vfs_inode;

	struct jbd2_inode *jinode;



	struct ext4_ext_cache i_cached_extent;

	/*

	 * File creation time. Its function is same as that of

	 * struct timespec i_{a,c,m}time in the generic inode.

fs/ext4/ext4_extents.h

+0 −6
Original line number Diff line number Diff line
@@ -193,12 +193,6 @@ static inline unsigned short ext_depth(struct inode *inode) 
	return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);

}



static inline void

ext4_ext_invalidate_cache(struct inode *inode)

{

	EXT4_I(inode)->i_cached_extent.ec_len = 0;

}



static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext)

{

	/* We can not have an uninitialized extent of zero length! */

fs/ext4/extents.c

+38 −141
Original line number Diff line number Diff line
@@ -112,7 +112,7 @@ static int ext4_split_extent_at(handle_t *handle, 
			     int flags);



static int ext4_find_delayed_extent(struct inode *inode,

				    struct ext4_ext_cache *newex);

				    struct extent_status *newes);



static int ext4_ext_truncate_extend_restart(handle_t *handle,

					    struct inode *inode,
@@ -714,7 +714,6 @@ int ext4_ext_tree_init(handle_t *handle, struct inode *inode) 
	eh->eh_magic = EXT4_EXT_MAGIC;

	eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));

	ext4_mark_inode_dirty(handle, inode);

	ext4_ext_invalidate_cache(inode);

	return 0;

}
@@ -1963,7 +1962,6 @@ cleanup: 
		ext4_ext_drop_refs(npath);

		kfree(npath);

	}

	ext4_ext_invalidate_cache(inode);

	return err;

}
@@ -1972,8 +1970,8 @@ static int ext4_fill_fiemap_extents(struct inode *inode, 
				    struct fiemap_extent_info *fieinfo)

{

	struct ext4_ext_path *path = NULL;

	struct ext4_ext_cache newex;

	struct ext4_extent *ex;

	struct extent_status es;

	ext4_lblk_t next, next_del, start = 0, end = 0;

	ext4_lblk_t last = block + num;

	int exists, depth = 0, err = 0;
@@ -2047,31 +2045,31 @@ static int ext4_fill_fiemap_extents(struct inode *inode, 
		BUG_ON(end <= start);



		if (!exists) {

			newex.ec_block = start;

			newex.ec_len = end - start;

			newex.ec_start = 0;

			es.es_lblk = start;

			es.es_len = end - start;

			es.es_pblk = 0;

		} else {

			newex.ec_block = le32_to_cpu(ex->ee_block);

			newex.ec_len = ext4_ext_get_actual_len(ex);

			newex.ec_start = ext4_ext_pblock(ex);

			es.es_lblk = le32_to_cpu(ex->ee_block);

			es.es_len = ext4_ext_get_actual_len(ex);

			es.es_pblk = ext4_ext_pblock(ex);

			if (ext4_ext_is_uninitialized(ex))

				flags |= FIEMAP_EXTENT_UNWRITTEN;

		}



		/*

		 * Find delayed extent and update newex accordingly. We call

		 * it even in !exists case to find out whether newex is the

		 * Find delayed extent and update es accordingly. We call

		 * it even in !exists case to find out whether es is the

		 * last existing extent or not.

		 */

		next_del = ext4_find_delayed_extent(inode, &newex);

		next_del = ext4_find_delayed_extent(inode, &es);

		if (!exists && next_del) {

			exists = 1;

			flags |= FIEMAP_EXTENT_DELALLOC;

		}

		up_read(&EXT4_I(inode)->i_data_sem);



		if (unlikely(newex.ec_len == 0)) {

			EXT4_ERROR_INODE(inode, "newex.ec_len == 0");

		if (unlikely(es.es_len == 0)) {

			EXT4_ERROR_INODE(inode, "es.es_len == 0");

			err = -EIO;

			break;

		}
@@ -2102,9 +2100,9 @@ static int ext4_fill_fiemap_extents(struct inode *inode, 


		if (exists) {

			err = fiemap_fill_next_extent(fieinfo,

				(__u64)newex.ec_block << blksize_bits,

				(__u64)newex.ec_start << blksize_bits,

				(__u64)newex.ec_len << blksize_bits,

				(__u64)es.es_lblk << blksize_bits,

				(__u64)es.es_pblk << blksize_bits,

				(__u64)es.es_len << blksize_bits,

				flags);

			if (err < 0)

				break;
@@ -2114,7 +2112,7 @@ static int ext4_fill_fiemap_extents(struct inode *inode, 
			}

		}



		block = newex.ec_block + newex.ec_len;

		block = es.es_lblk + es.es_len;

	}



	if (path) {
@@ -2125,21 +2123,6 @@ static int ext4_fill_fiemap_extents(struct inode *inode, 
	return err;

}



static void

ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,

			__u32 len, ext4_fsblk_t start)

{

	struct ext4_ext_cache *cex;

	BUG_ON(len == 0);

	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);

	trace_ext4_ext_put_in_cache(inode, block, len, start);

	cex = &EXT4_I(inode)->i_cached_extent;

	cex->ec_block = block;

	cex->ec_len = len;

	cex->ec_start = start;

	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);

}



/*

 * ext4_ext_put_gap_in_cache:

 * calculate boundaries of the gap that the requested block fits into
@@ -2156,9 +2139,10 @@ ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, 


	ex = path[depth].p_ext;

	if (ex == NULL) {

		/* there is no extent yet, so gap is [0;-] */

		lblock = 0;

		len = EXT_MAX_BLOCKS;

		/*

		 * there is no extent yet, so gap is [0;-] and we

		 * don't cache it

		 */

		ext_debug("cache gap(whole file):");

	} else if (block < le32_to_cpu(ex->ee_block)) {

		lblock = block;
@@ -2192,52 +2176,6 @@ ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, 
	}



	ext_debug(" -> %u:%lu\n", lblock, len);

	ext4_ext_put_in_cache(inode, lblock, len, 0);

}



/*

 * ext4_ext_in_cache()

 * Checks to see if the given block is in the cache.

 * If it is, the cached extent is stored in the given

 * cache extent pointer.

 *

 * @inode: The files inode

 * @block: The block to look for in the cache

 * @ex:    Pointer where the cached extent will be stored

 *         if it contains block

 *

 * Return 0 if cache is invalid; 1 if the cache is valid

 */

static int

ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,

		  struct ext4_extent *ex)

{

	struct ext4_ext_cache *cex;

	int ret = 0;



	/*

	 * We borrow i_block_reservation_lock to protect i_cached_extent

	 */

	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);

	cex = &EXT4_I(inode)->i_cached_extent;



	/* has cache valid data? */

	if (cex->ec_len == 0)

		goto errout;



	if (in_range(block, cex->ec_block, cex->ec_len)) {

		ex->ee_block = cpu_to_le32(cex->ec_block);

		ext4_ext_store_pblock(ex, cex->ec_start);

		ex->ee_len = cpu_to_le16(cex->ec_len);

		ext_debug("%u cached by %u:%u:%llu\n",

				block,

				cex->ec_block, cex->ec_len, cex->ec_start);

		ret = 1;

	}

errout:

	trace_ext4_ext_in_cache(inode, block, ret);

	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);

	return ret;

}



/*
@@ -2677,8 +2615,6 @@ static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start, 
		return PTR_ERR(handle);



again:

	ext4_ext_invalidate_cache(inode);



	trace_ext4_ext_remove_space(inode, start, depth);



	/*
@@ -3920,35 +3856,6 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, 
		  map->m_lblk, map->m_len, inode->i_ino);

	trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);



	/* check in cache */

	if (ext4_ext_in_cache(inode, map->m_lblk, &newex)) {

		if (!newex.ee_start_lo && !newex.ee_start_hi) {

			if ((sbi->s_cluster_ratio > 1) &&

			    ext4_find_delalloc_cluster(inode, map->m_lblk))

				map->m_flags |= EXT4_MAP_FROM_CLUSTER;



			if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {

				/*

				 * block isn't allocated yet and

				 * user doesn't want to allocate it

				 */

				goto out2;

			}

			/* we should allocate requested block */

		} else {

			/* block is already allocated */

			if (sbi->s_cluster_ratio > 1)

				map->m_flags |= EXT4_MAP_FROM_CLUSTER;

			newblock = map->m_lblk

				   - le32_to_cpu(newex.ee_block)

				   + ext4_ext_pblock(&newex);

			/* number of remaining blocks in the extent */

			allocated = ext4_ext_get_actual_len(&newex) -

				(map->m_lblk - le32_to_cpu(newex.ee_block));

			goto out;

		}

	}



	/* find extent for this block */

	path = ext4_ext_find_extent(inode, map->m_lblk, NULL);

	if (IS_ERR(path)) {
@@ -3995,15 +3902,9 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, 
			ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,

				  ee_block, ee_len, newblock);



			/*

			 * Do not put uninitialized extent

			 * in the cache

			 */

			if (!ext4_ext_is_uninitialized(ex)) {

				ext4_ext_put_in_cache(inode, ee_block,

					ee_len, ee_start);

			if (!ext4_ext_is_uninitialized(ex))

				goto out;

			}



			allocated = ext4_ext_handle_uninitialized_extents(

				handle, inode, map, path, flags,

				allocated, newblock);
@@ -4265,10 +4166,9 @@ got_allocated_blocks: 
	 * Cache the extent and update transaction to commit on fdatasync only

	 * when it is _not_ an uninitialized extent.

	 */

	if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) {

		ext4_ext_put_in_cache(inode, map->m_lblk, allocated, newblock);

	if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0)

		ext4_update_inode_fsync_trans(handle, inode, 1);

	} else

	else

		ext4_update_inode_fsync_trans(handle, inode, 0);

out:

	if (allocated > map->m_len)
@@ -4327,7 +4227,6 @@ void ext4_ext_truncate(struct inode *inode) 
		goto out_stop;



	down_write(&EXT4_I(inode)->i_data_sem);

	ext4_ext_invalidate_cache(inode);



	ext4_discard_preallocations(inode);
@@ -4576,42 +4475,42 @@ int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset, 
}



/*

 * If newex is not existing extent (newex->ec_start equals zero) find

 * delayed extent at start of newex and update newex accordingly and

 * If newes is not existing extent (newes->ec_pblk equals zero) find

 * delayed extent at start of newes and update newes accordingly and

 * return start of the next delayed extent.

 *

 * If newex is existing extent (newex->ec_start is not equal zero)

 * If newes is existing extent (newes->ec_pblk is not equal zero)

 * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed

 * extent found. Leave newex unmodified.

 * extent found. Leave newes unmodified.

 */

static int ext4_find_delayed_extent(struct inode *inode,

				    struct ext4_ext_cache *newex)

				    struct extent_status *newes)

{

	struct extent_status es;

	ext4_lblk_t block, next_del;



	ext4_es_find_delayed_extent(inode, newex->ec_block, &es);

	ext4_es_find_delayed_extent(inode, newes->es_lblk, &es);



	if (newex->ec_start == 0) {

	if (newes->es_pblk == 0) {

		/*

		 * No extent in extent-tree contains block @newex->ec_start,

		 * No extent in extent-tree contains block @newes->es_pblk,

		 * then the block may stay in 1)a hole or 2)delayed-extent.

		 */

		if (es.es_len == 0)

			/* A hole found. */

			return 0;



		if (es.es_lblk > newex->ec_block) {

		if (es.es_lblk > newes->es_lblk) {

			/* A hole found. */

			newex->ec_len = min(es.es_lblk - newex->ec_block,

					    newex->ec_len);

			newes->es_len = min(es.es_lblk - newes->es_lblk,

					    newes->es_len);

			return 0;

		}



		newex->ec_len = es.es_lblk + es.es_len - newex->ec_block;

		newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;

	}



	block = newex->ec_block + newex->ec_len;

	block = newes->es_lblk + newes->es_len;

	ext4_es_find_delayed_extent(inode, block, &es);

	if (es.es_len == 0)

		next_del = EXT_MAX_BLOCKS;
@@ -4815,14 +4714,12 @@ int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length) 
		goto out;



	down_write(&EXT4_I(inode)->i_data_sem);

	ext4_ext_invalidate_cache(inode);

	ext4_discard_preallocations(inode);



	err = ext4_es_remove_extent(inode, first_block,

				    stop_block - first_block);

	err = ext4_ext_remove_space(inode, first_block, stop_block - 1);



	ext4_ext_invalidate_cache(inode);

	ext4_discard_preallocations(inode);



	if (IS_SYNC(inode))

fs/ext4/move_extent.c

+0 −3
Original line number Diff line number Diff line
@@ -764,9 +764,6 @@ out: 
		kfree(donor_path);

	}



	ext4_ext_invalidate_cache(orig_inode);

	ext4_ext_invalidate_cache(donor_inode);



	return replaced_count;

}

fs/ext4/super.c

+0 −1
Original line number Diff line number Diff line
@@ -836,7 +836,6 @@ static struct inode *ext4_alloc_inode(struct super_block *sb) 
		return NULL;



	ei->vfs_inode.i_version = 1;

	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));

	INIT_LIST_HEAD(&ei->i_prealloc_list);

	spin_lock_init(&ei->i_prealloc_lock);

	ext4_es_init_tree(&ei->i_es_tree);