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

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 11d13c6ee9f62c00f35eaa5f7d2c113097c76fdb..7cd484d4b29ee8bd4da94891be1c9d6510d884e5 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -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.

diff --git a/fs/ext4/ext4_extents.h b/fs/ext4/ext4_extents.h
index 487fda12bc00223f8533ce0699d96e8fd207df4e..8643ff5bbeb7a9954af0026ce43601d02487856b 100644 (file)
--- a/fs/ext4/ext4_extents.h
+++ b/fs/ext4/ext4_extents.h
@@ -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! */

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 3d369c4ca3fec12d3c42b63727e75bf849ededac..61015f0ff1f5c6ea9061feea8ae59d82ed787275 100644 (file)
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -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))

diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 0d6734394eacd61ba7063bb6ee216432c831816e..d78c33eed7e54a1d75dff016bbf1ddc49e7c1e0b 100644 (file)
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -764,9 +764,6 @@ out:
                kfree(donor_path);
        }
 
-       ext4_ext_invalidate_cache(orig_inode);
-       ext4_ext_invalidate_cache(donor_inode);
-
        return replaced_count;
 }
 

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index ef6ac59e4961c65ac3823c983e91ac000038a331..d80bfe5ac11c726ee300ec98c31f41a4248b8ac1 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -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);