ext4: cache all of an extent tree's leaf block upon reading
When we read in an extent tree leaf block from disk, arrange to have
all of its entries cached. In nearly all cases the in-memory
representation will be more compact than the on-disk representation in
the buffer cache, and it allows us to get the information without
having to traverse the extent tree for successive extents.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 0ab26fb..c74b194 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -561,6 +561,17 @@
#define EXT4_GET_BLOCKS_NO_PUT_HOLE 0x0200
/*
+ * The bit position of this flag must not overlap with any of the
+ * EXT4_GET_BLOCKS_*. It is used by ext4_ext_find_extent(),
+ * read_extent_tree_block(), ext4_split_extent_at(),
+ * ext4_ext_insert_extent(), and ext4_ext_create_new_leaf() to
+ * indicate that the we shouldn't be caching the extents when reading
+ * from the extent tree while a truncate or punch hole operation
+ * is in progress.
+ */
+#define EXT4_EX_NOCACHE 0x0400
+
+/*
* Flags used by ext4_free_blocks
*/
#define EXT4_FREE_BLOCKS_METADATA 0x0001
@@ -2684,7 +2695,8 @@
struct ext4_ext_path *,
struct ext4_extent *, int);
extern struct ext4_ext_path *ext4_ext_find_extent(struct inode *, ext4_lblk_t,
- struct ext4_ext_path *);
+ struct ext4_ext_path *,
+ int flags);
extern void ext4_ext_drop_refs(struct ext4_ext_path *);
extern int ext4_ext_check_inode(struct inode *inode);
extern int ext4_find_delalloc_range(struct inode *inode,
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 6e7b7d9..08c1ac9 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -466,7 +466,8 @@
static struct buffer_head *
__read_extent_tree_block(const char *function, unsigned int line,
- struct inode *inode, ext4_fsblk_t pblk, int depth)
+ struct inode *inode, ext4_fsblk_t pblk, int depth,
+ int flags)
{
struct buffer_head *bh;
int err;
@@ -488,6 +489,32 @@
if (err)
goto errout;
set_buffer_verified(bh);
+ /*
+ * If this is a leaf block, cache all of its entries
+ */
+ if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
+ struct ext4_extent_header *eh = ext_block_hdr(bh);
+ struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
+ ext4_lblk_t prev = 0;
+ int i;
+
+ for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
+ unsigned int status = EXTENT_STATUS_WRITTEN;
+ ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
+ int len = ext4_ext_get_actual_len(ex);
+
+ if (prev && (prev != lblk))
+ ext4_es_cache_extent(inode, prev,
+ lblk - prev, ~0,
+ EXTENT_STATUS_HOLE);
+
+ if (ext4_ext_is_uninitialized(ex))
+ status = EXTENT_STATUS_UNWRITTEN;
+ ext4_es_cache_extent(inode, lblk, len,
+ ext4_ext_pblock(ex), status);
+ prev = lblk + len;
+ }
+ }
return bh;
errout:
put_bh(bh);
@@ -495,8 +522,9 @@
}
-#define read_extent_tree_block(inode, pblk, depth) \
- __read_extent_tree_block(__func__, __LINE__, (inode), (pblk), (depth))
+#define read_extent_tree_block(inode, pblk, depth, flags) \
+ __read_extent_tree_block(__func__, __LINE__, (inode), (pblk), \
+ (depth), (flags))
#ifdef EXT_DEBUG
static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
@@ -730,7 +758,7 @@
struct ext4_ext_path *
ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
- struct ext4_ext_path *path)
+ struct ext4_ext_path *path, int flags)
{
struct ext4_extent_header *eh;
struct buffer_head *bh;
@@ -762,7 +790,8 @@
path[ppos].p_depth = i;
path[ppos].p_ext = NULL;
- bh = read_extent_tree_block(inode, path[ppos].p_block, --i);
+ bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
+ flags);
if (IS_ERR(bh)) {
ret = PTR_ERR(bh);
goto err;
@@ -1199,7 +1228,8 @@
* if no free index is found, then it requests in-depth growing.
*/
static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
- unsigned int flags,
+ unsigned int mb_flags,
+ unsigned int gb_flags,
struct ext4_ext_path *path,
struct ext4_extent *newext)
{
@@ -1221,7 +1251,7 @@
if (EXT_HAS_FREE_INDEX(curp)) {
/* if we found index with free entry, then use that
* entry: create all needed subtree and add new leaf */
- err = ext4_ext_split(handle, inode, flags, path, newext, i);
+ err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
if (err)
goto out;
@@ -1229,12 +1259,12 @@
ext4_ext_drop_refs(path);
path = ext4_ext_find_extent(inode,
(ext4_lblk_t)le32_to_cpu(newext->ee_block),
- path);
+ path, gb_flags);
if (IS_ERR(path))
err = PTR_ERR(path);
} else {
/* tree is full, time to grow in depth */
- err = ext4_ext_grow_indepth(handle, inode, flags, newext);
+ err = ext4_ext_grow_indepth(handle, inode, mb_flags, newext);
if (err)
goto out;
@@ -1242,7 +1272,7 @@
ext4_ext_drop_refs(path);
path = ext4_ext_find_extent(inode,
(ext4_lblk_t)le32_to_cpu(newext->ee_block),
- path);
+ path, gb_flags);
if (IS_ERR(path)) {
err = PTR_ERR(path);
goto out;
@@ -1415,7 +1445,7 @@
while (++depth < path->p_depth) {
/* subtract from p_depth to get proper eh_depth */
bh = read_extent_tree_block(inode, block,
- path->p_depth - depth);
+ path->p_depth - depth, 0);
if (IS_ERR(bh))
return PTR_ERR(bh);
eh = ext_block_hdr(bh);
@@ -1424,7 +1454,7 @@
put_bh(bh);
}
- bh = read_extent_tree_block(inode, block, path->p_depth - depth);
+ bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
if (IS_ERR(bh))
return PTR_ERR(bh);
eh = ext_block_hdr(bh);
@@ -1786,7 +1816,7 @@
*/
int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path,
- struct ext4_extent *newext, int flag)
+ struct ext4_extent *newext, int gb_flags)
{
struct ext4_extent_header *eh;
struct ext4_extent *ex, *fex;
@@ -1795,7 +1825,7 @@
int depth, len, err;
ext4_lblk_t next;
unsigned uninitialized = 0;
- int flags = 0;
+ int mb_flags = 0;
if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
@@ -1810,7 +1840,7 @@
}
/* try to insert block into found extent and return */
- if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO)) {
+ if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
/*
* Try to see whether we should rather test the extent on
@@ -1913,7 +1943,7 @@
if (next != EXT_MAX_BLOCKS) {
ext_debug("next leaf block - %u\n", next);
BUG_ON(npath != NULL);
- npath = ext4_ext_find_extent(inode, next, NULL);
+ npath = ext4_ext_find_extent(inode, next, NULL, 0);
if (IS_ERR(npath))
return PTR_ERR(npath);
BUG_ON(npath->p_depth != path->p_depth);
@@ -1932,9 +1962,10 @@
* There is no free space in the found leaf.
* We're gonna add a new leaf in the tree.
*/
- if (flag & EXT4_GET_BLOCKS_METADATA_NOFAIL)
- flags = EXT4_MB_USE_RESERVED;
- err = ext4_ext_create_new_leaf(handle, inode, flags, path, newext);
+ if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
+ mb_flags = EXT4_MB_USE_RESERVED;
+ err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
+ path, newext);
if (err)
goto cleanup;
depth = ext_depth(inode);
@@ -2000,7 +2031,7 @@
merge:
/* try to merge extents */
- if (!(flag & EXT4_GET_BLOCKS_PRE_IO))
+ if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
ext4_ext_try_to_merge(handle, inode, path, nearex);
@@ -2043,7 +2074,7 @@
path = NULL;
}
- path = ext4_ext_find_extent(inode, block, path);
+ path = ext4_ext_find_extent(inode, block, path, 0);
if (IS_ERR(path)) {
up_read(&EXT4_I(inode)->i_data_sem);
err = PTR_ERR(path);
@@ -2705,7 +2736,7 @@
ext4_lblk_t ee_block;
/* find extent for this block */
- path = ext4_ext_find_extent(inode, end, NULL);
+ path = ext4_ext_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
if (IS_ERR(path)) {
ext4_journal_stop(handle);
return PTR_ERR(path);
@@ -2747,6 +2778,7 @@
*/
err = ext4_split_extent_at(handle, inode, path,
end + 1, split_flag,
+ EXT4_EX_NOCACHE |
EXT4_GET_BLOCKS_PRE_IO |
EXT4_GET_BLOCKS_METADATA_NOFAIL);
@@ -2823,7 +2855,8 @@
i + 1, ext4_idx_pblock(path[i].p_idx));
memset(path + i + 1, 0, sizeof(*path));
bh = read_extent_tree_block(inode,
- ext4_idx_pblock(path[i].p_idx), depth - i - 1);
+ ext4_idx_pblock(path[i].p_idx), depth - i - 1,
+ EXT4_EX_NOCACHE);
if (IS_ERR(bh)) {
/* should we reset i_size? */
err = PTR_ERR(bh);
@@ -3170,7 +3203,7 @@
* result in split of original leaf or extent zeroout.
*/
ext4_ext_drop_refs(path);
- path = ext4_ext_find_extent(inode, map->m_lblk, path);
+ path = ext4_ext_find_extent(inode, map->m_lblk, path, 0);
if (IS_ERR(path))
return PTR_ERR(path);
depth = ext_depth(inode);
@@ -3554,7 +3587,7 @@
if (err < 0)
goto out;
ext4_ext_drop_refs(path);
- path = ext4_ext_find_extent(inode, map->m_lblk, path);
+ path = ext4_ext_find_extent(inode, map->m_lblk, path, 0);
if (IS_ERR(path)) {
err = PTR_ERR(path);
goto out;
@@ -4041,7 +4074,7 @@
trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
/* find extent for this block */
- path = ext4_ext_find_extent(inode, map->m_lblk, NULL);
+ path = ext4_ext_find_extent(inode, map->m_lblk, NULL, 0);
if (IS_ERR(path)) {
err = PTR_ERR(path);
path = NULL;
@@ -4760,6 +4793,6 @@
error = ext4_fill_fiemap_extents(inode, start_blk,
len_blks, fieinfo);
}
-
+ ext4_es_lru_add(inode);
return error;
}
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index ded2615..1dc5df0 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -419,7 +419,7 @@
unsigned short ee_len;
int depth, ee_status, es_status;
- path = ext4_ext_find_extent(inode, es->es_lblk, NULL);
+ path = ext4_ext_find_extent(inode, es->es_lblk, NULL, EXT4_EX_NOCACHE);
if (IS_ERR(path))
return;
@@ -684,6 +684,41 @@
}
/*
+ * ext4_es_cache_extent() inserts information into the extent status
+ * tree if and only if there isn't information about the range in
+ * question already.
+ */
+void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk,
+ ext4_lblk_t len, ext4_fsblk_t pblk,
+ unsigned int status)
+{
+ struct extent_status *es;
+ struct extent_status newes;
+ ext4_lblk_t end = lblk + len - 1;
+
+ newes.es_lblk = lblk;
+ newes.es_len = len;
+ ext4_es_store_pblock(&newes, pblk);
+ ext4_es_store_status(&newes, status);
+ trace_ext4_es_cache_extent(inode, &newes);
+
+ if (!len)
+ return;
+
+ BUG_ON(end < lblk);
+
+ write_lock(&EXT4_I(inode)->i_es_lock);
+
+ es = __es_tree_search(&EXT4_I(inode)->i_es_tree.root, lblk);
+ if (es && ((es->es_lblk <= lblk) || (es->es_lblk <= end)))
+ goto out;
+
+ __es_insert_extent(inode, &newes);
+out:
+ write_unlock(&EXT4_I(inode)->i_es_lock);
+}
+
+/*
* ext4_es_lookup_extent() looks up an extent in extent status tree.
*
* ext4_es_lookup_extent is called by ext4_map_blocks/ext4_da_map_blocks.
diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h
index d72af84..3e83aef 100644
--- a/fs/ext4/extents_status.h
+++ b/fs/ext4/extents_status.h
@@ -71,6 +71,9 @@
extern int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
ext4_lblk_t len, ext4_fsblk_t pblk,
unsigned int status);
+extern void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk,
+ ext4_lblk_t len, ext4_fsblk_t pblk,
+ unsigned int status);
extern int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
ext4_lblk_t len);
extern void ext4_es_find_delayed_extent_range(struct inode *inode,
diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
index 49e8bdf..f99bdb8 100644
--- a/fs/ext4/migrate.c
+++ b/fs/ext4/migrate.c
@@ -39,7 +39,7 @@
newext.ee_block = cpu_to_le32(lb->first_block);
newext.ee_len = cpu_to_le16(lb->last_block - lb->first_block + 1);
ext4_ext_store_pblock(&newext, lb->first_pblock);
- path = ext4_ext_find_extent(inode, lb->first_block, NULL);
+ path = ext4_ext_find_extent(inode, lb->first_block, NULL, 0);
if (IS_ERR(path)) {
retval = PTR_ERR(path);
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index e86dddbd..7fa4d85 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -37,7 +37,7 @@
int ret = 0;
struct ext4_ext_path *path;
- path = ext4_ext_find_extent(inode, lblock, *orig_path);
+ path = ext4_ext_find_extent(inode, lblock, *orig_path, EXT4_EX_NOCACHE);
if (IS_ERR(path))
ret = PTR_ERR(path);
else if (path[ext_depth(inode)].p_ext == NULL)