ext4: use pre-allocated es in __es_insert_extent()

Pass a extent_status pointer prealloc to __es_insert_extent(). If the
pointer is non-null, it is used directly when a new extent_status is
needed to avoid memory allocation failures.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230424033846.4732-5-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index 703e9a8..2ac1f6e 100644 (file)
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -144,7 +144,8 @@
 static struct kmem_cache *ext4_es_cachep;
 static struct kmem_cache *ext4_pending_cachep;
 
-static int __es_insert_extent(struct inode *inode, struct extent_status *newes);
+static int __es_insert_extent(struct inode *inode, struct extent_status *newes,
+                             struct extent_status *prealloc);
 static int __es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
                              ext4_lblk_t end, int *reserved);
 static int es_reclaim_extents(struct ext4_inode_info *ei, int *nr_to_scan);
@@ -766,7 +767,8 @@ static inline void ext4_es_insert_extent_check(struct inode *inode,
 }
 #endif
 
-static int __es_insert_extent(struct inode *inode, struct extent_status *newes)
+static int __es_insert_extent(struct inode *inode, struct extent_status *newes,
+                             struct extent_status *prealloc)
 {
        struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
        struct rb_node **p = &tree->root.rb_node;
@@ -806,7 +808,10 @@ static int __es_insert_extent(struct inode *inode, struct extent_status *newes)
                }
        }
 
-       es = __es_alloc_extent(false);
+       if (prealloc)
+               es = prealloc;
+       else
+               es = __es_alloc_extent(false);
        if (!es)
                return -ENOMEM;
        ext4_es_init_extent(inode, es, newes->es_lblk, newes->es_len,
@@ -866,7 +871,7 @@ int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
        if (err != 0)
                goto error;
 retry:
-       err = __es_insert_extent(inode, &newes);
+       err = __es_insert_extent(inode, &newes, NULL);
        if (err == -ENOMEM && __es_shrink(EXT4_SB(inode->i_sb),
                                          128, EXT4_I(inode)))
                goto retry;
@@ -916,7 +921,7 @@ void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk,
 
        es = __es_tree_search(&EXT4_I(inode)->i_es_tree.root, lblk);
        if (!es || es->es_lblk > end)
-               __es_insert_extent(inode, &newes);
+               __es_insert_extent(inode, &newes, NULL);
        write_unlock(&EXT4_I(inode)->i_es_lock);
 }
 
@@ -1362,7 +1367,7 @@ retry:
                                        orig_es.es_len - len2;
                        ext4_es_store_pblock_status(&newes, block,
                                                    ext4_es_status(&orig_es));
-                       err = __es_insert_extent(inode, &newes);
+                       err = __es_insert_extent(inode, &newes, NULL);
                        if (err) {
                                es->es_lblk = orig_es.es_lblk;
                                es->es_len = orig_es.es_len;
@@ -2016,7 +2021,7 @@ int ext4_es_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk,
        if (err != 0)
                goto error;
 retry:
-       err = __es_insert_extent(inode, &newes);
+       err = __es_insert_extent(inode, &newes, NULL);
        if (err == -ENOMEM && __es_shrink(EXT4_SB(inode->i_sb),
                                          128, EXT4_I(inode)))
                goto retry;