Patch "btrfs: clarify error returns values in __load_free_space_cache" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    btrfs: clarify error returns values in __load_free_space_cache

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     btrfs-clarify-error-returns-values-in-__load_free_sp.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit d1711e861da4d2b1133610e116e7bf2165d792fa
Author: Zhihao Cheng <chengzhihao1@xxxxxxxxxx>
Date:   Fri Nov 20 09:08:04 2020 +0800

    btrfs: clarify error returns values in __load_free_space_cache
    
    [ Upstream commit 3cc64e7ebfb0d7faaba2438334c43466955a96e8 ]
    
    Return value in __load_free_space_cache is not properly set after
    (unlikely) memory allocation failures and 0 is returned instead.
    This is not a problem for the caller load_free_space_cache because only
    value 1 is considered as 'cache loaded' but for clarity it's better
    to set the errors accordingly.
    
    Fixes: a67509c30079 ("Btrfs: add a io_ctl struct and helpers for dealing with the space cache")
    Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
    Signed-off-by: Zhihao Cheng <chengzhihao1@xxxxxxxxxx>
    Reviewed-by: David Sterba <dsterba@xxxxxxxx>
    Signed-off-by: David Sterba <dsterba@xxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 6e6be922b937d..23f59d463e24e 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -744,8 +744,10 @@ static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 	while (num_entries) {
 		e = kmem_cache_zalloc(btrfs_free_space_cachep,
 				      GFP_NOFS);
-		if (!e)
+		if (!e) {
+			ret = -ENOMEM;
 			goto free_cache;
+		}
 
 		ret = io_ctl_read_entry(&io_ctl, e, &type);
 		if (ret) {
@@ -754,6 +756,7 @@ static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 		}
 
 		if (!e->bytes) {
+			ret = -1;
 			kmem_cache_free(btrfs_free_space_cachep, e);
 			goto free_cache;
 		}
@@ -774,6 +777,7 @@ static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 			e->bitmap = kmem_cache_zalloc(
 					btrfs_free_space_bitmap_cachep, GFP_NOFS);
 			if (!e->bitmap) {
+				ret = -ENOMEM;
 				kmem_cache_free(
 					btrfs_free_space_cachep, e);
 				goto free_cache;