gcc is unsure about the use of last_ofs_in_node, which might happen
without a prior initialization:
fs/f2fs//git/arm-soc/fs/f2fs/data.c: In function ‘f2fs_map_blocks’:
fs/f2fs/data.c:799:54: warning: ‘last_ofs_in_node’ may be used uninitialized in
this function [-Wmaybe-uninitialized]
if (prealloc && dn.ofs_in_node != last_ofs_in_node + 1) {
As pointed out by Chao Yu, the code is actually correct as 'prealloc'
is only set if the last_ofs_in_node has been set, the two always
get updated together.
This initializes last_ofs_in_node to dn.ofs_in_node for each
new dnode at the start of the 'next_block' loop, which at that
point is a correct initialization as well. I assume that compilers
that correctly track the contents of the variables and do not
warn about the condition also figure out that they can eliminate
the extra assignment here.
Fixes: 46008c6d4232 ("f2fs: support in batch multi blocks preallocation")
Signed-off-by: Arnd Bergmann <[email protected]>
---
fs/f2fs/data.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
v2: use simpler workaround, as discussed with Chao Yu.
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 68edb47f5f71..cf5ec39f907d 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -713,7 +713,7 @@ int f2fs_map_blocks(struct inode *inode, struct
f2fs_map_blocks *map,
}
prealloc = 0;
- ofs_in_node = dn.ofs_in_node;
+ last_ofs_in_node = ofs_in_node = dn.ofs_in_node;
end_offset = ADDRS_PER_PAGE(dn.node_page, inode);
next_block:
--
2.9.0
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