| Message ID | 20190322140753.286171-1-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
| Series | btrfs: work around false-positive -Wsometimes-uninitialized warning | expand |
On 22.03.19 г. 16:07 ч., Arnd Bergmann wrote: > clang fails to see that the last 'else if() in btrfs_uuid_tree_add() > is always true, so 'eb' is always initialized correctly: > > fs/btrfs/uuid-tree.c:129:13: error: variable 'eb' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized] > } else if (ret < 0) { > ^~~~~~~ > fs/btrfs/uuid-tree.c:139:22: note: uninitialized use occurs here > write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le)); > ^~ > fs/btrfs/uuid-tree.c:129:9: note: remove the 'if' if its condition is always true > } else if (ret < 0) { > ^~~~~~~~~~~~~ > fs/btrfs/uuid-tree.c:90:26: note: initialize the variable 'eb' to silence this warning > struct extent_buffer *eb; > ^ > = NULL > > Change it into a plain 'else' to shut up that warning. > > Link: https://bugs.llvm.org/show_bug.cgi?id=41197 > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Such a patch has already been merged to misc-next: f22898caa6a5 ("btrfs: Turn an 'else if' into an 'else' in btrfs_uuid_tree_add") > --- > fs/btrfs/uuid-tree.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/btrfs/uuid-tree.c b/fs/btrfs/uuid-tree.c > index 3b2ae342e649..c1cc9a5c0024 100644 > --- a/fs/btrfs/uuid-tree.c > +++ b/fs/btrfs/uuid-tree.c > @@ -126,7 +126,7 @@ int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans, u8 *uuid, u8 type, > slot = path->slots[0]; > offset = btrfs_item_ptr_offset(eb, slot); > offset += btrfs_item_size_nr(eb, slot) - sizeof(subid_le); > - } else if (ret < 0) { > + } else { > btrfs_warn(fs_info, > "insert uuid item failed %d (0x%016llx, 0x%016llx) type %u!", > ret, (unsigned long long)key.objectid, >
On Fri, Mar 22, 2019 at 04:11:52PM +0200, Nikolay Borisov wrote: > > > On 22.03.19 г. 16:07 ч., Arnd Bergmann wrote: > > clang fails to see that the last 'else if() in btrfs_uuid_tree_add() > > is always true, so 'eb' is always initialized correctly: > > > > fs/btrfs/uuid-tree.c:129:13: error: variable 'eb' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized] > > } else if (ret < 0) { > > ^~~~~~~ > > fs/btrfs/uuid-tree.c:139:22: note: uninitialized use occurs here > > write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le)); > > ^~ > > fs/btrfs/uuid-tree.c:129:9: note: remove the 'if' if its condition is always true > > } else if (ret < 0) { > > ^~~~~~~~~~~~~ > > fs/btrfs/uuid-tree.c:90:26: note: initialize the variable 'eb' to silence this warning > > struct extent_buffer *eb; > > ^ > > = NULL > > > > Change it into a plain 'else' to shut up that warning. > > > > Link: https://bugs.llvm.org/show_bug.cgi?id=41197 > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > > Such a patch has already been merged to misc-next: > > f22898caa6a5 ("btrfs: Turn an 'else if' into an 'else' in > btrfs_uuid_tree_add") I haven't updated for-next for a few days so the patch was not so visible outside, will push an update today.
diff --git a/fs/btrfs/uuid-tree.c b/fs/btrfs/uuid-tree.c index 3b2ae342e649..c1cc9a5c0024 100644 --- a/fs/btrfs/uuid-tree.c +++ b/fs/btrfs/uuid-tree.c @@ -126,7 +126,7 @@ int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans, u8 *uuid, u8 type, slot = path->slots[0]; offset = btrfs_item_ptr_offset(eb, slot); offset += btrfs_item_size_nr(eb, slot) - sizeof(subid_le); - } else if (ret < 0) { + } else { btrfs_warn(fs_info, "insert uuid item failed %d (0x%016llx, 0x%016llx) type %u!", ret, (unsigned long long)key.objectid,
clang fails to see that the last 'else if() in btrfs_uuid_tree_add() is always true, so 'eb' is always initialized correctly: fs/btrfs/uuid-tree.c:129:13: error: variable 'eb' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized] } else if (ret < 0) { ^~~~~~~ fs/btrfs/uuid-tree.c:139:22: note: uninitialized use occurs here write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le)); ^~ fs/btrfs/uuid-tree.c:129:9: note: remove the 'if' if its condition is always true } else if (ret < 0) { ^~~~~~~~~~~~~ fs/btrfs/uuid-tree.c:90:26: note: initialize the variable 'eb' to silence this warning struct extent_buffer *eb; ^ = NULL Change it into a plain 'else' to shut up that warning. Link: https://bugs.llvm.org/show_bug.cgi?id=41197 Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- fs/btrfs/uuid-tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.20.0