| Message ID | 20250306105900.1961011-1-maharmstone@fb.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | btrfs: avoid linker error in btrfs_find_create_tree_block() | expand |
The context to this is that I'm fed up of seeing "<optimized out>" in GDB, and am trying to get the kernel to compile with -O0 for development purposes. There's still a couple of issues elsewhere for this to be possible, but this was one of the problems I ran into. Mark On 6/3/25 10:58, Mark Harmstone wrote: > The inline function btrfs_is_testing() is hardcoded to return 0 if > CONFIG_BTRFS_FS_RUN_SANITY_TESTS is not set. Currently we're relying on > the compiler optimizing out the call to alloc_test_extent_buffer() in > btrfs_find_create_tree_block(), as it's not been defined (it's behind an > #ifdef). > > Add a stub version of alloc_test_extent_buffer() to avoid linker errors > on non-standard optimization levels. This problem was seen on GCC 14 > with -O0. > > Signed-off-by: Mark Harmstone <maharmstone@fb.com> > --- > fs/btrfs/extent_io.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c > index fad42da1a6ba..03320f953817 100644 > --- a/fs/btrfs/extent_io.c > +++ b/fs/btrfs/extent_io.c > @@ -2984,10 +2984,10 @@ struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info, > return eb; > } > > -#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS > struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info, > u64 start) > { > +#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS > struct extent_buffer *eb, *exists = NULL; > int ret; > > @@ -3023,8 +3023,14 @@ struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info, > free_eb: > btrfs_release_extent_buffer(eb); > return exists; > -} > +#else > + /* > + * stub to avoid linker error when compiled with optimizations > + * turned off > + */ > + return NULL; > #endif > +} > > static struct extent_buffer *grab_extent_buffer(struct btrfs_fs_info *fs_info, > struct folio *folio)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index fad42da1a6ba..03320f953817 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -2984,10 +2984,10 @@ struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info, return eb; } -#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info, u64 start) { +#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS struct extent_buffer *eb, *exists = NULL; int ret; @@ -3023,8 +3023,14 @@ struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info, free_eb: btrfs_release_extent_buffer(eb); return exists; -} +#else + /* + * stub to avoid linker error when compiled with optimizations + * turned off + */ + return NULL; #endif +} static struct extent_buffer *grab_extent_buffer(struct btrfs_fs_info *fs_info, struct folio *folio)
The inline function btrfs_is_testing() is hardcoded to return 0 if CONFIG_BTRFS_FS_RUN_SANITY_TESTS is not set. Currently we're relying on the compiler optimizing out the call to alloc_test_extent_buffer() in btrfs_find_create_tree_block(), as it's not been defined (it's behind an #ifdef). Add a stub version of alloc_test_extent_buffer() to avoid linker errors on non-standard optimization levels. This problem was seen on GCC 14 with -O0. Signed-off-by: Mark Harmstone <maharmstone@fb.com> --- fs/btrfs/extent_io.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)