No upstream commit exists for this patch. bkey sizes are stored in sectors as u32, while fiemap reports byte lengths as u64. Shifting k.k->size before widening performs the conversion in 32 bits, so an extent of 4 GiB or larger can wrap before it is passed to fiemap_fill_next_extent().
Compute the byte length after casting the sector count to u64 and reuse it for all bch2_fill_extent() cases. The same issue was fixed in bcachefs-tools, but there is no Linux upstream commit to backport to 6.12. The affected 6.12 implementation lives in fs/bcachefs/fs.c, while the bcachefs-tools fix touches fs/bcachefs/vfs/fiemap.c. Found by Linux Verification Center (linuxtesting.org) with SVACE. Link: https://lore.kernel.org/linux-bcachefs/[email protected]/ Link: https://evilpiepirate.org/git/bcachefs-tools.git/commit/?id=6d9a895ed00d4b3868312df93253d2a817b0c6a3 Signed-off-by: Mikhail Dmitrichenko <[email protected]> --- fs/bcachefs/fs.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c index a41d0d8a2f7b..0dc2466de3f9 100644 --- a/fs/bcachefs/fs.c +++ b/fs/bcachefs/fs.c @@ -1184,6 +1184,8 @@ static int bch2_fill_extent(struct bch_fs *c, struct fiemap_extent_info *info, struct bkey_s_c k, unsigned flags) { + u64 len = (u64)k.k->size << 9; + if (bkey_extent_is_direct_data(k.k)) { struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k); const union bch_extent_entry *entry; @@ -1212,7 +1214,7 @@ static int bch2_fill_extent(struct bch_fs *c, ret = fiemap_fill_next_extent(info, bkey_start_offset(k.k) << 9, offset << 9, - k.k->size << 9, flags|flags2); + len, flags | flags2); if (ret) return ret; } @@ -1221,13 +1223,13 @@ static int bch2_fill_extent(struct bch_fs *c, } else if (bkey_extent_is_inline_data(k.k)) { return fiemap_fill_next_extent(info, bkey_start_offset(k.k) << 9, - 0, k.k->size << 9, + 0, len, flags| FIEMAP_EXTENT_DATA_INLINE); } else if (k.k->type == KEY_TYPE_reservation) { return fiemap_fill_next_extent(info, bkey_start_offset(k.k) << 9, - 0, k.k->size << 9, + 0, len, flags| FIEMAP_EXTENT_DELALLOC| FIEMAP_EXTENT_UNWRITTEN); -- 2.43.0
