On Mon, May 27, 2024 at 09:53:45AM +0900, Ryusuke Konishi wrote: > On Mon, May 27, 2024 at 2:21 AM Sasha Levin wrote: > > > > This is a note to let you know that I've just added the patch titled > > > > nilfs2: make superblock data array index computation sparse friendly > > > > to the 6.9-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: > > nilfs2-make-superblock-data-array-index-computation-.patch > > and it can be found in the queue-6.9 subdirectory. > > > > If you, or anyone else, feels it should not be added to the stable tree, > > please let <stable@xxxxxxxxxxxxxxx> know about it. > > > > > > > > commit 5017482ff3b29550015cce7f81279dc69aefd6fe > > Author: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx> > > Date: Tue Apr 30 17:00:19 2024 +0900 > > > > nilfs2: make superblock data array index computation sparse friendly > > > > [ Upstream commit 91d743a9c8299de1fc1b47428d8bb4c85face00f ] > > > > Upon running sparse, "warning: dubious: x & !y" is output at an array > > index calculation within nilfs_load_super_block(). > > > > The calculation is not wrong, but to eliminate the sparse warning, replace > > it with an equivalent calculation. > > > > Also, add a comment to make it easier to understand what the unintuitive > > array index calculation is doing and whether it's correct. > > > > Link: https://lkml.kernel.org/r/20240430080019.4242-3-konishi.ryusuke@xxxxxxxxx > > Fixes: e339ad31f599 ("nilfs2: introduce secondary super block") > > Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx> > > Cc: Bart Van Assche <bvanassche@xxxxxxx> > > Cc: Jens Axboe <axboe@xxxxxxxxx> > > Cc: kernel test robot <lkp@xxxxxxxxx> > > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > > > > diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c > > index 2ae2c1bbf6d17..adbc6e87471ab 100644 > > --- a/fs/nilfs2/the_nilfs.c > > +++ b/fs/nilfs2/the_nilfs.c > > @@ -592,7 +592,7 @@ static int nilfs_load_super_block(struct the_nilfs *nilfs, > > struct nilfs_super_block **sbp = nilfs->ns_sbp; > > struct buffer_head **sbh = nilfs->ns_sbh; > > u64 sb2off, devsize = bdev_nr_bytes(nilfs->ns_bdev); > > - int valid[2], swp = 0; > > + int valid[2], swp = 0, older; > > > > if (devsize < NILFS_SEG_MIN_BLOCKS * NILFS_MIN_BLOCK_SIZE + 4096) { > > nilfs_err(sb, "device size too small"); > > @@ -648,9 +648,25 @@ static int nilfs_load_super_block(struct the_nilfs *nilfs, > > if (swp) > > nilfs_swap_super_block(nilfs); > > > > + /* > > + * Calculate the array index of the older superblock data. > > + * If one has been dropped, set index 0 pointing to the remaining one, > > + * otherwise set index 1 pointing to the old one (including if both > > + * are the same). > > + * > > + * Divided case valid[0] valid[1] swp -> older > > + * ------------------------------------------------------------- > > + * Both SBs are invalid 0 0 N/A (Error) > > + * SB1 is invalid 0 1 1 0 > > + * SB2 is invalid 1 0 0 0 > > + * SB2 is newer 1 1 1 0 > > + * SB2 is older or the same 1 1 0 1 > > + */ > > + older = valid[1] ^ swp; > > + > > nilfs->ns_sbwcount = 0; > > nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime); > > - nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq); > > + nilfs->ns_prot_seq = le64_to_cpu(sbp[older]->s_last_seq); > > *sbpp = sbp[0]; > > return 0; > > } > > This commit fixes the sparse warning output by build "make C=1" with > the sparse check, but does not fix any operational bugs. > > Therefore, if fixing a harmless sparse warning does not meet the > requirements for backporting to stable trees (I assume it does), > please drop it as it is a false positive pickup. Sorry if the > "Fixes:" tag is confusing. > > The same goes for the same patch queued to other stable-trees. Now dropped, thanks! greg k-h
