erofs: address D-cache aliasing

Flush the D-cache before unlocking folios for compressed inodes, as
they are dirtied during decompression.

Avoid calling flush_dcache_folio() on every CPU write, since it's more
like playing whack-a-mole without real benefit.

It has no impact on x86 and arm64/risc-v: on x86, flush_dcache_folio()
is a no-op, and on arm64/risc-v, PG_dcache_clean (PG_arch_1) is clear
for new page cache folios.  However, certain ARM boards are affected,
as reported.

Fixes: 3883a79abd ("staging: erofs: introduce VLE decompression support")
Closes: https://lore.kernel.org/r/c1e51e16-6cc6-49d0-a63e-4e9ff6c4dd53@pengutronix.de
Closes: https://lore.kernel.org/r/38d43fae-1182-4155-9c5b-ffc7382d9917@siemens.com
Tested-by: Jan Kiszka <jan.kiszka@siemens.com>
Tested-by: Stefan Kerkmann <s.kerkmann@pengutronix.de>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250709034614.2780117-2-hsiangkao@linux.alibaba.com
This commit is contained in:
Gao Xiang 2025-07-09 11:46:14 +08:00
parent f5443d0d1a
commit 27917e8194
5 changed files with 21 additions and 19 deletions

View file

@ -214,9 +214,11 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
/*
* bit 30: I/O error occurred on this folio
* bit 29: CPU has dirty data in D-cache (needs aliasing handling);
* bit 0 - 29: remaining parts to complete this folio
*/
#define EROFS_ONLINEFOLIO_EIO (1 << 30)
#define EROFS_ONLINEFOLIO_EIO 30
#define EROFS_ONLINEFOLIO_DIRTY 29
void erofs_onlinefolio_init(struct folio *folio)
{
@ -233,19 +235,23 @@ void erofs_onlinefolio_split(struct folio *folio)
atomic_inc((atomic_t *)&folio->private);
}
void erofs_onlinefolio_end(struct folio *folio, int err)
void erofs_onlinefolio_end(struct folio *folio, int err, bool dirty)
{
int orig, v;
do {
orig = atomic_read((atomic_t *)&folio->private);
v = (orig - 1) | (err ? EROFS_ONLINEFOLIO_EIO : 0);
DBG_BUGON(orig <= 0);
v = dirty << EROFS_ONLINEFOLIO_DIRTY;
v |= (orig - 1) | (!!err << EROFS_ONLINEFOLIO_EIO);
} while (atomic_cmpxchg((atomic_t *)&folio->private, orig, v) != orig);
if (v & ~EROFS_ONLINEFOLIO_EIO)
if (v & (BIT(EROFS_ONLINEFOLIO_DIRTY) - 1))
return;
folio->private = 0;
folio_end_read(folio, !(v & EROFS_ONLINEFOLIO_EIO));
if (v & BIT(EROFS_ONLINEFOLIO_DIRTY))
flush_dcache_folio(folio);
folio_end_read(folio, !(v & BIT(EROFS_ONLINEFOLIO_EIO)));
}
static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,

View file

@ -301,13 +301,11 @@ static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq,
cur = min(cur, rq->outputsize);
if (cur && rq->out[0]) {
kin = kmap_local_page(rq->in[nrpages_in - 1]);
if (rq->out[0] == rq->in[nrpages_in - 1]) {
if (rq->out[0] == rq->in[nrpages_in - 1])
memmove(kin + rq->pageofs_out, kin + pi, cur);
flush_dcache_page(rq->out[0]);
} else {
else
memcpy_to_page(rq->out[0], rq->pageofs_out,
kin + pi, cur);
}
kunmap_local(kin);
}
rq->outputsize -= cur;
@ -325,14 +323,12 @@ static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq,
po = (rq->pageofs_out + cur + pi) & ~PAGE_MASK;
DBG_BUGON(no >= nrpages_out);
cnt = min(insz - pi, PAGE_SIZE - po);
if (rq->out[no] == rq->in[ni]) {
if (rq->out[no] == rq->in[ni])
memmove(kin + po,
kin + rq->pageofs_in + pi, cnt);
flush_dcache_page(rq->out[no]);
} else if (rq->out[no]) {
else if (rq->out[no])
memcpy_to_page(rq->out[no], po,
kin + rq->pageofs_in + pi, cnt);
}
pi += cnt;
} while (pi < insz);
kunmap_local(kin);

View file

@ -38,7 +38,7 @@ static void erofs_fileio_ki_complete(struct kiocb *iocb, long ret)
} else {
bio_for_each_folio_all(fi, &rq->bio) {
DBG_BUGON(folio_test_uptodate(fi.folio));
erofs_onlinefolio_end(fi.folio, ret);
erofs_onlinefolio_end(fi.folio, ret, false);
}
}
bio_uninit(&rq->bio);
@ -154,7 +154,7 @@ io_retry:
}
cur += len;
}
erofs_onlinefolio_end(folio, err);
erofs_onlinefolio_end(folio, err, false);
return err;
}

View file

@ -390,7 +390,7 @@ int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
int erofs_map_blocks(struct inode *inode, struct erofs_map_blocks *map);
void erofs_onlinefolio_init(struct folio *folio);
void erofs_onlinefolio_split(struct folio *folio);
void erofs_onlinefolio_end(struct folio *folio, int err);
void erofs_onlinefolio_end(struct folio *folio, int err, bool dirty);
struct inode *erofs_iget(struct super_block *sb, erofs_nid_t nid);
int erofs_getattr(struct mnt_idmap *idmap, const struct path *path,
struct kstat *stat, u32 request_mask,

View file

@ -1091,7 +1091,7 @@ static int z_erofs_scan_folio(struct z_erofs_frontend *f,
tight = (bs == PAGE_SIZE);
}
} while ((end = cur) > 0);
erofs_onlinefolio_end(folio, err);
erofs_onlinefolio_end(folio, err, false);
return err;
}
@ -1196,7 +1196,7 @@ static void z_erofs_fill_other_copies(struct z_erofs_backend *be, int err)
cur += len;
}
kunmap_local(dst);
erofs_onlinefolio_end(page_folio(bvi->bvec.page), err);
erofs_onlinefolio_end(page_folio(bvi->bvec.page), err, true);
list_del(p);
kfree(bvi);
}
@ -1355,7 +1355,7 @@ static int z_erofs_decompress_pcluster(struct z_erofs_backend *be, int err)
DBG_BUGON(z_erofs_page_is_invalidated(page));
if (!z_erofs_is_shortlived_page(page)) {
erofs_onlinefolio_end(page_folio(page), err);
erofs_onlinefolio_end(page_folio(page), err, true);
continue;
}
if (pcl->algorithmformat != Z_EROFS_COMPRESSION_LZ4) {