commit 27917e8194f91dffd8b4825350c63cb68e98ce58 upstream.

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: 3883a79abd02 ("staging: erofs: introduce VLE decompression support") Closes: https://lore.kernel.org/r/c1e51e16-6cc6-49d0-a63e-4e9ff6c4dd53@pengutronix.d... 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 Link: https://lore.kernel.org/r/20250709034614.2780117-2-hsiangkao@linux.alibaba.c... Signed-off-by: Gao Xiang hsiangkao@linux.alibaba.com --- Hi Jan & Stefan, Please help confirm this 6.6 fix backport if possible.

Thanks, Gao Xiang

fs/erofs/decompressor.c | 6 ++---- fs/erofs/zdata.c | 32 +++++++++++++++++++------------- 2 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c index aa59788a61e6..86e088fd386e 100644 --- a/fs/erofs/decompressor.c +++ b/fs/erofs/decompressor.c @@ -342,14 +342,12 @@ static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq,

if (outpages > inpages) { DBG_BUGON(!rq->out[outpages - 1]); - if (rq->out[outpages - 1] != rq->in[inpages - 1]) { + if (rq->out[outpages - 1] != rq->in[inpages - 1]) memcpy_to_page(rq->out[outpages - 1], 0, src + (interlaced_offset ? 0 : righthalf), lefthalf); - } else if (!interlaced_offset) { + else if (!interlaced_offset) memmove(src, src + righthalf, lefthalf); - flush_dcache_page(rq->in[inpages - 1]); - } } kunmap_local(src); return 0; diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index 496e4c7c52a4..d852b43ac43e 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -122,9 +122,11 @@ static inline unsigned int z_erofs_pclusterpages(struct z_erofs_pcluster *pcl)

/* * bit 30: I/O error occurred on this page + * bit 29: CPU has dirty data in D-cache (needs aliasing handling); * bit 0 - 29: remaining parts to complete this page */ -#define Z_EROFS_PAGE_EIO (1 << 30) +#define Z_EROFS_ONLINEPAGE_EIO 30 +#define Z_EROFS_ONLINEPAGE_DIRTY 29

static inline void z_erofs_onlinepage_init(struct page *page) { @@ -143,7 +145,7 @@ static inline void z_erofs_onlinepage_split(struct page *page) atomic_inc((atomic_t *)&page->private); }

-static void z_erofs_onlinepage_endio(struct page *page, int err) +static void z_erofs_onlinepage_end(struct page *page, int err, bool dirty) { int orig, v;

@@ -151,16 +153,20 @@ static void z_erofs_onlinepage_endio(struct page *page, int err)

do { orig = atomic_read((atomic_t *)&page->private); - v = (orig - 1) | (err ? Z_EROFS_PAGE_EIO : 0); + DBG_BUGON(orig <= 0); + v = dirty << Z_EROFS_ONLINEPAGE_DIRTY; + v |= (orig - 1) | (!!err << Z_EROFS_ONLINEPAGE_EIO); } while (atomic_cmpxchg((atomic_t *)&page->private, orig, v) != orig);

- if (!(v & ~Z_EROFS_PAGE_EIO)) { - set_page_private(page, 0); - ClearPagePrivate(page); - if (!(v & Z_EROFS_PAGE_EIO)) - SetPageUptodate(page); - unlock_page(page); - } + if (v & (BIT(Z_EROFS_ONLINEPAGE_DIRTY) - 1)) + return; + set_page_private(page, 0); + ClearPagePrivate(page); + if (v & BIT(Z_EROFS_ONLINEPAGE_DIRTY)) + flush_dcache_page(page); + if (!(v & BIT(Z_EROFS_ONLINEPAGE_EIO))) + SetPageUptodate(page); + unlock_page(page); }

#define Z_EROFS_ONSTACK_PAGES 32 @@ -1060,7 +1066,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe, goto repeat;

out: - z_erofs_onlinepage_endio(page, err); + z_erofs_onlinepage_end(page, err, false); return err; }

@@ -1163,7 +1169,7 @@ static void z_erofs_fill_other_copies(struct z_erofs_decompress_backend *be, cur += len; } kunmap_local(dst); - z_erofs_onlinepage_endio(bvi->bvec.page, err); + z_erofs_onlinepage_end(bvi->bvec.page, err, true); list_del(p); kfree(bvi); } @@ -1333,7 +1339,7 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be, /* recycle all individual short-lived pages */ if (z_erofs_put_shortlivedpage(be->pagepool, page)) continue; - z_erofs_onlinepage_endio(page, err); + z_erofs_onlinepage_end(page, err, true); }

if (be->decompressed_pages != be->onstack_pages)