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erofs: support unaligned encoded data

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We're almost there.  It's straight-forward to adapt the current
decompression subsystem to support unaligned encoded (compressed) data.

Note that unaligned data is not encouraged because of worse I/O and
caching efficiency unless the corresponding compressor doesn't support
fixed-sized output compression natively like Zstd.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Acked-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20250310095459.2620647-10-hsiangkao@linux.alibaba.com
This commit is contained in:
Gao Xiang 2025-03-10 17:54:59 +08:00
parent 1d191b4ca5
commit 7361d1e376
2 changed files with 46 additions and 48 deletions
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2
fs/erofs/decompressor.c
View File

@ -313,7 +313,7 @@ static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq,
rq->outputsize -= cur;
}
for (; rq->outputsize; rq->pageofs_in = 0, cur += PAGE_SIZE, ni++) {
for (; rq->outputsize; rq->pageofs_in = 0, cur += insz, ni++) {
insz = min(PAGE_SIZE - rq->pageofs_in, rq->outputsize);
rq->outputsize -= insz;
if (!rq->in[ni])

92
fs/erofs/zdata.c
View File

@ -44,8 +44,8 @@ struct z_erofs_pcluster {
/* A: point to next chained pcluster or TAILs */
struct z_erofs_pcluster *next;
/* I: start block address of this pcluster */
erofs_off_t index;
/* I: start physical position of this pcluster */
erofs_off_t pos;
/* L: the maximum decompression size of this round */
unsigned int length;
@ -73,6 +73,9 @@ struct z_erofs_pcluster {
/* I: compression algorithm format */
unsigned char algorithmformat;
/* I: whether compressed data is in-lined or not */
bool from_meta;
/* L: whether partial decompression or not */
bool partial;
@ -102,14 +105,9 @@ struct z_erofs_decompressqueue {
bool eio, sync;
};
static inline bool z_erofs_is_inline_pcluster(struct z_erofs_pcluster *pcl)
{
return !pcl->index;
}
static inline unsigned int z_erofs_pclusterpages(struct z_erofs_pcluster *pcl)
{
return PAGE_ALIGN(pcl->pclustersize) >> PAGE_SHIFT;
return PAGE_ALIGN(pcl->pageofs_in + pcl->pclustersize) >> PAGE_SHIFT;
}
static bool erofs_folio_is_managed(struct erofs_sb_info *sbi, struct folio *fo)
@ -133,7 +131,7 @@ struct z_erofs_pcluster_slab {
static struct z_erofs_pcluster_slab pcluster_pool[] __read_mostly = {
_PCLP(1), _PCLP(4), _PCLP(16), _PCLP(64), _PCLP(128),
_PCLP(Z_EROFS_PCLUSTER_MAX_PAGES)
_PCLP(Z_EROFS_PCLUSTER_MAX_PAGES + 1)
};
struct z_erofs_bvec_iter {
@ -267,7 +265,6 @@ static struct z_erofs_pcluster *z_erofs_alloc_pcluster(unsigned int size)
pcl = kmem_cache_zalloc(pcs->slab, GFP_KERNEL);
if (!pcl)
return ERR_PTR(-ENOMEM);
pcl->pclustersize = size;
return pcl;
}
return ERR_PTR(-EINVAL);
@ -516,6 +513,7 @@ static void z_erofs_bind_cache(struct z_erofs_frontend *fe)
struct z_erofs_pcluster *pcl = fe->pcl;
unsigned int pclusterpages = z_erofs_pclusterpages(pcl);
bool shouldalloc = z_erofs_should_alloc_cache(fe);
pgoff_t poff = pcl->pos >> PAGE_SHIFT;
bool may_bypass = true;
/* Optimistic allocation, as in-place I/O can be used as a fallback */
gfp_t gfp = (mapping_gfp_mask(mc) & ~__GFP_DIRECT_RECLAIM) |
@ -532,7 +530,7 @@ static void z_erofs_bind_cache(struct z_erofs_frontend *fe)
if (READ_ONCE(pcl->compressed_bvecs[i].page))
continue;
folio = filemap_get_folio(mc, pcl->index + i);
folio = filemap_get_folio(mc, poff + i);
if (IS_ERR(folio)) {
may_bypass = false;
if (!shouldalloc)
@ -575,7 +573,7 @@ static int erofs_try_to_free_all_cached_folios(struct erofs_sb_info *sbi,
struct folio *folio;
int i;
DBG_BUGON(z_erofs_is_inline_pcluster(pcl));
DBG_BUGON(pcl->from_meta);
/* Each cached folio contains one page unless bs > ps is supported */
for (i = 0; i < pclusterpages; ++i) {
if (pcl->compressed_bvecs[i].page) {
@ -607,7 +605,7 @@ static bool z_erofs_cache_release_folio(struct folio *folio, gfp_t gfp)
ret = false;
spin_lock(&pcl->lockref.lock);
if (pcl->lockref.count <= 0) {
DBG_BUGON(z_erofs_is_inline_pcluster(pcl));
DBG_BUGON(pcl->from_meta);
for (; bvec < end; ++bvec) {
if (bvec->page && page_folio(bvec->page) == folio) {
bvec->page = NULL;
@ -667,16 +665,20 @@ static int z_erofs_attach_page(struct z_erofs_frontend *fe,
int ret;
if (exclusive) {
/* give priority for inplaceio to use file pages first */
spin_lock(&pcl->lockref.lock);
while (fe->icur > 0) {
if (pcl->compressed_bvecs[--fe->icur].page)
continue;
pcl->compressed_bvecs[fe->icur] = *bvec;
/* Inplace I/O is limited to one page for uncompressed data */
if (pcl->algorithmformat < Z_EROFS_COMPRESSION_MAX ||
fe->icur <= 1) {
/* Try to prioritize inplace I/O here */
spin_lock(&pcl->lockref.lock);
while (fe->icur > 0) {
if (pcl->compressed_bvecs[--fe->icur].page)
continue;
pcl->compressed_bvecs[fe->icur] = *bvec;
spin_unlock(&pcl->lockref.lock);
return 0;
}
spin_unlock(&pcl->lockref.lock);
return 0;
}
spin_unlock(&pcl->lockref.lock);
/* otherwise, check if it can be used as a bvpage */
if (fe->mode >= Z_EROFS_PCLUSTER_FOLLOWED &&
@ -711,27 +713,26 @@ static int z_erofs_register_pcluster(struct z_erofs_frontend *fe)
struct erofs_map_blocks *map = &fe->map;
struct super_block *sb = fe->inode->i_sb;
struct erofs_sb_info *sbi = EROFS_SB(sb);
bool ztailpacking = map->m_flags & EROFS_MAP_META;
struct z_erofs_pcluster *pcl, *pre;
unsigned int pageofs_in;
int err;
if (!(map->m_flags & EROFS_MAP_ENCODED) ||
(!ztailpacking && !erofs_blknr(sb, map->m_pa))) {
DBG_BUGON(1);
return -EFSCORRUPTED;
}
/* no available pcluster, let's allocate one */
pcl = z_erofs_alloc_pcluster(map->m_plen);
pageofs_in = erofs_blkoff(sb, map->m_pa);
pcl = z_erofs_alloc_pcluster(pageofs_in + map->m_plen);
if (IS_ERR(pcl))
return PTR_ERR(pcl);
lockref_init(&pcl->lockref); /* one ref for this request */
pcl->algorithmformat = map->m_algorithmformat;
pcl->pclustersize = map->m_plen;
pcl->pageofs_in = pageofs_in;
pcl->length = 0;
pcl->partial = true;
pcl->next = fe->head;
pcl->pos = map->m_pa;
pcl->pageofs_in = pageofs_in;
pcl->pageofs_out = map->m_la & ~PAGE_MASK;
pcl->from_meta = map->m_flags & EROFS_MAP_META;
fe->mode = Z_EROFS_PCLUSTER_FOLLOWED;
/*
@ -741,13 +742,10 @@ static int z_erofs_register_pcluster(struct z_erofs_frontend *fe)
mutex_init(&pcl->lock);
DBG_BUGON(!mutex_trylock(&pcl->lock));
if (ztailpacking) {
pcl->index = 0; /* which indicates ztailpacking */
} else {
pcl->index = erofs_blknr(sb, map->m_pa);
if (!pcl->from_meta) {
while (1) {
xa_lock(&sbi->managed_pslots);
pre = __xa_cmpxchg(&sbi->managed_pslots, pcl->index,
pre = __xa_cmpxchg(&sbi->managed_pslots, pcl->pos,
NULL, pcl, GFP_KERNEL);
if (!pre || xa_is_err(pre) || z_erofs_get_pcluster(pre)) {
xa_unlock(&sbi->managed_pslots);
@ -779,7 +777,6 @@ static int z_erofs_pcluster_begin(struct z_erofs_frontend *fe)
{
struct erofs_map_blocks *map = &fe->map;
struct super_block *sb = fe->inode->i_sb;
erofs_blk_t blknr = erofs_blknr(sb, map->m_pa);
struct z_erofs_pcluster *pcl = NULL;
int ret;
@ -790,9 +787,9 @@ static int z_erofs_pcluster_begin(struct z_erofs_frontend *fe)
if (!(map->m_flags & EROFS_MAP_META)) {
while (1) {
rcu_read_lock();
pcl = xa_load(&EROFS_SB(sb)->managed_pslots, blknr);
pcl = xa_load(&EROFS_SB(sb)->managed_pslots, map->m_pa);
if (!pcl || z_erofs_get_pcluster(pcl)) {
DBG_BUGON(pcl && blknr != pcl->index);
DBG_BUGON(pcl && map->m_pa != pcl->pos);
rcu_read_unlock();
break;
}
@ -826,7 +823,7 @@ static int z_erofs_pcluster_begin(struct z_erofs_frontend *fe)
z_erofs_bvec_iter_begin(&fe->biter, &fe->pcl->bvset,
Z_EROFS_INLINE_BVECS, fe->pcl->vcnt);
if (!z_erofs_is_inline_pcluster(fe->pcl)) {
if (!fe->pcl->from_meta) {
/* bind cache first when cached decompression is preferred */
z_erofs_bind_cache(fe);
} else {
@ -871,7 +868,7 @@ static bool __erofs_try_to_release_pcluster(struct erofs_sb_info *sbi,
* It's impossible to fail after the pcluster is freezed, but in order
* to avoid some race conditions, add a DBG_BUGON to observe this.
*/
DBG_BUGON(__xa_erase(&sbi->managed_pslots, pcl->index) != pcl);
DBG_BUGON(__xa_erase(&sbi->managed_pslots, pcl->pos) != pcl);
lockref_mark_dead(&pcl->lockref);
return true;
@ -1221,7 +1218,7 @@ static int z_erofs_parse_in_bvecs(struct z_erofs_backend *be, bool *overlapped)
}
be->compressed_pages[i] = page;
if (z_erofs_is_inline_pcluster(pcl) ||
if (pcl->from_meta ||
erofs_folio_is_managed(EROFS_SB(be->sb), page_folio(page))) {
if (!PageUptodate(page))
err = -EIO;
@ -1299,7 +1296,7 @@ static int z_erofs_decompress_pcluster(struct z_erofs_backend *be, int err)
}, be->pagepool);
/* must handle all compressed pages before actual file pages */
if (z_erofs_is_inline_pcluster(pcl)) {
if (pcl->from_meta) {
page = pcl->compressed_bvecs[0].page;
WRITE_ONCE(pcl->compressed_bvecs[0].page, NULL);
put_page(page);
@ -1359,7 +1356,7 @@ static int z_erofs_decompress_pcluster(struct z_erofs_backend *be, int err)
WRITE_ONCE(pcl->next, NULL);
mutex_unlock(&pcl->lock);
if (z_erofs_is_inline_pcluster(pcl))
if (pcl->from_meta)
z_erofs_free_pcluster(pcl);
else
z_erofs_put_pcluster(sbi, pcl, try_free);
@ -1540,7 +1537,7 @@ out_allocfolio:
folio = page_folio(page);
out_tocache:
if (!tocache || bs != PAGE_SIZE ||
filemap_add_folio(mc, folio, pcl->index + nr, gfp)) {
filemap_add_folio(mc, folio, (pcl->pos >> PAGE_SHIFT) + nr, gfp)) {
/* turn into a temporary shortlived folio (1 ref) */
folio->private = (void *)Z_EROFS_SHORTLIVED_PAGE;
return;
@ -1657,19 +1654,20 @@ static void z_erofs_submit_queue(struct z_erofs_frontend *f,
pcl = next;
next = READ_ONCE(pcl->next);
if (z_erofs_is_inline_pcluster(pcl)) {
if (pcl->from_meta) {
z_erofs_move_to_bypass_queue(pcl, next, qtail);
continue;
}
/* no device id here, thus it will always succeed */
mdev = (struct erofs_map_dev) {
.m_pa = erofs_pos(sb, pcl->index),
.m_pa = round_down(pcl->pos, sb->s_blocksize),
};
(void)erofs_map_dev(sb, &mdev);
cur = mdev.m_pa;
end = cur + pcl->pclustersize;
end = round_up(cur + pcl->pageofs_in + pcl->pclustersize,
sb->s_blocksize);
do {
bvec.bv_page = NULL;
if (bio && (cur != last_pa ||