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Message-ID: <20240905084732.2684515-1-hsiangkao@linux.alibaba.com>
Date: Thu, 5 Sep 2024 16:47:32 +0800
From: Gao Xiang <hsiangkao@...ux.alibaba.com>
To: linux-erofs@...ts.ozlabs.org
Cc: LKML <linux-kernel@...r.kernel.org>,
Gao Xiang <hsiangkao@...ux.alibaba.com>
Subject: [PATCH] erofs: sunset unneeded NOFAILs
With iterative development, our codebase can now deal with compressed
buffer misses properly if both in-place I/O and compressed buffer
allocation fail.
Note that if readahead fails (with non-uptodate folios), the original
request will then fall back to synchronous read, and `.read_folio()`
should return appropriate errnos; otherwise -EIO will be passed to
user space, which is unexpected.
To simplify rarely encountered failure paths, a mimic decompression
will be just used. Before that, failure reasons are recorded in
compressed_bvecs[] and they also act as placeholders to avoid in-place
pages. They will be parsed just before decompression and then pass
back to `.read_folio()`.
Signed-off-by: Gao Xiang <hsiangkao@...ux.alibaba.com>
---
fs/erofs/zdata.c | 57 ++++++++++++++++++++++++++----------------------
1 file changed, 31 insertions(+), 26 deletions(-)
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 785ae6ca77b1..ad0b59b3d23e 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -1154,9 +1154,10 @@ static int z_erofs_parse_in_bvecs(struct z_erofs_decompress_backend *be,
struct z_erofs_bvec *bvec = &pcl->compressed_bvecs[i];
struct page *page = bvec->page;
- /* compressed data ought to be valid before decompressing */
- if (!page) {
- err = -EIO;
+ /* compressed data ought to be valid when decompressing */
+ if (IS_ERR(page) || !page) {
+ bvec->page = NULL; /* clear the failure reason */
+ err = page ? PTR_ERR(page) : -EIO;
continue;
}
be->compressed_pages[i] = page;
@@ -1232,8 +1233,7 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be,
.inplace_io = overlapped,
.partial_decoding = pcl->partial,
.fillgaps = pcl->multibases,
- .gfp = pcl->besteffort ?
- GFP_KERNEL | __GFP_NOFAIL :
+ .gfp = pcl->besteffort ? GFP_KERNEL :
GFP_NOWAIT | __GFP_NORETRY
}, be->pagepool);
@@ -1297,8 +1297,8 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be,
return err;
}
-static void z_erofs_decompress_queue(const struct z_erofs_decompressqueue *io,
- struct page **pagepool)
+static int z_erofs_decompress_queue(const struct z_erofs_decompressqueue *io,
+ struct page **pagepool)
{
struct z_erofs_decompress_backend be = {
.sb = io->sb,
@@ -1307,6 +1307,7 @@ static void z_erofs_decompress_queue(const struct z_erofs_decompressqueue *io,
LIST_HEAD_INIT(be.decompressed_secondary_bvecs),
};
z_erofs_next_pcluster_t owned = io->head;
+ int err = io->eio ? -EIO : 0;
while (owned != Z_EROFS_PCLUSTER_TAIL) {
DBG_BUGON(owned == Z_EROFS_PCLUSTER_NIL);
@@ -1314,12 +1315,13 @@ static void z_erofs_decompress_queue(const struct z_erofs_decompressqueue *io,
be.pcl = container_of(owned, struct z_erofs_pcluster, next);
owned = READ_ONCE(be.pcl->next);
- z_erofs_decompress_pcluster(&be, io->eio ? -EIO : 0);
+ err = z_erofs_decompress_pcluster(&be, err) ?: err;
if (z_erofs_is_inline_pcluster(be.pcl))
z_erofs_free_pcluster(be.pcl);
else
erofs_workgroup_put(&be.pcl->obj);
}
+ return err;
}
static void z_erofs_decompressqueue_work(struct work_struct *work)
@@ -1462,17 +1464,21 @@ static void z_erofs_fill_bio_vec(struct bio_vec *bvec,
folio_unlock(folio);
folio_put(folio);
out_allocfolio:
- page = erofs_allocpage(&f->pagepool, gfp | __GFP_NOFAIL);
+ page = erofs_allocpage(&f->pagepool, gfp);
spin_lock(&pcl->obj.lockref.lock);
if (unlikely(pcl->compressed_bvecs[nr].page != zbv.page)) {
- erofs_pagepool_add(&f->pagepool, page);
+ if (page)
+ erofs_pagepool_add(&f->pagepool, page);
spin_unlock(&pcl->obj.lockref.lock);
cond_resched();
goto repeat;
}
- bvec->bv_page = pcl->compressed_bvecs[nr].page = page;
- folio = page_folio(page);
+ pcl->compressed_bvecs[nr].page = page ? page : ERR_PTR(-ENOMEM);
spin_unlock(&pcl->obj.lockref.lock);
+ bvec->bv_page = page;
+ if (!page)
+ return;
+ folio = page_folio(page);
out_tocache:
if (!tocache || bs != PAGE_SIZE ||
filemap_add_folio(mc, folio, pcl->obj.index + nr, gfp)) {
@@ -1695,26 +1701,28 @@ static void z_erofs_submit_queue(struct z_erofs_decompress_frontend *f,
z_erofs_decompress_kickoff(q[JQ_SUBMIT], nr_bios);
}
-static void z_erofs_runqueue(struct z_erofs_decompress_frontend *f,
- bool force_fg, bool ra)
+static int z_erofs_runqueue(struct z_erofs_decompress_frontend *f,
+ unsigned int ra_folios)
{
struct z_erofs_decompressqueue io[NR_JOBQUEUES];
+ struct erofs_sb_info *sbi = EROFS_I_SB(f->inode);
+ bool force_fg = z_erofs_is_sync_decompress(sbi, ra_folios);
+ int err;
if (f->owned_head == Z_EROFS_PCLUSTER_TAIL)
- return;
- z_erofs_submit_queue(f, io, &force_fg, ra);
+ return 0;
+ z_erofs_submit_queue(f, io, &force_fg, !!ra_folios);
/* handle bypass queue (no i/o pclusters) immediately */
- z_erofs_decompress_queue(&io[JQ_BYPASS], &f->pagepool);
-
+ err = z_erofs_decompress_queue(&io[JQ_BYPASS], &f->pagepool);
if (!force_fg)
- return;
+ return err;
/* wait until all bios are completed */
wait_for_completion_io(&io[JQ_SUBMIT].u.done);
/* handle synchronous decompress queue in the caller context */
- z_erofs_decompress_queue(&io[JQ_SUBMIT], &f->pagepool);
+ return z_erofs_decompress_queue(&io[JQ_SUBMIT], &f->pagepool) ?: err;
}
/*
@@ -1776,7 +1784,6 @@ static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f,
static int z_erofs_read_folio(struct file *file, struct folio *folio)
{
struct inode *const inode = folio->mapping->host;
- struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
int err;
@@ -1788,9 +1795,8 @@ static int z_erofs_read_folio(struct file *file, struct folio *folio)
z_erofs_pcluster_readmore(&f, NULL, false);
z_erofs_pcluster_end(&f);
- /* if some compressed cluster ready, need submit them anyway */
- z_erofs_runqueue(&f, z_erofs_is_sync_decompress(sbi, 0), false);
-
+ /* if some pclusters are ready, need submit them anyway */
+ err = z_erofs_runqueue(&f, 0) ?: err;
if (err && err != -EINTR)
erofs_err(inode->i_sb, "read error %d @ %lu of nid %llu",
err, folio->index, EROFS_I(inode)->nid);
@@ -1803,7 +1809,6 @@ static int z_erofs_read_folio(struct file *file, struct folio *folio)
static void z_erofs_readahead(struct readahead_control *rac)
{
struct inode *const inode = rac->mapping->host;
- struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
struct folio *head = NULL, *folio;
unsigned int nr_folios;
@@ -1833,7 +1838,7 @@ static void z_erofs_readahead(struct readahead_control *rac)
z_erofs_pcluster_readmore(&f, rac, false);
z_erofs_pcluster_end(&f);
- z_erofs_runqueue(&f, z_erofs_is_sync_decompress(sbi, nr_folios), true);
+ (void)z_erofs_runqueue(&f, nr_folios);
erofs_put_metabuf(&f.map.buf);
erofs_release_pages(&f.pagepool);
}
--
2.43.5
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