From: Gao Xiang <hsiang...@redhat.com>
Martin reported an issue that directory read could be hung on the
latest -rc kernel with some certain image. The root cause is that
commit baa2c7c97153 ("block: set .bi_max_vecs as actual allocated
vector number") changes .bi_max_vecs behavior. bio->bi_max_vecs
is set as actual allocated vector number rather than the requested
number now.
Let's avoid using .bi_max_vecs completely instead.
Reported-by: Martin DEVERA <de...@eaxlabs.cz>
Signed-off-by: Gao Xiang <hsiang...@redhat.com>
---
change since v1:
- since bio->bi_max_vecs doesn't record extent blocks anymore,
introduce a remaining extent block to avoid extent excess.
fs/erofs/data.c | 28 +++++++++++-----------------
1 file changed, 11 insertions(+), 17 deletions(-)
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index f88851c5c250..1249e74b3bf0 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -129,6 +129,7 @@ static inline struct bio *erofs_read_raw_page(struct bio
*bio,
struct page *page,
erofs_off_t *last_block,
unsigned int nblocks,
+ unsigned int *eblks,
bool ra)
{
struct inode *const inode = mapping->host;
@@ -145,8 +146,7 @@ static inline struct bio *erofs_read_raw_page(struct bio
*bio,
/* note that for readpage case, bio also equals to NULL */
if (bio &&
- /* not continuous */
- *last_block + 1 != current_block) {
+ (*last_block + 1 != current_block || !*eblks)) {
submit_bio_retry:
submit_bio(bio);
bio = NULL;
@@ -216,7 +216,8 @@ static inline struct bio *erofs_read_raw_page(struct bio
*bio,
if (nblocks > DIV_ROUND_UP(map.m_plen, PAGE_SIZE))
nblocks = DIV_ROUND_UP(map.m_plen, PAGE_SIZE);
- bio = bio_alloc(GFP_NOIO, bio_max_segs(nblocks));
+ *eblks = bio_max_segs(nblocks);
+ bio = bio_alloc(GFP_NOIO, *eblks);
bio->bi_end_io = erofs_readendio;
bio_set_dev(bio, sb->s_bdev);
@@ -229,16 +230,8 @@ static inline struct bio *erofs_read_raw_page(struct bio
*bio,
/* out of the extent or bio is full */
if (err < PAGE_SIZE)
goto submit_bio_retry;
-
+ --*eblks;
*last_block = current_block;
-
- /* shift in advance in case of it followed by too many gaps */
- if (bio->bi_iter.bi_size >= bio->bi_max_vecs * PAGE_SIZE) {
- /* err should reassign to 0 after submitting */
- err = 0;
- goto submit_bio_out;
- }
-
return bio;
err_out:
@@ -252,7 +245,6 @@ static inline struct bio *erofs_read_raw_page(struct bio
*bio,
/* if updated manually, continuous pages has a gap */
if (bio)
-submit_bio_out:
submit_bio(bio);
return err ? ERR_PTR(err) : NULL;
}
@@ -264,23 +256,26 @@ static inline struct bio *erofs_read_raw_page(struct bio
*bio,
static int erofs_raw_access_readpage(struct file *file, struct page *page)
{
erofs_off_t last_block;
+ unsigned int eblks;
struct bio *bio;
trace_erofs_readpage(page, true);
bio = erofs_read_raw_page(NULL, page->mapping,
- page, &last_block, 1, false);
+ page, &last_block, 1, &eblks, false);
if (IS_ERR(bio))
return PTR_ERR(bio);
- DBG_BUGON(bio); /* since we have only one bio -- must be NULL */
+ if (bio)
+ submit_bio(bio);
return 0;
}
static void erofs_raw_access_readahead(struct readahead_control *rac)
{
erofs_off_t last_block;
+ unsigned int eblks;
struct bio *bio = NULL;
struct page *page;
@@ -291,7 +286,7 @@ static void erofs_raw_access_readahead(struct
readahead_control *rac)
prefetchw(&page->flags);
bio = erofs_read_raw_page(bio, rac->mapping, page, &last_block,
- readahead_count(rac), true);
+ readahead_count(rac), &eblks, true);
/* all the page errors are ignored when readahead */
if (IS_ERR(bio)) {
@@ -305,7 +300,6 @@ static void erofs_raw_access_readahead(struct
readahead_control *rac)
put_page(page);
}
- /* the rare case (end in gaps) */
if (bio)
submit_bio(bio);
}
--
2.20.1
