From: Andreas Gruenbacher agruenba@redhat.com
commit eed0f953b90e86e765197a1dad06bb48aedc27fe upstream.
On filesystems with a block size smaller than the page size, gfs2_find_jhead can split a page across two bios (for example, when blocks are not allocated consecutively). When that happens, the first bio that completes will unlock the page in its bi_end_io handler even though the page hasn't been read completely yet. Fix that by using a chained bio for the rest of the page.
While at it, clean up the sector calculation logic in gfs2_log_alloc_bio. In gfs2_find_jhead, simplify the disk block and offset calculation logic and fix a variable name.
Fixes: f4686c26ecc3 ("gfs2: read journal in large chunks") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by: Andreas Gruenbacher agruenba@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/gfs2/lops.c | 68 ++++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 44 insertions(+), 24 deletions(-)
--- a/fs/gfs2/lops.c +++ b/fs/gfs2/lops.c @@ -264,7 +264,7 @@ static struct bio *gfs2_log_alloc_bio(st struct super_block *sb = sdp->sd_vfs; struct bio *bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
- bio->bi_iter.bi_sector = blkno * (sb->s_blocksize >> 9); + bio->bi_iter.bi_sector = blkno << (sb->s_blocksize_bits - 9); bio_set_dev(bio, sb->s_bdev); bio->bi_end_io = end_io; bio->bi_private = sdp; @@ -471,6 +471,20 @@ static void gfs2_jhead_process_page(stru put_page(page); /* Once more for find_or_create_page */ }
+static struct bio *gfs2_chain_bio(struct bio *prev, unsigned int nr_iovecs) +{ + struct bio *new; + + new = bio_alloc(GFP_NOIO, nr_iovecs); + bio_copy_dev(new, prev); + new->bi_iter.bi_sector = bio_end_sector(prev); + new->bi_opf = prev->bi_opf; + new->bi_write_hint = prev->bi_write_hint; + bio_chain(new, prev); + submit_bio(prev); + return new; +} + /** * gfs2_find_jhead - find the head of a log * @jd: The journal descriptor @@ -487,15 +501,15 @@ int gfs2_find_jhead(struct gfs2_jdesc *j struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode); struct address_space *mapping = jd->jd_inode->i_mapping; unsigned int block = 0, blocks_submitted = 0, blocks_read = 0; - unsigned int bsize = sdp->sd_sb.sb_bsize; + unsigned int bsize = sdp->sd_sb.sb_bsize, off; unsigned int bsize_shift = sdp->sd_sb.sb_bsize_shift; unsigned int shift = PAGE_SHIFT - bsize_shift; - unsigned int readhead_blocks = BIO_MAX_PAGES << shift; + unsigned int readahead_blocks = BIO_MAX_PAGES << shift; struct gfs2_journal_extent *je; int sz, ret = 0; struct bio *bio = NULL; struct page *page = NULL; - bool done = false; + bool bio_chained = false, done = false; errseq_t since;
memset(head, 0, sizeof(*head)); @@ -504,9 +518,9 @@ int gfs2_find_jhead(struct gfs2_jdesc *j
since = filemap_sample_wb_err(mapping); list_for_each_entry(je, &jd->extent_list, list) { - for (; block < je->lblock + je->blocks; block++) { - u64 dblock; + u64 dblock = je->dblock;
+ for (; block < je->lblock + je->blocks; block++, dblock++) { if (!page) { page = find_or_create_page(mapping, block >> shift, GFP_NOFS); @@ -515,35 +529,41 @@ int gfs2_find_jhead(struct gfs2_jdesc *j done = true; goto out; } + off = 0; }
- if (bio) { - unsigned int off; - - off = (block << bsize_shift) & ~PAGE_MASK; + if (!bio || (bio_chained && !off)) { + /* start new bio */ + } else { sz = bio_add_page(bio, page, bsize, off); - if (sz == bsize) { /* block added */ - if (off + bsize == PAGE_SIZE) { - page = NULL; - goto page_added; - } - continue; + if (sz == bsize) + goto block_added; + if (off) { + unsigned int blocks = + (PAGE_SIZE - off) >> bsize_shift; + + bio = gfs2_chain_bio(bio, blocks); + bio_chained = true; + goto add_block_to_new_bio; } + } + + if (bio) { blocks_submitted = block + 1; submit_bio(bio); - bio = NULL; }
- dblock = je->dblock + (block - je->lblock); bio = gfs2_log_alloc_bio(sdp, dblock, gfs2_end_log_read); bio->bi_opf = REQ_OP_READ; - sz = bio_add_page(bio, page, bsize, 0); - gfs2_assert_warn(sdp, sz == bsize); - if (bsize == PAGE_SIZE) + bio_chained = false; +add_block_to_new_bio: + sz = bio_add_page(bio, page, bsize, off); + BUG_ON(sz != bsize); +block_added: + off += bsize; + if (off == PAGE_SIZE) page = NULL; - -page_added: - if (blocks_submitted < blocks_read + readhead_blocks) { + if (blocks_submitted < blocks_read + readahead_blocks) { /* Keep at least one bio in flight */ continue; }