bio_check_eod() should check partiton size not the whole disk if
bio->bi_partno is non-zero.

Based on an earlier patch from Jiufei Xue.

Fixes: 74d46992e0d9 ("block: replace bi_bdev with a gendisk pointer and 
partitions index")
Reported-by: Jiufei Xue <jiufei....@linux.alibaba.com>
Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 block/blk-core.c | 76 ++++++++++++++++++++++----------------------------------
 1 file changed, 30 insertions(+), 46 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 3ba4326a63b5..ba07f970e011 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2009,7 +2009,7 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, 
struct bio *bio)
        return BLK_QC_T_NONE;
 }
 
-static void handle_bad_sector(struct bio *bio)
+static void handle_bad_sector(struct bio *bio, sector_t maxsector)
 {
        char b[BDEVNAME_SIZE];
 
@@ -2017,7 +2017,7 @@ static void handle_bad_sector(struct bio *bio)
        printk(KERN_INFO "%s: rw=%d, want=%Lu, limit=%Lu\n",
                        bio_devname(bio, b), bio->bi_opf,
                        (unsigned long long)bio_end_sector(bio),
-                       (long long)get_capacity(bio->bi_disk));
+                       (long long)maxsector);
 }
 
 #ifdef CONFIG_FAIL_MAKE_REQUEST
@@ -2060,57 +2060,47 @@ static inline bool should_fail_request(struct hd_struct 
*part,
  */
 static inline int blk_partition_remap(struct bio *bio)
 {
-       struct hd_struct *p;
-       int ret = 0;
+       sector_t maxsector = get_capacity(bio->bi_disk);
+       int nr_sectors = bio_sectors(bio);
 
        /*
         * Zone reset does not include bi_size so bio_sectors() is always 0.
         * Include a test for the reset op code and perform the remap if needed.
         */
-       if (!bio->bi_partno ||
-           (!bio_sectors(bio) && bio_op(bio) != REQ_OP_ZONE_RESET))
+       if (!nr_sectors && bio_op(bio) != REQ_OP_ZONE_RESET)
                return 0;
 
-       rcu_read_lock();
-       p = __disk_get_part(bio->bi_disk, bio->bi_partno);
-       if (likely(p && !should_fail_request(p, bio->bi_iter.bi_size))) {
+       if (bio->bi_partno) {
+               struct hd_struct *p;
+
+               rcu_read_lock();
+               p = __disk_get_part(bio->bi_disk, bio->bi_partno);
+               if (unlikely(!p ||
+                            should_fail_request(p, bio->bi_iter.bi_size))) {
+                       rcu_read_unlock();
+                       pr_info("%s: failing request for partition %d\n",
+                               __func__, bio->bi_partno);
+                       return -EIO;
+               }
+
                bio->bi_iter.bi_sector += p->start_sect;
                bio->bi_partno = 0;
                trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p),
                                bio->bi_iter.bi_sector - p->start_sect);
-       } else {
-               printk("%s: fail for partition %d\n", __func__, bio->bi_partno);
-               ret = -EIO;
+               maxsector = part_nr_sects_read(p);
+               rcu_read_unlock();
        }
-       rcu_read_unlock();
 
-       return ret;
-}
-
-/*
- * Check whether this bio extends beyond the end of the device.
- */
-static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
-{
-       sector_t maxsector;
-
-       if (!nr_sectors)
-               return 0;
-
-       /* Test device or partition size, when known. */
-       maxsector = get_capacity(bio->bi_disk);
-       if (maxsector) {
-               sector_t sector = bio->bi_iter.bi_sector;
-
-               if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
-                       /*
-                        * This may well happen - the kernel calls bread()
-                        * without checking the size of the device, e.g., when
-                        * mounting a device.
-                        */
-                       handle_bad_sector(bio);
-                       return 1;
-               }
+       /*
+        * Check whether this bio extends beyond the end of the device or
+        * partition.  This may well happen - the kernel calls bread() without
+        * checking the size of the device, e.g., when mounting a file system.
+        */
+       if (nr_sectors && maxsector &&
+           (nr_sectors > maxsector ||
+            bio->bi_iter.bi_sector > maxsector - nr_sectors)) {
+               handle_bad_sector(bio, maxsector);
+               return -EIO;
        }
 
        return 0;
@@ -2126,9 +2116,6 @@ generic_make_request_checks(struct bio *bio)
 
        might_sleep();
 
-       if (bio_check_eod(bio, nr_sectors))
-               goto end_io;
-
        q = bio->bi_disk->queue;
        if (unlikely(!q)) {
                printk(KERN_ERR
@@ -2152,9 +2139,6 @@ generic_make_request_checks(struct bio *bio)
        if (blk_partition_remap(bio))
                goto end_io;
 
-       if (bio_check_eod(bio, nr_sectors))
-               goto end_io;
-
        /*
         * Filter flush bio's early so that make_request based
         * drivers without flush support don't have to worry
-- 
2.14.2

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