btrfs: raid56: introduce new cached members for btrfs_raid_bio

The new members are all related to number of sectors, but the existing
number of pages members are kept as is:

- nr_sectors
  Total sectors of the full stripe including P/Q.

- stripe_nsectors
  The sectors of a single stripe.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 19d8a7b..1bc9858 100644 (file)
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -115,6 +115,9 @@ struct btrfs_raid_bio {
        /* How many pages there are for the full stripe including P/Q */
        u16 nr_pages;
 
+       /* How many sectors there are for the full stripe including P/Q */
+       u16 nr_sectors;
+
        /* Number of data stripes (no p/q) */
        u8 nr_data;
 
@@ -124,6 +127,9 @@ struct btrfs_raid_bio {
        /* How many pages there are for each stripe */
        u8 stripe_npages;
 
+       /* How many sectors there are for each stripe */
+       u8 stripe_nsectors;
+
        /* First bad stripe, -1 means no corruption */
        s8 faila;
 
@@ -172,7 +178,7 @@ struct btrfs_raid_bio {
        /* allocated with real_stripes-many pointers for finish_*() calls */
        void **finish_pointers;
 
-       /* allocated with stripe_npages-many bits for finish_*() calls */
+       /* Allocated with stripe_nsectors-many bits for finish_*() calls */
        unsigned long *finish_pbitmap;
 };
 
@@ -958,19 +964,22 @@ static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
        const unsigned int real_stripes = bioc->num_stripes - bioc->num_tgtdevs;
        const unsigned int stripe_npages = stripe_len >> PAGE_SHIFT;
        const unsigned int num_pages = stripe_npages * real_stripes;
+       const unsigned int stripe_nsectors = stripe_len >> fs_info->sectorsize_bits;
+       const unsigned int num_sectors = stripe_nsectors * real_stripes;
        struct btrfs_raid_bio *rbio;
        int nr_data = 0;
        void *p;
 
        ASSERT(IS_ALIGNED(stripe_len, PAGE_SIZE));
+       /* PAGE_SIZE must also be aligned to sectorsize for subpage support */
+       ASSERT(IS_ALIGNED(PAGE_SIZE, fs_info->sectorsize));
 
        rbio = kzalloc(sizeof(*rbio) +
                       sizeof(*rbio->stripe_pages) * num_pages +
                       sizeof(*rbio->bio_pages) * num_pages +
                       sizeof(*rbio->finish_pointers) * real_stripes +
-                      sizeof(*rbio->dbitmap) * BITS_TO_LONGS(stripe_npages) +
-                      sizeof(*rbio->finish_pbitmap) *
-                               BITS_TO_LONGS(stripe_npages),
+                      sizeof(*rbio->dbitmap) * BITS_TO_LONGS(stripe_nsectors) +
+                      sizeof(*rbio->finish_pbitmap) * BITS_TO_LONGS(stripe_nsectors),
                       GFP_NOFS);
        if (!rbio)
                return ERR_PTR(-ENOMEM);
@@ -983,8 +992,10 @@ static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
        rbio->bioc = bioc;
        rbio->stripe_len = stripe_len;
        rbio->nr_pages = num_pages;
+       rbio->nr_sectors = num_sectors;
        rbio->real_stripes = real_stripes;
        rbio->stripe_npages = stripe_npages;
+       rbio->stripe_nsectors = stripe_nsectors;
        rbio->faila = -1;
        rbio->failb = -1;
        refcount_set(&rbio->refs, 1);
@@ -1003,8 +1014,8 @@ static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
        CONSUME_ALLOC(rbio->stripe_pages, num_pages);
        CONSUME_ALLOC(rbio->bio_pages, num_pages);
        CONSUME_ALLOC(rbio->finish_pointers, real_stripes);
-       CONSUME_ALLOC(rbio->dbitmap, BITS_TO_LONGS(stripe_npages));
-       CONSUME_ALLOC(rbio->finish_pbitmap, BITS_TO_LONGS(stripe_npages));
+       CONSUME_ALLOC(rbio->dbitmap, BITS_TO_LONGS(stripe_nsectors));
+       CONSUME_ALLOC(rbio->finish_pbitmap, BITS_TO_LONGS(stripe_nsectors));
 #undef  CONSUME_ALLOC
 
        if (bioc->map_type & BTRFS_BLOCK_GROUP_RAID5)