From: Michal Rostecki <mroste...@suse.com>

Before this change, the btrfs_get_io_geometry() function was calling
btrfs_get_chunk_map() to get the extent mapping, necessary for
calculating the I/O geometry. It was using that extent mapping only
internally and freeing the pointer after its execution.

That resulted in calling btrfs_get_chunk_map() de facto twice by the
__btrfs_map_block() function. It was calling btrfs_get_io_geometry()
first and then calling btrfs_get_chunk_map() directly to get the extent
mapping, used by the rest of the function.

This change fixes that by passing the extent mapping to the
btrfs_get_io_geometry() function as an argument.

v2:
When btrfs_get_chunk_map() returns an error in btrfs_submit_direct():
- Use errno_to_blk_status(PTR_ERR(em)) as the status
- Set em to NULL

Signed-off-by: Michal Rostecki <mroste...@suse.com>
---
 fs/btrfs/inode.c   | 38 +++++++++++++++++++++++++++++---------
 fs/btrfs/volumes.c | 39 ++++++++++++++++-----------------------
 fs/btrfs/volumes.h |  5 +++--
 3 files changed, 48 insertions(+), 34 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 0dbe1aaa0b71..e2ee3a9c1140 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2183,9 +2183,10 @@ int btrfs_bio_fits_in_stripe(struct page *page, size_t 
size, struct bio *bio,
        struct inode *inode = page->mapping->host;
        struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
        u64 logical = bio->bi_iter.bi_sector << 9;
+       struct extent_map *em;
        u64 length = 0;
        u64 map_length;
-       int ret;
+       int ret = 0;
        struct btrfs_io_geometry geom;
 
        if (bio_flags & EXTENT_BIO_COMPRESSED)
@@ -2193,14 +2194,21 @@ int btrfs_bio_fits_in_stripe(struct page *page, size_t 
size, struct bio *bio,
 
        length = bio->bi_iter.bi_size;
        map_length = length;
-       ret = btrfs_get_io_geometry(fs_info, btrfs_op(bio), logical, map_length,
-                                   &geom);
+       em = btrfs_get_chunk_map(fs_info, logical, map_length);
+       if (IS_ERR(em))
+               return PTR_ERR(em);
+       ret = btrfs_get_io_geometry(fs_info, em, btrfs_op(bio), logical,
+                                   map_length, &geom);
        if (ret < 0)
-               return ret;
+               goto out;
 
-       if (geom.len < length + size)
-               return 1;
-       return 0;
+       if (geom.len < length + size) {
+               ret = 1;
+               goto out;
+       }
+out:
+       free_extent_map(em);
+       return ret;
 }
 
 /*
@@ -7941,10 +7949,12 @@ static blk_qc_t btrfs_submit_direct(struct inode 
*inode, struct iomap *iomap,
        u64 submit_len;
        int clone_offset = 0;
        int clone_len;
+       int logical;
        int ret;
        blk_status_t status;
        struct btrfs_io_geometry geom;
        struct btrfs_dio_data *dio_data = iomap->private;
+       struct extent_map *em;
 
        dip = btrfs_create_dio_private(dio_bio, inode, file_offset);
        if (!dip) {
@@ -7970,11 +7980,18 @@ static blk_qc_t btrfs_submit_direct(struct inode 
*inode, struct iomap *iomap,
        }
 
        start_sector = dio_bio->bi_iter.bi_sector;
+       logical = start_sector << 9;
        submit_len = dio_bio->bi_iter.bi_size;
 
        do {
-               ret = btrfs_get_io_geometry(fs_info, btrfs_op(dio_bio),
-                                           start_sector << 9, submit_len,
+               em = btrfs_get_chunk_map(fs_info, logical, submit_len);
+               if (IS_ERR(em)) {
+                       status = errno_to_blk_status(PTR_ERR(em));
+                       em = NULL;
+                       goto out_err;
+               }
+               ret = btrfs_get_io_geometry(fs_info, em, btrfs_op(dio_bio),
+                                           logical, submit_len,
                                            &geom);
                if (ret) {
                        status = errno_to_blk_status(ret);
@@ -8030,12 +8047,15 @@ static blk_qc_t btrfs_submit_direct(struct inode 
*inode, struct iomap *iomap,
                clone_offset += clone_len;
                start_sector += clone_len >> 9;
                file_offset += clone_len;
+
+               free_extent_map(em);
        } while (submit_len > 0);
        return BLK_QC_T_NONE;
 
 out_err:
        dip->dio_bio->bi_status = status;
        btrfs_dio_private_put(dip);
+       free_extent_map(em);
        return BLK_QC_T_NONE;
 }
 
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index a8ec8539cd8d..4c753b17c0a2 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5940,23 +5940,24 @@ static bool need_full_stripe(enum btrfs_map_op op)
 }
 
 /*
- * btrfs_get_io_geometry - calculates the geomery of a particular (address, 
len)
+ * btrfs_get_io_geometry - calculates the geometry of a particular (address, 
len)
  *                    tuple. This information is used to calculate how big a
  *                    particular bio can get before it straddles a stripe.
  *
- * @fs_info - the filesystem
- * @logical - address that we want to figure out the geometry of
- * @len            - the length of IO we are going to perform, starting at 
@logical
- * @op      - type of operation - write or read
- * @io_geom - pointer used to return values
+ * @fs_info: the filesystem
+ * @em:      mapping containing the logical extent
+ * @op:      type of operation - write or read
+ * @logical: address that we want to figure out the geometry of
+ * @len:     the length of IO we are going to perform, starting at @logical
+ * @io_geom: pointer used to return values
  *
  * Returns < 0 in case a chunk for the given logical address cannot be found,
  * usually shouldn't happen unless @logical is corrupted, 0 otherwise.
  */
-int btrfs_get_io_geometry(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
-                       u64 logical, u64 len, struct btrfs_io_geometry *io_geom)
+int btrfs_get_io_geometry(struct btrfs_fs_info *fs_info, struct extent_map *em,
+                         enum btrfs_map_op op, u64 logical, u64 len,
+                         struct btrfs_io_geometry *io_geom)
 {
-       struct extent_map *em;
        struct map_lookup *map;
        u64 offset;
        u64 stripe_offset;
@@ -5964,14 +5965,9 @@ int btrfs_get_io_geometry(struct btrfs_fs_info *fs_info, 
enum btrfs_map_op op,
        u64 stripe_len;
        u64 raid56_full_stripe_start = (u64)-1;
        int data_stripes;
-       int ret = 0;
 
        ASSERT(op != BTRFS_MAP_DISCARD);
 
-       em = btrfs_get_chunk_map(fs_info, logical, len);
-       if (IS_ERR(em))
-               return PTR_ERR(em);
-
        map = em->map_lookup;
        /* Offset of this logical address in the chunk */
        offset = logical - em->start;
@@ -5985,8 +5981,7 @@ int btrfs_get_io_geometry(struct btrfs_fs_info *fs_info, 
enum btrfs_map_op op,
                btrfs_crit(fs_info,
 "stripe math has gone wrong, stripe_offset=%llu offset=%llu start=%llu 
logical=%llu stripe_len=%llu",
                        stripe_offset, offset, em->start, logical, stripe_len);
-               ret = -EINVAL;
-               goto out;
+               return -EINVAL;
        }
 
        /* stripe_offset is the offset of this block in its stripe */
@@ -6033,10 +6028,7 @@ int btrfs_get_io_geometry(struct btrfs_fs_info *fs_info, 
enum btrfs_map_op op,
        io_geom->stripe_offset = stripe_offset;
        io_geom->raid56_stripe_offset = raid56_full_stripe_start;
 
-out:
-       /* once for us */
-       free_extent_map(em);
-       return ret;
+       return 0;
 }
 
 static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
@@ -6069,12 +6061,13 @@ static int __btrfs_map_block(struct btrfs_fs_info 
*fs_info,
        ASSERT(bbio_ret);
        ASSERT(op != BTRFS_MAP_DISCARD);
 
-       ret = btrfs_get_io_geometry(fs_info, op, logical, *length, &geom);
+       em = btrfs_get_chunk_map(fs_info, logical, *length);
+       ASSERT(!IS_ERR(em));
+
+       ret = btrfs_get_io_geometry(fs_info, em, op, logical, *length, &geom);
        if (ret < 0)
                return ret;
 
-       em = btrfs_get_chunk_map(fs_info, logical, *length);
-       ASSERT(!IS_ERR(em));
        map = em->map_lookup;
 
        *length = geom.len;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index c43663d9c22e..04e2b26823c2 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -440,8 +440,9 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum 
btrfs_map_op op,
 int btrfs_map_sblock(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
                     u64 logical, u64 *length,
                     struct btrfs_bio **bbio_ret);
-int btrfs_get_io_geometry(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
-               u64 logical, u64 len, struct btrfs_io_geometry *io_geom);
+int btrfs_get_io_geometry(struct btrfs_fs_info *fs_info, struct extent_map 
*map,
+                         enum btrfs_map_op op, u64 logical, u64 len,
+                         struct btrfs_io_geometry *io_geom);
 int btrfs_read_sys_array(struct btrfs_fs_info *fs_info);
 int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info);
 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans, u64 type);
-- 
2.30.0

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