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Date: Wed, 27 Jan 2021 14:57:27 +0100
From: Michal Rostecki <mrostecki@...e.de>
To: Chris Mason <clm@...com>, Josef Bacik <josef@...icpanda.com>,
David Sterba <dsterba@...e.com>, linux-btrfs@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Michal Rostecki <mrostecki@...e.com>
Subject: [PATCH v2] btrfs: Avoid calling btrfs_get_chunk_map() twice
From: Michal Rostecki <mrostecki@...e.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 <mrostecki@...e.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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