@@ -443,9 +443,27 @@ int btrfs_check_sector_csum(struct btrfs_fs_info *fs_info, struct page *page,
u32 pgoff, u8 *csum, const u8 * const csum_expected);
bool btrfs_data_csum_ok(struct btrfs_bio *bbio, struct btrfs_device *dev,
u32 bio_offset, struct bio_vec *bv);
+
+/*
+ * A more access-friendly representation of btrfs_file_extent_item.
+ *
+ * Unused members are excluded.
+ */
+struct btrfs_file_extent {
+ u64 disk_bytenr;
+ u64 disk_num_bytes;
+
+ u64 num_bytes;
+ u64 ram_bytes;
+ u64 offset;
+
+ u8 compression;
+};
+
noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
u64 *orig_start, u64 *orig_block_len,
- u64 *ram_bytes, bool nowait, bool strict);
+ u64 *ram_bytes, struct btrfs_file_extent *file_extent,
+ bool nowait, bool strict);
void btrfs_del_delalloc_inode(struct btrfs_inode *inode);
struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry);
@@ -1104,7 +1104,7 @@ int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos,
&cached_state);
}
ret = can_nocow_extent(&inode->vfs_inode, lockstart, &num_bytes,
- NULL, NULL, NULL, nowait, false);
+ NULL, NULL, NULL, NULL, nowait, false);
if (ret <= 0)
btrfs_drew_write_unlock(&root->snapshot_lock);
else
@@ -1830,6 +1830,9 @@ struct can_nocow_file_extent_args {
u64 extent_offset;
/* Number of bytes that can be written to in NOCOW mode. */
u64 num_bytes;
+
+ /* The expected file extent for the NOCOW write. */
+ struct btrfs_file_extent file_extent;
};
/*
@@ -1894,6 +1897,12 @@ static int can_nocow_file_extent(struct btrfs_path *path,
extent_end = btrfs_file_extent_end(path);
+ args->file_extent.disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+ args->file_extent.disk_num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
+ args->file_extent.ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
+ args->file_extent.offset = btrfs_file_extent_offset(leaf, fi);
+ args->file_extent.compression = btrfs_file_extent_compression(leaf, fi);
+
/*
* The following checks can be expensive, as they need to take other
* locks and do btree or rbtree searches, so release the path to avoid
@@ -1928,6 +1937,9 @@ static int can_nocow_file_extent(struct btrfs_path *path,
args->disk_bytenr += args->start - key->offset;
args->num_bytes = min(args->end + 1, extent_end) - args->start;
+ args->file_extent.num_bytes = args->num_bytes;
+ args->file_extent.offset += args->start - key->offset;
+
/*
* Force COW if csums exist in the range. This ensures that csums for a
* given extent are either valid or do not exist.
@@ -7058,7 +7070,8 @@ static bool btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
*/
noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
u64 *orig_start, u64 *orig_block_len,
- u64 *ram_bytes, bool nowait, bool strict)
+ u64 *ram_bytes, struct btrfs_file_extent *file_extent,
+ bool nowait, bool strict)
{
struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
struct can_nocow_file_extent_args nocow_args = { 0 };
@@ -7147,6 +7160,9 @@ noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
*orig_start = key.offset - nocow_args.extent_offset;
if (orig_block_len)
*orig_block_len = nocow_args.disk_num_bytes;
+ if (file_extent)
+ memcpy(file_extent, &nocow_args.file_extent,
+ sizeof(struct btrfs_file_extent));
*len = nocow_args.num_bytes;
ret = 1;
@@ -7366,7 +7382,7 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map,
block_start = em->block_start + (start - em->start);
if (can_nocow_extent(inode, start, &len, &orig_start,
- &orig_block_len, &ram_bytes, false, false) == 1) {
+ &orig_block_len, &ram_bytes, NULL, false, false) == 1) {
bg = btrfs_inc_nocow_writers(fs_info, block_start);
if (bg)
can_nocow = true;
@@ -10617,7 +10633,7 @@ static int btrfs_swap_activate(struct swap_info_struct *sis, struct file *file,
free_extent_map(em);
em = NULL;
- ret = can_nocow_extent(inode, start, &len, NULL, NULL, NULL, false, true);
+ ret = can_nocow_extent(inode, start, &len, NULL, NULL, NULL, NULL, false, true);
if (ret < 0) {
goto out;
} else if (ret) {
Currently function can_nocow_extent() only returns members needed for extent_map. However since we will soon change the extent_map structure to be more like btrfs_file_extent_item, we want to expose the expected file extent caused by the NOCOW write for future usage. This would introduce a new structure, btrfs_file_extent, to be a more memory-access-friendly representation of btrfs_file_extent_item. And use that structure to expose the expected file extent caused by the NOCOW write. For now there is no user of the new structure yet. Signed-off-by: Qu Wenruo <wqu@suse.com> --- fs/btrfs/btrfs_inode.h | 20 +++++++++++++++++++- fs/btrfs/file.c | 2 +- fs/btrfs/inode.c | 22 +++++++++++++++++++--- 3 files changed, 39 insertions(+), 5 deletions(-)