Add basic nocow compressed write into preallocated range support in
mkfs and headers.
Now we can use mkfs to create a btrfs which supports nocow compressed
prealloc write.
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
---
ctree.h | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
mkfs.c | 2 ++
2 files changed, 70 insertions(+), 1 deletion(-)
diff --git a/ctree.h b/ctree.h
index fa73c4a..ab87133 100644
--- a/ctree.h
+++ b/ctree.h
@@ -473,6 +473,7 @@ struct btrfs_super_block {
#define BTRFS_FEATURE_INCOMPAT_RAID56 (1ULL << 7)
#define BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA (1ULL << 8)
#define BTRFS_FEATURE_INCOMPAT_NO_HOLES (1ULL << 9)
+#define BTRFS_FEATURE_INCOMPAT_COMPPREALLOC (1ULL << 10)
#define BTRFS_FEATURE_COMPAT_SUPP 0ULL
@@ -486,7 +487,8 @@ struct btrfs_super_block {
BTRFS_FEATURE_INCOMPAT_RAID56 | \
BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS | \
BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA | \
- BTRFS_FEATURE_INCOMPAT_NO_HOLES)
+ BTRFS_FEATURE_INCOMPAT_NO_HOLES | \
+ BTRFS_FEATURE_INCOMPAT_COMPPREALLOC)
/*
* A leaf is full of items. offset and size tell us where to find
@@ -825,6 +827,18 @@ struct btrfs_file_extent_item {
} __attribute__ ((__packed__));
+struct __compprealloc_data {
+ /* extent offset where we read data from disk. */
+ __le64 data_offset;
+ /* extent len that we need read into memory. */
+ __le64 data_len;
+
+} __attribute__ ((__packed__));
+
+#define BTRFS_FILE_EXTENT_SIZE_NORMAL (sizeof(struct btrfs_file_extent_item))
+#define BTRFS_FILE_EXTENT_SIZE_MAX (sizeof(struct btrfs_file_extent_item) + \
+ sizeof(struct __compprealloc_data))
+
struct btrfs_csum_item {
u8 csum;
} __attribute__ ((__packed__));
@@ -2146,6 +2160,59 @@ static inline int btrfs_fs_incompat(struct btrfs_fs_info
*fs_info, u64 flag)
return !!(btrfs_super_incompat_flags(disk_super) & flag);
}
+/* struct __compprealloc_data, don't use them directly!!! */
+BTRFS_SETGET_FUNCS(__compprealloc_data_offset, struct __compprealloc_data,
+ data_offset, 64);
+BTRFS_SETGET_FUNCS(__compprealloc_data_len, struct __compprealloc_data,
+ data_len, 64);
+
+/*
+ * functions for appended data after a original structure
+ * unlike kernel part, eb has no member fs_info, so caller should check
+ * the incompatible flag manually
+ */
+#define BTRFS_SETGET_APPEND_FUNCS(name, type, new_type, func, bits, \
+ flag, fallback) \
+static inline u##bits btrfs_##name(struct extent_buffer *eb, \
+ int slot, type *s) \
+{ \
+ if (btrfs_item_size_nr(eb, slot) > sizeof(*s)) \
+ return btrfs_##func(eb, (new_type *)(s + 1)); \
+ return fallback(eb, s); \
+} \
+static inline void btrfs_set_##name(struct extent_buffer *eb, \
+ int slot, type *s, u##bits val) \
+{ \
+ if (btrfs_item_size_nr(eb, slot) > sizeof(*s)) \
+ btrfs_set_##func(eb, (new_type *)(s + 1), val); \
+} \
+
+/* appended data for btrfs_file_extent_item */
+static inline u64
+data_offset_fallback(struct extent_buffer *eb,
+ struct btrfs_file_extent_item *fi)
+{
+ return 0;
+}
+BTRFS_SETGET_APPEND_FUNCS(ondemand_file_extent_data_offset,
+ struct btrfs_file_extent_item,
+ struct __compprealloc_data,
+ __compprealloc_data_offset,
+ 64, COMPPREALLOC, data_offset_fallback);
+
+static inline u64
+data_len_fallback(struct extent_buffer *eb,
+ struct btrfs_file_extent_item *fi)
+{
+ return btrfs_file_extent_disk_num_bytes(eb, fi);
+}
+BTRFS_SETGET_APPEND_FUNCS(ondemand_file_extent_data_len,
+ struct btrfs_file_extent_item,
+ struct __compprealloc_data,
+ __compprealloc_data_len,
+ 64, COMPPREALLOC, data_len_fallback);
+
+
/* helper function to cast into the data area of the leaf. */
#define btrfs_item_ptr(leaf, slot, type) \
((type *)(btrfs_leaf_data(leaf) + \
diff --git a/mkfs.c b/mkfs.c
index 9de61e1..da1e586 100644
--- a/mkfs.c
+++ b/mkfs.c
@@ -1163,6 +1163,8 @@ static const struct btrfs_fs_feature {
"reduced-size metadata extent refs" },
{ "no-holes", BTRFS_FEATURE_INCOMPAT_NO_HOLES,
"no explicit hole extents for files" },
+ { "compressed-prealloc", BTRFS_FEATURE_INCOMPAT_COMPPREALLOC,
+ "alloc nocow compressed write into preallocated space"},
/* Keep this one last */
{ "list-all", BTRFS_FEATURE_LIST_ALL, NULL }
};
--
2.1.0
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