[BUG]
There is a long existing bug in the last parameter of
btrfs_add_ordered_extent(), in commit 771ed689d2cd ("Btrfs: Optimize
compressed writeback and reads") back to 2008.
In that ancient commit btrfs_add_ordered_extent() expects the @type
parameter to be one of the following:
- BTRFS_ORDERED_REGULAR
- BTRFS_ORDERED_NOCOW
- BTRFS_ORDERED_PREALLOC
- BTRFS_ORDERED_COMPRESSED
But we pass 0 in cow_file_range(), which means BTRFS_ORDERED_IO_DONE.
Ironically extra check in __btrfs_add_ordered_extent() won't set the bit
if we're seeing (type == IO_DONE || type == IO_COMPLETE), and avoid any
obvious bug.
But this still leads to regular COW ordered extent having no bit to
indicate its type in various trace events, rendering REGULAR bit
useless.
[FIX]
This patch will change the following aspects to avoid such problem:
- Reorder btrfs_ordered_extent::flags
Now the type bits go first (REGULAR/NOCOW/PREALLCO/COMPRESSED), then
DIRECT bit, finally extra status bits like IO_DONE/COMPLETE/IOERR.
- Add extra ASSERT() for btrfs_add_ordered_extent_*()
- Remove @type parameter for btrfs_add_ordered_extent_compress()
As the only valid @type here is BTRFS_ORDERED_COMPRESSED.
- Remove the unnecessary special check for IO_DONE/COMPLETE in
__btrfs_add_ordered_extent()
This is just to make the code work, with extra ASSERT(), there are
limited values can be passed in.
Signed-off-by: Qu Wenruo <w...@suse.com>
---
fs/btrfs/inode.c | 4 ++--
fs/btrfs/ordered-data.c | 18 +++++++++++++-----
fs/btrfs/ordered-data.h | 37 +++++++++++++++++++++++-------------
include/trace/events/btrfs.h | 7 ++++---
4 files changed, 43 insertions(+), 23 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index ef6cb7b620d0..ea9056cc5559 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -917,7 +917,6 @@ static noinline void submit_compressed_extents(struct
async_chunk *async_chunk)
ins.objectid,
async_extent->ram_size,
ins.offset,
- BTRFS_ORDERED_COMPRESSED,
async_extent->compress_type);
if (ret) {
btrfs_drop_extent_cache(inode, async_extent->start,
@@ -1127,7 +1126,8 @@ static noinline int cow_file_range(struct btrfs_inode
*inode,
free_extent_map(em);
ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
- ram_size, cur_alloc_size, 0);
+ ram_size, cur_alloc_size,
+ BTRFS_ORDERED_REGULAR);
if (ret)
goto out_drop_extent_cache;
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index d5d326c674b1..bd7e187d9b16 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -199,8 +199,11 @@ static int __btrfs_add_ordered_extent(struct btrfs_inode
*inode, u64 file_offset
entry->compress_type = compress_type;
entry->truncated_len = (u64)-1;
entry->qgroup_rsv = ret;
- if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
- set_bit(type, &entry->flags);
+
+ ASSERT(type == BTRFS_ORDERED_REGULAR || type == BTRFS_ORDERED_NOCOW ||
+ type == BTRFS_ORDERED_PREALLOC ||
+ type == BTRFS_ORDERED_COMPRESSED);
+ set_bit(type, &entry->flags);
if (dio) {
percpu_counter_add_batch(&fs_info->dio_bytes, num_bytes,
@@ -256,6 +259,8 @@ int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64
file_offset,
u64 disk_bytenr, u64 num_bytes, u64
disk_num_bytes,
int type)
{
+ ASSERT(type == BTRFS_ORDERED_REGULAR || type == BTRFS_ORDERED_NOCOW ||
+ type == BTRFS_ORDERED_PREALLOC);
return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
num_bytes, disk_num_bytes, type, 0,
BTRFS_COMPRESS_NONE);
@@ -265,6 +270,8 @@ int btrfs_add_ordered_extent_dio(struct btrfs_inode *inode,
u64 file_offset,
u64 disk_bytenr, u64 num_bytes,
u64 disk_num_bytes, int type)
{
+ ASSERT(type == BTRFS_ORDERED_REGULAR || type == BTRFS_ORDERED_NOCOW ||
+ type == BTRFS_ORDERED_PREALLOC);
return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
num_bytes, disk_num_bytes, type, 1,
BTRFS_COMPRESS_NONE);
@@ -272,11 +279,12 @@ int btrfs_add_ordered_extent_dio(struct btrfs_inode
*inode, u64 file_offset,
int btrfs_add_ordered_extent_compress(struct btrfs_inode *inode, u64
file_offset,
u64 disk_bytenr, u64 num_bytes,
- u64 disk_num_bytes, int type,
- int compress_type)
+ u64 disk_num_bytes, int compress_type)
{
+ ASSERT(compress_type != BTRFS_COMPRESS_NONE);
return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
- num_bytes, disk_num_bytes, type, 0,
+ num_bytes, disk_num_bytes,
+ BTRFS_ORDERED_COMPRESSED, 0,
compress_type);
}
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index 46194c2c05d4..151ec6bba405 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -27,7 +27,7 @@ struct btrfs_ordered_sum {
};
/*
- * bits for the flags field:
+ * Bits for btrfs_ordered_extent::flags.
*
* BTRFS_ORDERED_IO_DONE is set when all of the blocks are written.
* It is used to make sure metadata is inserted into the tree only once
@@ -38,24 +38,36 @@ struct btrfs_ordered_sum {
* IO is done and any metadata is inserted into the tree.
*/
enum {
+ /*
+ * Different types for direct io, one and only one of the 4 type can
