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authorNikolay Borisov <nborisov@suse.com>2019-10-08 19:43:06 +0200
committerDavid Sterba <dsterba@suse.com>2019-11-18 12:46:54 +0100
commit8d510121bfbf87302e0594d2022c5e7d52b26f7f (patch)
tree4db97054562c8476d848c0b823d723eb9627c57c /fs/btrfs
parentbtrfs: User assert to document transaction requirement (diff)
downloadlinux-8d510121bfbf87302e0594d2022c5e7d52b26f7f.tar.xz
linux-8d510121bfbf87302e0594d2022c5e7d52b26f7f.zip
btrfs: Rename btrfs_join_transaction_nolock
This function is used only during the final phase of freespace cache writeout. This is necessary since using the plain btrfs_join_transaction api is deadlock prone. The deadlock looks like: T1: btrfs_commit_transaction commit_cowonly_roots btrfs_write_dirty_block_groups btrfs_wait_cache_io __btrfs_wait_cache_io btrfs_wait_ordered_range <-- Triggers ordered IO for freespace inode and blocks transaction commit until freespace cache writeout T2: <-- after T1 has triggered the writeout finish_ordered_fn btrfs_finish_ordered_io btrfs_join_transaction <--- this would block waiting for current transaction to commit, but since trans commit is waiting for this writeout to finish The special purpose functions prevents it by simply skipping the "wait for writeout" since it's guaranteed the transaction won't proceed until we are done. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/inode.c12
-rw-r--r--fs/btrfs/transaction.c2
-rw-r--r--fs/btrfs/transaction.h2
3 files changed, 8 insertions, 8 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 7ed0fe2dd5ba..3315a6eb09a3 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3066,7 +3066,7 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
int compress_type = 0;
int ret = 0;
u64 logical_len = ordered_extent->len;
- bool nolock;
+ bool freespace_inode;
bool truncated = false;
bool range_locked = false;
bool clear_new_delalloc_bytes = false;
@@ -3077,7 +3077,7 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
!test_bit(BTRFS_ORDERED_DIRECT, &ordered_extent->flags))
clear_new_delalloc_bytes = true;
- nolock = btrfs_is_free_space_inode(BTRFS_I(inode));
+ freespace_inode = btrfs_is_free_space_inode(BTRFS_I(inode));
if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
ret = -EIO;
@@ -3108,8 +3108,8 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
btrfs_qgroup_free_data(inode, NULL, ordered_extent->file_offset,
ordered_extent->len);
btrfs_ordered_update_i_size(inode, 0, ordered_extent);
- if (nolock)
- trans = btrfs_join_transaction_nolock(root);
+ if (freespace_inode)
+ trans = btrfs_join_transaction_spacecache(root);
else
trans = btrfs_join_transaction(root);
if (IS_ERR(trans)) {
@@ -3143,8 +3143,8 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
EXTENT_DEFRAG, 0, 0, &cached_state);
}
- if (nolock)
- trans = btrfs_join_transaction_nolock(root);
+ if (freespace_inode)
+ trans = btrfs_join_transaction_spacecache(root);
else
trans = btrfs_join_transaction(root);
if (IS_ERR(trans)) {
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 54b8718054ce..6f133906c862 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -729,7 +729,7 @@ struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
true);
}
-struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
+struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root)
{
return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
BTRFS_RESERVE_NO_FLUSH, true);
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 2ac89fb0d709..49f7196368f5 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -183,7 +183,7 @@ struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
unsigned int num_items,
int min_factor);
struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root);
-struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root);
+struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root);
struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root);
struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root);
struct btrfs_trans_handle *btrfs_attach_transaction_barrier(