From: Omar Sandoval <osandov@xxxxxx>
Jun Wu at Facebook reported that an internal service was seeing a return
value of 1 from ftruncate() on Btrfs when compression is enabled. This
is coming from the NEED_TRUNCATE_BLOCK return value from
btrfs_truncate_inode_items().
btrfs_truncate() uses two variables for error handling, ret and err (if
this sounds familiar, it's because btrfs_truncate_inode_items() does
something similar). When btrfs_truncate_inode_items() returns non-zero,
we set err to the return value, but we don't reset it to zero in the
successful NEED_TRUNCATE_BLOCK case. We only have err because we don't
want to mask an error if we call btrfs_update_inode() and
btrfs_end_transaction(), so let's make that its own scoped return
variable and use ret everywhere else.
Fixes: ddfae63cc8e0 ("btrfs: move btrfs_truncate_block out of trans handle")
Reported-by: Jun Wu <quark@xxxxxx>
Signed-off-by: Omar Sandoval <osandov@xxxxxx>
---
This is based on Linus' master rather than my orphan ENOSPC fixes
because I think we want to get this in for v4.17 and stable, and rebase
my fixes on top of this.
fs/btrfs/inode.c | 34 ++++++++++++++--------------------
1 file changed, 14 insertions(+), 20 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index d241285a0d2a..d4a47ae36ed8 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -9031,8 +9031,7 @@ static int btrfs_truncate(struct inode *inode, bool skip_writeback)
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_block_rsv *rsv;
- int ret = 0;
- int err = 0;
+ int ret;
struct btrfs_trans_handle *trans;
u64 mask = fs_info->sectorsize - 1;
u64 min_size = btrfs_calc_trunc_metadata_size(fs_info, 1);
@@ -9092,7 +9091,7 @@ static int btrfs_truncate(struct inode *inode, bool skip_writeback)
*/
trans = btrfs_start_transaction(root, 2);
if (IS_ERR(trans)) {
- err = PTR_ERR(trans);
+ ret = PTR_ERR(trans);
goto out;
}
@@ -9116,23 +9115,19 @@ static int btrfs_truncate(struct inode *inode, bool skip_writeback)
inode->i_size,
BTRFS_EXTENT_DATA_KEY);
trans->block_rsv = &fs_info->trans_block_rsv;
- if (ret != -ENOSPC && ret != -EAGAIN) {
- err = ret;
+ if (ret != -ENOSPC && ret != -EAGAIN)
break;
- }
ret = btrfs_update_inode(trans, root, inode);
- if (ret) {
- err = ret;
+ if (ret)
break;
- }
btrfs_end_transaction(trans);
btrfs_btree_balance_dirty(fs_info);
trans = btrfs_start_transaction(root, 2);
if (IS_ERR(trans)) {
- ret = err = PTR_ERR(trans);
+ ret = PTR_ERR(trans);
trans = NULL;
break;
}
@@ -9168,26 +9163,25 @@ static int btrfs_truncate(struct inode *inode, bool skip_writeback)
if (ret == 0 && inode->i_nlink > 0) {
trans->block_rsv = root->orphan_block_rsv;
ret = btrfs_orphan_del(trans, BTRFS_I(inode));
- if (ret)
- err = ret;
}
if (trans) {
+ int ret2;
+
trans->block_rsv = &fs_info->trans_block_rsv;
- ret = btrfs_update_inode(trans, root, inode);
- if (ret && !err)
- err = ret;
+ ret2 = btrfs_update_inode(trans, root, inode);
+ if (ret2 && !ret)
+ ret = ret2;
- ret = btrfs_end_transaction(trans);
+ ret2 = btrfs_end_transaction(trans);
+ if (ret2 && !ret)
+ ret = ret2;
btrfs_btree_balance_dirty(fs_info);
}
out:
btrfs_free_block_rsv(fs_info, rsv);
- if (ret && !err)
- err = ret;
-
- return err;
+ return ret;
}
/*
--
2.17.0
--
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