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From: Josh Boyer <jwboyer@fedoraproject.org>
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Date: Wed, 15 Oct 2014 10:09:50 -0400
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Subject: [PATCH] Revert "Btrfs: race free update of commit root for ro
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snapshots"
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This reverts commit 9c3b306e1c9e6be4be09e99a8fe2227d1005effc.
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---
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fs/btrfs/inode.c | 36 ------------------------------------
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fs/btrfs/ioctl.c | 33 +++++++++++++++++++++++++++++++++
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2 files changed, 33 insertions(+), 36 deletions(-)
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diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
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index fc9c0439caa3..d23362f4464e 100644
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--- a/fs/btrfs/inode.c
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+++ b/fs/btrfs/inode.c
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@@ -5261,42 +5261,6 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
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iput(inode);
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inode = ERR_PTR(ret);
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}
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- /*
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- * If orphan cleanup did remove any orphans, it means the tree
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- * was modified and therefore the commit root is not the same as
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- * the current root anymore. This is a problem, because send
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- * uses the commit root and therefore can see inode items that
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- * don't exist in the current root anymore, and for example make
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- * calls to btrfs_iget, which will do tree lookups based on the
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- * current root and not on the commit root. Those lookups will
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- * fail, returning a -ESTALE error, and making send fail with
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- * that error. So make sure a send does not see any orphans we
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- * have just removed, and that it will see the same inodes
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- * regardless of whether a transaction commit happened before
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- * it started (meaning that the commit root will be the same as
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- * the current root) or not.
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- */
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- if (sub_root->node != sub_root->commit_root) {
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- u64 sub_flags = btrfs_root_flags(&sub_root->root_item);
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-
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- if (sub_flags & BTRFS_ROOT_SUBVOL_RDONLY) {
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- struct extent_buffer *eb;
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-
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- /*
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- * Assert we can't have races between dentry
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- * lookup called through the snapshot creation
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- * ioctl and the VFS.
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- */
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- ASSERT(mutex_is_locked(&dir->i_mutex));
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-
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- down_write(&root->fs_info->commit_root_sem);
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- eb = sub_root->commit_root;
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- sub_root->commit_root =
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- btrfs_root_node(sub_root);
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- up_write(&root->fs_info->commit_root_sem);
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- free_extent_buffer(eb);
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- }
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- }
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}
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return inode;
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diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
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index 0fe1aa047f15..8d2b76e29d3b 100644
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--- a/fs/btrfs/ioctl.c
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+++ b/fs/btrfs/ioctl.c
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@@ -713,6 +713,39 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir,
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if (ret)
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goto fail;
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+ ret = btrfs_orphan_cleanup(pending_snapshot->snap);
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+ if (ret)
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+ goto fail;
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+
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+ /*
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+ * If orphan cleanup did remove any orphans, it means the tree was
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+ * modified and therefore the commit root is not the same as the
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+ * current root anymore. This is a problem, because send uses the
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+ * commit root and therefore can see inode items that don't exist
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+ * in the current root anymore, and for example make calls to
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+ * btrfs_iget, which will do tree lookups based on the current root
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+ * and not on the commit root. Those lookups will fail, returning a
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+ * -ESTALE error, and making send fail with that error. So make sure
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+ * a send does not see any orphans we have just removed, and that it
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+ * will see the same inodes regardless of whether a transaction
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+ * commit happened before it started (meaning that the commit root
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+ * will be the same as the current root) or not.
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+ */
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+ if (readonly && pending_snapshot->snap->node !=
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+ pending_snapshot->snap->commit_root) {
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+ trans = btrfs_join_transaction(pending_snapshot->snap);
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+ if (IS_ERR(trans) && PTR_ERR(trans) != -ENOENT) {
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+ ret = PTR_ERR(trans);
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+ goto fail;
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+ }
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+ if (!IS_ERR(trans)) {
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+ ret = btrfs_commit_transaction(trans,
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+ pending_snapshot->snap);
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+ if (ret)
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+ goto fail;
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+ }
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+ }
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+
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inode = btrfs_lookup_dentry(dentry->d_parent->d_inode, dentry);
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if (IS_ERR(inode)) {
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ret = PTR_ERR(inode);
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--
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1.9.3
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