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author | 2014-10-18 13:32:17 -0700 | |
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committer | 2014-10-18 13:32:17 -0700 | |
commit | ef161ea1ff96337cbe2253afb72636474d90598e (patch) | |
tree | 58fa11ed86de6069d81a5f5b09310ae2a9bd0c70 /fs | |
parent | Merge tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/g... (diff) | |
parent | Revert "Btrfs: race free update of commit root for ro snapshots" (diff) | |
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Merge branch 'for-linus-update' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs data corruption fix from Chris Mason:
"I'm testing a pull with more fixes, but wanted to get this one out so
Greg can pick it up.
The corruption isn't easy to hit, you have to do a readonly snapshot
and have orphans in the snapshot. But my review and testing missed
the bug. Filipe has added a better xfstest to cover it"
* 'for-linus-update' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Revert "Btrfs: race free update of commit root for ro snapshots"
Diffstat (limited to 'fs')
-rw-r--r-- | fs/btrfs/inode.c | 36 | ||||
-rw-r--r-- | fs/btrfs/ioctl.c | 33 |
2 files changed, 33 insertions, 36 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index fc9c0439caa3..d23362f4464e 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -5261,42 +5261,6 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry) iput(inode); inode = ERR_PTR(ret); } - /* - * If orphan cleanup did remove any orphans, it means the tree - * was modified and therefore the commit root is not the same as - * the current root anymore. This is a problem, because send - * uses the commit root and therefore can see inode items that - * don't exist in the current root anymore, and for example make - * calls to btrfs_iget, which will do tree lookups based on the - * current root and not on the commit root. Those lookups will - * fail, returning a -ESTALE error, and making send fail with - * that error. So make sure a send does not see any orphans we - * have just removed, and that it will see the same inodes - * regardless of whether a transaction commit happened before - * it started (meaning that the commit root will be the same as - * the current root) or not. - */ - if (sub_root->node != sub_root->commit_root) { - u64 sub_flags = btrfs_root_flags(&sub_root->root_item); - - if (sub_flags & BTRFS_ROOT_SUBVOL_RDONLY) { - struct extent_buffer *eb; - - /* - * Assert we can't have races between dentry - * lookup called through the snapshot creation - * ioctl and the VFS. - */ - ASSERT(mutex_is_locked(&dir->i_mutex)); - - down_write(&root->fs_info->commit_root_sem); - eb = sub_root->commit_root; - sub_root->commit_root = - btrfs_root_node(sub_root); - up_write(&root->fs_info->commit_root_sem); - free_extent_buffer(eb); - } - } } return inode; diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 0fe1aa047f15..8d2b76e29d3b 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -713,6 +713,39 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir, if (ret) goto fail; + ret = btrfs_orphan_cleanup(pending_snapshot->snap); + if (ret) + goto fail; + + /* + * If orphan cleanup did remove any orphans, it means the tree was + * modified and therefore the commit root is not the same as the + * current root anymore. This is a problem, because send uses the + * commit root and therefore can see inode items that don't exist + * in the current root anymore, and for example make calls to + * btrfs_iget, which will do tree lookups based on the current root + * and not on the commit root. Those lookups will fail, returning a + * -ESTALE error, and making send fail with that error. So make sure + * a send does not see any orphans we have just removed, and that it + * will see the same inodes regardless of whether a transaction + * commit happened before it started (meaning that the commit root + * will be the same as the current root) or not. + */ + if (readonly && pending_snapshot->snap->node != + pending_snapshot->snap->commit_root) { + trans = btrfs_join_transaction(pending_snapshot->snap); + if (IS_ERR(trans) && PTR_ERR(trans) != -ENOENT) { + ret = PTR_ERR(trans); + goto fail; + } + if (!IS_ERR(trans)) { + ret = btrfs_commit_transaction(trans, + pending_snapshot->snap); + if (ret) + goto fail; + } + } + inode = btrfs_lookup_dentry(dentry->d_parent->d_inode, dentry); if (IS_ERR(inode)) { ret = PTR_ERR(inode); |