Alexander,
(pls let me know when this gets annoying:).
Parent:
/mnt/src/v2_snap0/
└── [ 257] file1
Send:
/mnt/src/v2_snap1
└── [ 259] dir1
└── [ 258] dir2
└── [ 257] file1
I encountered two problems:
1) process_recorded_refs_if_needed() if needed does not call
process_recorded_refs() if both new_refs and deleted_refs() are empty.
But in this case, we need to get to finish_outoforder_dir() by dir2 to
move file1 under it (this is before dir1 is created).
@@ -4199,8 +4227,25 @@ static int
process_recorded_refs_if_needed(struct send_ctx *sctx, int at_end)
if (!at_end && sctx->cur_ino == sctx->cmp_key->objectid &&
sctx->cmp_key->type <= BTRFS_INODE_REF_KEY)
goto out;
- if (list_empty(&sctx->new_refs) && list_empty(&sctx->deleted_refs))
- goto out;
+ if (list_empty(&sctx->new_refs) && list_empty(&sctx->deleted_refs) &&
+ /*
+ * If this is a new directory, still do the
finish_outoforder_dir() thing,
+ * even though it has no references recorded. This
means that the directory's
+ * parent has higher inode and was not created yet
(thus we should have
+ * sctx->cur_inode_first_ref_orphan flag set).
+ * Note that after a call to process_recorded_refs(),
new_refs and deleted_refs
+ * become empty, which prevents further calls to
process_recorded_refs(),
+ * but here we need something else to prevent it, so
look at send_progress too.
+ */
+ !(S_ISDIR(sctx->cur_inode_mode) && sctx->cur_inode_new &&
+ sctx->cur_inode_first_ref_orphan &&
sctx->send_progress == sctx->cur_ino))
+ goto out;
ret = process_recorded_refs(sctx);
Then I encountered another problem that finish_outoforder_dir() does
not check for itself the cur_inode_first_ref_orphan flag:
@@ -2736,7 +2754,17 @@ static int finish_outoforder_dir(struct
send_ctx *sctx, u64 dir, u64 dir_gen)
}
fctx.dir_ino = dir;
- ret = get_cur_path(sctx, dir, dir_gen, fctx.dir_path, 1/*do_print*/);
+ /*
+ * If the current directory itself has a parent, which was not
+ * created yet, we need to use gen_unique_name().
+ */
+ BUG_ON(sctx->cur_ino != dir || sctx->cur_inode_gen != dir_gen);
+ if (sctx->cur_inode_first_ref_orphan)
+ ret = gen_unique_name(sctx, dir, dir_gen, fctx.dir_path);
+ else
+ ret = get_cur_path(sctx, dir, dir_gen, fctx.dir_path);
Finally, the send_truncate(), send_chmod(), send_chown(),send_utimes()
need the following check:
if (sctx->cur_ino == ino && sctx->cur_inode_first_ref_orphan) {
WARN_ON(sctx->cur_inode_gen != gen);
ret = gen_unique_name(sctx, ino, gen, p);
} else {
ret = get_cur_path(sctx, ino, gen, p);
}
All of them except utimes() are used with cur_ino only, so for those
this check is redundant (and probably makes sense to drop ino/gen
parameters of them?).
Thanks,
Alex.
On Thu, Jul 26, 2012 at 1:52 PM, Alex Lyakas
<alex.bolshoy.bt...@gmail.com> wrote:
> Hi Alexander,
> I did some very initial testing, and there is still an issue.
> The logic of finish_outoforder_dir works as expected. But then problem
> is that later, when we process xattr/extents or finish the inode, the
> code still uses get_cur_path(), which brings an incorrect name.
>
> Consider the following simple scenario:
>
> Parent tree:
> /mnt/src/v2
> └── [ 260] file1
>
> Send tree:
> /mnt/src/v2
> └── [ 262] dir1
> └── [ 260] file1
>
> So when file1 is being processed, it is first renamed, as expected:
> C_RENAME: A_PATH=file1, A_PATH_TO=o260-511-0
> But then, when we finish it, we do:
> C_TRUNCATE: A_PATH=o262-517-0/file1, A_SIZE=16
>
> So in some functions like send_truncate(), send_write(), send_utimes()
> etc, we need:
>
> - ret = get_cur_path(sctx, ino, gen, p, 0/*do_print*/);
> + if (sctx->cur_inode_first_ref_orphan)
> + ret = gen_unique_name(sctx, ino, gen, p);
> + else
> + ret = get_cur_path(sctx, ino, gen, p, 0/*do_print*/);
> if (ret < 0)
> goto out;
>
> I will continue testing more complicated cases now.
>
> Thanks,
> Alex.
>
>
>
>
>
>
>
>
> On Tue, Jul 24, 2012 at 11:26 PM, Alexander Block
> <abloc...@googlemail.com> wrote:
>> On Wed, Jul 18, 2012 at 7:45 PM, Alex Lyakas
>> <alex.bolshoy.bt...@gmail.com> wrote:
>>> Hi Alexander,
>>> I am testing different scenarios in order to better understand the
>>> non-trivial magic of
>>> get_cur_path()/will_overwrite_ref()/did_overwrite_ref()/did_overwrite_first_ref().
>>> I hit the following issue, when testing full-send:
>>>
>>> This is my source subvolume (inode numbers are written):
>>> tree -A --inodes --noreport /mnt/src/tmp/
>>> /mnt/src/tmp/
>>> └── [ 270] dir2
>>> └── [ 268] file1_nod
>>>
>>> As you see, the ino(file1_nod) < ino(dir2). It is very easy to
>>> achieve: first create the file, then the dir, and then move the file
>>> to dir.
>>>
>>> During send the following happens (I augmented the send code with many
>>> prints):
>>>
>>> file1_nod is sent first. Since its a new inode, it is sent as an
>>> orphan. When recording its reference, __record_new_ref() calls
>>> get_cur_path() for its parent (270). Then __get_cur_name_and_parent()
>>> is called on 270, which calls is_inode_existent(), which calls
>>> get_cur_inode_state(), and the state of the parent is "will_create".
>>> So __get_cur_name_and_parent() creates an orphan name for it, and
>>> finally the new reference for 268 is recorded as:
>>> o270-136-0/file1_nod:
>>>
>>> [changed_cb:4102] key(256 INODE_ITEM 0) : NEW
>>> [changed_cb:4102] key(256 INODE_REF 256) : NEW
>>> [changed_cb:4102] key(268 INODE_ITEM 0) : NEW
>>> [send_create_inode:2407] NEW ino(268,135) type=0100000, path=[o268-135-0]
>>> [changed_cb:4102] key(268 INODE_REF 270) : NEW
>>> [get_cur_inode_state:1475] (270,136): L(EX,136)
>>> R(NE,18446744072099047770) sp=268 ==> will_create
>>> [is_inode_existent:1498] (270,136): NOT existent
>>> [__get_cur_name_and_parent:1918] ino(270,136) not existent => unique
>>> name [o270-136-0]
>>> [get_cur_path:2051] ino(0,0) cur_path=[o270-136-0]
>>> [__record_new_ref:2911] record new ref [o270-136-0/file1_nod]
>>>
>>> Then process_recorded_refs() sees that 268 is still orphan, so it
>>> sends "rename" to its valid place, but the problem is that its parent
>>> dir was not sent yet (and its parent dir is also an orphan):
>>> [process_recorded_refs:2601] ino(268,135): start with refs
>>> [28118.347602] [process_recorded_refs:2651] ino(268,135): new=1,
>>> did_overwrite_first_ref=0, is_orphan=1, valid_path=[o268-135-0]
>>> [28118.347605] [process_recorded_refs:2701] ino(268,135): is orphan,
>>> move it: [o268-135-0]=>[o270-136-0/file1_nod]
>>> [28118.347610] [process_recorded_refs:2837] checking dir(270,136)
>>> [28118.347612] [process_recorded_refs:2869] ino(268,135) done with refs
>>>
>>> Now the parent dir is processed:
>>> [changed_cb:4102] key(270 INODE_ITEM 0) : NEW
>>> [send_create_inode:2407] NEW ino(270,136) type=040000, path=[o270-136-0]
>>> [changed_cb:4102] key(270 INODE_REF 256) : NEW
>>> [get_cur_path:2051] ino(256,133) cur_path=[]
>>> [__record_new_ref:2911] record new ref [dir2]
>>> [process_recorded_refs:2601] ino(270,136): start with refs
>>> [process_recorded_refs:2651] ino(270,136): new=1,
>>> did_overwrite_first_ref=0, is_orphan=1, valid_path=[o270-136-0]
>>> [process_recorded_refs:2701] ino(270,136): is orphan, move it:
>>> [o270-136-0]=>[dir2]
>>> [process_recorded_refs:2837] checking dir(256,133)
>>> [get_cur_inode_state:1475] (256,133): L(EX,133)
>>> R(NE,18446612135413283512) sp=270 ==> did_create
>>> [process_recorded_refs:2869] ino(270,136) done with refs
>>>
>>> Nothing special here, the parent is first sent as an orphan, and then
>>> renamed to its valid name, but it's too late.
>>>
>>> During receive:
>>> ERROR: rename o268-135-0 -> o270-136-0/file1_nod failed. No such file
>>> or directory
>>>
>>> I am not yet sure where is the proper place to fix this, I just wanted
>>> to report it first. Basically, I think that when sending any kind of
>>> A_PATH, it is needed to ensure that path components exist, either as
>>> orphan or real path (by sending them out-of-order if needed?). But I
>>> am not yet sure where is the core place that should ensure this.
>>>
>>> Thanks,
>>> Alex.
>>
>> I have pushed a fix for this case. Basically, the solution is to
>> postpone the processing of refs in not created dirs until the dir is
>> created. Big thanks for investigating this one.
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