Neil Horman pointed out a problem where if he did something like this receive A snap A B change B send -p A B and then on another box do recieve A receive B the receive B would fail because we use the UUID of A for the clone sources for B. This makes sense most of the time because normally you are sending from the original sources, not a received source. However when you use a recieved subvol its UUID is going to be something completely different, so if you then try to receive the diff on a different volume it won't find the UUID because the new A will be something else. The only constant is the received uuid. So instead check to see if we have received_uuid set on the root, and if so use that as the clone source, as btrfs receive looks for matches either in received_uuid or uuid. Thanks, Reported-by: Neil Horman <nhorman@redhat.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Reviewed-by: Hugo Mills <hugo@carfax.org.uk> Signed-off-by: Chris Mason <clm@fb.com>
Marc reported a problem where the receiving end of an incremental send
was performing clone operations that failed with -EINVAL. This happened
because, unlike for uncompressed extents, we were not checking if the
source clone offset and length, after summing the data offset, falls
within the source file's boundaries.
So make sure we do such checks when attempting to issue clone operations
for compressed extents.
Problem reproducible with the following steps:
$ mkfs.btrfs -f /dev/sdb
$ mount -o compress /dev/sdb /mnt
$ mkfs.btrfs -f /dev/sdc
$ mount -o compress /dev/sdc /mnt2
# Create the file with a single extent of 128K. This creates a metadata file
# extent item with a data start offset of 0 and a logical length of 128K.
$ xfs_io -f -c "pwrite -S 0xaa 64K 128K" -c "fsync" /mnt/foo
# Now rewrite the range 64K to 112K of our file. This will make the inode's
# metadata continue to point to the 128K extent we created before, but now
# with an extent item that points to the extent with a data start offset of
# 112K and a logical length of 16K.
# That metadata file extent item is associated with the logical file offset
# at 176K and covers the logical file range 176K to 192K.
$ xfs_io -c "pwrite -S 0xbb 64K 112K" -c "fsync" /mnt/foo
# Now rewrite the range 180K to 12K. This will make the inode's metadata
# continue to point the the 128K extent we created earlier, with a single
# extent item that points to it with a start offset of 112K and a logical
# length of 4K.
# That metadata file extent item is associated with the logical file offset
# at 176K and covers the logical file range 176K to 180K.
$ xfs_io -c "pwrite -S 0xcc 180K 12K" -c "fsync" /mnt/foo
$ btrfs subvolume snapshot -r /mnt /mnt/snap1
$ touch /mnt/bar
# Calls the btrfs clone ioctl.
$ ~/xfstests/src/cloner -s $((176 * 1024)) -d $((176 * 1024)) \
-l $((4 * 1024)) /mnt/foo /mnt/bar
$ btrfs subvolume snapshot -r /mnt /mnt/snap2
$ btrfs send /mnt/snap1 | btrfs receive /mnt2
At subvol /mnt/snap1
At subvol snap1
$ btrfs send -p /mnt/snap1 /mnt/snap2 | btrfs receive /mnt2
At subvol /mnt/snap2
At snapshot snap2
ERROR: failed to clone extents to bar
Invalid argument
A test case for fstests follows soon.
Reported-by: Marc MERLIN <marc@merlins.org>
Tested-by: Marc MERLIN <marc@merlins.org>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Tested-by: David Sterba <dsterba@suse.cz>
Tested-by: Jan Alexander Steffens (heftig) <jan.steffens@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>
If a directory inode is orphanized, because some inode previously
processed has a new name that collides with the old name of the current
inode, we need to check if it needs its rename operation delayed too,
as its ancestor-descendent relationship with some other inode might
have been reversed between the parent and send snapshots and therefore
its rename operation needs to happen after that other inode is renamed.
For example, for the following reproducer where this is needed (provided
by Robbie Ko):
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ mkfs.btrfs -f /dev/sdc
$ mount /dev/sdc /mnt2
$ mkdir -p /mnt/data/n1/n2
$ mkdir /mnt/data/n4
$ mkdir -p /mnt/data/t6/t7
$ mkdir /mnt/data/t5
$ mkdir /mnt/data/t7
$ mkdir /mnt/data/n4/t2
$ mkdir /mnt/data/t4
$ mkdir /mnt/data/t3
$ mv /mnt/data/t7 /mnt/data/n4/t2
$ mv /mnt/data/t4 /mnt/data/n4/t2/t7
$ mv /mnt/data/t5 /mnt/data/n4/t2/t7/t4
$ mv /mnt/data/t6 /mnt/data/n4/t2/t7/t4/t5
$ mv /mnt/data/n1/n2 /mnt/data/n4/t2/t7/t4/t5/t6
$ mv /mnt/data/n1 /mnt/data/n4/t2/t7/t4/t5/t6
$ mv /mnt/data/n4/t2/t7/t4/t5/t6/t7 /mnt/data/n4/t2/t7/t4/t5/t6/n2
$ mv /mnt/data/t3 /mnt/data/n4/t2/t7/t4/t5/t6/n2/t7
$ btrfs subvolume snapshot -r /mnt /mnt/snap1
$ mv /mnt/data/n4/t2/t7/t4/t5/t6/n1 /mnt/data/n4
$ mv /mnt/data/n4/t2 /mnt/data/n4/n1
$ mv /mnt/data/n4/n1/t2/t7/t4/t5/t6/n2 /mnt/data/n4/n1/t2
$ mv /mnt/data/n4/n1/t2/n2/t7/t3 /mnt/data/n4/n1/t2
$ mv /mnt/data/n4/n1/t2/t7/t4/t5/t6 /mnt/data/n4/n1/t2
$ mv /mnt/data/n4/n1/t2/t7/t4 /mnt/data/n4/n1/t2/t6
$ mv /mnt/data/n4/n1/t2/t7 /mnt/data/n4/n1/t2/t3
$ mv /mnt/data/n4/n1/t2/n2/t7 /mnt/data/n4/n1/t2
$ btrfs subvolume snapshot -r /mnt /mnt/snap2
$ btrfs send /mnt/snap1 | btrfs receive /mnt2
$ btrfs send -p /mnt/snap1 /mnt/snap2 | btrfs receive /mnt2
ERROR: send ioctl failed with -12: Cannot allocate memory
Where the parent snapshot directory hierarchy is the following:
. (ino 256)
|-- data/ (ino 257)
|-- n4/ (ino 260)
|-- t2/ (ino 265)
|-- t7/ (ino 264)
|-- t4/ (ino 266)
|-- t5/ (ino 263)
|-- t6/ (ino 261)
|-- n1/ (ino 258)
|-- n2/ (ino 259)
|-- t7/ (ino 262)
|-- t3/ (ino 267)
And the send snapshot's directory hierarchy is the following:
. (ino 256)
|-- data/ (ino 257)
|-- n4/ (ino 260)
|-- n1/ (ino 258)
|-- t2/ (ino 265)
|-- n2/ (ino 259)
|-- t3/ (ino 267)
| |-- t7 (ino 264)
|
|-- t6/ (ino 261)
| |-- t4/ (ino 266)
| |-- t5/ (ino 263)
|
|-- t7/ (ino 262)
While processing inode 262 we orphanize inode 264 and later attempt
to rename inode 264 to its new name/location, which resulted in building
an incorrect destination path string for the rename operation with the
value "data/n4/t2/t7/t4/t5/t6/n2/t7/t3/t7". This rename operation must
have been done only after inode 267 is processed and renamed, as the
ancestor-descendent relationship between inodes 264 and 267 was reversed
between both snapshots, because otherwise it results in an infinite loop
when building the path string for inode 264 when we are processing an
inode with a number larger than 264. That loop is the following:
start inode 264, send progress of 265 for example
parent of 264 -> 267
parent of 267 -> 262
parent of 262 -> 259
parent of 259 -> 261
parent of 261 -> 263
parent of 263 -> 266
parent of 266 -> 264
|--> back to first iteration while current path string length
is <= PATH_MAX, and fail with -ENOMEM otherwise
So fix this by making the check if we need to delay a directory rename
regardless of the current inode having been orphanized or not.
A test case for fstests follows soon.
Thanks to Robbie Ko for providing a reproducer for this problem.
Reported-by: Robbie Ko <robbieko@synology.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Even though we delay the rename of directories when they become descendents of other directories that were also renamed in the send root to prevent infinite path build loops, we were doing it in cases where this was not needed and was actually harmful resulting in infinite path build loops as we ended up with a circular dependency of delayed directory renames. Consider the following reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt2 $ mkdir /mnt/data $ mkdir /mnt/data/n1 $ mkdir /mnt/data/n1/n2 $ mkdir /mnt/data/n4 $ mkdir /mnt/data/n1/n2/p1 $ mkdir /mnt/data/n1/n2/p1/p2 $ mkdir /mnt/data/t6 $ mkdir /mnt/data/t7 $ mkdir -p /mnt/data/t5/t7 $ mkdir /mnt/data/t2 $ mkdir /mnt/data/t4 $ mkdir -p /mnt/data/t1/t3 $ mkdir /mnt/data/p1 $ mv /mnt/data/t1 /mnt/data/p1 $ mkdir -p /mnt/data/p1/p2 $ mv /mnt/data/t4 /mnt/data/p1/p2/t1 $ mv /mnt/data/t5 /mnt/data/n4/t5 $ mv /mnt/data/n1/n2/p1/p2 /mnt/data/n4/t5/p2 $ mv /mnt/data/t7 /mnt/data/n4/t5/p2/t7 $ mv /mnt/data/t2 /mnt/data/n4/t1 $ mv /mnt/data/p1 /mnt/data/n4/t5/p2/p1 $ mv /mnt/data/n1/n2 /mnt/data/n4/t5/p2/p1/p2/n2 $ mv /mnt/data/n4/t5/p2/p1/p2/t1 /mnt/data/n4/t5/p2/p1/p2/n2/t1 $ mv /mnt/data/n4/t5/t7 /mnt/data/n4/t5/p2/p1/p2/n2/t1/t7 $ mv /mnt/data/n4/t5/p2/p1/t1/t3 /mnt/data/n4/t5/p2/p1/p2/n2/t1/t3 $ mv /mnt/data/n4/t5/p2/p1/p2/n2/p1 /mnt/data/n4/t5/p2/p1/p2/n2/t1/t7/p1 $ mv /mnt/data/t6 /mnt/data/n4/t5/p2/p1/p2/n2/t1/t3/t5 $ mv /mnt/data/n4/t5/p2/p1/t1 /mnt/data/n4/t5/p2/p1/p2/n2/t1/t3/t1 $ mv /mnt/data/n1 /mnt/data/n4/t5/p2/p1/p2/n2/t1/t7/p1/n1 $ btrfs subvolume snapshot -r /mnt /mnt/snap1 $ mv /mnt/data/n4/t1 /mnt/data/n4/t5/p2/p1/p2/n2/t1/t7/p1/t1 $ mv /mnt/data/n4/t5/p2/p1/p2/n2/t1 /mnt/data/n4/ $ mv /mnt/data/n4/t5/p2/p1/p2/n2 /mnt/data/n4/t1/n2 $ mv /mnt/data/n4/t1/t7/p1 /mnt/data/n4/t1/n2/p1 $ mv /mnt/data/n4/t1/t3/t1 /mnt/data/n4/t1/n2/t1 $ mv /mnt/data/n4/t1/t3 /mnt/data/n4/t1/n2/t1/t3 $ mv /mnt/data/n4/t5/p2/p1/p2 /mnt/data/n4/t1/n2/p1/p2 $ mv /mnt/data/n4/t1/t7 /mnt/data/n4/t1/n2/p1/t7 $ mv /mnt/data/n4/t5/p2/p1 /mnt/data/n4/t1/n2/p1/p2/p1 $ mv /mnt/data/n4/t1/n2/t1/t3/t5 /mnt/data/n4/t1/n2/p1/p2/t5 $ mv /mnt/data/n4/t5 /mnt/data/n4/t1/n2/p1/p2/p1/t5 $ mv /mnt/data/n4/t1/n2/p1/p2/p1/t5/p2 /mnt/data/n4/t1/n2/p1/p2/p1/p2 $ mv /mnt/data/n4/t1/n2/p1/p2/p1/p2/t7 /mnt/data/n4/t1/t7 $ btrfs subvolume snapshot -r /mnt /mnt/snap2 $ btrfs send /mnt/snap1 | btrfs receive /mnt2 $ btrfs send -p /mnt/snap1 /mnt/snap2 | btrfs receive -vv /mnt2 ERROR: send ioctl failed with -12: Cannot allocate memory This reproducer resulted in an infinite path build loop when building the path for inode 266 because the following circular dependency of delayed directory renames was created: ino 272 <- ino 261 <- ino 259 <- ino 268 <- ino 267 <- ino 261 Where the notation "X <- Y" means the rename of inode X is delayed by the rename of inode Y (X will be renamed after Y is renamed). This resulted in an infinite path build loop of inode 266 because that inode has inode 261 as an ancestor in the send root and inode 261 is in the circular dependency of delayed renames listed above. Fix this by not delaying the rename of a directory inode if an ancestor of the inode in the send root, which has a delayed rename operation, is not also a descendent of the inode in the parent root. Thanks to Robbie Ko for sending the reproducer example. A test case for xfstests follows soon. Reported-by: Robbie Ko <robbieko@synology.com> Signed-off-by: Filipe Manana <fdmanana@suse.com>
The logic to detect path loops when attempting to apply a pending directory rename, introduced in commit f959492fc15b (Btrfs: send, fix more issues related to directory renames) is no longer needed, and the respective fstests test case for that commit, btrfs/045, now passes without this code (as well as all the other test cases for send/receive). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
If a directory's reference ends up being orphanized, because the inode currently being processed has a new path that matches that directory's path, make sure we evict the name of the directory from the name cache. This is because there might be descendent inodes (either directories or regular files) that will be orphanized later too, and therefore the orphan name of the ancestor must be used, otherwise we send issue rename operations with a wrong path in the send stream. Reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ mkdir -p /mnt/data/n1/n2/p1/p2 $ mkdir /mnt/data/n4 $ mkdir -p /mnt/data/p1/p2 $ btrfs subvolume snapshot -r /mnt /mnt/snap1 $ mv /mnt/data/p1/p2 /mnt/data $ mv /mnt/data/n1/n2/p1/p2 /mnt/data/p1 $ mv /mnt/data/p2 /mnt/data/n1/n2/p1 $ mv /mnt/data/n1/n2 /mnt/data/p1 $ mv /mnt/data/p1 /mnt/data/n4 $ mv /mnt/data/n4/p1/n2/p1 /mnt/data $ btrfs subvolume snapshot -r /mnt /mnt/snap2 $ btrfs send /mnt/snap1 -f /tmp/1.send $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/2.send $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt2 $ btrfs receive /mnt2 -f /tmp/1.send $ btrfs receive /mnt2 -f /tmp/2.send ERROR: rename data/p1/p2 -> data/n4/p1/p2 failed. no such file or directory Directories data/p1 (inode 263) and data/p1/p2 (inode 264) in the parent snapshot are both orphanized during the incremental send, and as soon as data/p1 is orphanized, we must make sure that when orphanizing data/p1/p2 we use a source path of o263-6-o/p2 for the rename operation instead of the old path data/p1/p2 (the one before the orphanization of inode 263). A test case for xfstests follows soon. Reported-by: Robbie Ko <robbieko@synology.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
If the clone root was not readonly or the dead flag was set on it, we were leaving without decrementing the root's send_progress counter (and before we just incremented it). If a concurrent snapshot deletion was in progress and ended up being aborted, it would be impossible to later attempt to delete again the snapshot, since the root's send_in_progress counter could never go back to 0. We were also setting clone_sources_to_rollback to i + 1 too early - if we bailed out because the clone root we got is not readonly or flagged as dead we ended up later derreferencing a null pointer because we didn't assign the clone root to sctx->clone_roots[i].root: for (i = 0; sctx && i < clone_sources_to_rollback; i++) btrfs_root_dec_send_in_progress( sctx->clone_roots[i].root); So just don't increment the send_in_progress counter if the root is readonly or flagged as dead. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
After we locked the root's root item, a concurrent snapshot deletion call might have set the dead flag on it. So check if the dead flag is set and abort if it is, just like we do for the parent root. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
There's one more case where we can't issue a rename operation for a directory as soon as we process it. We used to delay directory renames only if they have some ancestor directory with a higher inode number that got renamed too, but there's another case where we need to delay the rename too - when a directory A is renamed to the old name of a directory B but that directory B has its rename delayed because it has now (in the send root) an ancestor with a higher inode number that was renamed. If we don't delay the directory rename in this case, the receiving end of the send stream will attempt to rename A to the old name of B before B got renamed to its new name, which results in a "directory not empty" error. So fix this by delaying directory renames for this case too. Steps to reproduce: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ mkdir /mnt/a $ mkdir /mnt/b $ mkdir /mnt/c $ touch /mnt/a/file $ btrfs subvolume snapshot -r /mnt /mnt/snap1 $ mv /mnt/c /mnt/x $ mv /mnt/a /mnt/x/y $ mv /mnt/b /mnt/a $ btrfs subvolume snapshot -r /mnt /mnt/snap2 $ btrfs send /mnt/snap1 -f /tmp/1.send $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/2.send $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt2 $ btrfs receive /mnt2 -f /tmp/1.send $ btrfs receive /mnt2 -f /tmp/2.send ERROR: rename b -> a failed. Directory not empty A test case for xfstests follows soon. Reported-by: Ames Cornish <ames@cornishes.net> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>