btrfs-progs: fix clone from wrong subvolume
v2 cover btrfs-progs: fix clone from wrong subvolume
From: Omar Sandoval <[email protected]>
Hi,
This is a resend of [1] from last July fixing a bug when the same subvolume is received multiple times. It appears that the series got lost at some point.
The only changes from v2 are adding Filipe's reviewed-bys and removing the strdup cleanup patch that was already merged. Based on the devel branch.
Thanks!
1: https://lore.kernel.org/linux-btrfs/[email protected]/
Omar Sandoval (3):
btrfs-progs: receive: remove commented out transid checks
btrfs-progs: receive: don't lookup clone root for received subvolume
btrfs-progs: tests: add test for receiving clone from duplicate
subvolume
cmds/receive.c | 43 ++++--------------- .../test.sh | 34 +++++++++++++++ 2 files changed, 42 insertions(+), 35 deletions(-) create mode 100755 tests/misc-tests/038-receive-clone-from-current-subvolume/test.sh
Signature · 1 line
2.25.1
PATCH RESEND v2 1/3 btrfs-progs: receive: remove commented out transid checks
From: Omar Sandoval <[email protected]>
The checks for a subvolume being modified after it was received have been commented out since they were added back in commit f1c24cd80dfd ("Btrfs-progs: add btrfs send/receive commands"). Let's just get rid of the noise.
--- cmds/receive.c | 25 ------------------------- 1 file changed, 25 deletions(-)
cmds/receive.c +0 -25
@@ -345,15 +345,6 @@ static int process_snapshot(const char *path, const u8 *uuid, u64 ctransid, parent_subvol->path[sub_len - root_len -1 ] ='\0' ; } } -/*if (rs_args.ctransid > rs_args.rtransid) { -if (!r->force) { -ret = -EINVAL; -fprintf(stderr, "ERROR: subvolume %s was modified after it was received.\n", r->subvol_parent_name); -goto out; -} else { -fprintf(stderr, "WARNING: subvolume %s was modified after it was received.\n", r->subvol_parent_name); -} -}*/ if (*parent_subvol->path ==0 ) args_v2.fd =dup (rctx->mnt_fd);
@@ -771,22 +762,6 @@ static int process_clone(const char *path, u64 offset, u64 len, goto out; } }else { -/*if (rs_args.ctransid > rs_args.rtransid) { -if (!r->force) { -ret = -EINVAL; -fprintf(stderr, "ERROR: subvolume %s was " -"modified after it was " -"received.\n", -r->subvol_parent_name); -goto out; -} else { -fprintf(stderr, "WARNING: subvolume %s was " -"modified after it was " -"received.\n", -r->subvol_parent_name); -} -}*/ -/* strip the subvolume that we are receiving to from the start of subvol_path */ if (rctx->full_root_path) {size_t root_len =strlen (rctx->full_root_path);
Signature · 1 line
2.25.1
PATCH RESEND v2 2/3 btrfs-progs: receive: don't lookup clone root for received subvolume
In reply to Omar SandovalFrom: Omar Sandoval <[email protected]>
When we process a clone request, we look up the source subvolume by UUID, even if the source is the subvolume that we're currently receiving. Usually, this is fine. However, if for some reason we previously received the same subvolume, then this will use paths relative to the previously received subvolume instead of the current one. This is incorrect, since the send stream may use temporary names for the clone source. This can be reproduced as follows:
btrfs subvolume create subvol
dd if=/dev/urandom of=subvol/foo bs=1M count=1
cp --reflink subvol/foo subvol/bar
mkdir subvol/dir
mv subvol/foo subvol/dir/
btrfs property set subvol ro true
btrfs send -f send.data subvol
mkdir first second
btrfs receive -f send.data first
btrfs receive -f send.data second
The second receive results in this error:
ERROR: cannot open first/subvol/o259-7-0/foo: No such file or directory
Fix it by always cloning from the current subvolume if its UUID matches. This has the nice side effect of avoiding unnecessary UUID tree lookups in that case.
--- cmds/receive.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-)
cmds/receive.c +8 -10
@@ -745,15 +745,14 @@ static int process_clone(const char *path, u64 offset, u64 len,if (ret <0 ) goto out; - si =subvol_uuid_search (&rctx->sus,0 , clone_uuid, clone_ctransid, -NULL , - subvol_search_by_received_uuid); -if (IS_ERR_OR_NULL (si)) { -if (memcmp (clone_uuid, rctx->cur_subvol.received_uuid, -BTRFS_UUID_SIZE ) ==0 ) { -/* TODO check generation of extent */ - subvol_path = rctx->cur_subvol_path; - }else { +if (memcmp (clone_uuid, rctx->cur_subvol.received_uuid, +BTRFS_UUID_SIZE ) ==0 ) { + subvol_path = rctx->cur_subvol_path; + }else { + si =subvol_uuid_search (&rctx->sus,0 , clone_uuid, clone_ctransid, +NULL , + subvol_search_by_received_uuid); +if (IS_ERR_OR_NULL (si)) {if (!si) ret = -ENOENT ;else
@@ -761,7 +760,6 @@ static int process_clone(const char *path, u64 offset, u64 len,error ("clone: did not find source subvol" ); goto out; } - }else {/* strip the subvolume that we are receiving to from the start of subvol_path */ if (rctx->full_root_path) {size_t root_len =strlen (rctx->full_root_path);
Signature · 1 line
2.25.1
PATCH RESEND v2 3/3 btrfs-progs: tests: add test for receiving clone from duplicate subvolume
In reply to Omar SandovalFrom: Omar Sandoval <[email protected]>
This test case is the reproducer for the previous fix.
--- .../test.sh | 34 +++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100755 tests/misc-tests/038-receive-clone-from-current-subvolume/test.sh
tests/misc-tests/038-receive-clone-from-current-subvolume/test.sh new file +34 -0
@@ -0,0 +1,34 @@ +#!/bin/bash +# Test that when receiving a subvolume whose received UUID already exists in +# the filesystem, we clone from the correct source (the subvolume that we are +# receiving, not the existing subvolume). This is a regression test for +# "btrfs-progs: receive: don't lookup clone root for received subvolume". + +source "$TEST_TOP/common" + +check_prereq btrfs +check_prereq mkfs.btrfs + +setup_root_helper + +rm -f disk +run_check truncate -s 1G disk +chmod a+w disk +run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -f disk +run_check $SUDO_HELPER mount -o loop disk "$TEST_MNT" + +run_check $SUDO_HELPER "$TOP/btrfs" subvolume create "$TEST_MNT/subvol" +run_check $SUDO_HELPER dd if=/dev/urandom of="$TEST_MNT/subvol/foo" \ + bs=1M count=1 status=none +run_check $SUDO_HELPER cp --reflink "$TEST_MNT/subvol/foo" "$TEST_MNT/subvol/bar" +run_check $SUDO_HELPER mkdir "$TEST_MNT/subvol/dir" +run_check $SUDO_HELPER mv "$TEST_MNT/subvol/foo" "$TEST_MNT/subvol/dir" +run_check $SUDO_HELPER "$TOP/btrfs" property set "$TEST_MNT/subvol" ro true +run_check $SUDO_HELPER "$TOP/btrfs" send -f send.data "$TEST_MNT/subvol" + +run_check $SUDO_HELPER mkdir "$TEST_MNT/first" "$TEST_MNT/second" +run_check $SUDO_HELPER "$TOP/btrfs" receive -f send.data "$TEST_MNT/first" +run_check $SUDO_HELPER "$TOP/btrfs" receive -f send.data "$TEST_MNT/second" + +run_check $SUDO_HELPER umount "$TEST_MNT" +rm -f disk send.data
Signature · 1 line
2.25.1
Re: [PATCH RESEND v2 1/3] btrfs-progs: receive: remove commented out transid checks
In reply to Omar SandovalQuoted 7 lines · Omar Sandoval
From: Omar Sandoval <[email protected]>
The checks for a subvolume being modified after it was received have been commented out since they were added back in commit
f1c24cd80dfd("Btrfs-progs: add btrfs send/receive commands"). Let's just get rid of the noise.
Indeed. If they were ever in place, it would have never been possible to do an incremental send and running dedupe against the parent snapshot.
That particular use case used to cause send, the kernel side, to fail (initially with a BUG_ON() and later with -EIO returned to user space):
If this code in btrfs-progs was not commented, it would have been easier to find that problem.
Thanks.
Quoted 52 lines
Signed-off-by Omar Sandoval <[email protected]>--- cmds/receive.c | 25 ------------------------- 1 file changed, 25 deletions(-)cmds/receive.c +0
-26@@ -345,15 +345,6 @@ static int process_snapshot(const char *path, const u8 *uuid, u64 ctransid, parent_subvol->path[sub_len - root_len -1 ] ='\0' ; } } -/*if (rs_args.ctransid > rs_args.rtransid) { -if (!r->force) { -ret = -EINVAL; -fprintf(stderr, "ERROR: subvolume %s was modified after it was received.\n", r->subvol_parent_name); -goto out; -} else { -fprintf(stderr, "WARNING: subvolume %s was modified after it was received.\n", r->subvol_parent_name); -} -}*/ if (*parent_subvol->path ==0 ) args_v2.fd =dup (rctx->mnt_fd);@@ -771,22 +762,6 @@ static int process_clone(const char *path, u64 offset, u64 len, goto out; } }else { -/*if (rs_args.ctransid > rs_args.rtransid) { -if (!r->force) { -ret = -EINVAL; -fprintf(stderr, "ERROR: subvolume %s was " -"modified after it was " -"received.\n", -r->subvol_parent_name); -goto out; -} else { -fprintf(stderr, "WARNING: subvolume %s was " -"modified after it was " -"received.\n", -r->subvol_parent_name); -} -}*/ -/* strip the subvolume that we are receiving to from the start of subvol_path */ if (rctx->full_root_path) {size_t root_len =strlen (rctx->full_root_path); --2.25.1
Signature · 3 lines
Filipe David Manana, “Whether you think you can, or you think you can't — you're right.”
Re: [PATCH RESEND v2 3/3] btrfs-progs: tests: add test for receiving clone from duplicate subvolume
In reply to Omar SandovalQuoted 25 lines · Omar Sandoval
From: Omar Sandoval <[email protected]>
This test case is the reproducer for the previous fix.
Reviewed-by Filipe Manana <[email protected]>Signed-off-by Omar Sandoval <[email protected]>--- .../test.sh | 34 +++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100755 tests/misc-tests/038-receive-clone-from-current-subvolume/test.shtests/misc-tests/038-receive-clone-from-current-subvolume/test.sh new file +8
-0@@ -0,0 +1,34 @@ +#!/bin/bash +# Test that when receiving a subvolume whose received UUID already exists in +# the filesystem, we clone from the correct source (the subvolume that we are +# receiving, not the existing subvolume). This is a regression test for +# "btrfs-progs: receive: don't lookup clone root for received subvolume". + +source "$TEST_TOP/common" +
tests/misc-tests/038-receive-clone-from-current-subvolume/test.sh line 18
Quoted 10 lines
tests/misc-tests/038-receive-clone-from-current-subvolume/test.sh new file +10
-0+check_prereq btrfs +check_prereq mkfs.btrfs + +setup_root_helper + +rm -f disk +run_check truncate -s 1G disk +chmod a+w disk +run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -f disk +run_check $SUDO_HELPER mount -o loop disk "$TEST_MNT"
I don't see any special reason to use the loop device (like an additional one to the default), so I think this should be fine using the default image and the common helpers.
tests/misc-tests/038-receive-clone-from-current-subvolume/test.sh line 31
Quoted 12 lines
tests/misc-tests/038-receive-clone-from-current-subvolume/test.sh new file +12
-0+run_check $SUDO_HELPER "$TOP/btrfs" subvolume create "$TEST_MNT/subvol" +run_check $SUDO_HELPER dd if=/dev/urandom of="$TEST_MNT/subvol/foo" \ + bs=1M count=1 status=none +run_check $SUDO_HELPER cp --reflink "$TEST_MNT/subvol/foo" "$TEST_MNT/subvol/bar" +run_check $SUDO_HELPER mkdir "$TEST_MNT/subvol/dir" +run_check $SUDO_HELPER mv "$TEST_MNT/subvol/foo" "$TEST_MNT/subvol/dir" +run_check $SUDO_HELPER "$TOP/btrfs" property set "$TEST_MNT/subvol" ro true +run_check $SUDO_HELPER "$TOP/btrfs" send -f send.data "$TEST_MNT/subvol" + +run_check $SUDO_HELPER mkdir "$TEST_MNT/first" "$TEST_MNT/second" +run_check $SUDO_HELPER "$TOP/btrfs" receive -f send.data "$TEST_MNT/first" +run_check $SUDO_HELPER "$TOP/btrfs" receive -f send.data "$TEST_MNT/second"
All paths are inside $TEST_MNT, so a 'cd' into the directory would save some typing. I'll fix it.