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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- reject unknown mount options
- adjust transaction abort error message level
- fix one more build warning with -Wmaybe-uninitialized
- proper error handling in several COW-related cases
* tag 'for-6.6-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: error out when reallocating block for defrag using a stale transaction
btrfs: error when COWing block from a root that is being deleted
btrfs: error out when COWing block using a stale transaction
btrfs: always print transaction aborted messages with an error level
btrfs: reject unknown mount options early
btrfs: fix some -Wmaybe-uninitialized warnings in ioctl.c
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At btrfs_realloc_node() we have these checks to verify we are not using a
stale transaction (a past transaction with an unblocked state or higher),
and the only thing we do is to trigger two WARN_ON(). This however is a
critical problem, highly unexpected and if it happens it's most likely due
to a bug, so we should error out and turn the fs into error state so that
such issue is much more easily noticed if it's triggered.
The problem is critical because in btrfs_realloc_node() we COW tree blocks,
and using such stale transaction will lead to not persisting the extent
buffers used for the COW operations, as allocating tree block adds the
range of the respective extent buffers to the ->dirty_pages iotree of the
transaction, and a stale transaction, in the unlocked state or higher,
will not flush dirty extent buffers anymore, therefore resulting in not
persisting the tree block and resource leaks (not cleaning the dirty_pages
iotree for example).
So do the following changes:
1) Return -EUCLEAN if we find a stale transaction;
2) Turn the fs into error state, with error -EUCLEAN, so that no
transaction can be committed, and generate a stack trace;
3) Combine both conditions into a single if statement, as both are related
and have the same error message;
4) Mark the check as unlikely, since this is not expected to ever happen.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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At btrfs_cow_block() we check if the block being COWed belongs to a root
that is being deleted and if so we log an error message. However this is
an unexpected case and it indicates a bug somewhere, so we should return
an error and abort the transaction. So change this in the following ways:
1) Abort the transaction with -EUCLEAN, so that if the issue ever happens
it can easily be noticed;
2) Change the logged message level from error to critical, and change the
message itself to print the block's logical address and the ID of the
root;
3) Return -EUCLEAN to the caller;
4) As this is an unexpected scenario, that should never happen, mark the
check as unlikely, allowing the compiler to potentially generate better
code.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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At btrfs_cow_block() we have these checks to verify we are not using a
stale transaction (a past transaction with an unblocked state or higher),
and the only thing we do is to trigger a WARN with a message and a stack
trace. This however is a critical problem, highly unexpected and if it
happens it's most likely due to a bug, so we should error out and turn the
fs into error state so that such issue is much more easily noticed if it's
triggered.
The problem is critical because using such stale transaction will lead to
not persisting the extent buffer used for the COW operation, as allocating
a tree block adds the range of the respective extent buffer to the
->dirty_pages iotree of the transaction, and a stale transaction, in the
unlocked state or higher, will not flush dirty extent buffers anymore,
therefore resulting in not persisting the tree block and resource leaks
(not cleaning the dirty_pages iotree for example).
So do the following changes:
1) Return -EUCLEAN if we find a stale transaction;
2) Turn the fs into error state, with error -EUCLEAN, so that no
transaction can be committed, and generate a stack trace;
3) Combine both conditions into a single if statement, as both are related
and have the same error message;
4) Mark the check as unlikely, since this is not expected to ever happen.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Commit b7af0635c87f ("btrfs: print transaction aborted messages with an
error level") changed the log level of transaction aborted messages from
a debug level to an error level, so that such messages are always visible
even on production systems where the log level is normally above the debug
level (and also on some syzbot reports).
Later, commit fccf0c842ed4 ("btrfs: move btrfs_abort_transaction to
transaction.c") changed the log level back to debug level when the error
number for a transaction abort should not have a stack trace printed.
This happened for absolutely no reason. It's always useful to print
transaction abort messages with an error level, regardless of whether
the error number should cause a stack trace or not.
So change back the log level to error level.
Fixes: fccf0c842ed4 ("btrfs: move btrfs_abort_transaction to transaction.c")
CC: stable@vger.kernel.org # 6.5+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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[BUG]
The following script would allow invalid mount options to be specified
(although such invalid options would just be ignored):
# mkfs.btrfs -f $dev
# mount $dev $mnt1 <<< Successful mount expected
# mount $dev $mnt2 -o junk <<< Failed mount expected
# echo $?
0
[CAUSE]
For the 2nd mount, since the fs is already mounted, we won't go through
open_ctree() thus no btrfs_parse_options(), but only through
btrfs_parse_subvol_options().
However we do not treat unrecognized options from valid but irrelevant
options, thus those invalid options would just be ignored by
btrfs_parse_subvol_options().
[FIX]
Add the handling for Opt_err to handle invalid options and error out,
while still ignore other valid options inside btrfs_parse_subvol_options().
Reported-by: Anand Jain <anand.jain@oracle.com>
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Jens reported the following warnings from -Wmaybe-uninitialized recent
Linus' branch.
In file included from ./include/asm-generic/rwonce.h:26,
from ./arch/arm64/include/asm/rwonce.h:71,
from ./include/linux/compiler.h:246,
from ./include/linux/export.h:5,
from ./include/linux/linkage.h:7,
from ./include/linux/kernel.h:17,
from fs/btrfs/ioctl.c:6:
In function ‘instrument_copy_from_user_before’,
inlined from ‘_copy_from_user’ at ./include/linux/uaccess.h:148:3,
inlined from ‘copy_from_user’ at ./include/linux/uaccess.h:183:7,
inlined from ‘btrfs_ioctl_space_info’ at fs/btrfs/ioctl.c:2999:6,
inlined from ‘btrfs_ioctl’ at fs/btrfs/ioctl.c:4616:10:
./include/linux/kasan-checks.h:38:27: warning: ‘space_args’ may be used
uninitialized [-Wmaybe-uninitialized]
38 | #define kasan_check_write __kasan_check_write
./include/linux/instrumented.h:129:9: note: in expansion of macro
‘kasan_check_write’
129 | kasan_check_write(to, n);
| ^~~~~~~~~~~~~~~~~
./include/linux/kasan-checks.h: In function ‘btrfs_ioctl’:
./include/linux/kasan-checks.h:20:6: note: by argument 1 of type ‘const
volatile void *’ to ‘__kasan_check_write’ declared here
20 | bool __kasan_check_write(const volatile void *p, unsigned int
size);
| ^~~~~~~~~~~~~~~~~~~
fs/btrfs/ioctl.c:2981:39: note: ‘space_args’ declared here
2981 | struct btrfs_ioctl_space_args space_args;
| ^~~~~~~~~~
In function ‘instrument_copy_from_user_before’,
inlined from ‘_copy_from_user’ at ./include/linux/uaccess.h:148:3,
inlined from ‘copy_from_user’ at ./include/linux/uaccess.h:183:7,
inlined from ‘_btrfs_ioctl_send’ at fs/btrfs/ioctl.c:4343:9,
inlined from ‘btrfs_ioctl’ at fs/btrfs/ioctl.c:4658:10:
./include/linux/kasan-checks.h:38:27: warning: ‘args32’ may be used
uninitialized [-Wmaybe-uninitialized]
38 | #define kasan_check_write __kasan_check_write
./include/linux/instrumented.h:129:9: note: in expansion of macro
‘kasan_check_write’
129 | kasan_check_write(to, n);
| ^~~~~~~~~~~~~~~~~
./include/linux/kasan-checks.h: In function ‘btrfs_ioctl’:
./include/linux/kasan-checks.h:20:6: note: by argument 1 of type ‘const
volatile void *’ to ‘__kasan_check_write’ declared here
20 | bool __kasan_check_write(const volatile void *p, unsigned int
size);
| ^~~~~~~~~~~~~~~~~~~
fs/btrfs/ioctl.c:4341:49: note: ‘args32’ declared here
4341 | struct btrfs_ioctl_send_args_32 args32;
| ^~~~~~
This was due to his config options and having KASAN turned on,
which adds some extra checks around copy_from_user(), which then
triggered the -Wmaybe-uninitialized checker for these cases.
Fix the warnings by initializing the different structs we're copying
into.
Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- delayed refs fixes:
- fix race when refilling delayed refs block reserve
- prevent transaction block reserve underflow when starting
transaction
- error message and value adjustments
- fix build warnings with CONFIG_CC_OPTIMIZE_FOR_SIZE and
-Wmaybe-uninitialized
- fix for smatch report where uninitialized data from invalid extent
buffer range could be returned to the caller
- fix numeric overflow in statfs when calculating lower threshold
for a full filesystem
* tag 'for-6.6-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: initialize start_slot in btrfs_log_prealloc_extents
btrfs: make sure to initialize start and len in find_free_dev_extent
btrfs: reset destination buffer when read_extent_buffer() gets invalid range
btrfs: properly report 0 avail for very full file systems
btrfs: log message if extent item not found when running delayed extent op
btrfs: remove redundant BUG_ON() from __btrfs_inc_extent_ref()
btrfs: return -EUCLEAN for delayed tree ref with a ref count not equals to 1
btrfs: prevent transaction block reserve underflow when starting transaction
btrfs: fix race when refilling delayed refs block reserve
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull finegrained timestamp reverts from Christian Brauner:
"Earlier this week we sent a few minor fixes for the multi-grained
timestamp work in [1]. While we were polishing those up after Linus
realized that there might be a nicer way to fix them we received a
regression report in [2] that fine grained timestamps break gnulib
tests and thus possibly other tools.
The kernel will elide fine-grain timestamp updates when no one is
actively querying for them to avoid performance impacts. So a sequence
like write(f1) stat(f2) write(f2) stat(f2) write(f1) stat(f1) may
result in timestamp f1 to be older than the final f2 timestamp even
though f1 was last written too but the second write didn't update the
timestamp.
Such plotholes can lead to subtle bugs when programs compare
timestamps. For example, the nap() function in [2] will estimate that
it needs to wait one ns on a fine-grain timestamp enabled filesytem
between subsequent calls to observe a timestamp change. But in general
we don't update timestamps with more than one jiffie if we think that
no one is actively querying for fine-grain timestamps to avoid
performance impacts.
While discussing various fixes the decision was to go back to the
drawing board and ultimately to explore a solution that involves only
exposing such fine-grained timestamps to nfs internally and never to
userspace.
As there are multiple solutions discussed the honest thing to do here
is not to fix this up or disable it but to cleanly revert. The general
infrastructure will probably come back but there is no reason to keep
this code in mainline.
The general changes to timestamp handling are valid and a good cleanup
that will stay. The revert is fully bisectable"
Link: https://lore.kernel.org/all/20230918-hirte-neuzugang-4c2324e7bae3@brauner [1]
Link: https://lore.kernel.org/all/bf0524debb976627693e12ad23690094e4514303.camel@linuxfromscratch.org [2]
* tag 'v6.6-rc3.vfs.ctime.revert' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
Revert "fs: add infrastructure for multigrain timestamps"
Revert "btrfs: convert to multigrain timestamps"
Revert "ext4: switch to multigrain timestamps"
Revert "xfs: switch to multigrain timestamps"
Revert "tmpfs: add support for multigrain timestamps"
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Jens reported a compiler warning when using
CONFIG_CC_OPTIMIZE_FOR_SIZE=y that looks like this
fs/btrfs/tree-log.c: In function ‘btrfs_log_prealloc_extents’:
fs/btrfs/tree-log.c:4828:23: warning: ‘start_slot’ may be used
uninitialized [-Wmaybe-uninitialized]
4828 | ret = copy_items(trans, inode, dst_path, path,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
4829 | start_slot, ins_nr, 1, 0);
| ~~~~~~~~~~~~~~~~~~~~~~~~~
fs/btrfs/tree-log.c:4725:13: note: ‘start_slot’ was declared here
4725 | int start_slot;
| ^~~~~~~~~~
The compiler is incorrect, as we only use this code when ins_len > 0,
and when ins_len > 0 we have start_slot properly initialized. However
we generally find the -Wmaybe-uninitialized warnings valuable, so
initialize start_slot to get rid of the warning.
Reported-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Jens reported a compiler error when using CONFIG_CC_OPTIMIZE_FOR_SIZE=y
that looks like this
In function ‘gather_device_info’,
inlined from ‘btrfs_create_chunk’ at fs/btrfs/volumes.c:5507:8:
fs/btrfs/volumes.c:5245:48: warning: ‘dev_offset’ may be used uninitialized [-Wmaybe-uninitialized]
5245 | devices_info[ndevs].dev_offset = dev_offset;
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
fs/btrfs/volumes.c: In function ‘btrfs_create_chunk’:
fs/btrfs/volumes.c:5196:13: note: ‘dev_offset’ was declared here
5196 | u64 dev_offset;
This occurs because find_free_dev_extent is responsible for setting
dev_offset, however if we get an -ENOMEM at the top of the function
we'll return without setting the value.
This isn't actually a problem because we will see the -ENOMEM in
gather_device_info() and return and not use the uninitialized value,
however we also just don't want the compiler warning so rework the code
slightly in find_free_dev_extent() to make sure it's always setting
*start and *len to avoid the compiler warning.
Reported-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Commit f98b6215d7d1 ("btrfs: extent_io: do extra check for extent buffer
read write functions") changed how we handle invalid extent buffer range
for read_extent_buffer().
Previously if the range is invalid we just set the destination to zero,
but after the patch we do nothing and error out.
This can lead to smatch static checker errors like:
fs/btrfs/print-tree.c:186 print_uuid_item() error: uninitialized symbol 'subvol_id'.
fs/btrfs/tests/extent-io-tests.c:338 check_eb_bitmap() error: uninitialized symbol 'has'.
fs/btrfs/tests/extent-io-tests.c:353 check_eb_bitmap() error: uninitialized symbol 'has'.
fs/btrfs/uuid-tree.c:203 btrfs_uuid_tree_remove() error: uninitialized symbol 'read_subid'.
fs/btrfs/uuid-tree.c:353 btrfs_uuid_tree_iterate() error: uninitialized symbol 'subid_le'.
fs/btrfs/uuid-tree.c:72 btrfs_uuid_tree_lookup() error: uninitialized symbol 'data'.
fs/btrfs/volumes.c:7415 btrfs_dev_stats_value() error: uninitialized symbol 'val'.
Fix those warnings by reverting back to the old memset() behavior.
By this we keep the static checker happy and would still make a lot of
noise when such invalid ranges are passed in.
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Fixes: f98b6215d7d1 ("btrfs: extent_io: do extra check for extent buffer read write functions")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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A user reported some issues with smaller file systems that get very
full. While investigating this issue I noticed that df wasn't showing
100% full, despite having 0 chunk space and having < 1MiB of available
metadata space.
This turns out to be an overflow issue, we're doing:
total_available_metadata_space - SZ_4M < global_block_rsv_size
to determine if there's not enough space to make metadata allocations,
which overflows if total_available_metadata_space is < 4M. Fix this by
checking to see if our available space is greater than the 4M threshold.
This makes df properly report 100% usage on the file system.
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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When running a delayed extent operation, if we don't find the extent item
in the extent tree we just return -EIO without any logged message. This
indicates some bug or possibly a memory or fs corruption, so the return
value should not be -EIO but -EUCLEAN instead, and since it's not expected
to ever happen, print an informative error message so that if it happens
we have some idea of what went wrong, where to look at.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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At __btrfs_inc_extent_ref() we are doing a BUG_ON() if we are dealing with
a tree block reference that has a reference count that is different from 1,
but we have already dealt with this case at run_delayed_tree_ref(), making
it useless. So remove the BUG_ON().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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When running a delayed tree reference, if we find a ref count different
from 1, we return -EIO. This isn't an IO error, as it indicates either a
bug in the delayed refs code or a memory corruption, so change the error
code from -EIO to -EUCLEAN. Also tag the branch as 'unlikely' as this is
not expected to ever happen, and change the error message to print the
tree block's bytenr without the parenthesis (and there was a missing space
between the 'block' word and the opening parenthesis), for consistency as
that's the style we used everywhere else.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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When starting a transaction, with a non-zero number of items, we reserve
metadata space for that number of items and for delayed refs by doing a
call to btrfs_block_rsv_add(), with the transaction block reserve passed
as the block reserve argument. This reserves metadata space and adds it
to the transaction block reserve. Later we migrate the space we reserved
for delayed references from the transaction block reserve into the delayed
refs block reserve, by calling btrfs_migrate_to_delayed_refs_rsv().
btrfs_migrate_to_delayed_refs_rsv() decrements the number of bytes to
migrate from the source block reserve, and this however may result in an
underflow in case the space added to the transaction block reserve ended
up being used by another task that has not reserved enough space for its
own use - examples are tasks doing reflinks or hole punching because they
end up calling btrfs_replace_file_extents() -> btrfs_drop_extents() and
may need to modify/COW a variable number of leaves/paths, so they keep
trying to use space from the transaction block reserve when they need to
COW an extent buffer, and may end up trying to use more space then they
have reserved (1 unit/path only for removing file extent items).
This can be avoided by simply reserving space first without adding it to
the transaction block reserve, then add the space for delayed refs to the
delayed refs block reserve and finally add the remaining reserved space
to the transaction block reserve. This also makes the code a bit shorter
and simpler. So just do that.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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If we have two (or more) tasks attempting to refill the delayed refs block
reserve we can end up with the delayed block reserve being over reserved,
that is, with a reserved space greater than its size. If this happens, we
are holding to more reserved space than necessary for a while.
The race happens like this:
1) The delayed refs block reserve has a size of 8M and a reserved space of
6M for example;
2) Task A calls btrfs_delayed_refs_rsv_refill();
3) Task B also calls btrfs_delayed_refs_rsv_refill();
4) Task A sees there's a 2M difference between the size and the reserved
space of the delayed refs rsv, so it will reserve 2M of space by
calling btrfs_reserve_metadata_bytes();
5) Task B also sees that 2M difference, and like task A, it reserves
another 2M of metadata space;
6) Both task A and task B increase the reserved space of block reserve
by 2M, by calling btrfs_block_rsv_add_bytes(), so the block reserve
ends up with a size of 8M and a reserved space of 10M;
7) The extra, over reserved space will eventually be freed by some task
calling btrfs_delayed_refs_rsv_release() -> btrfs_block_rsv_release()
-> block_rsv_release_bytes(), as there we will detect the over reserve
and release that space.
So fix this by checking if we still need to add space to the delayed refs
block reserve after reserving the metadata space, and if we don't, just
release that space immediately.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"A few more followup fixes to the directory listing.
People have noticed different behaviour compared to other filesystems
after changes in 6.5. This is now unified to more "logical" and
expected behaviour while still within POSIX. And a few more fixes for
stable.
- change behaviour of readdir()/rewinddir() when new directory
entries are created after opendir(), properly tracking the last
entry
- fix race in readdir when multiple threads can set the last entry
index for a directory
Additionally:
- use exclusive lock when direct io might need to drop privs and call
notify_change()
- don't clear uptodate bit on page after an error, this may lead to a
deadlock in subpage mode
- fix waiting pattern when multiple readers block on Merkle tree
data, switch to folios"
* tag 'for-6.6-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix race between reading a directory and adding entries to it
btrfs: refresh dir last index during a rewinddir(3) call
btrfs: set last dir index to the current last index when opening dir
btrfs: don't clear uptodate on write errors
btrfs: file_remove_privs needs an exclusive lock in direct io write
btrfs: convert btrfs_read_merkle_tree_page() to use a folio
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This reverts commit 50e9ceef1d4f644ee0049e82e360058a64ec284c.
Users reported regressions due to enabling multi-grained timestamps
unconditionally. As no clear consensus on a solution has come up and the
discussion has gone back to the drawing board revert the infrastructure
changes for. If it isn't code that's here to stay, make it go away.
Message-ID: <20230920-keine-eile-c9755b5825db@brauner>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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When opening a directory (opendir(3)) or rewinding it (rewinddir(3)), we
are not holding the directory's inode locked, and this can result in later
attempting to add two entries to the directory with the same index number,
resulting in a transaction abort, with -EEXIST (-17), when inserting the
second delayed dir index. This results in a trace like the following:
Sep 11 22:34:59 myhostname kernel: BTRFS error (device dm-3): err add delayed dir index item(name: cockroach-stderr.log) into the insertion tree of the delayed node(root id: 5, inode id: 4539217, errno: -17)
Sep 11 22:34:59 myhostname kernel: ------------[ cut here ]------------
Sep 11 22:34:59 myhostname kernel: kernel BUG at fs/btrfs/delayed-inode.c:1504!
Sep 11 22:34:59 myhostname kernel: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
Sep 11 22:34:59 myhostname kernel: CPU: 0 PID: 7159 Comm: cockroach Not tainted 6.4.15-200.fc38.x86_64 #1
Sep 11 22:34:59 myhostname kernel: Hardware name: ASUS ESC500 G3/P9D WS, BIOS 2402 06/27/2018
Sep 11 22:34:59 myhostname kernel: RIP: 0010:btrfs_insert_delayed_dir_index+0x1da/0x260
Sep 11 22:34:59 myhostname kernel: Code: eb dd 48 (...)
Sep 11 22:34:59 myhostname kernel: RSP: 0000:ffffa9980e0fbb28 EFLAGS: 00010282
Sep 11 22:34:59 myhostname kernel: RAX: 0000000000000000 RBX: ffff8b10b8f4a3c0 RCX: 0000000000000000
Sep 11 22:34:59 myhostname kernel: RDX: 0000000000000000 RSI: ffff8b177ec21540 RDI: ffff8b177ec21540
Sep 11 22:34:59 myhostname kernel: RBP: ffff8b110cf80888 R08: 0000000000000000 R09: ffffa9980e0fb938
Sep 11 22:34:59 myhostname kernel: R10: 0000000000000003 R11: ffffffff86146508 R12: 0000000000000014
Sep 11 22:34:59 myhostname kernel: R13: ffff8b1131ae5b40 R14: ffff8b10b8f4a418 R15: 00000000ffffffef
Sep 11 22:34:59 myhostname kernel: FS: 00007fb14a7fe6c0(0000) GS:ffff8b177ec00000(0000) knlGS:0000000000000000
Sep 11 22:34:59 myhostname kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Sep 11 22:34:59 myhostname kernel: CR2: 000000c00143d000 CR3: 00000001b3b4e002 CR4: 00000000001706f0
Sep 11 22:34:59 myhostname kernel: Call Trace:
Sep 11 22:34:59 myhostname kernel: <TASK>
Sep 11 22:34:59 myhostname kernel: ? die+0x36/0x90
Sep 11 22:34:59 myhostname kernel: ? do_trap+0xda/0x100
Sep 11 22:34:59 myhostname kernel: ? btrfs_insert_delayed_dir_index+0x1da/0x260
Sep 11 22:34:59 myhostname kernel: ? do_error_trap+0x6a/0x90
Sep 11 22:34:59 myhostname kernel: ? btrfs_insert_delayed_dir_index+0x1da/0x260
Sep 11 22:34:59 myhostname kernel: ? exc_invalid_op+0x50/0x70
Sep 11 22:34:59 myhostname kernel: ? btrfs_insert_delayed_dir_index+0x1da/0x260
Sep 11 22:34:59 myhostname kernel: ? asm_exc_invalid_op+0x1a/0x20
Sep 11 22:34:59 myhostname kernel: ? btrfs_insert_delayed_dir_index+0x1da/0x260
Sep 11 22:34:59 myhostname kernel: ? btrfs_insert_delayed_dir_index+0x1da/0x260
Sep 11 22:34:59 myhostname kernel: btrfs_insert_dir_item+0x200/0x280
Sep 11 22:34:59 myhostname kernel: btrfs_add_link+0xab/0x4f0
Sep 11 22:34:59 myhostname kernel: ? ktime_get_real_ts64+0x47/0xe0
Sep 11 22:34:59 myhostname kernel: btrfs_create_new_inode+0x7cd/0xa80
Sep 11 22:34:59 myhostname kernel: btrfs_symlink+0x190/0x4d0
Sep 11 22:34:59 myhostname kernel: ? schedule+0x5e/0xd0
Sep 11 22:34:59 myhostname kernel: ? __d_lookup+0x7e/0xc0
Sep 11 22:34:59 myhostname kernel: vfs_symlink+0x148/0x1e0
Sep 11 22:34:59 myhostname kernel: do_symlinkat+0x130/0x140
Sep 11 22:34:59 myhostname kernel: __x64_sys_symlinkat+0x3d/0x50
Sep 11 22:34:59 myhostname kernel: do_syscall_64+0x5d/0x90
Sep 11 22:34:59 myhostname kernel: ? syscall_exit_to_user_mode+0x2b/0x40
Sep 11 22:34:59 myhostname kernel: ? do_syscall_64+0x6c/0x90
Sep 11 22:34:59 myhostname kernel: entry_SYSCALL_64_after_hwframe+0x72/0xdc
The race leading to the problem happens like this:
1) Directory inode X is loaded into memory, its ->index_cnt field is
initialized to (u64)-1 (at btrfs_alloc_inode());
2) Task A is adding a new file to directory X, holding its vfs inode lock,
and calls btrfs_set_inode_index() to get an index number for the entry.
Because the inode's index_cnt field is set to (u64)-1 it calls
btrfs_inode_delayed_dir_index_count() which fails because no dir index
entries were added yet to the delayed inode and then it calls
btrfs_set_inode_index_count(). This functions finds the last dir index
key and then sets index_cnt to that index value + 1. It found that the
last index key has an offset of 100. However before it assigns a value
of 101 to index_cnt...
3) Task B calls opendir(3), ending up at btrfs_opendir(), where the VFS
lock for inode X is not taken, so it calls btrfs_get_dir_last_index()
and sees index_cnt still with a value of (u64)-1. Because of that it
calls btrfs_inode_delayed_dir_index_count() which fails since no dir
index entries were added to the delayed inode yet, and then it also
calls btrfs_set_inode_index_count(). This also finds that the last
index key has an offset of 100, and before it assigns the value 101
to the index_cnt field of inode X...
4) Task A assigns a value of 101 to index_cnt. And then the code flow
goes to btrfs_set_inode_index() where it increments index_cnt from
101 to 102. Task A then creates a delayed dir index entry with a
sequence number of 101 and adds it to the delayed inode;
5) Task B assigns 101 to the index_cnt field of inode X;
6) At some later point when someone tries to add a new entry to the
directory, btrfs_set_inode_index() will return 101 again and shortly
after an attempt to add another delayed dir index key with index
number 101 will fail with -EEXIST resulting in a transaction abort.
Fix this by locking the inode at btrfs_get_dir_last_index(), which is only
only used when opening a directory or attempting to lseek on it.
Reported-by: ken <ken@bllue.org>
Link: https://lore.kernel.org/linux-btrfs/CAE6xmH+Lp=Q=E61bU+v9eWX8gYfLvu6jLYxjxjFpo3zHVPR0EQ@mail.gmail.com/
Reported-by: syzbot+d13490c82ad5353c779d@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/00000000000036e1290603e097e0@google.com/
Fixes: 9b378f6ad48c ("btrfs: fix infinite directory reads")
CC: stable@vger.kernel.org # 6.5+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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When opening a directory we find what's the index of its last entry and
then store it in the directory's file handle private data (struct
btrfs_file_private::last_index), so that in the case new directory entries
are added to a directory after an opendir(3) call we don't end up in an
infinite loop (see commit 9b378f6ad48c ("btrfs: fix infinite directory
reads")) when calling readdir(3).
However once rewinddir(3) is called, POSIX states [1] that any new
directory entries added after the previous opendir(3) call, must be
returned by subsequent calls to readdir(3):
"The rewinddir() function shall reset the position of the directory
stream to which dirp refers to the beginning of the directory.
It shall also cause the directory stream to refer to the current
state of the corresponding directory, as a call to opendir() would
have done."
We currently don't refresh the last_index field of the struct
btrfs_file_private associated to the directory, so after a rewinddir(3)
we are not returning any new entries added after the opendir(3) call.
Fix this by finding the current last index of the directory when llseek
is called against the directory.
This can be reproduced by the following C program provided by Ian Johnson:
#include <dirent.h>
#include <stdio.h>
int main(void) {
DIR *dir = opendir("test");
FILE *file;
file = fopen("test/1", "w");
fwrite("1", 1, 1, file);
fclose(file);
file = fopen("test/2", "w");
fwrite("2", 1, 1, file);
fclose(file);
rewinddir(dir);
struct dirent *entry;
while ((entry = readdir(dir))) {
printf("%s\n", entry->d_name);
}
closedir(dir);
return 0;
}
Reported-by: Ian Johnson <ian@ianjohnson.dev>
Link: https://lore.kernel.org/linux-btrfs/YR1P0S.NGASEG570GJ8@ianjohnson.dev/
Fixes: 9b378f6ad48c ("btrfs: fix infinite directory reads")
CC: stable@vger.kernel.org # 6.5+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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When opening a directory for reading it, we set the last index where we
stop iteration to the value in struct btrfs_inode::index_cnt. That value
does not match the index of the most recently added directory entry but
it's instead the index number that will be assigned the next directory
entry.
This means that if after the call to opendir(3) new directory entries are
added, a readdir(3) call will return the first new directory entry. This
is fine because POSIX says the following [1]:
"If a file is removed from or added to the directory after the most
recent call to opendir() or rewinddir(), whether a subsequent call to
readdir() returns an entry for that file is unspecified."
For example for the test script from commit 9b378f6ad48c ("btrfs: fix
infinite directory reads"), where we have 2000 files in a directory, ext4
doesn't return any new directory entry after opendir(3), while xfs returns
the first 13 new directory entries added after the opendir(3) call.
If we move to a shorter example with an empty directory when opendir(3) is
called, and 2 files added to the directory after the opendir(3) call, then
readdir(3) on btrfs will return the first file, ext4 and xfs return the 2
files (but in a different order). A test program for this, reported by
Ian Johnson, is the following:
#include <dirent.h>
#include <stdio.h>
int main(void) {
DIR *dir = opendir("test");
FILE *file;
file = fopen("test/1", "w");
fwrite("1", 1, 1, file);
fclose(file);
file = fopen("test/2", "w");
fwrite("2", 1, 1, file);
fclose(file);
struct dirent *entry;
while ((entry = readdir(dir))) {
printf("%s\n", entry->d_name);
}
closedir(dir);
return 0;
}
To make this less odd, change the behaviour to never return new entries
that were added after the opendir(3) call. This is done by setting the
last_index field of the struct btrfs_file_private attached to the
directory's file handle with a value matching btrfs_inode::index_cnt
minus 1, since that value always matches the index of the next new
directory entry and not the index of the most recently added entry.
[1] https://pubs.opengroup.org/onlinepubs/007904875/functions/readdir_r.html
Link: https://lore.kernel.org/linux-btrfs/YR1P0S.NGASEG570GJ8@ianjohnson.dev/
CC: stable@vger.kernel.org # 6.5+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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We have been consistently seeing hangs with generic/648 in our subpage
GitHub CI setup. This is a classic deadlock, we are calling
btrfs_read_folio() on a folio, which requires holding the folio lock on
the folio, and then finding a ordered extent that overlaps that range
and calling btrfs_start_ordered_extent(), which then tries to write out
the dirty page, which requires taking the folio lock and then we
deadlock.
The hang happens because we're writing to range [1271750656, 1271767040),
page index [77621, 77622], and page 77621 is !Uptodate. It is also Dirty,
so we call btrfs_read_folio() for 77621 and which does
btrfs_lock_and_flush_ordered_range() for that range, and we find an ordered
extent which is [1271644160, 1271746560), page index [77615, 77621].
The page indexes overlap, but the actual bytes don't overlap. We're
holding the page lock for 77621, then call
btrfs_lock_and_flush_ordered_range() which tries to flush the dirty
page, and tries to lock 77621 again and then we deadlock.
The byte ranges do not overlap, but with subpage support if we clear
uptodate on any portion of the page we mark the entire thing as not
uptodate.
We have been clearing page uptodate on write errors, but no other file
system does this, and is in fact incorrect. This doesn't hurt us in the
!subpage case because we can't end up with overlapped ranges that don't
also overlap on the page.
Fix this by not clearing uptodate when we have a write error. The only
thing we should be doing in this case is setting the mapping error and
carrying on. This makes it so we would no longer call
btrfs_read_folio() on the page as it's uptodate and eliminates the
deadlock.
With this patch we're now able to make it through a full fstests run on
our subpage blocksize VMs.
Note for stable backports: this probably goes beyond 6.1 but the code
has been cleaned up and clearing the uptodate bit must be verified on
each version independently.
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This was noticed by Miklos that file_remove_privs might call into
notify_change(), which requires to hold an exclusive lock. The problem
exists in FUSE and btrfs. We can fix it without any additional helpers
from VFS, in case the privileges would need to be dropped, change the
lock type to be exclusive and redo the loop.
Fixes: e9adabb9712e ("btrfs: use shared lock for direct writes within EOF")
CC: Miklos Szeredi <miklos@szeredi.hu>
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Remove a number of hidden calls to compound_head() by using a folio
throughout. Also follow core kernel coding style by adding the folio to
the page cache immediately after allocation instead of doing the read
first, then adding it to the page cache. This ordering makes subsequent
readers block waiting for the first reader instead of duplicating the
work only to throw it away when they find out they lost the race.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: David Sterba <dsterba@suse.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- several fixes for handling directory item (inserting, removing,
iteration, error handling)
- fix transaction commit stalls when auto relocation is running and
blocks other tasks that want to commit
- fix a build error when DEBUG is enabled
- fix lockdep warning in inode number lookup ioctl
- fix race when finishing block group creation
- remove link to obsolete wiki in several files
* tag 'for-6.6-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
MAINTAINERS: remove links to obsolete btrfs.wiki.kernel.org
btrfs: assert delayed node locked when removing delayed item
btrfs: remove BUG() after failure to insert delayed dir index item
btrfs: improve error message after failure to add delayed dir index item
btrfs: fix a compilation error if DEBUG is defined in btree_dirty_folio
btrfs: check for BTRFS_FS_ERROR in pending ordered assert
btrfs: fix lockdep splat and potential deadlock after failure running delayed items
btrfs: do not block starts waiting on previous transaction commit
btrfs: release path before inode lookup during the ino lookup ioctl
btrfs: fix race between finishing block group creation and its item update
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The wiki has been archived and is not updated anymore. Remove or replace
the links in files that contain it (MAINTAINERS, Kconfig, docs).
Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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When removing a delayed item, or releasing which will remove it as well,
we will modify one of the delayed node's rbtrees and item counter if the
delayed item is in one of the rbtrees. This require having the delayed
node's mutex locked, otherwise we will race with other tasks modifying
the rbtrees and the counter.
This is motivated by a previous version of another patch actually calling
btrfs_release_delayed_item() after unlocking the delayed node's mutex and
against a delayed item that is in a rbtree.
So assert at __btrfs_remove_delayed_item() that the delayed node's mutex
is locked.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Instead of calling BUG() when we fail to insert a delayed dir index item
into the delayed node's tree, we can just release all the resources we
have allocated/acquired before and return the error to the caller. This is
fine because all existing call chains undo anything they have done before
calling btrfs_insert_delayed_dir_index() or BUG_ON (when creating pending
snapshots in the transaction commit path).
So remove the BUG() call and do proper error handling.
This relates to a syzbot report linked below, but does not fix it because
it only prevents hitting a BUG(), it does not fix the issue where somehow
we attempt to use twice the same index number for different index items.
Link: https://lore.kernel.org/linux-btrfs/00000000000036e1290603e097e0@google.com/
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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If we fail to add a delayed dir index item because there's already another
item with the same index number, we print an error message (and then BUG).
However that message isn't very helpful to debug anything because we don't
know what's the index number and what are the values of index counters in
the inode and its delayed inode (index_cnt fields of struct btrfs_inode
and struct btrfs_delayed_node).
So update the error message to include the index number and counters.
We actually had a recent case where this issue was hit by a syzbot report
(see the link below).
Link: https://lore.kernel.org/linux-btrfs/00000000000036e1290603e097e0@google.com/
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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[BUG]
After commit 72a69cd03082 ("btrfs: subpage: pack all subpage bitmaps
into a larger bitmap"), the DEBUG section of btree_dirty_folio() would
no longer compile.
[CAUSE]
If DEBUG is defined, we would do extra checks for btree_dirty_folio(),
mostly to make sure the range we marked dirty has an extent buffer and
that extent buffer is dirty.
For subpage, we need to iterate through all the extent buffers covered
by that page range, and make sure they all matches the criteria.
However commit 72a69cd03082 ("btrfs: subpage: pack all subpage bitmaps
into a larger bitmap") changes how we store the bitmap, we pack all the
16 bits bitmaps into a larger bitmap, which would save some space.
This means we no longer have btrfs_subpage::dirty_bitmap, instead the
dirty bitmap is starting at btrfs_subpage_info::dirty_offset, and has a
length of btrfs_subpage_info::bitmap_nr_bits.
[FIX]
Although I'm not sure if it still makes sense to maintain such code, at
least let it compile.
This patch would let us test the bits one by one through the bitmaps.
CC: stable@vger.kernel.org # 6.1+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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If we do fast tree logging we increment a counter on the current
transaction for every ordered extent we need to wait for. This means we
expect the transaction to still be there when we clear pending on the
ordered extent. However if we happen to abort the transaction and clean
it up, there could be no running transaction, and thus we'll trip the
"ASSERT(trans)" check. This is obviously incorrect, and the code
properly deals with the case that the transaction doesn't exist. Fix
this ASSERT() to only fire if there's no trans and we don't have
BTRFS_FS_ERROR() set on the file system.
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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delayed items
When running delayed items we are holding a delayed node's mutex and then
we will attempt to modify a subvolume btree to insert/update/delete the
delayed items. However if have an error during the insertions for example,
btrfs_insert_delayed_items() may return with a path that has locked extent
buffers (a leaf at the very least), and then we attempt to release the
delayed node at __btrfs_run_delayed_items(), which requires taking the
delayed node's mutex, causing an ABBA type of deadlock. This was reported
by syzbot and the lockdep splat is the following:
WARNING: possible circular locking dependency detected
6.5.0-rc7-syzkaller-00024-g93f5de5f648d #0 Not tainted
------------------------------------------------------
syz-executor.2/13257 is trying to acquire lock:
ffff88801835c0c0 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node+0x9a/0xaa0 fs/btrfs/delayed-inode.c:256
but task is already holding lock:
ffff88802a5ab8e8 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_lock+0x3c/0x2a0 fs/btrfs/locking.c:198
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (btrfs-tree-00){++++}-{3:3}:
__lock_release kernel/locking/lockdep.c:5475 [inline]
lock_release+0x36f/0x9d0 kernel/locking/lockdep.c:5781
up_write+0x79/0x580 kernel/locking/rwsem.c:1625
btrfs_tree_unlock_rw fs/btrfs/locking.h:189 [inline]
btrfs_unlock_up_safe+0x179/0x3b0 fs/btrfs/locking.c:239
search_leaf fs/btrfs/ctree.c:1986 [inline]
btrfs_search_slot+0x2511/0x2f80 fs/btrfs/ctree.c:2230
btrfs_insert_empty_items+0x9c/0x180 fs/btrfs/ctree.c:4376
btrfs_insert_delayed_item fs/btrfs/delayed-inode.c:746 [inline]
btrfs_insert_delayed_items fs/btrfs/delayed-inode.c:824 [inline]
__btrfs_commit_inode_delayed_items+0xd24/0x2410 fs/btrfs/delayed-inode.c:1111
__btrfs_run_delayed_items+0x1db/0x430 fs/btrfs/delayed-inode.c:1153
flush_space+0x269/0xe70 fs/btrfs/space-info.c:723
btrfs_async_reclaim_metadata_space+0x106/0x350 fs/btrfs/space-info.c:1078
process_one_work+0x92c/0x12c0 kernel/workqueue.c:2600
worker_thread+0xa63/0x1210 kernel/workqueue.c:2751
kthread+0x2b8/0x350 kernel/kthread.c:389
ret_from_fork+0x2e/0x60 arch/x86/kernel/process.c:145
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
-> #0 (&delayed_node->mutex){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3142 [inline]
check_prevs_add kernel/locking/lockdep.c:3261 [inline]
validate_chain kernel/locking/lockdep.c:3876 [inline]
__lock_acquire+0x39ff/0x7f70 kernel/locking/lockdep.c:5144
lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5761
__mutex_lock_common+0x1d8/0x2530 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:799
__btrfs_release_delayed_node+0x9a/0xaa0 fs/btrfs/delayed-inode.c:256
btrfs_release_delayed_node fs/btrfs/delayed-inode.c:281 [inline]
__btrfs_run_delayed_items+0x2b5/0x430 fs/btrfs/delayed-inode.c:1156
btrfs_commit_transaction+0x859/0x2ff0 fs/btrfs/transaction.c:2276
btrfs_sync_file+0xf56/0x1330 fs/btrfs/file.c:1988
vfs_fsync_range fs/sync.c:188 [inline]
vfs_fsync fs/sync.c:202 [inline]
do_fsync fs/sync.c:212 [inline]
__do_sys_fsync fs/sync.c:220 [inline]
__se_sys_fsync fs/sync.c:218 [inline]
__x64_sys_fsync+0x196/0x1e0 fs/sync.c:218
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(btrfs-tree-00);
lock(&delayed_node->mutex);
lock(btrfs-tree-00);
lock(&delayed_node->mutex);
*** DEADLOCK ***
3 locks held by syz-executor.2/13257:
#0: ffff88802c1ee370 (btrfs_trans_num_writers){++++}-{0:0}, at: spin_unlock include/linux/spinlock.h:391 [inline]
#0: ffff88802c1ee370 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0xb87/0xe00 fs/btrfs/transaction.c:287
#1: ffff88802c1ee398 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0xbb2/0xe00 fs/btrfs/transaction.c:288
#2: ffff88802a5ab8e8 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_lock+0x3c/0x2a0 fs/btrfs/locking.c:198
stack backtrace:
CPU: 0 PID: 13257 Comm: syz-executor.2 Not tainted 6.5.0-rc7-syzkaller-00024-g93f5de5f648d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
check_noncircular+0x375/0x4a0 kernel/locking/lockdep.c:2195
check_prev_add kernel/locking/lockdep.c:3142 [inline]
check_prevs_add kernel/locking/lockdep.c:3261 [inline]
validate_chain kernel/locking/lockdep.c:3876 [inline]
__lock_acquire+0x39ff/0x7f70 kernel/locking/lockdep.c:5144
lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5761
__mutex_lock_common+0x1d8/0x2530 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:799
__btrfs_release_delayed_node+0x9a/0xaa0 fs/btrfs/delayed-inode.c:256
btrfs_release_delayed_node fs/btrfs/delayed-inode.c:281 [inline]
__btrfs_run_delayed_items+0x2b5/0x430 fs/btrfs/delayed-inode.c:1156
btrfs_commit_transaction+0x859/0x2ff0 fs/btrfs/transaction.c:2276
btrfs_sync_file+0xf56/0x1330 fs/btrfs/file.c:1988
vfs_fsync_range fs/sync.c:188 [inline]
vfs_fsync fs/sync.c:202 [inline]
do_fsync fs/sync.c:212 [inline]
__do_sys_fsync fs/sync.c:220 [inline]
__se_sys_fsync fs/sync.c:218 [inline]
__x64_sys_fsync+0x196/0x1e0 fs/sync.c:218
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f3ad047cae9
Code: 28 00 00 00 75 (...)
RSP: 002b:00007f3ad12510c8 EFLAGS: 00000246 ORIG_RAX: 000000000000004a
RAX: ffffffffffffffda RBX: 00007f3ad059bf80 RCX: 00007f3ad047cae9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f3ad04c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f3ad059bf80 R15: 00007ffe56af92f8
</TASK>
------------[ cut here ]------------
Fix this by releasing the path before releasing the delayed node in the
error path at __btrfs_run_delayed_items().
Reported-by: syzbot+a379155f07c134ea9879@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/000000000000abba27060403b5bd@google.com/
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Internally I got a report of very long stalls on normal operations like
creating a new file when auto relocation was running. The reporter used
the 'bpf offcputime' tracer to show that we would get stuck in
start_transaction for 5 to 30 seconds, and were always being woken up by
the transaction commit.
Using my timing-everything script, which times how long a function takes
and what percentage of that total time is taken up by its children, I
saw several traces like this
1083 took 32812902424 ns
29929002926 ns 91.2110% wait_for_commit_duration
25568 ns 7.7920e-05% commit_fs_roots_duration
1007751 ns 0.00307% commit_cowonly_roots_duration
446855602 ns 1.36182% btrfs_run_delayed_refs_duration
271980 ns 0.00082% btrfs_run_delayed_items_duration
2008 ns 6.1195e-06% btrfs_apply_pending_changes_duration
9656 ns 2.9427e-05% switch_commit_roots_duration
1598 ns 4.8700e-06% btrfs_commit_device_sizes_duration
4314 ns 1.3147e-05% btrfs_free_log_root_tree_duration
Here I was only tracing functions that happen where we are between
START_COMMIT and UNBLOCKED in order to see what would be keeping us
blocked for so long. The wait_for_commit() we do is where we wait for a
previous transaction that hasn't completed it's commit. This can
include all of the unpin work and other cleanups, which tends to be the
longest part of our transaction commit.
There is no reason we should be blocking new things from entering the
transaction at this point, it just adds to random latency spikes for no
reason.
Fix this by adding a PREP stage. This allows us to properly deal with
multiple committers coming in at the same time, we retain the behavior
that the winner waits on the previous transaction and the losers all
wait for this transaction commit to occur. Nothing else is blocked
during the PREP stage, and then once the wait is complete we switch to
COMMIT_START and all of the same behavior as before is maintained.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
During the ino lookup ioctl we can end up calling btrfs_iget() to get an
inode reference while we are holding on a root's btree. If btrfs_iget()
needs to lookup the inode from the root's btree, because it's not
currently loaded in memory, then it will need to lock another or the
same path in the same root btree. This may result in a deadlock and
trigger the following lockdep splat:
WARNING: possible circular locking dependency detected
6.5.0-rc7-syzkaller-00004-gf7757129e3de #0 Not tainted
------------------------------------------------------
syz-executor277/5012 is trying to acquire lock:
ffff88802df41710 (btrfs-tree-01){++++}-{3:3}, at: __btrfs_tree_read_lock+0x2f/0x220 fs/btrfs/locking.c:136
but task is already holding lock:
ffff88802df418e8 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x2f/0x220 fs/btrfs/locking.c:136
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (btrfs-tree-00){++++}-{3:3}:
down_read_nested+0x49/0x2f0 kernel/locking/rwsem.c:1645
__btrfs_tree_read_lock+0x2f/0x220 fs/btrfs/locking.c:136
btrfs_search_slot+0x13a4/0x2f80 fs/btrfs/ctree.c:2302
btrfs_init_root_free_objectid+0x148/0x320 fs/btrfs/disk-io.c:4955
btrfs_init_fs_root fs/btrfs/disk-io.c:1128 [inline]
btrfs_get_root_ref+0x5ae/0xae0 fs/btrfs/disk-io.c:1338
btrfs_get_fs_root fs/btrfs/disk-io.c:1390 [inline]
open_ctree+0x29c8/0x3030 fs/btrfs/disk-io.c:3494
btrfs_fill_super+0x1c7/0x2f0 fs/btrfs/super.c:1154
btrfs_mount_root+0x7e0/0x910 fs/btrfs/super.c:1519
legacy_get_tree+0xef/0x190 fs/fs_context.c:611
vfs_get_tree+0x8c/0x270 fs/super.c:1519
fc_mount fs/namespace.c:1112 [inline]
vfs_kern_mount+0xbc/0x150 fs/namespace.c:1142
btrfs_mount+0x39f/0xb50 fs/btrfs/super.c:1579
legacy_get_tree+0xef/0x190 fs/fs_context.c:611
vfs_get_tree+0x8c/0x270 fs/super.c:1519
do_new_mount+0x28f/0xae0 fs/namespace.c:3335
do_mount fs/namespace.c:3675 [inline]
__do_sys_mount fs/namespace.c:3884 [inline]
__se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3861
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
-> #0 (btrfs-tree-01){++++}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3142 [inline]
check_prevs_add kernel/locking/lockdep.c:3261 [inline]
validate_chain kernel/locking/lockdep.c:3876 [inline]
__lock_acquire+0x39ff/0x7f70 kernel/locking/lockdep.c:5144
lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5761
down_read_nested+0x49/0x2f0 kernel/locking/rwsem.c:1645
__btrfs_tree_read_lock+0x2f/0x220 fs/btrfs/locking.c:136
btrfs_tree_read_lock fs/btrfs/locking.c:142 [inline]
btrfs_read_lock_root_node+0x292/0x3c0 fs/btrfs/locking.c:281
btrfs_search_slot_get_root fs/btrfs/ctree.c:1832 [inline]
btrfs_search_slot+0x4ff/0x2f80 fs/btrfs/ctree.c:2154
btrfs_lookup_inode+0xdc/0x480 fs/btrfs/inode-item.c:412
btrfs_read_locked_inode fs/btrfs/inode.c:3892 [inline]
btrfs_iget_path+0x2d9/0x1520 fs/btrfs/inode.c:5716
btrfs_search_path_in_tree_user fs/btrfs/ioctl.c:1961 [inline]
btrfs_ioctl_ino_lookup_user+0x77a/0xf50 fs/btrfs/ioctl.c:2105
btrfs_ioctl+0xb0b/0xd40 fs/btrfs/ioctl.c:4683
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xf8/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(btrfs-tree-00);
lock(btrfs-tree-01);
lock(btrfs-tree-00);
rlock(btrfs-tree-01);
*** DEADLOCK ***
1 lock held by syz-executor277/5012:
#0: ffff88802df418e8 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x2f/0x220 fs/btrfs/locking.c:136
stack backtrace:
CPU: 1 PID: 5012 Comm: syz-executor277 Not tainted 6.5.0-rc7-syzkaller-00004-gf7757129e3de #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
check_noncircular+0x375/0x4a0 kernel/locking/lockdep.c:2195
check_prev_add kernel/locking/lockdep.c:3142 [inline]
check_prevs_add kernel/locking/lockdep.c:3261 [inline]
validate_chain kernel/locking/lockdep.c:3876 [inline]
__lock_acquire+0x39ff/0x7f70 kernel/locking/lockdep.c:5144
lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5761
down_read_nested+0x49/0x2f0 kernel/locking/rwsem.c:1645
__btrfs_tree_read_lock+0x2f/0x220 fs/btrfs/locking.c:136
btrfs_tree_read_lock fs/btrfs/locking.c:142 [inline]
btrfs_read_lock_root_node+0x292/0x3c0 fs/btrfs/locking.c:281
btrfs_search_slot_get_root fs/btrfs/ctree.c:1832 [inline]
btrfs_search_slot+0x4ff/0x2f80 fs/btrfs/ctree.c:2154
btrfs_lookup_inode+0xdc/0x480 fs/btrfs/inode-item.c:412
btrfs_read_locked_inode fs/btrfs/inode.c:3892 [inline]
btrfs_iget_path+0x2d9/0x1520 fs/btrfs/inode.c:5716
btrfs_search_path_in_tree_user fs/btrfs/ioctl.c:1961 [inline]
btrfs_ioctl_ino_lookup_user+0x77a/0xf50 fs/btrfs/ioctl.c:2105
btrfs_ioctl+0xb0b/0xd40 fs/btrfs/ioctl.c:4683
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xf8/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f0bec94ea39
Fix this simply by releasing the path before calling btrfs_iget() as at
point we don't need the path anymore.
Reported-by: syzbot+bf66ad948981797d2f1d@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/00000000000045fa140603c4a969@google.com/
Fixes: 23d0b79dfaed ("btrfs: Add unprivileged version of ino_lookup ioctl")
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Commit 675dfe1223a6 ("btrfs: fix block group item corruption after
inserting new block group") fixed one race that resulted in not persisting
a block group's item when its "used" bytes field decreases to zero.
However there's another race that can happen in a much shorter time window
that results in the same problem. The following sequence of steps explains
how it can happen:
1) Task A creates a metadata block group X, its "used" and "commit_used"
fields are initialized to 0;
2) Two extents are allocated from block group X, so its "used" field is
updated to 32K, and its "commit_used" field remains as 0;
3) Transaction commit starts, by some task B, and it enters
btrfs_start_dirty_block_groups(). There it tries to update the block
group item for block group X, which currently has its "used" field with
a value of 32K and its "commit_used" field with a value of 0. However
that fails since the block group item was not yet inserted, so at
update_block_group_item(), the btrfs_search_slot() call returns 1, and
then we set 'ret' to -ENOENT. Before jumping to the label 'fail'...
4) The block group item is inserted by task A, when for example
btrfs_create_pending_block_groups() is called when releasing its
transaction handle. This results in insert_block_group_item() inserting
the block group item in the extent tree (or block group tree), with a
"used" field having a value of 32K and setting "commit_used", in struct
btrfs_block_group, to the same value (32K);
5) Task B jumps to the 'fail' label and then resets the "commit_used"
field to 0. At btrfs_start_dirty_block_groups(), because -ENOENT was
returned from update_block_group_item(), we add the block group again
to the list of dirty block groups, so that we will try again in the
critical section of the transaction commit when calling
btrfs_write_dirty_block_groups();
6) Later the two extents from block group X are freed, so its "used" field
becomes 0;
7) If no more extents are allocated from block group X before we get into
btrfs_write_dirty_block_groups(), then when we call
update_block_group_item() again for block group X, we will not update
the block group item to reflect that it has 0 bytes used, because the
"used" and "commit_used" fields in struct btrfs_block_group have the
same value, a value of 0.
As a result after committing the transaction we have an empty block
group with its block group item having a 32K value for its "used" field.
This will trigger errors from fsck ("btrfs check" command) and after
mounting again the fs, the cleaner kthread will not automatically delete
the empty block group, since its "used" field is not 0. Possibly there
are other issues due to this inconsistency.
When this issue happens, the error reported by fsck is like this:
[1/7] checking root items
[2/7] checking extents
block group [1104150528 1073741824] used 39796736 but extent items used 0
ERROR: errors found in extent allocation tree or chunk allocation
(...)
So fix this by not resetting the "commit_used" field of a block group when
we don't find the block group item at update_block_group_item().
Fixes: 7248e0cebbef ("btrfs: skip update of block group item if used bytes are the same")
CC: stable@vger.kernel.org # 6.2+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Some swap cleanups from Ma Wupeng ("fix WARN_ON in
add_to_avail_list")
- Peter Xu has a series (mm/gup: Unify hugetlb, speed up thp") which
reduces the special-case code for handling hugetlb pages in GUP. It
also speeds up GUP handling of transparent hugepages.
- Peng Zhang provides some maple tree speedups ("Optimize the fast path
of mas_store()").
- Sergey Senozhatsky has improved te performance of zsmalloc during
compaction (zsmalloc: small compaction improvements").
- Domenico Cerasuolo has developed additional selftest code for zswap
("selftests: cgroup: add zswap test program").
- xu xin has doe some work on KSM's handling of zero pages. These
changes are mainly to enable the user to better understand the
effectiveness of KSM's treatment of zero pages ("ksm: support
tracking KSM-placed zero-pages").
- Jeff Xu has fixes the behaviour of memfd's
MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED sysctl ("mm/memfd: fix sysctl
MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED").
- David Howells has fixed an fscache optimization ("mm, netfs, fscache:
Stop read optimisation when folio removed from pagecache").
- Axel Rasmussen has given userfaultfd the ability to simulate memory
poisoning ("add UFFDIO_POISON to simulate memory poisoning with
UFFD").
- Miaohe Lin has contributed some routine maintenance work on the
memory-failure code ("mm: memory-failure: remove unneeded PageHuge()
check").
- Peng Zhang has contributed some maintenance work on the maple tree
code ("Improve the validation for maple tree and some cleanup").
- Hugh Dickins has optimized the collapsing of shmem or file pages into
THPs ("mm: free retracted page table by RCU").
- Jiaqi Yan has a patch series which permits us to use the healthy
subpages within a hardware poisoned huge page for general purposes
("Improve hugetlbfs read on HWPOISON hugepages").
- Kemeng Shi has done some maintenance work on the pagetable-check code
("Remove unused parameters in page_table_check").
- More folioification work from Matthew Wilcox ("More filesystem folio
conversions for 6.6"), ("Followup folio conversions for zswap"). And
from ZhangPeng ("Convert several functions in page_io.c to use a
folio").
- page_ext cleanups from Kemeng Shi ("minor cleanups for page_ext").
- Baoquan He has converted some architectures to use the
GENERIC_IOREMAP ioremap()/iounmap() code ("mm: ioremap: Convert
architectures to take GENERIC_IOREMAP way").
- Anshuman Khandual has optimized arm64 tlb shootdown ("arm64: support
batched/deferred tlb shootdown during page reclamation/migration").
- Better maple tree lockdep checking from Liam Howlett ("More strict
maple tree lockdep"). Liam also developed some efficiency
improvements ("Reduce preallocations for maple tree").
- Cleanup and optimization to the secondary IOMMU TLB invalidation,
from Alistair Popple ("Invalidate secondary IOMMU TLB on permission
upgrade").
- Ryan Roberts fixes some arm64 MM selftest issues ("selftests/mm fixes
for arm64").
- Kemeng Shi provides some maintenance work on the compaction code
("Two minor cleanups for compaction").
- Some reduction in mmap_lock pressure from Matthew Wilcox ("Handle
most file-backed faults under the VMA lock").
- Aneesh Kumar contributes code to use the vmemmap optimization for DAX
on ppc64, under some circumstances ("Add support for DAX vmemmap
optimization for ppc64").
- page-ext cleanups from Kemeng Shi ("add page_ext_data to get client
data in page_ext"), ("minor cleanups to page_ext header").
- Some zswap cleanups from Johannes Weiner ("mm: zswap: three
cleanups").
- kmsan cleanups from ZhangPeng ("minor cleanups for kmsan").
- VMA handling cleanups from Kefeng Wang ("mm: convert to
vma_is_initial_heap/stack()").
- DAMON feature work from SeongJae Park ("mm/damon/sysfs-schemes:
implement DAMOS tried total bytes file"), ("Extend DAMOS filters for
address ranges and DAMON monitoring targets").
- Compaction work from Kemeng Shi ("Fixes and cleanups to compaction").
- Liam Howlett has improved the maple tree node replacement code
("maple_tree: Change replacement strategy").
- ZhangPeng has a general code cleanup - use the K() macro more widely
("cleanup with helper macro K()").
- Aneesh Kumar brings memmap-on-memory to ppc64 ("Add support for
memmap on memory feature on ppc64").
- pagealloc cleanups from Kemeng Shi ("Two minor cleanups for pcp list
in page_alloc"), ("Two minor cleanups for get pageblock
migratetype").
- Vishal Moola introduces a memory descriptor for page table tracking,
"struct ptdesc" ("Split ptdesc from struct page").
- memfd selftest maintenance work from Aleksa Sarai ("memfd: cleanups
for vm.memfd_noexec").
- MM include file rationalization from Hugh Dickins ("arch: include
asm/cacheflush.h in asm/hugetlb.h").
- THP debug output fixes from Hugh Dickins ("mm,thp: fix sloppy text
output").
- kmemleak improvements from Xiaolei Wang ("mm/kmemleak: use
object_cache instead of kmemleak_initialized").
- More folio-related cleanups from Matthew Wilcox ("Remove _folio_dtor
and _folio_order").
- A VMA locking scalability improvement from Suren Baghdasaryan
("Per-VMA lock support for swap and userfaults").
- pagetable handling cleanups from Matthew Wilcox ("New page table
range API").
- A batch of swap/thp cleanups from David Hildenbrand ("mm/swap: stop
using page->private on tail pages for THP_SWAP + cleanups").
- Cleanups and speedups to the hugetlb fault handling from Matthew
Wilcox ("Change calling convention for ->huge_fault").
- Matthew Wilcox has also done some maintenance work on the MM
subsystem documentation ("Improve mm documentation").
* tag 'mm-stable-2023-08-28-18-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (489 commits)
maple_tree: shrink struct maple_tree
maple_tree: clean up mas_wr_append()
secretmem: convert page_is_secretmem() to folio_is_secretmem()
nios2: fix flush_dcache_page() for usage from irq context
hugetlb: add documentation for vma_kernel_pagesize()
mm: add orphaned kernel-doc to the rst files.
mm: fix clean_record_shared_mapping_range kernel-doc
mm: fix get_mctgt_type() kernel-doc
mm: fix kernel-doc warning from tlb_flush_rmaps()
mm: remove enum page_entry_size
mm: allow ->huge_fault() to be called without the mmap_lock held
mm: move PMD_ORDER to pgtable.h
mm: remove checks for pte_index
memcg: remove duplication detection for mem_cgroup_uncharge_swap
mm/huge_memory: work on folio->swap instead of page->private when splitting folio
mm/swap: inline folio_set_swap_entry() and folio_swap_entry()
mm/swap: use dedicated entry for swap in folio
mm/swap: stop using page->private on tail pages for THP_SWAP
selftests/mm: fix WARNING comparing pointer to 0
selftests: cgroup: fix test_kmem_memcg_deletion kernel mem check
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"No new features, the bulk of the changes are fixes, refactoring and
cleanups. The notable fix is the scrub performance restoration after
rewrite in 6.4, though still only partial.
Fixes:
- scrub performance drop due to rewrite in 6.4 partially restored:
- do IO grouping by blg_plug/blk_unplug again
- avoid unnecessary tree searches when processing stripes, in
extent and checksum trees
- the drop is noticeable on fast PCIe devices, -66% and restored
to -33% of the original
- backports to 6.4 planned
- handle more corner cases of transaction commit during orphan
cleanup or delayed ref processing
- use correct fsid/metadata_uuid when validating super block
- copy directory permissions and time when creating a stub subvolume
Core:
- debugging feature integrity checker deprecated, to be removed in
6.7
- in zoned mode, zones are activated just before the write, making
error handling easier, now the overcommit mechanism can be enabled
again which improves performance by avoiding more frequent flushing
- v0 extent handling completely removed, deprecated long time ago
- error handling improvements
- tests:
- extent buffer bitmap tests
- pinned extent splitting tests
- cleanups and refactoring:
- compression writeback
- extent buffer bitmap
- space flushing, ENOSPC handling"
* tag 'for-6.6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (110 commits)
btrfs: zoned: skip splitting and logical rewriting on pre-alloc write
btrfs: tests: test invalid splitting when skipping pinned drop extent_map
btrfs: tests: add a test for btrfs_add_extent_mapping
btrfs: tests: add extent_map tests for dropping with odd layouts
btrfs: scrub: move write back of repaired sectors to scrub_stripe_read_repair_worker()
btrfs: scrub: don't go ordered workqueue for dev-replace
btrfs: scrub: fix grouping of read IO
btrfs: scrub: avoid unnecessary csum tree search preparing stripes
btrfs: scrub: avoid unnecessary extent tree search preparing stripes
btrfs: copy dir permission and time when creating a stub subvolume
btrfs: remove pointless empty list check when reading delayed dir indexes
btrfs: drop redundant check to use fs_devices::metadata_uuid
btrfs: compare the correct fsid/metadata_uuid in btrfs_validate_super
btrfs: use the correct superblock to compare fsid in btrfs_validate_super
btrfs: simplify memcpy either of metadata_uuid or fsid
btrfs: add a helper to read the superblock metadata_uuid
btrfs: remove v0 extent handling
btrfs: output extra debug info if we failed to find an inline backref
btrfs: move the !zoned assert into run_delalloc_cow
btrfs: consolidate the error handling in run_delalloc_nocow
...
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Pull iomap updates from Darrick Wong:
"We've got some big changes for this release -- I'm very happy to be
landing willy's work to enable large folios for the page cache for
general read and write IOs when the fs can make contiguous space
allocations, and Ritesh's work to track sub-folio dirty state to
eliminate the write amplification problems inherent in using large
folios.
As a bonus, io_uring can now process write completions in the caller's
context instead of bouncing through a workqueue, which should reduce
io latency dramatically. IOWs, XFS should see a nice performance bump
for both IO paths.
Summary:
- Make large writes to the page cache fill sparse parts of the cache
with large folios, then use large memcpy calls for the large folio.
- Track the per-block dirty state of each large folio so that a
buffered write to a single byte on a large folio does not result in
a (potentially) multi-megabyte writeback IO.
- Allow some directio completions to be performed in the initiating
task's context instead of punting through a workqueue. This will
reduce latency for some io_uring requests"
* tag 'iomap-6.6-merge-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (26 commits)
iomap: support IOCB_DIO_CALLER_COMP
io_uring/rw: add write support for IOCB_DIO_CALLER_COMP
fs: add IOCB flags related to passing back dio completions
iomap: add IOMAP_DIO_INLINE_COMP
iomap: only set iocb->private for polled bio
iomap: treat a write through cache the same as FUA
iomap: use an unsigned type for IOMAP_DIO_* defines
iomap: cleanup up iomap_dio_bio_end_io()
iomap: Add per-block dirty state tracking to improve performance
iomap: Allocate ifs in ->write_begin() early
iomap: Refactor iomap_write_delalloc_punch() function out
iomap: Use iomap_punch_t typedef
iomap: Fix possible overflow condition in iomap_write_delalloc_scan
iomap: Add some uptodate state handling helpers for ifs state bitmap
iomap: Drop ifs argument from iomap_set_range_uptodate()
iomap: Rename iomap_page to iomap_folio_state and others
iomap: Copy larger chunks from userspace
iomap: Create large folios in the buffered write path
filemap: Allow __filemap_get_folio to allocate large folios
filemap: Add fgf_t typedef
...
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs timestamp updates from Christian Brauner:
"This adds VFS support for multi-grain timestamps and converts tmpfs,
xfs, ext4, and btrfs to use them. This carries acks from all relevant
filesystems.
The VFS always uses coarse-grained timestamps when updating the ctime
and mtime after a change. This has the benefit of allowing filesystems
to optimize away a lot of metadata updates, down to around 1 per
jiffy, even when a file is under heavy writes.
Unfortunately, this has always been an issue when we're exporting via
NFSv3, which relies on timestamps to validate caches. A lot of changes
can happen in a jiffy, so timestamps aren't sufficient to help the
client decide to invalidate the cache.
Even with NFSv4, a lot of exported filesystems don't properly support
a change attribute and are subject to the same problems with timestamp
granularity. Other applications have similar issues with timestamps
(e.g., backup applications).
If we were to always use fine-grained timestamps, that would improve
the situation, but that becomes rather expensive, as the underlying
filesystem would have to log a lot more metadata updates.
This introduces fine-grained timestamps that are used when they are
actively queried.
This uses the 31st bit of the ctime tv_nsec field to indicate that
something has queried the inode for the mtime or ctime. When this flag
is set, on the next mtime or ctime update, the kernel will fetch a
fine-grained timestamp instead of the usual coarse-grained one.
As POSIX generally mandates that when the mtime changes, the ctime
must also change the kernel always stores normalized ctime values, so
only the first 30 bits of the tv_nsec field are ever used.
Filesytems can opt into this behavior by setting the FS_MGTIME flag in
the fstype. Filesystems that don't set this flag will continue to use
coarse-grained timestamps.
Various preparatory changes, fixes and cleanups are included:
- Fixup all relevant places where POSIX requires updating ctime
together with mtime. This is a wide-range of places and all
maintainers provided necessary Acks.
- Add new accessors for inode->i_ctime directly and change all
callers to rely on them. Plain accesses to inode->i_ctime are now
gone and it is accordingly rename to inode->__i_ctime and commented
as requiring accessors.
- Extend generic_fillattr() to pass in a request mask mirroring in a
sense the statx() uapi. This allows callers to pass in a request
mask to only get a subset of attributes filled in.
- Rework timestamp updates so it's possible to drop the @now
parameter the update_time() inode operation and associated helpers.
- Add inode_update_timestamps() and convert all filesystems to it
removing a bunch of open-coding"
* tag 'v6.6-vfs.ctime' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (107 commits)
btrfs: convert to multigrain timestamps
ext4: switch to multigrain timestamps
xfs: switch to multigrain timestamps
tmpfs: add support for multigrain timestamps
fs: add infrastructure for multigrain timestamps
fs: drop the timespec64 argument from update_time
xfs: have xfs_vn_update_time gets its own timestamp
fat: make fat_update_time get its own timestamp
fat: remove i_version handling from fat_update_time
ubifs: have ubifs_update_time use inode_update_timestamps
btrfs: have it use inode_update_timestamps
fs: drop the timespec64 arg from generic_update_time
fs: pass the request_mask to generic_fillattr
fs: remove silly warning from current_time
gfs2: fix timestamp handling on quota inodes
fs: rename i_ctime field to __i_ctime
selinux: convert to ctime accessor functions
security: convert to ctime accessor functions
apparmor: convert to ctime accessor functions
sunrpc: convert to ctime accessor functions
...
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Patch series "New page table range API", v6.
This patchset changes the API used by the MM to set up page table entries.
The four APIs are:
set_ptes(mm, addr, ptep, pte, nr)
update_mmu_cache_range(vma, addr, ptep, nr)
flush_dcache_folio(folio)
flush_icache_pages(vma, page, nr)
flush_dcache_folio() isn't technically new, but no architecture
implemented it, so I've done that for them. The old APIs remain around
but are mostly implemented by calling the new interfaces.
The new APIs are based around setting up N page table entries at once.
The N entries belong to the same PMD, the same folio and the same VMA, so
ptep++ is a legitimate operation, and locking is taken care of for you.
Some architectures can do a better job of it than just a loop, but I have
hesitated to make too deep a change to architectures I don't understand
well.
One thing I have changed in every architecture is that PG_arch_1 is now a
per-folio bit instead of a per-page bit when used for dcache clean/dirty
tracking. This was something that would have to happen eventually, and it
makes sense to do it now rather than iterate over every page involved in a
cache flush and figure out if it needs to happen.
The point of all this is better performance, and Fengwei Yin has measured
improvement on x86. I suspect you'll see improvement on your architecture
too. Try the new will-it-scale test mentioned here:
https://lore.kernel.org/linux-mm/20230206140639.538867-5-fengwei.yin@intel.com/
You'll need to run it on an XFS filesystem and have
CONFIG_TRANSPARENT_HUGEPAGE set.
This patchset is the basis for much of the anonymous large folio work
being done by Ryan, so it's received quite a lot of testing over the last
few months.
This patch (of 38):
Determine if a value lies within a range more efficiently (subtraction +
comparison vs two comparisons and an AND). It also has useful (under some
circumstances) behaviour if the range exceeds the maximum value of the
type. Convert all the conflicting definitions of in_range() within the
kernel; some can use the generic definition while others need their own
definition.
Link: https://lkml.kernel.org/r/20230802151406.3735276-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230802151406.3735276-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When doing a relocation, there is a chance that at the time of
btrfs_reloc_clone_csums(), there is no checksum for the corresponding
region.
In this case, btrfs_finish_ordered_zoned()'s sum points to an invalid item
and so ordered_extent's logical is set to some invalid value. Then,
btrfs_lookup_block_group() in btrfs_zone_finish_endio() failed to find a
block group and will hit an assert or a null pointer dereference as
following.
This can be reprodcued by running btrfs/028 several times (e.g, 4 to 16
times) with a null_blk setup. The device's zone size and capacity is set to
32 MB and the storage size is set to 5 GB on my setup.
KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f]
CPU: 6 PID: 3105720 Comm: kworker/u16:13 Tainted: G W 6.5.0-rc6-kts+ #1
Hardware name: Supermicro Super Server/X10SRL-F, BIOS 2.0 12/17/2015
Workqueue: btrfs-endio-write btrfs_work_helper [btrfs]
RIP: 0010:btrfs_zone_finish_endio.part.0+0x34/0x160 [btrfs]
Code: 41 54 49 89 fc 55 48 89 f5 53 e8 57 7d fc ff 48 8d b8 88 00 00 00 48 89 c3 48 b8 00 00 00 00 00
> 3c 02 00 0f 85 02 01 00 00 f6 83 88 00 00 00 01 0f 84 a8 00 00
RSP: 0018:ffff88833cf87b08 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000011 RSI: 0000000000000004 RDI: 0000000000000088
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed102877b827
R10: ffff888143bdc13b R11: ffff888125b1cbc0 R12: ffff888143bdc000
R13: 0000000000007000 R14: ffff888125b1cba8 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88881e500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3ed85223d5 CR3: 00000001519b4005 CR4: 00000000001706e0
Call Trace:
<TASK>
? die_addr+0x3c/0xa0
? exc_general_protection+0x148/0x220
? asm_exc_general_protection+0x22/0x30
? btrfs_zone_finish_endio.part.0+0x34/0x160 [btrfs]
? btrfs_zone_finish_endio.part.0+0x19/0x160 [btrfs]
btrfs_finish_one_ordered+0x7b8/0x1de0 [btrfs]
? rcu_is_watching+0x11/0xb0
? lock_release+0x47a/0x620
? btrfs_finish_ordered_zoned+0x59b/0x800 [btrfs]
? __pfx_btrfs_finish_one_ordered+0x10/0x10 [btrfs]
? btrfs_finish_ordered_zoned+0x358/0x800 [btrfs]
? __smp_call_single_queue+0x124/0x350
? rcu_is_watching+0x11/0xb0
btrfs_work_helper+0x19f/0xc60 [btrfs]
? __pfx_try_to_wake_up+0x10/0x10
? _raw_spin_unlock_irq+0x24/0x50
? rcu_is_watching+0x11/0xb0
process_one_work+0x8c1/0x1430
? __pfx_lock_acquire+0x10/0x10
? __pfx_process_one_work+0x10/0x10
? __pfx_do_raw_spin_lock+0x10/0x10
? _raw_spin_lock_irq+0x52/0x60
worker_thread+0x100/0x12c0
? __kthread_parkme+0xc1/0x1f0
? __pfx_worker_thread+0x10/0x10
kthread+0x2ea/0x3c0
? __pfx_kthread+0x10/0x10
ret_from_fork+0x30/0x70
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1b/0x30
</TASK>
On the zoned mode, writing to pre-allocated region means data relocation
write. Such write always uses WRITE command so there is no need of splitting
and rewriting logical address. Thus, we can just skip the function for the
case.
Fixes: cbfce4c7fbde ("btrfs: optimize the logical to physical mapping for zoned writes")
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This reproduces the bug fixed by "btrfs: fix incorrect splitting in
btrfs_drop_extent_map_range", we were improperly calculating the range
for the split extent. Add a test that exercises this scenario and
validates that we get the correct resulting extent_maps in our tree.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This helper is different from the normal add_extent_mapping in that it
will stuff an em into a gap that exists between overlapping em's in the
tree. It appeared there was a bug so I wrote a self test to validate it
did the correct thing when it worked with two side by side ems.
Thankfully it is correct, but more testing is better.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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While investigating weird problems with the extent_map I wrote a self
test testing the various edge cases of btrfs_drop_extent_map_range.
This can split in different ways and behaves different in each case, so
test the various edge cases to make sure everything is functioning
properly.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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scrub_stripe_read_repair_worker()
Currently the scrub_stripe_read_repair_worker() only does reads to
rebuild the corrupted sectors, it doesn't do any writeback.
The design is mostly to put writeback into a more ordered manner, to
co-operate with dev-replace with zoned mode, which requires every write
to be submitted in their bytenr order.
However the writeback for repaired sectors into the original mirror
doesn't need such strong sync requirement, as it can only happen for
non-zoned devices.
This patch would move the writeback for repaired sectors into
scrub_stripe_read_repair_worker(), which removes two calls sites for
repaired sectors writeback. (one from flush_scrub_stripes(), one from
scrub_raid56_parity_stripe())
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The workqueue fs_info->scrub_worker would go ordered workqueue if it's a
device replace operation.
However the scrub is relying on multiple workers to do data csum
verification, and we always submit several read requests in a row.
Thus there is no need to use ordered workqueue just for dev-replace.
We have extra synchronization (the main thread will always
submit-and-wait for dev-replace writes) to handle it for zoned devices.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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[REGRESSION]
There are several regression reports about the scrub performance with
v6.4 kernel.
On a PCIe 3.0 device, the old v6.3 kernel can go 3GB/s scrub speed, but
v6.4 can only go 1GB/s, an obvious 66% performance drop.
[CAUSE]
Iostat shows a very different behavior between v6.3 and v6.4 kernel:
Device r/s rkB/s rrqm/s %rrqm r_await rareq-sz aqu-sz %util
nvme0n1p3 9731.00 3425544.00 17237.00 63.92 2.18 352.02 21.18 100.00
nvme0n1p3 15578.00 993616.00 5.00 0.03 0.09 63.78 1.32 100.00
The upper one is v6.3 while the lower one is v6.4.
There are several obvious differences:
- Very few read merges
This turns out to be a behavior change that we no longer do bio
plug/unplug.
- Very low aqu-sz
This is due to the submit-and-wait behavior of flush_scrub_stripes(),
and extra extent/csum tree search.
Both behaviors are not that obvious on SATA SSDs, as SATA SSDs have NCQ
to merge the reads, while SATA SSDs can not handle high queue depth well
either.
[FIX]
For now this patch focuses on the read speed fix. Dev-replace replace
speed needs more work.
For the read part, we go two directions to fix the problems:
- Re-introduce blk plug/unplug to merge read requests
This is pretty simple, and the behavior is pretty easy to observe.
This would enlarge the average read request size to 512K.
- Introduce multi-group reads and no longer wait for each group
Instead of the old behavior, which submits 8 stripes and waits for
them, here we would enlarge the total number of stripes to 16 * 8.
Which is 8M per device, the same limit as the old scrub in-flight
bios size limit.
Now every time we fill a group (8 stripes), we submit them and
continue to next stripes.
Only when the full 16 * 8 stripes are all filled, we submit the
remaining ones (the last group), and wait for all groups to finish.
Then submit the repair writes and dev-replace writes.
This should enlarge the queue depth.
This would greatly improve the merge rate (thus read block size) and
queue depth:
Before (with regression, and cached extent/csum path):
Device r/s rkB/s rrqm/s %rrqm r_await rareq-sz aqu-sz %util
nvme0n1p3 20666.00 1318240.00 10.00 0.05 0.08 63.79 1.63 100.00
After (with all patches applied):
nvme0n1p3 5165.00 2278304.00 30557.00 85.54 0.55 441.10 2.81 100.00
i.e. 1287 to 2224 MB/s.
CC: stable@vger.kernel.org # 6.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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One of the bottleneck of the new scrub code is the extra csum tree
search.
The old code would only do the csum tree search for each scrub bio,
which can be as large as 512KiB, thus they can afford to allocate a new
path each time.
But the new scrub code is doing csum tree search for each stripe, which
is only 64KiB, this means we'd better re-use the same csum path during
each search.
This patch would introduce a per-sctx path for csum tree search, as we
don't need to re-allocate the path every time we need to do a csum tree
search.
With this change we can further improve the queue depth and improve the
scrub read performance:
Before (with regression and cached extent tree path):
Device r/s rkB/s rrqm/s %rrqm r_await rareq-sz aqu-sz %util
nvme0n1p3 15875.00 1013328.00 12.00 0.08 0.08 63.83 1.35 100.00
After (with both cached extent/csum tree path):
nvme0n1p3 17759.00 1133280.00 10.00 0.06 0.08 63.81 1.50 100.00
Fixes: e02ee89baa66 ("btrfs: scrub: switch scrub_simple_mirror() to scrub_stripe infrastructure")
CC: stable@vger.kernel.org # 6.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
