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The dentries and inodes are created when referenced in the lookup code.
There's no reason to call fsnotify_*() functions when they are created by
a reference. It doesn't make any sense.
Link: https://lore.kernel.org/linux-trace-kernel/20240201002719.GS2087318@ZenIV/
Link: https://lore.kernel.org/linux-trace-kernel/20240201161617.166973329@goodmis.org
Cc: stable@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Fixes: a376007917776 ("eventfs: Implement functions to create files and dirs when accessed");
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Some of the eventfs_inode structure has holes in it. Rework the structure
to be a bit more condensed, and also remove the no longer used llist
field.
Link: https://lore.kernel.org/linux-trace-kernel/20240201161617.002321438@goodmis.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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There should never be a case where an evenfs_inode is being freed without
is_freed being set. Add a WARN_ON_ONCE() if it ever happens. That would
mean there was one too many put_ei()s.
Link: https://lore.kernel.org/linux-trace-kernel/20240201161616.843551963@goodmis.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The eventfs inode had pointers to dentries (and child dentries) without
actually holding a refcount on said pointer. That is fundamentally
broken, and while eventfs tried to then maintain coherence with dentries
going away by hooking into the '.d_iput' callback, that doesn't actually
work since it's not ordered wrt lookups.
There were two reasonms why eventfs tried to keep a pointer to a dentry:
- the creation of a 'events' directory would actually have a stable
dentry pointer that it created with tracefs_start_creating().
And it needed that dentry when tearing it all down again in
eventfs_remove_events_dir().
This use is actually ok, because the special top-level events
directory dentries are actually stable, not just a temporary cache of
the eventfs data structures.
- the 'eventfs_inode' (aka ei) needs to stay around as long as there
are dentries that refer to it.
It then used these dentry pointers as a replacement for doing
reference counting: it would try to make sure that there was only
ever one dentry associated with an event_inode, and keep a child
dentry array around to see which dentries might still refer to the
parent ei.
This gets rid of the invalid dentry pointer use, and renames the one
valid case to a different name to make it clear that it's not just any
random dentry.
The magic child dentry array that is kind of a "reverse reference list"
is simply replaced by having child dentries take a ref to the ei. As
does the directory dentries. That makes the broken use case go away.
Link: https://lore.kernel.org/linux-trace-kernel/202401291043.e62e89dc-oliver.sang@intel.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240131185513.280463000@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: c1504e510238 ("eventfs: Implement eventfs dir creation functions")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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In order for the dentries to stay up-to-date with the eventfs changes,
just add a 'd_revalidate' function that checks the 'is_freed' bit.
Also, clean up the dentry release to actually use d_release() rather
than the slightly odd d_iput() function. We don't care about the inode,
all we want to do is to get rid of the refcount to the eventfs data
added by dentry->d_fsdata.
It would probably be cleaner to make eventfs its own filesystem, or at
least set its own dentry ops when looking up eventfs files. But as it
is, only eventfs dentries use d_fsdata, so we don't really need to split
these things up by use.
Another thing that might be worth doing is to make all eventfs lookups
mark their dentries as not worth caching. We could do that with
d_delete(), but the DCACHE_DONTCACHE flag would likely be even better.
As it is, the dentries are all freeable, but they only tend to get freed
at memory pressure rather than more proactively. But that's a separate
issue.
Link: https://lore.kernel.org/linux-trace-kernel/202401291043.e62e89dc-oliver.sang@intel.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240131185513.124644253@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: c1504e510238 ("eventfs: Implement eventfs dir creation functions")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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It's never used
Link: https://lore.kernel.org/linux-trace-kernel/202401291043.e62e89dc-oliver.sang@intel.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240131185512.961772428@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: c1504e510238 ("eventfs: Implement eventfs dir creation functions")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The dentry lookup for eventfs files was very broken, and had lots of
signs of the old situation where the filesystem names were all created
statically in the dentry tree, rather than being looked up dynamically
based on the eventfs data structures.
You could see it in the naming - how it claimed to "create" dentries
rather than just look up the dentries that were given it.
You could see it in various nonsensical and very incorrect operations,
like using "simple_lookup()" on the dentries that were passed in, which
only results in those dentries becoming negative dentries. Which meant
that any other lookup would possibly return ENOENT if it saw that
negative dentry before the data was then later filled in.
You could see it in the immense amount of nonsensical code that didn't
actually just do lookups.
Link: https://lore.kernel.org/linux-trace-kernel/202401291043.e62e89dc-oliver.sang@intel.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240131233227.73db55e1@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes: c1504e510238 ("eventfs: Implement eventfs dir creation functions")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The eventfs_find_events() code tries to walk up the tree to find the
event directory that a dentry belongs to, in order to then find the
eventfs inode that is associated with that event directory.
However, it uses an odd combination of walking the dentry parent,
looking up the eventfs inode associated with that, and then looking up
the dentry from there. Repeat.
But the code shouldn't have back-pointers to dentries in the first
place, and it should just walk the dentry parenthood chain directly.
Similarly, 'set_top_events_ownership()' looks up the dentry from the
eventfs inode, but the only reason it wants a dentry is to look up the
superblock in order to look up the root dentry.
But it already has the real filesystem inode, which has that same
superblock pointer. So just pass in the superblock pointer using the
information that's already there, instead of looking up extraneous data
that is irrelevant.
Link: https://lore.kernel.org/linux-trace-kernel/202401291043.e62e89dc-oliver.sang@intel.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240131185512.638645365@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: c1504e510238 ("eventfs: Implement eventfs dir creation functions")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The tracefs-specific fields in the inode were not initialized before the
inode was exposed to others through the dentry with 'd_instantiate()'.
Move the field initializations up to before the d_instantiate.
Link: https://lore.kernel.org/linux-trace-kernel/20240131185512.478449628@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202401291043.e62e89dc-oliver.sang@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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eventfs uses the tracefs_inode and assumes that it's already initialized
to zero. That is, it doesn't set fields to zero (like ti->private) after
getting its tracefs_inode. This causes bugs due to stale values.
Just initialize the entire structure to zero on allocation so there isn't
any more surprises.
This is a partial fix to access to ti->private. The assignment still needs
to be made before the dentry is instantiated.
Link: https://lore.kernel.org/linux-trace-kernel/20240131185512.315825944@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202401291043.e62e89dc-oliver.sang@intel.com
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The 'eventfs_update_gid()' function is no longer called, so remove it
(and the helper function it uses).
Link: https://lore.kernel.org/all/CAHk-=wj+DsZZ=2iTUkJ-Nojs9fjYMvPs1NuoM3yK7aTDtJfPYQ@mail.gmail.com/
Fixes: 8186fff7ab64 ("tracefs/eventfs: Use root and instance inodes as default ownership")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The eventfs inodes and directories are allocated when referenced. But this
leaves the issue of keeping consistent inode numbers and the number is
only saved in the inode structure itself. When the inode is no longer
referenced, it can be freed. When the file that the inode was representing
is referenced again, the inode is once again created, but the inode number
needs to be the same as it was before.
Just making the inode numbers the same for all files is fine, but that
does not work with directories. The find command will check for loops via
the inode number and having the same inode number for directories triggers:
# find /sys/kernel/tracing
find: File system loop detected;
'/sys/kernel/debug/tracing/events/initcall/initcall_finish' is part of the same file system loop as
'/sys/kernel/debug/tracing/events/initcall'.
[..]
Linus pointed out that the eventfs_inode structure ends with a single
32bit int, and on 64 bit machines, there's likely a 4 byte hole due to
alignment. We can use this hole to store the inode number for the
eventfs_inode. All directories in eventfs are represented by an
eventfs_inode and that data structure can hold its inode number.
That last int was also purposely placed at the end of the structure to
prevent holes from within. Now that there's a 4 byte number to hold the
inode, both the inode number and the last integer can be moved up in the
structure for better cache locality, where the llist and rcu fields can be
moved to the end as they are only used when the eventfs_inode is being
deleted.
Link: https://lore.kernel.org/all/CAMuHMdXKiorg-jiuKoZpfZyDJ3Ynrfb8=X+c7x0Eewxn-YRdCA@mail.gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240122152748.46897388@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Fixes: 53c41052ba31 ("eventfs: Have the inodes all for files and directories all be the same")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
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Pull more bcachefs updates from Kent Overstreet:
"Some fixes, Some refactoring, some minor features:
- Assorted prep work for disk space accounting rewrite
- BTREE_TRIGGER_ATOMIC: after combining our trigger callbacks, this
makes our trigger context more explicit
- A few fixes to avoid excessive transaction restarts on
multithreaded workloads: fstests (in addition to ktest tests) are
now checking slowpath counters, and that's shaking out a few bugs
- Assorted tracepoint improvements
- Starting to break up bcachefs_format.h and move on disk types so
they're with the code they belong to; this will make room to start
documenting the on disk format better.
- A few minor fixes"
* tag 'bcachefs-2024-01-21' of https://evilpiepirate.org/git/bcachefs: (46 commits)
bcachefs: Improve inode_to_text()
bcachefs: logged_ops_format.h
bcachefs: reflink_format.h
bcachefs; extents_format.h
bcachefs: ec_format.h
bcachefs: subvolume_format.h
bcachefs: snapshot_format.h
bcachefs: alloc_background_format.h
bcachefs: xattr_format.h
bcachefs: dirent_format.h
bcachefs: inode_format.h
bcachefs; quota_format.h
bcachefs: sb-counters_format.h
bcachefs: counters.c -> sb-counters.c
bcachefs: comment bch_subvolume
bcachefs: bch_snapshot::btime
bcachefs: add missing __GFP_NOWARN
bcachefs: opts->compression can now also be applied in the background
bcachefs: Prep work for variable size btree node buffers
bcachefs: grab s_umount only if snapshotting
...
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Add line breaks - inode_to_text() is now much easier to read.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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bcachefs_format.h has gotten too big; let's do some organizing.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Add a field to bch_snapshot for creation time; this will be important
when we start exposing the snapshot tree to userspace.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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The "apply this compression method in the background" paths now use the
compression option if background_compression is not set; this means that
setting or changing the compression option will cause existing data to
be compressed accordingly in the background.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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bcachefs btree nodes are big - typically 256k - and btree roots are
pinned in memory. As we're now up to 18 btrees, we now have significant
memory overhead in mostly empty btree roots.
And in the future we're going to start enforcing that certain btree node
boundaries exist, to solve lock contention issues - analagous to XFS's
AGIs.
Thus, we need to start allocating smaller btree node buffers when we
can. This patch changes code that refers to the filesystem constant
c->opts.btree_node_size to refer to the btree node buffer size -
btree_buf_bytes() - where appropriate.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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When I was testing mongodb over bcachefs with compression,
there is a lockdep warning when snapshotting mongodb data volume.
$ cat test.sh
prog=bcachefs
$prog subvolume create /mnt/data
$prog subvolume create /mnt/data/snapshots
while true;do
$prog subvolume snapshot /mnt/data /mnt/data/snapshots/$(date +%s)
sleep 1s
done
$ cat /etc/mongodb.conf
systemLog:
destination: file
logAppend: true
path: /mnt/data/mongod.log
storage:
dbPath: /mnt/data/
lockdep reports:
[ 3437.452330] ======================================================
[ 3437.452750] WARNING: possible circular locking dependency detected
[ 3437.453168] 6.7.0-rc7-custom+ #85 Tainted: G E
[ 3437.453562] ------------------------------------------------------
[ 3437.453981] bcachefs/35533 is trying to acquire lock:
[ 3437.454325] ffffa0a02b2b1418 (sb_writers#10){.+.+}-{0:0}, at: filename_create+0x62/0x190
[ 3437.454875]
but task is already holding lock:
[ 3437.455268] ffffa0a02b2b10e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: bch2_fs_file_ioctl+0x232/0xc90 [bcachefs]
[ 3437.456009]
which lock already depends on the new lock.
[ 3437.456553]
the existing dependency chain (in reverse order) is:
[ 3437.457054]
-> #3 (&type->s_umount_key#48){.+.+}-{3:3}:
[ 3437.457507] down_read+0x3e/0x170
[ 3437.457772] bch2_fs_file_ioctl+0x232/0xc90 [bcachefs]
[ 3437.458206] __x64_sys_ioctl+0x93/0xd0
[ 3437.458498] do_syscall_64+0x42/0xf0
[ 3437.458779] entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.459155]
-> #2 (&c->snapshot_create_lock){++++}-{3:3}:
[ 3437.459615] down_read+0x3e/0x170
[ 3437.459878] bch2_truncate+0x82/0x110 [bcachefs]
[ 3437.460276] bchfs_truncate+0x254/0x3c0 [bcachefs]
[ 3437.460686] notify_change+0x1f1/0x4a0
[ 3437.461283] do_truncate+0x7f/0xd0
[ 3437.461555] path_openat+0xa57/0xce0
[ 3437.461836] do_filp_open+0xb4/0x160
[ 3437.462116] do_sys_openat2+0x91/0xc0
[ 3437.462402] __x64_sys_openat+0x53/0xa0
[ 3437.462701] do_syscall_64+0x42/0xf0
[ 3437.462982] entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.463359]
-> #1 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}:
[ 3437.463843] down_write+0x3b/0xc0
[ 3437.464223] bch2_write_iter+0x5b/0xcc0 [bcachefs]
[ 3437.464493] vfs_write+0x21b/0x4c0
[ 3437.464653] ksys_write+0x69/0xf0
[ 3437.464839] do_syscall_64+0x42/0xf0
[ 3437.465009] entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.465231]
-> #0 (sb_writers#10){.+.+}-{0:0}:
[ 3437.465471] __lock_acquire+0x1455/0x21b0
[ 3437.465656] lock_acquire+0xc6/0x2b0
[ 3437.465822] mnt_want_write+0x46/0x1a0
[ 3437.465996] filename_create+0x62/0x190
[ 3437.466175] user_path_create+0x2d/0x50
[ 3437.466352] bch2_fs_file_ioctl+0x2ec/0xc90 [bcachefs]
[ 3437.466617] __x64_sys_ioctl+0x93/0xd0
[ 3437.466791] do_syscall_64+0x42/0xf0
[ 3437.466957] entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.467180]
other info that might help us debug this:
[ 3437.469670] 2 locks held by bcachefs/35533:
other info that might help us debug this:
[ 3437.467507] Chain exists of:
sb_writers#10 --> &c->snapshot_create_lock --> &type->s_umount_key#48
[ 3437.467979] Possible unsafe locking scenario:
[ 3437.468223] CPU0 CPU1
[ 3437.468405] ---- ----
[ 3437.468585] rlock(&type->s_umount_key#48);
[ 3437.468758] lock(&c->snapshot_create_lock);
[ 3437.469030] lock(&type->s_umount_key#48);
[ 3437.469291] rlock(sb_writers#10);
[ 3437.469434]
*** DEADLOCK ***
[ 3437.469670] 2 locks held by bcachefs/35533:
[ 3437.469838] #0: ffffa0a02ce00a88 (&c->snapshot_create_lock){++++}-{3:3}, at: bch2_fs_file_ioctl+0x1e3/0xc90 [bcachefs]
[ 3437.470294] #1: ffffa0a02b2b10e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: bch2_fs_file_ioctl+0x232/0xc90 [bcachefs]
[ 3437.470744]
stack backtrace:
[ 3437.470922] CPU: 7 PID: 35533 Comm: bcachefs Kdump: loaded Tainted: G E 6.7.0-rc7-custom+ #85
[ 3437.471313] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
[ 3437.471694] Call Trace:
[ 3437.471795] <TASK>
[ 3437.471884] dump_stack_lvl+0x57/0x90
[ 3437.472035] check_noncircular+0x132/0x150
[ 3437.472202] __lock_acquire+0x1455/0x21b0
[ 3437.472369] lock_acquire+0xc6/0x2b0
[ 3437.472518] ? filename_create+0x62/0x190
[ 3437.472683] ? lock_is_held_type+0x97/0x110
[ 3437.472856] mnt_want_write+0x46/0x1a0
[ 3437.473025] ? filename_create+0x62/0x190
[ 3437.473204] filename_create+0x62/0x190
[ 3437.473380] user_path_create+0x2d/0x50
[ 3437.473555] bch2_fs_file_ioctl+0x2ec/0xc90 [bcachefs]
[ 3437.473819] ? lock_acquire+0xc6/0x2b0
[ 3437.474002] ? __fget_files+0x2a/0x190
[ 3437.474195] ? __fget_files+0xbc/0x190
[ 3437.474380] ? lock_release+0xc5/0x270
[ 3437.474567] ? __x64_sys_ioctl+0x93/0xd0
[ 3437.474764] ? __pfx_bch2_fs_file_ioctl+0x10/0x10 [bcachefs]
[ 3437.475090] __x64_sys_ioctl+0x93/0xd0
[ 3437.475277] do_syscall_64+0x42/0xf0
[ 3437.475454] entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.475691] RIP: 0033:0x7f2743c313af
======================================================
In __bch2_ioctl_subvolume_create(), we grab s_umount unconditionally
and unlock it at the end of the function. There is a comment
"why do we need this lock?" about the lock coming from
commit 42d237320e98 ("bcachefs: Snapshot creation, deletion")
The reason is that __bch2_ioctl_subvolume_create() calls
sync_inodes_sb() which enforce locked s_umount to writeback all dirty
nodes before doing snapshot works.
Fix it by read locking s_umount for snapshotting only and unlocking
s_umount after sync_inodes_sb().
Signed-off-by: Su Yue <glass.su@suse.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
bch_fs::snapshots is allocated by kvzalloc in __snapshot_t_mut.
It should be freed by kvfree not kfree.
Or umount will triger:
[ 406.829178 ] BUG: unable to handle page fault for address: ffffe7b487148008
[ 406.830676 ] #PF: supervisor read access in kernel mode
[ 406.831643 ] #PF: error_code(0x0000) - not-present page
[ 406.832487 ] PGD 0 P4D 0
[ 406.832898 ] Oops: 0000 [#1] PREEMPT SMP PTI
[ 406.833512 ] CPU: 2 PID: 1754 Comm: umount Kdump: loaded Tainted: G OE 6.7.0-rc7-custom+ #90
[ 406.834746 ] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
[ 406.835796 ] RIP: 0010:kfree+0x62/0x140
[ 406.836197 ] Code: 80 48 01 d8 0f 82 e9 00 00 00 48 c7 c2 00 00 00 80 48 2b 15 78 9f 1f 01 48 01 d0 48 c1 e8 0c 48 c1 e0 06 48 03 05 56 9f 1f 01 <48> 8b 50 08 48 89 c7 f6 c2 01 0f 85 b0 00 00 00 66 90 48 8b 07 f6
[ 406.837810 ] RSP: 0018:ffffb9d641607e48 EFLAGS: 00010286
[ 406.838213 ] RAX: ffffe7b487148000 RBX: ffffb9d645200000 RCX: ffffb9d641607dc4
[ 406.838738 ] RDX: 000065bb00000000 RSI: ffffffffc0d88b84 RDI: ffffb9d645200000
[ 406.839217 ] RBP: ffff9a4625d00068 R08: 0000000000000001 R09: 0000000000000001
[ 406.839650 ] R10: 0000000000000001 R11: 000000000000001f R12: ffff9a4625d4da80
[ 406.840055 ] R13: ffff9a4625d00000 R14: ffffffffc0e2eb20 R15: 0000000000000000
[ 406.840451 ] FS: 00007f0a264ffb80(0000) GS:ffff9a4e2d500000(0000) knlGS:0000000000000000
[ 406.840851 ] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 406.841125 ] CR2: ffffe7b487148008 CR3: 000000018c4d2000 CR4: 00000000000006f0
[ 406.841464 ] Call Trace:
[ 406.841583 ] <TASK>
[ 406.841682 ] ? __die+0x1f/0x70
[ 406.841828 ] ? page_fault_oops+0x159/0x470
[ 406.842014 ] ? fixup_exception+0x22/0x310
[ 406.842198 ] ? exc_page_fault+0x1ed/0x200
[ 406.842382 ] ? asm_exc_page_fault+0x22/0x30
[ 406.842574 ] ? bch2_fs_release+0x54/0x280 [bcachefs]
[ 406.842842 ] ? kfree+0x62/0x140
[ 406.842988 ] ? kfree+0x104/0x140
[ 406.843138 ] bch2_fs_release+0x54/0x280 [bcachefs]
[ 406.843390 ] kobject_put+0xb7/0x170
[ 406.843552 ] deactivate_locked_super+0x2f/0xa0
[ 406.843756 ] cleanup_mnt+0xba/0x150
[ 406.843917 ] task_work_run+0x59/0xa0
[ 406.844083 ] exit_to_user_mode_prepare+0x197/0x1a0
[ 406.844302 ] syscall_exit_to_user_mode+0x16/0x40
[ 406.844510 ] do_syscall_64+0x4e/0xf0
[ 406.844675 ] entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 406.844907 ] RIP: 0033:0x7f0a2664e4fb
Signed-off-by: Su Yue <glass.su@suse.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
Fixes: 023f9ac9f70f bcachefs: Delete dio read alignment check
Reported-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
The variable tmp is being assigned a value but it isn't being
read afterwards. The assignment is redundant and so tmp can be
removed.
Cleans up clang scan build warning:
warning: Although the value stored to 'ret' is used in the enclosing
expression, the value is never actually read from 'ret'
[deadcode.DeadStores]
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
drop_locks_do() should not be used in a fastpath without first trying
the do in nonblocking mode - the unlock and relock will cause excessive
transaction restarts and potentially livelocking with other threads that
are contending for the same locks.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
Factor out bch2_journal_bufs_to_text(), and use it in the
journal_entry_full() tracepoint; when we can't get a journal reservation
we need to know the outstanding journal entry sizes to know if the
problem is due to excessive flushing.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
When issuing discards, we may need to flush the journal if there's too
many buckets that can't be discarded until a journal flush.
But the heuristic was bad; we should be comparing the number of buckets
that need to flushes against the number of free buckets, not the number
of buckets we saw.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
Also print out the data_opts, so that we can see what specifically is
being done to an extent.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
This fixes a bug with rebalance IOs getting stuck with reads completed,
but writes never being issued.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
It appears this was accidentally deleted at some point - also, do a bit
of cleanup.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
Drop t he loop in bch2_kthread_io_clock_wait(): this allows the code
that uses it to be woken up for other reasons, and fixes a bug where
rebalance wouldn't wake up when a scan was requested.
This raises the possibility of spurious wakeups, but callers should
always be able to handle that reasonably well.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
Some (buggy!) compilers have issues with this.
Fixes: https://github.com/koverstreet/bcachefs/issues/625
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
We don't have to take locks in any particular ordering - we'll make
forward progress just fine - but if we try to stick to an ordering, it
can help to avoid excessive would_deadlock transaction restarts.
This tweaks the reflink path to take extents btree locks in the right
order.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
