Add support for defragging files via btrfsctl -d. Avoid OOM on extent tree
defrag.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

Btrfs: fsx delalloc fixes

Signed-off-by: Chris Mason <chris.mason@oracle.com>

Btrfs: Add file data csums back in via hooks in the extent map code

Signed-off-by: Chris Mason <chris.mason@oracle.com>

Btrfs: Add delayed allocation to the extent based page tree code

Signed-off-by: Chris Mason <chris.mason@oracle.com>

Btrfs: Extent based page cache code. This uses an rbtree of extents and tests
instead of buffer heads.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

Btrfs: fix race between using extent maps and merging them

We have a few cases where we allow an extent map that is in an extent map
tree to be merged with other extents in the tree. Suc

Btrfs: fix race between using extent maps and merging them

We have a few cases where we allow an extent map that is in an extent map
tree to be merged with other extents in the tree. Such cases include the
unpinning of an extent after the respective ordered extent completed or
after logging an extent during a fast fsync. This can lead to subtle and
dangerous problems because when doing the merge some other task might be
using the same extent map and as consequence see an inconsistent state of
the extent map - for example sees the new length but has seen the old start
offset.

With luck this triggers a BUG_ON(), and not some silent bug, such as the
following one in __do_readpage():

$ cat -n fs/btrfs/extent_io.c
3061 static int __do_readpage(struct extent_io_tree *tree,
3062 struct page *page,
(...)
3127 em = __get_extent_map(inode, page, pg_offset, cur,
3128 end - cur + 1, get_extent, em_cached);
3129 if (IS_ERR_OR_NULL(em)) {
3130 SetPageError(page);
3131 unlock_extent(tree, cur, end);
3132 break;
3133 }
3134 extent_offset = cur - em->start;
3135 BUG_ON(extent_map_end(em) <= cur);
(...)

Consider the following example scenario, where we end up hitting the
BUG_ON() in __do_readpage().

We have an inode with a size of 8KiB and 2 extent maps:

extent A: file offset 0, length 4KiB, disk_bytenr = X, persisted on disk by
a previous transaction

extent B: file offset 4KiB, length 4KiB, disk_bytenr = X + 4KiB, not yet
persisted but writeback started for it already. The extent map
is pinned since there's writeback and an ordered extent in
progress, so it can not be merged with extent map A yet

The following sequence of steps leads to the BUG_ON():

1) The ordered extent for extent B completes, the respective page gets its
writeback bit cleared and the extent map is unpinned, at that point it
is not yet merged with extent map A because it's in the list of modified
extents;

2) Due to memory pressure, or some other reason, the MM subsystem releases
the page corresponding to extent B - btrfs_releasepage() is called and
returns 1, meaning the page can be released as it's not dirty, not under
writeback anymore and the extent range is not locked in the inode's
iotree. However the extent map is not released, either because we are
not in a context that allows memory allocations to block or because the
inode's size is smaller than 16MiB - in this case our inode has a size
of 8KiB;

3) Task B needs to read extent B and ends up __do_readpage() through the
btrfs_readpage() callback. At __do_readpage() it gets a reference to
extent map B;

4) Task A, doing a fast fsync, calls clear_em_loggin() against extent map B
while holding the write lock on the inode's extent map tree - this
results in try_merge_map() being called and since it's possible to merge
extent map B with extent map A now (the extent map B was removed from
the list of modified extents), the merging begins - it sets extent map
B's start offset to 0 (was 4KiB), but before it increments the map's
length to 8KiB (4kb + 4KiB), task A is at:

BUG_ON(extent_map_end(em) <= cur);

The call to extent_map_end() sees the extent map has a start of 0
and a length still at 4KiB, so it returns 4KiB and 'cur' is 4KiB, so
the BUG_ON() is triggered.

So it's dangerous to modify an extent map that is in the tree, because some
other task might have got a reference to it before and still using it, and
needs to see a consistent map while using it. Generally this is very rare
since most paths that lookup and use extent maps also have the file range
locked in the inode's iotree. The fsync path is pretty much the only
exception where we don't do it to avoid serialization with concurrent
reads.

Fix this by not allowing an extent map do be merged if if it's being used
by tasks other then the one attempting to merge the extent map (when the
reference count of the extent map is greater than 2).

Reported-by: ryusuke1925 <st13s20@gm.ibaraki-ct.ac.jp>
Reported-by: Koki Mitani <koki.mitani.xg@hco.ntt.co.jp>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=206211
CC: stable@vger.kernel.org # 4.4+
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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btrfs: remove extent_map::bdev

We can now remove the bdev from extent_map. Previous patches made sure
that bio_set_dev is correctly in all places and that we don't need to
grab it fr

btrfs: remove extent_map::bdev

We can now remove the bdev from extent_map. Previous patches made sure
that bio_set_dev is correctly in all places and that we don't need to
grab it from latest_bdev or pass it around inside the extent map.

Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: assert extent_map bdevs and lookup_map and split

This is a preparatory patch for removing extent_map::bdev. There's some
history behind the code so this is only precaution to catc

btrfs: assert extent_map bdevs and lookup_map and split

This is a preparatory patch for removing extent_map::bdev. There's some
history behind the code so this is only precaution to catch if things
break before the actual removal happens.

Logically, comparing a raw low-level block device (bdev) does not make
sense for extent maps (high-level objects). This had no effect in
practice but was quite confusing in the code. The lookup_map is set iff
EXTENT_FLAG_FS_MAPPING is set.

The two pointers were stored in the same bytes and used potentially in
two meanings. Now they're split, so the asserts are in place to check
that the condition will not change.

The lookup map pointer misused bdev, this has been changed in commit
95617d69326c ("btrfs: cleanup, stop casting for extent_map->lookup
everywhere") to the explicit type. But the semantics hasn't changed and
bdev was not actually used to decide if maps are mergeable.

Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: assert extent map tree lock in add_extent_mapping

As add_extent_mapping is called from several functions, let's add the
lock annotation. The tree is going to be modified so it mus

btrfs: assert extent map tree lock in add_extent_mapping

As add_extent_mapping is called from several functions, let's add the
lock annotation. The tree is going to be modified so it must be the
exclusive lock.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: Optimize unallocated chunks discard

Currently unallocated chunks are always trimmed. For example
2 consecutive trims on large storage would trim freespace twice
irrespective o

btrfs: Optimize unallocated chunks discard

Currently unallocated chunks are always trimmed. For example
2 consecutive trims on large storage would trim freespace twice
irrespective of whether the space was actually allocated or not between
those trims.

Optimise this behavior by exploiting the newly introduced alloc_state
tree of btrfs_device. A new CHUNK_TRIMMED bit is used to mark
those unallocated chunks which have been trimmed and have not been
allocated afterwards. On chunk allocation the respective underlying devices'
physical space will have its CHUNK_TRIMMED flag cleared. This avoids
submitting discards for space which hasn't been changed since the last
time discard was issued.

This applies to the single mount period of the filesystem as the
information is not stored permanently.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: replace pending/pinned chunks lists with io tree

The pending chunks list contains chunks that are allocated in the
current transaction but haven't been created yet. The pinned chu

btrfs: replace pending/pinned chunks lists with io tree

The pending chunks list contains chunks that are allocated in the
current transaction but haven't been created yet. The pinned chunks
list contains chunks that are being released in the current transaction.
Both describe chunks that are not reflected on disk as in use but are
unavailable just the same.

The pending chunks list is anchored by the transaction handle, which
means that we need to hold a reference to a transaction when working
with the list.

The way we use them is by iterating over both lists to perform
comparisons on the stripes they describe for each device. This is
backwards and requires that we keep a transaction handle open while
we're trimming.

This patchset adds an extent_io_tree to btrfs_device that maintains
the allocation state of the device. Extents are set dirty when
chunks are first allocated -- when the extent maps are added to the
mapping tree. They're cleared when last removed -- when the extent
maps are removed from the mapping tree. This matches the lifespan
of the pending and pinned chunks list and allows us to do trims
on unallocated space safely without pinning the transaction for what
may be a lengthy operation. We can also use this io tree to mark
which chunks have already been trimmed so we don't repeat the operation.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: Remove impossible condition from mergable_maps

We can never have extents marked as EXTENT_MAP_DELALLOC since this
value is only ever used by btrfs_get_extent_fiemap. In this case

btrfs: Remove impossible condition from mergable_maps

We can never have extents marked as EXTENT_MAP_DELALLOC since this
value is only ever used by btrfs_get_extent_fiemap. In this case the
extent map is created by btrfs_get_extent_fiemap and is never really
published, this flag is used to return the corresponding userspace one.
Considering this, it's pointless having a check for EXTENT_MAP_DELALLOC
in mergable_maps. Just remove it.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: Fix typos in comments and strings

The typos accumulate over time so once in a while time they get fixed in
a large patch.

Signed-off-by: Andrea Gelmini <andrea.gelmini@ge

btrfs: Fix typos in comments and strings

The typos accumulate over time so once in a while time they get fixed in
a large patch.

Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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Btrfs: extent_map: use rb_first_cached

rb_first_cached() trades an extra pointer "leftmost" for doing the
same job as rb_first() but in O(1).

As evict_inode_truncate_pages() rem

Btrfs: extent_map: use rb_first_cached

rb_first_cached() trades an extra pointer "leftmost" for doing the
same job as rb_first() but in O(1).

As evict_inode_truncate_pages() removes all extent mapping by always
looking for the first rb entry, it's helpful to use rb_first_cached
instead.

For more details about the optimization see patch "Btrfs: delayed-refs:
use rb_first_cached for href_root".

Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: change remove_extent_mapping to return void

remove_extent_mapping uses the variable "ret" for return value, but it
is not modified after initialzation. Further, I find that any of

btrfs: change remove_extent_mapping to return void

remove_extent_mapping uses the variable "ret" for return value, but it
is not modified after initialzation. Further, I find that any of the
callers do not handle the return value and the callees are only simple
functions so the return values does not need to be passed.

Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: use fs_info for btrfs_handle_em_exist tracepoint

We really want to know to which filesystem the extent map events belong,
but as it cannot be reached from the extent_map pointers,

btrfs: use fs_info for btrfs_handle_em_exist tracepoint

We really want to know to which filesystem the extent map events belong,
but as it cannot be reached from the extent_map pointers, we need to
pass it down the callchain.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: replace GPL boilerplate by SPDX -- sources

Remove GPL boilerplate text (long, short, one-line) and keep the rest,
ie. personal, company or original source copyright statements. Ad

btrfs: replace GPL boilerplate by SPDX -- sources

Remove GPL boilerplate text (long, short, one-line) and keep the rest,
ie. personal, company or original source copyright statements. Add the
SPDX header.

Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: add more __cold annotations

The __cold functions are placed to a special section, as they're
expected to be called rarely. This could help i-cache prefetches or help
compiler

btrfs: add more __cold annotations

The __cold functions are placed to a special section, as they're
expected to be called rarely. This could help i-cache prefetches or help
compiler to decide which branches are more/less likely to be taken
without any other annotations needed.

Though we can't add more __exit annotations, it's still possible to add
__cold (that's also added with __exit). That way the following function
categories are tagged:

- printf wrappers, error messages
- exit helpers

Signed-off-by: David Sterba <dsterba@suse.com>

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Btrfs: add tracepoint for em's EEXIST case

This is adding a tracepoint 'btrfs_handle_em_exist' to help debug the
subtle bugs around merge_extent_mapping.

Signed-off-by: Liu Bo <

Btrfs: add tracepoint for em's EEXIST case

This is adding a tracepoint 'btrfs_handle_em_exist' to help debug the
subtle bugs around merge_extent_mapping.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: remove unused hardirq.h

Preempt counter APIs have been split out, currently, hardirq.h just
includes irq_enter/exit APIs which are not used by btrfs at all.

So, remove th

btrfs: remove unused hardirq.h

Preempt counter APIs have been split out, currently, hardirq.h just
includes irq_enter/exit APIs which are not used by btrfs at all.

So, remove the unused hardirq.h.

Signed-off-by: Yang Shi <yang.s@alibaba-inc.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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Btrfs: noinline merge_extent_mapping

In order to debug subtle bugs around merge_extent_mapping(), perf probe
can be used to check the arguments, but sometimes merge_extent_mapping()

Btrfs: noinline merge_extent_mapping

In order to debug subtle bugs around merge_extent_mapping(), perf probe
can be used to check the arguments, but sometimes merge_extent_mapping()
got inlined by compiler and couldn't be probed.

This is adding noinline attribute to merge_extent_mapping().

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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Btrfs: add WARN_ONCE to detect unexpected error from merge_extent_mapping

This is a subtle case, so in order to understand the problem, it'd be good
to know the content of existing and e

Btrfs: add WARN_ONCE to detect unexpected error from merge_extent_mapping

This is a subtle case, so in order to understand the problem, it'd be good
to know the content of existing and em when any error occurs.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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Btrfs: move extent map specific code to extent_map.c

These helpers are extent map specific, move them to extent_map.c.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by:

Btrfs: move extent map specific code to extent_map.c

These helpers are extent map specific, move them to extent_map.c.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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btrfs: convert extent_map.refs from atomic_t to refcount_t

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter.

btrfs: convert extent_map.refs from atomic_t to refcount_t

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...