[ Upstream commit 5229a658f6 ]
Len Brown has reported that system suspend sometimes fail due to
inability to freeze a task working in ext4_trim_fs() for one minute.
Trimming a large filesystem on a disk that slowly processes discard
requests can indeed take a long time. Since discard is just an advisory
call, it is perfectly fine to interrupt it at any time and the return
number of discarded blocks until that moment. Do that when we detect the
task is being frozen.
Cc: stable@kernel.org
Reported-by: Len Brown <lenb@kernel.org>
Suggested-by: Dave Chinner <david@fromorbit.com>
References: https://bugzilla.kernel.org/show_bug.cgi?id=216322
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230913150504.9054-2-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 45e4ab320c ]
Currently we set the group's trimmed bit in ext4_trim_all_free() based
on return value of ext4_try_to_trim_range(). However when we will want
to abort trimming because of suspend attempt, we want to return success
from ext4_try_to_trim_range() but not set the trimmed bit. Instead
implementing awkward propagation of this information, just move setting
of trimmed bit into ext4_try_to_trim_range() when the whole group is
trimmed.
Cc: stable@kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230913150504.9054-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 7fda67e8c3 upstream.
With the configuration PAGE_SIZE 64k and filesystem blocksize 64k,
a problem occurred when more than 13 million files were directly created
under a directory:
EXT4-fs error (device xx): ext4_dx_csum_set:492: inode #xxxx: comm xxxxx: dir seems corrupt? Run e2fsck -D.
EXT4-fs error (device xx): ext4_dx_csum_verify:463: inode #xxxx: comm xxxxx: dir seems corrupt? Run e2fsck -D.
EXT4-fs error (device xx): dx_probe:856: inode #xxxx: block 8188: comm xxxxx: Directory index failed checksum
When enough files are created, the fake_dirent->reclen will be 0xffff.
it doesn't equal to the blocksize 65536, i.e. 0x10000.
But it is not the same condition when blocksize equals to 4k.
when enough files are created, the fake_dirent->reclen will be 0x1000.
it equals to the blocksize 4k, i.e. 0x1000.
The problem seems to be related to the limitation of the 16-bit field
when the blocksize is set to 64k.
To address this, helpers like ext4_rec_len_{from,to}_disk has already
been introduced to complete the conversion between the encoded and the
plain form of rec_len.
So fix this one by using the helper, and all the other in this file too.
Cc: stable@kernel.org
Fixes: dbe8944404 ("ext4: Calculate and verify checksums for htree nodes")
Suggested-by: Andreas Dilger <adilger@dilger.ca>
Suggested-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Shida Zhang <zhangshida@kylinos.cn>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20230803060938.1929759-1-zhangshida@kylinos.cn
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit bc056e7163 ]
When we calculate the end position of ext4_free_extent, this position may
be exactly where ext4_lblk_t (i.e. uint) overflows. For example, if
ac_g_ex.fe_logical is 4294965248 and ac_orig_goal_len is 2048, then the
computed end is 0x100000000, which is 0. If ac->ac_o_ex.fe_logical is not
the first case of adjusting the best extent, that is, new_bex_end > 0, the
following BUG_ON will be triggered:
=========================================================
kernel BUG at fs/ext4/mballoc.c:5116!
invalid opcode: 0000 [#1] PREEMPT SMP PTI
CPU: 3 PID: 673 Comm: xfs_io Tainted: G E 6.5.0-rc1+ #279
RIP: 0010:ext4_mb_new_inode_pa+0xc5/0x430
Call Trace:
<TASK>
ext4_mb_use_best_found+0x203/0x2f0
ext4_mb_try_best_found+0x163/0x240
ext4_mb_regular_allocator+0x158/0x1550
ext4_mb_new_blocks+0x86a/0xe10
ext4_ext_map_blocks+0xb0c/0x13a0
ext4_map_blocks+0x2cd/0x8f0
ext4_iomap_begin+0x27b/0x400
iomap_iter+0x222/0x3d0
__iomap_dio_rw+0x243/0xcb0
iomap_dio_rw+0x16/0x80
=========================================================
A simple reproducer demonstrating the problem:
mkfs.ext4 -F /dev/sda -b 4096 100M
mount /dev/sda /tmp/test
fallocate -l1M /tmp/test/tmp
fallocate -l10M /tmp/test/file
fallocate -i -o 1M -l16777203M /tmp/test/file
fsstress -d /tmp/test -l 0 -n 100000 -p 8 &
sleep 10 && killall -9 fsstress
rm -f /tmp/test/tmp
xfs_io -c "open -ad /tmp/test/file" -c "pwrite -S 0xff 0 8192"
We simply refactor the logic for adjusting the best extent by adding
a temporary ext4_free_extent ex and use extent_logical_end() to avoid
overflow, which also simplifies the code.
Cc: stable@kernel.org # 6.4
Fixes: 93cdf49f6e ("ext4: Fix best extent lstart adjustment logic in ext4_mb_new_inode_pa()")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20230724121059.11834-3-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit bedc5d3463 ]
Let's say we want to allocate 2 blocks starting from 4294966386, after
predicting the file size, start is aligned to 4294965248, len is changed
to 2048, then end = start + size = 0x100000000. Since end is of
type ext4_lblk_t, i.e. uint, end is truncated to 0.
This causes (pa->pa_lstart >= end) to always hold when checking if the
current extent to be allocated crosses already preallocated blocks, so the
resulting ac_g_ex may cross already preallocated blocks. Hence we convert
the end type to loff_t and use pa_logical_end() to avoid overflow.
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20230724121059.11834-4-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 43bbddc067 ]
When we use lstart + len to calculate the end of free extent or prealloc
space, it may exceed the maximum value of 4294967295(0xffffffff) supported
by ext4_lblk_t and cause overflow, which may lead to various problems.
Therefore, we add two helper functions, extent_logical_end() and
pa_logical_end(), to limit the type of end to loff_t, and also convert
lstart to loff_t for calculation to avoid overflow.
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20230724121059.11834-2-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 194505b55d upstream.
The commit referenced below opened up concurrent unaligned dio under
shared locking for pure overwrites. In doing so, it enabled use of
the IOMAP_DIO_OVERWRITE_ONLY flag and added a warning on unexpected
-EAGAIN returns as an extra precaution, since ext4 does not retry
writes in such cases. The flag itself is advisory in this case since
ext4 checks for unaligned I/Os and uses appropriate locking up
front, rather than on a retry in response to -EAGAIN.
As it turns out, the warning check is susceptible to false positives
because there are scenarios where -EAGAIN can be expected from lower
layers without necessarily having IOCB_NOWAIT set on the iocb. For
example, one instance of the warning has been seen where io_uring
sets IOCB_HIPRI, which in turn results in REQ_POLLED|REQ_NOWAIT on
the bio. This results in -EAGAIN if the block layer is unable to
allocate a request, etc. [Note that there is an outstanding patch to
untangle REQ_POLLED and REQ_NOWAIT such that the latter relies on
IOCB_NOWAIT, which would also address this instance of the warning.]
Another instance of the warning has been reproduced by syzbot. A dio
write is interrupted down in __get_user_pages_locked() waiting on
the mm lock and returns -EAGAIN up the stack. If the iomap dio
iteration layer has made no progress on the write to this point,
-EAGAIN returns up to the filesystem and triggers the warning.
This use of the overwrite flag in ext4 is precautionary and
half-baked. I.e., ext4 doesn't actually implement overwrite checking
in the iomap callbacks when the flag is set, so the only extra
verification it provides are i_size checks in the generic iomap dio
layer. Combined with the tendency for false positives, the added
verification is not worth the extra trouble. Remove the flag,
associated warning, and update the comments to document when
concurrent unaligned dio writes are allowed and why said flag is not
used.
Cc: stable@kernel.org
Reported-by: syzbot+5050ad0fb47527b1808a@syzkaller.appspotmail.com
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Fixes: 310ee0902b ("ext4: allow concurrent unaligned dio overwrites")
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230810165559.946222-1-bfoster@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7ca4b085f4 upstream.
If the filename casefolding fails, we'll be leaking memory from the
fscrypt_name struct, namely from the 'crypto_buf.name' member.
Make sure we free it in the error path on both ext4_fname_setup_filename()
and ext4_fname_prepare_lookup() functions.
Cc: stable@kernel.org
Fixes: 1ae98e295f ("ext4: optimize match for casefolded encrypted dirs")
Signed-off-by: Luís Henriques <lhenriques@suse.de>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20230803091713.13239-1-lhenriques@suse.de
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 68228da51c upstream.
When setup_system_zone, flex_bg is not initialized so it is always 1.
Use a new helper function, ext4_num_base_meta_blocks() which does not
depend on sbi->s_log_groups_per_flex being initialized.
[ Squashed two patches in the Link URL's below together into a single
commit, which is simpler to review/understand. Also fix checkpatch
warnings. --TYT ]
Cc: stable@kernel.org
Signed-off-by: Wang Jianjian <wangjianjian0@foxmail.com>
Link: https://lore.kernel.org/r/tencent_21AF0D446A9916ED5C51492CC6C9A0A77B05@qq.com
Link: https://lore.kernel.org/r/tencent_D744D1450CC169AEA77FCF0A64719909ED05@qq.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 768d612f79 upstream.
Yikebaer reported an issue:
==================================================================
BUG: KASAN: slab-use-after-free in ext4_es_insert_extent+0xc68/0xcb0
fs/ext4/extents_status.c:894
Read of size 4 at addr ffff888112ecc1a4 by task syz-executor/8438
CPU: 1 PID: 8438 Comm: syz-executor Not tainted 6.5.0-rc5 #1
Call Trace:
[...]
kasan_report+0xba/0xf0 mm/kasan/report.c:588
ext4_es_insert_extent+0xc68/0xcb0 fs/ext4/extents_status.c:894
ext4_map_blocks+0x92a/0x16f0 fs/ext4/inode.c:680
ext4_alloc_file_blocks.isra.0+0x2df/0xb70 fs/ext4/extents.c:4462
ext4_zero_range fs/ext4/extents.c:4622 [inline]
ext4_fallocate+0x251c/0x3ce0 fs/ext4/extents.c:4721
[...]
Allocated by task 8438:
[...]
kmem_cache_zalloc include/linux/slab.h:693 [inline]
__es_alloc_extent fs/ext4/extents_status.c:469 [inline]
ext4_es_insert_extent+0x672/0xcb0 fs/ext4/extents_status.c:873
ext4_map_blocks+0x92a/0x16f0 fs/ext4/inode.c:680
ext4_alloc_file_blocks.isra.0+0x2df/0xb70 fs/ext4/extents.c:4462
ext4_zero_range fs/ext4/extents.c:4622 [inline]
ext4_fallocate+0x251c/0x3ce0 fs/ext4/extents.c:4721
[...]
Freed by task 8438:
[...]
kmem_cache_free+0xec/0x490 mm/slub.c:3823
ext4_es_try_to_merge_right fs/ext4/extents_status.c:593 [inline]
__es_insert_extent+0x9f4/0x1440 fs/ext4/extents_status.c:802
ext4_es_insert_extent+0x2ca/0xcb0 fs/ext4/extents_status.c:882
ext4_map_blocks+0x92a/0x16f0 fs/ext4/inode.c:680
ext4_alloc_file_blocks.isra.0+0x2df/0xb70 fs/ext4/extents.c:4462
ext4_zero_range fs/ext4/extents.c:4622 [inline]
ext4_fallocate+0x251c/0x3ce0 fs/ext4/extents.c:4721
[...]
==================================================================
The flow of issue triggering is as follows:
1. remove es
raw es es removed es1
|-------------------| -> |----|.......|------|
2. insert es
es insert es1 merge with es es1 merge with es and free es1
|----|.......|------| -> |------------|------| -> |-------------------|
es merges with newes, then merges with es1, frees es1, then determines
if es1->es_len is 0 and triggers a UAF.
The code flow is as follows:
ext4_es_insert_extent
es1 = __es_alloc_extent(true);
es2 = __es_alloc_extent(true);
__es_remove_extent(inode, lblk, end, NULL, es1)
__es_insert_extent(inode, &newes, es1) ---> insert es1 to es tree
__es_insert_extent(inode, &newes, es2)
ext4_es_try_to_merge_right
ext4_es_free_extent(inode, es1) ---> es1 is freed
if (es1 && !es1->es_len)
// Trigger UAF by determining if es1 is used.
We determine whether es1 or es2 is used immediately after calling
__es_remove_extent() or __es_insert_extent() to avoid triggering a
UAF if es1 or es2 is freed.
Reported-by: Yikebaer Aizezi <yikebaer61@gmail.com>
Closes: https://lore.kernel.org/lkml/CALcu4raD4h9coiyEBL4Bm0zjDwxC2CyPiTwsP3zFuhot6y9Beg@mail.gmail.com
Fixes: 2a69c45008 ("ext4: using nofail preallocation in ext4_es_insert_extent()")
Cc: stable@kernel.org
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230815070808.3377171-1-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 1524773425 ]
Running generic/475(filesystem consistent tests after power cut) could
easily trigger unattached inode error while doing fsck:
Unattached zero-length inode 39405. Clear? no
Unattached inode 39405
Connect to /lost+found? no
Above inconsistence is caused by following process:
P1 P2
ext4_create
inode = ext4_new_inode_start_handle // itable records nlink=1
ext4_add_nondir
err = ext4_add_entry // ENOSPC
ext4_append
ext4_bread
ext4_getblk
ext4_map_blocks // returns ENOSPC
drop_nlink(inode) // won't be updated into disk inode
ext4_orphan_add(handle, inode)
ext4_orphan_file_add
ext4_journal_stop(handle)
jbd2_journal_commit_transaction // commit success
>> power cut <<
ext4_fill_super
ext4_load_and_init_journal // itable records nlink=1
ext4_orphan_cleanup
ext4_process_orphan
if (inode->i_nlink) // true, inode won't be deleted
Then, allocated inode will be reserved on disk and corresponds to no
dentries, so e2fsck reports 'unattached inode' problem.
The problem won't happen if orphan file feature is disabled, because
ext4_orphan_add() will update disk inode in orphan list mode. There
are several places not updating disk inode while putting inode into
orphan area, such as ext4_add_nondir(), ext4_symlink() and whiteout
in ext4_rename(). Fix it by updating inode into disk in all error
branches of these places.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217605
Fixes: 02f310fcf4 ("ext4: Speedup ext4 orphan inode handling")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230628132011.650383-1-chengzhihao1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 60c672b7f2 ]
ngroups is ext4_group_t (unsigned int) while next_linear_group treat it
in int. If ngroups is bigger than max number described by int, it will
be treat as a negative number. Then "return group + 1 >= ngroups ? 0 :
group + 1;" may keep returning 0.
Switch int to ext4_group_t in next_linear_group to fix the overflow.
Fixes: 196e402adf ("ext4: improve cr 0 / cr 1 group scanning")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20230801143204.2284343-3-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a9ce5993a0 ]
Group corruption check will access memory of grp and will trigger kernel
crash if grp is NULL. So do NULL check before corruption check.
Fixes: 5354b2af34 ("ext4: allow ext4_get_group_info() to fail")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20230801143204.2284343-2-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
During allocations, while looking for preallocations(PA) in the per
inode rbtree, we can't do a direct traversal of the tree because
ext4_mb_discard_group_preallocation() can paralelly mark the pa deleted
and that can cause direct traversal to skip some entries. This was
leading to a BUG_ON() being hit [1] when we missed a PA that could satisfy
our request and ultimately tried to create a new PA that would overlap
with the missed one.
To makes sure we handle that case while still keeping the performance of
the rbtree, we make use of the fact that the only pa that could possibly
overlap the original goal start is the one that satisfies the below
conditions:
1. It must have it's logical start immediately to the left of
(ie less than) original logical start.
2. It must not be deleted
To find this pa we use the following traversal method:
1. Descend into the rbtree normally to find the immediate neighboring
PA. Here we keep descending irrespective of if the PA is deleted or if
it overlaps with our request etc. The goal is to find an immediately
adjacent PA.
2. If the found PA is on right of original goal, use rb_prev() to find
the left adjacent PA.
3. Check if this PA is deleted and keep moving left with rb_prev() until
a non deleted PA is found.
4. This is the PA we are looking for. Now we can check if it can satisfy
the original request and proceed accordingly.
This approach also takes care of having deleted PAs in the tree.
(While we are at it, also fix a possible overflow bug in calculating the
end of a PA)
[1] https://lore.kernel.org/linux-ext4/CA+G9fYv2FRpLqBZf34ZinR8bU2_ZRAUOjKAD3+tKRFaEQHtt8Q@mail.gmail.com/
Cc: stable@kernel.org # 6.4
Fixes: 3872778664 ("ext4: Use rbtrees to manage PAs instead of inode i_prealloc_list")
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reviewed-by: Ritesh Harjani (IBM) ritesh.list@gmail.com
Tested-by: Ritesh Harjani (IBM) ritesh.list@gmail.com
Link: https://lore.kernel.org/r/edd2efda6a83e6343c5ace9deea44813e71dbe20.1690045963.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
In ext4_mb_choose_next_group_best_avail(), we want the start order to be
1 less than goal length and the min_order to be, at max, 1 more than the
original length. This commit fixes an off by one issue that arose due to
the fact that 1 << fls(n) > (n).
After all the processing:
order = 1 order below goal len
min_order = maximum of the three:-
- order - trim_order
- 1 order below B2C(s_stripe)
- 1 order above original len
Cc: stable@kernel.org
Fixes: 33122aa930 ("ext4: Add allocation criteria 1.5 (CR1_5)")
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://lore.kernel.org/r/20230609103403.112807-1-ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When run on a file system where the inline_data feature has been
enabled, xfstests generic/269, generic/270, and generic/476 cause ext4
to emit error messages indicating that inline directory entries are
corrupted. This occurs because the inline offset used to locate
inline directory entries in the inode body is not updated when an
xattr in that shared region is deleted and the region is shifted in
memory to recover the space it occupied. If the deleted xattr precedes
the system.data attribute, which points to the inline directory entries,
that attribute will be moved further up in the region. The inline
offset continues to point to whatever is located in system.data's former
location, with unfortunate effects when used to access directory entries
or (presumably) inline data in the inode body.
Cc: stable@kernel.org
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Link: https://lore.kernel.org/r/20230522181520.1570360-1-enwlinux@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Merge tag 'fs_for_v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull misc filesystem updates from Jan Kara:
- Rewrite kmap_local() handling in ext2
- Convert ext2 direct IO path to iomap (with some infrastructure tweaks
associated with that)
- Convert two boilerplate licenses in udf to SPDX identifiers
- Other small udf, ext2, and quota fixes and cleanups
* tag 'fs_for_v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
udf: Fix uninitialized array access for some pathnames
ext2: Drop fragment support
quota: fix warning in dqgrab()
quota: Properly disable quotas when add_dquot_ref() fails
fs: udf: udftime: Replace LGPL boilerplate with SPDX identifier
fs: udf: Replace GPL 2.0 boilerplate license notice with SPDX identifier
fs: Drop wait_unfrozen wait queue
ext2_find_entry()/ext2_dotdot(): callers don't need page_addr anymore
ext2_{set_link,delete_entry}(): don't bother with page_addr
ext2_put_page(): accept any pointer within the page
ext2_get_page(): saner type
ext2: use offset_in_page() instead of open-coding it as subtraction
ext2_rename(): set_link and delete_entry may fail
ext2: Add direct-io trace points
ext2: Move direct-io to use iomap
ext2: Use generic_buffers_fsync() implementation
ext4: Use generic_buffers_fsync_noflush() implementation
fs/buffer.c: Add generic_buffers_fsync*() implementation
ext2/dax: Fix ext2_setsize when len is page aligned
journalling, and block allocator subsystems. Also improve performance
for parallel DIO overwrites.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"Various cleanups and bug fixes in ext4's extent status tree,
journalling, and block allocator subsystems.
Also improve performance for parallel DIO overwrites"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (55 commits)
ext4: avoid updating the superblock on a r/o mount if not needed
jbd2: skip reading super block if it has been verified
ext4: fix to check return value of freeze_bdev() in ext4_shutdown()
ext4: refactoring to use the unified helper ext4_quotas_off()
ext4: turn quotas off if mount failed after enabling quotas
ext4: update doc about journal superblock description
ext4: add journal cycled recording support
jbd2: continue to record log between each mount
jbd2: remove j_format_version
jbd2: factor out journal initialization from journal_get_superblock()
jbd2: switch to check format version in superblock directly
jbd2: remove unused feature macros
ext4: ext4_put_super: Remove redundant checking for 'sbi->s_journal_bdev'
ext4: Fix reusing stale buffer heads from last failed mounting
ext4: allow concurrent unaligned dio overwrites
ext4: clean up mballoc criteria comments
ext4: make ext4_zeroout_es() return void
ext4: make ext4_es_insert_extent() return void
ext4: make ext4_es_insert_delayed_block() return void
ext4: make ext4_es_remove_extent() return void
...
- Yosry has also eliminated cgroup's atomic rstat flushing.
- Nhat Pham adds the new cachestat() syscall. It provides userspace
with the ability to query pagecache status - a similar concept to
mincore() but more powerful and with improved usability.
- Mel Gorman provides more optimizations for compaction, reducing the
prevalence of page rescanning.
- Lorenzo Stoakes has done some maintanance work on the get_user_pages()
interface.
- Liam Howlett continues with cleanups and maintenance work to the maple
tree code. Peng Zhang also does some work on maple tree.
- Johannes Weiner has done some cleanup work on the compaction code.
- David Hildenbrand has contributed additional selftests for
get_user_pages().
- Thomas Gleixner has contributed some maintenance and optimization work
for the vmalloc code.
- Baolin Wang has provided some compaction cleanups,
- SeongJae Park continues maintenance work on the DAMON code.
- Huang Ying has done some maintenance on the swap code's usage of
device refcounting.
- Christoph Hellwig has some cleanups for the filemap/directio code.
- Ryan Roberts provides two patch series which yield some
rationalization of the kernel's access to pte entries - use the provided
APIs rather than open-coding accesses.
- Lorenzo Stoakes has some fixes to the interaction between pagecache
and directio access to file mappings.
- John Hubbard has a series of fixes to the MM selftesting code.
- ZhangPeng continues the folio conversion campaign.
- Hugh Dickins has been working on the pagetable handling code, mainly
with a view to reducing the load on the mmap_lock.
- Catalin Marinas has reduced the arm64 kmalloc() minimum alignment from
128 to 8.
- Domenico Cerasuolo has improved the zswap reclaim mechanism by
reorganizing the LRU management.
- Matthew Wilcox provides some fixups to make gfs2 work better with the
buffer_head code.
- Vishal Moola also has done some folio conversion work.
- Matthew Wilcox has removed the remnants of the pagevec code - their
functionality is migrated over to struct folio_batch.
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Merge tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull mm updates from Andrew Morton:
- Yosry Ahmed brought back some cgroup v1 stats in OOM logs
- Yosry has also eliminated cgroup's atomic rstat flushing
- Nhat Pham adds the new cachestat() syscall. It provides userspace
with the ability to query pagecache status - a similar concept to
mincore() but more powerful and with improved usability
- Mel Gorman provides more optimizations for compaction, reducing the
prevalence of page rescanning
- Lorenzo Stoakes has done some maintanance work on the
get_user_pages() interface
- Liam Howlett continues with cleanups and maintenance work to the
maple tree code. Peng Zhang also does some work on maple tree
- Johannes Weiner has done some cleanup work on the compaction code
- David Hildenbrand has contributed additional selftests for
get_user_pages()
- Thomas Gleixner has contributed some maintenance and optimization
work for the vmalloc code
- Baolin Wang has provided some compaction cleanups,
- SeongJae Park continues maintenance work on the DAMON code
- Huang Ying has done some maintenance on the swap code's usage of
device refcounting
- Christoph Hellwig has some cleanups for the filemap/directio code
- Ryan Roberts provides two patch series which yield some
rationalization of the kernel's access to pte entries - use the
provided APIs rather than open-coding accesses
- Lorenzo Stoakes has some fixes to the interaction between pagecache
and directio access to file mappings
- John Hubbard has a series of fixes to the MM selftesting code
- ZhangPeng continues the folio conversion campaign
- Hugh Dickins has been working on the pagetable handling code, mainly
with a view to reducing the load on the mmap_lock
- Catalin Marinas has reduced the arm64 kmalloc() minimum alignment
from 128 to 8
- Domenico Cerasuolo has improved the zswap reclaim mechanism by
reorganizing the LRU management
- Matthew Wilcox provides some fixups to make gfs2 work better with the
buffer_head code
- Vishal Moola also has done some folio conversion work
- Matthew Wilcox has removed the remnants of the pagevec code - their
functionality is migrated over to struct folio_batch
* tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (380 commits)
mm/hugetlb: remove hugetlb_set_page_subpool()
mm: nommu: correct the range of mmap_sem_read_lock in task_mem()
hugetlb: revert use of page_cache_next_miss()
Revert "page cache: fix page_cache_next/prev_miss off by one"
mm/vmscan: fix root proactive reclaim unthrottling unbalanced node
mm: memcg: rename and document global_reclaim()
mm: kill [add|del]_page_to_lru_list()
mm: compaction: convert to use a folio in isolate_migratepages_block()
mm: zswap: fix double invalidate with exclusive loads
mm: remove unnecessary pagevec includes
mm: remove references to pagevec
mm: rename invalidate_mapping_pagevec to mapping_try_invalidate
mm: remove struct pagevec
net: convert sunrpc from pagevec to folio_batch
i915: convert i915_gpu_error to use a folio_batch
pagevec: rename fbatch_count()
mm: remove check_move_unevictable_pages()
drm: convert drm_gem_put_pages() to use a folio_batch
i915: convert shmem_sg_free_table() to use a folio_batch
scatterlist: add sg_set_folio()
...
This was noticed by a user who noticied that the mtime of a file
backing a loopback device was getting bumped when the loopback device
is mounted read/only. Note: This doesn't show up when doing a
loopback mount of a file directly, via "mount -o ro /tmp/foo.img
/mnt", since the loop device is set read-only when mount automatically
creates loop device. However, this is noticeable for a LUKS loop
device like this:
% cryptsetup luksOpen /tmp/foo.img test
% mount -o ro /dev/loop0 /mnt ; umount /mnt
or, if LUKS is not in use, if the user manually creates the loop
device like this:
% losetup /dev/loop0 /tmp/foo.img
% mount -o ro /dev/loop0 /mnt ; umount /mnt
The modified mtime causes rsync to do a rolling checksum scan of the
file on the local and remote side, incrementally increasing the time
to rsync the not-modified-but-touched image file.
Fixes: eee00237fa ("ext4: commit super block if fs record error when journal record without error")
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/ZIauBR7YiV3rVAHL@glitch
Reported-by: Sean Greenslade <sean@seangreenslade.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Rename ext4_quota_off_umount() to ext4_quotas_off(), and add type
parameter to replace open code in ext4_enable_quotas().
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230327141630.156875-3-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Always enable 'JBD2_CYCLE_RECORD' journal option on ext4, letting the
jbd2 continue to record new journal transactions from the recovered
journal head or the checkpointed transactions in the previous mount.
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230322013353.1843306-3-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
As discussed in [1], 'sbi->s_journal_bdev != sb->s_bdev' will always
become true if sbi->s_journal_bdev exists. Filesystem block device and
journal block device are both opened with 'FMODE_EXCL' mode, so these
two devices can't be same one. Then we can remove the redundant checking
'sbi->s_journal_bdev != sb->s_bdev' if 'sbi->s_journal_bdev' exists.
[1] https://lore.kernel.org/lkml/f86584f6-3877-ff18-47a1-2efaa12d18b2@huawei.com/
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230315013128.3911115-3-chengzhihao1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Following process makes ext4 load stale buffer heads from last failed
mounting in a new mounting operation:
mount_bdev
ext4_fill_super
| ext4_load_and_init_journal
| ext4_load_journal
| jbd2_journal_load
| load_superblock
| journal_get_superblock
| set_buffer_verified(bh) // buffer head is verified
| jbd2_journal_recover // failed caused by EIO
| goto failed_mount3a // skip 'sb->s_root' initialization
deactivate_locked_super
kill_block_super
generic_shutdown_super
if (sb->s_root)
// false, skip ext4_put_super->invalidate_bdev->
// invalidate_mapping_pages->mapping_evict_folio->
// filemap_release_folio->try_to_free_buffers, which
// cannot drop buffer head.
blkdev_put
blkdev_put_whole
if (atomic_dec_and_test(&bdev->bd_openers))
// false, systemd-udev happens to open the device. Then
// blkdev_flush_mapping->kill_bdev->truncate_inode_pages->
// truncate_inode_folio->truncate_cleanup_folio->
// folio_invalidate->block_invalidate_folio->
// filemap_release_folio->try_to_free_buffers will be skipped,
// dropping buffer head is missed again.
Second mount:
ext4_fill_super
ext4_load_and_init_journal
ext4_load_journal
ext4_get_journal
jbd2_journal_init_inode
journal_init_common
bh = getblk_unmovable
bh = __find_get_block // Found stale bh in last failed mounting
journal->j_sb_buffer = bh
jbd2_journal_load
load_superblock
journal_get_superblock
if (buffer_verified(bh))
// true, skip journal->j_format_version = 2, value is 0
jbd2_journal_recover
do_one_pass
next_log_block += count_tags(journal, bh)
// According to journal_tag_bytes(), 'tag_bytes' calculating is
// affected by jbd2_has_feature_csum3(), jbd2_has_feature_csum3()
// returns false because 'j->j_format_version >= 2' is not true,
// then we get wrong next_log_block. The do_one_pass may exit
// early whenoccuring non JBD2_MAGIC_NUMBER in 'next_log_block'.
The filesystem is corrupted here, journal is partially replayed, and
new journal sequence number actually is already used by last mounting.
The invalidate_bdev() can drop all buffer heads even racing with bare
reading block device(eg. systemd-udev), so we can fix it by invalidating
bdev in error handling path in __ext4_fill_super().
Fetch a reproducer in [Link].
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217171
Fixes: 25ed6e8a54 ("jbd2: enable journal clients to enable v2 checksumming")
Cc: stable@vger.kernel.org # v3.5
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230315013128.3911115-2-chengzhihao1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
We've had reports of significant performance regression of sub-block
(unaligned) direct writes due to the added exclusivity restrictions
in ext4. The purpose of the exclusivity requirement for unaligned
direct writes is to avoid data corruption caused by unserialized
partial block zeroing in the iomap dio layer across overlapping
writes.
XFS has similar requirements for the same underlying reasons, yet
doesn't suffer the extreme performance regression that ext4 does.
The reason for this is that XFS utilizes IOMAP_DIO_OVERWRITE_ONLY
mode, which allows for optimistic submission of concurrent unaligned
I/O and kicks back writes that require partial block zeroing such
that they can be submitted in a safe, exclusive context. Since ext4
already performs most of these checks pre-submission, it can support
something similar without necessarily relying on the iomap flag and
associated retry mechanism.
Update the dio write submission path to allow concurrent submission
of unaligned direct writes that are purely overwrite and so will not
require block zeroing. To improve readability of the various related
checks, move the unaligned I/O handling down into
ext4_dio_write_checks(), where the dio draining and force wait logic
can immediately follow the locking requirement checks. Finally, the
IOMAP_DIO_OVERWRITE_ONLY flag is set to enable a warning check as a
precaution should the ext4 overwrite logic ever become inconsistent
with the zeroing expectations of iomap dio.
The performance improvement of sub-block direct write I/O is shown
in the following fio test on a 64xcpu guest vm:
Test: fio --name=test --ioengine=libaio --direct=1 --group_reporting
--overwrite=1 --thread --size=10G --filename=/mnt/fio
--readwrite=write --ramp_time=10s --runtime=60s --numjobs=8
--blocksize=2k --iodepth=256 --allow_file_create=0
v6.2: write: IOPS=4328, BW=8724KiB/s
v6.2 (patched): write: IOPS=801k, BW=1565MiB/s
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230314130759.642710-1-bfoster@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Line wrap and slightly clarify the comments describing mballoc's
cirtiera.
Define EXT4_MB_NUM_CRS as part of the enum, so that it will
automatically get updated when criteria is added or removed.
Also fix a potential unitialized use of 'cr' variable if
CONFIG_EXT4_DEBUG is enabled.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
After ext4_es_insert_extent() returns void, the return value in
ext4_zeroout_es() is also unnecessary, so make it return void too.
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230424033846.4732-13-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Now ext4_es_insert_extent() never return error, so make it return void.
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230424033846.4732-12-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Similar to in ext4_es_insert_delayed_block(), we use preallocations that
do not fail to avoid inconsistencies, but we do not care about es that are
not must be kept, and we return 0 even if such es memory allocation fails.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230424033846.4732-9-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Similar to in ext4_es_remove_extent(), we use a no-fail preallocation
to avoid inconsistencies, except that here we may have to preallocate
two extent_status.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230424033846.4732-8-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
If __es_remove_extent() returns an error it means that when splitting
extent, allocating an extent that must be kept failed, where returning
an error directly would cause the extent tree to be inconsistent. So we
use GFP_NOFAIL to pre-allocate an extent_status and pass it to
__es_remove_extent() to avoid this problem.
In addition, since the allocated memory is outside the i_es_lock, the
extent_status tree may change and the pre-allocated extent_status is
no longer needed, so we release the pre-allocated extent_status when
es->es_len is not initialized.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230424033846.4732-7-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When splitting extent, if the second extent can not be dropped, we return
-ENOMEM and use GFP_NOFAIL to preallocate an extent_status outside of
i_es_lock and pass it to __es_remove_extent() to be used as the second
extent. This ensures that __es_remove_extent() is executed successfully,
thus ensuring consistency in the extent status tree. If the second extent
is not undroppable, we simply drop it and return 0. Then retry is no longer
necessary, remove it.
Now, __es_remove_extent() will always remove what it should, maybe more.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230424033846.4732-6-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Pass a extent_status pointer prealloc to __es_insert_extent(). If the
pointer is non-null, it is used directly when a new extent_status is
needed to avoid memory allocation failures.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230424033846.4732-5-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Factor out __es_alloc_extent() and __es_free_extent(), which only allocate
and free extent_status in these two helpers.
The ext4_es_alloc_extent() function is split into __es_alloc_extent()
and ext4_es_init_extent(). In __es_alloc_extent() we allocate memory using
GFP_KERNEL | __GFP_NOFAIL | __GFP_ZERO if the memory allocation cannot
fail, otherwise we use GFP_ATOMIC. and the ext4_es_init_extent() is used to
initialize extent_status and update related variables after a successful
allocation.
This is to prepare for the use of pre-allocated extent_status later.
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230424033846.4732-4-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
In the extent status tree, we have extents which we can just drop without
issues and extents we must not drop - this depends on the extent's status
- currently ext4_es_is_delayed() extents must stay, others may be dropped.
A helper function is added to help determine if the current extent can
be dropped, although only ext4_es_is_delayed() extents cannot be dropped
currently.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230424033846.4732-3-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
In our fault injection test, we create an ext4 file, migrate it to
non-extent based file, then punch a hole and finally trigger a WARN_ON
in the ext4_da_update_reserve_space():
EXT4-fs warning (device sda): ext4_da_update_reserve_space:369:
ino 14, used 11 with only 10 reserved data blocks
When writing back a non-extent based file, if we enable delalloc, the
number of reserved blocks will be subtracted from the number of blocks
mapped by ext4_ind_map_blocks(), and the extent status tree will be
updated. We update the extent status tree by first removing the old
extent_status and then inserting the new extent_status. If the block range
we remove happens to be in an extent, then we need to allocate another
extent_status with ext4_es_alloc_extent().
use old to remove to add new
|----------|------------|------------|
old extent_status
The problem is that the allocation of a new extent_status failed due to a
fault injection, and __es_shrink() did not get free memory, resulting in
a return of -ENOMEM. Then do_writepages() retries after receiving -ENOMEM,
we map to the same extent again, and the number of reserved blocks is again
subtracted from the number of blocks in that extent. Since the blocks in
the same extent are subtracted twice, we end up triggering WARN_ON at
ext4_da_update_reserve_space() because used > ei->i_reserved_data_blocks.
For non-extent based file, we update the number of reserved blocks after
ext4_ind_map_blocks() is executed, which causes a problem that when we call
ext4_ind_map_blocks() to create a block, it doesn't always create a block,
but we always reduce the number of reserved blocks. So we move the logic
for updating reserved blocks to ext4_ind_map_blocks() to ensure that the
number of reserved blocks is updated only after we do succeed in allocating
some new blocks.
Fixes: 5f634d064c ("ext4: Fix quota accounting error with fallocate")
Cc: stable@kernel.org
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230424033846.4732-2-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
mballoc criterias have historically been called by numbers
like CR0, CR1... however this makes it confusing to understand
what each criteria is about.
Change these criterias from numbers to symbolic names and add
relevant comments. While we are at it, also reformat and add some
comments to ext4_seq_mb_stats_show() for better readability.
Additionally, define CR_FAST which signifies the criteria
below which we can make quicker decisions like:
* quitting early if (free block < requested len)
* avoiding to scan free extents smaller than required len.
* avoiding to initialize buddy cache and work with existing cache
* limiting prefetches
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://lore.kernel.org/r/a2dc6ec5aea5e5e68cf8e788c2a964ffead9c8b0.1685449706.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
CR1_5 aims to optimize allocations which can't be satisfied in CR1. The
fact that we couldn't find a group in CR1 suggests that it would be
difficult to find a continuous extent to compleltely satisfy our
allocations. So before falling to the slower CR2, in CR1.5 we
proactively trim the the preallocations so we can find a group with
(free / fragments) big enough. This speeds up our allocation at the
cost of slightly reduced preallocation.
The patch also adds a new sysfs tunable:
* /sys/fs/ext4/<partition>/mb_cr1_5_max_trim_order
This controls how much CR1.5 can trim a request before falling to CR2.
For example, for a request of order 7 and max trim order 2, CR1.5 can
trim this upto order 5.
Suggested-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/150fdf65c8e4cc4dba71e020ce0859bcf636a5ff.1685449706.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Make the logic of searching average fragment list of a given order reusable
by abstracting it out to a differnet function. This will also avoid
code duplication in upcoming patches.
No functional changes.
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/028c11d95b17ce0285f45456709a0ca922df1b83.1685449706.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Before this patch, the call stack in ext4_run_li_request is as follows:
/*
* nr = no. of BGs we want to fetch (=s_mb_prefetch)
* prefetch_ios = no. of BGs not uptodate after
* ext4_read_block_bitmap_nowait()
*/
next_group = ext4_mb_prefetch(sb, group, nr, prefetch_ios);
ext4_mb_prefetch_fini(sb, next_group prefetch_ios);
ext4_mb_prefetch_fini() will only try to initialize buddies for BGs in
range [next_group - prefetch_ios, next_group). This is incorrect since
sometimes (prefetch_ios < nr), which causes ext4_mb_prefetch_fini() to
incorrectly ignore some of the BGs that might need initialization. This
issue is more notable now with the previous patch enabling "fetching" of
BLOCK_UNINIT BGs which are marked buffer_uptodate by default.
Fix this by passing nr to ext4_mb_prefetch_fini() instead of
prefetch_ios so that it considers the right range of groups.
Similarly, make sure we don't pass nr=0 to ext4_mb_prefetch_fini() in
ext4_mb_regular_allocator() since we might have prefetched BLOCK_UNINIT
groups that would need buddy initialization.
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/05e648ae04ec5b754207032823e9c1de9a54f87a.1685449706.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Currently, ext4_mb_prefetch() and ext4_mb_prefetch_fini() skip
BLOCK_UNINIT groups since fetching their bitmaps doesn't need disk IO.
As a consequence, we end not initializing the buddy structures and CR0/1
lists for these BGs, even though it can be done without any disk IO
overhead. Hence, don't skip such BGs during prefetch and prefetch_fini.
This improves the accuracy of CR0/1 allocation as earlier, we could have
essentially empty BLOCK_UNINIT groups being ignored by CR0/1 due to their buddy
not being initialized, leading to slower CR2 allocations. With this patch CR0/1
will be able to discover these groups as well, thus improving performance.
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/dc3130b8daf45ffe63d8a3c1edcf00eb8ba70e1f.1685449706.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When we are inside ext4_mb_complex_scan_group() in CR1, we can be sure
that this group has atleast 1 big enough continuous free extent to satisfy
our request because (free / fragments) > goal length.
Hence, instead of wasting time looping over smaller free extents, only
try to consider the free extent if we are sure that it has enough
continuous free space to satisfy goal length. This is particularly
useful when scanning highly fragmented BGs in CR1 as, without this
patch, the allocator might stop scanning early before reaching the big
enough free extent (due to ac_found > mb_max_to_scan) which causes us to
uncessarily trim the request.
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/a5473df4517c53ec940bc9b603ef83a547032a32.1685449706.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Track number of allocations where the length of blocks allocated is equal to the
length of goal blocks (post normalization). This metric could be useful if
making changes to the allocator logic in the future as it could give us
visibility into how often do we trim our requests.
PS: ac_b_ex.fe_len might get modified due to preallocation efforts and
hence we use ac_f_ex.fe_len instead since we want to compare how much the
allocator was able to actually find.
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/343620e2be8a237239ea2613a7a866ee8607e973.1685449706.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This gives better visibility into the number of extents scanned in each
particular CR. For example, this information can be used to see how out
block group scanning logic is performing when the BG is fragmented.
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/55bb6d80f6e22ed2a5a830aa045572bdffc8b1b9.1685449706.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
