Currently in ENOSPC condition when writing into unwritten space, or
punching a hole, we might need to split the extent and grow extent tree.
However since we can not allocate any new metadata blocks we'll have to
zero out unwritten part of extent or punched out part of extent, or in
the worst case return ENOSPC even though use actually does not allocate
any space.
Also in delalloc path we do reserve metadata and data blocks for the
time we're going to write out, however metadata block reservation is
very tricky especially since we expect that logical connectivity implies
physical connectivity, however that might not be the case and hence we
might end up allocating more metadata blocks than previously reserved.
So in future, metadata reservation checks should be removed since we can
not assure that we do not under reserve.
And this is where reserved space comes into the picture. When mounting
the file system we slice off a little bit of the file system space (2%
or 4096 clusters, whichever is smaller) which can be then used for the
cases mentioned above to prevent costly zeroout, or unexpected ENOSPC.
The number of reserved clusters can be set via sysfs, however it can
never be bigger than number of free clusters in the file system.
Note that this patch fixes the failure of xfstest 274 as expected.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Estimate of 27 credits for allocation of a block in extent based inode
is unnecessarily high. We can easily argue 20 is enough.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Improve mb_free_blocks speed by clearing entire range at once instead
of iterating over each bit. Freeing block-by-block also makes buddy
bitmap subtree flip twice making most of the work a no-op. Very few
bits in buddy bitmap require change, e.g. freeing entire group is a 1
bit flip only. As a result, releasing blocks of 60G file now takes
5ms instead of 2.7s. This is especially good for non-preemptive
kernels as there is no rescheduling during release.
Signed-off-by: Andrey Sidorov <qrxd43@motorola.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Values stored in s_freeclusters_counter and s_dirtyclusters_counter
are both in cluster units. Remove the cluster to block conversion
applied to s_freeclusters_counter causing an inflated estimate of
free space because s_dirtyclusters_counter is not similarly
converted. Rename free_blocks and dirty_blocks to better reflect
the units these variables contain to avoid future confusion. This
fix corrects ENOSPC failures for xfstests 127 and 231 on bigalloc
file systems.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
We didn't mark hidden quota files with S_NOQUOTA flag and thus quota was
accounted even for quota files. Thus we could recurse back to quota code
when adding new blocks to quota file which can easily deadlock. Mark
hidden quota files properly.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
existing locking ordering: journal-> i_data_sem, but
ext4_ind_migrate() grab locks in opposite order which may result in
deadlock.
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Add a new ioctl, EXT4_IOC_SWAP_BOOT which swaps i_blocks and
associated attributes (like i_blocks, i_size, i_flags, ...) from the
specified inode with inode EXT4_BOOT_LOADER_INO (#5). This is
typically used to store a boot loader in a secure part of the
filesystem, where it can't be changed by a normal user by accident.
The data blocks of the previous boot loader will be associated with
the given inode.
This usercode program is a simple example of the usage:
int main(int argc, char *argv[])
{
int fd;
int err;
if ( argc != 2 ) {
printf("usage: ext4-swap-boot-inode FILE-TO-SWAP\n");
exit(1);
}
fd = open(argv[1], O_WRONLY);
if ( fd < 0 ) {
perror("open");
exit(1);
}
err = ioctl(fd, EXT4_IOC_SWAP_BOOT);
if ( err < 0 ) {
perror("ioctl");
exit(1);
}
close(fd);
exit(0);
}
[ Modified by Theodore Ts'o to fix a number of bugs in the original code.]
Signed-off-by: Dr. Tilmann Bubeck <t.bubeck@reinform.de>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Currently when inserting extent in ext4_ext_insert_extent() we would
only try to to see if we can append new extent to the found extent. If
we can not, then we proceed with adding new extent into the extent tree,
but then possibly merging it back again.
We can avoid this situation by trying to append and prepend new extent
to the existing ones. However since the new extent can be on either
sides of the existing extent, we have to pick the right extent to try to
append/prepend to.
This patch adds the conditions to pick the right extent to
append/prepend to and adds the actual prepending condition as well. This
will also eliminate the need to use "reserved" block for possibly
growing extent tree.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Currently when converting extent to initialized we attempt to transfer
initialized block to the left neighbour if possible when certain
criteria are met. However we do not attempt to do the same for the
right neighbor.
This commit adds the possibility to transfer initialized block to the
right neighbour if:
1. We're not converting the whole extent
2. Both extents are stored in the same extent tree node
3. Right neighbor is initialized
4. Right neighbor is logically abutting the current one
5. Right neighbor is physically abutting the current one
6. Right neighbor would not overflow the length limit
This is basically the same logic as with transferring to the left. This
will gain us some performance benefits since it is faster than inserting
extent and then merging it.
It would also prevent some situation in delalloc patch when we might run
out of metadata reservation. This is due to the fact that we would
attempt to split the extent first (possibly allocating new metadata
block) even though we did not counted for that because it can (and will)
be merged again. This commit fix that scenario, because we no longer
need to split the extent in such case.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Currently on many places in ext4 we're using
ext4_get_group_no_and_offset() even though we're only interested in
knowing the block group of the particular block, not the offset within
the block group so we can use more efficient way to compute block
group.
This patch introduces ext4_get_group_number() which computes block
group for a given block much more efficiently. Use this function
instead of ext4_get_group_no_and_offset() everywhere where we're only
interested in knowing the block group.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Currently in when getting the block group number for a particular
block in ext4_block_in_group() we're using
ext4_get_group_no_and_offset() which uses do_div() to get the block
group and the remainer which is offset within the group.
We don't need all of that in ext4_block_in_group() as we only need to
figure out the group number.
This commit changes ext4_block_in_group() to calculate group number
directly. This shows as a big improvement with regards to cpu
utilization. Measuring fallocate -l 15T on fresh file system with perf
showed that 23% of cpu time was spend in the
ext4_get_group_no_and_offset(). With this change it completely
disappears from the list only bumping the occurrence of
ext4_init_block_bitmap() which is the biggest user of
ext4_block_in_group() by 4%. As the result of this change on my system
the fallocate call was approx. 10% faster.
However since there is '-g' option in mkfs which allow us setting
different groups size (mostly for developers) I've introduced new per
file system flag whether we have a standard block group size or
not. The flag is used to determine whether we can use the bit shift
optimization or not.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
It is incorrect to use list_for_each_entry_safe() for journal callback
traversial because ->next may be removed by other task:
->ext4_mb_free_metadata()
->ext4_mb_free_metadata()
->ext4_journal_callback_del()
This results in the following issue:
WARNING: at lib/list_debug.c:62 __list_del_entry+0x1c0/0x250()
Hardware name:
list_del corruption. prev->next should be ffff88019a4ec198, but was 6b6b6b6b6b6b6b6b
Modules linked in: cpufreq_ondemand acpi_cpufreq freq_table mperf coretemp kvm_intel kvm crc32c_intel ghash_clmulni_intel microcode sg xhci_hcd button sd_mod crc_t10dif aesni_intel ablk_helper cryptd lrw aes_x86_64 xts gf128mul ahci libahci pata_acpi ata_generic dm_mirror dm_region_hash dm_log dm_mod
Pid: 16400, comm: jbd2/dm-1-8 Tainted: G W 3.8.0-rc3+ #107
Call Trace:
[<ffffffff8106fb0d>] warn_slowpath_common+0xad/0xf0
[<ffffffff8106fc06>] warn_slowpath_fmt+0x46/0x50
[<ffffffff813637e9>] ? ext4_journal_commit_callback+0x99/0xc0
[<ffffffff8148cae0>] __list_del_entry+0x1c0/0x250
[<ffffffff813637bf>] ext4_journal_commit_callback+0x6f/0xc0
[<ffffffff813ca336>] jbd2_journal_commit_transaction+0x23a6/0x2570
[<ffffffff8108aa42>] ? try_to_del_timer_sync+0x82/0xa0
[<ffffffff8108b491>] ? del_timer_sync+0x91/0x1e0
[<ffffffff813d3ecf>] kjournald2+0x19f/0x6a0
[<ffffffff810ad630>] ? wake_up_bit+0x40/0x40
[<ffffffff813d3d30>] ? bit_spin_lock+0x80/0x80
[<ffffffff810ac6be>] kthread+0x10e/0x120
[<ffffffff810ac5b0>] ? __init_kthread_worker+0x70/0x70
[<ffffffff818ff6ac>] ret_from_fork+0x7c/0xb0
[<ffffffff810ac5b0>] ? __init_kthread_worker+0x70/0x70
This patch fix the issue as follows:
- ext4_journal_commit_callback() make list truly traversial safe
simply by always starting from list_head
- fix race between two ext4_journal_callback_del() and
ext4_journal_callback_try_del()
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@vger.kernel.com
In order to make it simpler to test the code which support
i_blocks/indirect-mapped inodes, support the conversion of inodes
which are less than 12 blocks and which are contained in no more than
a single extent.
The primary intended use of this code is to converting freshly created
zero-length files and empty directories.
Note that the version of chattr in e2fsprogs 1.42.7 and earlier has a
check that prevents the clearing of the extent flag. A simple patch
which allows "chattr -e <file>" to work will be checked into the
e2fsprogs git repository.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
In the case where an inode has a very stale transaction id (tid) in
i_datasync_tid or i_sync_tid, it's possible that after a very large
(2**31) number of transactions, that the tid number space might wrap,
causing tid_geq()'s calculations to fail.
Commit deeeaf13 "jbd2: fix fsync() tid wraparound bug", later modified
by commit e7b04ac0 "jbd2: don't wake kjournald unnecessarily",
attempted to fix this problem, but it only avoided kjournald spinning
forever by fixing the logic in jbd2_log_start_commit().
Unfortunately, in the codepaths in fs/ext4/fsync.c and fs/ext4/inode.c
that might call jbd2_log_start_commit() with a stale tid, those
functions will subsequently call jbd2_log_wait_commit() with the same
stale tid, and then wait for a very long time. To fix this, we
replace the calls to jbd2_log_start_commit() and
jbd2_log_wait_commit() with a call to a new function,
jbd2_complete_transaction(), which will correctly handle stale tid's.
As a bonus, jbd2_complete_transaction() will avoid locking
j_state_lock for writing unless a commit needs to be started. This
should have a small (but probably not measurable) improvement for
ext4's scalability.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Reported-by: George Barnett <gbarnett@atlassian.com>
Cc: stable@vger.kernel.org
[ Added fixup from Lukáš Czerner which only checks the assertion when
the inode is not new and is not being freed. ]
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Move common code in ext4_ind_truncate() and ext4_ext_truncate() into
ext4_truncate(). This saves over 60 lines of code.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Move common code in ext4_ind_punch_hole() and ext4_ext_punch_hole()
into ext4_punch_hole(). This saves over 150 lines of code.
This also fixes a potential bug when the punch_hole() code is racing
against indirect-to-extents or extents-to-indirect migation. We are
currently using i_mutex to protect against changes to the inode flag;
specifically, the append-only, immutable, and extents inode flags. So
we need to take i_mutex before deciding whether to use the
extents-specific or indirect-specific punch_hole code.
Also, there was a missing call to ext4_inode_block_unlocked_dio() in
the indirect punch codepath. This was added in commit 02d262dffc
to block DIO readers racing against the punch operation in the
codepath for extent-mapped inodes, but it was missing for
indirect-block mapped inodes. One of the advantages of refactoring
the code is that it makes such oversights much less likely.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The older code was far more complicated than it needed to be because
of how we spliced in the ext4's new multiblock allocator into ext3's
indirect block code. By folding ext4_alloc_blocks() into
ext4_alloc_branch(), we make the code far more understable, shave off
over 130 lines of code and half a kilobyte of compiled object code.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
After collapsing the handling of data ordered and data writeback
codepath, ext4_generic_write_end() has only one caller,
ext4_write_end(). So we fold it into ext4_write_end().
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
The only difference between how we handle data=ordered and
data=writeback is a single call to ext4_jbd2_file_inode(). Eliminate
code duplication by factoring out redundant the code paths.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
When an extent was zeroed out, we forgot to do convert from cpu to le16.
It could make us hit a BUG_ON when we try to write dirty pages out. So
fix it.
[ Also fix a bug found by Dmitry Monakhov where we were missing
le32_to_cpu() calls in the new indirect punch hole code.
There are a number of other big endian warnings found by static code
analyzers, but we'll wait for the next merge window to fix them all
up. These fixes are designed to be Obviously Correct by code
inspection, and easy to demonstrate that it won't make any
difference (and hence, won't introduce any bugs) on little endian
architectures such as x86. --tytso ]
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: CAI Qian <caiqian@redhat.com>
Reported-by: Christian Kujau <lists@nerdbynature.de>
Cc: Dmitry Monakhov <dmonakhov@openvz.org>
relatively obscure cornercases or races that were found using
regression tests.
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Merge tag 'ext4_for_linue' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 fixes from Ted Ts'o:
"Fix a number of regression and other bugs in ext4, most of which were
relatively obscure cornercases or races that were found using
regression tests."
* tag 'ext4_for_linue' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (21 commits)
ext4: fix data=journal fast mount/umount hang
ext4: fix ext4_evict_inode() racing against workqueue processing code
ext4: fix memory leakage in mext_check_coverage
ext4: use s_extent_max_zeroout_kb value as number of kb
ext4: use atomic64_t for the per-flexbg free_clusters count
jbd2: fix use after free in jbd2_journal_dirty_metadata()
ext4: reserve metadata block for every delayed write
ext4: update reserved space after the 'correction'
ext4: do not use yield()
ext4: remove unused variable in ext4_free_blocks()
ext4: fix WARN_ON from ext4_releasepage()
ext4: fix the wrong number of the allocated blocks in ext4_split_extent()
ext4: update extent status tree after an extent is zeroed out
ext4: fix wrong m_len value after unwritten extent conversion
ext4: add self-testing infrastructure to do a sanity check
ext4: avoid a potential overflow in ext4_es_can_be_merged()
ext4: invalidate extent status tree during extent migration
ext4: remove unnecessary wait for extent conversion in ext4_fallocate()
ext4: add warning to ext4_convert_unwritten_extents_endio
ext4: disable merging of uninitialized extents
...
In data=journal mode, if we unmount the file system before a
transaction has a chance to complete, when the journal inode is being
evicted, we can end up calling into jbd2_log_wait_commit() for the
last transaction, after the journalling machinery has been shut down.
Arguably we should adjust ext4_should_journal_data() to return FALSE
for the journal inode, but the only place it matters is
ext4_evict_inode(), and so to save a bit of CPU time, and to make the
patch much more obviously correct by inspection(tm), we'll fix it by
explicitly not trying to waiting for a journal commit when we are
evicting the journal inode, since it's guaranteed to never succeed in
this case.
This can be easily replicated via:
mount -t ext4 -o data=journal /dev/vdb /vdb ; umount /vdb
------------[ cut here ]------------
WARNING: at /usr/projects/linux/ext4/fs/jbd2/journal.c:542 __jbd2_log_start_commit+0xba/0xcd()
Hardware name: Bochs
JBD2: bad log_start_commit: 3005630206 3005630206 0 0
Modules linked in:
Pid: 2909, comm: umount Not tainted 3.8.0-rc3 #1020
Call Trace:
[<c015c0ef>] warn_slowpath_common+0x68/0x7d
[<c02b7e7d>] ? __jbd2_log_start_commit+0xba/0xcd
[<c015c177>] warn_slowpath_fmt+0x2b/0x2f
[<c02b7e7d>] __jbd2_log_start_commit+0xba/0xcd
[<c02b8075>] jbd2_log_start_commit+0x24/0x34
[<c0279ed5>] ext4_evict_inode+0x71/0x2e3
[<c021f0ec>] evict+0x94/0x135
[<c021f9aa>] iput+0x10a/0x110
[<c02b7836>] jbd2_journal_destroy+0x190/0x1ce
[<c0175284>] ? bit_waitqueue+0x50/0x50
[<c028d23f>] ext4_put_super+0x52/0x294
[<c020efe3>] generic_shutdown_super+0x48/0xb4
[<c020f071>] kill_block_super+0x22/0x60
[<c020f3e0>] deactivate_locked_super+0x22/0x49
[<c020f5d6>] deactivate_super+0x30/0x33
[<c0222795>] mntput_no_expire+0x107/0x10c
[<c02233a7>] sys_umount+0x2cf/0x2e0
[<c02233ca>] sys_oldumount+0x12/0x14
[<c08096b8>] syscall_call+0x7/0xb
---[ end trace 6a954cc790501c1f ]---
jbd2_log_wait_commit: error: j_commit_request=-1289337090, tid=0
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@vger.kernel.org
Commit 84c17543ab (ext4: move work from io_end to inode) triggered a
regression when running xfstest #270 when the file system is mounted
with dioread_nolock.
The problem is that after ext4_evict_inode() calls ext4_ioend_wait(),
this guarantees that last io_end structure has been freed, but it does
not guarantee that the workqueue structure, which was moved into the
inode by commit 84c17543ab, is actually finished. Once
ext4_flush_completed_IO() calls ext4_free_io_end() on CPU #1, this
will allow ext4_ioend_wait() to return on CPU #2, at which point the
evict_inode() codepath can race against the workqueue code on CPU #1
accessing EXT4_I(inode)->i_unwritten_work to find the next item of
work to do.
Fix this by calling cancel_work_sync() in ext4_ioend_wait(), which
will be renamed ext4_ioend_shutdown(), since it is only used by
ext4_evict_inode(). Also, move the call to ext4_ioend_shutdown()
until after truncate_inode_pages() and filemap_write_and_wait() are
called, to make sure all dirty pages have been written back and
flushed from the page cache first.
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<c01dda6a>] cwq_activate_delayed_work+0x3b/0x7e
*pdpt = 0000000030bc3001 *pde = 0000000000000000
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
Modules linked in:
Pid: 6, comm: kworker/u:0 Not tainted 3.8.0-rc3-00013-g84c1754-dirty #91 Bochs Bochs
EIP: 0060:[<c01dda6a>] EFLAGS: 00010046 CPU: 0
EIP is at cwq_activate_delayed_work+0x3b/0x7e
EAX: 00000000 EBX: 00000000 ECX: f505fe54 EDX: 00000000
ESI: ed5b697c EDI: 00000006 EBP: f64b7e8c ESP: f64b7e84
DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
CR0: 8005003b CR2: 00000000 CR3: 30bc2000 CR4: 000006f0
DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
DR6: ffff0ff0 DR7: 00000400
Process kworker/u:0 (pid: 6, ti=f64b6000 task=f64b4160 task.ti=f64b6000)
Stack:
f505fe00 00000006 f64b7e9c c01de3d7 f6435540 00000003 f64b7efc c01def1d
f6435540 00000002 00000000 0000008a c16d0808 c040a10b c16d07d8 c16d08b0
f505fe00 c16d0780 00000000 00000000 ee153df4 c1ce4a30 c17d0e30 00000000
Call Trace:
[<c01de3d7>] cwq_dec_nr_in_flight+0x71/0xfb
[<c01def1d>] process_one_work+0x5d8/0x637
[<c040a10b>] ? ext4_end_bio+0x300/0x300
[<c01e3105>] worker_thread+0x249/0x3ef
[<c01ea317>] kthread+0xd8/0xeb
[<c01e2ebc>] ? manage_workers+0x4bb/0x4bb
[<c023a370>] ? trace_hardirqs_on+0x27/0x37
[<c0f1b4b7>] ret_from_kernel_thread+0x1b/0x28
[<c01ea23f>] ? __init_kthread_worker+0x71/0x71
Code: 01 83 15 ac ff 6c c1 00 31 db 89 c6 8b 00 a8 04 74 12 89 c3 30 db 83 05 b0 ff 6c c1 01 83 15 b4 ff 6c c1 00 89 f0 e8 42 ff ff ff <8b> 13 89 f0 83 05 b8 ff 6c c1
6c c1 00 31 c9 83
EIP: [<c01dda6a>] cwq_activate_delayed_work+0x3b/0x7e SS:ESP 0068:f64b7e84
CR2: 0000000000000000
---[ end trace a1923229da53d8a4 ]---
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
Regression was introduced by following commit 8c854473
TESTCASE (git://oss.sgi.com/xfs/cmds/xfstests.git):
#while true;do ./check 301 || break ;done
Also fix potential memory leakage in get_ext_path() once
ext4_ext_find_extent() have failed.
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
I had assumed that the only use of module aliases for filesystems
prior to "fs: Limit sys_mount to only request filesystem modules."
was in request_module. It turns out I was wrong. At least mkinitcpio
in Arch linux uses these aliases.
So readd the preexising aliases, to keep from breaking userspace.
Userspace eventually will have to follow and use the same aliases the
kernel does. So at some point we may be delete these aliases without
problems. However that day is not today.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Currently when converting extent to initialized, we have to decide
whether to zeroout part/all of the uninitialized extent in order to
avoid extent tree growing rapidly.
The decision is made by comparing the size of the extent with the
configurable value s_extent_max_zeroout_kb which is in kibibytes units.
However when converting it to number of blocks we currently use it as it
was in bytes. This is obviously bug and it will result in ext4 _never_
zeroout extents, but rather always split and convert parts to
initialized while leaving the rest uninitialized in default setting.
Fix this by using s_extent_max_zeroout_kb as kibibytes.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
A user who was using a 8TB+ file system and with a very large flexbg
size (> 65536) could cause the atomic_t used in the struct flex_groups
to overflow. This was detected by PaX security patchset:
http://forums.grsecurity.net/viewtopic.php?f=3&t=3289&p=12551#p12551
This bug was introduced in commit 9f24e4208f, so it's been around
since 2.6.30. :-(
Fix this by using an atomic64_t for struct orlav_stats's
free_clusters.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Cc: stable@vger.kernel.org
Currently we only reserve space (data+metadata) in delayed allocation if
we're allocating from new cluster (which is always in non-bigalloc file
system) which is ok for data blocks, because we reserve the whole cluster.
However we have to reserve metadata for every delayed block we're going
to write because every block could potentially require metedata block
when we need to grow the extent tree.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Currently in ext4_ext_map_blocks() in delayed allocation writeback
we would update the reservation and after that check whether we claimed
cluster outside of the range of the allocation and if so, we'll give the
block back to the reservation pool.
However this also means that if the number of reserved data block
dropped to zero before the correction, we would release all the metadata
reservation as well, however we might still need it because the we're
not done with the delayed allocation and there might be more blocks to
come. This will result in error messages such as:
EXT4-fs warning (device sdb): ext4_da_update_reserve_space:361: ino 12,
allocated 1 with only 0 reserved metadata blocks (releasing 1 blocks
with reserved 1 data blocks)
This will only happen on bigalloc file system and it can be easily
reproduced using fiemap-tester from xfstests like this:
./src/fiemap-tester -m DHDHDHDHD -S -p0 /mnt/test/file
Or using xfstests such as 225.
Fix this by doing the correction first and updating the reservation
after that so that we do not accidentally decrease
i_reserved_data_blocks to zero.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Using yield() is strongly discouraged (see sched/core.c) especially
since we can just use cond_resched().
Replace all use of yield() with cond_resched().
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4_releasepage() warns when it is passed a page with PageChecked set.
However this can correctly happen when invalidate_inode_pages2_range()
invalidates pages - and we should fail the release in that case. Since
the page was dirty anyway, it won't be discarded and no harm has
happened but it's good to be safe. Also remove bogus page_has_buffers()
check - we are guaranteed page has buffers in this function.
Reported-by: Zheng Liu <gnehzuil.liu@gmail.com>
Tested-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit fixes a wrong return value of the number of the allocated
blocks in ext4_split_extent. When the length of blocks we want to
allocate is greater than the length of the current extent, we return a
wrong number. Let's see what happens in the following case when we
call ext4_split_extent().
map: [48, 72]
ex: [32, 64, u]
'ex' will be split into two parts:
ex1: [32, 47, u]
ex2: [48, 64, w]
'map->m_len' is returned from this function, and the value is 24. But
the real length is 16. So it should be fixed.
Meanwhile in this commit we use right length of the allocated blocks
when get_reserved_cluster_alloc in ext4_ext_handle_uninitialized_extents
is called.
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Dmitry Monakhov <dmonakhov@openvz.org>
Cc: stable@vger.kernel.org
When we try to split an extent, this extent could be zeroed out and mark
as initialized. But we don't know this in ext4_map_blocks because it
only returns a length of allocated extent. Meanwhile we will mark this
extent as uninitialized because we only check m_flags.
This commit update extent status tree when we try to split an unwritten
extent. We don't need to worry about the status of this extent because
we always mark it as initialized.
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Dmitry Monakhov <dmonakhov@openvz.org>
The ext4_ext_handle_uninitialized_extents() function was assuming the
return value of ext4_ext_map_blocks() is equal to map->m_len. This
incorrect assumption was harmless until we started use status tree as
a extent cache because we need to update status tree according to
'm_len' value.
Meanwhile this commit marks EXT4_MAP_MAPPED flag after unwritten extent
conversion. It shouldn't cause a bug because we update status tree
according to checking EXT4_MAP_UNWRITTEN flag. But it should be fixed.
After applied this commit, the following error message from self-testing
infrastructure disappears.
...
kernel: ES len assertation failed for inode: 230 retval 1 !=
map->m_len 3 in ext4_map_blocks (allocation)
...
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Dmitry Monakhov <dmonakhov@openvz.org>
This commit adds a self-testing infrastructure like extent tree does to
do a sanity check for extent status tree. After status tree is as a
extent cache, we'd better to make sure that it caches right result.
After applied this commit, we will get a lot of messages when we run
xfstests as below.
...
kernel: ES len assertation failed for inode: 230 retval 1 != map->m_len
3 in ext4_map_blocks (allocation)
...
kernel: ES cache assertation failed for inode: 230 es_cached ex
[974/2/4781/20] != found ex [974/1/4781/1000]
...
kernel: ES insert assertation failed for inode: 635 ex_status
[0/45/21388/w] != es_status [44/1/21432/u]
...
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Check the length of an extent to avoid a potential overflow in
ext4_es_can_be_merged().
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Dmitry Monakhov <dmonakhov@openvz.org>
mext_replace_branches() will change inode's extents layout so
we have to drop corresponding cache.
TESTCASE: 301'th xfstest was not yet accepted to official xfstest's branch
and can be found here: 7b7efeee30
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Now that we don't merge uninitialized extents anymore,
ext4_fallocate() is free to operate on the inode while there are still
some extent conversions pending - it won't disturb them in any way.
Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Reviewed-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Splitting extents inside endio is a bad thing, but unfortunately it is
still possible. In fact we are pretty close to the moment when all
related issues will be fixed. Let's warn developer if it still the
case.
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Derived from Jan's patch:http://permalink.gmane.org/gmane.comp.file-systems.ext4/36470
Merging of uninitialized extents creates all sorts of interesting race
possibilities when writeback / DIO races with fallocate. Thus
ext4_convert_unwritten_extents_endio() has to deal with a case where
extent to be converted needs to be split out first. That isn't nice
for two reasons:
1) It may need allocation of extent tree block so ENOSPC is possible.
2) It complicates end_io handling code
So we disable merging of uninitialized extents which allows us to simplify
the code. Extents will get merged after they are converted to initialized
ones.
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
When ext4_split_extent_at() ends up doing zeroout & conversion to
initialized instead of split & conversion, ext4_split_extent() gets
confused and can wrongly mark the extent back as uninitialized
resulting in end IO code getting confused from large unwritten extents
and may result in data loss.
The example of problematic behavior is:
lblk len lblk len
ext4_split_extent() (ex=[1000,30,uninit], map=[1010,10])
ext4_split_extent_at() (split [1000,30,uninit] at 1020)
ext4_ext_insert_extent() -> ENOSPC
ext4_ext_zeroout()
-> extent [1000,30] is now initialized
ext4_split_extent_at() (split [1000,30,init] at 1010,
MARK_UNINIT1 | MARK_UNINIT2)
-> extent is split and parts marked as uninitialized
Fix the problem by rechecking extent type after the first
ext4_split_extent_at() returns. None of split_flags can not be applied
to initialized extent so this patch also add BUG_ON to prevent similar
issues in future.
TESTCASE: b8a55eb5ce
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Modify the request_module to prefix the file system type with "fs-"
and add aliases to all of the filesystems that can be built as modules
to match.
A common practice is to build all of the kernel code and leave code
that is not commonly needed as modules, with the result that many
users are exposed to any bug anywhere in the kernel.
Looking for filesystems with a fs- prefix limits the pool of possible
modules that can be loaded by mount to just filesystems trivially
making things safer with no real cost.
Using aliases means user space can control the policy of which
filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
with blacklist and alias directives. Allowing simple, safe,
well understood work-arounds to known problematic software.
This also addresses a rare but unfortunate problem where the filesystem
name is not the same as it's module name and module auto-loading
would not work. While writing this patch I saw a handful of such
cases. The most significant being autofs that lives in the module
autofs4.
This is relevant to user namespaces because we can reach the request
module in get_fs_type() without having any special permissions, and
people get uncomfortable when a user specified string (in this case
the filesystem type) goes all of the way to request_module.
After having looked at this issue I don't think there is any
particular reason to perform any filtering or permission checks beyond
making it clear in the module request that we want a filesystem
module. The common pattern in the kernel is to call request_module()
without regards to the users permissions. In general all a filesystem
module does once loaded is call register_filesystem() and go to sleep.
Which means there is not much attack surface exposed by loading a
filesytem module unless the filesystem is mounted. In a user
namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
which most filesystems do not set today.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reported-by: Kees Cook <keescook@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull more VFS bits from Al Viro:
"Unfortunately, it looks like xattr series will have to wait until the
next cycle ;-/
This pile contains 9p cleanups and fixes (races in v9fs_fid_add()
etc), fixup for nommu breakage in shmem.c, several cleanups and a bit
more file_inode() work"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
constify path_get/path_put and fs_struct.c stuff
fix nommu breakage in shmem.c
cache the value of file_inode() in struct file
9p: if v9fs_fid_lookup() gets to asking server, it'd better have hashed dentry
9p: make sure ->lookup() adds fid to the right dentry
9p: untangle ->lookup() a bit
9p: double iput() in ->lookup() if d_materialise_unique() fails
9p: v9fs_fid_add() can't fail now
v9fs: get rid of v9fs_dentry
9p: turn fid->dlist into hlist
9p: don't bother with private lock in ->d_fsdata; dentry->d_lock will do just fine
more file_inode() open-coded instances
selinux: opened file can't have NULL or negative ->f_path.dentry
(In the meantime, the hlist traversal macros have changed, so this
required a semantic conflict fixup for the newly hlistified fid->dlist)
