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
The following race is possible:
[kjournald2] other_task
jbd2_journal_commit_transaction()
j_state = T_FINISHED;
spin_unlock(&journal->j_list_lock);
->jbd2_journal_remove_checkpoint()
->jbd2_journal_free_transaction();
->kmem_cache_free(transaction)
->j_commit_callback(journal, transaction);
-> USE_AFTER_FREE
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
In order to demonstrace this issue one should mount ext4 with mount -o
discard option on SSD disk. This makes callback longer and race
window becomes wider.
In order to fix this we should mark transaction as finished only after
callbacks have completed
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
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>
Pull btrfs fixes from Chris Mason:
"We've had a busy two weeks of bug fixing. The biggest patches in here
are some long standing early-enospc problems (Josef) and a very old
race where compression and mmap combine forces to lose writes (me).
I'm fairly sure the mmap bug goes all the way back to the introduction
of the compression code, which is proof that fsx doesn't trigger every
possible mmap corner after all.
I'm sure you'll notice one of these is from this morning, it's a small
and isolated use-after-free fix in our scrub error reporting. I
double checked it here."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: don't drop path when printing out tree errors in scrub
Btrfs: fix wrong return value of btrfs_lookup_csum()
Btrfs: fix wrong reservation of csums
Btrfs: fix double free in the btrfs_qgroup_account_ref()
Btrfs: limit the global reserve to 512mb
Btrfs: hold the ordered operations mutex when waiting on ordered extents
Btrfs: fix space accounting for unlink and rename
Btrfs: fix space leak when we fail to reserve metadata space
Btrfs: fix EIO from btrfs send in is_extent_unchanged for punched holes
Btrfs: fix race between mmap writes and compression
Btrfs: fix memory leak in btrfs_create_tree()
Btrfs: fix locking on ROOT_REPLACE operations in tree mod log
Btrfs: fix missing qgroup reservation before fallocating
Btrfs: handle a bogus chunk tree nicely
Btrfs: update to use fs_state bit
A user reported a panic where we were panicing somewhere in
tree_backref_for_extent from scrub_print_warning. He only captured the trace
but looking at scrub_print_warning we drop the path right before we mess with
the extent buffer to print out a bunch of stuff, which isn't right. So fix this
by dropping the path after we use the eb if we need to. Thanks,
Cc: stable@vger.kernel.org
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Here are two fixes for sysfs that resolve issues that have been found by the
Trinity fuzz tool, causing oopses in sysfs. They both have been in linux-next
for a while to ensure that they do not cause any other problems.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull sysfs fixes from Greg Kroah-Hartman:
"Here are two fixes for sysfs that resolve issues that have been found
by the Trinity fuzz tool, causing oopses in sysfs. They both have
been in linux-next for a while to ensure that they do not cause any
other problems."
* tag 'driver-core-3.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
sysfs: handle failure path correctly for readdir()
sysfs: fix race between readdir and lseek
Pull userns fixes from Eric W Biederman:
"The bulk of the changes are fixing the worst consequences of the user
namespace design oversight in not considering what happens when one
namespace starts off as a clone of another namespace, as happens with
the mount namespace.
The rest of the changes are just plain bug fixes.
Many thanks to Andy Lutomirski for pointing out many of these issues."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
userns: Restrict when proc and sysfs can be mounted
ipc: Restrict mounting the mqueue filesystem
vfs: Carefully propogate mounts across user namespaces
vfs: Add a mount flag to lock read only bind mounts
userns: Don't allow creation if the user is chrooted
yama: Better permission check for ptraceme
pid: Handle the exit of a multi-threaded init.
scm: Require CAP_SYS_ADMIN over the current pidns to spoof pids.
If we don't find the expected csum item, but find a csum item which is
adjacent to the specified extent, we should return -EFBIG, or we should
return -ENOENT. But btrfs_lookup_csum() return -EFBIG even the csum item
is not adjacent to the specified extent. Fix it.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
We reserve the space for csums only when we write data into a file, in
the other cases, such as tree log, log replay, we don't do reservation,
so we can use the reservation of the transaction handle just for the former.
And for the latter, we should use the tree's own reservation. But the
function - btrfs_csum_file_blocks() didn't differentiate between these
two types of the cases, fix it.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
The function btrfs_find_all_roots is responsible to allocate
memory for 'roots' and free it if errors happen,so the caller should not
free it again since the work has been done.
Besides,'tmp' is allocated after the function btrfs_find_all_roots,
so we can return directly if btrfs_find_all_roots() fails.
Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
A user reported a problem where he was getting early ENOSPC with hundreds of
gigs of free data space and 6 gigs of free metadata space. This is because the
global block reserve was taking up the entire free metadata space. This is
ridiculous, we have infrastructure in place to throttle if we start using too
much of the global reserve, so instead of letting it get this huge just limit it
to 512mb so that users can still get work done. This allowed the user to
complete his rsync without issues. Thanks
Cc: stable@vger.kernel.org
Reported-and-tested-by: Stefan Priebe <s.priebe@profihost.ag>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
We need to hold the ordered_operations mutex while waiting on ordered extents
since we splice and run the ordered extents list. We need to make sure anybody
else who wants to wait on ordered extents does actually wait for them to be
completed. This will keep us from bailing out of flushing in case somebody is
already waiting on ordered extents to complete. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
We are way over-reserving for unlink and rename. Rename is just some random
huge number and unlink accounts for tree log operations that don't actually
happen during unlink, not to mention the tree log doesn't take from the trans
block rsv anyway so it's completely useless. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Dave reported a warning when running xfstest 275. We have been leaking delalloc
metadata space when our reservations fail. This is because we were improperly
calculating how much space to free for our checksum reservations. The problem
is we would sometimes free up space that had already been freed in another
thread and we would end up with negative usage for the delalloc space. This
patch fixes the problem by calculating how much space the other threads would
have already freed, and then calculate how much space we need to free had we not
done the reservation at all, and then freeing any excess space. This makes
xfstests 275 no longer have leaked space. Thanks
Cc: stable@vger.kernel.org
Reported-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
When you take a snapshot, punch a hole where there has been data, then take
another snapshot and try to send an incremental stream, btrfs send would
give you EIO. That is because is_extent_unchanged had no support for holes
being punched. With this patch, instead of returning EIO we just return
0 (== the extent is not unchanged) and we're good.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Cc: Alexander Block <ablock84@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Commit 06ae43f34b ("Don't bother with redoing rw_verify_area() from
default_file_splice_from()") lost the checks to test existence of the
write/aio_write methods. My apologies ;-/
Eventually, we want that in fs/splice.c side of things (no point
repeating it for every buffer, after all), but for now this is the
obvious minimal fix.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Only allow unprivileged mounts of proc and sysfs if they are already
mounted when the user namespace is created.
proc and sysfs are interesting because they have content that is
per namespace, and so fresh mounts are needed when new namespaces
are created while at the same time proc and sysfs have content that
is shared between every instance.
Respect the policy of who may see the shared content of proc and sysfs
by only allowing new mounts if there was an existing mount at the time
the user namespace was created.
In practice there are only two interesting cases: proc and sysfs are
mounted at their usual places, proc and sysfs are not mounted at all
(some form of mount namespace jail).
Cc: stable@vger.kernel.org
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
As a matter of policy MNT_READONLY should not be changable if the
original mounter had more privileges than creator of the mount
namespace.
Add the flag CL_UNPRIVILEGED to note when we are copying a mount from
a mount namespace that requires more privileges to a mount namespace
that requires fewer privileges.
When the CL_UNPRIVILEGED flag is set cause clone_mnt to set MNT_NO_REMOUNT
if any of the mnt flags that should never be changed are set.
This protects both mount propagation and the initial creation of a less
privileged mount namespace.
Cc: stable@vger.kernel.org
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
When a read-only bind mount is copied from mount namespace in a higher
privileged user namespace to a mount namespace in a lesser privileged
user namespace, it should not be possible to remove the the read-only
restriction.
Add a MNT_LOCK_READONLY mount flag to indicate that a mount must
remain read-only.
CC: stable@vger.kernel.org
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Guarantee that the policy of which files may be access that is
established by setting the root directory will not be violated
by user namespaces by verifying that the root directory points
to the root of the mount namespace at the time of user namespace
creation.
Changing the root is a privileged operation, and as a matter of policy
it serves to limit unprivileged processes to files below the current
root directory.
For reasons of simplicity and comprehensibility the privilege to
change the root directory is gated solely on the CAP_SYS_CHROOT
capability in the user namespace. Therefore when creating a user
namespace we must ensure that the policy of which files may be access
can not be violated by changing the root directory.
Anyone who runs a processes in a chroot and would like to use user
namespace can setup the same view of filesystems with a mount
namespace instead. With this result that this is not a practical
limitation for using user namespaces.
Cc: stable@vger.kernel.org
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull vfs fixes from Al Viro:
"stable fodder; assorted deadlock fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vt: synchronize_rcu() under spinlock is not nice...
Nest rename_lock inside vfsmount_lock
Don't bother with redoing rw_verify_area() from default_file_splice_from()
... lest we get livelocks between path_is_under() and d_path() and friends.
The thing is, wrt fairness lglocks are more similar to rwsems than to rwlocks;
it is possible to have thread B spin on attempt to take lock shared while thread
A is already holding it shared, if B is on lower-numbered CPU than A and there's
a thread C spinning on attempt to take the same lock exclusive.
As the result, we need consistent ordering between vfsmount_lock (lglock) and
rename_lock (seq_lock), even though everything that takes both is going to take
vfsmount_lock only shared.
Spotted-by: Brad Spengler <spender@grsecurity.net>
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
- Fix an NFSv4 idmapper regression
- Fix an Oops in the pNFS blocks client
- Fix up various issues with pNFS layoutcommit
- Ensure correct read ordering of variables in rpc_wake_up_task_queue_locked
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Merge tag 'nfs-for-3.9-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
Pull NFS client bugfixes from Trond Myklebust:
- Fix an NFSv4 idmapper regression
- Fix an Oops in the pNFS blocks client
- Fix up various issues with pNFS layoutcommit
- Ensure correct read ordering of variables in
rpc_wake_up_task_queue_locked
* tag 'nfs-for-3.9-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
SUNRPC: Add barriers to ensure read ordering in rpc_wake_up_task_queue_locked
NFSv4.1: Add a helper pnfs_commit_and_return_layout
NFSv4.1: Always clear the NFS_INO_LAYOUTCOMMIT in layoutreturn
NFSv4.1: Fix a race in pNFS layoutcommit
pnfs-block: removing DM device maybe cause oops when call dev_remove
NFSv4: Fix the string length returned by the idmapper
Btrfs uses page_mkwrite to ensure stable pages during
crc calculations and mmap workloads. We call clear_page_dirty_for_io
before we do any crcs, and this forces any application with the file
mapped to wait for the crc to finish before it is allowed to change
the file.
With compression on, the clear_page_dirty_for_io step is happening after
we've compressed the pages. This means the applications might be
changing the pages while we are compressing them, and some of those
modifications might not hit the disk.
This commit adds the clear_page_dirty_for_io before compression starts
and makes sure to redirty the page if we have to fallback to
uncompressed IO as well.
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Reported-by: Alexandre Oliva <oliva@gnu.org>
cc: stable@vger.kernel.org
