Currently this function is always called with the object id of the root
key of the chunk_tree, which is always BTRFS_CHUNK_TREE_OBJECTID. So
let's subsume it straight into the function itself. No functional
change.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
THe function is always called with chunk_objectid set to
BTRFS_FIRST_CHUNK_TREE_OBJECTID. Let's collapse the parameter in the
function itself. No functional changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Every shared ref has a parent tree block, which can be get from
btrfs_extent_inline_ref_offset(). And the tree block must be aligned
to the nodesize, so we'd know this inline ref is not valid if this
block's bytenr is not aligned to the nodesize, in which case, most
likely the ref type has been misused.
This adds the above mentioned check and also updates
print_extent_item() called by btrfs_print_leaf() to point out the
invalid ref while printing the tree structure.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The BUG_ON() can be triggered when the caller is processing an invalid
extent inline ref, e.g.
a shared data ref is offered instead of an extent data ref, such that
it tries to find a non-existent tree block and then btrfs_search_slot
returns 1 for no such item.
This replaces the BUG_ON() with a WARN() followed by calling
btrfs_print_leaf() to show more details about what's going on and
returning -EINVAL to upper callers.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we have a helper to report invalid value of extent inline ref
type, we need to quit gracefully instead of throwing out a kernel panic.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_print_leaf() is used in btrfs_get_extent_inline_ref_type, so
here we really want to print the invalid value of ref type instead of
causing a kernel panic.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that btrfs_get_extent_inline_ref_type() can report if type is a
valid one and all callers can gracefully deal with that, we don't need
to crash here.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since we have a helper which can do sanity check, this converts all
btrfs_extent_inline_ref_type to it.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
An invalid value of extent inline ref type may be read from a
malicious image which may force btrfs to crash.
This adds a helper which does sanity check for the ref type, so we can
know if it's sane, return he type, otherwise return an error.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minimal tweak const types, causing warnings due to other cleanup patches ]
Signed-off-by: David Sterba <dsterba@suse.com>
flush_all_writes is an atomic but does not use the semantics at all,
it's just on/off indicator, we can use bool.
Signed-off-by: David Sterba <dsterba@suse.com>
When changing a file's acl mask, btrfs_set_acl() will first set the
group bits of i_mode to the value of the mask, and only then set the
actual extended attribute representing the new acl.
If the second part fails (due to lack of space, for example) and the
file had no acl attribute to begin with, the system will from now on
assume that the mask permission bits are actual group permission bits,
potentially granting access to the wrong users.
Prevent this by restoring the original mode bits if __btrfs_set_acl
fails.
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
BTRFS_FIRST_CHUNK_TREE_OBJECTIS id the only objectid being used in the
chunk_tree. So remove a variable which is always set to that value and collapse
its usage in callees which are passed this variable. No functional changes
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_make_block_group is always called with chunk_objectid set to
BTRFS_FIRST_CHUNK_TREE_OBJECTID. There's no reason why this behavior will
change anytime soon, so let's remove the argument and decrease the cognitive
load when reading the code path. No functional change
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need for the extra pair of parentheses, remove it. This
fixes the following warning when building with clang:
fs/btrfs/tree-log.c:3694:10: warning: equality comparison with extraneous
parentheses [-Wparentheses-equality]
if ((i == (nr - 1)))
~~^~~~~~~~~~~
Also remove the unnecessary parentheses around the substraction.
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_alloc_dev_extent currently unconditionally sets the uuid in the
leaf block header the function is working with. This is unnecessary
since this operation is peformed by the core btree handling code
(splitting a node, allocating a new btree block etc). So let's remove
it.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This patch provides a band aid to improve the 'out of the box'
behaviour of btrfs for disks that are detected as being an ssd. In a
general purpose mixed workload scenario, the current ssd mode causes
overallocation of available raw disk space for data, while leaving
behind increasing amounts of unused fragmented free space. This
situation leads to early ENOSPC problems which are harming user
experience and adoption of btrfs as a general purpose filesystem.
This patch modifies the data extent allocation behaviour of the ssd mode
to make it behave identical to nossd mode. The metadata behaviour and
additional ssd_spread option stay untouched so far.
Recommendations for future development are to reconsider the current
oversimplified nossd / ssd distinction and the broken detection
mechanism based on the rotational attribute in sysfs and provide
experienced users with a more flexible way to choose allocator behaviour
for data and metadata, optimized for certain use cases, while keeping
sane 'out of the box' default settings. The internals of the current
btrfs code have more potential than what currently gets exposed to the
user to choose from.
The SSD story...
In the first year of btrfs development, around early 2008, btrfs
gained a mount option which enables specific functionality for
filesystems on solid state devices. The first occurance of this
functionality is in commit e18e4809, labeled "Add mount -o ssd, which
includes optimizations for seek free storage".
The effect on allocating free space for doing (data) writes is to
'cluster' writes together, writing them out in contiguous space, as
opposed to a 'tetris' way of putting all separate writes into any free
space fragment that fits (which is what the -o nossd behaviour does).
A somewhat simplified explanation of what happens is that, when for
example, the 'cluster' size is set to 2MiB, when we do some writes, the
data allocator will search for a free space block that is 2MiB big, and
put the writes in there. The ssd mode itself might allow a 2MiB cluster
to be composed of multiple free space extents with some existing data in
between, while the additional ssd_spread mount option kills off this
option and requires fully free space.
The idea behind this is (commit 536ac8ae): "The [...] clusters make it
more likely a given IO will completely overwrite the ssd block, so it
doesn't have to do an internal rwm cycle."; ssd block meaning nand erase
block. So, effectively this means applying a "locality based algorithm"
and trying to outsmart the actual ssd.
Since then, various changes have been made to the involved code, but the
basic idea is still present, and gets activated whenever the ssd mount
option is active. This also happens by default, when the rotational flag
as seen at /sys/block/<device>/queue/rotational is set to 0.
However, there's a number of problems with this approach.
First, what the optimization is trying to do is outsmart the ssd by
assuming there is a relation between the physical address space of the
block device as seen by btrfs and the actual physical storage of the
ssd, and then adjusting data placement. However, since the introduction
of the Flash Translation Layer (FTL) which is a part of the internal
controller of an ssd, these attempts are futile. The use of good quality
FTL in consumer ssd products might have been limited in 2008, but this
situation has changed drastically soon after that time. Today, even the
flash memory in your automatic cat feeding machine or your grandma's
wheelchair has a full featured one.
Second, the behaviour as described above results in the filesystem being
filled up with badly fragmented free space extents because of relatively
small pieces of space that are freed up by deletes, but not selected
again as part of a 'cluster'. Since the algorithm prefers allocating a
new chunk over going back to tetris mode, the end result is a filesystem
in which all raw space is allocated, but which is composed of
underutilized chunks with a 'shotgun blast' pattern of fragmented free
space. Usually, the next problematic thing that happens is the
filesystem wanting to allocate new space for metadata, which causes the
filesystem to fail in spectacular ways.
Third, the default mount options you get for an ssd ('ssd' mode enabled,
'discard' not enabled), in combination with spreading out writes over
the full address space and ignoring freed up space leads to worst case
behaviour in providing information to the ssd itself, since it will
never learn that all the free space left behind is actually free. There
are two ways to let an ssd know previously written data does not have to
be preserved, which are sending explicit signals using discard or
fstrim, or by simply overwriting the space with new data. The worst
case behaviour is the btrfs ssd_spread mount option in combination with
not having discard enabled. It has a side effect of minimizing the reuse
of free space previously written in.
Fourth, the rotational flag in /sys/ does not reliably indicate if the
device is a locally attached ssd. For example, iSCSI or NBD displays as
non-rotational, while a loop device on an ssd shows up as rotational.
The combination of the second and third problem effectively means that
despite all the good intentions, the btrfs ssd mode reliably causes the
ssd hardware and the filesystem structures and performance to be choked
to death. The clickbait version of the title of this story would have
been "Btrfs ssd optimizations considered harmful for ssds".
The current nossd 'tetris' mode (even still without discard) allows a
pattern of overwriting much more previously used space, causing many
more implicit discards to happen because of the overwrite information
the ssd gets. The actual location in the physical address space, as seen
from the point of view of btrfs is irrelevant, because the actual writes
to the low level flash are reordered anyway thanks to the FTL.
Changes made in the code
1. Make ssd mode data allocation identical to tetris mode, like nossd.
2. Adjust and clean up filesystem mount messages so that we can easily
identify if a kernel has this patch applied or not, when providing
support to end users. Also, make better use of the *_and_info helpers to
only trigger messages on actual state changes.
Backporting notes
Notes for whoever wants to backport this patch to their 4.9 LTS kernel:
* First apply commit 951e7966 "btrfs: drop the nossd flag when
remounting with -o ssd", or fixup the differences manually.
* The rest of the conflicts are because of the fs_info refactoring. So,
for example, instead of using fs_info, it's root->fs_info in
extent-tree.c
Signed-off-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Although this bio has no data attached, it will reach this condition
(bio->bi_opf & REQ_PREFLUSH) and then update the flush_gen of dev_state
in __btrfsic_submit_bio. So we should still submit it through integrity
checker. Otherwise, the integrity checker will throw the following warning
when I mount a newly created btrfs filesystem.
[10264.755497] btrfs: attempt to write superblock which references block M @29523968 (sdb1/1111654400/0) which is not flushed out of disk's write cache (block flush_gen=1, dev->flush_gen=0)!
[10264.755498] btrfs: attempt to write superblock which references block M @29523968 (sdb1/37912576/0) which is not flushed out of disk's write cache (block flush_gen=1, dev->flush_gen=0)!
Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When doing an incremental send it's possible that the computed send stream
contains clone operations that will fail on the receiver if the receiver
has compression enabled and the clone operations target a sector sized
extent that starts at a zero file offset, is not compressed on the source
filesystem but ends up being compressed and inlined at the destination
filesystem.
Example scenario:
$ mkfs.btrfs -f /dev/sdb
$ mount -o compress /dev/sdb /mnt
# By doing a direct IO write, the data is not compressed.
$ xfs_io -f -d -c "pwrite -S 0xab 0 4K" /mnt/foobar
$ btrfs subvolume snapshot -r /mnt /mnt/mysnap1
$ xfs_io -c "reflink /mnt/foobar 0 8K 4K" /mnt/foobar
$ btrfs subvolume snapshot -r /mnt /mnt/mysnap2
$ btrfs send -f /tmp/1.snap /mnt/mysnap1
$ btrfs send -f /tmp/2.snap -p /mnt/mysnap1 /mnt/mysnap2
$ umount /mnt
$ mkfs.btrfs -f /dev/sdc
$ mount -o compress /dev/sdc /mnt
$ btrfs receive -f /tmp/1.snap /mnt
$ btrfs receive -f /tmp/2.snap /mnt
ERROR: failed to clone extents to foobar
Operation not supported
The same could be achieved by mounting the source filesystem without
compression and doing a buffered IO write instead of a direct IO one,
and mounting the destination filesystem with compression enabled.
So fix this by issuing regular write operations in the send stream
instead of clone operations when the source offset is zero and the
range has a length matching the sector size.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is a corner case that slips through the checkers in functions
reading extent buffer, ie.
if (start < eb->len) and (start + len > eb->len),
then
a) map_private_extent_buffer() returns immediately because
it's thinking the range spans across two pages,
b) and the checkers in read_extent_buffer(), WARN_ON(start > eb->len)
and WARN_ON(start + len > eb->start + eb->len), both are OK in this
corner case, but it'd actually try to access the eb->pages out of
bounds because of (start + len > eb->len).
The case is found by switching extent inline ref type from shared data
ref to non-shared data ref, which is a kind of metadata corruption.
It'd use the wrong helper to access the eb,
eg. btrfs_extent_data_ref_root(eb, ref) is used but the %ref passing
here is "struct btrfs_shared_data_ref". And if the extent item
happens to be the first item in the eb, then offset/length will get
over eb->len which ends up an invalid memory access.
This is adding proper checks in order to avoid invalid memory access,
ie. 'general protection fault', before it's too late.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Omit an extra message for a memory allocation failure in this function.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Jan Kara <jack@suse.cz>
Omit an extra message for a memory allocation failure in this function.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Jan Kara <jack@suse.cz>
For a while now any NFSv2 mount where sec= is specified uses
AUTH_NULL. If sec= is not specified, the mount uses AUTH_UNIX.
Commit e68fd7c807 ("mount: use sec= that was specified on the
command line") attempted to address a very similar problem with
NFSv3, and should have fixed this too, but it has a bug.
The MNTv1 MNT procedure does not return a list of security flavors,
so our client makes up a list containing just AUTH_NULL. This should
enable nfs_verify_authflavors() to assign the sec= specified flavor,
but instead, it incorrectly sets it to AUTH_NULL.
I expect this would also be a problem for any NFSv3 server whose
MNTv3 MNT procedure returned a security flavor list containing only
AUTH_NULL.
Fixes: e68fd7c807 ("mount: use sec= that was specified on ... ")
BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=310
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
An NFSv4.1 client might close a file after the user who opened it has
logged off. In this case the user's credentials may no longer be
valid, if they are e.g. kerberos credentials that have expired.
NFSv4.1 has a mechanism to allow the client to use machine credentials
to close a file. However due to a short-coming in the RFC, a CLOSE
with those credentials may not be possible if the file in question
isn't exported to the same security flavor - the required PUTFH must
be rejected when this is the case.
Specifically if a server and client support kerberos in general and
have used it to form a machine credential, but the file is only
exported to "sec=sys", a PUTFH with the machine credentials will fail,
so CLOSE is not possible.
As RPC_AUTH_UNIX (used by sec=sys) credentials can never expire, there
is no value in using the machine credential in place of them.
So in that case, just use the users credentials for CLOSE etc, as you would
in NFSv4.0
Signed-off-by: Neil Brown <neilb@suse.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Pull x86 fixes from Thomas Gleixner:
"Another pile of small fixes and updates for x86:
- Plug a hole in the SMAP implementation which misses to clear AC on
NMI entry
- Fix the norandmaps/ADDR_NO_RANDOMIZE logic so the command line
parameter works correctly again
- Use the proper accessor in the startup64 code for next_early_pgt to
prevent accessing of invalid addresses and faulting in the early
boot code.
- Prevent CPU hotplug lock recursion in the MTRR code
- Unbreak CPU0 hotplugging
- Rename overly long CPUID bits which got introduced in this cycle
- Two commits which mark data 'const' and restrict the scope of data
and functions to file scope by making them 'static'"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Constify attribute_group structures
x86/boot/64/clang: Use fixup_pointer() to access 'next_early_pgt'
x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE checks
x86: Fix norandmaps/ADDR_NO_RANDOMIZE
x86/mtrr: Prevent CPU hotplug lock recursion
x86: Mark various structures and functions as 'static'
x86/cpufeature, kvm/svm: Rename (shorten) the new "virtualized VMSAVE/VMLOAD" CPUID flag
x86/smpboot: Unbreak CPU0 hotplug
x86/asm/64: Clear AC on NMI entries
Now that the mirror allocation has been moved, the parameter can go.
Also remove the redundant symbol export.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
There are a number of callers of nfs_pageio_complete() that want to
continue using the nfs_pageio_descriptor without needing to call
nfs_pageio_init() again. Examples include nfs_pageio_resend() and
nfs_pageio_cond_complete().
The problem is that nfs_pageio_complete() also calls
nfs_pageio_cleanup_mirroring(), which frees up the array of mirrors.
This can lead to writeback errors, in the next call to
nfs_pageio_setup_mirroring().
Fix by simply moving the allocation of the mirrors to
nfs_pageio_setup_mirroring().
Link: https://bugzilla.kernel.org/show_bug.cgi?id=196709
Reported-by: JianhongYin <yin-jianhong@163.com>
Cc: stable@vger.kernel.org # 4.0+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Pull xfs fixes from Darrick Wong:
"A handful more bug fixes for you today.
Changes since last time:
- Don't leak resources when mount fails
- Don't accidentally clobber variables when looking for free inodes"
* tag 'xfs-4.13-fixes-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: don't leak quotacheck dquots when cow recovery
xfs: clear MS_ACTIVE after finishing log recovery
iomap: fix integer truncation issues in the zeroing and dirtying helpers
xfs: fix inobt inode allocation search optimization
The buffer passed to btrfs_ioctl_tree_search* functions have to be at least
sizeof(struct btrfs_ioctl_search_header). If this is not the case then the
ioctl should return -EOVERFLOW and set the uarg->buf_size to the minimum
required size. Currently btrfs_ioctl_tree_search_v2 would return an -EOVERFLOW
error with ->buf_size being set to the value passed by user space. Fix this by
removing the size check and relying on search_ioctl, which already includes it
and correctly sets buf_size.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently the code checks whether we should do data checksumming in
btrfs_submit_direct and the boolean result of this check is passed to
btrfs_submit_direct_hook, in turn passing it to __btrfs_submit_dio_bio which
actually consumes it. The last function actually has all the necessary context
to figure out whether to skip the check or not, so let's move the check closer
to where it's being consumed. No functional changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Chris Mason <clm@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If the range being cleared was not marked for defrag and we are not
about to clear the range from the defrag status, we don't need to
lock and unlock the inode.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Chris Mason <clm@fb.com>
Reviewed-by: Wang Shilong <wangshilong1991@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The error return variable ret is initialized to zero and then is
checked to see if it is non-zero in the if-block that follows it.
It is therefore impossible for ret to be non-zero after the if-block
hence the check is redundant and can be removed.
Detected by CoverityScan, CID#1021040 ("Logically dead code")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The internal free space tree management routines are always exposed for
testing purposes. Make them dependent on SANITY_TESTS being on so that
they are exposed only when they really have to.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This variable was added in 1abe9b8a13 ("Btrfs: add initial tracepointi
support for btrfs"), yet it never really got used, only assigned to. So
let's remove it.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a WARN_ON(!var) inside an if branch which is executed (among
others) only when var is true.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Though BTRFS_FSID_SIZE and BTRFS_UUID_SIZE are of the same size, we
should use the matching constant for the fsid buffer.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Our dir_context->pos is supposed to hold the next position we're
supposed to look. If we successfully insert a delayed dir index we
could end up with a duplicate entry because we don't increase ctx->pos
after doing the dir_emit.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This reverts commit 68c4a4f8ab, with
various conflict clean-ups.
The capability check required too much privilege compared to simple DAC
controls. A system builder was forced to have crash handler processes
run with CAP_SYSLOG which would give it the ability to read (and wipe)
the _current_ dmesg, which is much more access than being given access
only to the historical log stored in pstorefs.
With the prior commit to make the root directory 0750, the files are
protected by default but a system builder can now opt to give access
to a specific group (via chgrp on the pstorefs root directory) without
being forced to also give away CAP_SYSLOG.
Suggested-by: Nick Kralevich <nnk@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Currently only DMESG and CONSOLE record types are protected, and it isn't
obvious that they are using a capability check. Instead switch to explicit
root directory mode of 0750 to keep files private by default. This will
allow the removal of the capability check, which was non-obvious and
forces a process to have possibly too much privilege when simple post-boot
chgrp for readers would be possible without it.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
dq_data_lock is currently used to protect all modifications of quota
accounting information, consistency of quota accounting on the inode,
and dquot pointers from inode. As a result contention on the lock can be
pretty heavy.
Reduce the contention on the lock by protecting quota accounting
information by a new dquot->dq_dqb_lock and consistency of quota
accounting with inode usage by inode->i_lock.
This change reduces time to create 500000 files on ext4 on ramdisk by 50
different processes in separate directories by 6% when user quota is
turned on. When those 50 processes belong to 50 different users, the
improvement is about 9%.
Signed-off-by: Jan Kara <jack@suse.cz>
Provide helper __inode_get_bytes() which assumes i_lock is already
acquired. Quota code will need this to be able to use i_lock to protect
consistency of quota accounting information and inode usage.
Signed-off-by: Jan Kara <jack@suse.cz>
inode_incr_space() and inode_decr_space() have only two callsites.
Inline them there as that will make locking changes simpler.
Signed-off-by: Jan Kara <jack@suse.cz>
