Relocation of a block group waits for all existing tasks flushing
dellaloc, starting direct IO writes and any ordered extents before
starting the relocation process. However for direct IO writes that end
up doing nocow (inode either has the flag nodatacow set or the write is
against a prealloc extent) we have a short time window that allows for a
race that makes relocation proceed without waiting for the direct IO
write to complete first, resulting in data loss after the relocation
finishes. This is illustrated by the following diagram:
CPU 1 CPU 2
btrfs_relocate_block_group(bg X)
direct IO write starts against
an extent in block group X
using nocow mode (inode has the
nodatacow flag or the write is
for a prealloc extent)
btrfs_direct_IO()
btrfs_get_blocks_direct()
--> can_nocow_extent() returns 1
btrfs_inc_block_group_ro(bg X)
--> turns block group into RO mode
btrfs_wait_ordered_roots()
--> returns and does not know about
the DIO write happening at CPU 2
(the task there has not created
yet an ordered extent)
relocate_block_group(bg X)
--> rc->stage == MOVE_DATA_EXTENTS
find_next_extent()
--> returns extent that the DIO
write is going to write to
relocate_data_extent()
relocate_file_extent_cluster()
--> reads the extent from disk into
pages belonging to the relocation
inode and dirties them
--> creates DIO ordered extent
btrfs_submit_direct()
--> submits bio against a location
on disk obtained from an extent
map before the relocation started
btrfs_wait_ordered_range()
--> writes all the pages read before
to disk (belonging to the
relocation inode)
relocation finishes
bio completes and wrote new data
to the old location of the block
group
So fix this by tracking the number of nocow writers for a block group and
make sure relocation waits for that number to go down to 0 before starting
to move the extents.
The same race can also happen with buffered writes in nocow mode since the
patch I recently made titled "Btrfs: don't do unnecessary delalloc flushes
when relocating", because we are no longer flushing all delalloc which
served as a synchonization mechanism (due to page locking) and ensured
the ordered extents for nocow buffered writes were created before we
called btrfs_wait_ordered_roots(). The race with direct IO writes in nocow
mode existed before that patch (no pages are locked or used during direct
IO) and that fixed only races with direct IO writes that do cow.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
When we do a direct IO write against a preallocated extent (fallocate)
that does not go beyond the i_size of the inode, we do the write operation
without holding the inode's i_mutex (an optimization that landed in
commit 38851cc19a ("Btrfs: implement unlocked dio write")). This allows
for a very tiny time window where a race can happen with a concurrent
fsync using the fast code path, as the direct IO write path creates first
a new extent map (no longer flagged as a prealloc extent) and then it
creates the ordered extent, while the fast fsync path first collects
ordered extents and then it collects extent maps. This allows for the
possibility of the fast fsync path to collect the new extent map without
collecting the new ordered extent, and therefore logging an extent item
based on the extent map without waiting for the ordered extent to be
created and complete. This can result in a situation where after a log
replay we end up with an extent not marked anymore as prealloc but it was
only partially written (or not written at all), exposing random, stale or
garbage data corresponding to the unwritten pages and without any
checksums in the csum tree covering the extent's range.
This is an extension of what was done in commit de0ee0edb2 ("Btrfs: fix
race between fsync and lockless direct IO writes").
So fix this by creating first the ordered extent and then the extent
map, so that this way if the fast fsync patch collects the new extent
map it also collects the corresponding ordered extent.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
When we do a rename with the whiteout flag, we need to create the whiteout
inode, which in the worst case requires 5 transaction units (1 inode item,
1 inode ref, 2 dir items and 1 xattr if selinux is enabled). So bump the
number of transaction units from 11 to 16 if the whiteout flag is set.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
The btrfs_rename_exchange() started as a copy-paste from btrfs_rename(),
which had a race fixed by my previous patch titled "Btrfs: pin log earlier
when renaming", and so it suffers from the same problem.
We pin the logs of the affected roots after we insert the new inode
references, leaving a time window where concurrent tasks logging the
inodes can end up logging both the new and old references, resulting
in log trees that when replayed can turn the metadata into inconsistent
states. This behaviour was added to btrfs_rename() in 2009 without any
explanation about why not pinning the logs earlier, just leaving a
comment about the posibility for the race. As of today it's perfectly
safe and sane to pin the logs before we start doing any of the steps
involved in the rename operation.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
If rename exchange operations fail at some point after we pinned any of
the logs, we end up aborting the current transaction but never unpin the
logs, which leaves concurrent tasks that are trying to sync the logs (as
part of an fsync request from user space) blocked forever and preventing
the filesystem from being unmountable.
Fix this by safely unpinning the log.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
If we failed to fully setup the whiteout inode during a rename operation
with the whiteout flag, we ended up leaking the inode, not decrementing
its link count nor removing all its items from the fs/subvol tree.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Two new flags, RENAME_EXCHANGE and RENAME_WHITEOUT, provide for new
behavior in the renameat2() syscall. This behavior is primarily used by
overlayfs. This patch adds support for these flags to btrfs, enabling it to
be used as a fully functional upper layer for overlayfs.
RENAME_EXCHANGE support was written by Davide Italiano originally
submitted on 2 April 2015.
Signed-off-by: Davide Italiano <dccitaliano@gmail.com>
Signed-off-by: Dan Fuhry <dfuhry@datto.com>
[ remove unlikely ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
We were pinning the log right after the first step in the rename operation
(inserting inode ref for the new name in the destination directory)
instead of doing it before. This behaviour was introduced in 2009 for some
reason that was not mentioned neither on the changelog nor any comment,
with the drawback of a small time window where concurrent log writers can
end up logging the new inode reference for the inode we are renaming while
the rename operation is in progress (so that we can end up with a log
containing both the new and old references). As of today there's no reason
to not pin the log before that first step anymore, so just fix this.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
If rename operations fail at some point after we pinned the log, we end
up aborting the current transaction but never unpin the log, which leaves
concurrent tasks that are trying to sync the log (as part of an fsync
request from user space) blocked forever and preventing the filesystem
from being unmountable.
Fix this by safely unpinning the log.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Before we start the actual relocation process of a block group, we do
calls to flush delalloc of all inodes and then wait for ordered extents
to complete. However we do these flush calls just to make sure we don't
race with concurrent tasks that have actually already started to run
delalloc and have allocated an extent from the block group we want to
relocate, right before we set it to readonly mode, but have not yet
created the respective ordered extents. The flush calls make us wait
for such concurrent tasks because they end up calling
filemap_fdatawrite_range() (through btrfs_start_delalloc_roots() ->
__start_delalloc_inodes() -> btrfs_alloc_delalloc_work() ->
btrfs_run_delalloc_work()) which ends up serializing us with those tasks
due to attempts to lock the same pages (and the delalloc flush procedure
calls the allocator and creates the ordered extents before unlocking the
pages).
These flushing calls not only make us waste time (cpu, IO) but also reduce
the chances of writing larger extents (applications might be writing to
contiguous ranges and we flush before they finish dirtying the whole
ranges).
So make sure we don't flush delalloc and just wait for concurrent tasks
that have already started flushing delalloc and have allocated an extent
from the block group we are about to relocate.
This change also ends up fixing a race with direct IO writes that makes
relocation not wait for direct IO ordered extents. This race is
illustrated by the following diagram:
CPU 1 CPU 2
btrfs_relocate_block_group(bg X)
starts direct IO write,
target inode currently has no
ordered extents ongoing nor
dirty pages (delalloc regions),
therefore the root for our inode
is not in the list
fs_info->ordered_roots
btrfs_direct_IO()
__blockdev_direct_IO()
btrfs_get_blocks_direct()
btrfs_lock_extent_direct()
locks range in the io tree
btrfs_new_extent_direct()
btrfs_reserve_extent()
--> extent allocated
from bg X
btrfs_inc_block_group_ro(bg X)
btrfs_start_delalloc_roots()
__start_delalloc_inodes()
--> does nothing, no dealloc ranges
in the inode's io tree so the
inode's root is not in the list
fs_info->delalloc_roots
btrfs_wait_ordered_roots()
--> does not find the inode's root in the
list fs_info->ordered_roots
--> ends up not waiting for the direct IO
write started by the task at CPU 2
relocate_block_group(rc->stage ==
MOVE_DATA_EXTENTS)
prepare_to_relocate()
btrfs_commit_transaction()
iterates the extent tree, using its
commit root and moves extents into new
locations
btrfs_add_ordered_extent_dio()
--> now a ordered extent is
created and added to the
list root->ordered_extents
and the root added to the
list fs_info->ordered_roots
--> this is too late and the
task at CPU 1 already
started the relocation
btrfs_commit_transaction()
btrfs_finish_ordered_io()
btrfs_alloc_reserved_file_extent()
--> adds delayed data reference
for the extent allocated
from bg X
relocate_block_group(rc->stage ==
UPDATE_DATA_PTRS)
prepare_to_relocate()
btrfs_commit_transaction()
--> delayed refs are run, so an extent
item for the allocated extent from
bg X is added to extent tree
--> commit roots are switched, so the
next scan in the extent tree will
see the extent item
sees the extent in the extent tree
When this happens the relocation produces the following warning when it
finishes:
[ 7260.832836] ------------[ cut here ]------------
[ 7260.834653] WARNING: CPU: 5 PID: 6765 at fs/btrfs/relocation.c:4318 btrfs_relocate_block_group+0x245/0x2a1 [btrfs]()
[ 7260.838268] Modules linked in: btrfs crc32c_generic xor ppdev raid6_pq psmouse sg acpi_cpufreq evdev i2c_piix4 tpm_tis serio_raw tpm i2c_core pcspkr parport_pc
[ 7260.850935] CPU: 5 PID: 6765 Comm: btrfs Not tainted 4.5.0-rc6-btrfs-next-28+ #1
[ 7260.852998] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[ 7260.852998] 0000000000000000 ffff88020bf57bc0 ffffffff812648b3 0000000000000000
[ 7260.852998] 0000000000000009 ffff88020bf57bf8 ffffffff81051608 ffffffffa03c1b2d
[ 7260.852998] ffff8800b2bbb800 0000000000000000 ffff8800b17bcc58 ffff8800399dd000
[ 7260.852998] Call Trace:
[ 7260.852998] [<ffffffff812648b3>] dump_stack+0x67/0x90
[ 7260.852998] [<ffffffff81051608>] warn_slowpath_common+0x99/0xb2
[ 7260.852998] [<ffffffffa03c1b2d>] ? btrfs_relocate_block_group+0x245/0x2a1 [btrfs]
[ 7260.852998] [<ffffffff810516d4>] warn_slowpath_null+0x1a/0x1c
[ 7260.852998] [<ffffffffa03c1b2d>] btrfs_relocate_block_group+0x245/0x2a1 [btrfs]
[ 7260.852998] [<ffffffffa039d9de>] btrfs_relocate_chunk.isra.29+0x66/0xdb [btrfs]
[ 7260.852998] [<ffffffffa039f314>] btrfs_balance+0xde1/0xe4e [btrfs]
[ 7260.852998] [<ffffffff8127d671>] ? debug_smp_processor_id+0x17/0x19
[ 7260.852998] [<ffffffffa03a9583>] btrfs_ioctl_balance+0x255/0x2d3 [btrfs]
[ 7260.852998] [<ffffffffa03ac96a>] btrfs_ioctl+0x11e0/0x1dff [btrfs]
[ 7260.852998] [<ffffffff811451df>] ? handle_mm_fault+0x443/0xd63
[ 7260.852998] [<ffffffff81491817>] ? _raw_spin_unlock+0x31/0x44
[ 7260.852998] [<ffffffff8108b36a>] ? arch_local_irq_save+0x9/0xc
[ 7260.852998] [<ffffffff811876ab>] vfs_ioctl+0x18/0x34
[ 7260.852998] [<ffffffff81187cb2>] do_vfs_ioctl+0x550/0x5be
[ 7260.852998] [<ffffffff81190c30>] ? __fget_light+0x4d/0x71
[ 7260.852998] [<ffffffff81187d77>] SyS_ioctl+0x57/0x79
[ 7260.852998] [<ffffffff81492017>] entry_SYSCALL_64_fastpath+0x12/0x6b
[ 7260.893268] ---[ end trace eb7803b24ebab8ad ]---
This is because at the end of the first stage, in relocate_block_group(),
we commit the current transaction, which makes delayed refs run, the
commit roots are switched and so the second stage will find the extent
item that the ordered extent added to the delayed refs. But this extent
was not moved (ordered extent completed after first stage finished), so
at the end of the relocation our block group item still has a positive
used bytes counter, triggering a warning at the end of
btrfs_relocate_block_group(). Later on when trying to read the extent
contents from disk we hit a BUG_ON() due to the inability to map a block
with a logical address that belongs to the block group we relocated and
is no longer valid, resulting in the following trace:
[ 7344.885290] BTRFS critical (device sdi): unable to find logical 12845056 len 4096
[ 7344.887518] ------------[ cut here ]------------
[ 7344.888431] kernel BUG at fs/btrfs/inode.c:1833!
[ 7344.888431] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[ 7344.888431] Modules linked in: btrfs crc32c_generic xor ppdev raid6_pq psmouse sg acpi_cpufreq evdev i2c_piix4 tpm_tis serio_raw tpm i2c_core pcspkr parport_pc
[ 7344.888431] CPU: 0 PID: 6831 Comm: od Tainted: G W 4.5.0-rc6-btrfs-next-28+ #1
[ 7344.888431] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[ 7344.888431] task: ffff880215818600 ti: ffff880204684000 task.ti: ffff880204684000
[ 7344.888431] RIP: 0010:[<ffffffffa037c88c>] [<ffffffffa037c88c>] btrfs_merge_bio_hook+0x54/0x6b [btrfs]
[ 7344.888431] RSP: 0018:ffff8802046878f0 EFLAGS: 00010282
[ 7344.888431] RAX: 00000000ffffffea RBX: 0000000000001000 RCX: 0000000000000001
[ 7344.888431] RDX: ffff88023ec0f950 RSI: ffffffff8183b638 RDI: 00000000ffffffff
[ 7344.888431] RBP: ffff880204687908 R08: 0000000000000001 R09: 0000000000000000
[ 7344.888431] R10: ffff880204687770 R11: ffffffff82f2d52d R12: 0000000000001000
[ 7344.888431] R13: ffff88021afbfee8 R14: 0000000000006208 R15: ffff88006cd199b0
[ 7344.888431] FS: 00007f1f9e1d6700(0000) GS:ffff88023ec00000(0000) knlGS:0000000000000000
[ 7344.888431] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 7344.888431] CR2: 00007f1f9dc8cb60 CR3: 000000023e3b6000 CR4: 00000000000006f0
[ 7344.888431] Stack:
[ 7344.888431] 0000000000001000 0000000000001000 ffff880204687b98 ffff880204687950
[ 7344.888431] ffffffffa0395c8f ffffea0004d64d48 0000000000000000 0000000000001000
[ 7344.888431] ffffea0004d64d48 0000000000001000 0000000000000000 0000000000000000
[ 7344.888431] Call Trace:
[ 7344.888431] [<ffffffffa0395c8f>] submit_extent_page+0xf5/0x16f [btrfs]
[ 7344.888431] [<ffffffffa03970ac>] __do_readpage+0x4a0/0x4f1 [btrfs]
[ 7344.888431] [<ffffffffa039680d>] ? btrfs_create_repair_bio+0xcb/0xcb [btrfs]
[ 7344.888431] [<ffffffffa037eeb4>] ? btrfs_writepage_start_hook+0xbc/0xbc [btrfs]
[ 7344.888431] [<ffffffff8108df55>] ? trace_hardirqs_on+0xd/0xf
[ 7344.888431] [<ffffffffa039728c>] __do_contiguous_readpages.constprop.26+0xc2/0xe4 [btrfs]
[ 7344.888431] [<ffffffffa037eeb4>] ? btrfs_writepage_start_hook+0xbc/0xbc [btrfs]
[ 7344.888431] [<ffffffffa039739b>] __extent_readpages.constprop.25+0xed/0x100 [btrfs]
[ 7344.888431] [<ffffffff81129d24>] ? lru_cache_add+0xe/0x10
[ 7344.888431] [<ffffffffa0397ea8>] extent_readpages+0x160/0x1aa [btrfs]
[ 7344.888431] [<ffffffffa037eeb4>] ? btrfs_writepage_start_hook+0xbc/0xbc [btrfs]
[ 7344.888431] [<ffffffff8115daad>] ? alloc_pages_current+0xa9/0xcd
[ 7344.888431] [<ffffffffa037cdc9>] btrfs_readpages+0x1f/0x21 [btrfs]
[ 7344.888431] [<ffffffff81128316>] __do_page_cache_readahead+0x168/0x1fc
[ 7344.888431] [<ffffffff811285a0>] ondemand_readahead+0x1f6/0x207
[ 7344.888431] [<ffffffff811285a0>] ? ondemand_readahead+0x1f6/0x207
[ 7344.888431] [<ffffffff8111cf34>] ? pagecache_get_page+0x2b/0x154
[ 7344.888431] [<ffffffff8112870e>] page_cache_sync_readahead+0x3d/0x3f
[ 7344.888431] [<ffffffff8111dbf7>] generic_file_read_iter+0x197/0x4e1
[ 7344.888431] [<ffffffff8117773a>] __vfs_read+0x79/0x9d
[ 7344.888431] [<ffffffff81178050>] vfs_read+0x8f/0xd2
[ 7344.888431] [<ffffffff81178a38>] SyS_read+0x50/0x7e
[ 7344.888431] [<ffffffff81492017>] entry_SYSCALL_64_fastpath+0x12/0x6b
[ 7344.888431] Code: 8d 4d e8 45 31 c9 45 31 c0 48 8b 00 48 c1 e2 09 48 8b 80 80 fc ff ff 4c 89 65 e8 48 8b b8 f0 01 00 00 e8 1d 42 02 00 85 c0 79 02 <0f> 0b 4c 0
[ 7344.888431] RIP [<ffffffffa037c88c>] btrfs_merge_bio_hook+0x54/0x6b [btrfs]
[ 7344.888431] RSP <ffff8802046878f0>
[ 7344.970544] ---[ end trace eb7803b24ebab8ae ]---
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Before the relocation process of a block group starts, it sets the block
group to readonly mode, then flushes all delalloc writes and then finally
it waits for all ordered extents to complete. This last step includes
waiting for ordered extents destinated at extents allocated in other block
groups, making us waste unecessary time.
So improve this by waiting only for ordered extents that fall into the
block group's range.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
If we create a symlink, fsync its parent directory, crash/power fail and
mount the filesystem, we end up with an empty symlink, which not only is
useless it's also not allowed in linux (the man page symlink(2) is well
explicit about that). So we just need to make sure to fully log an inode
if it's a symlink, to ensure its inline extent gets logged, ensuring the
same behaviour as ext3, ext4, xfs, reiserfs, f2fs, nilfs2, etc.
Example reproducer:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ mkdir /mnt/testdir
$ sync
$ ln -s /mnt/foo /mnt/testdir/bar
$ xfs_io -c fsync /mnt/testdir
<power fail>
$ mount /dev/sdb /mnt
$ readlink /mnt/testdir/bar
<empty string>
A test case for fstests follows soon.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
If we move a directory to a new parent and later log that parent and don't
explicitly log the old parent, when we replay the log we can end up with
entries for the moved directory in both the old and new parent directories.
Besides being ilegal to have directories with multiple hard links in linux,
it also resulted in the leaving the inode item with a link count of 1.
A similar issue also happens if we move a regular file - after the log tree
is replayed the file has a link in both the old and new parent directories,
when it should be only at the new directory.
Sample reproducer:
$ mkfs.btrfs -f /dev/sdc
$ mount /dev/sdc /mnt
$ mkdir /mnt/x
$ mkdir /mnt/y
$ touch /mnt/x/foo
$ mkdir /mnt/y/z
$ sync
$ ln /mnt/x/foo /mnt/x/bar
$ mv /mnt/y/z /mnt/x/z
< power fail >
$ mount /dev/sdc /mnt
$ ls -1Ri /mnt
/mnt:
257 x
258 y
/mnt/x:
259 bar
259 foo
260 z
/mnt/x/z:
/mnt/y:
260 z
/mnt/y/z:
$ umount /dev/sdc
$ btrfs check /dev/sdc
Checking filesystem on /dev/sdc
UUID: a67e2c4a-a4b4-4fdc-b015-9d9af1e344be
checking extents
checking free space cache
checking fs roots
root 5 inode 260 errors 2000, link count wrong
unresolved ref dir 257 index 4 namelen 1 name z filetype 2 errors 0
unresolved ref dir 258 index 2 namelen 1 name z filetype 2 errors 0
(...)
Attempting to remove the directory becomes impossible:
$ mount /dev/sdc /mnt
$ rmdir /mnt/y/z
$ ls -lh /mnt/y
ls: cannot access /mnt/y/z: No such file or directory
total 0
d????????? ? ? ? ? ? z
$ rmdir /mnt/x/z
rmdir: failed to remove ‘/mnt/x/z’: Stale file handle
$ ls -lh /mnt/x
ls: cannot access /mnt/x/z: Stale file handle
total 0
-rw-r--r-- 2 root root 0 Apr 6 18:06 bar
-rw-r--r-- 2 root root 0 Apr 6 18:06 foo
d????????? ? ? ? ? ? z
So make sure that on rename we set the last_unlink_trans value for our
inode, even if it's a directory, to the value of the current transaction's
ID and that if the new parent directory is logged that we fallback to a
transaction commit.
A test case for fstests is being submitted as well.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
If /proc/<PID>/environ gets read before the envp[] array is fully set up
in create_{aout,elf,elf_fdpic,flat}_tables(), we might end up trying to
read more bytes than are actually written, as env_start will already be
set but env_end will still be zero, making the range calculation
underflow, allowing to read beyond the end of what has been written.
Fix this as it is done for /proc/<PID>/cmdline by testing env_end for
zero. It is, apparently, intentionally set last in create_*_tables().
This bug was found by the PaX size_overflow plugin that detected the
arithmetic underflow of 'this_len = env_end - (env_start + src)' when
env_end is still zero.
The expected consequence is that userland trying to access
/proc/<PID>/environ of a not yet fully set up process may get
inconsistent data as we're in the middle of copying in the environment
variables.
Fixes: https://forums.grsecurity.net/viewtopic.php?f=3&t=4363
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=116461
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Emese Revfy <re.emese@gmail.com>
Cc: Pax Team <pageexec@freemail.hu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull userns fix from Eric Biederman:
"This contains just a single fix for a nasty oops"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
propogate_mnt: Handle the first propogated copy being a slave
When the first propgated copy was a slave the following oops would result:
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
> IP: [<ffffffff811fba4e>] propagate_one+0xbe/0x1c0
> PGD bacd4067 PUD bac66067 PMD 0
> Oops: 0000 [#1] SMP
> Modules linked in:
> CPU: 1 PID: 824 Comm: mount Not tainted 4.6.0-rc5userns+ #1523
> Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
> task: ffff8800bb0a8000 ti: ffff8800bac3c000 task.ti: ffff8800bac3c000
> RIP: 0010:[<ffffffff811fba4e>] [<ffffffff811fba4e>] propagate_one+0xbe/0x1c0
> RSP: 0018:ffff8800bac3fd38 EFLAGS: 00010283
> RAX: 0000000000000000 RBX: ffff8800bb77ec00 RCX: 0000000000000010
> RDX: 0000000000000000 RSI: ffff8800bb58c000 RDI: ffff8800bb58c480
> RBP: ffff8800bac3fd48 R08: 0000000000000001 R09: 0000000000000000
> R10: 0000000000001ca1 R11: 0000000000001c9d R12: 0000000000000000
> R13: ffff8800ba713800 R14: ffff8800bac3fda0 R15: ffff8800bb77ec00
> FS: 00007f3c0cd9b7e0(0000) GS:ffff8800bfb00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000010 CR3: 00000000bb79d000 CR4: 00000000000006e0
> Stack:
> ffff8800bb77ec00 0000000000000000 ffff8800bac3fd88 ffffffff811fbf85
> ffff8800bac3fd98 ffff8800bb77f080 ffff8800ba713800 ffff8800bb262b40
> 0000000000000000 0000000000000000 ffff8800bac3fdd8 ffffffff811f1da0
> Call Trace:
> [<ffffffff811fbf85>] propagate_mnt+0x105/0x140
> [<ffffffff811f1da0>] attach_recursive_mnt+0x120/0x1e0
> [<ffffffff811f1ec3>] graft_tree+0x63/0x70
> [<ffffffff811f1f6b>] do_add_mount+0x9b/0x100
> [<ffffffff811f2c1a>] do_mount+0x2aa/0xdf0
> [<ffffffff8117efbe>] ? strndup_user+0x4e/0x70
> [<ffffffff811f3a45>] SyS_mount+0x75/0xc0
> [<ffffffff8100242b>] do_syscall_64+0x4b/0xa0
> [<ffffffff81988f3c>] entry_SYSCALL64_slow_path+0x25/0x25
> Code: 00 00 75 ec 48 89 0d 02 22 22 01 8b 89 10 01 00 00 48 89 05 fd 21 22 01 39 8e 10 01 00 00 0f 84 e0 00 00 00 48 8b 80 d8 00 00 00 <48> 8b 50 10 48 89 05 df 21 22 01 48 89 15 d0 21 22 01 8b 53 30
> RIP [<ffffffff811fba4e>] propagate_one+0xbe/0x1c0
> RSP <ffff8800bac3fd38>
> CR2: 0000000000000010
> ---[ end trace 2725ecd95164f217 ]---
This oops happens with the namespace_sem held and can be triggered by
non-root users. An all around not pleasant experience.
To avoid this scenario when finding the appropriate source mount to
copy stop the walk up the mnt_master chain when the first source mount
is encountered.
Further rewrite the walk up the last_source mnt_master chain so that
it is clear what is going on.
The reason why the first source mount is special is that it it's
mnt_parent is not a mount in the dest_mnt propagation tree, and as
such termination conditions based up on the dest_mnt mount propgation
tree do not make sense.
To avoid other kinds of confusion last_dest is not changed when
computing last_source. last_dest is only used once in propagate_one
and that is above the point of the code being modified, so changing
the global variable is meaningless and confusing.
Cc: stable@vger.kernel.org
fixes: f2ebb3a921 ("smarter propagate_mnt()")
Reported-by: Tycho Andersen <tycho.andersen@canonical.com>
Reviewed-by: Seth Forshee <seth.forshee@canonical.com>
Tested-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull fuse fixes from Miklos Szeredi:
"Fix a regression and update the MAINTAINERS entry for fuse"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: update mailing list in MAINTAINERS
fuse: Fix return value from fuse_get_user_pages()
Pull UDF fix from Jan Kara:
"A fix of a regression in UDF that got introduced in 4.6-rc1 by one of
the charset encoding fixes"
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
udf: Fix conversion of 'dstring' fields to UTF8
Merge fixes from Andrew Morton:
"20 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
Documentation/sysctl/vm.txt: update numa_zonelist_order description
lib/stackdepot.c: allow the stack trace hash to be zero
rapidio: fix potential NULL pointer dereference
mm/memory-failure: fix race with compound page split/merge
ocfs2/dlm: return zero if deref_done message is successfully handled
Ananth has moved
kcov: don't profile branches in kcov
kcov: don't trace the code coverage code
mm: wake kcompactd before kswapd's short sleep
.mailmap: add Frank Rowand
mm/hwpoison: fix wrong num_poisoned_pages accounting
mm: call swap_slot_free_notify() with page lock held
mm: vmscan: reclaim highmem zone if buffer_heads is over limit
numa: fix /proc/<pid>/numa_maps for THP
mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check
mailmap: fix Krzysztof Kozlowski's misspelled name
thp: keep huge zero page pinned until tlb flush
mm: exclude HugeTLB pages from THP page_mapped() logic
kexec: export OFFSET(page.compound_head) to find out compound tail page
kexec: update VMCOREINFO for compound_order/dtor
dlm_deref_lockres_done_handler() should return zero if the message is
successfully handled.
Fixes: 60d663cb52 ("ocfs2/dlm: add DEREF_DONE message").
Signed-off-by: xuejiufei <xuejiufei@huawei.com>
Reviewed-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In gather_pte_stats() a THP pmd is cast into a pte, which is wrong
because the layouts may differ depending on the architecture. On s390
this will lead to inaccurate numa_maps accounting in /proc because of
misguided pte_present() and pte_dirty() checks on the fake pte.
On other architectures pte_present() and pte_dirty() may work by chance,
but there may be an issue with direct-access (dax) mappings w/o
underlying struct pages when HAVE_PTE_SPECIAL is set and THP is
available. In vm_normal_page() the fake pte will be checked with
pte_special() and because there is no "special" bit in a pmd, this will
always return false and the VM_PFNMAP | VM_MIXEDMAP checking will be
skipped. On dax mappings w/o struct pages, an invalid struct page
pointer would then be returned that can crash the kernel.
This patch fixes the numa_maps THP handling by introducing new "_pmd"
variants of the can_gather_numa_stats() and vm_normal_page() functions.
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org> [4.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull Ceph fixes from Sage Weil:
"There is a lifecycle fix in the auth code, a fix for a narrow race
condition on map, and a helpful message in the log when there is a
feature mismatch (which happens frequently now that the default
server-side options have changed)"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
rbd: report unsupported features to syslog
rbd: fix rbd map vs notify races
libceph: make authorizer destruction independent of ceph_auth_client
This is more prep-work for the upcoming pty changes. Still just code
cleanup with no actual semantic changes.
This removes a bunch pointless complexity by just having the slave pty
side remember the dentry associated with the devpts slave rather than
the inode. That allows us to remove all the "look up the dentry" code
for when we want to remove it again.
Together with moving the tty pointer from "inode->i_private" to
"dentry->d_fsdata" and getting rid of pointless inode locking, this
removes about 30 lines of code. Not only is the end result smaller,
it's simpler and easier to understand.
The old code, for example, depended on the d_find_alias() to not just
find the dentry, but also to check that it is still hashed, which in
turn validated the tty pointer in the inode.
That is a _very_ roundabout way to say "invalidate the cached tty
pointer when the dentry is removed".
The new code just does
dentry->d_fsdata = NULL;
in devpts_pty_kill() instead, invalidating the tty pointer rather more
directly and obviously. Don't do something complex and subtle when the
obvious straightforward approach will do.
The rest of the patch (ie apart from code deletion and the above tty
pointer clearing) is just switching the calling convention to pass the
dentry or file pointer around instead of the inode.
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Serge Hallyn <serge.hallyn@ubuntu.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc: Jann Horn <jann@thejh.net>
Cc: Greg KH <greg@kroah.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Florian Weimer <fw@deneb.enyo.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Starting the kernel client with cephx disabled and then enabling cephx
and restarting userspace daemons can result in a crash:
[262671.478162] BUG: unable to handle kernel paging request at ffffebe000000000
[262671.531460] IP: [<ffffffff811cd04a>] kfree+0x5a/0x130
[262671.584334] PGD 0
[262671.635847] Oops: 0000 [#1] SMP
[262672.055841] CPU: 22 PID: 2961272 Comm: kworker/22:2 Not tainted 4.2.0-34-generic #39~14.04.1-Ubuntu
[262672.162338] Hardware name: Dell Inc. PowerEdge R720/068CDY, BIOS 2.4.3 07/09/2014
[262672.268937] Workqueue: ceph-msgr con_work [libceph]
[262672.322290] task: ffff88081c2d0dc0 ti: ffff880149ae8000 task.ti: ffff880149ae8000
[262672.428330] RIP: 0010:[<ffffffff811cd04a>] [<ffffffff811cd04a>] kfree+0x5a/0x130
[262672.535880] RSP: 0018:ffff880149aeba58 EFLAGS: 00010286
[262672.589486] RAX: 000001e000000000 RBX: 0000000000000012 RCX: ffff8807e7461018
[262672.695980] RDX: 000077ff80000000 RSI: ffff88081af2be04 RDI: 0000000000000012
[262672.803668] RBP: ffff880149aeba78 R08: 0000000000000000 R09: 0000000000000000
[262672.912299] R10: ffffebe000000000 R11: ffff880819a60e78 R12: ffff8800aec8df40
[262673.021769] R13: ffffffffc035f70f R14: ffff8807e5b138e0 R15: ffff880da9785840
[262673.131722] FS: 0000000000000000(0000) GS:ffff88081fac0000(0000) knlGS:0000000000000000
[262673.245377] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[262673.303281] CR2: ffffebe000000000 CR3: 0000000001c0d000 CR4: 00000000001406e0
[262673.417556] Stack:
[262673.472943] ffff880149aeba88 ffff88081af2be04 ffff8800aec8df40 ffff88081af2be04
[262673.583767] ffff880149aeba98 ffffffffc035f70f ffff880149aebac8 ffff8800aec8df00
[262673.694546] ffff880149aebac8 ffffffffc035c89e ffff8807e5b138e0 ffff8805b047f800
[262673.805230] Call Trace:
[262673.859116] [<ffffffffc035f70f>] ceph_x_destroy_authorizer+0x1f/0x50 [libceph]
[262673.968705] [<ffffffffc035c89e>] ceph_auth_destroy_authorizer+0x3e/0x60 [libceph]
[262674.078852] [<ffffffffc0352805>] put_osd+0x45/0x80 [libceph]
[262674.134249] [<ffffffffc035290e>] remove_osd+0xae/0x140 [libceph]
[262674.189124] [<ffffffffc0352aa3>] __reset_osd+0x103/0x150 [libceph]
[262674.243749] [<ffffffffc0354703>] kick_requests+0x223/0x460 [libceph]
[262674.297485] [<ffffffffc03559e2>] ceph_osdc_handle_map+0x282/0x5e0 [libceph]
[262674.350813] [<ffffffffc035022e>] dispatch+0x4e/0x720 [libceph]
[262674.403312] [<ffffffffc034bd91>] try_read+0x3d1/0x1090 [libceph]
[262674.454712] [<ffffffff810ab7c2>] ? dequeue_entity+0x152/0x690
[262674.505096] [<ffffffffc034cb1b>] con_work+0xcb/0x1300 [libceph]
[262674.555104] [<ffffffff8108fb3e>] process_one_work+0x14e/0x3d0
[262674.604072] [<ffffffff810901ea>] worker_thread+0x11a/0x470
[262674.652187] [<ffffffff810900d0>] ? rescuer_thread+0x310/0x310
[262674.699022] [<ffffffff810957a2>] kthread+0xd2/0xf0
[262674.744494] [<ffffffff810956d0>] ? kthread_create_on_node+0x1c0/0x1c0
[262674.789543] [<ffffffff817bd81f>] ret_from_fork+0x3f/0x70
[262674.834094] [<ffffffff810956d0>] ? kthread_create_on_node+0x1c0/0x1c0
What happens is the following:
(1) new MON session is established
(2) old "none" ac is destroyed
(3) new "cephx" ac is constructed
...
(4) old OSD session (w/ "none" authorizer) is put
ceph_auth_destroy_authorizer(ac, osd->o_auth.authorizer)
osd->o_auth.authorizer in the "none" case is just a bare pointer into
ac, which contains a single static copy for all services. By the time
we get to (4), "none" ac, freed in (2), is long gone. On top of that,
a new vtable installed in (3) points us at ceph_x_destroy_authorizer(),
so we end up trying to destroy a "none" authorizer with a "cephx"
destructor operating on invalid memory!
To fix this, decouple authorizer destruction from ac and do away with
a single static "none" authorizer by making a copy for each OSD or MDS
session. Authorizers themselves are independent of ac and so there is
no reason for destroy_authorizer() to be an ac op. Make it an op on
the authorizer itself by turning ceph_authorizer into a real struct.
Fixes: http://tracker.ceph.com/issues/15447
Reported-by: Alan Zhang <alan.zhang@linux.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Sage Weil <sage@redhat.com>
Commit 9293fcfbc1
("udf: Remove struct ustr as non-needed intermediate storage"),
while getting rid of 'struct ustr', does not take any special care
of 'dstring' fields and effectively use fixed field length instead
of actual string length, encoded in the last byte of the field.
Also, commit 484a10f493
("udf: Merge linux specific translation into CS0 conversion function")
introduced checking of the length of the string being converted,
requiring proper alignment to number of bytes constituing each
character.
The UDF volume identifier is represented as a 32-bytes 'dstring',
and needs to be converted from CS0 to UTF8, while mounting UDF
filesystem. The changes in mentioned commits can in some cases
lead to incorrect handling of volume identifier:
- if the actual string in 'dstring' is of maximal length and
does not have zero bytes separating it from dstring encoded
length in last byte, that last byte may be included in conversion,
thus making incorrect resulting string;
- if the identifier is encoded with 2-bytes characters (compression
code is 16), the length of 31 bytes (32 bytes of field length minus
1 byte of compression code), taken as the string length, is reported
as an incorrect (unaligned) length, and the conversion fails, which
in its turn leads to volume mounting failure.
This patch introduces handling of 'dstring' encoded length field
in udf_CS0toUTF8 function, that is used in all and only cases
when 'dstring' fields are converted. Currently these cases are
processing of Volume Identifier and Volume Set Identifier fields.
The function is also renamed to udf_dstrCS0toUTF8 to distinctly
indicate that it handles 'dstring' input.
Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>
Signed-off-by: Jan Kara <jack@suse.cz>
fuse_get_user_pages() should return error or 0. Otherwise fuse_direct_io
read will not return 0 to indicate that read has completed.
Fixes: 742f992708 ("fuse: return patrial success from fuse_direct_io()")
Signed-off-by: Ashish Samant <ashish.samant@oracle.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Merge the ptmx internal interface cleanup branch.
This doesn't change semantics, but it should be a sane basis for
eventually getting the multi-instance devpts code into some sane shape
where we can get rid of the kernel config option. Which we can
hopefully get done next merge window..
* ptmx-cleanup:
devpts: clean up interface to pty drivers
This gets rid of the horrible notion of having that
struct inode *ptmx_inode
be the linchpin of the interface between the pty code and devpts.
By de-emphasizing the ptmx inode, a lot of things actually get cleaner,
and we will have a much saner way forward. In particular, this will
allow us to associate with any particular devpts instance at open-time,
and not be artificially tied to one particular ptmx inode.
The patch itself is actually fairly straightforward, and apart from some
locking and return path cleanups it's pretty mechanical:
- the interfaces that devpts exposes all take "struct pts_fs_info *"
instead of "struct inode *ptmx_inode" now.
NOTE! The "struct pts_fs_info" thing is a completely opaque structure
as far as the pty driver is concerned: it's still declared entirely
internally to devpts. So the pty code can't actually access it in any
way, just pass it as a "cookie" to the devpts code.
- the "look up the pts fs info" is now a single clear operation, that
also does the reference count increment on the pts superblock.
So "devpts_add/del_ref()" is gone, and replaced by a "lookup and get
ref" operation (devpts_get_ref(inode)), along with a "put ref" op
(devpts_put_ref()).
- the pty master "tty->driver_data" field now contains the pts_fs_info,
not the ptmx inode.
- because we don't care about the ptmx inode any more as some kind of
base index, the ref counting can now drop the inode games - it just
gets the ref on the superblock.
- the pts_fs_info now has a back-pointer to the super_block. That's so
that we can easily look up the information we actually need. Although
quite often, the pts fs info was actually all we wanted, and not having
to look it up based on some magical inode makes things more
straightforward.
In particular, now that "devpts_get_ref(inode)" operation should really
be the *only* place we need to look up what devpts instance we're
associated with, and we do it exactly once, at ptmx_open() time.
The other side of this is that one ptmx node could now be associated
with multiple different devpts instances - you could have a single
/dev/ptmx node, and then have multiple mount namespaces with their own
instances of devpts mounted on /dev/pts/. And that's all perfectly sane
in a model where we just look up the pts instance at open time.
This will eventually allow us to get rid of our odd single-vs-multiple
pts instance model, but this patch in itself changes no semantics, only
an internal binding model.
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Serge Hallyn <serge.hallyn@ubuntu.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc: Jann Horn <jann@thejh.net>
Cc: Greg KH <greg@kroah.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Florian Weimer <fw@deneb.enyo.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Here are 3 small fixes 4.6-rc4. Two fix up some lz4 issues with big
endian systems, and the remaining one resolves a minor debugfs issue
that was reported.
All have been in linux-next with no reported issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-4.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull misc fixes from Greg KH:
"Here are three small fixes for 4.6-rc4.
Two fix up some lz4 issues with big endian systems, and the remaining
one resolves a minor debugfs issue that was reported.
All have been in linux-next with no reported issues"
* tag 'driver-core-4.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
lib: lz4: cleanup unaligned access efficiency detection
lib: lz4: fixed zram with lz4 on big endian machines
debugfs: Make automount point inodes permanently empty
These patches fix f2fs and fscrypto based on -rc3 bug fixes in ext4 crypto,
which have not yet been fully propagated as follows.
- use of dget_parent and file_dentry to avoid crashes
- disallow RCU-mode lookup in d_invalidate
- disallow -ENOMEM in the core data encryption path
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Merge tag 'for-linus-4.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs
Pull f2fs/fscrypto fixes from Jaegeuk Kim:
"In addition to f2fs/fscrypto fixes, I've added one patch which
prevents RCU mode lookup in d_revalidate, as Al mentioned.
These patches fix f2fs and fscrypto based on -rc3 bug fixes in ext4
crypto, which have not yet been fully propagated as follows.
- use of dget_parent and file_dentry to avoid crashes
- disallow RCU-mode lookup in d_invalidate
- disallow -ENOMEM in the core data encryption path"
* tag 'for-linus-4.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs:
ext4/fscrypto: avoid RCU lookup in d_revalidate
fscrypto: don't let data integrity writebacks fail with ENOMEM
f2fs: use dget_parent and file_dentry in f2fs_file_open
fscrypto: use dget_parent() in fscrypt_d_revalidate()
A lot of seqfile users seem to be using things like %pK that uses the
credentials of the current process, but that is actually completely
wrong for filesystem interfaces.
The unix semantics for permission checking files is to check permissions
at _open_ time, not at read or write time, and that is not just a small
detail: passing off stdin/stdout/stderr to a suid application and making
the actual IO happen in privileged context is a classic exploit
technique.
So if we want to be able to look at permissions at read time, we need to
use the file open credentials, not the current ones. Normal file
accesses can just use "f_cred" (or any of the helper functions that do
that, like file_ns_capable()), but the seqfile interfaces do not have
any such options.
It turns out that seq_file _does_ save away the user_ns information of
the file, though. Since user_ns is just part of the full credential
information, replace that special case with saving off the cred pointer
instead, and suddenly seq_file has all the permission information it
needs.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As Al pointed, d_revalidate should return RCU lookup before using d_inode.
This was originally introduced by:
commit 34286d6662 ("fs: rcu-walk aware d_revalidate method").
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: stable <stable@vger.kernel.org>
Starting with 4.1 the tracing subsystem has its own filesystem
which is automounted in the tracing subdirectory of debugfs.
Prior to this debugfs could be bind mounted in a cloned mount
namespace, but if tracefs has been mounted under debugfs this
now fails because there is a locked child mount. This creates
a regression for container software which bind mounts debugfs
to satisfy the assumption of some userspace software.
In other pseudo filesystems such as proc and sysfs we're already
creating mountpoints like this in such a way that no dirents can
be created in the directories, allowing them to be exceptions to
some MNT_LOCKED tests. In fact we're already do this for the
tracefs mountpoint in sysfs.
Do the same in debugfs_create_automount(), since the intention
here is clearly to create a mountpoint. This fixes the regression,
as locked child mounts on permanently empty directories do not
cause a bind mount to fail.
Cc: stable@vger.kernel.org # v4.1+
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fixes the issue introduced by the ext4 crypto fix in a same manner.
For F2FS, however, we flush the pending IOs and wait for a while to acquire free
memory.
Fixes: c9af28fdd4 ("ext4 crypto: don't let data integrity writebacks fail with ENOMEM")
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This patch synced with the below two ext4 crypto fixes together.
In 4.6-rc1, f2fs newly introduced accessing f_path.dentry which crashes
overlayfs. To fix, now we need to use file_dentry() to access that field.
Fixes: c0a37d4878 ("ext4: use file_dentry()")
Fixes: 9dd78d8c9a ("ext4: use dget_parent() in ext4_file_open()")
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This patch updates fscrypto along with the below ext4 crypto change.
Fixes: 3d43bcfef5 ("ext4 crypto: use dget_parent() in ext4_d_revalidate()")
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This reverts commit 1028b55baf.
It's broken: it makes ext4 return an error at an invalid point, causing
the readdir wrappers to write the the position of the last successful
directory entry into the position field, which means that the next
readdir will now return that last successful entry _again_.
You can only return fatal errors (that terminate the readdir directory
walk) from within the filesystem readdir functions, the "normal" errors
(that happen when the readdir buffer fills up, for example) happen in
the iterorator where we know the position of the actual failing entry.
I do have a very different patch that does the "signal_pending()"
handling inside the iterator function where it is allowable, but while
that one passes all the sanity checks, I screwed up something like four
times while emailing it out, so I'm not going to commit it today.
So my track record is not good enough, and the stars will have to align
better before that one gets committed. And it would be good to get some
review too, of course, since celestial alignments are always an iffy
debugging model.
IOW, let's just revert the commit that caused the problem for now.
Reported-by: Greg Thelen <gthelen@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull btrfs fixes from Chris Mason:
"These are bug fixes, including a really old fsync bug, and a few trace
points to help us track down problems in the quota code"
* 'for-linus-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: fix file/data loss caused by fsync after rename and new inode
btrfs: Reset IO error counters before start of device replacing
btrfs: Add qgroup tracing
Btrfs: don't use src fd for printk
btrfs: fallback to vmalloc in btrfs_compare_tree
btrfs: handle non-fatal errors in btrfs_qgroup_inherit()
btrfs: Output more info for enospc_debug mount option
Btrfs: fix invalid reference in replace_path
Btrfs: Improve FL_KEEP_SIZE handling in fallocate
Cleanups:
- remove an unused variable from orangefs_readdir.
- clean up printk wrapper used for ofs "gossip" debugging.
- clean up truncate ctime and mtime setting in inode.c
- remove a useless null check found by coccinelle.
- optimize some memcpy/memset boilerplate code.
- remove some useless sanity checks from xattr.c
Fix:
- fix a potential strncpy vulnerability.
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Merge tag 'for-linus-4.6-ofs1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux
Pull orangefs fixes from Mike Marshall:
"Orangefs cleanups and a strncpy vulnerability fix.
Cleanups:
- remove an unused variable from orangefs_readdir.
- clean up printk wrapper used for ofs "gossip" debugging.
- clean up truncate ctime and mtime setting in inode.c
- remove a useless null check found by coccinelle.
- optimize some memcpy/memset boilerplate code.
- remove some useless sanity checks from xattr.c
Fix:
- fix a potential strncpy vulnerability"
* tag 'for-linus-4.6-ofs1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux:
orangefs: remove unused variable
orangefs: Add KERN_<LEVEL> to gossip_<level> macros
orangefs: strncpy -> strscpy
orangefs: clean up truncate ctime and mtime setting
Orangefs: fix ifnullfree.cocci warnings
Orangefs: optimize boilerplate code.
Orangefs: xattr.c cleanup
Emit the logging messages at the appropriate levels.
Miscellanea:
o Change format to fmt
o Use the more common ##__VA_ARGS__
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>
It would have been possible for a rogue client-core to send in a symlink
target which is not NUL terminated. This returns EIO if the client-core
gives us corrupt data.
Leave debugfs and superblock code as is for now.
Other dcache.c and namei.c strncpy instances are safe because
ORANGEFS_NAME_MAX = NAME_MAX + 1; there is always enough space for a
name plus a NUL byte.
Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>
The ctime and mtime are always updated on a successful ftruncate and
only updated on a successful truncate where the size changed.
We handle the ``if the size changed'' bit.
This matches FUSE's behavior.
Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>
fs/orangefs/orangefs-debugfs.c:130:2-26: WARNING: NULL check before freeing functions like kfree, debugfs_remove, debugfs_remove_recursive or usb_free_urb is not needed. Maybe consider reorganizing relevant code to avoid passing NULL values.
NULL check before some freeing functions is not needed.
Based on checkpatch warning
"kfree(NULL) is safe this check is probably not required"
and kfreeaddr.cocci by Julia Lawall.
Generated by: scripts/coccinelle/free/ifnullfree.cocci
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>
Suggested by David Binderman <dcb314@hotmail.com>
The former can potentially be a performance win over the latter.
memcpy(d, s, len);
memset(d+len, c, size-len);
memset(d, c, size);
memcpy(d, s, len);
Signed-off-by: Mike Marshall <hubcap@omnibond.com>
1. It is nonsense to test for negative size_t, suggested by
David Binderman <dcb314@hotmail.com>
2. By the time Orangefs gets called, the vfs has ensured that
name != NULL, and that buffer and size are sane.
Signed-off-by: Mike Marshall <hubcap@omnibond.com>
(badly behaved) dentry code in various file systems. These have been
reviewed by Al and the respective file system mtinainers and are going
through the ext4 tree for convenience.
This also has a few ext4 encryption bug fixes that were discovered in
Android testing (yes, we will need to get these sync'ed up with the
fs/crypto code; I'll take care of that). It also has some bug fixes
and a change to ignore the legacy quota options to allow for xfstests
regression testing of ext4's internal quota feature and to be more
consistent with how xfs handles this case.
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Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 bugfixes from Ted Ts'o:
"These changes contains a fix for overlayfs interacting with some
(badly behaved) dentry code in various file systems. These have been
reviewed by Al and the respective file system mtinainers and are going
through the ext4 tree for convenience.
This also has a few ext4 encryption bug fixes that were discovered in
Android testing (yes, we will need to get these sync'ed up with the
fs/crypto code; I'll take care of that). It also has some bug fixes
and a change to ignore the legacy quota options to allow for xfstests
regression testing of ext4's internal quota feature and to be more
consistent with how xfs handles this case"
* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: ignore quota mount options if the quota feature is enabled
ext4 crypto: fix some error handling
ext4: avoid calling dquot_get_next_id() if quota is not enabled
ext4: retry block allocation for failed DIO and DAX writes
ext4: add lockdep annotations for i_data_sem
ext4: allow readdir()'s of large empty directories to be interrupted
btrfs: fix crash/invalid memory access on fsync when using overlayfs
ext4 crypto: use dget_parent() in ext4_d_revalidate()
ext4: use file_dentry()
ext4: use dget_parent() in ext4_file_open()
nfs: use file_dentry()
fs: add file_dentry()
ext4 crypto: don't let data integrity writebacks fail with ENOMEM
ext4: check if in-inode xattr is corrupted in ext4_expand_extra_isize_ea()
If we rename an inode A (be it a file or a directory), create a new
inode B with the old name of inode A and under the same parent directory,
fsync inode B and then power fail, at log tree replay time we end up
removing inode A completely. If inode A is a directory then all its files
are gone too.
Example scenarios where this happens:
This is reproducible with the following steps, taken from a couple of
test cases written for fstests which are going to be submitted upstream
soon:
# Scenario 1
mkfs.btrfs -f /dev/sdc
mount /dev/sdc /mnt
mkdir -p /mnt/a/x
echo "hello" > /mnt/a/x/foo
echo "world" > /mnt/a/x/bar
sync
mv /mnt/a/x /mnt/a/y
mkdir /mnt/a/x
xfs_io -c fsync /mnt/a/x
<power failure happens>
The next time the fs is mounted, log tree replay happens and
the directory "y" does not exist nor do the files "foo" and
"bar" exist anywhere (neither in "y" nor in "x", nor the root
nor anywhere).
# Scenario 2
mkfs.btrfs -f /dev/sdc
mount /dev/sdc /mnt
mkdir /mnt/a
echo "hello" > /mnt/a/foo
sync
mv /mnt/a/foo /mnt/a/bar
echo "world" > /mnt/a/foo
xfs_io -c fsync /mnt/a/foo
<power failure happens>
The next time the fs is mounted, log tree replay happens and the
file "bar" does not exists anymore. A file with the name "foo"
exists and it matches the second file we created.
Another related problem that does not involve file/data loss is when a
new inode is created with the name of a deleted snapshot and we fsync it:
mkfs.btrfs -f /dev/sdc
mount /dev/sdc /mnt
mkdir /mnt/testdir
btrfs subvolume snapshot /mnt /mnt/testdir/snap
btrfs subvolume delete /mnt/testdir/snap
rmdir /mnt/testdir
mkdir /mnt/testdir
xfs_io -c fsync /mnt/testdir # or fsync some file inside /mnt/testdir
<power failure>
The next time the fs is mounted the log replay procedure fails because
it attempts to delete the snapshot entry (which has dir item key type
of BTRFS_ROOT_ITEM_KEY) as if it were a regular (non-root) entry,
resulting in the following error that causes mount to fail:
[52174.510532] BTRFS info (device dm-0): failed to delete reference to snap, inode 257 parent 257
[52174.512570] ------------[ cut here ]------------
[52174.513278] WARNING: CPU: 12 PID: 28024 at fs/btrfs/inode.c:3986 __btrfs_unlink_inode+0x178/0x351 [btrfs]()
[52174.514681] BTRFS: Transaction aborted (error -2)
[52174.515630] Modules linked in: btrfs dm_flakey dm_mod overlay crc32c_generic ppdev xor raid6_pq acpi_cpufreq parport_pc tpm_tis sg parport tpm evdev i2c_piix4 proc
[52174.521568] CPU: 12 PID: 28024 Comm: mount Tainted: G W 4.5.0-rc6-btrfs-next-27+ #1
[52174.522805] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[52174.524053] 0000000000000000 ffff8801df2a7710 ffffffff81264e93 ffff8801df2a7758
[52174.524053] 0000000000000009 ffff8801df2a7748 ffffffff81051618 ffffffffa03591cd
[52174.524053] 00000000fffffffe ffff88015e6e5000 ffff88016dbc3c88 ffff88016dbc3c88
[52174.524053] Call Trace:
[52174.524053] [<ffffffff81264e93>] dump_stack+0x67/0x90
[52174.524053] [<ffffffff81051618>] warn_slowpath_common+0x99/0xb2
[52174.524053] [<ffffffffa03591cd>] ? __btrfs_unlink_inode+0x178/0x351 [btrfs]
[52174.524053] [<ffffffff81051679>] warn_slowpath_fmt+0x48/0x50
[52174.524053] [<ffffffffa03591cd>] __btrfs_unlink_inode+0x178/0x351 [btrfs]
[52174.524053] [<ffffffff8118f5e9>] ? iput+0xb0/0x284
[52174.524053] [<ffffffffa0359fe8>] btrfs_unlink_inode+0x1c/0x3d [btrfs]
[52174.524053] [<ffffffffa038631e>] check_item_in_log+0x1fe/0x29b [btrfs]
[52174.524053] [<ffffffffa0386522>] replay_dir_deletes+0x167/0x1cf [btrfs]
[52174.524053] [<ffffffffa038739e>] fixup_inode_link_count+0x289/0x2aa [btrfs]
[52174.524053] [<ffffffffa038748a>] fixup_inode_link_counts+0xcb/0x105 [btrfs]
[52174.524053] [<ffffffffa038a5ec>] btrfs_recover_log_trees+0x258/0x32c [btrfs]
[52174.524053] [<ffffffffa03885b2>] ? replay_one_extent+0x511/0x511 [btrfs]
[52174.524053] [<ffffffffa034f288>] open_ctree+0x1dd4/0x21b9 [btrfs]
[52174.524053] [<ffffffffa032b753>] btrfs_mount+0x97e/0xaed [btrfs]
[52174.524053] [<ffffffff8108e1b7>] ? trace_hardirqs_on+0xd/0xf
[52174.524053] [<ffffffff8117bafa>] mount_fs+0x67/0x131
[52174.524053] [<ffffffff81193003>] vfs_kern_mount+0x6c/0xde
[52174.524053] [<ffffffffa032af81>] btrfs_mount+0x1ac/0xaed [btrfs]
[52174.524053] [<ffffffff8108e1b7>] ? trace_hardirqs_on+0xd/0xf
[52174.524053] [<ffffffff8108c262>] ? lockdep_init_map+0xb9/0x1b3
[52174.524053] [<ffffffff8117bafa>] mount_fs+0x67/0x131
[52174.524053] [<ffffffff81193003>] vfs_kern_mount+0x6c/0xde
[52174.524053] [<ffffffff8119590f>] do_mount+0x8a6/0x9e8
[52174.524053] [<ffffffff811358dd>] ? strndup_user+0x3f/0x59
[52174.524053] [<ffffffff81195c65>] SyS_mount+0x77/0x9f
[52174.524053] [<ffffffff814935d7>] entry_SYSCALL_64_fastpath+0x12/0x6b
[52174.561288] ---[ end trace 6b53049efb1a3ea6 ]---
Fix this by forcing a transaction commit when such cases happen.
This means we check in the commit root of the subvolume tree if there
was any other inode with the same reference when the inode we are
fsync'ing is a new inode (created in the current transaction).
Test cases for fstests, covering all the scenarios given above, were
submitted upstream for fstests:
* fstests: generic test for fsync after renaming directory
https://patchwork.kernel.org/patch/8694281/
* fstests: generic test for fsync after renaming file
https://patchwork.kernel.org/patch/8694301/
* fstests: add btrfs test for fsync after snapshot deletion
https://patchwork.kernel.org/patch/8670671/
Cc: stable@vger.kernel.org
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Pull quota fixes from Jan Kara:
"Fixes for oopses when the new quotactl gets used with quotas disabled"
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
ocfs2: Fix Q_GETNEXTQUOTA for filesystem without quotas
quota: Handle Q_GETNEXTQUOTA when quota is disabled
Pull f2fs fixes from Jaegeuk Kim.
* tag 'f2fs-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs:
f2fs: retrieve IO write stat from the right place
f2fs crypto: fix corrupted symlink in encrypted case
f2fs: cover large section in sanity check of super
