When we close a file, we remove preallocated blocks from it. But this
truncation was not protected by i_mutex and thus it could have raced with a
write through a different fd and cause crashes or even filesystem corruption.
Signed-off-by: Jan Kara <jack@suse.cz>
So far we preallocated blocks also for directories but that brings a
problem, when to get rid of preallocated blocks we don't need. So far
we removed them in udf_clear_inode() which has a disadvantage that
1) blocks are unavailable long after writing to a directory finished
and thus one can get out of space unnecessarily early
2) releasing blocks from udf_clear_inode is problematic because VFS
does not expect us to redirty inode there and it also slows down
memory reclaim.
So preallocate blocks only for regular files where we can drop preallocation
in udf_release_file.
Signed-off-by: Jan Kara <jack@suse.cz>
Recomputation of the pointer was wrong (it should have been just increment).
Luckily, we never use the computed value. Remove it.
Signed-off-by: Jan Kara <jack@suse.cz>
Currenly vfs_fsync(_range) first calls filemap_fdatawrite to write out
the data, the calls into ->fsync to write out the metadata and then finally
calls filemap_fdatawait to wait for the data I/O to complete. What sounds
like a clever micro-optimization actually is nast trap for many filesystems.
For many modern filesystems i_size or other inode information is only
updated on I/O completion and we need to wait for I/O to finish before
we can write out the metadata. For old fashionen filesystems that
instanciate blocks during the actual write and also update the metadata
at that point it opens up a large window were we could expose uninitialized
blocks after a crash. While a few filesystems that need it already wait
for the I/O to finish inside their ->fsync methods it is rather suboptimal
as it is done under the i_mutex and also always for the whole file instead
of just a part as we could do for O_SYNC handling.
Here is a small audit of all fsync instances in the tree:
- spufs_mfc_fsync:
- ps3flash_fsync:
- vol_cdev_fsync:
- printer_fsync:
- fb_deferred_io_fsync:
- bad_file_fsync:
- simple_sync_file:
don't care - filesystems/drivers do't use the page cache or are
purely in-memory.
- simple_fsync:
- file_fsync:
- affs_file_fsync:
- fat_file_fsync:
- jfs_fsync:
- ubifs_fsync:
- reiserfs_dir_fsync:
- reiserfs_sync_file:
never touch pagecache themselves. We need to wait before if we do
not want to expose stale data after an allocation.
- afs_fsync:
- fuse_fsync_common:
do the waiting writeback itself in awkward ways, would benefit from
proper semantics
- block_fsync:
Does a filemap_write_and_wait on the block device inode. Because we
now have f_mapping that is the same inode we call it on in vfs_fsync.
So just removing it and letting the VFS do the work in one go would
be an improvement.
- btrfs_sync_file:
- cifs_fsync:
- xfs_file_fsync:
need the wait first and currently do it themselves. would benefit from
doing it outside i_mutex.
- coda_fsync:
- ecryptfs_fsync:
- exofs_file_fsync:
- shm_fsync:
only passes the fsync through to the lower layer
- ext3_sync_file:
doesn't seem to care, comments are confusing.
- ext4_sync_file:
would need the wait to work correctly for delalloc mode with late
i_size updates. Otherwise the ext3 comment applies.
currently implemens it's own writeback and wait in an odd way,
could benefit from doing it properly.
- gfs2_fsync:
not needed for journaled data mode, but probably harmless there.
Currently writes back data asynchronously itself. Needs some
major audit.
- hostfs_fsync:
just calls fsync/datasync on the host FD. Without the wait before
data might not even be inflight yet if we're unlucky.
- hpfs_file_fsync:
- ncp_fsync:
no-ops. Dangerous before and after.
- jffs2_fsync:
just calls jffs2_flush_wbuf_gc, not sure how this relates to data.
- nfs_fsync_dir:
just increments stats, claims all directory operations are synchronous
- nfs_file_fsync:
only writes out data??? Looks very odd.
- nilfs_sync_file:
looks like it expects all data done, but not sure from the code
- ntfs_dir_fsync:
- ntfs_file_fsync:
appear to do their own data writeback. Very convoluted code.
- ocfs2_sync_file:
does it's own data writeback, but no wait. probably needs the wait.
- smb_fsync:
according to a comment expects all pages written already, probably needs
the wait before.
This patch only changes vfs_fsync_range, removal of the wait in the methods
that have it is left to the filesystem maintainers. Note that most
filesystems really do need an audit for their fsync methods given the
gems found in this very brief audit.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
fat_cont_expand() is the only user of sync_page_range_nolock(). It's also the
only user of generic_osync_inode() which does not have a file open. So
opencode needed actions for FAT so that we can convert generic_osync_inode() to
a standard syncing path.
Update a comment about generic_osync_inode().
CC: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Jan Kara <jack@suse.cz>
Christoph Hellwig says that it is enough for XFS to call
filemap_write_and_wait_range() instead of sync_page_range() because we do
all the metadata syncing when forcing the log.
CC: Felix Blyakher <felixb@sgi.com>
CC: xfs@oss.sgi.com
CC: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Update ocfs2 specific splicing code to use generic syncing helper. The sync now
does not happen under rw_lock because generic_write_sync() acquires i_mutex
which ranks above rw_lock. That should not matter because standard fsync path
does not hold it either.
Acked-by: Joel Becker <Joel.Becker@oracle.com>
Acked-by: Mark Fasheh <mfasheh@suse.com>
CC: ocfs2-devel@oss.oracle.com
Signed-off-by: Jan Kara <jack@suse.cz>
Use new syncing helpers in .write and .aio_write functions. Also
remove superfluous syncing in ntfs_file_buffered_write() and update
comments about generic_osync_inode().
CC: Anton Altaparmakov <aia21@cantab.net>
CC: linux-ntfs-dev@lists.sourceforge.net
Signed-off-by: Jan Kara <jack@suse.cz>
The syncing is now properly handled by generic_file_aio_write() so
no special ext4 code is needed.
CC: linux-ext4@vger.kernel.org
CC: tytso@mit.edu
Signed-off-by: Jan Kara <jack@suse.cz>
Syncing is now properly done by generic_file_aio_write() so no special logic is
needed in ext3.
CC: linux-ext4@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Introduce new function for generic inode syncing (vfs_fsync_range) and use
it from fsync() path. Introduce also new helper for syncing after a sync
write (generic_write_sync) using the generic function.
Use these new helpers for syncing from generic VFS functions. This makes
O_SYNC writes to block devices acquire i_mutex for syncing. If we really
care about this, we can make block_fsync() drop the i_mutex and reacquire
it before it returns.
CC: Evgeniy Polyakov <zbr@ioremap.net>
CC: ocfs2-devel@oss.oracle.com
CC: Joel Becker <joel.becker@oracle.com>
CC: Felix Blyakher <felixb@sgi.com>
CC: xfs@oss.sgi.com
CC: Anton Altaparmakov <aia21@cantab.net>
CC: linux-ntfs-dev@lists.sourceforge.net
CC: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
CC: linux-ext4@vger.kernel.org
CC: tytso@mit.edu
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
generic_file_aio_write_nolock() is now used only by block devices and raw
character device. Filesystems should use __generic_file_aio_write() in case
generic_file_aio_write() doesn't suit them. So rename the function to
blkdev_aio_write() and move it to fs/blockdev.c.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Use the new helper. We have to submit data pages ourselves in case of O_SYNC
write because __generic_file_aio_write does not do it for us. OCFS2 developpers
might think about moving the sync out of i_mutex which seems to be easily
possible but that's out of scope of this patch.
CC: ocfs2-devel@oss.oracle.com
Acked-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Some people asked me questions like the following:
On Wed, 15 Jul 2009 13:11:21 +0200, Leon Woestenberg wrote:
> just wondering, any reasons why NILFS2 is one of the miscellaneous
> filesystems and, for example, btrfs, is not in Kconfig?
Actually, nilfs is NOT a filesystem came from other operating systems,
but a filesystem created purely for Linux. Nor is it a flash
filesystem but that for generic block devices.
So, this moves nilfs outside the misc category as I responded in LKML
"Re: Why does NILFS2 hide under Miscellaneous filesystems?"
(Message-Id: <20090716.002526.93465395.ryusuke@osrg.net>).
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
The nilfs_bmap_lookup() is now a wrapper function of
nilfs_bmap_lookup_at_level().
This moves the nilfs_bmap_lookup() to a header file converting it to
an inline function and gives an opportunity for optimization.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
The current btree code is written so that btree functions call dat
operations via wrapper functions in bmap.c when they allocate, free,
or modify virtual block addresses.
This abstraction requires additional function calls and causes
frequent call of nilfs_bmap_get_dat() function since it is used in the
every wrapper function.
This removes the wrapper functions and makes them available from
btree.c and direct.c, which will increase the opportunity of
compiler optimization.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This is a preparation for the successive cleanup ("nilfs2: allow btree
to directly call dat operations").
This adds functions bundling a few operations to change an entry of
virtual block address on the dat file.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This gets rid of NILFS_CPFILE_GFP, NILFS_SUFILE_GFP, NILFS_DAT_GFP,
and NILFS_IFILE_GFP. All of these constants refer to NILFS_MDT_GFP,
and can be removed.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
The btree path object is cleared just before it is freed.
This will remove the code doing the unnecessary clear operation.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Even though many btree functions take a btree object as their first
argument, most of them are not used in their functions.
This sticky use of the btree argument is hurting code readability and
giving the possibility of inefficient code generation.
So, this removes the unnecessary btree arguments.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This is a re-revised patch to shorten freeze period.
This version include a fix of the bug Konishi-san mentioned last time.
When GC is runnning, GC moves live block to difference segments.
Copying live blocks into memory is done in a transaction,
however it is not necessarily to be in the transaction.
This patch will get the nilfs_ioctl_move_blocks() out from
transaction lock and put it before the transaction.
I ran sysbench fileio test against nilfs partition.
I copied some DVD/CD images and created snapshot to create live blocks
before starting the benchmark.
Followings are summary of rc8 and rc8 w/ the patch of per-request
statistics, which is min/max and avg. I ran each test three times and
bellow is average of those numers.
According to this benchmark result, average time is slightly degrated.
However, worstcase (max) result is significantly improved.
This can address a few seconds write freeze.
- random write per-request performance of rc8
min 0.843ms
max 680.406ms
avg 3.050ms
- random write per-request performance of rc8 w/ this patch
min 0.843ms -> 100.00%
max 380.490ms -> 55.90%
avg 3.233ms -> 106.00%
- sequential write per-request performance of rc8
min 0.736ms
max 774.343ms
avg 2.883ms
- sequential write per-request performance of rc8 w/ this patch
min 0.720ms -> 97.80%
max 644.280ms-> 83.20%
avg 3.130ms -> 108.50%
-----8<-----8<-----nilfs_cleanerd.conf-----8<-----8<-----
protection_period 150
selection_policy timestamp # timestamp in ascend order
nsegments_per_clean 2
cleaning_interval 2
retry_interval 60
use_mmap
log_priority info
-----8<-----8<-----nilfs_cleanerd.conf-----8<-----8<-----
Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
nilfs2: Add more safeguard routines and protections in mount process,
which also makes nilfs2 report consistency error messages when
checkpoint number is invalid.
Signed-off-by: Zhu Yanhai <zhu.yanhai@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
nilfs2: In procedure 'nilfs_get_sb()', when a nilfs filesysttem is
mounted for the first time, local variable 'nilfs->ns_last_cno' is
used before loading the latest checkpoint number from disk (in
'nilfs_fill_super'). 'nilfs->ns_last_cno' is assigned to 'sd.cno', but
'sd.cno' has never been used in the procedure.
Signed-off-by: Zhang Qiang <zhangqiang.buaa@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Alberto Bertogli advised me about bio_alloc() use in nilfs:
On Sat, 13 Jun 2009 22:52:40 -0300, Alberto Bertogli wrote:
> By the way, those bio_alloc()s are using GFP_NOWAIT but it looks
> like they could use at least GFP_NOIO or GFP_NOFS, since the caller
> can (and sometimes do) sleep. The only caller is nilfs_submit_bh(),
> which calls nilfs_submit_seg_bio() which can sleep calling
> wait_for_completion().
This takes in the comment and replaces the use of GFP_NOWAIT flag with
GFP_NOIO.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This removes nilfs_write_super and commit super block in nilfs
internal thread, instead of periodic write_super callback.
VFS layer calls ->write_super callback periodically. However,
it looks like that calling back is ommited when disk I/O is busy.
And when cleanerd (nilfs GC) is runnig, disk I/O tend to be busy thus
nilfs superblock is not synchronized as nilfs designed.
To avoid it, syncing superblock by nilfs thread instead of pdflush.
Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Separate conditions that check if syncing super block and alternative
super block are required as inline functions to reuse the conditions.
Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This fixes disorder of nilfs_write_super in nilfs_sync_fs. Commiting
super block must be the end of the function so that every changes are
reflected.
->sync_fs() is not called frequently so this makes nilfs_sync_fs call
nilfs_commit_super instead of nilfs_write_super.
Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This removes redundant super block commit.
nilfs_write_super will call nilfs_commit_super to store super block
into block device. However, nilfs_put_super will call
nilfs_commit_super right after calling nilfs_write_super. So calling
nilfs_write_super in nilfs_put_super would be redundant.
Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This is a patch to display mount options in procfs.
Mount options will show up in the /proc/mounts as other fs does.
...
/dev/sda6 /mnt nilfs2 ro,relatime,barrier=off,cp=3,order=strict 0 0
...
Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
The current metadata file code skips disk address lookup for its data
block if the buffer has a mapped flag.
This has a potential risk to cause read request to be performed
against the stale block address that GC moved, and it may lead to meta
data corruption. The mapped flag is safe if the buffer has an
uptodate flag, otherwise it may prevent necessary update of disk
address in the next read.
This will avoid the potential problem by ensuring disk address lookup
before reading metadata block even for buffers with the mapped flag.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
will get rid of nilfs_get_writer() and nilfs_put_writer() pair used to
retain a writable FS-instance for a period.
The pair functions were making up some kind of recursive lock with a
mutex, but they became overkill since the commit
201913ed74. Furthermore, they caused
the following lockdep warning because the mutex can be released by a
task which didn't lock it:
=====================================
[ BUG: bad unlock balance detected! ]
-------------------------------------
kswapd0/422 is trying to release lock (&nilfs->ns_writer_mutex) at:
[<c1359ff5>] mutex_unlock+0x8/0xa
but there are no more locks to release!
other info that might help us debug this:
no locks held by kswapd0/422.
stack backtrace:
Pid: 422, comm: kswapd0 Not tainted 2.6.31-rc4-nilfs #51
Call Trace:
[<c1358f97>] ? printk+0xf/0x18
[<c104fea7>] print_unlock_inbalance_bug+0xcc/0xd7
[<c11578de>] ? prop_put_global+0x3/0x35
[<c1050195>] lock_release+0xed/0x1dc
[<c1359ff5>] ? mutex_unlock+0x8/0xa
[<c1359f83>] __mutex_unlock_slowpath+0xaf/0x119
[<c1359ff5>] mutex_unlock+0x8/0xa
[<d1284add>] nilfs_mdt_write_page+0xd8/0xe1 [nilfs2]
[<c1092653>] shrink_page_list+0x379/0x68d
[<c109171b>] ? isolate_pages_global+0xb4/0x18c
[<c1092bd2>] shrink_list+0x26b/0x54b
[<c10930be>] shrink_zone+0x20c/0x2a2
[<c10936b7>] kswapd+0x407/0x591
[<c1091667>] ? isolate_pages_global+0x0/0x18c
[<c1040603>] ? autoremove_wake_function+0x0/0x33
[<c10932b0>] ? kswapd+0x0/0x591
[<c104033b>] kthread+0x69/0x6e
[<c10402d2>] ? kthread+0x0/0x6e
[<c1003e33>] kernel_thread_helper+0x7/0x1a
This patch uses a reader/writer semaphore instead of the own lock and
kills this warning.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Unlike on most other architectures ino_t is an unsigned int on s390.
So add an explicit cast to avoid this compile warning:
fs/nilfs2/recovery.c: In function 'recover_dsync_blocks':
fs/nilfs2/recovery.c:555: warning: format '%lu' expects type 'long unsigned int', but argument 3 has type 'ino_t'
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
The __nilfs_read_inode function is ignoring the error code returned
from nilfs_read_inode_common(), and wrongly delivers a success code
(zero) when it escapes from the function in erroneous cases.
This adds the missing error handling.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Also a debugging aid. We want to catch dirty inodes being added to
backing devices that don't do writeback.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This enables us to track who does what and print info. Its main use
is catching dirty inodes on the default_backing_dev_info, so we can
fix that up.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This gets rid of pdflush for bdi writeout and kupdated style cleaning.
pdflush writeout suffers from lack of locality and also requires more
threads to handle the same workload, since it has to work in a
non-blocking fashion against each queue. This also introduces lumpy
behaviour and potential request starvation, since pdflush can be starved
for queue access if others are accessing it. A sample ffsb workload that
does random writes to files is about 8% faster here on a simple SATA drive
during the benchmark phase. File layout also seems a LOT more smooth in
vmstat:
r b swpd free buff cache si so bi bo in cs us sy id wa
0 1 0 608848 2652 375372 0 0 0 71024 604 24 1 10 48 42
0 1 0 549644 2712 433736 0 0 0 60692 505 27 1 8 48 44
1 0 0 476928 2784 505192 0 0 4 29540 553 24 0 9 53 37
0 1 0 457972 2808 524008 0 0 0 54876 331 16 0 4 38 58
0 1 0 366128 2928 614284 0 0 4 92168 710 58 0 13 53 34
0 1 0 295092 3000 684140 0 0 0 62924 572 23 0 9 53 37
0 1 0 236592 3064 741704 0 0 4 58256 523 17 0 8 48 44
0 1 0 165608 3132 811464 0 0 0 57460 560 21 0 8 54 38
0 1 0 102952 3200 873164 0 0 4 74748 540 29 1 10 48 41
0 1 0 48604 3252 926472 0 0 0 53248 469 29 0 7 47 45
where vanilla tends to fluctuate a lot in the creation phase:
r b swpd free buff cache si so bi bo in cs us sy id wa
1 1 0 678716 5792 303380 0 0 0 74064 565 50 1 11 52 36
1 0 0 662488 5864 319396 0 0 4 352 302 329 0 2 47 51
0 1 0 599312 5924 381468 0 0 0 78164 516 55 0 9 51 40
0 1 0 519952 6008 459516 0 0 4 78156 622 56 1 11 52 37
1 1 0 436640 6092 541632 0 0 0 82244 622 54 0 11 48 41
0 1 0 436640 6092 541660 0 0 0 8 152 39 0 0 51 49
0 1 0 332224 6200 644252 0 0 4 102800 728 46 1 13 49 36
1 0 0 274492 6260 701056 0 0 4 12328 459 49 0 7 50 43
0 1 0 211220 6324 763356 0 0 0 106940 515 37 1 10 51 39
1 0 0 160412 6376 813468 0 0 0 8224 415 43 0 6 49 45
1 1 0 85980 6452 886556 0 0 4 113516 575 39 1 11 54 34
0 2 0 85968 6452 886620 0 0 0 1640 158 211 0 0 46 54
A 10 disk test with btrfs performs 26% faster with per-bdi flushing. A
SSD based writeback test on XFS performs over 20% better as well, with
the throughput being very stable around 1GB/sec, where pdflush only
manages 750MB/sec and fluctuates wildly while doing so. Random buffered
writes to many files behave a lot better as well, as does random mmap'ed
writes.
A separate thread is added to sync the super blocks. In the long term,
adding sync_supers_bdi() functionality could get rid of this thread again.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This is a first step at introducing per-bdi flusher threads. We should
have no change in behaviour, although sb_has_dirty_inodes() is now
ridiculously expensive, as there's no easy way to answer that question.
Not a huge problem, since it'll be deleted in subsequent patches.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This adds two new exported functions:
- writeback_inodes_sb(), which only attempts to writeback dirty inodes on
this super_block, for WB_SYNC_NONE writeout.
- sync_inodes_sb(), which writes out all dirty inodes on this super_block
and also waits for the IO to complete.
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
In fs/binfmt_elf.c, load_elf_interp() calls padzero() for .bss even if
the PT_LOAD has no PROT_WRITE and no .bss. This generates EFAULT.
Here is a small test case. (Yes, there are other, useful PT_INTERP
which have only .text and no .data/.bss.)
----- ptinterp.S
_start: .globl _start
nop
int3
-----
$ gcc -m32 -nostartfiles -nostdlib -o ptinterp ptinterp.S
$ gcc -m32 -Wl,--dynamic-linker=ptinterp -o hello hello.c
$ ./hello
Segmentation fault # during execve() itself
After applying the patch:
$ ./hello
Trace trap # user-mode execution after execve() finishes
If the ELF headers are actually self-inconsistent, then dying is fine.
But having no PROT_WRITE segment is perfectly normal and correct if
there is no segment with p_memsz > p_filesz (i.e. bss). John Reiser
suggested checking for PROT_WRITE in the bss logic. I think it makes
most sense to simply apply the bss logic only when there is bss.
This patch looks less trivial than it is due to some reindentation.
It just moves the "if (last_bss > elf_bss) {" test up to include the
partial-page bss logic as well as the more-pages bss logic.
Reported-by: John Reiser <jreiser@bitwagon.com>
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
In fs/binfmt_elf.c, load_elf_interp() calls padzero() for .bss even if
the PT_LOAD has no PROT_WRITE and no .bss. This generates EFAULT.
Here is a small test case. (Yes, there are other, useful PT_INTERP
which have only .text and no .data/.bss.)
----- ptinterp.S
_start: .globl _start
nop
int3
-----
$ gcc -m32 -nostartfiles -nostdlib -o ptinterp ptinterp.S
$ gcc -m32 -Wl,--dynamic-linker=ptinterp -o hello hello.c
$ ./hello
Segmentation fault # during execve() itself
After applying the patch:
$ ./hello
Trace trap # user-mode execution after execve() finishes
If the ELF headers are actually self-inconsistent, then dying is fine.
But having no PROT_WRITE segment is perfectly normal and correct if
there is no segment with p_memsz > p_filesz (i.e. bss). John Reiser
suggested checking for PROT_WRITE in the bss logic. I think it makes
most sense to simply apply the bss logic only when there is bss.
This patch looks less trivial than it is due to some reindentation.
It just moves the "if (last_bss > elf_bss) {" test up to include the
partial-page bss logic as well as the more-pages bss logic.
Reported-by: John Reiser <jreiser@bitwagon.com>
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds a setxattr handler to the file, directory, and symlink
inode_operations structures for sysfs. The patch uses hooks introduced in the
previous patch to handle the getting and setting of security information for
the sysfs inodes. As was suggested by Eric Biederman the struct iattr in the
sysfs_dirent structure has been replaced by a structure which contains the
iattr, secdata and secdata length to allow the changes to persist in the event
that the inode representing the sysfs_dirent is evicted. Because sysfs only
stores this information when a change is made all the optional data is moved
into one dynamically allocated field.
This patch addresses an issue where SELinux was denying virtd access to the PCI
configuration entries in sysfs. The lack of setxattr handlers for sysfs
required that a single label be assigned to all entries in sysfs. Granting virtd
access to every entry in sysfs is not an acceptable solution so fine grained
labeling of sysfs is required such that individual entries can be labeled
appropriately.
[sds: Fixed compile-time warnings, coding style, and setting of inode security init flags.]
Signed-off-by: David P. Quigley <dpquigl@tycho.nsa.gov>
Signed-off-by: Stephen D. Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
This factors out the part of the vfs_setxattr function that performs the
setting of the xattr and its notification. This is needed so the SELinux
implementation of inode_setsecctx can handle the setting of the xattr while
maintaining the proper separation of layers.
Signed-off-by: David P. Quigley <dpquigl@tycho.nsa.gov>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
The /sys/fs/gfs2/<fsname>/lock_module/id file has been unused for
some time now, so we can remove it. We still accept the mount option
though, as userspace still sends that.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Jan Kara