29 Jun, 2013
2 commits
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Instances either don't look at it at all (the majority of cases) or
only want it to find the superblock (which can be had as dentry->d_sb).
A few cases that want more are actually safe with dentry->d_inode -
the only precaution needed is the check that it hadn't been replaced with
NULL by rmdir() or by overwriting rename(), which case should be simply
treated as cache miss.Signed-off-by: Linus Torvalds
Signed-off-by: Al Viro -
ext2, ufs, minix, sysv
Signed-off-by: Al Viro
13 Mar, 2013
1 commit
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I had assumed that the only use of module aliases for filesystems
prior to "fs: Limit sys_mount to only request filesystem modules."
was in request_module. It turns out I was wrong. At least mkinitcpio
in Arch linux uses these aliases.So readd the preexising aliases, to keep from breaking userspace.
Userspace eventually will have to follow and use the same aliases the
kernel does. So at some point we may be delete these aliases without
problems. However that day is not today.Signed-off-by: "Eric W. Biederman"
04 Mar, 2013
1 commit
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Modify the request_module to prefix the file system type with "fs-"
and add aliases to all of the filesystems that can be built as modules
to match.A common practice is to build all of the kernel code and leave code
that is not commonly needed as modules, with the result that many
users are exposed to any bug anywhere in the kernel.Looking for filesystems with a fs- prefix limits the pool of possible
modules that can be loaded by mount to just filesystems trivially
making things safer with no real cost.Using aliases means user space can control the policy of which
filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
with blacklist and alias directives. Allowing simple, safe,
well understood work-arounds to known problematic software.This also addresses a rare but unfortunate problem where the filesystem
name is not the same as it's module name and module auto-loading
would not work. While writing this patch I saw a handful of such
cases. The most significant being autofs that lives in the module
autofs4.This is relevant to user namespaces because we can reach the request
module in get_fs_type() without having any special permissions, and
people get uncomfortable when a user specified string (in this case
the filesystem type) goes all of the way to request_module.After having looked at this issue I don't think there is any
particular reason to perform any filtering or permission checks beyond
making it clear in the module request that we want a filesystem
module. The common pattern in the kernel is to call request_module()
without regards to the users permissions. In general all a filesystem
module does once loaded is call register_filesystem() and go to sleep.
Which means there is not much attack surface exposed by loading a
filesytem module unless the filesystem is mounted. In a user
namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
which most filesystems do not set today.Acked-by: Serge Hallyn
Acked-by: Kees Cook
Reported-by: Kees Cook
Signed-off-by: "Eric W. Biederman"
23 Feb, 2013
1 commit
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Signed-off-by: Al Viro
21 Dec, 2012
1 commit
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Removed vmtruncate
Signed-off-by: Marco Stornelli
Signed-off-by: Al Viro
10 Oct, 2012
1 commit
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Removed lock/unlock super. Added a new private s_lock mutex.
Signed-off-by: Marco Stornelli
Signed-off-by: Al Viro
03 Oct, 2012
2 commits
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Pull vfs update from Al Viro:
- big one - consolidation of descriptor-related logics; almost all of
that is moved to fs/file.c(BTW, I'm seriously tempted to rename the result to fd.c. As it is,
we have a situation when file_table.c is about handling of struct
file and file.c is about handling of descriptor tables; the reasons
are historical - file_table.c used to be about a static array of
struct file we used to have way back).A lot of stray ends got cleaned up and converted to saner primitives,
disgusting mess in android/binder.c is still disgusting, but at least
doesn't poke so much in descriptor table guts anymore. A bunch of
relatively minor races got fixed in process, plus an ext4 struct file
leak.- related thing - fget_light() partially unuglified; see fdget() in
there (and yes, it generates the code as good as we used to have).- also related - bits of Cyrill's procfs stuff that got entangled into
that work; _not_ all of it, just the initial move to fs/proc/fd.c and
switch of fdinfo to seq_file.- Alex's fs/coredump.c spiltoff - the same story, had been easier to
take that commit than mess with conflicts. The rest is a separate
pile, this was just a mechanical code movement.- a few misc patches all over the place. Not all for this cycle,
there'll be more (and quite a few currently sit in akpm's tree)."Fix up trivial conflicts in the android binder driver, and some fairly
simple conflicts due to two different changes to the sock_alloc_file()
interface ("take descriptor handling from sock_alloc_file() to callers"
vs "net: Providing protocol type via system.sockprotoname xattr of
/proc/PID/fd entries" adding a dentry name to the socket)* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (72 commits)
MAX_LFS_FILESIZE should be a loff_t
compat: fs: Generic compat_sys_sendfile implementation
fs: push rcu_barrier() from deactivate_locked_super() to filesystems
btrfs: reada_extent doesn't need kref for refcount
coredump: move core dump functionality into its own file
coredump: prevent double-free on an error path in core dumper
usb/gadget: fix misannotations
fcntl: fix misannotations
ceph: don't abuse d_delete() on failure exits
hypfs: ->d_parent is never NULL or negative
vfs: delete surplus inode NULL check
switch simple cases of fget_light to fdget
new helpers: fdget()/fdput()
switch o2hb_region_dev_write() to fget_light()
proc_map_files_readdir(): don't bother with grabbing files
make get_file() return its argument
vhost_set_vring(): turn pollstart/pollstop into bool
switch prctl_set_mm_exe_file() to fget_light()
switch xfs_find_handle() to fget_light()
switch xfs_swapext() to fget_light()
... -
There's no reason to call rcu_barrier() on every
deactivate_locked_super(). We only need to make sure that all delayed rcu
free inodes are flushed before we destroy related cache.Removing rcu_barrier() from deactivate_locked_super() affects some fast
paths. E.g. on my machine exit_group() of a last process in IPC
namespace takes 0.07538s. rcu_barrier() takes 0.05188s of that time.Signed-off-by: Kirill A. Shutemov
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Al Viro
21 Sep, 2012
1 commit
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Cc: Christoph Hellwig
Acked-by: Serge Hallyn
Signed-off-by: Eric W. Biederman
23 Jul, 2012
3 commits
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It does not look like sysv FS needs 'write_super()' at all, because all it
does is a timestamp update. I cannot test this patch, because this
file-system is so old and probably has not been used by anyone for years,
so there are no tools to create it in Linux. But from the code I see that
marking the superblock as dirty is basically marking the superblock buffers as
drity and then setting the s_dirt flag. And when 'write_super()' is executed to
handle the s_dirt flag, we just update the timestamp and again mark the
superblock buffer as dirty. Seems pointless.It looks like we can update the timestamp more opprtunistically - on unmount
or remount of sync, and nothing should change.Thus, this patch removes 'sysv_write_super()' and 's_dirt'.
Signed-off-by: Artem Bityutskiy
Signed-off-by: Al Viro -
We do not need to call 'sysv_write_super()' from 'sysv_remount()',
because VFS has called 'sysv_sync_fs()' before calling '->remount()'.
So remove it. Remove also '(un)lock_super()' which obvioulsy is becoming
useless in this function.Signed-off-by: Artem Bityutskiy
Signed-off-by: Al Viro -
We do not need to call 'sysv_write_super()' from 'sysv_put_super()',
because VFS has called 'sysv_sync_fs()' before calling '->put_super()'.
So remove it.Signed-off-by: Artem Bityutskiy
Signed-off-by: Al Viro
14 Jul, 2012
2 commits
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boolean "does it have to be exclusive?" flag is passed instead;
Local filesystem should just ignore it - the object is guaranteed
not to be there yet.Signed-off-by: Al Viro
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Just the flags; only NFS cares even about that, but there are
legitimate uses for such argument. And getting rid of that
completely would require splitting ->lookup() into a couple
of methods (at least), so let's leave that alone for now...Signed-off-by: Al Viro
06 May, 2012
1 commit
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After we moved inode_sync_wait() from end_writeback() it doesn't make sense
to call the function end_writeback() anymore. Rename it to clear_inode()
which well says what the function really does - set I_CLEAR flag.Signed-off-by: Jan Kara
Signed-off-by: Fengguang Wu
21 Mar, 2012
2 commits
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Signed-off-by: Al Viro
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New field of struct super_block - ->s_max_links. Maximal allowed
value of ->i_nlink or 0; in the latter case all checks still need
to be done in ->link/->mkdir/->rename instances. Note that this
limit applies both to directoris and to non-directories.Signed-off-by: Al Viro
07 Jan, 2012
1 commit
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Signed-off-by: Al Viro
04 Jan, 2012
5 commits
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Signed-off-by: Al Viro
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Signed-off-by: Al Viro
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vfs_create() ignores everything outside of 16bit subset of its
mode argument; switching it to umode_t is obviously equivalent
and it's the only caller of the methodSigned-off-by: Al Viro
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vfs_mkdir() gets int, but immediately drops everything that might not
fit into umode_t and that's the only caller of ->mkdir()...Signed-off-by: Al Viro
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Seeing that just about every destructor got that INIT_LIST_HEAD() copied into
it, there is no point whatsoever keeping this INIT_LIST_HEAD in inode_init_once();
the cost of taking it into inode_init_always() will be negligible for pipes
and sockets and negative for everything else. Not to mention the removal of
boilerplate code from ->destroy_inode() instances...Signed-off-by: Al Viro
02 Nov, 2011
1 commit
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Replace remaining direct i_nlink updates with a new set_nlink()
updater function.Signed-off-by: Miklos Szeredi
Tested-by: Toshiyuki Okajima
Signed-off-by: Christoph Hellwig
28 May, 2011
1 commit
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sysv does not have problems with references to unlinked directories.
CC: Christoph Hellwig
Signed-off-by: Sage Weil
Signed-off-by: Al Viro
26 May, 2011
2 commits
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Only a few file systems need this. Start by pushing it down into each
rename method (except gfs2 and xfs) so that it can be dealt with on a
per-fs basis.Acked-by: Christoph Hellwig
Signed-off-by: Sage Weil
Signed-off-by: Al Viro -
Only a few file systems need this. Start by pushing it down into each
fs rmdir method (except gfs2 and xfs) so it can be dealt with on a per-fs
basis.This does not change behavior for any in-tree file systems.
Acked-by: Christoph Hellwig
Signed-off-by: Sage Weil
Signed-off-by: Al Viro
25 Mar, 2011
1 commit
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* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits)
Documentation/iostats.txt: bit-size reference etc.
cfq-iosched: removing unnecessary think time checking
cfq-iosched: Don't clear queue stats when preempt.
blk-throttle: Reset group slice when limits are changed
blk-cgroup: Only give unaccounted_time under debug
cfq-iosched: Don't set active queue in preempt
block: fix non-atomic access to genhd inflight structures
block: attempt to merge with existing requests on plug flush
block: NULL dereference on error path in __blkdev_get()
cfq-iosched: Don't update group weights when on service tree
fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away
block: Require subsystems to explicitly allocate bio_set integrity mempool
jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
fs: make fsync_buffers_list() plug
mm: make generic_writepages() use plugging
blk-cgroup: Add unaccounted time to timeslice_used.
block: fixup plugging stubs for !CONFIG_BLOCK
block: remove obsolete comments for blkdev_issue_zeroout.
blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.
...Fix up conflicts in fs/{aio.c,super.c}
10 Mar, 2011
1 commit
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Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().Signed-off-by: Jens Axboe
03 Mar, 2011
1 commit
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Signed-off-by: Al Viro
13 Jan, 2011
1 commit
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Signed-off-by: Al Viro
07 Jan, 2011
3 commits
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Reduce some branches and memory accesses in dcache lookup by adding dentry
flags to indicate common d_ops are set, rather than having to check them.
This saves a pointer memory access (dentry->d_op) in common path lookup
situations, and saves another pointer load and branch in cases where we
have d_op but not the particular operation.Patched with:
git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i
Signed-off-by: Nick Piggin
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RCU free the struct inode. This will allow:
- Subsequent store-free path walking patch. The inode must be consulted for
permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
to take i_lock no longer need to take sb_inode_list_lock to walk the list in
the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
page lock to follow page->mapping.The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.Signed-off-by: Nick Piggin
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Change d_hash so it may be called from lock-free RCU lookups. See similar
patch for d_compare for details.For in-tree filesystems, this is just a mechanical change.
Signed-off-by: Nick Piggin
29 Oct, 2010
1 commit
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... and switch of the obvious get_sb_bdev() users to ->mount()
Signed-off-by: Al Viro
26 Oct, 2010
1 commit
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Clones an existing reference to inode; caller must already hold one.
Signed-off-by: Al Viro
11 Aug, 2010
3 commits
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This adds byte order autodetection (of PDP-11 and LE filesystems). No
attempt is made to detect big-endian filesystems -- were there any?
Tested with PDP-11 v7 filesystems and PC-IX maintenance floppy.[akpm@linux-foundation.org: coding-style fixes]
[AV: parser.h inclusion was a rudiment of discarded stuff]
Signed-off-by: Lubomir Rintel
Cc: Christoph Hellwig
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Al Viro -
Newly mkfs-ed filesystems from Seventh Edition have last modification
time set to zero, but are otherwise perfectly valid.Also, tighten up other sanity checks to filter out most filesystems with
different bytesex than we're using.Cc: Christoph Hellwig
Signed-off-by: Lubomir Rintel
Signed-off-by: Al Viro -
So that the module gets autoloaded when a v7 filesystem is mounted.
Cc: Christoph Hellwig
Signed-off-by: Lubomir Rintel
Signed-off-by: Al Viro
