gcc 8.1.0 complains:
fs/kernfs/symlink.c:91:3: warning:
'strncpy' output truncated before terminating nul copying
as many bytes from a string as its length
fs/kernfs/symlink.c: In function 'kernfs_iop_get_link':
fs/kernfs/symlink.c:88:14: note: length computed here
Using strncpy() is indeed less than perfect since the length of data to
be copied has already been determined with strlen(). Replace strncpy()
with memcpy() to address the warning and optimize the code a little.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is a late set of changes from Deepa Dinamani doing an automated
treewide conversion of the inode and iattr structures from 'timespec'
to 'timespec64', to push the conversion from the VFS layer into the
individual file systems.
There were no conflicts between this and the contents of linux-next
until just before the merge window, when we saw multiple problems:
- A minor conflict with my own y2038 fixes, which I could address
by adding another patch on top here.
- One semantic conflict with late changes to the NFS tree. I addressed
this by merging Deepa's original branch on top of the changes that
now got merged into mainline and making sure the merge commit includes
the necessary changes as produced by coccinelle.
- A trivial conflict against the removal of staging/lustre.
- Multiple conflicts against the VFS changes in the overlayfs tree.
These are still part of linux-next, but apparently this is no longer
intended for 4.18 [1], so I am ignoring that part.
As Deepa writes:
The series aims to switch vfs timestamps to use struct timespec64.
Currently vfs uses struct timespec, which is not y2038 safe.
The series involves the following:
1. Add vfs helper functions for supporting struct timepec64 timestamps.
2. Cast prints of vfs timestamps to avoid warnings after the switch.
3. Simplify code using vfs timestamps so that the actual
replacement becomes easy.
4. Convert vfs timestamps to use struct timespec64 using a script.
This is a flag day patch.
Next steps:
1. Convert APIs that can handle timespec64, instead of converting
timestamps at the boundaries.
2. Update internal data structures to avoid timestamp conversions.
Thomas Gleixner adds:
I think there is no point to drag that out for the next merge window.
The whole thing needs to be done in one go for the core changes which
means that you're going to play that catchup game forever. Let's get
over with it towards the end of the merge window.
[1] https://www.spinics.net/lists/linux-fsdevel/msg128294.html
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Merge tag 'vfs-timespec64' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground
Pull inode timestamps conversion to timespec64 from Arnd Bergmann:
"This is a late set of changes from Deepa Dinamani doing an automated
treewide conversion of the inode and iattr structures from 'timespec'
to 'timespec64', to push the conversion from the VFS layer into the
individual file systems.
As Deepa writes:
'The series aims to switch vfs timestamps to use struct timespec64.
Currently vfs uses struct timespec, which is not y2038 safe.
The series involves the following:
1. Add vfs helper functions for supporting struct timepec64
timestamps.
2. Cast prints of vfs timestamps to avoid warnings after the switch.
3. Simplify code using vfs timestamps so that the actual replacement
becomes easy.
4. Convert vfs timestamps to use struct timespec64 using a script.
This is a flag day patch.
Next steps:
1. Convert APIs that can handle timespec64, instead of converting
timestamps at the boundaries.
2. Update internal data structures to avoid timestamp conversions'
Thomas Gleixner adds:
'I think there is no point to drag that out for the next merge
window. The whole thing needs to be done in one go for the core
changes which means that you're going to play that catchup game
forever. Let's get over with it towards the end of the merge window'"
* tag 'vfs-timespec64' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground:
pstore: Remove bogus format string definition
vfs: change inode times to use struct timespec64
pstore: Convert internal records to timespec64
udf: Simplify calls to udf_disk_stamp_to_time
fs: nfs: get rid of memcpys for inode times
ceph: make inode time prints to be long long
lustre: Use long long type to print inode time
fs: add timespec64_truncate()
Pull the timespec64 conversion from Deepa Dinamani:
"The series aims to switch vfs timestamps to use
struct timespec64. Currently vfs uses struct timespec,
which is not y2038 safe.
The flag patch applies cleanly. I've not seen the timestamps
update logic change often. The series applies cleanly on 4.17-rc6
and linux-next tip (top commit: next-20180517).
I'm not sure how to merge this kind of a series with a flag patch.
We are targeting 4.18 for this.
Let me know if you have other suggestions.
The series involves the following:
1. Add vfs helper functions for supporting struct timepec64 timestamps.
2. Cast prints of vfs timestamps to avoid warnings after the switch.
3. Simplify code using vfs timestamps so that the actual
replacement becomes easy.
4. Convert vfs timestamps to use struct timespec64 using a script.
This is a flag day patch.
I've tried to keep the conversions with the script simple, to
aid in the reviews. I've kept all the internal filesystem data
structures and function signatures the same.
Next steps:
1. Convert APIs that can handle timespec64, instead of converting
timestamps at the boundaries.
2. Update internal data structures to avoid timestamp conversions."
I've pulled it into a branch based on top of the NFS changes that
are now in mainline, so I could resolve the non-obvious conflict
between the two while merging.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Here is the driver core patchset for 4.18-rc1.
The large chunk of these are firmware core documentation and api
updates. Nothing major there, just better descriptions for others to be
able to understand the firmware code better. There's also a user for a
new firmware api call.
Other than that, there are some minor updates for debugfs, kernfs, and
the driver core itself.
All of these have been in linux-next for a while with no reported
issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here is the driver core patchset for 4.18-rc1.
The large chunk of these are firmware core documentation and api
updates. Nothing major there, just better descriptions for others to
be able to understand the firmware code better. There's also a user
for a new firmware api call.
Other than that, there are some minor updates for debugfs, kernfs, and
the driver core itself.
All of these have been in linux-next for a while with no reported
issues"
* tag 'driver-core-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (23 commits)
driver core: hold dev's parent lock when needed
driver-core: return EINVAL error instead of BUG_ON()
driver core: add __printf verification to device_create_groups_vargs
mm: memory_hotplug: use put_device() if device_register fail
base: core: fix typo 'can by' to 'can be'
debugfs: inode: debugfs_create_dir uses mode permission from parent
debugfs: Re-use kstrtobool_from_user()
Documentation: clarify firmware_class provenance and why we can't rename the module
Documentation: remove stale firmware API reference
Documentation: fix few typos and clarifications for the firmware loader
ath10k: re-enable the firmware fallback mechanism for testmode
ath10k: use firmware_request_nowarn() to load firmware
firmware: add firmware_request_nowarn() - load firmware without warnings
firmware_loader: make firmware_fallback_sysfs() print more useful
firmware_loader: move kconfig FW_LOADER entries to its own file
firmware_loader: replace ---help--- with help
firmware_loader: enhance Kconfig documentation over FW_LOADER
firmware_loader: document firmware_sysfs_fallback()
firmware: rename fw_sysfs_fallback to firmware_fallback_sysfs()
firmware: use () to terminate kernel-doc function names
...
Use new return type vm_fault_t for page_mkwrite and
fault handler. For now, this is just documenting that
the function returns a VM_FAULT value rather than an
errno. Once all instances are converted, vm_fault_t
will become a distinct type.
Reference id -> 1c8f422059 ("mm: change return type to
vm_fault_t")
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:
for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
done
with de-mangling cleanups yet to come.
NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do. But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.
The next patch from Al will sort out the final differences, and we
should be all done.
Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull misc vfs fixes from Al Viro.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
seq_file: fix incomplete reset on read from zero offset
kernfs: fix regression in kernfs_fop_write caused by wrong type
Pull poll annotations from Al Viro:
"This introduces a __bitwise type for POLL### bitmap, and propagates
the annotations through the tree. Most of that stuff is as simple as
'make ->poll() instances return __poll_t and do the same to local
variables used to hold the future return value'.
Some of the obvious brainos found in process are fixed (e.g. POLLIN
misspelled as POLL_IN). At that point the amount of sparse warnings is
low and most of them are for genuine bugs - e.g. ->poll() instance
deciding to return -EINVAL instead of a bitmap. I hadn't touched those
in this series - it's large enough as it is.
Another problem it has caught was eventpoll() ABI mess; select.c and
eventpoll.c assumed that corresponding POLL### and EPOLL### were
equal. That's true for some, but not all of them - EPOLL### are
arch-independent, but POLL### are not.
The last commit in this series separates userland POLL### values from
the (now arch-independent) kernel-side ones, converting between them
in the few places where they are copied to/from userland. AFAICS, this
is the least disruptive fix preserving poll(2) ABI and making epoll()
work on all architectures.
As it is, it's simply broken on sparc - try to give it EPOLLWRNORM and
it will trigger only on what would've triggered EPOLLWRBAND on other
architectures. EPOLLWRBAND and EPOLLRDHUP, OTOH, are never triggered
at all on sparc. With this patch they should work consistently on all
architectures"
* 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits)
make kernel-side POLL... arch-independent
eventpoll: no need to mask the result of epi_item_poll() again
eventpoll: constify struct epoll_event pointers
debugging printk in sg_poll() uses %x to print POLL... bitmap
annotate poll(2) guts
9p: untangle ->poll() mess
->si_band gets POLL... bitmap stored into a user-visible long field
ring_buffer_poll_wait() return value used as return value of ->poll()
the rest of drivers/*: annotate ->poll() instances
media: annotate ->poll() instances
fs: annotate ->poll() instances
ipc, kernel, mm: annotate ->poll() instances
net: annotate ->poll() instances
apparmor: annotate ->poll() instances
tomoyo: annotate ->poll() instances
sound: annotate ->poll() instances
acpi: annotate ->poll() instances
crypto: annotate ->poll() instances
block: annotate ->poll() instances
x86: annotate ->poll() instances
...
Commit b7ce40cff0 ("kernfs: cache atomic_write_len in
kernfs_open_file") changes type of local variable 'len' from ssize_t
to size_t. This change caused that the *ppos value is updated also
when the previous write callback failed.
Mentioned snippet:
...
len = ops->write(...); <- return value can be negative
...
if (len > 0) <- true here in this case
*ppos += len;
...
Fixes: b7ce40cff0 ("kernfs: cache atomic_write_len in kernfs_open_file")
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This is a pure automated search-and-replace of the internal kernel
superblock flags.
The s_flags are now called SB_*, with the names and the values for the
moment mirroring the MS_* flags that they're equivalent to.
Note how the MS_xyz flags are the ones passed to the mount system call,
while the SB_xyz flags are what we then use in sb->s_flags.
The script to do this was:
# places to look in; re security/*: it generally should *not* be
# touched (that stuff parses mount(2) arguments directly), but
# there are two places where we really deal with superblock flags.
FILES="drivers/mtd drivers/staging/lustre fs ipc mm \
include/linux/fs.h include/uapi/linux/bfs_fs.h \
security/apparmor/apparmorfs.c security/apparmor/include/lib.h"
# the list of MS_... constants
SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \
DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \
POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \
I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \
ACTIVE NOUSER"
SED_PROG=
for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done
# we want files that contain at least one of MS_...,
# with fs/namespace.c and fs/pnode.c excluded.
L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c')
for f in $L; do sed -i $f $SED_PROG; done
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull block layer updates from Jens Axboe:
"This is the first pull request for 4.14, containing most of the code
changes. It's a quiet series this round, which I think we needed after
the churn of the last few series. This contains:
- Fix for a registration race in loop, from Anton Volkov.
- Overflow complaint fix from Arnd for DAC960.
- Series of drbd changes from the usual suspects.
- Conversion of the stec/skd driver to blk-mq. From Bart.
- A few BFQ improvements/fixes from Paolo.
- CFQ improvement from Ritesh, allowing idling for group idle.
- A few fixes found by Dan's smatch, courtesy of Dan.
- A warning fixup for a race between changing the IO scheduler and
device remova. From David Jeffery.
- A few nbd fixes from Josef.
- Support for cgroup info in blktrace, from Shaohua.
- Also from Shaohua, new features in the null_blk driver to allow it
to actually hold data, among other things.
- Various corner cases and error handling fixes from Weiping Zhang.
- Improvements to the IO stats tracking for blk-mq from me. Can
drastically improve performance for fast devices and/or big
machines.
- Series from Christoph removing bi_bdev as being needed for IO
submission, in preparation for nvme multipathing code.
- Series from Bart, including various cleanups and fixes for switch
fall through case complaints"
* 'for-4.14/block' of git://git.kernel.dk/linux-block: (162 commits)
kernfs: checking for IS_ERR() instead of NULL
drbd: remove BIOSET_NEED_RESCUER flag from drbd_{md_,}io_bio_set
drbd: Fix allyesconfig build, fix recent commit
drbd: switch from kmalloc() to kmalloc_array()
drbd: abort drbd_start_resync if there is no connection
drbd: move global variables to drbd namespace and make some static
drbd: rename "usermode_helper" to "drbd_usermode_helper"
drbd: fix race between handshake and admin disconnect/down
drbd: fix potential deadlock when trying to detach during handshake
drbd: A single dot should be put into a sequence.
drbd: fix rmmod cleanup, remove _all_ debugfs entries
drbd: Use setup_timer() instead of init_timer() to simplify the code.
drbd: fix potential get_ldev/put_ldev refcount imbalance during attach
drbd: new disk-option disable-write-same
drbd: Fix resource role for newly created resources in events2
drbd: mark symbols static where possible
drbd: Send P_NEG_ACK upon write error in protocol != C
drbd: add explicit plugging when submitting batches
drbd: change list_for_each_safe to while(list_first_entry_or_null)
drbd: introduce drbd_recv_header_maybe_unplug
...
The reference count in kernfs_node structure is treated like a rwsem by
using lockdep instrumentation code. The lockdep name, however, is still
"s_active" which is carried over from the old sysfs code. As s_active
is no longer the variable name, its use may confuse users on where the
lock is when it is reported by lockdep. So it is changed to "kn->count"
which is how this variable is normally referenced in kernfs code.
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
By default we output cgroup id in blktrace. This adds an option to
display cgroup path. Since get cgroup path is a relativly heavy
operation, we don't enable it by default.
with the option enabled, blktrace will output something like this:
dd-1353 [007] d..2 293.015252: 8,0 /test/level D R 24 + 8 [dd]
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now we have the facilities to implement exportfs operations. The idea is
cgroup can export the fhandle info to userspace, then userspace uses
fhandle to find the cgroup name. Another example is userspace can get
fhandle for a cgroup and BPF uses the fhandle to filter info for the
cgroup.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
inode number and generation can identify a kernfs node. We are going to
export the identification by exportfs operations, so put ino and
generation into a separate structure. It's convenient when later patches
use the identification.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When working on adding exportfs operations in kernfs, I found it's hard
to initialize dentry->d_fsdata in the exportfs operations. Looks there
is no way to do it without race condition. Look at the kernfs code
closely, there is no point to set dentry->d_fsdata. inode->i_private
already points to kernfs_node, and we can get inode from a dentry. So
this patch just delete the d_fsdata usage.
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add an API to get kernfs node from inode number. We will need this to
implement exportfs operations.
This API will be used in blktrace too later, so it should be as fast as
possible. To make the API lock free, kernfs node is freed in RCU
context. And we depend on kernfs_node count/ino number to filter out
stale kernfs nodes.
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Set i_generation for kernfs inode. This is required to implement
exportfs operations. The generation is 32-bit, so it's possible the
generation wraps up and we find stale files. To reduce the posssibility,
we don't reuse inode numer immediately. When the inode number allocation
wraps, we increase generation number. In this way generation/inode
number consist of a 64-bit number which is unlikely duplicated. This
does make the idr tree more sparse and waste some memory. Since idr
manages 32-bit keys, idr uses a 6-level radix tree, each level covers 6
bits of the key. In a 100k inode kernfs, the worst case will have around
300k radix tree node. Each node is 576bytes, so the tree will use about
~150M memory. Sounds not too bad, if this really is a problem, we should
find better data structure.
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
kernfs uses ida to manage inode number. The problem is we can't get
kernfs_node from inode number with ida. Switching to use idr, next patch
will add an API to get kernfs_node from inode number.
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Recently started seeing a kernel oops when a module tries removing a
memory mapped sysfs bin_attribute. On closer investigation the root
cause seems to be kernfs_release_file() trying to call
kernfs_op.release() callback that's NULL for such sysfs
bin_attributes. The oops occurs when kernfs_release_file() is called from
kernfs_drain_open_files() to cleanup any open handles with active
memory mappings.
The patch fixes this by checking for flag KERNFS_HAS_RELEASE before
calling kernfs_release_file() in function kernfs_drain_open_files().
On ppc64-le arch with cxl module the oops back-trace is of the
form below:
[ 861.381126] Unable to handle kernel paging request for instruction fetch
[ 861.381360] Faulting instruction address: 0x00000000
[ 861.381428] Oops: Kernel access of bad area, sig: 11 [#1]
....
[ 861.382481] NIP: 0000000000000000 LR: c000000000362c60 CTR:
0000000000000000
....
Call Trace:
[c000000f1680b750] [c000000000362c34] kernfs_drain_open_files+0x104/0x1d0 (unreliable)
[c000000f1680b790] [c00000000035fa00] __kernfs_remove+0x260/0x2c0
[c000000f1680b820] [c000000000360da0] kernfs_remove_by_name_ns+0x60/0xe0
[c000000f1680b8b0] [c0000000003638f4] sysfs_remove_bin_file+0x24/0x40
[c000000f1680b8d0] [c00000000062a164] device_remove_bin_file+0x24/0x40
[c000000f1680b8f0] [d000000009b7b22c] cxl_sysfs_afu_remove+0x144/0x170 [cxl]
[c000000f1680b940] [d000000009b7c7e4] cxl_remove+0x6c/0x1a0 [cxl]
[c000000f1680b990] [c00000000052f694] pci_device_remove+0x64/0x110
[c000000f1680b9d0] [c0000000006321d4] device_release_driver_internal+0x1f4/0x2b0
[c000000f1680ba20] [c000000000525cb0] pci_stop_bus_device+0xa0/0xd0
[c000000f1680ba60] [c000000000525e80] pci_stop_and_remove_bus_device+0x20/0x40
[c000000f1680ba90] [c00000000004a6c4] pci_hp_remove_devices+0x84/0xc0
[c000000f1680bad0] [c00000000004a688] pci_hp_remove_devices+0x48/0xc0
[c000000f1680bb10] [c0000000009dfda4] eeh_reset_device+0xb0/0x290
[c000000f1680bbb0] [c000000000032b4c] eeh_handle_normal_event+0x47c/0x530
[c000000f1680bc60] [c000000000032e64] eeh_handle_event+0x174/0x350
[c000000f1680bd10] [c000000000033228] eeh_event_handler+0x1e8/0x1f0
[c000000f1680bdc0] [c0000000000d384c] kthread+0x14c/0x190
[c000000f1680be30] [c00000000000b5a0] ret_from_kernel_thread+0x5c/0xbc
Fixes: f83f3c5156 ("kernfs: fix locking around kernfs_ops->release() callback")
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull vfs 'statx()' update from Al Viro.
This adds the new extended stat() interface that internally subsumes our
previous stat interfaces, and allows user mode to specify in more detail
what kind of information it wants.
It also allows for some explicit synchronization information to be
passed to the filesystem, which can be relevant for network filesystems:
is the cached value ok, or do you need open/close consistency, or what?
From David Howells.
Andreas Dilger points out that the first version of the extended statx
interface was posted June 29, 2010:
https://www.spinics.net/lists/linux-fsdevel/msg33831.html
* 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
statx: Add a system call to make enhanced file info available
Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.
The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.
Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.
========
OVERVIEW
========
The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.
A number of requests were gathered for features to be included. The
following have been included:
(1) Make the fields a consistent size on all arches and make them large.
(2) Spare space, request flags and information flags are provided for
future expansion.
(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).
(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).
This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].
(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).
(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).
And the following have been left out for future extension:
(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].
Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.
(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).
(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].
(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].
(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).
(10) Extra coherency data may be useful in making backups [Andreas Dilger].
(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).
(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...
(This requires a separate system call - I have an fsinfo() call idea
for this).
(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].
(Deferred to fsinfo).
(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].
(Deferred to fsinfo).
(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).
(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).
(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].
(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).
(16) Femtosecond-resolution timestamps [Dave Chinner].
(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).
(17) A set multiple attributes syscall to go with this.
===============
NEW SYSTEM CALL
===============
The new system call is:
int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);
The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.
Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):
(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.
(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.
(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.
mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.
buffer points to the destination for the data. This must be 256 bytes in
size.
======================
MAIN ATTRIBUTES RECORD
======================
The following structures are defined in which to return the main attribute
set:
struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};
struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};
The defined bits in request_mask and stx_mask are:
STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]
stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.
Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.
The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:
STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs
Within the kernel, the supported flags are listed by:
KSTAT_ATTR_FS_IOC_FLAGS
[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]
New flags include:
STATX_ATTR_AUTOMOUNT Object is an automount trigger
These are for the use of GUI tools that might want to mark files specially,
depending on what they are.
Fields in struct statx come in a number of classes:
(0) stx_dev_*, stx_blksize.
These are local system information and are always available.
(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.
These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.
If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.
If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.
Note that there are instances where the type might not be valid, for
instance Windows reparse points.
(2) stx_rdev_*.
This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.
(3) stx_btime.
Similar to (1), except this will be set to 0 if it doesn't exist.
=======
TESTING
=======
The following test program can be used to test the statx system call:
samples/statx/test-statx.c
Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.
Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.
[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)
Secondly, the result of automounting on that directory.
[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Update code that relied on sched.h including various MM types for them.
This will allow us to remove the <linux/mm_types.h> include from <linux/sched.h>.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull cgroup updates from Tejun Heo:
"Several noteworthy changes.
- Parav's rdma controller is finally merged. It is very straight
forward and can limit the abosolute numbers of common rdma
constructs used by different cgroups.
- kernel/cgroup.c got too chubby and disorganized. Created
kernel/cgroup/ subdirectory and moved all cgroup related files
under kernel/ there and reorganized the core code. This hurts for
backporting patches but was long overdue.
- cgroup v2 process listing reimplemented so that it no longer
depends on allocating a buffer large enough to cache the entire
result to sort and uniq the output. v2 has always mangled the sort
order to ensure that users don't depend on the sorted output, so
this shouldn't surprise anybody. This makes the pid listing
functions use the same iterators that are used internally, which
have to have the same iterating capabilities anyway.
- perf cgroup filtering now works automatically on cgroup v2. This
patch was posted a long time ago but somehow fell through the
cracks.
- misc fixes asnd documentation updates"
* 'for-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (27 commits)
kernfs: fix locking around kernfs_ops->release() callback
cgroup: drop the matching uid requirement on migration for cgroup v2
cgroup, perf_event: make perf_event controller work on cgroup2 hierarchy
cgroup: misc cleanups
cgroup: call subsys->*attach() only for subsystems which are actually affected by migration
cgroup: track migration context in cgroup_mgctx
cgroup: cosmetic update to cgroup_taskset_add()
rdmacg: Fixed uninitialized current resource usage
cgroup: Add missing cgroup-v2 PID controller documentation.
rdmacg: Added documentation for rdmacg
IB/core: added support to use rdma cgroup controller
rdmacg: Added rdma cgroup controller
cgroup: fix a comment typo
cgroup: fix RCU related sparse warnings
cgroup: move namespace code to kernel/cgroup/namespace.c
cgroup: rename functions for consistency
cgroup: move v1 mount functions to kernel/cgroup/cgroup-v1.c
cgroup: separate out cgroup1_kf_syscall_ops
cgroup: refactor mount path and clearly distinguish v1 and v2 paths
cgroup: move cgroup v1 specific code to kernel/cgroup/cgroup-v1.c
...
->fault(), ->page_mkwrite(), and ->pfn_mkwrite() calls do not need to
take a vma and vmf parameter when the vma already resides in vmf.
Remove the vma parameter to simplify things.
[arnd@arndb.de: fix ARM build]
Link: http://lkml.kernel.org/r/20170125223558.1451224-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/148521301778.19116.10840599906674778980.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The release callback may be called from two places - file release
operation and kernfs open file draining. kernfs_open_file->mutex is
used to synchronize the two callsites. This unfortunately leads to
possible circular locking because of->mutex is used to protect the
usual kernfs operations which may use locking constructs which are
held while removing and thus draining kernfs files.
@of->mutex is for synchronizing concurrent kernfs access operations
and all we need here is synchronization between the releaes and drain
paths. As the drain path has to grab kernfs_open_file_mutex anyway,
let's use the mutex to synchronize the release operation instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-tested-by: Tony Lindgren <tony@atomide.com>
Fixes: 0e67db2f9f ("kernfs: add kernfs_ops->open/release() callbacks")
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Null kernfs nodes could be found at cgroups during construction.
It seems safer to handle these null pointers right in kernfs in
the same way as printf prints "(null)" for null pointer string.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add ->open/release() methods to kernfs_ops. ->open() is called when
the file is opened and ->release() when the file is either released or
severed. These callbacks can be used, for example, to manage
persistent caching objects over multiple seq_file iterations.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Acked-by: Zefan Li <lizefan@huawei.com>
More kernfs_open_file->mutex synchronized flags are planned to be
added. Convert ->mmapped to a bitfield in preparation.
While at it, make kernfs_fop_mmap() use "true" instead of "1" on
->mmapped.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Acked-by: Zefan Li <lizefan@huawei.com>
Pull partial readlink cleanups from Miklos Szeredi.
This is the uncontroversial part of the readlink cleanup patch-set that
simplifies the default readlink handling.
Miklos and Al are still discussing the rest of the series.
* git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
vfs: make generic_readlink() static
vfs: remove ".readlink = generic_readlink" assignments
vfs: default to generic_readlink()
vfs: replace calling i_op->readlink with vfs_readlink()
proc/self: use generic_readlink
ecryptfs: use vfs_get_link()
bad_inode: add missing i_op initializers
If .readlink == NULL implies generic_readlink().
Generated by:
to_del="\.readlink.*=.*generic_readlink"
for i in `git grep -l $to_del`; do sed -i "/$to_del"/d $i; done
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This was spotted by the 'sparse' static checker.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If you edit a kernfs backed file with vi(1), you see an ugly error
message when you write the file because vi tries to fsync(2) the
file after writing, which fails.
We have noop_fsync() for this, use it.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull cgroup updates from Tejun Heo:
- tracepoints for basic cgroup management operations added
- kernfs and cgroup path formatting functions updated to behave in the
style of strlcpy()
- non-critical bug fixes
* 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
blkcg: Unlock blkcg_pol_mutex only once when cpd == NULL
cgroup: fix error handling regressions in proc_cgroup_show() and cgroup_release_agent()
cpuset: fix error handling regression in proc_cpuset_show()
cgroup: add tracepoints for basic operations
cgroup: make cgroup_path() and friends behave in the style of strlcpy()
kernfs: remove kernfs_path_len()
kernfs: make kernfs_path*() behave in the style of strlcpy()
kernfs: add dummy implementation of kernfs_path_from_node()
Pull more vfs updates from Al Viro:
">rename2() work from Miklos + current_time() from Deepa"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: Replace current_fs_time() with current_time()
fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps
fs: Replace CURRENT_TIME with current_time() for inode timestamps
fs: proc: Delete inode time initializations in proc_alloc_inode()
vfs: Add current_time() api
vfs: add note about i_op->rename changes to porting
fs: rename "rename2" i_op to "rename"
vfs: remove unused i_op->rename
fs: make remaining filesystems use .rename2
libfs: support RENAME_NOREPLACE in simple_rename()
fs: support RENAME_NOREPLACE for local filesystems
ncpfs: fix unused variable warning
Pull vfs xattr updates from Al Viro:
"xattr stuff from Andreas
This completes the switch to xattr_handler ->get()/->set() from
->getxattr/->setxattr/->removexattr"
* 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vfs: Remove {get,set,remove}xattr inode operations
xattr: Stop calling {get,set,remove}xattr inode operations
vfs: Check for the IOP_XATTR flag in listxattr
xattr: Add __vfs_{get,set,remove}xattr helpers
libfs: Use IOP_XATTR flag for empty directory handling
vfs: Use IOP_XATTR flag for bad-inode handling
vfs: Add IOP_XATTR inode operations flag
vfs: Move xattr_resolve_name to the front of fs/xattr.c
ecryptfs: Switch to generic xattr handlers
sockfs: Get rid of getxattr iop
sockfs: getxattr: Fail with -EOPNOTSUPP for invalid attribute names
kernfs: Switch to generic xattr handlers
hfs: Switch to generic xattr handlers
jffs2: Remove jffs2_{get,set,remove}xattr macros
xattr: Remove unnecessary NULL attribute name check
These inode operations are no longer used; remove them.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
current_fs_time() uses struct super_block* as an argument.
As per Linus's suggestion, this is changed to take struct
inode* as a parameter instead. This is because the function
is primarily meant for vfs inode timestamps.
Also the function was renamed as per Arnd's suggestion.
Change all calls to current_fs_time() to use the new
current_time() function instead. current_fs_time() will be
deleted.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This is trivial to do:
- add flags argument to foo_rename()
- check if flags is zero
- assign foo_rename() to .rename2 instead of .rename
This doesn't mean it's impossible to support RENAME_NOREPLACE for these
filesystems, but it is not trivial, like for local filesystems.
RENAME_NOREPLACE must guarantee atomicity (i.e. it shouldn't be possible
for a file to be created on one host while it is overwritten by rename on
another host).
Filesystems converted:
9p, afs, ceph, coda, ecryptfs, kernfs, lustre, ncpfs, nfs, ocfs2, orangefs.
After this, we can get rid of the duplicate interfaces for rename.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: David Howells <dhowells@redhat.com> [AFS]
Acked-by: Mike Marshall <hubcap@omnibond.com>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jan Harkes <jaharkes@cs.cmu.edu>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Oleg Drokin <oleg.drokin@intel.com>
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Mark Fasheh <mfasheh@suse.com>
inode_change_ok() will be resposible for clearing capabilities and IMA
extended attributes and as such will need dentry. Give it as an argument
to inode_change_ok() instead of an inode. Also rename inode_change_ok()
to setattr_prepare() to better relect that it does also some
modifications in addition to checks.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
kernfs_notify_workfn() sends out file modified events for the
scheduled kernfs_nodes. Because the modifications aren't from
userland, it doesn't have the matching file struct at hand and can't
use fsnotify_modify(). Instead, it looked up the inode and then used
d_find_any_alias() to find the dentry and used fsnotify_parent() and
fsnotify() directly to generate notifications.
The assumption was that the relevant dentries would have been pinned
if there are listeners, which isn't true as inotify doesn't pin
dentries at all and watching the parent doesn't pin the child dentries
even for dnotify. This led to, for example, inotify watchers not
getting notifications if the system is under memory pressure and the
matching dentries got reclaimed. It can also be triggered through
/proc/sys/vm/drop_caches or a remount attempt which involves shrinking
dcache.
fsnotify_parent() only uses the dentry to access the parent inode,
which kernfs can do easily. Update kernfs_notify_workfn() so that it
uses fsnotify() directly for both the parent and target inodes without
going through d_find_any_alias(). While at it, supply the target file
name to fsnotify() from kernfs_node->name.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Evgeny Vereshchagin <evvers@ya.ru>
Fixes: d911d98748 ("kernfs: make kernfs_notify() trigger inotify events too")
Cc: John McCutchan <john@johnmccutchan.com>
Cc: Robert Love <rlove@rlove.org>
Cc: Eric Paris <eparis@parisplace.org>
Cc: stable@vger.kernel.org # v3.16+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It doesn't have any in-kernel user and the same result can be obtained
from kernfs_path(@kn, NULL, 0). Remove it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Serge Hallyn <serge.hallyn@ubuntu.com>
kernfs_path*() functions always return the length of the full path but
the path content is undefined if the length is larger than the
provided buffer. This makes its behavior different from strlcpy() and
requires error handling in all its users even when they don't care
about truncation. In addition, the implementation can actully be
simplified by making it behave properly in strlcpy() style.
* Update kernfs_path_from_node_locked() to always fill up the buffer
with path. If the buffer is not large enough, the output is
truncated and terminated.
* kernfs_path() no longer needs error handling. Make it a simple
inline wrapper around kernfs_path_from_node().
* sysfs_warn_dup()'s use of kernfs_path() doesn't need error handling.
Updated accordingly.
* cgroup_path()'s use of kernfs_path() updated to retain the old
behavior.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Pull userns vfs updates from Eric Biederman:
"This tree contains some very long awaited work on generalizing the
user namespace support for mounting filesystems to include filesystems
with a backing store. The real world target is fuse but the goal is
to update the vfs to allow any filesystem to be supported. This
patchset is based on a lot of code review and testing to approach that
goal.
While looking at what is needed to support the fuse filesystem it
became clear that there were things like xattrs for security modules
that needed special treatment. That the resolution of those concerns
would not be fuse specific. That sorting out these general issues
made most sense at the generic level, where the right people could be
drawn into the conversation, and the issues could be solved for
everyone.
At a high level what this patchset does a couple of simple things:
- Add a user namespace owner (s_user_ns) to struct super_block.
- Teach the vfs to handle filesystem uids and gids not mapping into
to kuids and kgids and being reported as INVALID_UID and
INVALID_GID in vfs data structures.
By assigning a user namespace owner filesystems that are mounted with
only user namespace privilege can be detected. This allows security
modules and the like to know which mounts may not be trusted. This
also allows the set of uids and gids that are communicated to the
filesystem to be capped at the set of kuids and kgids that are in the
owning user namespace of the filesystem.
One of the crazier corner casees this handles is the case of inodes
whose i_uid or i_gid are not mapped into the vfs. Most of the code
simply doesn't care but it is easy to confuse the inode writeback path
so no operation that could cause an inode write-back is permitted for
such inodes (aka only reads are allowed).
This set of changes starts out by cleaning up the code paths involved
in user namespace permirted mounts. Then when things are clean enough
adds code that cleanly sets s_user_ns. Then additional restrictions
are added that are possible now that the filesystem superblock
contains owner information.
These changes should not affect anyone in practice, but there are some
parts of these restrictions that are changes in behavior.
- Andy's restriction on suid executables that does not honor the
suid bit when the path is from another mount namespace (think
/proc/[pid]/fd/) or when the filesystem was mounted by a less
privileged user.
- The replacement of the user namespace implicit setting of MNT_NODEV
with implicitly setting SB_I_NODEV on the filesystem superblock
instead.
Using SB_I_NODEV is a stronger form that happens to make this state
user invisible. The user visibility can be managed but it caused
problems when it was introduced from applications reasonably
expecting mount flags to be what they were set to.
There is a little bit of work remaining before it is safe to support
mounting filesystems with backing store in user namespaces, beyond
what is in this set of changes.
- Verifying the mounter has permission to read/write the block device
during mount.
- Teaching the integrity modules IMA and EVM to handle filesystems
mounted with only user namespace root and to reduce trust in their
security xattrs accordingly.
- Capturing the mounters credentials and using that for permission
checks in d_automount and the like. (Given that overlayfs already
does this, and we need the work in d_automount it make sense to
generalize this case).
Furthermore there are a few changes that are on the wishlist:
- Get all filesystems supporting posix acls using the generic posix
acls so that posix_acl_fix_xattr_from_user and
posix_acl_fix_xattr_to_user may be removed. [Maintainability]
- Reducing the permission checks in places such as remount to allow
the superblock owner to perform them.
- Allowing the superblock owner to chown files with unmapped uids and
gids to something that is mapped so the files may be treated
normally.
I am not considering even obvious relaxations of permission checks
until it is clear there are no more corner cases that need to be
locked down and handled generically.
Many thanks to Seth Forshee who kept this code alive, and putting up
with me rewriting substantial portions of what he did to handle more
corner cases, and for his diligent testing and reviewing of my
changes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (30 commits)
fs: Call d_automount with the filesystems creds
fs: Update i_[ug]id_(read|write) to translate relative to s_user_ns
evm: Translate user/group ids relative to s_user_ns when computing HMAC
dquot: For now explicitly don't support filesystems outside of init_user_ns
quota: Handle quota data stored in s_user_ns in quota_setxquota
quota: Ensure qids map to the filesystem
vfs: Don't create inodes with a uid or gid unknown to the vfs
vfs: Don't modify inodes with a uid or gid unknown to the vfs
cred: Reject inodes with invalid ids in set_create_file_as()
fs: Check for invalid i_uid in may_follow_link()
vfs: Verify acls are valid within superblock's s_user_ns.
userns: Handle -1 in k[ug]id_has_mapping when !CONFIG_USER_NS
fs: Refuse uid/gid changes which don't map into s_user_ns
selinux: Add support for unprivileged mounts from user namespaces
Smack: Handle labels consistently in untrusted mounts
Smack: Add support for unprivileged mounts from user namespaces
fs: Treat foreign mounts as nosuid
fs: Limit file caps to the user namespace of the super block
userns: Remove the now unnecessary FS_USERNS_DEV_MOUNT flag
userns: Remove implicit MNT_NODEV fragility.
...
Introduce a function may_open_dev that tests MNT_NODEV and a new
superblock flab SB_I_NODEV. Use this new function in all of the
places where MNT_NODEV was previously tested.
Add the new SB_I_NODEV s_iflag to proc, sysfs, and mqueuefs as those
filesystems should never support device nodes, and a simple superblock
flags makes that very hard to get wrong. With SB_I_NODEV set if any
device nodes somehow manage to show up on on a filesystem those
device nodes will be unopenable.
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The cgroup filesystem is in the same boat as sysfs. No one ever
permits executables of any kind on the cgroup filesystem, and there is
no reasonable future case to support executables in the future.
Therefore move the setting of SB_I_NOEXEC which makes the code proof
against future mistakes of accidentally creating executables from
sysfs to kernfs itself. Making the code simpler and covering the
sysfs, cgroup, and cgroup2 filesystems.
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Start marking filesystems with a user namespace owner, s_user_ns. In
this change this is only used for permission checks of who may mount a
filesystem. Ultimately s_user_ns will be used for translating ids and
checking capabilities for filesystems mounted from user namespaces.
The default policy for setting s_user_ns is implemented in sget(),
which arranges for s_user_ns to be set to current_user_ns() and to
ensure that the mounter of the filesystem has CAP_SYS_ADMIN in that
user_ns.
The guts of sget are split out into another function sget_userns().
The function sget_userns calls alloc_super with the specified user
namespace or it verifies the existing superblock that was found
has the expected user namespace, and fails with EBUSY when it is not.
This failing prevents users with the wrong privileges mounting a
filesystem.
The reason for the split of sget_userns from sget is that in some
cases such as mount_ns and kernfs_mount_ns a different policy for
permission checking of mounts and setting s_user_ns is necessary, and
the existence of sget_userns() allows those policies to be
implemented.
The helper mount_ns is expected to be used for filesystems such as
proc and mqueuefs which present per namespace information. The
function mount_ns is modified to call sget_userns instead of sget to
ensure the user namespace owner of the namespace whose information is
presented by the filesystem is used on the superblock.
For sysfs and cgroup the appropriate permission checks are already in
place, and kernfs_mount_ns is modified to call sget_userns so that
the init_user_ns is the only user namespace used.
For the cgroup filesystem cgroup namespace mounts are bind mounts of a
subset of the full cgroup filesystem and as such s_user_ns must be the
same for all of them as there is only a single superblock.
Mounts of sysfs that vary based on the network namespace could in principle
change s_user_ns but it keeps the analysis and implementation of kernfs
simpler if that is not supported, and at present there appear to be no
benefits from supporting a different s_user_ns on any sysfs mount.
Getting the details of setting s_user_ns correct has been
a long process. Thanks to Pavel Tikhorirorv who spotted a leak
in sget_userns. Thanks to Seth Forshee who has kept the work alive.
Thanks-to: Seth Forshee <seth.forshee@canonical.com>
Thanks-to: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
We always mixed in the parent pointer into the dentry name hash, but we
did it late at lookup time. It turns out that we can simplify that
lookup-time action by salting the hash with the parent pointer early
instead of late.
A few other users of our string hashes also wanted to mix in their own
pointers into the hash, and those are updated to use the same mechanism.
Hash users that don't have any particular initial salt can just use the
NULL pointer as a no-salt.
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: George Spelvin <linux@sciencehorizons.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
smack ->d_instantiate() uses ->setxattr(), so to be able to call it before
we'd hashed the new dentry and attached it to inode, we need ->setxattr()
instances getting the inode as an explicit argument rather than obtaining
it from dentry.
Similar change for ->getxattr() had been done in commit ce23e64. Unlike
->getxattr() (which is used by both selinux and smack instances of
->d_instantiate()) ->setxattr() is used only by smack one and unfortunately
it got missed back then.
Reported-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Tested-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Here's the "big" driver core update for 4.7-rc1.
Mostly just debugfs changes, the long-known and messy races with removing
debugfs files should be fixed thanks to the great work of Nicolai Stange. We
also have some isa updates in here (the x86 maintainers told me to take it
through this tree), a new warning when we run out of dynamic char major
numbers, and a few other assorted changes, details in the shortlog.
All have been in linux-next for some time with no reported issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here's the "big" driver core update for 4.7-rc1.
Mostly just debugfs changes, the long-known and messy races with
removing debugfs files should be fixed thanks to the great work of
Nicolai Stange. We also have some isa updates in here (the x86
maintainers told me to take it through this tree), a new warning when
we run out of dynamic char major numbers, and a few other assorted
changes, details in the shortlog.
All have been in linux-next for some time with no reported issues"
* tag 'driver-core-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (32 commits)
Revert "base: dd: don't remove driver_data in -EPROBE_DEFER case"
gpio: ws16c48: Utilize the ISA bus driver
gpio: 104-idio-16: Utilize the ISA bus driver
gpio: 104-idi-48: Utilize the ISA bus driver
gpio: 104-dio-48e: Utilize the ISA bus driver
watchdog: ebc-c384_wdt: Utilize the ISA bus driver
iio: stx104: Utilize the module_isa_driver and max_num_isa_dev macros
iio: stx104: Add X86 dependency to STX104 Kconfig option
Documentation: Add ISA bus driver documentation
isa: Implement the max_num_isa_dev macro
isa: Implement the module_isa_driver macro
pnp: pnpbios: Add explicit X86_32 dependency to PNPBIOS
isa: Decouple X86_32 dependency from the ISA Kconfig option
driver-core: use 'dev' argument in dev_dbg_ratelimited stub
base: dd: don't remove driver_data in -EPROBE_DEFER case
kernfs: Move faulting copy_user operations outside of the mutex
devcoredump: add scatterlist support
debugfs: unproxify files created through debugfs_create_u32_array()
debugfs: unproxify files created through debugfs_create_blob()
debugfs: unproxify files created through debugfs_create_bool()
...
Pull parallel filesystem directory handling update from Al Viro.
This is the main parallel directory work by Al that makes the vfs layer
able to do lookup and readdir in parallel within a single directory.
That's a big change, since this used to be all protected by the
directory inode mutex.
The inode mutex is replaced by an rwsem, and serialization of lookups of
a single name is done by a "in-progress" dentry marker.
The series begins with xattr cleanups, and then ends with switching
filesystems over to actually doing the readdir in parallel (switching to
the "iterate_shared()" that only takes the read lock).
A more detailed explanation of the process from Al Viro:
"The xattr work starts with some acl fixes, then switches ->getxattr to
passing inode and dentry separately. This is the point where the
things start to get tricky - that got merged into the very beginning
of the -rc3-based #work.lookups, to allow untangling the
security_d_instantiate() mess. The xattr work itself proceeds to
switch a lot of filesystems to generic_...xattr(); no complications
there.
After that initial xattr work, the series then does the following:
- untangle security_d_instantiate()
- convert a bunch of open-coded lookup_one_len_unlocked() to calls of
that thing; one such place (in overlayfs) actually yields a trivial
conflict with overlayfs fixes later in the cycle - overlayfs ended
up switching to a variant of lookup_one_len_unlocked() sans the
permission checks. I would've dropped that commit (it gets
overridden on merge from #ovl-fixes in #for-next; proper resolution
is to use the variant in mainline fs/overlayfs/super.c), but I
didn't want to rebase the damn thing - it was fairly late in the
cycle...
- some filesystems had managed to depend on lookup/lookup exclusion
for *fs-internal* data structures in a way that would break if we
relaxed the VFS exclusion. Fixing hadn't been hard, fortunately.
- core of that series - parallel lookup machinery, replacing
->i_mutex with rwsem, making lookup_slow() take it only shared. At
that point lookups happen in parallel; lookups on the same name
wait for the in-progress one to be done with that dentry.
Surprisingly little code, at that - almost all of it is in
fs/dcache.c, with fs/namei.c changes limited to lookup_slow() -
making it use the new primitive and actually switching to locking
shared.
- parallel readdir stuff - first of all, we provide the exclusion on
per-struct file basis, same as we do for read() vs lseek() for
regular files. That takes care of most of the needed exclusion in
readdir/readdir; however, these guys are trickier than lookups, so
I went for switching them one-by-one. To do that, a new method
'->iterate_shared()' is added and filesystems are switched to it
as they are either confirmed to be OK with shared lock on directory
or fixed to be OK with that. I hope to kill the original method
come next cycle (almost all in-tree filesystems are switched
already), but it's still not quite finished.
- several filesystems get switched to parallel readdir. The
interesting part here is dealing with dcache preseeding by readdir;
that needs minor adjustment to be safe with directory locked only
shared.
Most of the filesystems doing that got switched to in those
commits. Important exception: NFS. Turns out that NFS folks, with
their, er, insistence on VFS getting the fuck out of the way of the
Smart Filesystem Code That Knows How And What To Lock(tm) have
grown the locking of their own. They had their own homegrown
rwsem, with lookup/readdir/atomic_open being *writers* (sillyunlink
is the reader there). Of course, with VFS getting the fuck out of
the way, as requested, the actual smarts of the smart filesystem
code etc. had become exposed...
- do_last/lookup_open/atomic_open cleanups. As the result, open()
without O_CREAT locks the directory only shared. Including the
->atomic_open() case. Backmerge from #for-linus in the middle of
that - atomic_open() fix got brought in.
- then comes NFS switch to saner (VFS-based ;-) locking, killing the
homegrown "lookup and readdir are writers" kinda-sorta rwsem. All
exclusion for sillyunlink/lookup is done by the parallel lookups
mechanism. Exclusion between sillyunlink and rmdir is a real rwsem
now - rmdir being the writer.
Result: NFS lookups/readdirs/O_CREAT-less opens happen in parallel
now.
- the rest of the series consists of switching a lot of filesystems
to parallel readdir; in a lot of cases ->llseek() gets simplified
as well. One backmerge in there (again, #for-linus - rockridge
fix)"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (74 commits)
ext4: switch to ->iterate_shared()
hfs: switch to ->iterate_shared()
hfsplus: switch to ->iterate_shared()
hostfs: switch to ->iterate_shared()
hpfs: switch to ->iterate_shared()
hpfs: handle allocation failures in hpfs_add_pos()
gfs2: switch to ->iterate_shared()
f2fs: switch to ->iterate_shared()
afs: switch to ->iterate_shared()
befs: switch to ->iterate_shared()
befs: constify stuff a bit
isofs: switch to ->iterate_shared()
get_acorn_filename(): deobfuscate a bit
btrfs: switch to ->iterate_shared()
logfs: no need to lock directory in lseek
switch ecryptfs to ->iterate_shared
9p: switch to ->iterate_shared()
fat: switch to ->iterate_shared()
romfs, squashfs: switch to ->iterate_shared()
more trivial ->iterate_shared conversions
...
Our caller expects 0 on success, not >0.
This fixes a bug in the patch
cgroup, kernfs: make mountinfo show properly scoped path for cgroup namespaces
where /sys does not show up in mountinfo, breaking criu.
Thanks for catching this, Andrei.
Reported-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Patch summary:
When showing a cgroupfs entry in mountinfo, show the path of the mount
root dentry relative to the reader's cgroup namespace root.
Short explanation (courtesy of mkerrisk):
If we create a new cgroup namespace, then we want both /proc/self/cgroup
and /proc/self/mountinfo to show cgroup paths that are correctly
virtualized with respect to the cgroup mount point. Previous to this
patch, /proc/self/cgroup shows the right info, but /proc/self/mountinfo
does not.
Long version:
When a uid 0 task which is in freezer cgroup /a/b, unshares a new cgroup
namespace, and then mounts a new instance of the freezer cgroup, the new
mount will be rooted at /a/b. The root dentry field of the mountinfo
entry will show '/a/b'.
cat > /tmp/do1 << EOF
mount -t cgroup -o freezer freezer /mnt
grep freezer /proc/self/mountinfo
EOF
unshare -Gm bash /tmp/do1
> 330 160 0:34 / /sys/fs/cgroup/freezer rw,nosuid,nodev,noexec,relatime - cgroup cgroup rw,freezer
> 355 133 0:34 /a/b /mnt rw,relatime - cgroup freezer rw,freezer
The task's freezer cgroup entry in /proc/self/cgroup will simply show
'/':
grep freezer /proc/self/cgroup
9:freezer:/
If instead the same task simply bind mounts the /a/b cgroup directory,
the resulting mountinfo entry will again show /a/b for the dentry root.
However in this case the task will find its own cgroup at /mnt/a/b,
not at /mnt:
mount --bind /sys/fs/cgroup/freezer/a/b /mnt
130 25 0:34 /a/b /mnt rw,nosuid,nodev,noexec,relatime shared:21 - cgroup cgroup rw,freezer
In other words, there is no way for the task to know, based on what is
in mountinfo, which cgroup directory is its own.
Example (by mkerrisk):
First, a little script to save some typing and verbiage:
echo -e "\t/proc/self/cgroup:\t$(cat /proc/self/cgroup | grep freezer)"
cat /proc/self/mountinfo | grep freezer |
awk '{print "\tmountinfo:\t\t" $4 "\t" $5}'
Create cgroup, place this shell into the cgroup, and look at the state
of the /proc files:
2653
2653 # Our shell
14254 # cat(1)
/proc/self/cgroup: 10:freezer:/a/b
mountinfo: / /sys/fs/cgroup/freezer
Create a shell in new cgroup and mount namespaces. The act of creating
a new cgroup namespace causes the process's current cgroups directories
to become its cgroup root directories. (Here, I'm using my own version
of the "unshare" utility, which takes the same options as the util-linux
version):
Look at the state of the /proc files:
/proc/self/cgroup: 10:freezer:/
mountinfo: / /sys/fs/cgroup/freezer
The third entry in /proc/self/cgroup (the pathname of the cgroup inside
the hierarchy) is correctly virtualized w.r.t. the cgroup namespace, which
is rooted at /a/b in the outer namespace.
However, the info in /proc/self/mountinfo is not for this cgroup
namespace, since we are seeing a duplicate of the mount from the
old mount namespace, and the info there does not correspond to the
new cgroup namespace. However, trying to create a new mount still
doesn't show us the right information in mountinfo:
# propagating to other mountns
/proc/self/cgroup: 7:freezer:/
mountinfo: /a/b /mnt/freezer
The act of creating a new cgroup namespace caused the process's
current freezer directory, "/a/b", to become its cgroup freezer root
directory. In other words, the pathname directory of the directory
within the newly mounted cgroup filesystem should be "/",
but mountinfo wrongly shows us "/a/b". The consequence of this is
that the process in the cgroup namespace cannot correctly construct
the pathname of its cgroup root directory from the information in
/proc/PID/mountinfo.
With this patch, the dentry root field in mountinfo is shown relative
to the reader's cgroup namespace. So the same steps as above:
/proc/self/cgroup: 10:freezer:/a/b
mountinfo: / /sys/fs/cgroup/freezer
/proc/self/cgroup: 10:freezer:/
mountinfo: /../.. /sys/fs/cgroup/freezer
/proc/self/cgroup: 10:freezer:/
mountinfo: / /mnt/freezer
cgroup.clone_children freezer.parent_freezing freezer.state tasks
cgroup.procs freezer.self_freezing notify_on_release
3164
2653 # First shell that placed in this cgroup
3164 # Shell started by 'unshare'
14197 # cat(1)
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Tested-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We've calculated @len to be the bytes we need for '/..' entries from
@kn_from to the common ancestor, and calculated @nlen to be the extra
bytes we need to get from the common ancestor to @kn_to. We use them
as such at the end. But in the loop copying the actual entries, we
overwrite @nlen. Use a temporary variable for that instead.
Without this, the return length, when the buffer is large enough, is
wrong. (When the buffer is NULL or too small, the returned value is
correct. The buffer contents are also correct.)
Interestingly, no callers of this function are affected by this as of
yet. However the upcoming cgroup_show_path() will be.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.
This promise never materialized. And unlikely will.
We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE. And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.
Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.
Let's stop pretending that pages in page cache are special. They are
not.
The changes are pretty straight-forward:
- <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};
- page_cache_get() -> get_page();
- page_cache_release() -> put_page();
This patch contains automated changes generated with coccinelle using
script below. For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.
The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.
There are few places in the code where coccinelle didn't reach. I'll
fix them manually in a separate patch. Comments and documentation also
will be addressed with the separate patch.
virtual patch
@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E
@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E
@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT
@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE
@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK
@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)
@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)
@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is in preparation for the series that transitions
filesystem timestamps to use 64 bit time and hence make
them y2038 safe.
CURRENT_TIME macro will be deleted before merging the
aforementioned series.
Use current_fs_time() instead of CURRENT_TIME for inode
timestamps.
struct kernfs_node is associated with a sysfs file/ directory.
Truncate the values to appropriate time granularity when
writing to inode timestamps of the files.
ktime_get_real_ts() is used to obtain times for
struct kernfs_iattrs. Since these times are later assigned to
inode times using timespec_truncate() for all filesystem based
operations, we can save the supers list traversal time here by
using ktime_get_real_ts() directly.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull cgroup namespace support from Tejun Heo:
"These are changes to implement namespace support for cgroup which has
been pending for quite some time now. It is very straight-forward and
only affects what part of cgroup hierarchies are visible.
After unsharing, mounting a cgroup fs will be scoped to the cgroups
the task belonged to at the time of unsharing and the cgroup paths
exposed to userland would be adjusted accordingly"
* 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: fix and restructure error handling in copy_cgroup_ns()
cgroup: fix alloc_cgroup_ns() error handling in copy_cgroup_ns()
Add FS_USERNS_FLAG to cgroup fs
cgroup: Add documentation for cgroup namespaces
cgroup: mount cgroupns-root when inside non-init cgroupns
kernfs: define kernfs_node_dentry
cgroup: cgroup namespace setns support
cgroup: introduce cgroup namespaces
sched: new clone flag CLONE_NEWCGROUP for cgroup namespace
kernfs: Add API to generate relative kernfs path
Add a new kernfs api is added to lookup the dentry for a particular
kernfs path.
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
The new function kernfs_path_from_node() generates and returns kernfs
path of a given kernfs_node relative to a given parent kernfs_node.
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
kernfs_walk_ns() uses a static path_buf[PATH_MAX] to separate out path
components. Keeping around the 4k buffer just for kernfs_walk_ns() is
wasteful. This patch makes it piggyback on kernfs_pr_cont_buf[]
instead. This requires kernfs_walk_ns() to hold kernfs_rename_lock.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).
Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Currently, all kmem allocations (namely every kmem_cache_alloc, kmalloc,
alloc_kmem_pages call) are accounted to memory cgroup automatically.
Callers have to explicitly opt out if they don't want/need accounting
for some reason. Such a design decision leads to several problems:
- kmalloc users are highly sensitive to failures, many of them
implicitly rely on the fact that kmalloc never fails, while memcg
makes failures quite plausible.
- A lot of objects are shared among different containers by design.
Accounting such objects to one of containers is just unfair.
Moreover, it might lead to pinning a dead memcg along with its kmem
caches, which aren't tiny, which might result in noticeable increase
in memory consumption for no apparent reason in the long run.
- There are tons of short-lived objects. Accounting them to memcg will
only result in slight noise and won't change the overall picture, but
we still have to pay accounting overhead.
For more info, see
- http://lkml.kernel.org/r/20151105144002.GB15111%40dhcp22.suse.cz
- http://lkml.kernel.org/r/20151106090555.GK29259@esperanza
Therefore this patchset switches to the white list policy. Now kmalloc
users have to explicitly opt in by passing __GFP_ACCOUNT flag.
Currently, the list of accounted objects is quite limited and only
includes those allocations that (1) are known to be easily triggered
from userspace and (2) can fail gracefully (for the full list see patch
no. 6) and it still misses many object types. However, accounting only
those objects should be a satisfactory approximation of the behavior we
used to have for most sane workloads.
This patch (of 6):
Revert 499611ed45 ("kernfs: do not account ino_ida allocations
to memcg").
Black-list kmem accounting policy (aka __GFP_NOACCOUNT) turned out to be
fragile and difficult to maintain, because there seem to be many more
allocations that should not be accounted than those that should be.
Besides, false accounting an allocation might result in much worse
consequences than not accounting at all, namely increased memory
consumption due to pinned dead kmem caches.
So it was decided to switch to the white-list policy. This patch reverts
bits introducing the black-list policy. The white-list policy will be
introduced later in the series.
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull networking updates from Davic Miller:
1) Support busy polling generically, for all NAPI drivers. From Eric
Dumazet.
2) Add byte/packet counter support to nft_ct, from Floriani Westphal.
3) Add RSS/XPS support to mvneta driver, from Gregory Clement.
4) Implement IPV6_HDRINCL socket option for raw sockets, from Hannes
Frederic Sowa.
5) Add support for T6 adapter to cxgb4 driver, from Hariprasad Shenai.
6) Add support for VLAN device bridging to mlxsw switch driver, from
Ido Schimmel.
7) Add driver for Netronome NFP4000/NFP6000, from Jakub Kicinski.
8) Provide hwmon interface to mlxsw switch driver, from Jiri Pirko.
9) Reorganize wireless drivers into per-vendor directories just like we
do for ethernet drivers. From Kalle Valo.
10) Provide a way for administrators "destroy" connected sockets via the
SOCK_DESTROY socket netlink diag operation. From Lorenzo Colitti.
11) Add support to add/remove multicast routes via netlink, from Nikolay
Aleksandrov.
12) Make TCP keepalive settings per-namespace, from Nikolay Borisov.
13) Add forwarding and packet duplication facilities to nf_tables, from
Pablo Neira Ayuso.
14) Dead route support in MPLS, from Roopa Prabhu.
15) TSO support for thunderx chips, from Sunil Goutham.
16) Add driver for IBM's System i/p VNIC protocol, from Thomas Falcon.
17) Rationalize, consolidate, and more completely document the checksum
offloading facilities in the networking stack. From Tom Herbert.
18) Support aborting an ongoing scan in mac80211/cfg80211, from
Vidyullatha Kanchanapally.
19) Use per-bucket spinlock for bpf hash facility, from Tom Leiming.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1375 commits)
net: bnxt: always return values from _bnxt_get_max_rings
net: bpf: reject invalid shifts
phonet: properly unshare skbs in phonet_rcv()
dwc_eth_qos: Fix dma address for multi-fragment skbs
phy: remove an unneeded condition
mdio: remove an unneed condition
mdio_bus: NULL dereference on allocation error
net: Fix typo in netdev_intersect_features
net: freescale: mac-fec: Fix build error from phy_device API change
net: freescale: ucc_geth: Fix build error from phy_device API change
bonding: Prevent IPv6 link local address on enslaved devices
IB/mlx5: Add flow steering support
net/mlx5_core: Export flow steering API
net/mlx5_core: Make ipv4/ipv6 location more clear
net/mlx5_core: Enable flow steering support for the IB driver
net/mlx5_core: Initialize namespaces only when supported by device
net/mlx5_core: Set priority attributes
net/mlx5_core: Connect flow tables
net/mlx5_core: Introduce modify flow table command
net/mlx5_core: Managing root flow table
...
Pull vfs xattr updates from Al Viro:
"Andreas' xattr cleanup series.
It's a followup to his xattr work that went in last cycle; -0.5KLoC"
* 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
xattr handlers: Simplify list operation
ocfs2: Replace list xattr handler operations
nfs: Move call to security_inode_listsecurity into nfs_listxattr
xfs: Change how listxattr generates synthetic attributes
tmpfs: listxattr should include POSIX ACL xattrs
tmpfs: Use xattr handler infrastructure
btrfs: Use xattr handler infrastructure
vfs: Distinguish between full xattr names and proper prefixes
posix acls: Remove duplicate xattr name definitions
gfs2: Remove gfs2_xattr_acl_chmod
vfs: Remove vfs_xattr_cmp
new method: ->get_link(); replacement of ->follow_link(). The differences
are:
* inode and dentry are passed separately
* might be called both in RCU and non-RCU mode;
the former is indicated by passing it a NULL dentry.
* when called that way it isn't allowed to block
and should return ERR_PTR(-ECHILD) if it needs to be called
in non-RCU mode.
It's a flagday change - the old method is gone, all in-tree instances
converted. Conversion isn't hard; said that, so far very few instances
do not immediately bail out when called in RCU mode. That'll change
in the next commits.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When a file on tmpfs has an ACL or a Default ACL, listxattr should include the
corresponding xattr name.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Use the VFS xattr handler infrastructure and get rid of similar code in
the filesystem. For implementing shmem_xattr_handler_set, we need a
version of simple_xattr_set which removes the attribute when value is
NULL. Use this to implement kernfs_iop_removexattr as well.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Implement kernfs_walk_and_get() which is similar to
kernfs_find_and_get() but can walk a path instead of just a name.
v2: Use strlcpy() instead of strlen() + memcpy() as suggested by
David.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: David Miller <davem@davemloft.net>
Add a function to determine the path length of a kernfs node. This
for now will be used by writeback tracepoint updates.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull user namespace updates from Eric Biederman:
"Long ago and far away when user namespaces where young it was realized
that allowing fresh mounts of proc and sysfs with only user namespace
permissions could violate the basic rule that only root gets to decide
if proc or sysfs should be mounted at all.
Some hacks were put in place to reduce the worst of the damage could
be done, and the common sense rule was adopted that fresh mounts of
proc and sysfs should allow no more than bind mounts of proc and
sysfs. Unfortunately that rule has not been fully enforced.
There are two kinds of gaps in that enforcement. Only filesystems
mounted on empty directories of proc and sysfs should be ignored but
the test for empty directories was insufficient. So in my tree
directories on proc, sysctl and sysfs that will always be empty are
created specially. Every other technique is imperfect as an ordinary
directory can have entries added even after a readdir returns and
shows that the directory is empty. Special creation of directories
for mount points makes the code in the kernel a smidge clearer about
it's purpose. I asked container developers from the various container
projects to help test this and no holes were found in the set of mount
points on proc and sysfs that are created specially.
This set of changes also starts enforcing the mount flags of fresh
mounts of proc and sysfs are consistent with the existing mount of
proc and sysfs. I expected this to be the boring part of the work but
unfortunately unprivileged userspace winds up mounting fresh copies of
proc and sysfs with noexec and nosuid clear when root set those flags
on the previous mount of proc and sysfs. So for now only the atime,
read-only and nodev attributes which userspace happens to keep
consistent are enforced. Dealing with the noexec and nosuid
attributes remains for another time.
This set of changes also addresses an issue with how open file
descriptors from /proc/<pid>/ns/* are displayed. Recently readlink of
/proc/<pid>/fd has been triggering a WARN_ON that has not been
meaningful since it was added (as all of the code in the kernel was
converted) and is not now actively wrong.
There is also a short list of issues that have not been fixed yet that
I will mention briefly.
It is possible to rename a directory from below to above a bind mount.
At which point any directory pointers below the renamed directory can
be walked up to the root directory of the filesystem. With user
namespaces enabled a bind mount of the bind mount can be created
allowing the user to pick a directory whose children they can rename
to outside of the bind mount. This is challenging to fix and doubly
so because all obvious solutions must touch code that is in the
performance part of pathname resolution.
As mentioned above there is also a question of how to ensure that
developers by accident or with purpose do not introduce exectuable
files on sysfs and proc and in doing so introduce security regressions
in the current userspace that will not be immediately obvious and as
such are likely to require breaking userspace in painful ways once
they are recognized"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
vfs: Remove incorrect debugging WARN in prepend_path
mnt: Update fs_fully_visible to test for permanently empty directories
sysfs: Create mountpoints with sysfs_create_mount_point
sysfs: Add support for permanently empty directories to serve as mount points.
kernfs: Add support for always empty directories.
proc: Allow creating permanently empty directories that serve as mount points
sysctl: Allow creating permanently empty directories that serve as mountpoints.
fs: Add helper functions for permanently empty directories.
vfs: Ignore unlocked mounts in fs_fully_visible
mnt: Modify fs_fully_visible to deal with locked ro nodev and atime
mnt: Refactor the logic for mounting sysfs and proc in a user namespace
Add a new function kernfs_create_empty_dir that can be used to create
directory that can not be modified.
Update the code to use make_empty_dir_inode when reporting a
permanently empty directory to the vfs.
Update the code to not allow adding to permanently empty directories.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull cgroup updates from Tejun Heo:
- threadgroup_lock got reorganized so that its users can pick the
actual locking mechanism to use. Its only user - cgroups - is
updated to use a percpu_rwsem instead of per-process rwsem.
This makes things a bit lighter on hot paths and allows cgroups to
perform and fail multi-task (a process) migrations atomically.
Multi-task migrations are used in several places including the
unified hierarchy.
- Delegation rule and documentation added to unified hierarchy. This
will likely be the last interface update from the cgroup core side
for unified hierarchy before lifting the devel mask.
- Some groundwork for the pids controller which is scheduled to be
merged in the coming devel cycle.
* 'for-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: add delegation section to unified hierarchy documentation
cgroup: require write perm on common ancestor when moving processes on the default hierarchy
cgroup: separate out cgroup_procs_write_permission() from __cgroup_procs_write()
kernfs: make kernfs_get_inode() public
MAINTAINERS: add a cgroup core co-maintainer
cgroup: fix uninitialised iterator in for_each_subsys_which
cgroup: replace explicit ss_mask checking with for_each_subsys_which
cgroup: use bitmask to filter for_each_subsys
cgroup: add seq_file forward declaration for struct cftype
cgroup: simplify threadgroup locking
sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsem
sched, cgroup: reorganize threadgroup locking
cgroup: switch to unsigned long for bitmasks
cgroup: reorganize include/linux/cgroup.h
cgroup: separate out include/linux/cgroup-defs.h
cgroup: fix some comment typos
Here is the driver core / firmware changes for 4.2-rc1.
A number of small changes all over the place in the driver core, and in
the firmware subsystem. Nothing really major, full details in the
shortlog. Some of it is a bit of churn, given that the platform driver
probing changes was found to not work well, so they were reverted.
All of these have been in linux-next for a while with no reported
issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here is the driver core / firmware changes for 4.2-rc1.
A number of small changes all over the place in the driver core, and
in the firmware subsystem. Nothing really major, full details in the
shortlog. Some of it is a bit of churn, given that the platform
driver probing changes was found to not work well, so they were
reverted.
All of these have been in linux-next for a while with no reported
issues"
* tag 'driver-core-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (31 commits)
Revert "base/platform: Only insert MEM and IO resources"
Revert "base/platform: Continue on insert_resource() error"
Revert "of/platform: Use platform_device interface"
Revert "base/platform: Remove code duplication"
firmware: add missing kfree for work on async call
fs: sysfs: don't pass count == 0 to bin file readers
base:dd - Fix for typo in comment to function driver_deferred_probe_trigger().
base/platform: Remove code duplication
of/platform: Use platform_device interface
base/platform: Continue on insert_resource() error
base/platform: Only insert MEM and IO resources
firmware: use const for remaining firmware names
firmware: fix possible use after free on name on asynchronous request
firmware: check for file truncation on direct firmware loading
firmware: fix __getname() missing failure check
drivers: of/base: move of_init to driver_init
drivers/base: cacheinfo: fix annoying typo when DT nodes are absent
sysfs: disambiguate between "error code" and "failure" in comments
driver-core: fix build for !CONFIG_MODULES
driver-core: make __device_attach() static
...
Pull vfs updates from Al Viro:
"In this pile: pathname resolution rewrite.
- recursion in link_path_walk() is gone.
- nesting limits on symlinks are gone (the only limit remaining is
that the total amount of symlinks is no more than 40, no matter how
nested).
- "fast" (inline) symlinks are handled without leaving rcuwalk mode.
- stack footprint (independent of the nesting) is below kilobyte now,
about on par with what it used to be with one level of nested
symlinks and ~2.8 times lower than it used to be in the worst case.
- struct nameidata is entirely private to fs/namei.c now (not even
opaque pointers are being passed around).
- ->follow_link() and ->put_link() calling conventions had been
changed; all in-tree filesystems converted, out-of-tree should be
able to follow reasonably easily.
For out-of-tree conversions, see Documentation/filesystems/porting
for details (and in-tree filesystems for examples of conversion).
That has sat in -next since mid-May, seems to survive all testing
without regressions and merges clean with v4.1"
* 'for-linus-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (131 commits)
turn user_{path_at,path,lpath,path_dir}() into static inlines
namei: move saved_nd pointer into struct nameidata
inline user_path_create()
inline user_path_parent()
namei: trim do_last() arguments
namei: stash dfd and name into nameidata
namei: fold path_cleanup() into terminate_walk()
namei: saner calling conventions for filename_parentat()
namei: saner calling conventions for filename_create()
namei: shift nameidata down into filename_parentat()
namei: make filename_lookup() reject ERR_PTR() passed as name
namei: shift nameidata inside filename_lookup()
namei: move putname() call into filename_lookup()
namei: pass the struct path to store the result down into path_lookupat()
namei: uninline set_root{,_rcu}()
namei: be careful with mountpoint crossings in follow_dotdot_rcu()
Documentation: remove outdated information from automount-support.txt
get rid of assorted nameidata-related debris
lustre: kill unused helper
lustre: kill unused macro (LOOKUP_CONTINUE)
...
Move kernfs_get_inode() prototype from fs/kernfs/kernfs-internal.h to
include/linux/kernfs.h. It obtains the matching inode for a
kernfs_node.
It will be used by cgroup for inode based permission checks for now
but is generally useful.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Grabbing the parent is not happening anymore since 2010 (e72ceb8cca
"sysfs: Remove sysfs_get/put_active_two"). Remove this confusing
comment.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
root->ino_ida is used for kernfs inode number allocations. Since IDA has
a layered structure, different IDs can reside on the same layer, which
is currently accounted to some memory cgroup. The problem is that each
kmem cache of a memory cgroup has its own directory on sysfs (under
/sys/fs/kernel/<cache-name>/cgroup). If the inode number of such a
directory or any file in it gets allocated from a layer accounted to the
cgroup which the cache is created for, the cgroup will get pinned for
good, because one has to free all kmem allocations accounted to a cgroup
in order to release it and destroy all its kmem caches. That said we
must not account layers of ino_ida to any memory cgroup.
Since per net init operations may create new sysfs entries directly
(e.g. lo device) or indirectly (nf_conntrack creates a new kmem cache
per each namespace, which, in turn, creates new sysfs entries), an easy
way to reproduce this issue is by creating network namespace(s) from
inside a kmem-active memory cgroup.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org> [4.0.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
a) instead of storing the symlink body (via nd_set_link()) and returning
an opaque pointer later passed to ->put_link(), ->follow_link() _stores_
that opaque pointer (into void * passed by address by caller) and returns
the symlink body. Returning ERR_PTR() on error, NULL on jump (procfs magic
symlinks) and pointer to symlink body for normal symlinks. Stored pointer
is ignored in all cases except the last one.
Storing NULL for opaque pointer (or not storing it at all) means no call
of ->put_link().
b) the body used to be passed to ->put_link() implicitly (via nameidata).
Now only the opaque pointer is. In the cases when we used the symlink body
to free stuff, ->follow_link() now should store it as opaque pointer in addition
to returning it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
that's the bulk of filesystem drivers dealing with inodes of their own
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Kernfs supports two styles of read: direct_read and seqfile_read.
The latter supports 'poll' correctly thanks to the update of
'->event' in kernfs_seq_show.
The former does not as '->event' is never updated on a read.
So add an appropriate update in kernfs_file_direct_read().
This was noticed because some 'md' sysfs attributes were
recently changed to use direct reads.
Reported-by: Prakash Punnoor <prakash@punnoor.de>
Reported-by: Torsten Kaiser <just.for.lkml@googlemail.com>
Fixes: 750f199ee8
Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a new kernfs node is created, KERNFS_STATIC_NAME is used to avoid
making a separate copy of its name. It's currently only used for sysfs
attributes whose filenames are required to stay accessible and unchanged.
There are rare exceptions where these names are allocated and formatted
dynamically but for the vast majority of cases they're consts in the
rodata section.
Now that kernfs is converted to use kstrdup_const() and kfree_const(),
there's little point in keeping KERNFS_STATIC_NAME around. Remove it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Guenter Roeck