We have a MAX_LFS_FILESIZE macro that is meant to be filled in by
filesystems (and other IO targets) that know they are 64-bit clean and
don't have any 32-bit limits in their IO path.
It turns out that our 32-bit value for that limit was bogus. On 32-bit,
the VM layer is limited by the page cache to only 32-bit index values,
but our logic for that was confusing and actually wrong. We used to
define that value to
(((loff_t)PAGE_SIZE << (BITS_PER_LONG-1))-1)
which is actually odd in several ways: it limits the index to 31 bits,
and then it limits files so that they can't have data in that last byte
of a page that has the highest 31-bit index (ie page index 0x7fffffff).
Neither of those limitations make sense. The index is actually the full
32 bit unsigned value, and we can use that whole full page. So the
maximum size of the file would logically be "PAGE_SIZE << BITS_PER_LONG".
However, we do wan tto avoid the maximum index, because we have code
that iterates over the page indexes, and we don't want that code to
overflow. So the maximum size of a file on a 32-bit host should
actually be one page less than the full 32-bit index.
So the actual limit is ULONG_MAX << PAGE_SHIFT. That means that we will
not actually be using the page of that last index (ULONG_MAX), but we
can grow a file up to that limit.
The wrong value of MAX_LFS_FILESIZE actually caused problems for Doug
Nazar, who was still using a 32-bit host, but with a 9.7TB 2 x RAID5
volume. It turns out that our old MAX_LFS_FILESIZE was 8TiB (well, one
byte less), but the actual true VM limit is one page less than 16TiB.
This was invisible until commit c2a9737f45 ("vfs,mm: fix a dead loop
in truncate_inode_pages_range()"), which started applying that
MAX_LFS_FILESIZE limit to block devices too.
NOTE! On 64-bit, the page index isn't a limiter at all, and the limit is
actually just the offset type itself (loff_t), which is signed. But for
clarity, on 64-bit, just use the maximum signed value, and don't make
people have to count the number of 'f' characters in the hex constant.
So just use LLONG_MAX for the 64-bit case. That was what the value had
been before too, just written out as a hex constant.
Fixes: c2a9737f45 ("vfs,mm: fix a dead loop in truncate_inode_pages_range()")
Reported-and-tested-by: Doug Nazar <nazard@nazar.ca>
Cc: Andreas Dilger <adilger@dilger.ca>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
randstruct plugin, including the task_struct.
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Merge tag 'gcc-plugins-v4.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull structure randomization updates from Kees Cook:
"Now that IPC and other changes have landed, enable manual markings for
randstruct plugin, including the task_struct.
This is the rest of what was staged in -next for the gcc-plugins, and
comes in three patches, largest first:
- mark "easy" structs with __randomize_layout
- mark task_struct with an optional anonymous struct to isolate the
__randomize_layout section
- mark structs to opt _out_ of automated marking (which will come
later)
And, FWIW, this continues to pass allmodconfig (normal and patched to
enable gcc-plugins) builds of x86_64, i386, arm64, arm, powerpc, and
s390 for me"
* tag 'gcc-plugins-v4.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
randstruct: opt-out externally exposed function pointer structs
task_struct: Allow randomized layout
randstruct: Mark various structs for randomization
Pull ->s_options removal from Al Viro:
"Preparations for fsmount/fsopen stuff (coming next cycle). Everything
gets moved to explicit ->show_options(), killing ->s_options off +
some cosmetic bits around fs/namespace.c and friends. Basically, the
stuff needed to work with fsmount series with minimum of conflicts
with other work.
It's not strictly required for this merge window, but it would reduce
the PITA during the coming cycle, so it would be nice to have those
bits and pieces out of the way"
* 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
isofs: Fix isofs_show_options()
VFS: Kill off s_options and helpers
orangefs: Implement show_options
9p: Implement show_options
isofs: Implement show_options
afs: Implement show_options
affs: Implement show_options
befs: Implement show_options
spufs: Implement show_options
bpf: Implement show_options
ramfs: Implement show_options
pstore: Implement show_options
omfs: Implement show_options
hugetlbfs: Implement show_options
VFS: Don't use save/replace_mount_options if not using generic_show_options
VFS: Provide empty name qstr
VFS: Make get_filesystem() return the affected filesystem
VFS: Clean up whitespace in fs/namespace.c and fs/super.c
Provide a function to create a NUL-terminated string from unterminated data
Pull overlayfs updates from Miklos Szeredi:
"This work from Amir introduces the inodes index feature, which
provides:
- hardlinks are not broken on copy up
- infrastructure for overlayfs NFS export
This also fixes constant st_ino for samefs case for lower hardlinks"
* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (33 commits)
ovl: mark parent impure and restore timestamp on ovl_link_up()
ovl: document copying layers restrictions with inodes index
ovl: cleanup orphan index entries
ovl: persistent overlay inode nlink for indexed inodes
ovl: implement index dir copy up
ovl: move copy up lock out
ovl: rearrange copy up
ovl: add flag for upper in ovl_entry
ovl: use struct copy_up_ctx as function argument
ovl: base tmpfile in workdir too
ovl: factor out ovl_copy_up_inode() helper
ovl: extract helper to get temp file in copy up
ovl: defer upper dir lock to tempfile link
ovl: hash overlay non-dir inodes by copy up origin
ovl: cleanup bad and stale index entries on mount
ovl: lookup index entry for copy up origin
ovl: verify index dir matches upper dir
ovl: verify upper root dir matches lower root dir
ovl: introduce the inodes index dir feature
ovl: generalize ovl_create_workdir()
...
Kill off s_options, save/replace_mount_options() and generic_show_options()
as all filesystems now implement ->show_options() for themselves. This
should make it easier to implement a context-based mount where the mount
options can be passed individually over a file descriptor.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The madvise policy for transparent huge pages is meant to avoid unwanted
allocations of transparent huge pages. It allows a policy of disabling
the extra memory pressure and effort to arrange for a huge page when it
is not needed.
DAX by definition never incurs this overhead since it is statically
allocated. The policy choice makes even less sense for device-dax which
tries to guarantee a given tlb-fault size. Specifically, the following
setting:
echo never > /sys/kernel/mm/transparent_hugepage/enabled
...violates that guarantee and silently disables all device-dax
instances with a 2M or 1G alignment. So, let's avoid that non-obvious
side effect by force enabling thp for dax mappings in all cases.
It is worth noting that the reason this uses vma_is_dax(), and the
resulting header include changes, is that previous attempts to add a
VM_DAX flag were NAKd.
Link: http://lkml.kernel.org/r/149739531127.20686.15813586620597484283.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'for-linus-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux
Pull Writeback error handling updates from Jeff Layton:
"This pile represents the bulk of the writeback error handling fixes
that I have for this cycle. Some of the earlier patches in this pile
may look trivial but they are prerequisites for later patches in the
series.
The aim of this set is to improve how we track and report writeback
errors to userland. Most applications that care about data integrity
will periodically call fsync/fdatasync/msync to ensure that their
writes have made it to the backing store.
For a very long time, we have tracked writeback errors using two flags
in the address_space: AS_EIO and AS_ENOSPC. Those flags are set when a
writeback error occurs (via mapping_set_error) and are cleared as a
side-effect of filemap_check_errors (as you noted yesterday). This
model really sucks for userland.
Only the first task to call fsync (or msync or fdatasync) will see the
error. Any subsequent task calling fsync on a file will get back 0
(unless another writeback error occurs in the interim). If I have
several tasks writing to a file and calling fsync to ensure that their
writes got stored, then I need to have them coordinate with one
another. That's difficult enough, but in a world of containerized
setups that coordination may even not be possible.
But wait...it gets worse!
The calls to filemap_check_errors can be buried pretty far down in the
call stack, and there are internal callers of filemap_write_and_wait
and the like that also end up clearing those errors. Many of those
callers ignore the error return from that function or return it to
userland at nonsensical times (e.g. truncate() or stat()). If I get
back -EIO on a truncate, there is no reason to think that it was
because some previous writeback failed, and a subsequent fsync() will
(incorrectly) return 0.
This pile aims to do three things:
1) ensure that when a writeback error occurs that that error will be
reported to userland on a subsequent fsync/fdatasync/msync call,
regardless of what internal callers are doing
2) report writeback errors on all file descriptions that were open at
the time that the error occurred. This is a user-visible change,
but I think most applications are written to assume this behavior
anyway. Those that aren't are unlikely to be hurt by it.
3) document what filesystems should do when there is a writeback
error. Today, there is very little consistency between them, and a
lot of cargo-cult copying. We need to make it very clear what
filesystems should do in this situation.
To achieve this, the set adds a new data type (errseq_t) and then
builds new writeback error tracking infrastructure around that. Once
all of that is in place, we change the filesystems to use the new
infrastructure for reporting wb errors to userland.
Note that this is just the initial foray into cleaning up this mess.
There is a lot of work remaining here:
1) convert the rest of the filesystems in a similar fashion. Once the
initial set is in, then I think most other fs' will be fairly
simple to convert. Hopefully most of those can in via individual
filesystem trees.
2) convert internal waiters on writeback to use errseq_t for
detecting errors instead of relying on the AS_* flags. I have some
draft patches for this for ext4, but they are not quite ready for
prime time yet.
This was a discussion topic this year at LSF/MM too. If you're
interested in the gory details, LWN has some good articles about this:
https://lwn.net/Articles/718734/https://lwn.net/Articles/724307/"
* tag 'for-linus-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
btrfs: minimal conversion to errseq_t writeback error reporting on fsync
xfs: minimal conversion to errseq_t writeback error reporting
ext4: use errseq_t based error handling for reporting data writeback errors
fs: convert __generic_file_fsync to use errseq_t based reporting
block: convert to errseq_t based writeback error tracking
dax: set errors in mapping when writeback fails
Documentation: flesh out the section in vfs.txt on storing and reporting writeback errors
mm: set both AS_EIO/AS_ENOSPC and errseq_t in mapping_set_error
fs: new infrastructure for writeback error handling and reporting
lib: add errseq_t type and infrastructure for handling it
mm: don't TestClearPageError in __filemap_fdatawait_range
mm: clear AS_EIO/AS_ENOSPC when writeback initiation fails
jbd2: don't clear and reset errors after waiting on writeback
buffer: set errors in mapping at the time that the error occurs
fs: check for writeback errors after syncing out buffers in generic_file_fsync
buffer: use mapping_set_error instead of setting the flag
mm: fix mapping_set_error call in me_pagecache_dirty
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Merge tag 'for-linus-v4.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux
Pull Writeback error handling fixes from Jeff Layton:
"The main rationale for all of these changes is to tighten up writeback
error reporting to userland. There are many ways now that writeback
errors can be lost, such that fsync/fdatasync/msync return 0 when
writeback actually failed.
This pile contains a small set of cleanups and writeback error
handling fixes that I was able to break off from the main pile (#2).
Two of the patches in this pile are trivial. The exceptions are the
patch to fix up error handling in write_one_page, and the patch to
make JFS pay attention to write_one_page errors"
* tag 'for-linus-v4.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
fs: remove call_fsync helper function
mm: clean up error handling in write_one_page
JFS: do not ignore return code from write_one_page()
mm: drop "wait" parameter from write_one_page()
Most filesystems currently use mapping_set_error and
filemap_check_errors for setting and reporting/clearing writeback errors
at the mapping level. filemap_check_errors is indirectly called from
most of the filemap_fdatawait_* functions and from
filemap_write_and_wait*. These functions are called from all sorts of
contexts to wait on writeback to finish -- e.g. mostly in fsync, but
also in truncate calls, getattr, etc.
The non-fsync callers are problematic. We should be reporting writeback
errors during fsync, but many places spread over the tree clear out
errors before they can be properly reported, or report errors at
nonsensical times.
If I get -EIO on a stat() call, there is no reason for me to assume that
it is because some previous writeback failed. The fact that it also
clears out the error such that a subsequent fsync returns 0 is a bug,
and a nasty one since that's potentially silent data corruption.
This patch adds a small bit of new infrastructure for setting and
reporting errors during address_space writeback. While the above was my
original impetus for adding this, I think it's also the case that
current fsync semantics are just problematic for userland. Most
applications that call fsync do so to ensure that the data they wrote
has hit the backing store.
In the case where there are multiple writers to the file at the same
time, this is really hard to determine. The first one to call fsync will
see any stored error, and the rest get back 0. The processes with open
fds may not be associated with one another in any way. They could even
be in different containers, so ensuring coordination between all fsync
callers is not really an option.
One way to remedy this would be to track what file descriptor was used
to dirty the file, but that's rather cumbersome and would likely be
slow. However, there is a simpler way to improve the semantics here
without incurring too much overhead.
This set adds an errseq_t to struct address_space, and a corresponding
one is added to struct file. Writeback errors are recorded in the
mapping's errseq_t, and the one in struct file is used as the "since"
value.
This changes the semantics of the Linux fsync implementation such that
applications can now use it to determine whether there were any
writeback errors since fsync(fd) was last called (or since the file was
opened in the case of fsync having never been called).
Note that those writeback errors may have occurred when writing data
that was dirtied via an entirely different fd, but that's the case now
with the current mapping_set_error/filemap_check_error infrastructure.
This will at least prevent you from getting a false report of success.
The new behavior is still consistent with the POSIX spec, and is more
reliable for application developers. This patch just adds some basic
infrastructure for doing this, and ensures that the f_wb_err "cursor"
is properly set when a file is opened. Later patches will change the
existing code to use this new infrastructure for reporting errors at
fsync time.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Resetting this flag is almost certainly racy, and will be problematic
with some coming changes.
Make filemap_fdatawait_keep_errors return int, but not clear the flag(s).
Have jbd2 call it instead of filemap_fdatawait and don't attempt to
re-set the error flag if it fails.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Make get_filesystem() return a pointer to the filesystem on which it just
got a ref.
Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Pull read/write updates from Al Viro:
"Christoph's fs/read_write.c series - consolidation and cleanups"
* 'work.read_write' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
nfsd: remove nfsd_vfs_read
nfsd: use vfs_iter_read/write
fs: implement vfs_iter_write using do_iter_write
fs: implement vfs_iter_read using do_iter_read
fs: move more code into do_iter_read/do_iter_write
fs: remove __do_readv_writev
fs: remove do_compat_readv_writev
fs: remove do_readv_writev
Pull misc user access cleanups from Al Viro:
"The first pile is assorted getting rid of cargo-culted access_ok(),
cargo-culted set_fs() and field-by-field copyouts.
The same description applies to a lot of stuff in other branches -
this is just the stuff that didn't fit into a more specific topical
branch"
* 'work.misc-set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
Switch flock copyin/copyout primitives to copy_{from,to}_user()
fs/fcntl: return -ESRCH in f_setown when pid/pgid can't be found
fs/fcntl: f_setown, avoid undefined behaviour
fs/fcntl: f_setown, allow returning error
lpfc debugfs: get rid of pointless access_ok()
adb: get rid of pointless access_ok()
isdn: get rid of pointless access_ok()
compat statfs: switch to copy_to_user()
fs/locks: don't mess with the address limit in compat_fcntl64
nfsd_readlink(): switch to vfs_get_link()
drbd: ->sendpage() never needed set_fs()
fs/locks: pass kernel struct flock to fcntl_getlk/setlk
fs: locks: Fix some troubles at kernel-doc comments
Added an i_state flag I_INUSE and helpers to set/clear/test the bit.
The 'inuse' lock is an 'advisory' inode lock, that can be used to extend
exclusive create protection beyond parent->i_mutex lock among cooperating
users.
This is going to be used by overlayfs to get exclusive ownership on upper
and work dirs among overlayfs mounts.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Pull scheduler updates from Ingo Molnar:
"The main changes in this cycle were:
- Add the SYSTEM_SCHEDULING bootup state to move various scheduler
debug checks earlier into the bootup. This turns silent and
sporadically deadly bugs into nice, deterministic splats. Fix some
of the splats that triggered. (Thomas Gleixner)
- A round of restructuring and refactoring of the load-balancing and
topology code (Peter Zijlstra)
- Another round of consolidating ~20 of incremental scheduler code
history: this time in terms of wait-queue nomenclature. (I didn't
get much feedback on these renaming patches, and we can still
easily change any names I might have misplaced, so if anyone hates
a new name, please holler and I'll fix it.) (Ingo Molnar)
- sched/numa improvements, fixes and updates (Rik van Riel)
- Another round of x86/tsc scheduler clock code improvements, in hope
of making it more robust (Peter Zijlstra)
- Improve NOHZ behavior (Frederic Weisbecker)
- Deadline scheduler improvements and fixes (Luca Abeni, Daniel
Bristot de Oliveira)
- Simplify and optimize the topology setup code (Lauro Ramos
Venancio)
- Debloat and decouple scheduler code some more (Nicolas Pitre)
- Simplify code by making better use of llist primitives (Byungchul
Park)
- ... plus other fixes and improvements"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (103 commits)
sched/cputime: Refactor the cputime_adjust() code
sched/debug: Expose the number of RT/DL tasks that can migrate
sched/numa: Hide numa_wake_affine() from UP build
sched/fair: Remove effective_load()
sched/numa: Implement NUMA node level wake_affine()
sched/fair: Simplify wake_affine() for the single socket case
sched/numa: Override part of migrate_degrades_locality() when idle balancing
sched/rt: Move RT related code from sched/core.c to sched/rt.c
sched/deadline: Move DL related code from sched/core.c to sched/deadline.c
sched/cpuset: Only offer CONFIG_CPUSETS if SMP is enabled
sched/fair: Spare idle load balancing on nohz_full CPUs
nohz: Move idle balancer registration to the idle path
sched/loadavg: Generalize "_idle" naming to "_nohz"
sched/core: Drop the unused try_get_task_struct() helper function
sched/fair: WARN() and refuse to set buddy when !se->on_rq
sched/debug: Fix SCHED_WARN_ON() to return a value on !CONFIG_SCHED_DEBUG as well
sched/wait: Disambiguate wq_entry->task_list and wq_head->task_list naming
sched/wait: Move bit_wait_table[] and related functionality from sched/core.c to sched/wait_bit.c
sched/wait: Split out the wait_bit*() APIs from <linux/wait.h> into <linux/wait_bit.h>
sched/wait: Re-adjust macro line continuation backslashes in <linux/wait.h>
...
This marks many critical kernel structures for randomization. These are
structures that have been targeted in the past in security exploits, or
contain functions pointers, pointers to function pointer tables, lists,
workqueues, ref-counters, credentials, permissions, or are otherwise
sensitive. This initial list was extracted from Brad Spengler/PaX Team's
code in the last public patch of grsecurity/PaX based on my understanding
of the code. Changes or omissions from the original code are mine and
don't reflect the original grsecurity/PaX code.
Left out of this list is task_struct, which requires special handling
and will be covered in a subsequent patch.
Signed-off-by: Kees Cook <keescook@chromium.org>
De-dupliate some code and allow for passing the flags argument to
vfs_iter_write. Additionally it now properly updates timestamps.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
De-dupliate some code and allow for passing the flags argument to
vfs_iter_read. Additional it properly updates atime now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Define a set of write life time hints:
RWH_WRITE_LIFE_NOT_SET No hint information set
RWH_WRITE_LIFE_NONE No hints about write life time
RWH_WRITE_LIFE_SHORT Data written has a short life time
RWH_WRITE_LIFE_MEDIUM Data written has a medium life time
RWH_WRITE_LIFE_LONG Data written has a long life time
RWH_WRITE_LIFE_EXTREME Data written has an extremely long life time
The intent is for these values to be relative to each other, no
absolute meaning should be attached to these flag names.
Add an fcntl interface for querying these flags, and also for
setting them as well:
F_GET_RW_HINT Returns the read/write hint set on the
underlying inode.
F_SET_RW_HINT Set one of the above write hints on the
underlying inode.
F_GET_FILE_RW_HINT Returns the read/write hint set on the
file descriptor.
F_SET_FILE_RW_HINT Set one of the above write hints on the
file descriptor.
The user passes in a 64-bit pointer to get/set these values, and
the interface returns 0/-1 on success/error.
Sample program testing/implementing basic setting/getting of write
hints is below.
Add support for storing the write life time hint in the inode flags
and in struct file as well, and pass them to the kiocb flags. If
both a file and its corresponding inode has a write hint, then we
use the one in the file, if available. The file hint can be used
for sync/direct IO, for buffered writeback only the inode hint
is available.
This is in preparation for utilizing these hints in the block layer,
to guide on-media data placement.
/*
* writehint.c: get or set an inode write hint
*/
#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdbool.h>
#include <inttypes.h>
#ifndef F_GET_RW_HINT
#define F_LINUX_SPECIFIC_BASE 1024
#define F_GET_RW_HINT (F_LINUX_SPECIFIC_BASE + 11)
#define F_SET_RW_HINT (F_LINUX_SPECIFIC_BASE + 12)
#endif
static char *str[] = { "RWF_WRITE_LIFE_NOT_SET", "RWH_WRITE_LIFE_NONE",
"RWH_WRITE_LIFE_SHORT", "RWH_WRITE_LIFE_MEDIUM",
"RWH_WRITE_LIFE_LONG", "RWH_WRITE_LIFE_EXTREME" };
int main(int argc, char *argv[])
{
uint64_t hint;
int fd, ret;
if (argc < 2) {
fprintf(stderr, "%s: file <hint>\n", argv[0]);
return 1;
}
fd = open(argv[1], O_RDONLY);
if (fd < 0) {
perror("open");
return 2;
}
if (argc > 2) {
hint = atoi(argv[2]);
ret = fcntl(fd, F_SET_RW_HINT, &hint);
if (ret < 0) {
perror("fcntl: F_SET_RW_HINT");
return 4;
}
}
ret = fcntl(fd, F_GET_RW_HINT, &hint);
if (ret < 0) {
perror("fcntl: F_GET_RW_HINT");
return 3;
}
printf("%s: hint %s\n", argv[1], str[hint]);
close(fd);
return 0;
}
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
RWF_NOWAIT informs kernel to bail out if an AIO request will block
for reasons such as file allocations, or a writeback triggered,
or would block while allocating requests while performing
direct I/O.
RWF_NOWAIT is translated to IOCB_NOWAIT for iocb->ki_flags.
FMODE_AIO_NOWAIT is a flag which identifies the file opened is capable
of returning -EAGAIN if the AIO call will block. This must be set by
supporting filesystems in the ->open() call.
Filesystems xfs, btrfs and ext4 would be supported in the following patches.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
filemap_range_has_page() return true if the file's mapping has
a page within the range mentioned. This function will be used
to check if a write() call will cause a writeback of previous
writes.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Also added RWF_SUPPORTED to encompass all flags.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The wait_bit*() types and APIs are mixed into wait.h, but they
are a pretty orthogonal extension of wait-queues.
Furthermore, only about 50 kernel files use these APIs, while
over 1000 use the regular wait-queue functionality.
So clean up the main wait.h by moving the wait-bit functionality
out of it, into a separate .h and .c file:
include/linux/wait_bit.h for types and APIs
kernel/sched/wait_bit.c for the implementation
Update all header dependencies.
This reduces the size of wait.h rather significantly, by about 30%.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
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>
Allow f_setown to return an error value. We will fail in the next patch
with EINVAL for bad input to f_setown, so tile the path for the later
patch.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Cc: Jeff Layton <jlayton@poochiereds.net>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Jeff Layton <jlayton@redhat.com>
For some file systems we still memcpy into it, but in various places this
already allows us to use the proper uuid helpers. More to come..
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> (Changes to IMA/EVM)
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
This will make it easier to implement a sane compat fcntl syscall.
[ jlayton: fix undeclared identifiers in 32-bit fcntl64 syscall handler ]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
All uses of the current_fs_time() function have been replaced by other
time interfaces.
And, its use cases can be fulfilled by current_time() or ktime_get_*
variants.
Link: http://lkml.kernel.org/r/1491613030-11599-13-git-send-email-deepa.kernel@gmail.com
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Highlights include:
Stable bugfixes:
- Fix use after free in write error path
- Use GFP_NOIO for two allocations in writeback
- Fix a hang in OPEN related to server reboot
- Check the result of nfs4_pnfs_ds_connect
- Fix an rcu lock leak
Features:
- Removal of the unmaintained and unused OSD pNFS layout
- Cleanup and removal of lots of unnecessary dprintk()s
- Cleanup and removal of some memory failure paths now that
GFP_NOFS is guaranteed to never fail.
- Remove the v3-only data server limitation on pNFS/flexfiles
Bugfixes:
- RPC/RDMA connection handling bugfixes
- Copy offload: fixes to ensure the copied data is COMMITed to disk.
- Readdir: switch back to using the ->iterate VFS interface
- File locking fixes from Ben Coddington
- Various use-after-free and deadlock issues in pNFS
- Write path bugfixes
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Merge tag 'nfs-for-4.12-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
Pull NFS client updates from Trond Myklebust:
"Highlights include:
Stable bugfixes:
- Fix use after free in write error path
- Use GFP_NOIO for two allocations in writeback
- Fix a hang in OPEN related to server reboot
- Check the result of nfs4_pnfs_ds_connect
- Fix an rcu lock leak
Features:
- Removal of the unmaintained and unused OSD pNFS layout
- Cleanup and removal of lots of unnecessary dprintk()s
- Cleanup and removal of some memory failure paths now that GFP_NOFS
is guaranteed to never fail.
- Remove the v3-only data server limitation on pNFS/flexfiles
Bugfixes:
- RPC/RDMA connection handling bugfixes
- Copy offload: fixes to ensure the copied data is COMMITed to disk.
- Readdir: switch back to using the ->iterate VFS interface
- File locking fixes from Ben Coddington
- Various use-after-free and deadlock issues in pNFS
- Write path bugfixes"
* tag 'nfs-for-4.12-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (89 commits)
pNFS/flexfiles: Always attempt to call layoutstats when flexfiles is enabled
NFSv4.1: Work around a Linux server bug...
NFS append COMMIT after synchronous COPY
NFSv4: Fix exclusive create attributes encoding
NFSv4: Fix an rcu lock leak
nfs: use kmap/kunmap directly
NFS: always treat the invocation of nfs_getattr as cache hit when noac is on
Fix nfs_client refcounting if kmalloc fails in nfs4_proc_exchange_id and nfs4_proc_async_renew
NFSv4.1: RECLAIM_COMPLETE must handle NFS4ERR_CONN_NOT_BOUND_TO_SESSION
pNFS: Fix NULL dereference in pnfs_generic_alloc_ds_commits
pNFS: Fix a typo in pnfs_generic_alloc_ds_commits
pNFS: Fix a deadlock when coalescing writes and returning the layout
pNFS: Don't clear the layout return info if there are segments to return
pNFS: Ensure we commit the layout if it has been invalidated
pNFS: Don't send COMMITs to the DSes if the server invalidated our layout
pNFS/flexfiles: Fix up the ff_layout_write_pagelist failure path
pNFS: Ensure we check layout validity before marking it for return
NFS4.1 handle interrupted slot reuse from ERR_DELAY
NFSv4: check return value of xdr_inline_decode
nfs/filelayout: fix NULL pointer dereference in fl_pnfs_update_layout()
...
Pull misc vfs updates from Al Viro:
"Assorted bits and pieces from various people. No common topic in this
pile, sorry"
* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs/affs: add rename exchange
fs/affs: add rename2 to prepare multiple methods
Make stat/lstat/fstatat pass AT_NO_AUTOMOUNT to vfs_statx()
fs: don't set *REFERENCED on single use objects
fs: compat: Remove warning from COMPATIBLE_IOCTL
remove pointless extern of atime_need_update_rcu()
fs: completely ignore unknown open flags
fs: add a VALID_OPEN_FLAGS
fs: remove _submit_bh()
fs: constify tree_descr arrays passed to simple_fill_super()
fs: drop duplicate header percpu-rwsem.h
fs/affs: bugfix: Write files greater than page size on OFS
fs/affs: bugfix: enable writes on OFS disks
fs/affs: remove node generation check
fs/affs: import amigaffs.h
fs/affs: bugfix: make symbolic links work again
Commit afddba49d1 ("fs: introduce write_begin, write_end, and
perform_write aops") introduced AOP_FLAG_UNINTERRUPTIBLE flag which was
checked in pagecache_write_begin(), but that check was removed by
4e02ed4b4a ("fs: remove prepare_write/commit_write").
Between these two commits, commit d9414774dc ("cifs: Convert cifs to
new aops.") added a check in cifs_write_begin(), but that check was soon
removed by commit a98ee8c1c7 ("[CIFS] fix regression in
cifs_write_begin/cifs_write_end").
Therefore, AOP_FLAG_UNINTERRUPTIBLE flag is checked nowhere. Let's
remove this flag. This patch has no functionality changes.
Link: http://lkml.kernel.org/r/1489294781-53494-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
stat/lstat/fstatat need to pass AT_NO_AUTOMOUNT to vfs_statx() as the
pre-statx code didn't set LOOKUP_AUTOMOUNT, even though fstatat() accepted
the AT_NO_AUTOMOUNT flag.
Fixes: a528d35e8b ("statx: Add a system call to make enhanced file info available")
Reported-by: Ian Kent <raven@themaw.net>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Ian Kent <raven@themaw.net>
cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull fsnotify updates from Jan Kara:
"The branch contains mainly a rework of fsnotify infrastructure fixing
a shortcoming that we have waited for response to fanotify permission
events with SRCU read lock held and when the process consuming events
was slow to respond the kernel has stalled.
It also contains several cleanups of unnecessary indirections in
fsnotify framework and a bugfix from Amir fixing leakage of kernel
internal errno to userspace"
* 'fsnotify' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: (37 commits)
fanotify: don't expose EOPENSTALE to userspace
fsnotify: remove a stray unlock
fsnotify: Move ->free_mark callback to fsnotify_ops
fsnotify: Add group pointer in fsnotify_init_mark()
fsnotify: Drop inode_mark.c
fsnotify: Remove fsnotify_find_{inode|vfsmount}_mark()
fsnotify: Remove fsnotify_detach_group_marks()
fsnotify: Rename fsnotify_clear_marks_by_group_flags()
fsnotify: Inline fsnotify_clear_{inode|vfsmount}_mark_group()
fsnotify: Remove fsnotify_recalc_{inode|vfsmount}_mask()
fsnotify: Remove fsnotify_set_mark_{,ignored_}mask_locked()
fanotify: Release SRCU lock when waiting for userspace response
fsnotify: Pass fsnotify_iter_info into handle_event handler
fsnotify: Provide framework for dropping SRCU lock in ->handle_event
fsnotify: Remove special handling of mark destruction on group shutdown
fsnotify: Detach mark from object list when last reference is dropped
fsnotify: Move queueing of mark for destruction into fsnotify_put_mark()
inotify: Do not drop mark reference under idr_lock
fsnotify: Free fsnotify_mark_connector when there is no mark attached
fsnotify: Lock object list with connector lock
...
simple_fill_super() is passed an array of tree_descr structures which
describe the files to create in the filesystem's root directory. Since
these arrays are never modified intentionally, they should be 'const' so
that they are placed in .rodata and benefit from memory protection.
This patch updates the function signature and all users, and also
constifies tree_descr.name.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Drop duplicate header percpu-rwsem.h from linux/fs.h.
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Set FL_CLOSE in fl_flags as in locks_remove_posix() when clearing locks.
NFS will check for this flag to ensure an unlock is sent in a following
patch.
Fuse handles flock and posix locks differently for FL_CLOSE, and so
requires a fixup to retain the existing behavior for flock.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Now that all bdi structures filesystems use are properly refcounted, we
can remove the SB_I_DYNBDI flag.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Currently we free fsnotify_mark_connector structure only when inode /
vfsmount is getting freed. This can however impose noticeable memory
overhead when marks get attached to inodes only temporarily. So free the
connector structure once the last mark is detached from the object.
Since notification infrastructure can be working with the connector
under the protection of fsnotify_mark_srcu, we have to be careful and
free the fsnotify_mark_connector only after SRCU period passes.
Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Currently notification marks are attached to object (inode or vfsmnt) by
a hlist_head in the object. The list is also protected by a spinlock in
the object. So while there is any mark attached to the list of marks,
the object must be pinned in memory (and thus e.g. last iput() deleting
inode cannot happen). Also for list iteration in fsnotify() to work, we
must hold fsnotify_mark_srcu lock so that mark itself and
mark->obj_list.next cannot get freed. Thus we are required to wait for
response to fanotify events from userspace process with
fsnotify_mark_srcu lock held. That causes issues when userspace process
is buggy and does not reply to some event - basically the whole
notification subsystem gets eventually stuck.
So to be able to drop fsnotify_mark_srcu lock while waiting for
response, we have to pin the mark in memory and make sure it stays in
the object list (as removing the mark waiting for response could lead to
lost notification events for groups later in the list). However we don't
want inode reclaim to block on such mark as that would lead to system
just locking up elsewhere.
This commit is the first in the series that paves way towards solving
these conflicting lifetime needs. Instead of anchoring the list of marks
directly in the object, we anchor it in a dedicated structure
(fsnotify_mark_connector) and just point to that structure from the
object. The following commits will also add spinlock protecting the list
and object pointer to the structure.
Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
With arm-linux-gcc-4.2, almost every file we build in the kernel ends up
with this warning:
include/linux/fs.h:2648: warning: comparison of unsigned expression < 0 is always false
Later versions don't have this problem, but it's easy enough to work
around.
Link: http://lkml.kernel.org/r/20161216105634.235457-12-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
Pull vfs pile two from Al Viro:
- orangefs fix
- series of fs/namei.c cleanups from me
- VFS stuff coming from overlayfs tree
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
orangefs: Use RCU for destroy_inode
vfs: use helper for calling f_op->fsync()
mm: use helper for calling f_op->mmap()
vfs: use helpers for calling f_op->{read,write}_iter()
vfs: pass type instead of fn to do_{loop,iter}_readv_writev()
vfs: extract common parts of {compat_,}do_readv_writev()
vfs: wrap write f_ops with file_{start,end}_write()
vfs: deny copy_file_range() for non regular files
vfs: deny fallocate() on directory
vfs: create vfs helper vfs_tmpfile()
namei.c: split unlazy_walk()
namei.c: fold the check for DCACHE_OP_REVALIDATE into d_revalidate()
lookup_fast(): clean up the logics around the fallback to non-rcu mode
namei: fold unlazy_link() into its sole caller
Replace all 1 << inode->i_blkbits and (1 << inode->i_blkbits) in fs
branch.
This patch also fixes multiple checkpatch warnings: WARNING: Prefer
'unsigned int' to bare use of 'unsigned'
Thanks to Andrew Morton for suggesting more appropriate function instead
of macro.
[geliangtang@gmail.com: truncate: use i_blocksize()]
Link: http://lkml.kernel.org/r/9c8b2cd83c8f5653805d43debde9fa8817e02fc4.1484895804.git.geliangtang@gmail.com
Link: http://lkml.kernel.org/r/1481319905-10126-1-git-send-email-fabf@skynet.be
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
