Commit Graph

169 Commits

Author SHA1 Message Date
Jan Kara
14da920014 fs: Protect write paths by sb_start_write - sb_end_write
There are several entry points which dirty pages in a filesystem.  mmap
(handled by block_page_mkwrite()), buffered write (handled by
__generic_file_aio_write()), splice write (generic_file_splice_write),
truncate, and fallocate (these can dirty last partial page - handled inside
each filesystem separately). Protect these places with sb_start_write() and
sb_end_write().

->page_mkwrite() calls are particularly complex since they are called with
mmap_sem held and thus we cannot use standard sb_start_write() due to lock
ordering constraints. We solve the problem by using a special freeze protection
sb_start_pagefault() which ranks below mmap_sem.

BugLink: https://bugs.launchpad.net/bugs/897421
Tested-by: Kamal Mostafa <kamal@canonical.com>
Tested-by: Peter M. Petrakis <peter.petrakis@canonical.com>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Tested-by: Massimo Morana <massimo.morana@canonical.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-31 09:45:47 +04:00
Jan Kara
eb04c28288 fs: Add freezing handling to mnt_want_write() / mnt_drop_write()
Most of places where we want freeze protection coincides with the places where
we also have remount-ro protection. So make mnt_want_write() and
mnt_drop_write() (and their _file alternative) prevent freezing as well.
For the few cases that are really interested only in remount-ro protection
provide new function variants.

BugLink: https://bugs.launchpad.net/bugs/897421
Tested-by: Kamal Mostafa <kamal@canonical.com>
Tested-by: Peter M. Petrakis <peter.petrakis@canonical.com>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Tested-by: Massimo Morana <massimo.morana@canonical.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-31 09:40:38 +04:00
Al Viro
b5bcdda327 take grabbing f->f_path to do_dentry_open()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-29 21:24:18 +04:00
Al Viro
765927b2d5 switch dentry_open() to struct path, make it grab references itself
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-23 00:01:29 +04:00
David Howells
55e4def0a6 VFS: Make chown() and lchown() call fchownat()
Make the chown() and lchown() syscalls jump to the fchownat() syscall with the
appropriate extra arguments.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:35:54 +04:00
Al Viro
c3c4f69424 do_dentry_open(): close the race with mark_files_ro() in failure exit
we want to take it out of mark_files_ro() reach *before* we start
checking if we ought to drop write access.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:35:50 +04:00
Al Viro
02e5180d99 do_dentry_open(): take initialization of file->f_path to caller
... and get rid of a couple of arguments and a pointless reassignment
in finish_open() case.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:54 +04:00
Al Viro
2a027e7a18 fold __dentry_open() into its sole caller
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:52 +04:00
Al Viro
96b7e579ad switch do_dentry_open() to returning int
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:49 +04:00
Al Viro
e45198a6ac make finish_no_open() return int
namely, 1 ;-)  That's what we want to return from ->atomic_open()
instances after finish_no_open().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:45 +04:00
Al Viro
30d9049474 kill struct opendata
Just pass struct file *.  Methods are happier that way...
There's no need to return struct file * from finish_open() now,
so let it return int.  Next: saner prototypes for parts in
namei.c

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:39 +04:00
Al Viro
a4a3bdd778 kill opendata->{mnt,dentry}
->filp->f_path is there for purpose...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:37 +04:00
Al Viro
3d8a00d209 don't modify od->filp at all
make put_filp() conditional on flag set by finish_open()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:33 +04:00
Al Viro
47237687d7 ->atomic_open() prototype change - pass int * instead of bool *
... and let finish_open() report having opened the file via that sucker.
Next step: don't modify od->filp at all.

[AV: FILE_CREATE was already used by cifs; Miklos' fix folded]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:31 +04:00
Miklos Szeredi
015c3bbcd8 vfs: remove open intents from nameidata
All users of open intents have been converted to use ->atomic_{open,create}.

This patch gets rid of nd->intent.open and related infrastructure.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:18 +04:00
Miklos Szeredi
d18e9008c3 vfs: add i_op->atomic_open()
Add a new inode operation which is called on the last component of an open.
Using this the filesystem can look up, possibly create and open the file in one
atomic operation.  If it cannot perform this (e.g. the file type turned out to
be wrong) it may signal this by returning NULL instead of an open struct file
pointer.

i_op->atomic_open() is only called if the last component is negative or needs
lookup.  Handling cached positive dentries here doesn't add much value: these
can be opened using f_op->open().  If the cached file turns out to be invalid,
the open can be retried, this time using ->atomic_open() with a fresh dentry.

For now leave the old way of using open intents in lookup and revalidate in
place.  This will be removed once all the users are converted.

David Howells noticed that if ->atomic_open() opens the file but does not create
it, handle_truncate() will be called on it even if it is not a regular file.
Fix this by checking the file type in this case too.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:33:04 +04:00
Linus Torvalds
332a2e1244 vfs: make O_PATH file descriptors usable for 'fchdir()'
We already use them for openat() and friends, but fchdir() also wants to
be able to use O_PATH file descriptors.  This should make it comparable
to the O_SEARCH of Solaris.  In particular, O_PATH allows you to access
(not-quite-open) a directory you don't have read persmission to, only
execute permission.

Noticed during development of multithread support for ksh93.

Reported-by: ольга крыжановская <olga.kryzhanovska@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org    # O_PATH introduced in 3.0+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-07 17:19:02 -07:00
Miklos Szeredi
50ee93afca vfs: nameidata_to_filp(): don't throw away file on error
If open fails, don't put the file.  This allows it to be reused if open needs to
be retried.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 12:12:01 -04:00
Miklos Szeredi
91daee988d vfs: nameidata_to_filp(): inline __dentry_open()
Copy __dentry_open() into nameidata_to_filp().

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 12:12:01 -04:00
Miklos Szeredi
78f71eff3c vfs: do_dentry_open(): don't put filp
Move put_filp() out to __dentry_open(), the only caller now.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 12:12:00 -04:00
Miklos Szeredi
90ad1a8ecb vfs: split __dentry_open()
Split __dentry_open() into two functions:

  do_dentry_open() - does most of the actual work, doesn't put file on failure
  open_check_o_direct() - after a successful open, checks direct_IO method

This will allow i_op->atomic_open to do just the file initialization and leave
the direct_IO checking to the VFS.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 12:12:00 -04:00
Linus Torvalds
644473e9c6 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull user namespace enhancements from Eric Biederman:
 "This is a course correction for the user namespace, so that we can
  reach an inexpensive, maintainable, and reasonably complete
  implementation.

  Highlights:
   - Config guards make it impossible to enable the user namespace and
     code that has not been converted to be user namespace safe.

   - Use of the new kuid_t type ensures the if you somehow get past the
     config guards the kernel will encounter type errors if you enable
     user namespaces and attempt to compile in code whose permission
     checks have not been updated to be user namespace safe.

   - All uids from child user namespaces are mapped into the initial
     user namespace before they are processed.  Removing the need to add
     an additional check to see if the user namespace of the compared
     uids remains the same.

   - With the user namespaces compiled out the performance is as good or
     better than it is today.

   - For most operations absolutely nothing changes performance or
     operationally with the user namespace enabled.

   - The worst case performance I could come up with was timing 1
     billion cache cold stat operations with the user namespace code
     enabled.  This went from 156s to 164s on my laptop (or 156ns to
     164ns per stat operation).

   - (uid_t)-1 and (gid_t)-1 are reserved as an internal error value.
     Most uid/gid setting system calls treat these value specially
     anyway so attempting to use -1 as a uid would likely cause
     entertaining failures in userspace.

   - If setuid is called with a uid that can not be mapped setuid fails.
     I have looked at sendmail, login, ssh and every other program I
     could think of that would call setuid and they all check for and
     handle the case where setuid fails.

   - If stat or a similar system call is called from a context in which
     we can not map a uid we lie and return overflowuid.  The LFS
     experience suggests not lying and returning an error code might be
     better, but the historical precedent with uids is different and I
     can not think of anything that would break by lying about a uid we
     can't map.

   - Capabilities are localized to the current user namespace making it
     safe to give the initial user in a user namespace all capabilities.

  My git tree covers all of the modifications needed to convert the core
  kernel and enough changes to make a system bootable to runlevel 1."

Fix up trivial conflicts due to nearby independent changes in fs/stat.c

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (46 commits)
  userns:  Silence silly gcc warning.
  cred: use correct cred accessor with regards to rcu read lock
  userns: Convert the move_pages, and migrate_pages permission checks to use uid_eq
  userns: Convert cgroup permission checks to use uid_eq
  userns: Convert tmpfs to use kuid and kgid where appropriate
  userns: Convert sysfs to use kgid/kuid where appropriate
  userns: Convert sysctl permission checks to use kuid and kgids.
  userns: Convert proc to use kuid/kgid where appropriate
  userns: Convert ext4 to user kuid/kgid where appropriate
  userns: Convert ext3 to use kuid/kgid where appropriate
  userns: Convert ext2 to use kuid/kgid where appropriate.
  userns: Convert devpts to use kuid/kgid where appropriate
  userns: Convert binary formats to use kuid/kgid where appropriate
  userns: Add negative depends on entries to avoid building code that is userns unsafe
  userns: signal remove unnecessary map_cred_ns
  userns: Teach inode_capable to understand inodes whose uids map to other namespaces.
  userns: Fail exec for suid and sgid binaries with ids outside our user namespace.
  userns: Convert stat to return values mapped from kuids and kgids
  userns: Convert user specfied uids and gids in chown into kuids and kgid
  userns: Use uid_eq gid_eq helpers when comparing kuids and kgids in the vfs
  ...
2012-05-23 17:42:39 -07:00
Eric W. Biederman
52137abe18 userns: Convert user specfied uids and gids in chown into kuids and kgid
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-05-03 03:29:34 -07:00
Eric W. Biederman
18815a1808 userns: Convert capabilities related permsion checks
- Use uid_eq when comparing kuids
  Use gid_eq when comparing kgids
- Use make_kuid(user_ns, 0) to talk about the user_namespace root uid

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-05-03 03:28:40 -07:00
Eric Paris
83d498569e SELinux: rename dentry_open to file_open
dentry_open takes a file, rename it to file_open

Signed-off-by: Eric Paris <eparis@redhat.com>
2012-04-09 12:22:50 -04:00
David Howells
1dce27c5aa Wrap accesses to the fd_sets in struct fdtable
Wrap accesses to the fd_sets in struct fdtable (for recording open files and
close-on-exec flags) so that we can move away from using fd_sets since we
abuse the fd_set structs by not allocating the full-sized structure under
normal circumstances and by non-core code looking at the internals of the
fd_sets.

The first abuse means that use of FD_ZERO() on these fd_sets is not permitted,
since that cannot be told about their abnormal lengths.

This introduces six wrapper functions for setting, clearing and testing
close-on-exec flags and fd-is-open flags:

	void __set_close_on_exec(int fd, struct fdtable *fdt);
	void __clear_close_on_exec(int fd, struct fdtable *fdt);
	bool close_on_exec(int fd, const struct fdtable *fdt);
	void __set_open_fd(int fd, struct fdtable *fdt);
	void __clear_open_fd(int fd, struct fdtable *fdt);
	bool fd_is_open(int fd, const struct fdtable *fdt);

Note that I've prepended '__' to the names of the set/clear functions because
they require the caller to hold a lock to use them.

Note also that I haven't added wrappers for looking behind the scenes at the
the array.  Possibly that should exist too.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120216174942.23314.1364.stgit@warthog.procyon.org.uk
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
2012-02-19 10:30:52 -08:00
Al Viro
cdcf116d44 switch security_path_chmod() to struct path *
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-06 23:16:53 -05:00
Al Viro
a218d0fdc5 switch open and mkdir syscalls to umode_t
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:55:19 -05:00
Al Viro
49f0a07672 switch sys_chmod()/sys_fchmod()/sys_fchmodat() to umode_t
SYSCALLx magic should take care of things, according to Linus...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:55:12 -05:00
Al Viro
2a79f17e4a vfs: mnt_drop_write_file()
new helper (wrapper around mnt_drop_write()) to be used in pair with
mnt_want_write_file().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:40 -05:00
J. Bruce Fields
f3c7691e8d leases: fix write-open/read-lease race
In setlease, we use i_writecount to decide whether we can give out a
read lease.

In open, we break leases before incrementing i_writecount.

There is therefore a window between the break lease and the i_writecount
increment when setlease could add a new read lease.

This would leave us with a simultaneous write open and read lease, which
shouldn't happen.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2011-10-28 14:59:00 +02:00
Al Viro
e57712ebeb merge fchmod() and fchmodat() guts, kill ancient broken kludge
The kludge in question is undocumented and doesn't work for 32bit
binaries on amd64, sparc64 and s390.  Passing (mode_t)-1 as
mode had (since 0.99.14v and contrary to behaviour of any
other Unix, prescriptions of POSIX, SuS and our own manpages)
was kinda-sorta no-op.  Note that any software relying on
that (and looking for examples shows none) would be visibly
broken on sparc64, where practically all userland is built
32bit.  No such complaints noticed...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-26 15:07:43 -04:00
Konstantin Khlebnikov
5a9a43646c vfs: use ERR_CAST for err-ptr tossing in lookup_instantiate_filp
Replace unclear (struct dentry *) to (struct file *) typecast with ERR_CAST() macro.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-22 19:42:13 -04:00
Tetsuo Handa
c212f9aaf9 fs: Use BUG_ON(!mnt) at dentry_open().
dentry_open() requires callers to pass a valid vfsmount.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-21 01:10:41 -04:00
Linus Torvalds
0f6e0e8448 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6: (33 commits)
  AppArmor: kill unused macros in lsm.c
  AppArmor: cleanup generated files correctly
  KEYS: Add an iovec version of KEYCTL_INSTANTIATE
  KEYS: Add a new keyctl op to reject a key with a specified error code
  KEYS: Add a key type op to permit the key description to be vetted
  KEYS: Add an RCU payload dereference macro
  AppArmor: Cleanup make file to remove cruft and make it easier to read
  SELinux: implement the new sb_remount LSM hook
  LSM: Pass -o remount options to the LSM
  SELinux: Compute SID for the newly created socket
  SELinux: Socket retains creator role and MLS attribute
  SELinux: Auto-generate security_is_socket_class
  TOMOYO: Fix memory leak upon file open.
  Revert "selinux: simplify ioctl checking"
  selinux: drop unused packet flow permissions
  selinux: Fix packet forwarding checks on postrouting
  selinux: Fix wrong checks for selinux_policycap_netpeer
  selinux: Fix check for xfrm selinux context algorithm
  ima: remove unnecessary call to ima_must_measure
  IMA: remove IMA imbalance checking
  ...
2011-03-16 09:15:43 -07:00
James Morris
a002951c97 Merge branch 'next' into for-linus 2011-03-16 09:41:17 +11:00
Al Viro
65cfc67223 readlinkat(), fchownat() and fstatat() with empty relative pathnames
For readlinkat() we simply allow empty pathname; it will fail unless
we have dfd equal to O_PATH-opened symlink, so we are outside of
POSIX scope here.  For fchownat() and fstatat() we allow AT_EMPTY_PATH;
let the caller explicitly ask for such behaviour.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-15 02:21:45 -04:00
Al Viro
1abf0c718f New kind of open files - "location only".
New flag for open(2) - O_PATH.  Semantics:
	* pathname is resolved, but the file itself is _NOT_ opened
as far as filesystem is concerned.
	* almost all operations on the resulting descriptors shall
fail with -EBADF.  Exceptions are:
	1) operations on descriptors themselves (i.e.
		close(), dup(), dup2(), dup3(), fcntl(fd, F_DUPFD),
		fcntl(fd, F_DUPFD_CLOEXEC, ...), fcntl(fd, F_GETFD),
		fcntl(fd, F_SETFD, ...))
	2) fcntl(fd, F_GETFL), for a common non-destructive way to
		check if descriptor is open
	3) "dfd" arguments of ...at(2) syscalls, i.e. the starting
		points of pathname resolution
	* closing such descriptor does *NOT* affect dnotify or
posix locks.
	* permissions are checked as usual along the way to file;
no permission checks are applied to the file itself.  Of course,
giving such thing to syscall will result in permission checks (at
the moment it means checking that starting point of ....at() is
a directory and caller has exec permissions on it).

fget() and fget_light() return NULL on such descriptors; use of
fget_raw() and fget_raw_light() is needed to get them.  That protects
existing code from dealing with those things.

There are two things still missing (they come in the next commits):
one is handling of symlinks (right now we refuse to open them that
way; see the next commit for semantics related to those) and another
is descriptor passing via SCM_RIGHTS datagrams.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-15 02:21:45 -04:00
Al Viro
73d049a40f open-style analog of vfs_path_lookup()
new function: file_open_root(dentry, mnt, name, flags) opens the file
vfs_path_lookup would arrive to.

Note that name can be empty; in that case the usual requirement that
dentry should be a directory is lifted.

open-coded equivalents switched to it, may_open() got down exactly
one caller and became static.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-14 09:15:28 -04:00
Al Viro
47c805dc2d switch do_filp_open() to struct open_flags
take calculation of open_flags by open(2) arguments into new helper
in fs/open.c, move filp_open() over there, have it and do_sys_open()
use that helper, switch exec.c callers of do_filp_open() to explicit
(and constant) struct open_flags.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-14 09:15:25 -04:00
Marco Stornelli
1ca551c6ca Check for immutable/append flag in fallocate path
In the fallocate path the kernel doesn't check for the immutable/append
flag. It's possible to have a race condition in this scenario: an
application open a file in read/write and it does something, meanwhile
root set the immutable flag on the file, the application at that point
can call fallocate with success. In addition, we don't allow to do any
unreserve operation on an append only file but only the reserve one.

Signed-off-by: Marco Stornelli <marco.stornelli@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-10 04:22:15 -05:00
James Morris
1cc26bada9 Merge branch 'master'; commit 'v2.6.38-rc7' into next 2011-03-08 10:55:06 +11:00
Linus Torvalds
2dab597441 Fix possible filp_cachep memory corruption
In commit 31e6b01f41 ("fs: rcu-walk for path lookup") we started doing
path lookup using RCU, which then falls back to a careful non-RCU lookup
in case of problems (LOOKUP_REVAL).  So do_filp_open() has this "re-do
the lookup carefully" looping case.

However, that means that we must not release the open-intent file data
if we are going to loop around and use it once more!

Fix this by moving the release of the open-intent data to the function
that allocates it (do_filp_open() itself) rather than the helper
functions that can get called multiple times (finish_open() and
do_last()).  This makes the logic for the lifetime of that field much
more obvious, and avoids the possible double free.

Reported-by: J. R. Okajima <hooanon05@yahoo.co.jp>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-11 15:53:38 -08:00
Mimi Zohar
890275b5eb IMA: maintain i_readcount in the VFS layer
ima_counts_get() updated the readcount and invalidated the PCR,
as necessary. Only update the i_readcount in the VFS layer.
Move the PCR invalidation checks to ima_file_check(), where it
belongs.

Maintaining the i_readcount in the VFS layer, will allow other
subsystems to use i_readcount.

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Eric Paris <eparis@redhat.com>
2011-02-10 07:51:44 -05:00
Christoph Hellwig
2fe17c1075 fallocate should be a file operation
Currently all filesystems except XFS implement fallocate asynchronously,
while XFS forced a commit.  Both of these are suboptimal - in case of O_SYNC
I/O we really want our allocation on disk, especially for the !KEEP_SIZE
case where we actually grow the file with user-visible zeroes.  On the
other hand always commiting the transaction is a bad idea for fast-path
uses of fallocate like for example in recent Samba versions.   Given
that block allocation is a data plane operation anyway change it from
an inode operation to a file operation so that we have the file structure
available that lets us check for O_SYNC.

This also includes moving the code around for a few of the filesystems,
and remove the already unnedded S_ISDIR checks given that we only wire
up fallocate for regular files.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-17 02:25:31 -05:00
Josef Bacik
79124f18b3 fs: add hole punching to fallocate
Hole punching has already been implemented by XFS and OCFS2, and has the
potential to be implemented on both BTRFS and EXT4 so we need a generic way to
get to this feature.  The simplest way in my mind is to add FALLOC_FL_PUNCH_HOLE
to fallocate() since it already looks like the normal fallocate() operation.
I've tested this patch with XFS and BTRFS to make sure XFS did what it's
supposed to do and that BTRFS failed like it was supposed to.  Thank you,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-12 20:16:43 -05:00
Al Viro
d893f1bc2a fix open/umount race
nameidata_to_filp() drops nd->path or transfers it to opened
file.  In the former case it's a Bad Idea(tm) to do mnt_drop_write()
on nd->path.mnt, since we might race with umount and vfsmount in
question might be gone already.

Fix: don't drop it, then...  IOW, have nameidata_to_filp() grab nd->path
in case it transfers it to file and do path_drop() in callers.  After
they are through with accessing nd->path...

Reported-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-29 04:14:56 -04:00
Nick Piggin
ee2ffa0dfd fs: cleanup files_lock locking
fs: cleanup files_lock locking

Lock tty_files with a new spinlock, tty_files_lock; provide helpers to
manipulate the per-sb files list; unexport the files_lock spinlock.

Cc: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-18 08:35:47 -04:00
Dmitry Torokhov
06b1e104b7 vfs: clarify that nonseekable_open() will never fail
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: John Kacur <jkacur@redhat.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>
2010-08-11 08:59:02 -07:00
Linus Torvalds
8c8946f509 Merge branch 'for-linus' of git://git.infradead.org/users/eparis/notify
* 'for-linus' of git://git.infradead.org/users/eparis/notify: (132 commits)
  fanotify: use both marks when possible
  fsnotify: pass both the vfsmount mark and inode mark
  fsnotify: walk the inode and vfsmount lists simultaneously
  fsnotify: rework ignored mark flushing
  fsnotify: remove global fsnotify groups lists
  fsnotify: remove group->mask
  fsnotify: remove the global masks
  fsnotify: cleanup should_send_event
  fanotify: use the mark in handler functions
  audit: use the mark in handler functions
  dnotify: use the mark in handler functions
  inotify: use the mark in handler functions
  fsnotify: send fsnotify_mark to groups in event handling functions
  fsnotify: Exchange list heads instead of moving elements
  fsnotify: srcu to protect read side of inode and vfsmount locks
  fsnotify: use an explicit flag to indicate fsnotify_destroy_mark has been called
  fsnotify: use _rcu functions for mark list traversal
  fsnotify: place marks on object in order of group memory address
  vfs/fsnotify: fsnotify_close can delay the final work in fput
  fsnotify: store struct file not struct path
  ...

Fix up trivial delete/modify conflict in fs/notify/inotify/inotify.c.
2010-08-10 11:39:13 -07:00