* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
inotify: fix type errors in interfaces
fix breakage in reiserfs_new_inode()
fix the treatment of jfs special inodes
vfs: remove duplicate code in get_fs_type()
add a vfs_fsync helper
sys_execve and sys_uselib do not call into fsnotify
zero i_uid/i_gid on inode allocation
inode->i_op is never NULL
ntfs: don't NULL i_op
isofs check for NULL ->i_op in root directory is dead code
affs: do not zero ->i_op
kill suid bit only for regular files
vfs: lseek(fd, 0, SEEK_CUR) race condition
We used to have rather schizophrenic set of checks for NULL ->i_op even
though it had been eliminated years ago. You'd need to go out of your
way to set it to NULL explicitly _and_ a bunch of code would die on
such inodes anyway. After killing two remaining places that still
did that bogosity, all that crap can go away.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
With the write_begin/write_end aops, page_symlink was broken because it
could no longer pass a GFP_NOFS type mask into the point where the
allocations happened. They are done in write_begin, which would always
assume that the filesystem can be entered from reclaim. This bug could
cause filesystem deadlocks.
The funny thing with having a gfp_t mask there is that it doesn't really
allow the caller to arbitrarily tinker with the context in which it can be
called. It couldn't ever be GFP_ATOMIC, for example, because it needs to
take the page lock. The only thing any callers care about is __GFP_FS
anyway, so turn that into a single flag.
Add a new flag for write_begin, AOP_FLAG_NOFS. Filesystems can now act on
this flag in their write_begin function. Change __grab_cache_page to
accept a nofs argument as well, to honour that flag (while we're there,
change the name to grab_cache_page_write_begin which is more instructive
and does away with random leading underscores).
This is really a more flexible way to go in the end anyway -- if a
filesystem happens to want any extra allocations aside from the pagecache
ones in ints write_begin function, it may now use GFP_KERNEL (rather than
GFP_NOFS) for common case allocations (eg. ocfs2_alloc_write_ctxt, for a
random example).
[kosaki.motohiro@jp.fujitsu.com: fix ubifs]
[kosaki.motohiro@jp.fujitsu.com: fix fuse]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@kernel.org> [2.6.28.x]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ Cleaned up the calling convention: just pass in the AOP flags
untouched to the grab_cache_page_write_begin() function. That
just simplifies everybody, and may even allow future expansion of the
logic. - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[AV: rediffed on top of unification of init_fs]
Initialization of init_fs still uses the deprecated RW_LOCK_UNLOCKED macro.
This patch updates it to use the __RW_LOCK_UNLOCKED(lock) macro.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
With all the nameidata removal there's no point anymore for this helper.
Of the three callers left two will go away with the next lookup series
anyway.
Also add proper kerneldoc to inode_permission as this is the main
permission check routine now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
No need for the nameidata in may_open - a struct path is enough.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
walk_init_root is a tiny helper that is marked __always_inline, has just
one caller and an unused argument. Just merge it into the caller.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We now pass on all MAY_ flags to the filesystems permission routines,
so remove the comment stating the contrary.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
On-disk data corruption could cause a page link to have its i_size set
to PAGE_SIZE (or a multiple thereof) and its contents all non-NUL.
NUL-terminate the link name to ensure this doesn't cause further
problems for the kernel.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Duane Griffin <duaneg@dghda.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Add new LSM hooks for path-based checks. Call them on directory-modifying
operations at the points where we still know the vfsmount involved.
Signed-off-by: Kentaro Takeda <takedakn@nttdata.co.jp>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Toshiharu Harada <haradats@nttdata.co.jp>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Conflicts:
fs/nfsd/nfs4recover.c
Manually fixed above to use new creds API functions, e.g.
nfs4_save_creds().
Signed-off-by: James Morris <jmorris@namei.org>
Peter Cordes is sorry that he rm'ed his swapfiles while they were in use,
he then had no pathname to swapoff. It's a curious little oversight, but
not one worth a lot of hackery. Kudos to Willy Tarreau for turning this
around from a discussion of synthetic pathnames to how to prevent unlink.
Mimic immutable: prohibit unlinking an active swapfile in may_delete()
(and don't worry my little head over the tiny race window).
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Willy Tarreau <w@1wt.eu>
Acked-by: Christoph Hellwig <hch@infradead.org>
Cc: Peter Cordes <peter@cordes.ca>
Cc: Bodo Eggert <7eggert@gmx.de>
Cc: David Newall <davidn@davidnewall.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.
Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().
Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Morris <jmorris@namei.org>
For execute permission on a regular files we need to check if file has
any execute bits at all, regardless of capabilites.
This check is normally performed by generic_permission() but was also
added to the case when the filesystem defines its own ->permission()
method. In the latter case the filesystem should be responsible for
performing this check.
Move the check from inode_permission() inside filesystems which are
not calling generic_permission().
Create a helper function execute_ok() that returns true if the inode
is a directory or if any execute bits are present in i_mode.
Also fix up the following code:
- coda control file is never executable
- sysctl files are never executable
- hfs_permission seems broken on MAY_EXEC, remove
- hfsplus_permission is eqivalent to generic_permission(), remove
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
This adds LOOKUP_RENAME_TARGET intent for lookup of rename destination.
LOOKUP_RENAME_TARGET is going to be used like LOOKUP_CREATE. But since
the destination of rename() can be existing directory entry, so it has a
difference. Although that difference doesn't matter in my usage, this
tells it to user of this intent.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
lookup_hash() with LOOKUP_PARENT is bogus. And this prepares to add
new intent on those path.
The user of LOOKUP_PARENT intent is nfs only, and it checks whether
nd->flags has LOOKUP_CREATE or LOOKUP_OPEN, so the result is same.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
This adds d_ancestor() instead of d_isparent(), then use it.
If new_dentry == old_dentry, is_subdir() returns 1, looks strange.
"new_dentry == old_dentry" is not subdir obviously. But I'm not
checking callers for now, so this keeps current behavior.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
New flag: LOOKUP_EXCL. Set before doing the final step of pathname
resolution on the paths that have LOOKUP_CREATE and O_EXCL.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... and don't pass bogus flags when we are just looking for parent.
Fold __path_lookup_intent_open() into path_lookup_open() while we
are at it; that's the only remaining caller.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
for July 17: early crash on x86-64)
SELinux needs MAY_APPEND to be passed down to the security hook.
Otherwise, we get permission denials when only append permission is
granted by policy even if the opening process specified O_APPEND.
Shows up as a regression in the ltp selinux testsuite, fixed by
this patch.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* do not pass nameidata; struct path is all the callers want.
* switch to new helpers:
user_path_at(dfd, pathname, flags, &path)
user_path(pathname, &path)
user_lpath(pathname, &path)
user_path_dir(pathname, &path) (fail if not a directory)
The last 3 are trivial macro wrappers for the first one.
* remove nameidata in callers.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* MAY_CHDIR is redundant - it's an equivalent of MAY_ACCESS
* MAY_ACCESS on fuse should affect only the last step of pathname resolution
* fchdir() and chroot() should pass MAY_ACCESS, for the same reason why
chdir() needs that.
* now that we pass MAY_ACCESS explicitly in all cases, LOOKUP_ACCESS can be
removed; it has no business being in nameidata.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... so we ought to pass MAY_CHDIR to vfs_permission() instead of having
it triggered on every step of preceding pathname resolution. LOOKUP_CHDIR
is killed by that.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Remove the unused mode parameter from vfs_symlink and callers.
Thanks to Tetsuo Handa for noticing.
CC: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Why not reuse "inode" which is assigned as
struct inode *inode = old_dentry->d_inode;
in the beginning of vfs_link() ?
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* kill nameidata * argument; map the 3 bits in ->flags anybody cares
about to new MAY_... ones and pass with the mask.
* kill redundant gfs2_iop_permission()
* sanitize ecryptfs_permission()
* fix remaining places where ->permission() instances might barf on new
MAY_... found in mask.
The obvious next target in that direction is permission(9)
folded fix for nfs_permission() breakage from Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Lookup can install a child dentry for a deleted directory. This keeps
the directory dentry alive, and the inode pinned in the cache and on
disk, even after all external references have gone away.
This isn't a big problem normally, since memory pressure or umount
will clear out the directory dentry and its children, releasing the
inode. But for UBIFS this causes problems because its orphan area can
overflow.
Fix this by returning ENOENT for all lookups on a S_DEAD directory
before creating a child dentry.
Thanks to Zoltan Sogor for noticing this while testing UBIFS, and
Artem for the excellent analysis of the problem and testing.
Reported-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Tested-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
generic_readlink calls ERR_PTR for negative and positive values
(vfs_readlink returns length of "link"), but it should not
(not an errno) and does not need to.
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Acked-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Here are some more places where path_{get,put}() can be used instead of
dput()/mntput() pair.
Signed-off-by: Jan Blunck <jblunck@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
In case when both EEXIST and EROFS would apply we used to
return the former in mkdir(2) and friends. Lest anyone suspects
us of being consistent, in the same situation knfsd gave clients
nfs_erofs...
ro-bind series had switched the syscall side of things to
returning -EROFS and immediately broke an application - namely,
mkdir -p. Patch restores the original behaviour...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Implement a cgroup to track and enforce open and mknod restrictions on device
files. A device cgroup associates a device access whitelist with each cgroup.
A whitelist entry has 4 fields. 'type' is a (all), c (char), or b (block).
'all' means it applies to all types and all major and minor numbers. Major
and minor are either an integer or * for all. Access is a composition of r
(read), w (write), and m (mknod).
The root device cgroup starts with rwm to 'all'. A child devcg gets a copy of
the parent. Admins can then remove devices from the whitelist or add new
entries. A child cgroup can never receive a device access which is denied its
parent. However when a device access is removed from a parent it will not
also be removed from the child(ren).
An entry is added using devices.allow, and removed using
devices.deny. For instance
echo 'c 1:3 mr' > /cgroups/1/devices.allow
allows cgroup 1 to read and mknod the device usually known as
/dev/null. Doing
echo a > /cgroups/1/devices.deny
will remove the default 'a *:* mrw' entry.
CAP_SYS_ADMIN is needed to change permissions or move another task to a new
cgroup. A cgroup may not be granted more permissions than the cgroup's parent
has. Any task can move itself between cgroups. This won't be sufficient, but
we can decide the best way to adequately restrict movement later.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix may-be-used-uninitialized warning]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: James Morris <jmorris@namei.org>
Looks-good-to: Pavel Emelyanov <xemul@openvz.org>
Cc: Daniel Hokka Zakrisson <daniel@hozac.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the first really tricky patch in the series. It elevates the writer
count on a mount each time a non-special file is opened for write.
We used to do this in may_open(), but Miklos pointed out that __dentry_open()
is used as well to create filps. This will cover even those cases, while a
call in may_open() would not have.
There is also an elevated count around the vfs_create() call in open_namei().
See the comments for more details, but we need this to fix a 'create, remount,
fail r/w open()' race.
Some filesystems forego the use of normal vfs calls to create
struct files. Make sure that these users elevate the mnt
writer count because they will get __fput(), and we need
to make sure they're balanced.
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This also uses the little helper in the NFS code to make an if() a little bit
less ugly. We introduced the helper at the beginning of the series.
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This takes care of all of the direct callers of vfs_mknod().
Since a few of these cases also handle normal file creation
as well, this also covers some calls to vfs_create().
So that we don't have to make three mnt_want/drop_write()
calls inside of the switch statement, we move some of its
logic outside of the switch and into a helper function
suggested by Christoph.
This also encapsulates a fix for mknod(S_IFREG) that Miklos
found.
[AV: merged mkdir handling, added missing nfsd pieces]
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Elevate the write count during the vfs_rmdir() and vfs_unlink().
[AV: merged rmdir and unlink parts, added missing pieces in nfsd]
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
open_namei() will, in the future, need to take mount write counts
over its creation and truncation (via may_open()) operations. It
needs to keep these write counts until any potential filp that is
created gets __fput()'d.
This gets complicated in the error handling and becomes very murky
as to how far open_namei() actually got, and whether or not that
mount write count was taken. That makes it a bad interface.
All that the current do_filp_open() really does is allocate the
nameidata on the stack, then call open_namei().
So, this merges those two functions and moves filp_open() over
to namei.c so it can be close to its buddy: do_filp_open(). It
also gets a kerneldoc comment in the process.
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
My end goal here is to make sure all users of may_open()
return filps. This will ensure that we properly release
mount write counts which were taken for the filp in
may_open().
This patch moves the sys_open flags to namei flags
calculation into fs/namei.c. We'll shortly be moving
the nameidata_to_filp() calls into namei.c, and this
gets the sys_open flags to a place where we can get
at them when we need them.
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
[PATCH] get stack footprint of pathname resolution back to relative sanity
[PATCH] double iput() on failure exit in hugetlb
[PATCH] double dput() on failure exit in tiny-shmem
[PATCH] fix up new filp allocators
[PATCH] check for null vfsmount in dentry_open()
[PATCH] reiserfs: eliminate private use of struct file in xattr
[PATCH] sanitize hppfs
hppfs pass vfsmount to dentry_open()
[PATCH] restore export of do_kern_mount()
Fix kernel-doc notation warnings in fs/.
Warning(mmotm-2008-0314-1449//fs/super.c:560): missing initial short description on line:
* mark_files_ro
Warning(mmotm-2008-0314-1449//fs/locks.c:1277): missing initial short description on line:
* lease_get_mtime
Warning(mmotm-2008-0314-1449//fs/locks.c:1277): missing initial short description on line:
* lease_get_mtime
Warning(mmotm-2008-0314-1449//fs/namei.c:1368): missing initial short description on line:
* lookup_one_len: filesystem helper to lookup single pathname component
Warning(mmotm-2008-0314-1449//fs/buffer.c:3221): missing initial short description on line:
* bh_uptodate_or_lock: Test whether the buffer is uptodate
Warning(mmotm-2008-0314-1449//fs/buffer.c:3240): missing initial short description on line:
* bh_submit_read: Submit a locked buffer for reading
Warning(mmotm-2008-0314-1449//fs/fs-writeback.c:30): missing initial short description on line:
* writeback_acquire: attempt to get exclusive writeback access to a device
Warning(mmotm-2008-0314-1449//fs/fs-writeback.c:47): missing initial short description on line:
* writeback_in_progress: determine whether there is writeback in progress
Warning(mmotm-2008-0314-1449//fs/fs-writeback.c:58): missing initial short description on line:
* writeback_release: relinquish exclusive writeback access against a device.
Warning(mmotm-2008-0314-1449//include/linux/jbd.h:351): contents before sections
Warning(mmotm-2008-0314-1449//include/linux/jbd.h:561): contents before sections
Warning(mmotm-2008-0314-1449//fs/jbd/transaction.c:1935): missing initial short description on line:
* void journal_invalidatepage()
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Somebody had put struct nameidata in stack frame of link_path_walk().
Unfortunately, there are certain realities to deal with:
* It's in the middle of recursion. Depth is equal to the nesting
depth of symlinks, i.e. up to 8.
* struct namiedata is, even if one discards the intent junk,
at least 12 pointers + 5 ints.
* moreover, adding a stack frame is not free in that situation.
* there are fs methods called on top of that, and they also have
stack footprint.
* kernel stack is not infinite.
The thing is, even if one chooses to deal with -ESTALE that way (and it's
one hell of an overkill), the only thing that needs to be preserved is
vfsmount + dentry, not the entire struct nameidata.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Use struct path in fs_struct.
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This introduces the symmetric function to path_put() for getting a reference
to the dentry and vfsmount of a struct path in the right order.
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use path_put() in a few places instead of {mnt,d}put()
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Add path_put() functions for releasing a reference to the dentry and
vfsmount of a struct path in the right order
* Switch from path_release(nd) to path_put(&nd->path)
* Rename dput_path() to path_put_conditional()
[akpm@linux-foundation.org: fix cifs]
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the central patch of a cleanup series. In most cases there is no good
reason why someone would want to use a dentry for itself. This series reflects
that fact and embeds a struct path into nameidata.
Together with the other patches of this series
- it enforced the correct order of getting/releasing the reference count on
<dentry,vfsmount> pairs
- it prepares the VFS for stacking support since it is essential to have a
struct path in every place where the stack can be traversed
- it reduces the overall code size:
without patch series:
text data bss dec hex filename
5321639 858418 715768 6895825 6938d1 vmlinux
with patch series:
text data bss dec hex filename
5320026 858418 715768 6894212 693284 vmlinux
This patch:
Switch from nd->{dentry,mnt} to nd->path.{dentry,mnt} everywhere.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix cifs]
[akpm@linux-foundation.org: fix smack]
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
path_release_on_umount() should only be called from sys_umount(). I merged the
function into sys_umount() instead of having in in namei.c.
Signed-off-by: Jan Blunck <jblunck@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
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>
Currently, no notification event has been sent when inode's link count
changed. This is inconvenient for the application in some cases:
Suppose you have the following directory structure
foo/test
bar/
and you watch test. If someone does "mv foo/test bar/", you get event
IN_MOVE_SELF and you know something has happened with the file "test".
However if someone does "ln foo/test bar/test" and "rm foo/test" you get no
inotify event for the file "test" (only directories "foo" and "bar" receive
events).
Furthermore it could be argued that link count belongs to file's metadata and
thus IN_ATTRIB should be sent when it changes.
The following patch implements sending of IN_ATTRIB inotify events when link
count of the inode changes, i.e., when a hardlink to the inode is created or
when it is removed. This event is sent in addition to all the events sent so
far. In particular, when a last link to a file is removed, IN_ATTRIB event is
sent in addition to IN_DELETE_SELF event.
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Morten Welinder <mwelinder@gmail.com>
Cc: Robert Love <rlove@google.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Steven French <sfrench@us.ibm.com>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Way back when (in commit 834f2a4a15, aka
"VFS: Allow the filesystem to return a full file pointer on open intent"
to be exact), Trond changed the open logic to keep track of the original
flags to a file open, in order to pass down the the intent of a dentry
lookup to the low-level filesystem.
However, when doing that reorganization, it changed the meaning of
namei_flags, and thus inadvertently changed the test of access mode for
directories (and RO filesystem) to use the wrong flag. So fix those
test back to use access mode ("acc_mode") rather than the open flag
("flag").
Issue noticed by Bill Roman at Datalight.
Reported-and-tested-by: Bill Roman <bill.roman@datalight.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a new attribute flag ATTR_OPEN, with the meaning: "truncation was
initiated by open() due to the O_TRUNC flag".
This way filesystems wanting to implement truncation within their ->open()
method can ignore such truncate requests.
This is a quick & dirty hack, but it comes for free.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger@clusterfs.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
First of all, this makes the structure jumping look a little bit cleaner. So,
this stands alone as a tiny cleanup. But, we also need 'mnt' by itself a few
more times later in this series, so this isn't _just_ a cleanup.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
may_open() calls vfs_permission() before it does checks for IS_RDONLY(inode).
It checks _again_ inside of vfs_permission().
The check inside of vfs_permission() is going away eventually. With the
mnt_want/drop_write() functions, all of the r/o checks (except for this one)
are consistently done before calling permission(). Because of this, I'd like
to use permission() to hold a debugging check to make sure that the
mnt_want/drop_write() calls are actually being made.
So, to do this:
1. remove the IS_RDONLY() check from permission()
2. enforce that you must mnt_want_write() before
even calling permission()
3. actually add the debugging check to permission()
We need to rearrange may_open() to do r/o checks before calling permission().
Here's the patch.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
permission() checks that MAY_EXEC is only allowed on regular files if at least
one execute bit is set in the file mode.
generic_permission() already ensures this, so the extra check in permission()
is superfluous.
If the filesystem defines it's own ->permission() the check may still be
needed. In this case move it after ->permission(). This is needed because
filesystems such as FUSE may need to refresh the inode attributes before
checking permissions.
This check should be moved inside ->permission(), but that's another story.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch cleans up duplicate includes in
fs/
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Try to fix the mess created by sysfs braindamage.
- refactor code internal to fs/namei.c a little to avoid too much
duplication:
o __lookup_hash_kern is renamed back to __lookup_hash
o the old __lookup_hash goes away, permission checks moves to
the two callers
o useless inline qualifiers on above functions go away
- lookup_one_len_kern loses it's last argument and is renamed to
lookup_one_noperm to make it's useage a little more clear
- added kerneldoc comments to describe lookup_one_len aswell as
lookup_one_noperm and make it very clear that no one should use
the latter ever.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
Cc: Miklos Szeredi <miklos@szeredi.hu>
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>
These are intended to replace prepare_write and commit_write with more
flexible alternatives that are also able to avoid the buffered write
deadlock problems efficiently (which prepare_write is unable to do).
[mark.fasheh@oracle.com: API design contributions, code review and fixes]
[akpm@linux-foundation.org: various fixes]
[dmonakhov@sw.ru: new aop block_write_begin fix]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Dmitriy Monakhov <dmonakhov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Neil Brown <neilb@suse.de>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Neil Brown <neilb@suse.de>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Stackable file systems, among others, frequently need to lookup paths or
path components starting from an arbitrary point in the namespace
(identified by a dentry and a vfsmount). Currently, such file systems use
lookup_one_len, which is frowned upon [1] as it does not pass the lookup
intent along; not passing a lookup intent, for example, can trigger BUG_ON's
when stacking on top of NFSv4.
The first patch introduces a new lookup function to allow lookup starting
from an arbitrary point in the namespace. This approach has been suggested
by Christoph Hellwig [2].
The second patch changes sunrpc to use vfs_path_lookup.
The third patch changes nfsctl.c to use vfs_path_lookup.
The fourth patch marks link_path_walk static.
The fifth, and last patch, unexports path_walk because it is no longer
unnecessary to call it directly, and using the new vfs_path_lookup is
cleaner.
For example, the following snippet of code, looks up "some/path/component"
in a directory pointed to by parent_{dentry,vfsmnt}:
err = vfs_path_lookup(parent_dentry, parent_vfsmnt,
"some/path/component", 0, &nd);
if (!err) {
/* exits */
...
/* once done, release the references */
path_release(&nd);
} else if (err == -ENOENT) {
/* doesn't exist */
} else {
/* other error */
}
VFS functions such as lookup_create can be used on the nameidata structure
to pass the create intent to the file system.
Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Neil Brown <neilb@suse.de>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce is_owner_or_cap() macro in fs.h, and convert over relevant
users to it. This is done because we want to avoid bugs in the future
where we check for only effective fsuid of the current task against a
file's owning uid, without simultaneously checking for CAP_FOWNER as
well, thus violating its semantics.
[ XFS uses special macros and structures, and in general looked ...
untouchable, so we leave it alone -- but it has been looked over. ]
The (current->fsuid != inode->i_uid) check in generic_permission() and
exec_permission_lite() is left alone, because those operations are
covered by CAP_DAC_OVERRIDE and CAP_DAC_READ_SEARCH. Similarly operations
falling under the purview of CAP_CHOWN and CAP_LEASE are also left alone.
Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Cc: Al Viro <viro@ftp.linux.org.uk>
Acked-by: Serge E. Hallyn <serge@hallyn.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Handle the edge cases for POSIX message queue auditing. Collect inode
info when opening an existing mq, and for send/receive operations. Remove
audit_inode_update() as it has really evolved into the equivalent of
audit_inode().
Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Since path_walk sets the total_link_count to 0 and calls link_path_walk, we
can just call path_walk directly.
Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.
Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We don't have a routine called namei() anymore since at least 2.3.x, and
the comment is just totally out of sync with the current lookup logic.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ensure pages are uptodate after returning from read_cache_page, which allows
us to cut out most of the filesystem-internal PageUptodate calls.
I didn't have a great look down the call chains, but this appears to fixes 7
possible use-before uptodate in hfs, 2 in hfsplus, 1 in jfs, a few in
ecryptfs, 1 in jffs2, and a possible cleared data overwritten with readpage in
block2mtd. All depending on whether the filler is async and/or can return
with a !uptodate page.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Prevent permission checking from being performed when the kernel wants to
unconditionally remove a sysfs group, by introducing an kernel-only variant
of lookup_one_len(), lookup_one_len_kern().
Additionally, as sysfs_remove_group() does not check the return value of
the lookup before using it, a BUG_ON has been added to pinpoint the cause
of any problems potentially caused by this (and as a form of annotation).
Signed-off-by: James Morris <jmorris@namei.org>
Cc: Nagendra Singh Tomar <nagendra_tomar@adaptec.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
If prepare_write or commit_write return AOP_TRUNCATED_PAGE we jump to
"retry" label and than if find_or_create_page() failed function return
incorrect error code.
Signed-off-by: Dmitriy Monakhov <dmonakhov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Many struct inode_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch changes struct file to use struct path instead of having
independent pointers to struct dentry and struct vfsmount, and converts all
users of f_{dentry,vfsmnt} in fs/ to use f_path.{dentry,mnt}.
Additionally, it adds two #define's to make the transition easier for users of
the f_dentry and f_vfsmnt.
Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Moved struct path from fs/namei.c to include/linux/namei.h. This allows many
places in the VFS, as well as any stackable filesystem to easily keep track of
dentry-vfsmount pairs.
Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make access(X_OK) take the "noexec" mount option into account.
Signed-off-by: Stas Sergeev <stsp@aknet.ru>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The code around vfs_create() in open_namei() is getting a bit too complex.
Right now, there is at least the reference count on the dentry, and the
i_mutex to worry about. Soon, we'll also have mnt_writecount.
So, break the vfs_create() call out of open_namei(), and into a helper
function. This duplicates the call to may_open(), but that isn't such a bad
thing since the arguments (acc_mode and flag) were being heavily massaged
anyway.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We're shortly going to be adding a bunch more permission checks in these
functions. That requires adding either a bunch of new if() conditions, or
some gotos. This patch collapses existing if()s and uses gotos instead to
prepare for the upcoming changes.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Replace current->fs by fs helper variable to reduce some indirection
overhead and (at least at the moment, before the current_thread_info() %gs
PDA improvement is available) get rid of more costly current references.
Reduces fs/namei.o from 37786 to 37082 Bytes (704 Bytes saved).
[akpm@osdl.org: cleanup]
Signed-off-by: Andreas Mohr <andi@lisas.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
For a long time now I have had a problem with not being able to return a
lookup failure on an existsing directory. In autofs this corresponds to a
mount failure on a autofs managed mount entry that is browsable (and so the
mount point directory exists).
While this problem has been present for a long time I've avoided resolving
it because it was not very visible. But now that autofs v5 has "mount and
expire on demand" of nested multiple mounts, such as is found when mounting
an export list from a server, solving the problem cannot be avoided any
longer.
I've tried very hard to find a way to do this entirely within the autofs4
module but have not been able to find a satisfactory way to achieve it.
So, I need to propose a change to the VFS.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Some file systems want to manually d_move() the dentries involved in a
rename. We can do this by making use of the FS_ODD_RENAME flag if we just
have nfs_rename() unconditionally do the d_move(). While there, we rename
the flag to be more descriptive.
OCFS2 uses this to protect that part of the rename operation with a cluster
lock.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Currently, the access() call will return incorrect information on NFS if
there exists an ACL that grants execute access to the user on a regular
file. The reason the information is incorrect is that the VFS overrides
this execute access in open_exec() by checking (inode->i_mode & 0111).
This patch propagates the VFS execute bit check back into the generic
permission() call.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
(cherry picked from 64cbae98848c4c99851cb0a405f0b4982cd76c1e commit)
I'm trying to speeding up mkdir(2) for network file systems. A typical
mkdir(2) calls two inode_operations: lookup and mkdir. The lookup
operation would fail with ENOENT in common case. I think it is unnecessary
because the subsequent mkdir operation can check it. In case of creat(2),
lookup operation is called with the LOOKUP_CREATE flag, so individual
filesystem can omit real lookup. e.g. nfs_lookup().
Here is a sample patch which uses LOOKUP_CREATE and O_EXCL on mkdir,
symlink and mknod. This uses the gadget for creat(2).
And here is the result of a benchmark on NFSv3.
mkdir(2) 10,000 times:
original 50.5 sec
patched 29.0 sec
Signed-off-by: ASANO Masahiro <masano@tnes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
(cherry picked from fab7bf44449b29f9d5572a5dd8adcf7c91d5bf0f commit)
When an object is created via a symlink into an audited directory, audit misses
the event due to not having collected the inode data for the directory. Modify
__audit_inode_child() to copy the parent inode data if a parent wasn't found in
audit_names[].
Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When the specified path is an existing file or when it is a symlink, audit
collects the wrong inode number, which causes it to miss the open() event.
Adding a second hook to the open() path fixes this.
Also add audit_copy_inode() to consolidate some code.
Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2.6.16 leaks like hell. While testing, I found massive leakage
(reproduced in openvz) in:
*filp
*size-4096
And 1 object leaks in
*size-32
*size-64
*size-128
It is the fix for the first one. filp leaks in the bowels of namei.c.
Seems, size-4096 is file table leaking in expand_fdtables.
I have no idea what are the rest and why they show only accompanying
another leaks. Some debugging structs?
[akpm@osdl.org, Trond: remove the IS_ERR() check]
Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: <stable@kernel.org>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Teach special (recursive) locking code to the lock validator. Has no effect
on non-lockdep kernels.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When the linkat() syscall was added the flag parameter was added in the
last minute but it wasn't used so far. The following patch should change
that. My tests show that this is all that's needed.
If OLDNAME is a symlink setting the flag causes linkat to follow the
symlink and create a hardlink with the target. This is actually the
behavior POSIX demands for link() as well but Linux wisely does not do
this. With this flag (which will most likely be in the next POSIX
revision) the programmer can choose the behavior, defaulting to the safe
variant. As a side effect it is now possible to implement a
POSIX-compliant link(2) function for those who are interested.
touch file
ln -s file symlink
linkat(fd, "symlink", fd, "newlink", 0)
-> newlink is hardlink of symlink
linkat(fd, "symlink", fd, "newlink", AT_SYMLINK_FOLLOW)
-> newlink is hardlink of file
The value of AT_SYMLINK_FOLLOW is determined by the definition we already
use in glibc.
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add read_mapping_page() which is used for callers that pass
mapping->a_ops->readpage as the filler for read_cache_page. This removes
some duplication from filesystem code.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
From: Trond Myklebust <Trond.Myklebust@netapp.com>
We're presently running lock_kernel() under fs_lock via nfs's ->permission
handler. That's a ranking bug and sometimes a sleep-in-spinlock bug. This
problem was introduced in the openat() patchset.
We should not need to hold the current->fs->lock for a codepath that doesn't
use current->fs.
[vsu@altlinux.ru: fix error path]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Al Viro <viro@ftp.linux.org.uk>
Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
As announced, lookup_hash() can now become static.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In order to be able to trigger a mount using the follow_link inode method the
nameidata struct that is passed in needs to have the vfsmount of the autofs
trigger not its parent.
During a path walk if an autofs trigger is mounted on a dentry, when the
follow_link method is called, the nameidata struct contains the vfsmount and
mountpoint dentry of the parent mount while the dentry that is passed in is
the root of the autofs trigger mount. I believe it is impossible to get the
vfsmount of the trigger mount, within the follow_link method, when only the
parent vfsmount and the root dentry of the trigger mount are known.
This patch updates the nameidata struct on entry to __do_follow_link if it
detects that it is out of date. It moves the path_to_nameidata to above
__do_follow_link to facilitate calling it from there. The dput_path is moved
as well as that seemed sensible. No changes are made to these two functions.
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* 'audit.b3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current: (22 commits)
[PATCH] fix audit_init failure path
[PATCH] EXPORT_SYMBOL patch for audit_log, audit_log_start, audit_log_end and audit_format
[PATCH] sem2mutex: audit_netlink_sem
[PATCH] simplify audit_free() locking
[PATCH] Fix audit operators
[PATCH] promiscuous mode
[PATCH] Add tty to syscall audit records
[PATCH] add/remove rule update
[PATCH] audit string fields interface + consumer
[PATCH] SE Linux audit events
[PATCH] Minor cosmetic cleanups to the code moved into auditfilter.c
[PATCH] Fix audit record filtering with !CONFIG_AUDITSYSCALL
[PATCH] Fix IA64 success/failure indication in syscall auditing.
[PATCH] Miscellaneous bug and warning fixes
[PATCH] Capture selinux subject/object context information.
[PATCH] Exclude messages by message type
[PATCH] Collect more inode information during syscall processing.
[PATCH] Pass dentry, not just name, in fsnotify creation hooks.
[PATCH] Define new range of userspace messages.
[PATCH] Filter rule comparators
...
Fixed trivial conflict in security/selinux/hooks.c
As prepare_write, commit_write and readpage are allowed to return
AOP_TRUNCATE_PAGE, page_symlink should respond to them.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It seems there is error check missing in open_namei for errors returned
through intent.open.file (from lookup_instantiate_filp).
If there is plain open performed, then such a check done inside
__path_lookup_intent_open called from path_lookup_open(), but when the open
is performed with O_CREAT flag set, then __path_lookup_intent_open is only
called with LOOKUP_PARENT set where no file opening can occur yet.
Later on lookup_hash is called where exact opening might take place and
intent.open.file may be filled. If it is filled with error value of some
sort, then we get kernel attempting to dereference this error value as
address (and corresponding oops) in nameidata_to_filp() called from
filp_open().
While this is relatively simple to workaround in ->lookup() method by just
checking lookup_instantiate_filp() return value and returning error as
needed, this is not so easy in ->d_revalidate(), where we can only return
"yes, dentry is valid" or "no, dentry is invalid, perform full lookup
again", and just returning 0 on error would cause extra lookup (with
potential extra costly RPCs).
So in short, I believe that there should be no difference in error handling
for opening a file and creating a file in open_namei() and propose this
simple patch as a solution.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Semaphore to mutex conversion.
The conversion was generated via scripts, and the result was validated
automatically via a script as well.
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch augments the collection of inode info during syscall
processing. It represents part of the functionality that was provided
by the auditfs patch included in RHEL4.
Specifically, it:
- Collects information for target inodes created or removed during
syscalls. Previous code only collects information for the target
inode's parent.
- Adds the audit_inode() hook to syscalls that operate on a file
descriptor (e.g. fchown), enabling audit to do inode filtering for
these calls.
- Modifies filtering code to check audit context for either an inode #
or a parent inode # matching a given rule.
- Modifies logging to provide inode # for both parent and child.
- Protect debug info from NULL audit_names.name.
[AV: folded a later typo fix from the same author]
Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The audit hooks (to be added shortly) will want to see dentry->d_inode
too, not just the name.
Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
This patch fixes illegal __GFP_FS allocation inside ext3 transaction in
ext3_symlink(). Such allocation may re-enter ext3 code from
try_to_free_pages. But JBD/ext3 code keeps a pointer to current journal
handle in task_struct and, hence, is not reentrable.
This bug led to "Assertion failure in journal_dirty_metadata()" messages.
http://bugzilla.openvz.org/show_bug.cgi?id=115
Signed-off-by: Andrey Savochkin <saw@saw.sw.com.sg>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I'm currently at the POSIX meeting and one thing covered was the
incompatibility of Linux's link() with the POSIX definition. The name.
Linux does not follow symlinks, POSIX requires it does.
Even if somebody thinks this is a good default behavior we cannot change this
because it would break the ABI. But the fact remains that some application
might want this behavior.
We have one chance to help implementing this without breaking the behavior.
For this we could use the new linkat interface which would need a new
flags parameter. If the new parameter is AT_SYMLINK_FOLLOW the new
behavior could be invoked.
I do not want to introduce such a patch now. But we could add the
parameter now, just don't use it. The patch below would do this. Can we
get this late patch applied before the release more or less fixes the
syscall API?
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix do_path_lookup() to avoid accessing invalid dentry or inode when the
link_path_walk() has failed. This should fix Bugme #5897.
Signed-off-by: Suzuki K P <suzuki@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When walking a path, the LOOKUP_CONTINUE flag is used by some filesystems
(for instance NFS) in order to determine whether or not it is looking up
the last component of the path. It this is the case, it may have to look
at the intent information in order to perform various tasks such as atomic
open.
A problem currently occurs when link_path_walk() hits a symlink. In this
case LOOKUP_CONTINUE may be cleared prematurely when we hit the end of the
path passed by __vfs_follow_link() (i.e. the end of the symlink path)
rather than when we hit the end of the path passed by the user.
The solution is to have link_path_walk() clear LOOKUP_CONTINUE if and only
if that flag was unset when we entered the function.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Update some parameter descriptions to actually match the code.
Signed-off-by: Martin Waitz <tali@admingilde.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Here is a series of patches which introduce in total 13 new system calls
which take a file descriptor/filename pair instead of a single file
name. These functions, openat etc, have been discussed on numerous
occasions. They are needed to implement race-free filesystem traversal,
they are necessary to implement a virtual per-thread current working
directory (think multi-threaded backup software), etc.
We have in glibc today implementations of the interfaces which use the
/proc/self/fd magic. But this code is rather expensive. Here are some
results (similar to what Jim Meyering posted before).
The test creates a deep directory hierarchy on a tmpfs filesystem. Then
rm -fr is used to remove all directories. Without syscall support I get
this:
real 0m31.921s
user 0m0.688s
sys 0m31.234s
With syscall support the results are much better:
real 0m20.699s
user 0m0.536s
sys 0m20.149s
The interfaces are for obvious reasons currently not much used. But they'll
be used. coreutils (and Jeff's posixutils) are already using them.
Furthermore, code like ftw/fts in libc (maybe even glob) will also start using
them. I expect a patch to make follow soon. Every program which is walking
the filesystem tree will benefit.
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ftp.linux.org.uk>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Mark a few VFS functions as mandatory inline (based on Al Viro's request);
these must be inline due to stack usage issues during a recursive loop that
happens during the recursive symlink resolution (symlink to a symlink to a
symlink ..)
This patch at this point does not change behavior and is for documentation
purposes only (but this changes later in the series)
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove the "inline" keyword from a bunch of big functions in the kernel with
the goal of shrinking it by 30kb to 40kb
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
fs: Use <linux/capability.h> where capable() is used.
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch converts the inode semaphore to a mutex. I have tested it on
XFS and compiled as much as one can consider on an ia64. Anyway your
luck with it might be different.
Modified-by: Ingo Molnar <mingo@elte.hu>
(finished the conversion)
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
SUS requires that when truncating a file to the size that it currently
is:
truncate and ftruncate should NOT modify ctime or mtime
O_TRUNC SHOULD modify ctime and mtime.
Currently mtime and ctime are always modified on most local
filesystems (side effect of ->truncate) or never modified (on NFS).
With this patch:
ATTR_CTIME|ATTR_MTIME are sent with ATTR_SIZE precisely when
an update of these times is required whether size changes or not
(via a new argument to do_truncate). This allows NFS to do
the right thing for O_TRUNC.
inode_setattr nolonger forces ATTR_MTIME|ATTR_CTIME when the ATTR_SIZE
sets the size to it's current value. This allows local filesystems
to do the right thing for f?truncate.
Also, the logic in inode_setattr is changed a bit so there are two return
points. One returns the error from vmtruncate if it failed, the other
returns 0 (there can be no other failure).
Finally, if vmtruncate succeeds, and ATTR_SIZE is the only change
requested, we now fall-through and mark_inode_dirty. If a filesystem did
not have a ->truncate function, then vmtruncate will have changed i_size,
without marking the inode as 'dirty', and I think this is wrong.
Signed-off-by: Neil Brown <neilb@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch makes the needlessly global function path_lookup_create()
static.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
->permission and ->lookup have a struct nameidata * argument these days to
pass down lookup intents. Unfortunately some callers of lookup_hash don't
actually pass this one down. For lookup_one_len() we don't have a struct
nameidata to pass down, but as this function is a library function only
used by filesystem code this is an acceptable limitation. All other
callers should pass down the nameidata, so this patch changes the
lookup_hash interface to only take a struct nameidata argument and derives
the other two arguments to __lookup_hash from it. All callers already have
the nameidata argument available so this is not a problem.
At the same time I'd like to deprecate the lookup_hash interface as there
are better exported interfaces for filesystem usage. Before it can
actually be removed I need to fix up rpc_pipefs.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Al Viro <viro@ftp.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A few more callers of permission() just want to check for a different access
pattern on an already open file. This patch adds a wrapper for permission()
that takes a file in preparation of per-mount read-only support and to clean
up the callers a little. The helper is not intended for new code, everything
without the interface set in stone should use vfs_permission()
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Most permission() calls have a struct nameidata * available. This helper
takes that as an argument and thus makes sure we pass it down for lookup
intents and prepares for per-mount read-only support where we need a struct
vfsmount for checking whether a file is writeable.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch extends the iattr structure with a file pointer memeber, and adds
an ATTR_FILE validity flag for this member.
This is set if do_truncate() is invoked from ftruncate() or from
do_coredump().
The change is source and binary compatible.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
lookup_flags() is only called from the non-create case, so it needn't check
for O_CREAT|O_EXCL.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This will allow nfs_permission() to perform additional optimizations when
walking the path, by folding the ACCESS(MAY_EXEC) call on the directory
into the lookup revalidation.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This is needed by NFSv4 for atomicity reasons: our open command is in
fact a lookup+open, so we need to be able to propagate open context
information from lookup() into the resulting struct file's
private_data field.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The nameidata "last.name" is always allocated with "__getname()", and
should always be free'd with "__putname()".
Using "putname()" without the underscores will leak memory, because the
allocation will have been hidden from the AUDITSYSCALL code.
Arguably the real bug is that the AUDITSYSCALL code is really broken,
but in the meantime this fixes the problem people see.
Reported by Robert Derr, patch by Rick Lindsley.
Acked-by: Al Viro <viro@ftp.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch removes the inode_post_link and inode_post_rename LSM hooks as
they are unused (and likely useless).
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch removes the inode_post_create/mkdir/mknod/symlink LSM hooks as
they are obsoleted by the new inode_init_security hook that enables atomic
inode security labeling.
If anyone sees any reason to retain these hooks, please speak now. Also,
is anyone using the post_rename/link hooks; if not, those could also be
removed.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Extract common code into inline functions to make reading easier.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This bug could cause oopses and page state corruption, because ncpfs
used the generic page-cache symlink handlign functions. But those
functions only work if the page cache is guaranteed to be "stable", ie a
page that was installed when the symlink walk was started has to still
be installed in the page cache at the end of the walk.
We could have fixed ncpfs to not use the generic helper routines, but it
is in many ways much cleaner to instead improve on the symlink walking
helper routines so that they don't require that absolute stability.
We do this by allowing "follow_link()" to return a error-pointer as a
cookie, which is fed back to the cleanup "put_link()" routine. This
also simplifies NFS symlink handling.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This adds a MOVE_SELF event to inotify. It is sent whenever the inode
you are watching is moved. We need this event so that we can catch
something like this:
- app1:
watch /etc/mtab
- app2:
cp /etc/mtab /tmp/mtab-work
mv /etc/mtab /etc/mtab~
mv /tmp/mtab-work /etc/mtab
app1 still thinks it's watching /etc/mtab but it's actually watching
/etc/mtab~.
Signed-off-by: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: Robert Love <rml@novell.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The patch below unhooks fsnotify from vfs_unlink & vfs_rmdir. It
introduces two new fsnotify calls, that are hooked in at the dcache
level. This not only more closely matches how the VFS layer works, it
also avoids the problem with locking and inode lifetimes.
The two functions are
- fsnotify_nameremove -- called when a directory entry is going away.
It notifies the PARENT of the deletion. This is called from
d_delete().
- inoderemove -- called when the files inode itself is going away. It
notifies the inode that is being deleted. This is called from
dentry_iput().
Signed-off-by: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This avoids the whole #ifdef mess by just getting a copy of
dentry->d_inode before d_delete is called - that makes the codepaths the
same for the INOTIFY/DNOTIFY cases as for the regular no-notify case.
I've been running this under a Gnome session for the last 10 minutes.
Inotify is being used extensively.
Signed-off-by: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The included patch fixes a problem where a inotify client would receive a
delete event before the file was actually deleted. The bug affects both
dnotify & inotify.
Signed-off-by: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: Robert Love <rml@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When a file is moved over an existing file that you are watching,
inotify won't send you a DELETE_SELF event and it won't unref the inode
until the inotify instance is closed by the application.
Signed-off-by: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: Robert Love <rml@novell.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
inotify is intended to correct the deficiencies of dnotify, particularly
its inability to scale and its terrible user interface:
* dnotify requires the opening of one fd per each directory
that you intend to watch. This quickly results in too many
open files and pins removable media, preventing unmount.
* dnotify is directory-based. You only learn about changes to
directories. Sure, a change to a file in a directory affects
the directory, but you are then forced to keep a cache of
stat structures.
* dnotify's interface to user-space is awful. Signals?
inotify provides a more usable, simple, powerful solution to file change
notification:
* inotify's interface is a system call that returns a fd, not SIGIO.
You get a single fd, which is select()-able.
* inotify has an event that says "the filesystem that the item
you were watching is on was unmounted."
* inotify can watch directories or files.
Inotify is currently used by Beagle (a desktop search infrastructure),
Gamin (a FAM replacement), and other projects.
See Documentation/filesystems/inotify.txt.
Signed-off-by: Robert Love <rml@novell.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Heiko Carstens