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2006-02-01[PATCH] fuse: fix async read for legacy filesystemsMiklos Szeredi3-4/+22
While asynchronous reads mean a performance improvement in most cases, if the filesystem assumed that reads are synchronous, then async reads may degrade performance (filesystem may receive reads out of order, which can confuse it's own readahead logic). With sshfs a 1.5 to 4 times slowdown can be measured. There's also a need for userspace filesystems to know whether asynchronous reads are supported by the kernel or not. To achive these, negotiate in the INIT request whether async reads will be used and the maximum readahead value. Update interface version to 7.6 If userspace uses a version earlier than 7.6, then disable async reads, and set maximum readahead value to the maximum read size, as done in previous versions. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: fix bitfield raceMiklos Szeredi2-3/+23
Fix race in setting bitfields of fuse_conn. Spotted by Andrew Morton. The two fields ->connected and ->mounted were always changed with the fuse_lock held. But other bitfields in the same structure were changed without the lock. In theory this could lead to losing the assignment of even the ones under lock. The chosen solution is to change these two fields to be a full unsigned type. The other bitfields aren't "important" enough to warrant the extra complexity of full locking or changing them to bitops. For all bitfields document why they are safe wrt. concurrent assignments. Also make the initialization of the 'num_waiting' atomic counter explicit. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: use asynchronous READ requests for readpagesMiklos Szeredi1-17/+27
This patch changes fuse_readpages() to send READ requests asynchronously. This makes it possible for userspace filesystems to utilize the kernel readahead logic instead of having to implement their own (resulting in double caching). Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: READ request initializationMiklos Szeredi3-24/+18
Add a separate function for filling in the READ request. This will make it possible to send asynchronous READ requests as well as synchronous ones. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: move INIT handling to inode.cMiklos Szeredi3-50/+45
Now the INIT requests can be completely handled in inode.c and the fuse_send_init() function need not be global any more. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: add asynchronous request supportMiklos Szeredi3-14/+43
Add possibility for requests to run asynchronously and call an 'end' callback when finished. With this, the special handling of the INIT and RELEASE requests can be cleaned up too. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: add connection abortingMiklos Szeredi3-6/+88
Add ability to abort a filesystem connection. With the introduction of asynchronous reads, the ability to interrupt any request is not enough to dissolve deadlocks, since now waiting for the request completion (page unlocked) is independent of the actual request, so in a deadlock all threads will be uninterruptible. The solution is to make it possible to abort all requests, even those currently undergoing I/O to/from userspace. The natural interface for this is 'mount -f mountpoint', but that only works as long as the filesystem is attached. So also add an 'abort' attribute to the sysfs view of the connection. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: add number of waiting requests attributeMiklos Szeredi3-3/+21
This patch adds the 'waiting' attribute which indicates how many filesystem requests are currently waiting to be completed. A non-zero value without any filesystem activity indicates a hung or deadlocked filesystem. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: make fuse connection a kobjectMiklos Szeredi3-43/+164
Kobjectify fuse_conn, and make it visible under /sys/fs/fuse/connections. Lacking any natural naming, connections are numbered. This patch doesn't add any attributes, just the infrastructure. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: extend semantics of connected flagMiklos Szeredi3-4/+6
The ->connected flag for a fuse_conn object previously only indicated whether the device file for this connection is currently open or not. Change it's meaning so that it indicates whether the connection is active or not: now either umount or device release will clear the flag. The separate ->mounted flag is still needed for handling background requests. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: introduce list for requests under I/OMiklos Szeredi3-6/+10
Create a new list for requests in the process of being transfered to/from userspace. This will be needed to be able to abort all requests even those currently under I/O Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: introduce unified request stateMiklos Szeredi2-11/+19
The state of request was made up of 2 bitfields (->sent and ->finished) and of the fact that the request was on a list or not. Unify this into a single state field. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: miscellaneous cleanupMiklos Szeredi3-15/+6
- remove some unneeded assignments - use kzalloc instead of kmalloc + memset - simplify setting sb->s_fs_info - in fuse_send_init() use fuse_get_request() instead of do_get_request() helper Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: uninline some functionsMiklos Szeredi3-21/+17
Inline keyword is unnecessary in most cases. Clean them up. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: handle error INIT replyMiklos Szeredi1-1/+1
Handle the case when the INIT request is answered with an error. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: fix request_end()Miklos Szeredi1-11/+7
This function used the request object after decrementing its reference count and releasing the lock. This could in theory lead to all sorts of problems. Fix and simplify at the same time. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16[PATCH] fuse: fuse_copy_finish() order fixMiklos Szeredi1-1/+3
fuse_copy_finish() must be called before request_end(), since the later might sleep, and no sleeping is allowed between fuse_copy_one() and fuse_copy_finish() because of kmap_atomic()/kunmap_atomic() used in them. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-09[PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_semJes Sorensen1-2/+2
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>
2006-01-06[PATCH] fuse: check file type in lookupMiklos Szeredi2-13/+22
Previously invalid types were quietly changed to regular files, but at revalidation the inode was changed to bad. This was rather inconsistent behavior. Now check if the type is valid on initial lookup, and return -EIO if not. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06[PATCH] fuse: ensure progress in read and writeMiklos Szeredi1-4/+3
In direct_io mode, send at least one page per reqest. Previously it was possible that reqests with zero data were sent, and hence the read/write didn't make any progress, resulting in an infinite (though interruptible) loop. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06[PATCH] fuse: make maximum write data configurableMiklos Szeredi3-23/+32
Make the maximum size of write data configurable by the filesystem. The previous fixed 4096 limit only worked on architectures where the page size is less or equal to this. This change make writing work on other architectures too, and also lets the filesystem receive bigger write requests in direct_io mode. Normal writes which go through the page cache are still limited to a page sized chunk per request. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06[PATCH] fuse: clean up request size limit checkingMiklos Szeredi4-27/+24
Change the way a too large request is handled. Until now in this case the device read returned -EINVAL and the operation returned -EIO. Make it more flexibible by not returning -EINVAL from the read, but restarting it instead. Also remove the fixed limit on setxattr data and let the filesystem provide as large a read buffer as it needs to handle the extended attribute data. The symbolic link length is already checked by VFS to be less than PATH_MAX, so the extra check against FUSE_SYMLINK_MAX is not needed. The check in fuse_create_open() against FUSE_NAME_MAX is not needed, since the dentry has already been looked up, and hence the name already checked. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06[PATCH] fuse: fail file operations on bad inodeMiklos Szeredi2-5/+37
Make file operations on a bad inode fail. This just makes things a bit more consistent. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06[PATCH] fuse: add code documentationMiklos Szeredi1-9/+90
Document some not-so-trivial functions. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06[PATCH] fuse: support caching negative dentriesMiklos Szeredi1-21/+43
Add support for caching negative dentries. Up till now, ->d_revalidate() always forced a new lookup on these. Now let the lookup method return a zero node ID (not used for anything else) meaning a negative entry, but with a positive cache timeout. The old way of signaling negative entry (replying ENOENT) still works. Userspace should check the ABI minor version to see whether sending a zero ID is allowed by the kernel or not. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06[PATCH] fuse: add frsize to statfs replyMiklos Szeredi1-1/+4
Add 'frsize' member to the statfs reply. I'm not sure if sending f_fsid will ever be needed, but just in case leave some space at the end of the structure, so less compatibility mess would be required. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06[PATCH] fuse: bump interface versionMiklos Szeredi2-0/+5
Change interface version to 7.4. Following changes will need backward compatibility support, so store the minor version returned by userspace. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06[PATCH] fuse: clean up page offset calculationMiklos Szeredi1-4/+3
Use page_offset() instead of doing page offset calculation by hand. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06[PATCH] fuse: clean up fuse_lookup()Miklos Szeredi1-52/+23
Simplify fuse_lookup() and related functions. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-28[PATCH] fuse: check for invalid node ID in fuse_create_open()Miklos Szeredi1-3/+8
Check for invalid node ID values in the new atomic create+open method. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-28[PATCH] fuse: check directory aliasing in mkdirMiklos Szeredi1-9/+17
Check the created directory inode for aliases in the mkdir() method. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07[PATCH] FUSE: pass file handle in setattrMiklos Szeredi1-14/+14
This patch passes the file handle supplied in iattr to userspace, in case the ->setattr() was invoked from sys_ftruncate(). This solves the permission checking (or lack thereof) in ftruncate() for the class of filesystems served by an unprivileged userspace process. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07[PATCH] FUSE: atomic create+openMiklos Szeredi4-48/+211
This patch adds an atomic create+open operation. This does not yet work if the file type changes between lookup and create+open, but solves the permission checking problems for the separte create and open methods. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07[PATCH] FUSE: add access callMiklos Szeredi2-0/+38
Add a new access call, which will only be called if ->permission is invoked from sys_access(). In all other cases permission checking is delayed until the actual filesystem operation. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07[PATCH] fuse: remove dead code from fuse_permissionChristoph Hellwig1-3/+0
The -EROFS check has moved up to permission() in the VFS a while ago. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30[PATCH] fuse: spelling fixesMiklos Szeredi2-9/+9
Correct some typos and inconsistent use of "initialise" vs "initialize" in comments. Reported by Ioannis Barkas. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30[PATCH] fuse: clean up dead code related to nfs exportingMiklos Szeredi1-2/+3
Remove last remains of NFS exportability support. The code is actually buggy (as reported by Akshat Aranya), since 'alias' will be leaked if it's non-null and alias->d_flags has DCACHE_DISCONNECTED. This is not an active bug, since there will never be any disconnected dentries. But it's better to get rid of the unnecessary complexity anyway. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-30[PATCH] fuse: check O_DIRECTMiklos Szeredi1-0/+4
Check O_DIRECT and return -EINVAL error in open. dentry_open() also checks this but only after the open method is called. This patch optimizes away the unnecessary upcalls in this case. It could be a correctness issue too: if filesystem has open() with side effect, then it should fail before doing the open, not after. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-28[PATCH] fuse: check reserved node ID valuesMiklos Szeredi1-0/+6
This patch checks reserved node ID values returned by lookup and creation operations. In case one of the reserved values is sent, return -EIO. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] FUSE: don't allow restarting of system callsMiklos Szeredi5-111/+45
This patch removes ability to interrupt and restart operations while there hasn't been any side-effect. The reason: applications. There are some apps it seems that generate signals at a fast rate. This means, that if the operation cannot make enough progress between two signals, it will be restarted for ever. This bug actually manifested itself with 'krusader' trying to open a file for writing under sshfs. Thanks to Eduard Czimbalmos for the report. The problem can be solved just by making open() uninterruptible, because in this case it was the truncate operation that slowed down the progress. But it's better to solve this by simply not allowing interrupts at all (except SIGKILL), because applications don't expect file operations to be interruptible anyway. As an added bonus the code is simplified somewhat. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] FUSE: add fsync operation for directoriesMiklos Szeredi3-4/+29
This patch adds a new FSYNCDIR request, which is sent when fsync is called on directories. This operation is available in libfuse 2.3-pre1 or greater. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] fuse: don't update file timesMiklos Szeredi3-4/+9
Don't change mtime/ctime/atime to local time on read/write. Rather invalidate file attributes, so next stat() will force a GETATTR call. Bug reported by Ben Grimm. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] fuse: more flexible cachingMiklos Szeredi3-32/+8
Make data caching behavior selectable on a per-open basis instead of per-mount. Compatibility for the old mount options 'kernel_cache' and 'direct_io' is retained in the userspace library (version 2.4.0-pre1 or later). Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] fuse: transfer readdir data through deviceMiklos Szeredi4-84/+69
This patch removes a long lasting "hack" in FUSE, which used a separate channel (a file descriptor refering to a disk-file) to transfer directory contents from userspace to the kernel. The patch adds three new operations (OPENDIR, READDIR, RELEASEDIR), which have semantics and implementation exactly maching the respective file operations (OPEN, READ, RELEASE). This simplifies the directory reading code. Also disk space is not necessary, which can be important in embedded systems. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] FUSE - direct I/OMiklos Szeredi3-2/+146
This patch adds support for the "direct_io" mount option of FUSE. When this mount option is specified, the page cache is bypassed for read and write operations. This is useful for example, if the filesystem doesn't know the size of files before reading them, or when any kind of caching is harmful. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] fuse: stricter mount option checkingMiklos Szeredi1-2/+11
Check for the presence of all mandatory mount options. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] FUSE: tighten check for processes allowed accessMiklos Szeredi3-6/+49
This patch tightens the check for allowing processes to access non-privileged mounts. The rational is that the filesystem implementation can control the behavior or get otherwise unavailable information of the filesystem user. If the filesystem user process has the same uid, gid, and is not suid or sgid application, then access is safe. Otherwise access is not allowed unless the "allow_other" mount option is given (for which policy is controlled by the userspace mount utility). Thanks to everyone linux-fsdevel, especially Martin Mares who helped uncover problems with the previous approach. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] FUSE - readpages operationMiklos Szeredi3-0/+85
This patch adds readpages support to FUSE. With the help of the readpages() operation multiple reads are bundled together and sent as a single request to userspace. This can improve reading performace. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] FUSE - extended attribute operationsMiklos Szeredi2-0/+195
This patch adds the extended attribute operations to FUSE. The following operations are added: o getxattr o setxattr o listxattr o removexattr Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] FUSE - mount optionsMiklos Szeredi5-67/+170
This patch adds miscellaneous mount options to the FUSE filesystem. The following mount options are added: o default_permissions: check permissions with generic_permission() o allow_other: allow other users to access files o allow_root: allow root to access files o kernel_cache: don't invalidate page cache on open Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>