| Anton Altaparmakov | Re: punching holes in files
Don't know about SMB/CIFS but on Windows locally you would need to
first set the file sparse, and then to punch the hole. These two
things are accomplished like so on Windows (STARTING_OFFSET is the
first byte of the hole to be punched and END_OFFSET is the first byte
after the hole to be punched):
HANDLE f; // This is obtained from a CreateFile() call...
DWORD bw;
/* Set file sparse. */
if (!DeviceIoControl(f, FSCTL_SET_SPARSE, NULL, 0, NULL, 0, &bw,
NULL)) {
// ...
| Nov 1, 4:17 pm 2007 |
| Steve French | punching holes in files
madvise_remove (in Linux) is used to free the backing store associated
with pages (punching a hole in a file). This is one of the vfs
operations that we do not send over the wire to Samba (so this call
would return -ENOSYS locally). Any thoughts on whether this could be
done with an obscure SetFileInfo level or FCNTL or whether it is worth
adding to the CIFS POSIX Extensions?
A second interesting question is whether to implement fallocate over
the wire. sys_fallocate takes a range (and ...
| Nov 1, 12:16 pm 2007 |
| Jeff Layton | Re: No longer set S_ISVTX when mounted to Windows
On Thu, 1 Nov 2007 11:08:33 -0500
ACK :-)
Looks pretty much like the patch I sent to the list on Oct 16. At the
time I think you emailed JRA to ask why we were setting the sticky bit
but I don't believe he ever replied.
AFAICT, the sticky bit on a regular file doesn't mean anything on
Linux. Having it set is harmless, but I could see problems if someone
were for instance, to tar up some files on a CIFS share and untar them
on an OS where it does have meaning.
--
Jeff Layton ...
| Nov 1, 1:00 pm 2007 |
| Steve French | No longer set S_ISVTX when mounted to Windows
Not sure why the cifs code sets the S_ISVTX bit when mounted to
Windows servers. I think the intent was to turn off all of the high
bits except that (S_ISGID) needed to indicate mandatory locking
(mandatory locking is set by having S_ISGID on and group execute,
S_IXGRP, off). When reviewing the cifsacl code (to map
CIFS/Windows/NTFS ACLs to mode bits I noticed that we were setting the
sticky bit (S_ISVTX) on files (this does not happen when a user
specifies a default mode on mount) and probably ...
| Nov 1, 9:08 am 2007 |
| Serge E. Hallyn |
| Nov 1, 3:43 pm 2007 |
| James Morris |
| Nov 1, 1:58 pm 2007 |
| James Morris |
| Nov 1, 1:58 pm 2007 |
| Serge E. Hallyn |
| Nov 1, 3:47 pm 2007 |
| David P. Quigley | [PATCH 1/2] VFS/Security: Rework inode_getsecurity and c ...
This patch modifies the interface to inode_getsecurity to have the function
return a buffer containing the security blob and its length via parameters
instead of relying on the calling function to give it an appropriately sized
buffer. Security blobs obtained with this function should be freed using the
release_secctx LSM hook. This alleviates the problem of the caller having to
guess a length and preallocate a buffer for this function allowing it to be
used elsewhere for Labeled NFS. The patch ...
| Nov 1, 7:40 am 2007 |
| David P. Quigley | [PATCH 0/2] getsecurity/vfs_getxattr cleanup V2
This patch series addresses two concerns. Currently when a developer
wishes to obtain a security blob from the LSM he/she has to guess at the
length of the blob being returned. We modify security_inode_getsecurity
to return an appropriately sized buffer populated with the security
information and the length of that buffer. This is similar to the
approach taken by Al Viro for the security_getprocattr hook.
The second concern that this patch set addresses is that vfs_getxattr
reads the security ...
| Nov 1, 7:35 am 2007 |
| David P. Quigley | [PATCH 2/2] VFS: Reorder vfs_getxattr to avoid unnecessa ...
Originally vfs_getxattr would pull the security xattr variable using
the inode getxattr handle and then proceed to clobber it with a subsequent call
to the LSM. This patch reorders the two operations such that when the xattr
requested is in the security namespace it first attempts to grab the value from
the LSM directly. If it fails to obtain the value because there is no module
present or the module does not support the operation it will fall back to using
the inode getxattr operation. In the ...
| Nov 1, 7:41 am 2007 |
| addy soft | using pgmeter for benchmarking
hello all,
I am a newbie in filesystem field and wanted to benchmark filesystem
using pgmeter.
But the source that i have downloaded from
http://pgmeter.sourceforge.net/ CVS seems to be too old and have a
kernel patch with it which is for kernel 2.2.6.
There is a syscall implemented with that version of pgmeter which is
used to flush the page cache for a particular file.
Has anyone used pgmeter to work with kernel 2.6?
I want to use pgmeter for kernel 2.6.18.
Is there pgmeter for ...
| Nov 1, 3:45 am 2007 |
| Avishay Traeger | Re: using pgmeter for benchmarking
Since 2.6.16 there has been a drop_caches proc file. Instead of porting
this system call, I think you could modify pgmeter to use this. Here
are some details:
===============================================
Writing to this will cause the kernel to drop clean caches, dentries and
inodes from memory, causing that memory to become free.
To free pagecache:
* echo 1 > /proc/sys/vm/drop_caches
To free dentries and inodes:
* echo 2 > /proc/sys/vm/drop_caches
To free pagecache, ...
| Nov 1, 7:06 am 2007 |
| Badari Pulavarty | Re: migratepage failures on reiserfs
Unfortunately, these buffer pages are spread all around making
those sections of memory non-removable. Of course, one can use
ZONE_MOVABLE to make sure to guarantee the remove. But I am
hoping we could easily group all these allocations and minimize
spreading them around. Mel ?
Thanks,
Badari
-
| Nov 1, 11:10 am 2007 |
| Badari Pulavarty | Re: migratepage failures on reiserfs
Ahhhhhhhhhhhhh !! I am so blind :(
I have been suspecting reiserfs all along, since its executing
fallback_migrate_page(). Actually, these buffer heads are
backing blockdev. I guess these are metadata buffers :(
I am not sure we can do much with these..
Thanks,
Badari
-
| Nov 1, 9:38 am 2007 |
| Chris Mason | Re: migratepage failures on reiserfs
On Thu, 01 Nov 2007 08:38:57 -0800
Hmpf, my first reply had a paragraph about the block device inode
pages, I noticed the phrase file data pages and deleted it ;)
But, for the metadata buffers there's not much we can do. They are
included in a bunch of different lists and the patch would
be non-trivial.
-chris
-
| Nov 1, 8:51 am 2007 |
| Ric Wheeler | Re: [patch 1/1] Drop CAP_SYS_RAWIO requirement for FIBMAP
I don't see how restricting FIBMAP use helps prevent fragmentation since FIBMAP
just allows you to see what damage was already done.
You can create nicely fragmented files simply by having multiple threads writing
concurrently to one or more files in the same directory (depending on the file
system, allocation policy, etc).
ric
-
| Nov 1, 7:51 am 2007 |
| James Morris |
| Oct 31, 8:56 pm 2007 |
