Searched +hist:69 +hist:c433ed (Results 1 - 3 of 3) sorted by relevance

/linux-master/fs/ecryptfs/
H A Dmain.cdiff 69c433ed Thu Oct 23 16:14:39 MDT 2014 Miklos Szeredi <mszeredi@suse.cz> fs: limit filesystem stacking depth

Add a simple read-only counter to super_block that indicates how deep this
is in the stack of filesystems. Previously ecryptfs was the only stackable
filesystem and it explicitly disallowed multiple layers of itself.

Overlayfs, however, can be stacked recursively and also may be stacked
on top of ecryptfs or vice versa.

To limit the kernel stack usage we must limit the depth of the
filesystem stack. Initially the limit is set to 2.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff 69c433ed Thu Oct 23 16:14:39 MDT 2014 Miklos Szeredi <mszeredi@suse.cz> fs: limit filesystem stacking depth

Add a simple read-only counter to super_block that indicates how deep this
is in the stack of filesystems. Previously ecryptfs was the only stackable
filesystem and it explicitly disallowed multiple layers of itself.

Overlayfs, however, can be stacked recursively and also may be stacked
on top of ecryptfs or vice versa.

To limit the kernel stack usage we must limit the depth of the
filesystem stack. Initially the limit is set to 2.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
/linux-master/fs/overlayfs/
H A Dsuper.cdiff 69c433ed Thu Oct 23 16:14:39 MDT 2014 Miklos Szeredi <mszeredi@suse.cz> fs: limit filesystem stacking depth

Add a simple read-only counter to super_block that indicates how deep this
is in the stack of filesystems. Previously ecryptfs was the only stackable
filesystem and it explicitly disallowed multiple layers of itself.

Overlayfs, however, can be stacked recursively and also may be stacked
on top of ecryptfs or vice versa.

To limit the kernel stack usage we must limit the depth of the
filesystem stack. Initially the limit is set to 2.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff 69c433ed Thu Oct 23 16:14:39 MDT 2014 Miklos Szeredi <mszeredi@suse.cz> fs: limit filesystem stacking depth

Add a simple read-only counter to super_block that indicates how deep this
is in the stack of filesystems. Previously ecryptfs was the only stackable
filesystem and it explicitly disallowed multiple layers of itself.

Overlayfs, however, can be stacked recursively and also may be stacked
on top of ecryptfs or vice versa.

To limit the kernel stack usage we must limit the depth of the
filesystem stack. Initially the limit is set to 2.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
/linux-master/include/linux/
H A Dfs.hdiff 69df79a4 Mon May 22 07:49:50 MDT 2023 David Howells <dhowells@redhat.com> splice: Rename direct_splice_read() to copy_splice_read()

Rename direct_splice_read() to copy_splice_read() to better reflect as to
what it does.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
cc: Steve French <sfrench@samba.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: linux-cifs@vger.kernel.org
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20230522135018.2742245-4-dhowells@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff 69c433ed Thu Oct 23 16:14:39 MDT 2014 Miklos Szeredi <mszeredi@suse.cz> fs: limit filesystem stacking depth

Add a simple read-only counter to super_block that indicates how deep this
is in the stack of filesystems. Previously ecryptfs was the only stackable
filesystem and it explicitly disallowed multiple layers of itself.

Overlayfs, however, can be stacked recursively and also may be stacked
on top of ecryptfs or vice versa.

To limit the kernel stack usage we must limit the depth of the
filesystem stack. Initially the limit is set to 2.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff 69c433ed Thu Oct 23 16:14:39 MDT 2014 Miklos Szeredi <mszeredi@suse.cz> fs: limit filesystem stacking depth

Add a simple read-only counter to super_block that indicates how deep this
is in the stack of filesystems. Previously ecryptfs was the only stackable
filesystem and it explicitly disallowed multiple layers of itself.

Overlayfs, however, can be stacked recursively and also may be stacked
on top of ecryptfs or vice versa.

To limit the kernel stack usage we must limit the depth of the
filesystem stack. Initially the limit is set to 2.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff 69b45732 Sat May 28 09:25:51 MDT 2011 Andi Kleen <ak@linux.intel.com> Cache xattr security drop check for write v2

Some recent benchmarking on btrfs showed that a major scaling bottleneck
on large systems on btrfs is currently the xattr lookup on every write.

Why xattr lookup on every write I hear you ask?

write wants to drop suid and security related xattrs that could set o
capabilities for executables. To do that it currently looks up
security.capability on EVERY write (even for non executables) to decide
whether to drop it or not.

In btrfs this causes an additional tree walk, hitting some per file system
locks and quite bad scalability. In a simple read workload on a 8S
system I saw over 90% CPU time in spinlocks related to that.

Chris Mason tells me this is also a problem in ext4, where it hits
the global mbcache lock.

This patch adds a simple per inode to avoid this problem. We only
do the lookup once per file and then if there is no xattr cache
the decision. All xattr changes clear the flag.

I also used the same flag to avoid the suid check, although
that one is pretty cheap.

A file system can also set this flag when it creates the inode,
if it has a cheap way to do so. This is done for some common file systems
in followon patches.

With this patch a major part of the lock contention disappears
for btrfs. Some testing on smaller systems didn't show significant
performance changes, but at least it helps the larger systems
and is generally more efficient.

v2: Rename is_sgid. add file system helper.
Cc: chris.mason@oracle.com
Cc: josef@redhat.com
Cc: viro@zeniv.linux.org.uk
Cc: agruen@linbit.com
Cc: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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