| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Wed, 29 Apr 2009 12:02:46 +0200 From: Jan Kara <jack@...e.cz> To: linux-ext4@...r.kernel.org Cc: linux-fsdevel@...r.kernel.org, npiggin@...e.de Subject: [PATCH 0/4] Make page_mkwrite() more useful for blocksize < pagesize Hi, this is a next version of my patches which implement VFS helpers so that page_mkwrite() is reliably called at the first write access to a page after the amount of blocks allocated under the page could change. This solves the problem with filesystems dropping data on the floor when they hit ENOSPC (or EDQUOT) during writepage(). The series also contains patches for ext[2-4] showing how the VFS framework can be used. This is probably not the final version of the patches since I did some performance measurements with ext3 and allocating blocks on page-fault time instead of at writepage() time has a significant cost - BerkelyDB based workloads are slower by ~10% because of much higher file fragmentation (essentially allocation at writepage time had a kind of delayed allocation effect for us and it helped a lot in these random write scenarios). I'm thinking how to solve this so that any filesystem wanting reliable mmap and reasonable performance behaviour doesn't have to implement something like delayed allocation or other workaround again... Honza -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists