* i_version_1_vfs_layer @ 2007-02-15 8:26 Andrew Morton 2007-02-16 16:00 ` i_version_1_vfs_layer Cordenner jean noel 0 siblings, 1 reply; 2+ messages in thread From: Andrew Morton @ 2007-02-15 8:26 UTC (permalink / raw) To: Jean Noel Cordenner, Theodore Ts'o; +Cc: linux-ext4@vger.kernel.org This: ftp://ftp.kernel.org/pub/linux/kernel/people/tytso/ext4-patches/2.6.20-ext4-1/broken-out/i_version_1_vfs_layer significantly deoptimises file_update_time() for major filesystems (eg, ext3). The changelog offers no reason for this alteration. In fact the changelog basically says nothing at all and needs a lot of work. What is this patch doing and why does it need to make that change? ^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: i_version_1_vfs_layer 2007-02-15 8:26 i_version_1_vfs_layer Andrew Morton @ 2007-02-16 16:00 ` Cordenner jean noel 0 siblings, 0 replies; 2+ messages in thread From: Cordenner jean noel @ 2007-02-16 16:00 UTC (permalink / raw) To: Andrew Morton; +Cc: Theodore Ts'o, linux-ext4@vger.kernel.org Andrew Morton a écrit : > This: > > ftp://ftp.kernel.org/pub/linux/kernel/people/tytso/ext4-patches/2.6.20-ext4-1/broken-out/i_version_1_vfs_layer > > significantly deoptimises file_update_time() for major filesystems (eg, ext3). > > The changelog offers no reason for this alteration. In fact the changelog > basically says nothing at all and needs a lot of work. > > What is this patch doing and why does it need to make that change? > Actually, this set of patches are still in progress. I recently profile them. It shows that the CPU usage is really huge, so it has to be improved. The i_version field is a counter that is set on every inode creation and that is incremented every time the inode data is modified (similarly to the "ctime" time-stamp). The aim is to fulfill NFSv4 requirements for rfc3530. For the moment, the counter is only a 32bit value but it is planned to be 64bit as required. The patch is divided into 3 parts, the vfs layer, the ext4 specific code and an user part to check i_version changes via stat. (cf http://permalink.gmane.org/gmane.comp.file-systems.ext4/923) ^ permalink raw reply [flat|nested] 2+ messages in thread
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