Hi, On Thu, 2014-03-13 at 17:23 +0100, Jan Kara wrote: > On Thu 13-03-14 10:20:56, Ted Tso wrote: > > Previously, the no-op "mount -o mount /dev/xxx" operation when the > ^^remount > > > file system is already mounted read-write causes an implied, > > unconditional syncfs(). This seems pretty stupid, and it's certainly > > documented or guaraunteed to do this, nor is it particularly useful, > > except in the case where the file system was mounted rw and is getting > > remounted read-only. > > > > However, it's possible that there might be some file systems that are > > actually depending on this behavior. In most file systems, it's > > probably fine to only call sync_filesystem() when transitioning from > > read-write to read-only, and there are some file systems where this is > > not needed at all (for example, for a pseudo-filesystem or something > > like romfs). > Hum, I'd avoid this excercise at least for filesystem where > sync_filesystem() is obviously useless - proc, debugfs, pstore, devpts, > also always read-only filesystems such as isofs, qnx4, qnx6, befs, cramfs, > efs, freevxfs, romfs, squashfs. I think you can find a couple more which > clearly don't care about sync_filesystem() if you look a bit closer. > > > Honza
I guess the same is true for other file systems which are mounted ro too. So maybe a check for MS_RDONLY before doing the sync in those cases? Steve. ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. Written by three acclaimed leaders in the field, this first edition is now available. Download your free book today! http://p.sf.net/sfu/13534_NeoTech _______________________________________________ Jfs-discussion mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/jfs-discussion
