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. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
