[PATCH] tmpfs: time granularity fix for [acm]time going backwards
I noticed a strange behavior in a tmpfs file system the other day, while building packages - occasionally, and seemingly at random, make decided to rebuild a target. However, only on tmpfs. A file would be created, and if checked, it had a sub-second timestamp. However, after an utimes related call where sub-seconds should be set, they were zeroed instead. In the case that a file was created, and utimes(...,NULL) was used on it in the same second, the timestamp on the file moved backwards. After some digging, I found that this was being caused by tmpfs not having a time granularity set, thus inheriting the default 1 second granularity. Hugh adds: yes, we missed tmpfs when the s_time_gran mods went into 2.6.11. Unfortunately, the granularity of CURRENT_TIME, often used in filesystems, does not match the default granularity set by alloc_super. A few more such discrepancies have been found, but this is the most important to fix now. Signed-off-by:Robin H. Johnson <robbat2@gentoo.org> Acked-by:
Andi Kleen <ak@suse.de> Signed-off-by:
Hugh Dickins <hugh@veritas.com> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
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