f2fs: disallow switch extent_cache option dynamically
f2fs: disallow switch extent_cache option dynamically

Swith extent_cache option dynamically when remount may casue consistency
issue between extent cache and dnode page. Fix in this patch to avoid
that condition.

Signed-off-by: Chao Yu <0cc5db7488e13b393f245aa6263acec5e92fdcc5@samsung.com>
Signed-off-by: Jaegeuk Kim <71255387a32c360dfbe6dfb7aaeb123bf1dc8cb6@kernel.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs