Messages in this thread | | | From | "Takashi Sato" <> | Subject | Re: [RFC] ext3 freeze feature | Date | Fri, 15 Feb 2008 20:51:15 +0900 |
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Hi,
Christoph Hellwig wrote: > On Fri, Feb 08, 2008 at 08:26:57AM -0500, Andreas Dilger wrote: >> You may as well make the common ioctl the same as the XFS version, >> both by number and parameters, so that applications which already >> understand the XFS ioctl will work on other filesystems. > > Yes. In facy you should be able to lift the implementations of > XFS_IOC_FREEZE and XFS_IOC_THAW to generic code, there's nothing > XFS-specific in there.
According to Documentation/ioctl-number.txt, XFS_IOC_XXXs (_IOWR('X', aa, bb)) are defined for XFS like below. From Documentation/ioctl-number.txt: ---------------------------------------------------------------------------- Code Seq# Include File Comments ======================================================== : : 'X' all linux/xfs_fs.h ---------------------------------------------------------------------------- So XFS_IOC_FREEZE and XFS_IOC_THAW cannot be lifted to generic code simply. I think we should create new generic numbers for freeze and thaw like FIBMAP as followings. linux/fs.h: #define FIFREEZE _IO(0x00,3) #define FITHAW _IO(0x00,4)
And xfs_freeze calls XFS_IOC_FREEZE with a magic number 1, but what is 1? Instead, I'd like the sec to timeout on freeze API in order to thaw the filesystem automatically. It can prevent a filesystem from staying frozen forever. (Because a freezer may cause a deadlock by accessing the frozen filesystem.)
Any comments are very welcome.
Cheers, Takashi
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