Re: [PATCH v2 1/5] fs, xfs: introduce S_IOMAP_IMMUTABLE

2017-08-11 Thread Christoph Hellwig
On Mon, Aug 07, 2017 at 10:25:02AM +1000, Dave Chinner wrote: > We've always told people not to do those "horrible abuses" because > of the TOCTOU race conditions inherent in getting accurate > BMAP/FIEMAP information to userspace. However, immutable extent maps > solve the TOCTOU problem and so

Re: [PATCH v2 1/5] fs, xfs: introduce S_IOMAP_IMMUTABLE

2017-08-06 Thread Dave Chinner
On Sat, Aug 05, 2017 at 11:47:08AM +0200, Christoph Hellwig wrote: > NAK^4. > > We should not allow users to create immutable files. We have > proper ways to synchronize I/O, and this is just an invitation > for horrible abuses that should not be allowed, and which we've > always people told not

Re: [PATCH v2 1/5] fs, xfs: introduce S_IOMAP_IMMUTABLE

2017-08-05 Thread Christoph Hellwig
NAK^4. We should not allow users to create immutable files. We have proper ways to synchronize I/O, and this is just an invitation for horrible abuses that should not be allowed, and which we've always people told not to do. ___ Linux-nvdimm mailing

Re: [PATCH v2 1/5] fs, xfs: introduce S_IOMAP_IMMUTABLE

2017-08-04 Thread Dan Williams
On Fri, Aug 4, 2017 at 1:00 PM, Darrick J. Wong wrote: > On Thu, Aug 03, 2017 at 07:28:10PM -0700, Dan Williams wrote: >> An inode with this flag set indicates that the file's block map cannot >> be changed from the currently allocated set. >> >> The implementation of

Re: [PATCH v2 1/5] fs, xfs: introduce S_IOMAP_IMMUTABLE

2017-08-04 Thread Darrick J. Wong
On Thu, Aug 03, 2017 at 07:28:10PM -0700, Dan Williams wrote: > An inode with this flag set indicates that the file's block map cannot > be changed from the currently allocated set. > > The implementation of toggling the flag and sealing the state of the > extent map is saved for a later patch.