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Groups > linux.kernel > #1544187 > unrolled thread
| Started by | Sami Kerola <kerolasa@iki.fi> |
|---|---|
| First post | 2016-12-18 20:00 +0100 |
| Last post | 2016-12-19 23:40 +0100 |
| Articles | 3 — 2 participants |
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[PATCH] vfs: return EOPNOTSUPP when ioctl_fsthaw() is not supported Sami Kerola <kerolasa@iki.fi> - 2016-12-18 20:00 +0100
Re: [PATCH] vfs: return EOPNOTSUPP when ioctl_fsthaw() is not supported Christoph Hellwig <hch@infradead.org> - 2016-12-19 11:30 +0100
Re: [PATCH] vfs: return EOPNOTSUPP when ioctl_fsthaw() is not supported Sami Kerola <kerolasa@iki.fi> - 2016-12-19 23:40 +0100
| From | Sami Kerola <kerolasa@iki.fi> |
|---|---|
| Date | 2016-12-18 20:00 +0100 |
| Subject | [PATCH] vfs: return EOPNOTSUPP when ioctl_fsthaw() is not supported |
| Message-ID | <sPOQF-593-1@gated-at.bofh.it> |
An attempt to freeze a filesystem that does not support such operation is reported as EOPNOTSUPP to user. Running unfreeze to the same filesystem returns EINVAL. Later is a little misleading, users can mix that message with return value from unfreezing when filesystem is not frozen. Signed-off-by: Sami Kerola <kerolasa@iki.fi> --- fs/ioctl.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/ioctl.c b/fs/ioctl.c index cb9b02940805..1d6372ef4008 100644 --- a/fs/ioctl.c +++ b/fs/ioctl.c @@ -566,6 +566,10 @@ static int ioctl_fsthaw(struct file *filp) if (!capable(CAP_SYS_ADMIN)) return -EPERM; + /* If filesystem doesn't support thaw feature, return. */ + if (!sb->s_op->unfreeze_fs) + return -EOPNOTSUPP; + /* Thaw */ if (sb->s_op->thaw_super) return sb->s_op->thaw_super(sb); -- 2.11.0
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| From | Christoph Hellwig <hch@infradead.org> |
|---|---|
| Date | 2016-12-19 11:30 +0100 |
| Subject | Re: [PATCH] vfs: return EOPNOTSUPP when ioctl_fsthaw() is not supported |
| Message-ID | <sQ3mG-6t5-53@gated-at.bofh.it> |
| In reply to | #1544187 |
On Sun, Dec 18, 2016 at 06:57:27PM +0000, Sami Kerola wrote: > An attempt to freeze a filesystem that does not support such operation is > reported as EOPNOTSUPP to user. Running unfreeze to the same filesystem > returns EINVAL. Later is a little misleading, users can mix that message > with return value from unfreezing when filesystem is not frozen. This is going to break gfs2 with it's odd ->that_super method.
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| From | Sami Kerola <kerolasa@iki.fi> |
|---|---|
| Date | 2016-12-19 23:40 +0100 |
| Message-ID | <sQeL8-5pk-21@gated-at.bofh.it> |
| In reply to | #1544437 |
On 19 December 2016 at 10:24, Christoph Hellwig <hch@infradead.org> wrote: > On Sun, Dec 18, 2016 at 06:57:27PM +0000, Sami Kerola wrote: >> An attempt to freeze a filesystem that does not support such operation is >> reported as EOPNOTSUPP to user. Running unfreeze to the same filesystem >> returns EINVAL. Later is a little misleading, users can mix that message >> with return value from unfreezing when filesystem is not frozen. > > This is going to break gfs2 with it's odd ->that_super method. Thank you for feedback, there's just one small problem with it. I don't quite understand the breakage. Proposed change uses similar logic as ioctl_fsfreeze()[1] and it works fine. If I am not entirely mistaking freeze and thaw hooks where added[2] to avoid issues with gfs2. And looking gfs2 super_operations init[3] does not make me any wiser what might be wrong. Maybe feedback had typo s/that_super/thaw_super/[4]. But even then it is unclear to me how a null could cause breakage. [1] https://github.com/torvalds/linux/blob/master/fs/ioctl.c#L553 [2] https://github.com/torvalds/linux/commit/48b6bca6b7b8309697fc8a101793befe92d249d9 [3] https://github.com/torvalds/linux/blob/master/fs/gfs2/super.c#L1683 [4] https://github.com/torvalds/linux/blob/master/fs/super.c#L1446 -- Sami Kerola http://www.iki.fi/kerolasa/
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