On Monday 20 October 2014 at 12:54:13, Edward Shishkin wrote: > On 08/17/2014 11:52 PM, Ivan Shapovalov wrote: > > [...] > > + /* > > + * Grab some sane amount of space. > > + * We will allocate blocks until end of the partition or until > > + * the grabbed space is exhausted. > > + */ > > + ret = reiser4_grab_reserved(super, 0, BA_CAN_COMMIT | BA_SOME_SPACE); > > > reiser4_grab_reserved() grabs space from the reserved area (5%). > This is needed to make sure that unlink(), truncate(), etc. won't > fail, if there is no free space on disk. I don't think that FITRIM > ioctl needs this reserved area. Well, IIUC, it doesn't hurt: any "legitimate" user of the reserved space will block on the mutex and eventually proceed. At the same time, given a filesystem with (5% + eps) free space left, not using the reserved space will result in trimming of (eps) blocks at a time. Anyway, I should also fix calculation of space to grab in 1/9: if BA_RESERVED is not set, then the amount to grab should be calculated as 25% of non-reserved free space, not as 25% of all free space... > If BA_SOME_SPACE is set, then you lock a superblock, and grab 25% of > the current free space. It means that your grab will always succeed, > so that BA_CAN_COMMIT flag is also not needed. If we decide on dropping BA_RESERVED, then you're right here; reiser4_grab(...BA_SOME_SPACE...) won't return ENOSPC and so this is pointless. If we decide on keeping BA_RESERVED, then this should also stay in order not to trigger the assertion. Thanks, -- Ivan Shapovalov / intelfx /
Attachment:
signature.asc
Description: This is a digitally signed message part.
