diff options
Diffstat (limited to 'fs/xfs/xfs_quota.h')
| -rw-r--r-- | fs/xfs/xfs_quota.h | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/fs/xfs/xfs_quota.h b/fs/xfs/xfs_quota.h index c3483bab9cd..40d508be9a0 100644 --- a/fs/xfs/xfs_quota.h +++ b/fs/xfs/xfs_quota.h @@ -108,11 +108,28 @@ typedef struct xfs_dqblk { { XFS_DQ_FREEING, "FREEING" } /* - * In the worst case, when both user and group quotas are on, - * we can have a max of three dquots changing in a single transaction. + * We have the possibility of all three quota types being active at once, and + * hence free space modification requires modification of all three current + * dquots in a single transaction. For this case we need to have a reservation + * of at least 3 dquots. + * + * However, a chmod operation can change both UID and GID in a single + * transaction, resulting in requiring {old, new} x {uid, gid} dquots to be + * modified. Hence for this case we need to reserve space for at least 4 dquots. + * + * And in the worst case, there's a rename operation that can be modifying up to + * 4 inodes with dquots attached to them. In reality, the only inodes that can + * have their dquots modified are the source and destination directory inodes + * due to directory name creation and removal. That can require space allocation + * and/or freeing on both directory inodes, and hence all three dquots on each + * inode can be modified. And if the directories are world writeable, all the + * dquots can be unique and so 6 dquots can be modified.... + * + * And, of course, we also need to take into account the dquot log format item + * used to describe each dquot. */ -#define XFS_DQUOT_LOGRES(mp) (sizeof(xfs_disk_dquot_t) * 3) - +#define XFS_DQUOT_LOGRES(mp) \ + ((sizeof(struct xfs_dq_logformat) + sizeof(struct xfs_disk_dquot)) * 6) /* * These are the structures used to lay out dquots and quotaoff |