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-rw-r--r--fs/xfs/xfs_trans.c77
1 files changed, 40 insertions, 37 deletions
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 2caa078..356d662 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -638,11 +638,23 @@ xfs_trans_apply_sb_deltas(
}
/*
- * xfs_trans_unreserve_and_mod_sb() is called to release unused
- * reservations and apply superblock counter changes to the in-core
- * superblock.
+ * xfs_trans_unreserve_and_mod_sb() is called to release unused reservations
+ * and apply superblock counter changes to the in-core superblock. The
+ * t_res_fdblocks_delta and t_res_frextents_delta fields are explicitly NOT
+ * applied to the in-core superblock. The idea is that that has already been
+ * done.
*
* This is done efficiently with a single call to xfs_mod_incore_sb_batch().
+ * However, we have to ensure that we only modify each superblock field only
+ * once because the application of the delta values may not be atomic. That can
+ * lead to ENOSPC races occurring if we have two separate modifcations of the
+ * free space counter to put back the entire reservation and then take away
+ * what we used.
+ *
+ * If we are not logging superblock counters, then the inode allocated/free and
+ * used block counts are not updated in the on disk superblock. In this case,
+ * XFS_TRANS_SB_DIRTY will not be set when the transaction is updated but we
+ * still need to update the incore superblock with the changes.
*/
STATIC void
xfs_trans_unreserve_and_mod_sb(
@@ -654,42 +666,43 @@ xfs_trans_unreserve_and_mod_sb(
/* REFERENCED */
int error;
int rsvd;
+ int64_t blkdelta = 0;
+ int64_t rtxdelta = 0;
msbp = msb;
rsvd = (tp->t_flags & XFS_TRANS_RESERVE) != 0;
- /*
- * Release any reserved blocks. Any that were allocated
- * will be taken back again by fdblocks_delta below.
- */
- if (tp->t_blk_res > 0) {
+ /* calculate free blocks delta */
+ if (tp->t_blk_res > 0)
+ blkdelta = tp->t_blk_res;
+
+ if ((tp->t_fdblocks_delta != 0) &&
+ (xfs_sb_version_haslazysbcount(&mp->m_sb) ||
+ (tp->t_flags & XFS_TRANS_SB_DIRTY)))
+ blkdelta += tp->t_fdblocks_delta;
+
+ if (blkdelta != 0) {
msbp->msb_field = XFS_SBS_FDBLOCKS;
- msbp->msb_delta = tp->t_blk_res;
+ msbp->msb_delta = blkdelta;
msbp++;
}
- /*
- * Release any reserved real time extents . Any that were
- * allocated will be taken back again by frextents_delta below.
- */
- if (tp->t_rtx_res > 0) {
+ /* calculate free realtime extents delta */
+ if (tp->t_rtx_res > 0)
+ rtxdelta = tp->t_rtx_res;
+
+ if ((tp->t_frextents_delta != 0) &&
+ (tp->t_flags & XFS_TRANS_SB_DIRTY))
+ rtxdelta += tp->t_frextents_delta;
+
+ if (rtxdelta != 0) {
msbp->msb_field = XFS_SBS_FREXTENTS;
- msbp->msb_delta = tp->t_rtx_res;
+ msbp->msb_delta = rtxdelta;
msbp++;
}
- /*
- * Apply any superblock modifications to the in-core version.
- * The t_res_fdblocks_delta and t_res_frextents_delta fields are
- * explicitly NOT applied to the in-core superblock.
- * The idea is that that has already been done.
- *
- * If we are not logging superblock counters, then the inode
- * allocated/free and used block counts are not updated in the
- * on disk superblock. In this case, XFS_TRANS_SB_DIRTY will
- * not be set when the transaction is updated but we still need
- * to update the incore superblock with the changes.
- */
+ /* apply remaining deltas */
+
if (xfs_sb_version_haslazysbcount(&mp->m_sb) ||
(tp->t_flags & XFS_TRANS_SB_DIRTY)) {
if (tp->t_icount_delta != 0) {
@@ -702,19 +715,9 @@ xfs_trans_unreserve_and_mod_sb(
msbp->msb_delta = tp->t_ifree_delta;
msbp++;
}
- if (tp->t_fdblocks_delta != 0) {
- msbp->msb_field = XFS_SBS_FDBLOCKS;
- msbp->msb_delta = tp->t_fdblocks_delta;
- msbp++;
- }
}
if (tp->t_flags & XFS_TRANS_SB_DIRTY) {
- if (tp->t_frextents_delta != 0) {
- msbp->msb_field = XFS_SBS_FREXTENTS;
- msbp->msb_delta = tp->t_frextents_delta;
- msbp++;
- }
if (tp->t_dblocks_delta != 0) {
msbp->msb_field = XFS_SBS_DBLOCKS;
msbp->msb_delta = tp->t_dblocks_delta;
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