xfs: rewrite xfs_dq_get_next_id using xfs_iext_lookup_extent

This goes straight to a single lookup in the extent list and avoids a
roundtrip through two layers that don't add any value for the simple
quoata file that just has data or holes and no page cache, delayed
allocation, unwritten extent or COW fork (which btw, doesn't seem to
be handled by the existing SEEK HOLE/DATA code).

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

1 files changed, 22 insertions, 44 deletions

diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
index 79668142afc1..8848b397e7a8 100644
--- a/fs/xfs/xfs_dquot.c
+++ b/fs/xfs/xfs_dquot.c
@@ -701,21 +701,18 @@ error0:
  */
 static int
 xfs_dq_get_next_id(
-        xfs_mount_t             *mp,
+        struct xfs_mount        *mp,
         uint                    type,
-        xfs_dqid_t              *id,
-        loff_t                  eof)
+        xfs_dqid_t              *id)
 {
-        struct xfs_inode        *quotip;
+        struct xfs_inode        *quotip = xfs_quota_inode(mp, type);
+        xfs_dqid_t              next_id = *id + 1; /* simple advance */
+        uint                    lock_flags;
+        struct xfs_bmbt_irec    got;
+        xfs_extnum_t            idx;
         xfs_fsblock_t           start;
-        loff_t                  offset;
-        uint                    lock;
-        xfs_dqid_t              next_id;
         int                     error = 0;
 
-        /* Simple advance */
-        next_id = *id + 1;
-
         /* If we'd wrap past the max ID, stop */
         if (next_id < *id)
                 return -ENOENT;
@@ -729,23 +726,20 @@ xfs_dq_get_next_id(
         /* Nope, next_id is now past the current chunk, so find the next one */
         start = (xfs_fsblock_t)next_id / mp->m_quotainfo->qi_dqperchunk;
 
-        quotip = xfs_quota_inode(mp, type);
-        lock = xfs_ilock_data_map_shared(quotip);
-
-        offset = __xfs_seek_hole_data(VFS_I(quotip), XFS_FSB_TO_B(mp, start),
-                                      eof, SEEK_DATA);
-        if (offset < 0)
-                error = offset;
-
-        xfs_iunlock(quotip, lock);
+        lock_flags = xfs_ilock_data_map_shared(quotip);
+        if (!(quotip->i_df.if_flags & XFS_IFEXTENTS)) {
+                error = xfs_iread_extents(NULL, quotip, XFS_DATA_FORK);
+                if (error)
+                        return error;
+        }
 
-        /* -ENXIO is essentially "no more data" */
-        if (error)
-                return (error == -ENXIO ? -ENOENT: error);
+        if (xfs_iext_lookup_extent(quotip, &quotip->i_df, start, &idx, &got))
+                *id = got.br_startoff * mp->m_quotainfo->qi_dqperchunk;
+        else
+                error = -ENOENT;
+        xfs_iunlock(quotip, lock_flags);
 
-        /* Convert next data offset back to a quota id */
-        *id = XFS_B_TO_FSB(mp, offset) * mp->m_quotainfo->qi_dqperchunk;
-        return 0;
+        return error;
 }
 
 /*
@@ -768,7 +762,6 @@ xfs_qm_dqget(
         struct xfs_quotainfo    *qi = mp->m_quotainfo;
         struct radix_tree_root *tree = xfs_dquot_tree(qi, type);
         struct xfs_dquot        *dqp;
-        loff_t                  eof = 0;
         int                     error;
 
         ASSERT(XFS_IS_QUOTA_RUNNING(mp));
@@ -796,21 +789,6 @@ xfs_qm_dqget(
         }
 #endif
 
-        /* Get the end of the quota file if we need it */
-        if (flags & XFS_QMOPT_DQNEXT) {
-                struct xfs_inode        *quotip;
-                xfs_fileoff_t           last;
-                uint                    lock_mode;
-
-                quotip = xfs_quota_inode(mp, type);
-                lock_mode = xfs_ilock_data_map_shared(quotip);
-                error = xfs_bmap_last_offset(quotip, &last, XFS_DATA_FORK);
-                xfs_iunlock(quotip, lock_mode);
-                if (error)
-                        return error;
-                eof = XFS_FSB_TO_B(mp, last);
-        }
-
 restart:
         mutex_lock(&qi->qi_tree_lock);
         dqp = radix_tree_lookup(tree, id);
@@ -829,7 +807,7 @@ restart:
                         if (XFS_IS_DQUOT_UNINITIALIZED(dqp)) {
                                 xfs_dqunlock(dqp);
                                 mutex_unlock(&qi->qi_tree_lock);
-                                error = xfs_dq_get_next_id(mp, type, &id, eof);
+                                error = xfs_dq_get_next_id(mp, type, &id);
                                 if (error)
                                         return error;
                                 goto restart;
@@ -864,7 +842,7 @@ restart:
 
         /* If we are asked to find next active id, keep looking */
         if (error == -ENOENT && (flags & XFS_QMOPT_DQNEXT)) {
-                error = xfs_dq_get_next_id(mp, type, &id, eof);
+                error = xfs_dq_get_next_id(mp, type, &id);
                 if (!error)
                         goto restart;
         }
@@ -923,7 +901,7 @@ restart:
         if (flags & XFS_QMOPT_DQNEXT) {
                 if (XFS_IS_DQUOT_UNINITIALIZED(dqp)) {
                         xfs_qm_dqput(dqp);
-                        error = xfs_dq_get_next_id(mp, type, &id, eof);
+                        error = xfs_dq_get_next_id(mp, type, &id);
                         if (error)
                                 return error;
                         goto restart;