From 7700e4c2b000475ba6a867a9c546a52c9ea4be52 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Thu, 19 Oct 2017 11:08:52 -0700
Subject: [PATCH 42/77] xfs: don't rely on extent indices in
xfs_bmap_insert_extents
Git-commit: 5936dc543cfd27de74cd34fdc928b5115cec53d1
Patch-mainline: v4.15-rc1
References: bsc#1095344
Rewrite xfs_bmap_insert_extents so that we don't rely on extent indices
except for iterating over them. Not being able to iterate to the previous
extent or finding the extent that stop_fsb is in are sufficient exit
conditions, and we don't need to do any extent count games given that:
a) we already flushed all delalloc extents past our start offset
before doing the operation
b) xfs_iext_count() includes delalloc extents anyway
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
fs/xfs/libxfs/xfs_bmap.c | 47 +++++++++--------------------------------------
1 file changed, 9 insertions(+), 38 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 7787ac16c752..4478bc084528 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -5724,10 +5724,8 @@ xfs_bmap_insert_extents(
struct xfs_mount *mp = ip->i_mount;
struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, whichfork);
struct xfs_btree_cur *cur = NULL;
- struct xfs_bmbt_irec got, next, s;
+ struct xfs_bmbt_irec got, next;
xfs_extnum_t current_ext;
- xfs_extnum_t total_extents;
- xfs_extnum_t stop_extent;
xfs_fileoff_t new_startoff;
int error = 0;
int logflags = 0;
@@ -5758,37 +5756,14 @@ xfs_bmap_insert_extents(
cur->bc_private.b.flags = 0;
}
- /*
- * There may be delalloc extents in the data fork before the range we
- * are collapsing out, so we cannot use the count of real extents here.
- * Instead we have to calculate it from the incore fork.
- */
- total_extents = xfs_iext_count(ifp);
- if (total_extents == 0) {
- *done = true;
- goto del_cursor;
- }
-
- /*
- * In case of first right shift, we need to initialize next_fsb
- */
if (*next_fsb == NULLFSBLOCK) {
- current_ext = total_extents - 1;
- xfs_iext_get_extent(ifp, current_ext, &got);
- if (stop_fsb > got.br_startoff) {
+ current_ext = xfs_iext_count(ifp) - 1;
+ if (!xfs_iext_get_extent(ifp, current_ext, &got) ||
+ stop_fsb > got.br_startoff) {
*done = true;
goto del_cursor;
}
- *next_fsb = got.br_startoff;
} else {
- /*
- * Look up the extent index for the fsb where we start shifting. We can
- * henceforth iterate with current_ext as extent list changes are locked
- * out via ilock.
- *
- * If next_fsb lies in a hole beyond which there are no extents we are
- * done.
- */
if (!xfs_iext_lookup_extent(ip, ifp, *next_fsb, ¤t_ext,
&got)) {
*done = true;
@@ -5797,18 +5772,13 @@ xfs_bmap_insert_extents(
}
XFS_WANT_CORRUPTED_RETURN(mp, !isnullstartblock(got.br_startblock));
- /* Lookup the extent index at which we have to stop */
- xfs_iext_lookup_extent(ip, ifp, stop_fsb, &stop_extent, &s);
- /* Make stop_extent exclusive of shift range */
- stop_extent--;
- if (current_ext <= stop_extent) {
+ if (stop_fsb >= got.br_startoff + got.br_blockcount) {
error = -EIO;
goto del_cursor;
}
new_startoff = got.br_startoff + offset_shift_fsb;
- if (current_ext < total_extents - 1) {
- xfs_iext_get_extent(ifp, current_ext + 1, &next);
+ if (xfs_iext_get_extent(ifp, current_ext + 1, &next)) {
if (new_startoff + got.br_blockcount > next.br_startoff) {
error = -EINVAL;
goto del_cursor;
@@ -5828,11 +5798,12 @@ xfs_bmap_insert_extents(
cur, &logflags, dfops, new_startoff);
if (error)
goto del_cursor;
- if (--current_ext == stop_extent) {
+
+ if (!xfs_iext_get_extent(ifp, --current_ext, &got) ||
+ stop_fsb >= got.br_startoff + got.br_blockcount) {
*done = true;
goto del_cursor;
}
- xfs_iext_get_extent(ifp, current_ext, &got);
*next_fsb = got.br_startoff;
del_cursor:
--
2.7.4