Commit 4e79e3f0 authored Nov 12, 2020 by Bob Peterson Committed by Andreas Gruenbacher Nov 12, 2020

gfs2: Fix case in which ail writes are done to jdata holes



Patch b2a846db ("gfs2: Ignore journal log writes for jdata holes")
tried (unsuccessfully) to fix a case in which writes were done to jdata
blocks, the blocks are sent to the ail list, then a punch_hole or truncate
operation caused the blocks to be freed. In other words, the ail items
are for jdata holes. Before b2a846db, the jdata hole caused function
gfs2_block_map to return -EIO, which was eventually interpreted as an
IO error to the journal, and then withdraw.

This patch changes function gfs2_get_block_noalloc, which is only used
for jdata writes, so it returns -ENODATA rather than -EIO, and when
-ENODATA is returned to gfs2_ail1_start_one, the error is ignored.
We can safely ignore it because gfs2_ail1_start_one is only called
when the jdata pages have already been written and truncated, so the
ail1 content no longer applies.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

parent d3039c06

fs/gfs2/aops.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -77,7 +77,7 @@ static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
		if (error)
		return error;
		if (!buffer_mapped(bh_result))
		return -EIO;
		return -ENODATA;
		return 0;
		}

fs/gfs2/log.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -132,6 +132,8 @@ __acquires(&sdp->sd_ail_lock)
		spin_unlock(&sdp->sd_ail_lock);
		ret = generic_writepages(mapping, wbc);
		spin_lock(&sdp->sd_ail_lock);
		if (ret == -ENODATA) /* if a jdata write into a new hole */
		ret = 0; /* ignore it */
		if (ret \|\| wbc->nr_to_write <= 0)
		break;
		return -EBUSY;

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