From: Andreas Gruenbacher agruenba@redhat.com
[ Upstream commit 554c577cee95bdc1d03d9f457e57dc96eb791845 ]
Currently, instead of performing a short write, iomap_file_buffered_write will fail when part of its iov iterator cannot be read. In contrast, gfs2_file_buffered_write will loop around if it can read part of the iov iterator, so we can end up in an endless loop.
This should be fixed in iomap_file_buffered_write (and also generic_perform_write), but this comes a bit late in the 5.16 development cycle, so work around it in the filesystem by trimming the iov iterator to the known-good size for now.
Signed-off-by: Andreas Gruenbacher agruenba@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/gfs2/file.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index 247b8d95b5ef..97e2793e22d7 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -1021,6 +1021,7 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb, struct gfs2_sbd *sdp = GFS2_SB(inode); struct gfs2_holder *statfs_gh = NULL; size_t prev_count = 0, window_size = 0; + size_t orig_count = iov_iter_count(from); size_t read = 0; ssize_t ret;
@@ -1065,6 +1066,7 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb, if (inode == sdp->sd_rindex) gfs2_glock_dq_uninit(statfs_gh);
+ from->count = orig_count - read; if (should_fault_in_pages(ret, from, &prev_count, &window_size)) { size_t leftover;
@@ -1072,6 +1074,7 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb, leftover = fault_in_iov_iter_readable(from, window_size); gfs2_holder_disallow_demote(gh); if (leftover != window_size) { + from->count = min(from->count, window_size - leftover); if (!gfs2_holder_queued(gh)) { if (read) goto out_uninit;