Since commit 64bc06bb32ee ("gfs2: iomap buffered write support"), gfs2 is doing
buffered writes by starting a transaction in iomap_begin, writing a range of
pages, and ending that transaction in iomap_end. This approach suffers from
two problems:
(1) Any allocations necessary for the write are done in iomap_begin, so when
the data aren't journaled, there is no need for keeping the transaction open
until iomap_end.
(2) Transactions keep the gfs2 log flush lock held. When
iomap_file_buffered_write calls balance_dirty_pages, this can end up calling
gfs2_write_inode, which will try to flush the log. This requires taking the
log flush lock which is already held, resulting in a deadlock.
Fix both of these issues by not keeping transactions open from iomap_begin to
iomap_end. Instead, start a small transaction in page_prepare and end it in
page_done when necessary.
Reported-by: Edwin Török <edvin.torok@xxxxxxxxxx>
Fixes: 64bc06bb32ee ("gfs2: iomap buffered write support")
Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
Signed-off-by: Bob Peterson <rpeterso@xxxxxxxxxx>
---
fs/gfs2/aops.c | 14 ++++++---
fs/gfs2/bmap.c | 83 +++++++++++++++++++++++++-------------------------
2 files changed, 52 insertions(+), 45 deletions(-)
diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index 05dd78f4b2b3..6210d4429d84 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -649,7 +649,7 @@ static int gfs2_readpages(struct file *file, struct address_space *mapping,
*/
void adjust_fs_space(struct inode *inode)
{
- struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
+ struct gfs2_sbd *sdp = GFS2_SB(inode);
struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
@@ -657,10 +657,13 @@ void adjust_fs_space(struct inode *inode)
struct buffer_head *m_bh, *l_bh;
u64 fs_total, new_free;
+ if (gfs2_trans_begin(sdp, 2 * RES_STATFS, 0) != 0)
+ return;
+
/* Total up the file system space, according to the latest rindex. */
fs_total = gfs2_ri_total(sdp);
if (gfs2_meta_inode_buffer(m_ip, &m_bh) != 0)
- return;
+ goto out;
spin_lock(&sdp->sd_statfs_spin);
gfs2_statfs_change_in(m_sc, m_bh->b_data +
@@ -675,11 +678,14 @@ void adjust_fs_space(struct inode *inode)
gfs2_statfs_change(sdp, new_free, new_free, 0);
if (gfs2_meta_inode_buffer(l_ip, &l_bh) != 0)
- goto out;
+ goto out2;
update_statfs(sdp, m_bh, l_bh);
brelse(l_bh);
-out:
+out2:
brelse(m_bh);
+out:
+ sdp->sd_rindex_uptodate = 0;
+ gfs2_trans_end(sdp);
}
/**
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 6b980703bae7..27c82f4aaf32 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -994,7 +994,9 @@ static void gfs2_write_unlock(struct inode *inode)
static int gfs2_iomap_page_prepare(struct inode *inode, loff_t pos,
unsigned len, struct iomap *iomap)
{
- return 0;
+ struct gfs2_sbd *sdp = GFS2_SB(inode);
+
+ return gfs2_trans_begin(sdp, RES_DINODE + (len >> inode->i_blkbits), 0);
}
static void gfs2_iomap_page_done(struct inode *inode, loff_t pos,
@@ -1002,9 +1004,11 @@ static void gfs2_iomap_page_done(struct inode *inode, loff_t pos,
struct iomap *iomap)
{
struct gfs2_inode *ip = GFS2_I(inode);
+ struct gfs2_sbd *sdp = GFS2_SB(inode);
- if (page)
+ if (page && !gfs2_is_stuffed(ip))
gfs2_page_add_databufs(ip, page, offset_in_page(pos), copied);
+ gfs2_trans_end(sdp);
}
static const struct iomap_page_ops gfs2_iomap_page_ops = {
@@ -1064,31 +1068,45 @@ static int gfs2_iomap_begin_write(struct inode *inode, loff_t pos,
if (alloc_required)
rblocks += gfs2_rg_blocks(ip, data_blocks + ind_blocks);
- ret = gfs2_trans_begin(sdp, rblocks, iomap->length >> inode->i_blkbits);
- if (ret)
- goto out_trans_fail;
+ if (unstuff || iomap->type == IOMAP_HOLE) {
+ struct gfs2_trans *tr;
- if (unstuff) {
- ret = gfs2_unstuff_dinode(ip, NULL);
- if (ret)
- goto out_trans_end;
- release_metapath(mp);
- ret = gfs2_iomap_get(inode, iomap->offset, iomap->length,
- flags, iomap, mp);
+ ret = gfs2_trans_begin(sdp, rblocks,
+ iomap->length >> inode->i_blkbits);
if (ret)
- goto out_trans_end;
- }
+ goto out_trans_fail;
- if (iomap->type == IOMAP_HOLE) {
- ret = gfs2_iomap_alloc(inode, iomap, flags, mp);
- if (ret) {
- gfs2_trans_end(sdp);
- gfs2_inplace_release(ip);
- punch_hole(ip, iomap->offset, iomap->length);
- goto out_qunlock;
+ if (unstuff) {
+ ret = gfs2_unstuff_dinode(ip, NULL);
+ if (ret)
+ goto out_trans_end;
+ release_metapath(mp);
+ ret = gfs2_iomap_get(inode, iomap->offset,
+ iomap->length, flags, iomap, mp);
+ if (ret)
+ goto out_trans_end;
}
+
+ if (iomap->type == IOMAP_HOLE) {
+ ret = gfs2_iomap_alloc(inode, iomap, flags, mp);
+ if (ret) {
+ gfs2_trans_end(sdp);
+ gfs2_inplace_release(ip);
+ punch_hole(ip, iomap->offset, iomap->length);
+ goto out_qunlock;
+ }
+ }
+
+ tr = current->journal_info;
+ if (tr->tr_num_buf_new)
+ __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
+ else
+ gfs2_trans_add_meta(ip->i_gl, mp->mp_bh[0]);
+
+ gfs2_trans_end(sdp);
}
- if (!gfs2_is_stuffed(ip) && gfs2_is_jdata(ip))
+
+ if (gfs2_is_stuffed(ip) || gfs2_is_jdata(ip))
iomap->page_ops = &gfs2_iomap_page_ops;
return 0;
@@ -1128,10 +1146,6 @@ static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
iomap->type != IOMAP_MAPPED)
ret = -ENOTBLK;
}
- if (!ret) {
- get_bh(mp.mp_bh[0]);
- iomap->private = mp.mp_bh[0];
- }
release_metapath(&mp);
trace_gfs2_iomap_end(ip, iomap, ret);
return ret;
@@ -1142,27 +1156,16 @@ static int gfs2_iomap_end(struct inode *inode, loff_t pos, loff_t length,
{
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
- struct gfs2_trans *tr = current->journal_info;
- struct buffer_head *dibh = iomap->private;
if ((flags & (IOMAP_WRITE | IOMAP_DIRECT)) != IOMAP_WRITE)
goto out;
- if (iomap->type != IOMAP_INLINE) {
+ if (!gfs2_is_stuffed(ip))
gfs2_ordered_add_inode(ip);
- if (tr->tr_num_buf_new)
- __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
- else
- gfs2_trans_add_meta(ip->i_gl, dibh);
- }
-
- if (inode == sdp->sd_rindex) {
+ if (inode == sdp->sd_rindex)
adjust_fs_space(inode);
- sdp->sd_rindex_uptodate = 0;
- }
- gfs2_trans_end(sdp);
gfs2_inplace_release(ip);
if (length != written && (iomap->flags & IOMAP_F_NEW)) {
@@ -1182,8 +1185,6 @@ static int gfs2_iomap_end(struct inode *inode, loff_t pos, loff_t length,
gfs2_write_unlock(inode);
out:
- if (dibh)
- brelse(dibh);
return 0;
}
--
2.20.1
