From d0a22a4b03b8475b7aa3fa41243c26c291407844 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Mon, 29 Apr 2019 20:50:30 +0100 Subject: gfs2: Fix iomap write page reclaim deadlock 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 Fixes: 64bc06bb32ee ("gfs2: iomap buffered write support") Signed-off-by: Andreas Gruenbacher Signed-off-by: Bob Peterson --- fs/gfs2/aops.c | 14 +++++++--- fs/gfs2/bmap.c | 88 ++++++++++++++++++++++++++++++++-------------------------- 2 files changed, 58 insertions(+), 44 deletions(-) (limited to 'fs/gfs2') 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 @@ out_uninit: */ 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 6f1f0d30fe29..f42718dd292f 100644 --- a/fs/gfs2/bmap.c +++ b/fs/gfs2/bmap.c @@ -991,17 +991,28 @@ static void gfs2_write_unlock(struct inode *inode) gfs2_glock_dq_uninit(&ip->i_gh); } +static int gfs2_iomap_page_prepare(struct inode *inode, loff_t pos, + unsigned len, struct iomap *iomap) +{ + 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, unsigned copied, struct page *page, 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 = { + .page_prepare = gfs2_iomap_page_prepare, .page_done = gfs2_iomap_page_done, }; @@ -1057,31 +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); + ret = gfs2_trans_begin(sdp, rblocks, + iomap->length >> inode->i_blkbits); 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; - } + 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; @@ -1121,10 +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; @@ -1135,27 +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)) { @@ -1175,8 +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; } -- cgit v1.2.3-55-g7522