Before this patch, gfs2 kept its own address space for rgrps, but this caused a lockdep problem because vfs assumes a 1:1 relationship between address spaces and their inode. One problematic area is this:
gfs2_unpin mark_buffer_dirty(bh); mapping = page_mapping(page); __set_page_dirty(page, mapping, memcg, 0); xa_lock_irqsave(&mapping->i_pages, flags); ^---locks page->mapping->i_pages account_page_dirtied(page, mapping) struct inode *inode = mapping->host; ^---assumes the mapping points to an inode inode_to_wb(inode) WARN_ON_ONCE !lockdep_is_held(&inode->i_mapping-> i_pages.xa_lock) It manifests as a lockdep warning you see in the last line. This patch removes sd_aspace in favor of an entire inode, sd_inode. Functions that need to access the address space may use a new function that follows the inode to its address space. This creates the 1:1 relation between the inode and its address space, so lockdep doesn't complain. This is how some other file systems manage their metadata, such as btrfs. Signed-off-by: Bob Peterson <rpete...@redhat.com> --- fs/gfs2/glops.c | 4 ++-- fs/gfs2/incore.h | 7 ++++++- fs/gfs2/meta_io.c | 2 +- fs/gfs2/meta_io.h | 2 -- fs/gfs2/ops_fstype.c | 27 ++++++++++++++++----------- fs/gfs2/super.c | 2 +- 6 files changed, 26 insertions(+), 18 deletions(-) diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c index 744cacd27213..5d755d30d91c 100644 --- a/fs/gfs2/glops.c +++ b/fs/gfs2/glops.c @@ -162,7 +162,7 @@ void gfs2_ail_flush(struct gfs2_glock *gl, bool fsync) static int gfs2_rgrp_metasync(struct gfs2_glock *gl) { struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; - struct address_space *metamapping = &sdp->sd_aspace; + struct address_space *metamapping = gfs2_aspace(sdp); struct gfs2_rgrpd *rgd = gfs2_glock2rgrp(gl); const unsigned bsize = sdp->sd_sb.sb_bsize; loff_t start = (rgd->rd_addr * bsize) & PAGE_MASK; @@ -219,7 +219,7 @@ static int rgrp_go_sync(struct gfs2_glock *gl) static void rgrp_go_inval(struct gfs2_glock *gl, int flags) { struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; - struct address_space *mapping = &sdp->sd_aspace; + struct address_space *mapping = gfs2_aspace(sdp); struct gfs2_rgrpd *rgd = gfs2_glock2rgrp(gl); const unsigned bsize = sdp->sd_sb.sb_bsize; loff_t start = (rgd->rd_addr * bsize) & PAGE_MASK; diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h index 6f31a067a5f2..4a03c3031347 100644 --- a/fs/gfs2/incore.h +++ b/fs/gfs2/incore.h @@ -795,7 +795,7 @@ struct gfs2_sbd { /* Log stuff */ - struct address_space sd_aspace; + struct inode *sd_inode; spinlock_t sd_log_lock; @@ -851,6 +851,11 @@ struct gfs2_sbd { unsigned long sd_glock_dqs_held; }; +static inline struct address_space *gfs2_aspace(struct gfs2_sbd *sdp) +{ + return sdp->sd_inode->i_mapping; +} + static inline void gfs2_glstats_inc(struct gfs2_glock *gl, int which) { gl->gl_stats.stats[which]++; diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c index 7c9619997355..0123437d9c12 100644 --- a/fs/gfs2/meta_io.c +++ b/fs/gfs2/meta_io.c @@ -120,7 +120,7 @@ struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create) unsigned int bufnum; if (mapping == NULL) - mapping = &sdp->sd_aspace; + mapping = gfs2_aspace(sdp); shift = PAGE_SHIFT - sdp->sd_sb.sb_bsize_shift; index = blkno >> shift; /* convert block to page */ diff --git a/fs/gfs2/meta_io.h b/fs/gfs2/meta_io.h index 21880d72081a..70b9c41ecb46 100644 --- a/fs/gfs2/meta_io.h +++ b/fs/gfs2/meta_io.h @@ -42,8 +42,6 @@ static inline struct gfs2_sbd *gfs2_mapping2sbd(struct address_space *mapping) struct inode *inode = mapping->host; if (mapping->a_ops == &gfs2_meta_aops) return (((struct gfs2_glock *)mapping) - 1)->gl_name.ln_sbd; - else if (mapping->a_ops == &gfs2_rgrp_aops) - return container_of(mapping, struct gfs2_sbd, sd_aspace); else return inode->i_sb->s_fs_info; } diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index 5b90d2b7db47..8051f130cf53 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -72,7 +72,6 @@ void free_sbd(struct gfs2_sbd *sdp) static struct gfs2_sbd *init_sbd(struct super_block *sb) { struct gfs2_sbd *sdp; - struct address_space *mapping; sdp = kzalloc(sizeof(struct gfs2_sbd), GFP_KERNEL); if (!sdp) @@ -112,16 +111,6 @@ static struct gfs2_sbd *init_sbd(struct super_block *sb) INIT_LIST_HEAD(&sdp->sd_sc_inodes_list); - mapping = &sdp->sd_aspace; - - address_space_init_once(mapping); - mapping->a_ops = &gfs2_rgrp_aops; - mapping->host = sb->s_bdev->bd_inode; - mapping->flags = 0; - mapping_set_gfp_mask(mapping, GFP_NOFS); - mapping->private_data = NULL; - mapping->writeback_index = 0; - spin_lock_init(&sdp->sd_log_lock); atomic_set(&sdp->sd_log_pinned, 0); INIT_LIST_HEAD(&sdp->sd_log_revokes); @@ -1140,6 +1129,7 @@ static int gfs2_fill_super(struct super_block *sb, struct fs_context *fc) struct gfs2_sbd *sdp; struct gfs2_holder mount_gh; struct gfs2_holder freeze_gh; + struct address_space *mapping; int error; sdp = init_sbd(sb); @@ -1161,6 +1151,21 @@ static int gfs2_fill_super(struct super_block *sb, struct fs_context *fc) sb->s_flags |= SB_NOSEC; sb->s_magic = GFS2_MAGIC; sb->s_op = &gfs2_super_ops; + + /* Set up an address space for metadata writes */ + sdp->sd_inode = new_inode(sb); + if (!sdp->sd_inode) + goto fail_free; + sdp->sd_inode->i_ino = GFS2_MAGIC; + set_nlink(sdp->sd_inode, 1); + sdp->sd_inode->i_size = i_size_read(sb->s_bdev->bd_inode); + insert_inode_hash(sdp->sd_inode); + + mapping = gfs2_aspace(sdp); + mapping->a_ops = &gfs2_rgrp_aops; + mapping_set_gfp_mask(mapping, GFP_NOFS); + mapping->writeback_index = 0; + sb->s_d_op = &gfs2_dops; sb->s_export_op = &gfs2_export_ops; sb->s_qcop = &gfs2_quotactl_ops; diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index 0a5b7dfa7a45..9857d8725b2d 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -617,13 +617,13 @@ static void gfs2_put_super(struct super_block *sb) gfs2_jindex_free(sdp); /* Take apart glock structures and buffer lists */ gfs2_gl_hash_clear(sdp); - truncate_inode_pages_final(&sdp->sd_aspace); gfs2_delete_debugfs_file(sdp); /* Unmount the locking protocol */ gfs2_lm_unmount(sdp); /* At this point, we're through participating in the lockspace */ gfs2_sys_fs_del(sdp); + iput(sdp->sd_inode); free_sbd(sdp); } -- 2.31.1