From 54693e9a448c552906f54a44ac6c5757f03eb242 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Tue, 30 Nov 2021 18:26:15 +0100 Subject: [PATCH] gfs2: gfs2_create_inode rework When gfs2_lookup_by_inum() calls gfs2_inode_lookup() for an uncached inode, gfs2_inode_lookup() will place a new tentative inode into the inode cache before verifying that there is a valid inode at the given address. This can race with gfs2_create_inode() which doesn't check for duplicates inodes. gfs2_create_inode() will try to assign the new inode to the corresponding inode glock, and glock_set_object() will complain that the glock is still in use by gfs2_inode_lookup's tentative inode. We noticed this bug after adding commit 2cb80baed495 ("gfs2: Cancel remote delete work asynchronously") which allowed delete_work_func() to race with gfs2_create_inode(), but the same race exists for open-by-handle. Fix that by switching from insert_inode_hash() to insert_inode_locked4(), which does check for duplicate inodes. We know we've just managed to to allocate the new inode, so an inode tentatively created by gfs2_inode_lookup() will eventually go away and insert_inode_locked4() will always succeed. In addition, don't flush the inode glock work anymore (this can now only make things worse) and clean up glock_{set,clear}_object for the inode glock somewhat. Signed-off-by: Andreas Gruenbacher --- fs/gfs2/inode.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c index d73b2933fdb87..89905f4f29bb6 100644 --- a/fs/gfs2/inode.c +++ b/fs/gfs2/inode.c @@ -707,18 +707,19 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry, error = gfs2_glock_get(sdp, ip->i_no_addr, &gfs2_inode_glops, CREATE, &ip->i_gl); if (error) goto fail_free_inode; - flush_delayed_work(&ip->i_gl->gl_work); error = gfs2_glock_get(sdp, ip->i_no_addr, &gfs2_iopen_glops, CREATE, &io_gl); if (error) goto fail_free_inode; gfs2_cancel_delete_work(io_gl); + error = insert_inode_locked4(inode, ip->i_no_addr, iget_test, &ip->i_no_addr); + BUG_ON(error); + error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_SKIP, ghs + 1); if (error) goto fail_gunlock2; - glock_set_object(ip->i_gl, ip); error = gfs2_trans_begin(sdp, blocks, 0); if (error) goto fail_gunlock2; @@ -734,9 +735,9 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry, if (error) goto fail_gunlock2; + glock_set_object(ip->i_gl, ip); glock_set_object(io_gl, ip); gfs2_set_iop(inode); - insert_inode_hash(inode); free_vfs_inode = 0; /* After this point, the inode is no longer considered free. Any failures need to undo @@ -778,17 +779,17 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry, gfs2_glock_dq_uninit(ghs + 1); gfs2_glock_put(io_gl); gfs2_qa_put(dip); + unlock_new_inode(inode); return error; fail_gunlock3: + glock_clear_object(ip->i_gl, ip); glock_clear_object(io_gl, ip); gfs2_glock_dq_uninit(&ip->i_iopen_gh); fail_gunlock2: - glock_clear_object(io_gl, ip); gfs2_glock_put(io_gl); fail_free_inode: if (ip->i_gl) { - glock_clear_object(ip->i_gl, ip); if (free_vfs_inode) /* else evict will do the put for us */ gfs2_glock_put(ip->i_gl); } @@ -806,7 +807,10 @@ fail_gunlock: mark_inode_dirty(inode); set_bit(free_vfs_inode ? GIF_FREE_VFS_INODE : GIF_ALLOC_FAILED, &GFS2_I(inode)->i_flags); - iput(inode); + if (inode->i_state & I_NEW) + iget_failed(inode); + else + iput(inode); } if (gfs2_holder_initialized(ghs + 1)) gfs2_glock_dq_uninit(ghs + 1); -- 2.39.5