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gfs2: clean up iopen glock mess in gfs2_create_inode 

Before this patch, gfs2_create_inode had a use-after-free for the
iopen glock in some error paths because it did this:

	gfs2_glock_put(io_gl);
fail_gunlock2:
	if (io_gl)
		clear_bit(GLF_INODE_CREATING, &io_gl->gl_flags);

In some cases, the io_gl was used for create and only had one
reference, so the glock might be freed before the clear_bit().
This patch tries to straighten it out by only jumping to the
error paths where iopen is properly set, and moving the
gfs2_glock_put after the clear_bit.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
This commit is contained in:
Bob Peterson 2019-11-19 11:40:46 -05:00 committed by Andreas Gruenbacher
parent d99724c3c3
commit 2c47c1be51
1 changed files with 7 additions and 6 deletions
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13
fs/gfs2/inode.c
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@ -712,7 +712,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
error = gfs2_trans_begin(sdp, blocks, 0);
if (error)
goto fail_gunlock2;
goto fail_free_inode;
if (blocks > 1) {
ip->i_eattr = ip->i_no_addr + 1;
@ -723,7 +723,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
error = gfs2_glock_get(sdp, ip->i_no_addr, &gfs2_iopen_glops, CREATE, &io_gl);
if (error)
goto fail_gunlock2;
goto fail_free_inode;
BUG_ON(test_and_set_bit(GLF_INODE_CREATING, &io_gl->gl_flags));
@ -732,7 +732,6 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
goto fail_gunlock2;
glock_set_object(ip->i_iopen_gh.gh_gl, ip);
gfs2_glock_put(io_gl);
gfs2_set_iop(inode);
insert_inode_hash(inode);
@ -765,6 +764,8 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
mark_inode_dirty(inode);
d_instantiate(dentry, inode);
/* After instantiate, errors should result in evict which will destroy
* both inode and iopen glocks properly. */
if (file) {
file->f_mode |= FMODE_CREATED;
error = finish_open(file, dentry, gfs2_open_common);
@ -772,15 +773,15 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
gfs2_glock_dq_uninit(ghs);
gfs2_glock_dq_uninit(ghs + 1);
clear_bit(GLF_INODE_CREATING, &io_gl->gl_flags);
gfs2_glock_put(io_gl);
return error;
fail_gunlock3:
glock_clear_object(io_gl, ip);
gfs2_glock_dq_uninit(&ip->i_iopen_gh);
gfs2_glock_put(io_gl);
fail_gunlock2:
if (io_gl)
clear_bit(GLF_INODE_CREATING, &io_gl->gl_flags);
clear_bit(GLF_INODE_CREATING, &io_gl->gl_flags);
gfs2_glock_put(io_gl);
fail_free_inode:
if (ip->i_gl) {
glock_clear_object(ip->i_gl, ip);