Here is a set of small fixes for GFS2. There is a fix to drop

s_umount which is copied in from the core vfs, two patches
 relate to a hard to hit "use after free" and memory leak.
 Two patches related to using DIO and buffered I/O on the same
 file to ensure correct operation in relation to glock state
 changes. The final patch adds an RCU read lock to ensure
 correct locking on an error path.
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Merge tag 'gfs2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-fixes

Pull GFS2 fixes from Steven Whitehouse:
 "Here is a set of small fixes for GFS2.  There is a fix to drop
  s_umount which is copied in from the core vfs, two patches relate to a
  hard to hit "use after free" and memory leak.  Two patches related to
  using DIO and buffered I/O on the same file to ensure correct
  operation in relation to glock state changes.  The final patch adds an
  RCU read lock to ensure correct locking on an error path"

* tag 'gfs2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-fixes:
  GFS2: Fix unsafe dereference in dump_holder()
  GFS2: Wait for async DIO in glock state changes
  GFS2: Fix incorrect invalidation for DIO/buffered I/O
  GFS2: Fix slab memory leak in gfs2_bufdata
  GFS2: Fix use-after-free race when calling gfs2_remove_from_ail
  GFS2: don't hold s_umount over blkdev_put
This commit is contained in:
Linus Torvalds 2014-01-02 12:45:47 -08:00
commit 152b734a9e
6 changed files with 58 additions and 5 deletions

View File

@ -986,6 +986,7 @@ static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
struct address_space *mapping = inode->i_mapping;
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_holder gh;
int rv;
@ -1006,6 +1007,35 @@ static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
if (rv != 1)
goto out; /* dio not valid, fall back to buffered i/o */
/*
* Now since we are holding a deferred (CW) lock at this point, you
* might be wondering why this is ever needed. There is a case however
* where we've granted a deferred local lock against a cached exclusive
* glock. That is ok provided all granted local locks are deferred, but
* it also means that it is possible to encounter pages which are
* cached and possibly also mapped. So here we check for that and sort
* them out ahead of the dio. The glock state machine will take care of
* everything else.
*
* If in fact the cached glock state (gl->gl_state) is deferred (CW) in
* the first place, mapping->nr_pages will always be zero.
*/
if (mapping->nrpages) {
loff_t lstart = offset & (PAGE_CACHE_SIZE - 1);
loff_t len = iov_length(iov, nr_segs);
loff_t end = PAGE_ALIGN(offset + len) - 1;
rv = 0;
if (len == 0)
goto out;
if (test_and_clear_bit(GIF_SW_PAGED, &ip->i_flags))
unmap_shared_mapping_range(ip->i_inode.i_mapping, offset, len);
rv = filemap_write_and_wait_range(mapping, lstart, end);
if (rv)
return rv;
truncate_inode_pages_range(mapping, lstart, end);
}
rv = __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
offset, nr_segs, gfs2_get_block_direct,
NULL, NULL, 0);

View File

@ -1655,6 +1655,7 @@ static int dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
struct task_struct *gh_owner = NULL;
char flags_buf[32];
rcu_read_lock();
if (gh->gh_owner_pid)
gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
@ -1664,6 +1665,7 @@ static int dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
gh_owner ? gh_owner->comm : "(ended)",
(void *)gh->gh_ip);
rcu_read_unlock();
return 0;
}

View File

@ -192,8 +192,11 @@ static void inode_go_sync(struct gfs2_glock *gl)
if (ip && !S_ISREG(ip->i_inode.i_mode))
ip = NULL;
if (ip && test_and_clear_bit(GIF_SW_PAGED, &ip->i_flags))
unmap_shared_mapping_range(ip->i_inode.i_mapping, 0, 0);
if (ip) {
if (test_and_clear_bit(GIF_SW_PAGED, &ip->i_flags))
unmap_shared_mapping_range(ip->i_inode.i_mapping, 0, 0);
inode_dio_wait(&ip->i_inode);
}
if (!test_and_clear_bit(GLF_DIRTY, &gl->gl_flags))
return;
@ -410,6 +413,9 @@ static int inode_go_lock(struct gfs2_holder *gh)
return error;
}
if (gh->gh_state != LM_ST_DEFERRED)
inode_dio_wait(&ip->i_inode);
if ((ip->i_diskflags & GFS2_DIF_TRUNC_IN_PROG) &&
(gl->gl_state == LM_ST_EXCLUSIVE) &&
(gh->gh_state == LM_ST_EXCLUSIVE)) {

View File

@ -551,10 +551,10 @@ void gfs2_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
struct buffer_head *bh = bd->bd_bh;
struct gfs2_glock *gl = bd->bd_gl;
gfs2_remove_from_ail(bd);
bd->bd_bh = NULL;
bh->b_private = NULL;
bd->bd_blkno = bh->b_blocknr;
gfs2_remove_from_ail(bd); /* drops ref on bh */
bd->bd_bh = NULL;
bd->bd_ops = &gfs2_revoke_lops;
sdp->sd_log_num_revoke++;
atomic_inc(&gl->gl_revokes);

View File

@ -258,6 +258,7 @@ void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int
struct address_space *mapping = bh->b_page->mapping;
struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
struct gfs2_bufdata *bd = bh->b_private;
int was_pinned = 0;
if (test_clear_buffer_pinned(bh)) {
trace_gfs2_pin(bd, 0);
@ -273,12 +274,16 @@ void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int
tr->tr_num_databuf_rm++;
}
tr->tr_touched = 1;
was_pinned = 1;
brelse(bh);
}
if (bd) {
spin_lock(&sdp->sd_ail_lock);
if (bd->bd_tr) {
gfs2_trans_add_revoke(sdp, bd);
} else if (was_pinned) {
bh->b_private = NULL;
kmem_cache_free(gfs2_bufdata_cachep, bd);
}
spin_unlock(&sdp->sd_ail_lock);
}

View File

@ -1366,8 +1366,18 @@ static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags,
if (IS_ERR(s))
goto error_bdev;
if (s->s_root)
if (s->s_root) {
/*
* s_umount nests inside bd_mutex during
* __invalidate_device(). blkdev_put() acquires
* bd_mutex and can't be called under s_umount. Drop
* s_umount temporarily. This is safe as we're
* holding an active reference.
*/
up_write(&s->s_umount);
blkdev_put(bdev, mode);
down_write(&s->s_umount);
}
memset(&args, 0, sizeof(args));
args.ar_quota = GFS2_QUOTA_DEFAULT;