From: Bob Peterson rpeterso@redhat.com

[ Upstream commit 504a10d9e46bc37b23d0a1ae2f28973c8516e636 ]

On corrupt gfs2 file systems the evict code can try to reference the journal descriptor structure, jdesc, after it has been freed and set to NULL. The sequence of events is:

init_journal() ... fail_jindex: gfs2_jindex_free(sdp); <------frees journals, sets jdesc = NULL if (gfs2_holder_initialized(&ji_gh)) gfs2_glock_dq_uninit(&ji_gh); fail: iput(sdp->sd_jindex); <--references jdesc in evict_linked_inode evict() gfs2_evict_inode() evict_linked_inode() ret = gfs2_trans_begin(sdp, 0, sdp->sd_jdesc->jd_blocks); <------references the now freed/zeroed sd_jdesc pointer.

The call to gfs2_trans_begin is done because the truncate_inode_pages call can cause gfs2 events that require a transaction, such as removing journaled data (jdata) blocks from the journal.

This patch fixes the problem by adding a check for sdp->sd_jdesc to function gfs2_evict_inode. In theory, this should only happen to corrupt gfs2 file systems, when gfs2 detects the problem, reports it, then tries to evict all the system inodes it has read in up to that point.

Reported-by: Yang Lan lanyang0908@gmail.com Signed-off-by: Bob Peterson rpeterso@redhat.com Signed-off-by: Andreas Gruenbacher agruenba@redhat.com [DP: adjusted context] Signed-off-by: Dragos-Marian Panait dragos.panait@windriver.com --- fs/gfs2/super.c | 8 ++++++++ 1 file changed, 8 insertions(+)

diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index 56bfed0a5873..73290263402a 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -1575,6 +1575,14 @@ static void gfs2_evict_inode(struct inode *inode) if (inode->i_nlink || sb_rdonly(sb)) goto out;

+ /* + * In case of an incomplete mount, gfs2_evict_inode() may be called for + * system files without having an active journal to write to. In that + * case, skip the filesystem evict. + */ + if (!sdp->sd_jdesc) + goto out; + if (test_bit(GIF_ALLOC_FAILED, &ip->i_flags)) { BUG_ON(!gfs2_glock_is_locked_by_me(ip->i_gl)); gfs2_holder_mark_uninitialized(&gh);