From: Robert S Peterson <rpeterso@redhat.com>
Date: Thu, 07 Apr 2011 16:14:50 -0000
Subject: [fs] gfs2: fix filesystem hang caused by incorrect lock order
Message-id: <1384613617.798723.1302192890092.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com>
Patchwork-id: 35389
O-Subject: [RHEL5.6.z Patch][3 of 3] Bug 688855 - GFS2 filesystem hang caused
by incorrect lock order
Bugzilla: 688855
RH-Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Hi,
Here is the third patch for bug #688855. It is already
upstream and a nearly identical patch was posted for RHEL5.7
for bz 656032. All three have been tested at customer sites and
received positive feedback.
This patch fixes a deadlock in GFS2 where two processes are trying
to reclaim an unlinked dinode:
One holds the inode glock and calls gfs2_lookup_by_inum trying to look
up the inode, which it can't, due to I_FREEING. The other has set
I_FREEING from vfs and is at the beginning of gfs2_delete_inode
waiting for the glock, which is held by the first. The solution is to
add a new non_block parameter to the gfs2_iget function that causes it
to return -ENOENT if the inode is being freed.
rhbz#688855
Regards,
Bob Peterson
Red Hat File Systems
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
--
commit 970bd969357b839230dff2adbc484f41739ba402
Author: Bob Peterson <rpeterso@redhat.com>
Date: Fri Mar 18 08:28:47 2011 -0500
GFS2 filesystem hang caused by incorrect lock order
This patch fixes a deadlock in GFS2 where two processes are trying
to reclaim an unlinked dinode:
One holds the inode glock and calls gfs2_lookup_by_inum trying to look
up the inode, which it can't, due to I_FREEING. The other has set
I_FREEING from vfs and is at the beginning of gfs2_delete_inode
waiting for the glock, which is held by the first. The solution is to
add a new non_block parameter to the gfs2_iget function that causes it
to return -ENOENT if the inode is being freed.
rhbz#688855
diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index 47e98b4..444fc71 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -1500,7 +1500,7 @@ struct inode *gfs2_dir_search(struct inode *dir, const struct qstr *name)
inode = gfs2_inode_lookup(dir->i_sb,
be16_to_cpu(dent->de_type),
be64_to_cpu(dent->de_inum.no_addr),
- be64_to_cpu(dent->de_inum.no_formal_ino));
+ be64_to_cpu(dent->de_inum.no_formal_ino), 0);
brelse(bh);
return inode;
}
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 8eac5af..034afaf 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -42,24 +42,38 @@ struct gfs2_inum_range_host {
u64 ir_length;
};
+struct gfs2_skip_data {
+ u64 no_addr;
+ int skipped;
+ int non_block;
+};
+
static int iget_test(struct inode *inode, void *opaque)
{
struct gfs2_inode *ip = GFS2_I(inode);
- u64 *no_addr = opaque;
+ struct gfs2_skip_data *data = opaque;
- if (ip->i_no_addr == *no_addr && test_bit(GIF_USER, &ip->i_flags))
+ if (ip->i_no_addr == data->no_addr &&
+ test_bit(GIF_USER, &ip->i_flags)) {
+ if (data->non_block &&
+ inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
+ data->skipped = 1;
+ return 0;
+ }
return 1;
-
+ }
return 0;
}
static int iget_set(struct inode *inode, void *opaque)
{
struct gfs2_inode *ip = GFS2_I(inode);
- u64 *no_addr = opaque;
+ struct gfs2_skip_data *data = opaque;
- inode->i_ino = (unsigned long)*no_addr;
- ip->i_no_addr = *no_addr;
+ if (data->skipped)
+ return -ENOENT;
+ inode->i_ino = (unsigned long)(data->no_addr);
+ ip->i_no_addr = data->no_addr;
set_bit(GIF_USER, &ip->i_flags);
return 0;
}
@@ -67,13 +81,24 @@ static int iget_set(struct inode *inode, void *opaque)
struct inode *gfs2_ilookup(struct super_block *sb, u64 no_addr)
{
unsigned long hash = (unsigned long)no_addr;
- return ilookup5(sb, hash, iget_test, &no_addr);
+ struct gfs2_skip_data data;
+
+ data.no_addr = no_addr;
+ data.skipped = 0;
+ data.non_block = 0;
+ return ilookup5(sb, hash, iget_test, &data);
}
-static struct inode *gfs2_iget(struct super_block *sb, u64 no_addr)
+static struct inode *gfs2_iget(struct super_block *sb, u64 no_addr,
+ int non_block)
{
+ struct gfs2_skip_data data;
unsigned long hash = (unsigned long)no_addr;
- return iget5_locked(sb, hash, iget_test, iget_set, &no_addr);
+
+ data.no_addr = no_addr;
+ data.skipped = 0;
+ data.non_block = non_block;
+ return iget5_locked(sb, hash, iget_test, iget_set, &data);
}
/**
@@ -114,19 +139,20 @@ static void gfs2_set_iop(struct inode *inode)
* @sb: The super block
* @no_addr: The inode number
* @type: The type of the inode
+ * non_block: Can we block on inodes that are being freed?
*
* Returns: A VFS inode, or an error
*/
struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned int type,
- u64 no_addr, u64 no_formal_ino)
+ u64 no_addr, u64 no_formal_ino, int non_block)
{
struct inode *inode;
struct gfs2_inode *ip;
struct gfs2_glock *io_gl = NULL;
int error;
- inode = gfs2_iget(sb, no_addr);
+ inode = gfs2_iget(sb, no_addr, non_block);
ip = GFS2_I(inode);
if (!inode)
@@ -203,7 +229,7 @@ struct inode *gfs2_lookup_by_inum(struct gfs2_sbd *sdp, u64 no_addr,
if (error)
goto fail;
- inode = gfs2_inode_lookup(sb, DT_UNKNOWN, no_addr, 0);
+ inode = gfs2_inode_lookup(sb, DT_UNKNOWN, no_addr, 0, 1);
if (IS_ERR(inode))
goto fail;
@@ -993,7 +1019,7 @@ struct inode *gfs2_createi(struct gfs2_holder *ghs, const struct qstr *name,
goto fail_gunlock2;
inode = gfs2_inode_lookup(dir->i_sb, IF2DT(mode), inum.no_addr,
- inum.no_formal_ino);
+ inum.no_formal_ino, 0);
if (IS_ERR(inode))
goto fail_gunlock2;
diff --git a/fs/gfs2/inode.h b/fs/gfs2/inode.h
index 3d24fa3..e6762d9 100644
--- a/fs/gfs2/inode.h
+++ b/fs/gfs2/inode.h
@@ -75,7 +75,7 @@ static inline void gfs2_inum_out(const struct gfs2_inode *ip,
void gfs2_inode_attr_in(struct gfs2_inode *ip);
struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned type,
- u64 no_addr, u64 no_formal_ino);
+ u64 no_addr, u64 no_formal_ino, int non_block);
extern struct inode *gfs2_lookup_by_inum(struct gfs2_sbd *sdp, u64 no_addr,
u64 *no_formal_ino,
unsigned int blktype);
diff --git a/fs/gfs2/ops_export.c b/fs/gfs2/ops_export.c
index d45765d..9bf0342 100644
--- a/fs/gfs2/ops_export.c
+++ b/fs/gfs2/ops_export.c
@@ -198,15 +198,17 @@ static struct dentry *gfs2_get_dentry(struct super_block *sb, void *inum_obj)
iput(inode);
return ERR_PTR(-ESTALE);
}
- goto out_inode;
+ } else {
+ inode = gfs2_lookup_by_inum(sdp, inum->no_addr,
+ &inum->no_formal_ino,
+ GFS2_BLKST_DINODE);
+ if (inode == ERR_PTR(-ENOENT))
+ inode = gfs2_ilookup(sb, inum->no_addr);
}
- inode = gfs2_lookup_by_inum(sdp, inum->no_addr, &inum->no_formal_ino,
- GFS2_BLKST_DINODE);
if (IS_ERR(inode))
return ERR_CAST(inode);
-out_inode:
dentry = d_alloc_anon(inode);
if (!dentry) {
iput(inode);
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index d4b7de4..75dbe03 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -499,7 +499,7 @@ static int gfs2_lookup_root(struct super_block *sb, struct dentry **dptr,
struct dentry *dentry;
struct inode *inode;
- inode = gfs2_inode_lookup(sb, DT_DIR, no_addr, 0);
+ inode = gfs2_inode_lookup(sb, DT_DIR, no_addr, 0, 0);
if (IS_ERR(inode)) {
fs_err(sdp, "can't read in %s inode: %ld\n", name, PTR_ERR(inode));
return PTR_ERR(inode);
