5 files changed, 74 insertions, 41 deletions

diff --git a/fs/jfs/inode.c b/fs/jfs/inode.c
index f5719117edfe..e285022f006c 100644
--- a/fs/jfs/inode.c
+++ b/fs/jfs/inode.c
@@ -182,9 +182,9 @@ int jfs_get_block(struct inode *ip, sector_t lblock,
          * Take appropriate lock on inode
          */
         if (create)
-                IWRITE_LOCK(ip);
+                IWRITE_LOCK(ip, RDWRLOCK_NORMAL);
         else
-                IREAD_LOCK(ip);
+                IREAD_LOCK(ip, RDWRLOCK_NORMAL);
 
         if (((lblock64 << ip->i_sb->s_blocksize_bits) < ip->i_size) &&
             (!xtLookup(ip, lblock64, xlen, &xflag, &xaddr, &xlen, 0)) &&
@@ -359,7 +359,7 @@ void jfs_truncate(struct inode *ip)
 
         nobh_truncate_page(ip->i_mapping, ip->i_size);
 
-        IWRITE_LOCK(ip);
+        IWRITE_LOCK(ip, RDWRLOCK_NORMAL);
         jfs_truncate_nolock(ip, ip->i_size);
         IWRITE_UNLOCK(ip);
 }
diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index 23546c8fd48b..82b0544bd76d 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -337,7 +337,7 @@ int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
         struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
         struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
 
-        IREAD_LOCK(ipbmap);
+        IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
 
         /* block to be freed better be within the mapsize. */
         if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) {
@@ -733,7 +733,7 @@ int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
          * allocation group size, try to allocate anywhere.
          */
         if (l2nb > bmp->db_agl2size) {
-                IWRITE_LOCK(ipbmap);
+                IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
 
                 rc = dbAllocAny(bmp, nblocks, l2nb, results);
 
@@ -774,7 +774,7 @@ int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
          * the hint using a tiered strategy.
          */
         if (nblocks <= BPERDMAP) {
-                IREAD_LOCK(ipbmap);
+                IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
 
                 /* get the buffer for the dmap containing the hint.
                  */
@@ -844,7 +844,7 @@ int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
         /* try to satisfy the allocation request with blocks within
          * the same allocation group as the hint.
          */
-        IWRITE_LOCK(ipbmap);
+        IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
         if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC)
                 goto write_unlock;
 
@@ -856,7 +856,7 @@ int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
          * Let dbNextAG recommend a preferred allocation group
          */
         agno = dbNextAG(ipbmap);
-        IWRITE_LOCK(ipbmap);
+        IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
 
         /* Try to allocate within this allocation group.  if that fails, try to
          * allocate anywhere in the map.
@@ -900,7 +900,7 @@ int dbAllocExact(struct inode *ip, s64 blkno, int nblocks)
         s64 lblkno;
         struct metapage *mp;
 
-        IREAD_LOCK(ipbmap);
+        IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
 
         /*
          * validate extent request:
@@ -1050,7 +1050,7 @@ static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
          */
         extblkno = lastblkno + 1;
 
-        IREAD_LOCK(ipbmap);
+        IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
 
         /* better be within the file system */
         bmp = sbi->bmap;
@@ -3116,7 +3116,7 @@ int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks)
         struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
         struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
 
-        IREAD_LOCK(ipbmap);
+        IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
 
         /* block to be allocated better be within the mapsize. */
         ASSERT(nblocks <= bmp->db_mapsize - blkno);
diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c
index 53f63b47a6d3..aa5124b643b1 100644
--- a/fs/jfs/jfs_imap.c
+++ b/fs/jfs/jfs_imap.c
@@ -331,7 +331,7 @@ int diRead(struct inode *ip)
 
         /* read the iag */
         imap = JFS_IP(ipimap)->i_imap;
-        IREAD_LOCK(ipimap);
+        IREAD_LOCK(ipimap, RDWRLOCK_IMAP);
         rc = diIAGRead(imap, iagno, &mp);
         IREAD_UNLOCK(ipimap);
         if (rc) {
@@ -920,7 +920,7 @@ int diFree(struct inode *ip)
         /* Obtain read lock in imap inode.  Don't release it until we have
          * read all of the IAG's that we are going to.
          */
-        IREAD_LOCK(ipimap);
+        IREAD_LOCK(ipimap, RDWRLOCK_IMAP);
 
         /* read the iag.
          */
@@ -1415,7 +1415,7 @@ int diAlloc(struct inode *pip, bool dir, struct inode *ip)
         AG_LOCK(imap, agno);
 
         /* Get read lock on imap inode */
-        IREAD_LOCK(ipimap);
+        IREAD_LOCK(ipimap, RDWRLOCK_IMAP);
 
         /* get the iag number and read the iag */
         iagno = INOTOIAG(inum);
@@ -1808,7 +1808,7 @@ static int diAllocIno(struct inomap * imap, int agno, struct inode *ip)
                 return -ENOSPC;
 
         /* obtain read lock on imap inode */
-        IREAD_LOCK(imap->im_ipimap);
+        IREAD_LOCK(imap->im_ipimap, RDWRLOCK_IMAP);
 
         /* read the iag at the head of the list.
          */
@@ -1946,7 +1946,7 @@ static int diAllocExt(struct inomap * imap, int agno, struct inode *ip)
         } else {
                 /* read the iag.
                  */
-                IREAD_LOCK(imap->im_ipimap);
+                IREAD_LOCK(imap->im_ipimap, RDWRLOCK_IMAP);
                 if ((rc = diIAGRead(imap, iagno, &mp))) {
                         IREAD_UNLOCK(imap->im_ipimap);
                         jfs_error(ip->i_sb, "diAllocExt: error reading iag");
@@ -2509,7 +2509,7 @@ diNewIAG(struct inomap * imap, int *iagnop, int agno, struct metapage ** mpp)
                  */
 
                 /* acquire inode map lock */
-                IWRITE_LOCK(ipimap);
+                IWRITE_LOCK(ipimap, RDWRLOCK_IMAP);
 
                 if (ipimap->i_size >> L2PSIZE != imap->im_nextiag + 1) {
                         IWRITE_UNLOCK(ipimap);
@@ -2648,7 +2648,7 @@ diNewIAG(struct inomap * imap, int *iagnop, int agno, struct metapage ** mpp)
         }
 
         /* obtain read lock on map */
-        IREAD_LOCK(ipimap);
+        IREAD_LOCK(ipimap, RDWRLOCK_IMAP);
 
         /* read the iag */
         if ((rc = diIAGRead(imap, iagno, &mp))) {
@@ -2779,7 +2779,7 @@ diUpdatePMap(struct inode *ipimap,
                 return -EIO;
         }
         /* read the iag */
-        IREAD_LOCK(ipimap);
+        IREAD_LOCK(ipimap, RDWRLOCK_IMAP);
         rc = diIAGRead(imap, iagno, &mp);
         IREAD_UNLOCK(ipimap);
         if (rc)
diff --git a/fs/jfs/jfs_incore.h b/fs/jfs/jfs_incore.h
index 94005584445a..8f453eff3c83 100644
--- a/fs/jfs/jfs_incore.h
+++ b/fs/jfs/jfs_incore.h
@@ -109,9 +109,11 @@ struct jfs_inode_info {
 
 #define JFS_ACL_NOT_CACHED ((void *)-1)
 
-#define IREAD_LOCK(ip)          down_read(&JFS_IP(ip)->rdwrlock)
+#define IREAD_LOCK(ip, subclass) \
+        down_read_nested(&JFS_IP(ip)->rdwrlock, subclass)
 #define IREAD_UNLOCK(ip)        up_read(&JFS_IP(ip)->rdwrlock)
-#define IWRITE_LOCK(ip)         down_write(&JFS_IP(ip)->rdwrlock)
+#define IWRITE_LOCK(ip, subclass) \
+        down_write_nested(&JFS_IP(ip)->rdwrlock, subclass)
 #define IWRITE_UNLOCK(ip)       up_write(&JFS_IP(ip)->rdwrlock)
 
 /*
@@ -127,6 +129,29 @@ enum cflags {
         COMMIT_Synclist,        /* metadata pages on group commit synclist */
 };
 
+/*
+ * commit_mutex nesting subclasses:
+ */
+enum commit_mutex_class
+{
+        COMMIT_MUTEX_PARENT,
+        COMMIT_MUTEX_CHILD,
+        COMMIT_MUTEX_SECOND_PARENT,     /* Renaming */
+        COMMIT_MUTEX_VICTIM             /* Inode being unlinked due to rename */
+};
+
+/*
+ * rdwrlock subclasses:
+ * The dmap inode may be locked while a normal inode or the imap inode are
+ * locked.
+ */
+enum rdwrlock_class
+{
+        RDWRLOCK_NORMAL,
+        RDWRLOCK_IMAP,
+        RDWRLOCK_DMAP
+};
+
 #define set_cflag(flag, ip)     set_bit(flag, &(JFS_IP(ip)->cflag))
 #define clear_cflag(flag, ip)   clear_bit(flag, &(JFS_IP(ip)->cflag))
 #define test_cflag(flag, ip)    test_bit(flag, &(JFS_IP(ip)->cflag))
diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index a6a8c16c872c..7ab47561b68d 100644
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -104,8 +104,8 @@ static int jfs_create(struct inode *dip, struct dentry *dentry, int mode,
 
         tid = txBegin(dip->i_sb, 0);
 
-        mutex_lock(&JFS_IP(dip)->commit_mutex);
-        mutex_lock(&JFS_IP(ip)->commit_mutex);
+        mutex_lock_nested(&JFS_IP(dip)->commit_mutex, COMMIT_MUTEX_PARENT);
+        mutex_lock_nested(&JFS_IP(ip)->commit_mutex, COMMIT_MUTEX_CHILD);
 
         rc = jfs_init_acl(tid, ip, dip);
         if (rc)
@@ -238,8 +238,8 @@ static int jfs_mkdir(struct inode *dip, struct dentry *dentry, int mode)
 
         tid = txBegin(dip->i_sb, 0);
 
-        mutex_lock(&JFS_IP(dip)->commit_mutex);
-        mutex_lock(&JFS_IP(ip)->commit_mutex);
+        mutex_lock_nested(&JFS_IP(dip)->commit_mutex, COMMIT_MUTEX_PARENT);
+        mutex_lock_nested(&JFS_IP(ip)->commit_mutex, COMMIT_MUTEX_CHILD);
 
         rc = jfs_init_acl(tid, ip, dip);
         if (rc)
@@ -365,8 +365,8 @@ static int jfs_rmdir(struct inode *dip, struct dentry *dentry)
 
         tid = txBegin(dip->i_sb, 0);
 
-        mutex_lock(&JFS_IP(dip)->commit_mutex);
-        mutex_lock(&JFS_IP(ip)->commit_mutex);
+        mutex_lock_nested(&JFS_IP(dip)->commit_mutex, COMMIT_MUTEX_PARENT);
+        mutex_lock_nested(&JFS_IP(ip)->commit_mutex, COMMIT_MUTEX_CHILD);
 
         iplist[0] = dip;
         iplist[1] = ip;
@@ -483,12 +483,12 @@ static int jfs_unlink(struct inode *dip, struct dentry *dentry)
         if ((rc = get_UCSname(&dname, dentry)))
                 goto out;
 
-        IWRITE_LOCK(ip);
+        IWRITE_LOCK(ip, RDWRLOCK_NORMAL);
 
         tid = txBegin(dip->i_sb, 0);
 
-        mutex_lock(&JFS_IP(dip)->commit_mutex);
-        mutex_lock(&JFS_IP(ip)->commit_mutex);
+        mutex_lock_nested(&JFS_IP(dip)->commit_mutex, COMMIT_MUTEX_PARENT);
+        mutex_lock_nested(&JFS_IP(ip)->commit_mutex, COMMIT_MUTEX_CHILD);
 
         iplist[0] = dip;
         iplist[1] = ip;
@@ -802,8 +802,8 @@ static int jfs_link(struct dentry *old_dentry,
 
         tid = txBegin(ip->i_sb, 0);
 
-        mutex_lock(&JFS_IP(dir)->commit_mutex);
-        mutex_lock(&JFS_IP(ip)->commit_mutex);
+        mutex_lock_nested(&JFS_IP(dir)->commit_mutex, COMMIT_MUTEX_PARENT);
+        mutex_lock_nested(&JFS_IP(ip)->commit_mutex, COMMIT_MUTEX_CHILD);
 
         /*
          * scan parent directory for entry/freespace
@@ -913,8 +913,8 @@ static int jfs_symlink(struct inode *dip, struct dentry *dentry,
 
         tid = txBegin(dip->i_sb, 0);
 
-        mutex_lock(&JFS_IP(dip)->commit_mutex);
-        mutex_lock(&JFS_IP(ip)->commit_mutex);
+        mutex_lock_nested(&JFS_IP(dip)->commit_mutex, COMMIT_MUTEX_PARENT);
+        mutex_lock_nested(&JFS_IP(ip)->commit_mutex, COMMIT_MUTEX_CHILD);
 
         rc = jfs_init_security(tid, ip, dip);
         if (rc)
@@ -1127,7 +1127,7 @@ static int jfs_rename(struct inode *old_dir, struct dentry *old_dentry,
                         goto out3;
                 }
         } else if (new_ip) {
-                IWRITE_LOCK(new_ip);
+                IWRITE_LOCK(new_ip, RDWRLOCK_NORMAL);
                 /* Init inode for quota operations. */
                 DQUOT_INIT(new_ip);
         }
@@ -1137,13 +1137,21 @@ static int jfs_rename(struct inode *old_dir, struct dentry *old_dentry,
          */
         tid = txBegin(new_dir->i_sb, 0);
 
-        mutex_lock(&JFS_IP(new_dir)->commit_mutex);
-        mutex_lock(&JFS_IP(old_ip)->commit_mutex);
+        /*
+         * How do we know the locking is safe from deadlocks?
+         * The vfs does the hard part for us.  Any time we are taking nested
+         * commit_mutexes, the vfs already has i_mutex held on the parent.
+         * Here, the vfs has already taken i_mutex on both old_dir and new_dir.
+         */
+        mutex_lock_nested(&JFS_IP(new_dir)->commit_mutex, COMMIT_MUTEX_PARENT);
+        mutex_lock_nested(&JFS_IP(old_ip)->commit_mutex, COMMIT_MUTEX_CHILD);
         if (old_dir != new_dir)
-                mutex_lock(&JFS_IP(old_dir)->commit_mutex);
+                mutex_lock_nested(&JFS_IP(old_dir)->commit_mutex,
+                                  COMMIT_MUTEX_SECOND_PARENT);
 
         if (new_ip) {
-                mutex_lock(&JFS_IP(new_ip)->commit_mutex);
+                mutex_lock_nested(&JFS_IP(new_ip)->commit_mutex,
+                                  COMMIT_MUTEX_VICTIM);
                 /*
                  * Change existing directory entry to new inode number
                  */
@@ -1357,8 +1365,8 @@ static int jfs_mknod(struct inode *dir, struct dentry *dentry,
 
         tid = txBegin(dir->i_sb, 0);
 
-        mutex_lock(&JFS_IP(dir)->commit_mutex);
-        mutex_lock(&JFS_IP(ip)->commit_mutex);
+        mutex_lock_nested(&JFS_IP(dir)->commit_mutex, COMMIT_MUTEX_PARENT);
+        mutex_lock_nested(&JFS_IP(ip)->commit_mutex, COMMIT_MUTEX_CHILD);
 
         rc = jfs_init_acl(tid, ip, dir);
         if (rc)