NTFS: 2.1.28 - Fix deadlock reported by Sergey Vlasov due to ntfs_put_inode().

- Fix deadlock in fs/ntfs/inode.c::ntfs_put_inode().  Thanks to Sergey
  Vlasov for the report and detailed analysis of the deadlock.  The fix
  involved getting rid of ntfs_put_inode() altogether and hence NTFS no
  longer has a ->put_inode super operation.

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

6 files changed, 52 insertions, 84 deletions

diff --git a/Documentation/filesystems/ntfs.txt b/Documentation/filesystems/ntfs.txt
index 13ba649bda75..81779068b09b 100644
--- a/Documentation/filesystems/ntfs.txt
+++ b/Documentation/filesystems/ntfs.txt
@@ -457,6 +457,8 @@ ChangeLog
 
 Note, a technical ChangeLog aimed at kernel hackers is in fs/ntfs/ChangeLog.
 
+2.1.28:
+        - Fix a deadlock.
 2.1.27:
         - Implement page migration support so the kernel can move memory used
           by NTFS files and directories around for management purposes.
diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog
index 35cc4b1d60f7..af4ef808fa94 100644
--- a/fs/ntfs/ChangeLog
+++ b/fs/ntfs/ChangeLog
@@ -17,6 +17,13 @@ ToDo/Notes:
           happen is unclear however so it is worth waiting until someone hits
           the problem.
 
+2.1.28 - Fix a deadlock.
+
+        - Fix deadlock in fs/ntfs/inode.c::ntfs_put_inode().  Thanks to Sergey
+          Vlasov for the report and detailed analysis of the deadlock.  The fix
+          involved getting rid of ntfs_put_inode() altogether and hence NTFS no
+          longer has a ->put_inode super operation.
+
 2.1.27 - Various bug fixes and cleanups.
 
         - Fix two compiler warnings on Alpha.  Thanks to Andrew Morton for
diff --git a/fs/ntfs/dir.c b/fs/ntfs/dir.c
index 8296c29ae3b8..74f99a6a369b 100644
--- a/fs/ntfs/dir.c
+++ b/fs/ntfs/dir.c
@@ -1,7 +1,7 @@
 /**
  * dir.c - NTFS kernel directory operations. Part of the Linux-NTFS project.
  *
- * Copyright (c) 2001-2005 Anton Altaparmakov
+ * Copyright (c) 2001-2007 Anton Altaparmakov
  * Copyright (c) 2002 Richard Russon
  *
  * This program/include file is free software; you can redistribute it and/or
@@ -1249,16 +1249,12 @@ skip_index_root:
         /* Get the offset into the index allocation attribute. */
         ia_pos = (s64)fpos - vol->mft_record_size;
         ia_mapping = vdir->i_mapping;
-        bmp_vi = ndir->itype.index.bmp_ino;
-        if (unlikely(!bmp_vi)) {
-                ntfs_debug("Inode 0x%lx, regetting index bitmap.", vdir->i_ino);
-                bmp_vi = ntfs_attr_iget(vdir, AT_BITMAP, I30, 4);
-                if (IS_ERR(bmp_vi)) {
-                        ntfs_error(sb, "Failed to get bitmap attribute.");
-                        err = PTR_ERR(bmp_vi);
-                        goto err_out;
-                }
-                ndir->itype.index.bmp_ino = bmp_vi;
+        ntfs_debug("Inode 0x%lx, getting index bitmap.", vdir->i_ino);
+        bmp_vi = ntfs_attr_iget(vdir, AT_BITMAP, I30, 4);
+        if (IS_ERR(bmp_vi)) {
+                ntfs_error(sb, "Failed to get bitmap attribute.");
+                err = PTR_ERR(bmp_vi);
+                goto err_out;
         }
         bmp_mapping = bmp_vi->i_mapping;
         /* Get the starting bitmap bit position and sanity check it. */
@@ -1266,7 +1262,7 @@ skip_index_root:
         if (unlikely(bmp_pos >> 3 >= i_size_read(bmp_vi))) {
                 ntfs_error(sb, "Current index allocation position exceeds "
                                 "index bitmap size.");
-                goto err_out;
+                goto iput_err_out;
         }
         /* Get the starting bit position in the current bitmap page. */
         cur_bmp_pos = bmp_pos & ((PAGE_CACHE_SIZE * 8) - 1);
@@ -1282,7 +1278,7 @@ get_next_bmp_page:
                 ntfs_error(sb, "Reading index bitmap failed.");
                 err = PTR_ERR(bmp_page);
                 bmp_page = NULL;
-                goto err_out;
+                goto iput_err_out;
         }
         bmp = (u8*)page_address(bmp_page);
         /* Find next index block in use. */
@@ -1429,6 +1425,7 @@ find_next_index_buffer:
                         /* @ia_page is already unlocked in this case. */
                         ntfs_unmap_page(ia_page);
                         ntfs_unmap_page(bmp_page);
+                        iput(bmp_vi);
                         goto abort;
                 }
         }
@@ -1439,6 +1436,7 @@ unm_EOD:
                 ntfs_unmap_page(ia_page);
         }
         ntfs_unmap_page(bmp_page);
+        iput(bmp_vi);
 EOD:
         /* We are finished, set fpos to EOD. */
         fpos = i_size + vol->mft_record_size;
@@ -1455,8 +1453,11 @@ done:
         filp->f_pos = fpos;
         return 0;
 err_out:
-        if (bmp_page)
+        if (bmp_page) {
                 ntfs_unmap_page(bmp_page);
+iput_err_out:
+                iput(bmp_vi);
+        }
         if (ia_page) {
                 unlock_page(ia_page);
                 ntfs_unmap_page(ia_page);
@@ -1529,14 +1530,22 @@ static int ntfs_dir_open(struct inode *vi, struct file *filp)
 static int ntfs_dir_fsync(struct file *filp, struct dentry *dentry,
                 int datasync)
 {
-        struct inode *vi = dentry->d_inode;
-        ntfs_inode *ni = NTFS_I(vi);
+        struct inode *bmp_vi, *vi = dentry->d_inode;
         int err, ret;
+        ntfs_attr na;
 
         ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
         BUG_ON(!S_ISDIR(vi->i_mode));
-        if (NInoIndexAllocPresent(ni) && ni->itype.index.bmp_ino)
-                write_inode_now(ni->itype.index.bmp_ino, !datasync);
+        /* If the bitmap attribute inode is in memory sync it, too. */
+        na.mft_no = vi->i_ino;
+        na.type = AT_BITMAP;
+        na.name = I30;
+        na.name_len = 4;
+        bmp_vi = ilookup5(vi->i_sb, vi->i_ino, (test_t)ntfs_test_inode, &na);
+        if (bmp_vi) {
+                write_inode_now(bmp_vi, !datasync);
+                iput(bmp_vi);
+        }
         ret = ntfs_write_inode(vi, 1);
         write_inode_now(vi, !datasync);
         err = sync_blockdev(vi->i_sb->s_bdev);
diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
index 247989891b4b..f8bf8da67ee8 100644
--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -1,7 +1,7 @@
 /**
  * inode.c - NTFS kernel inode handling. Part of the Linux-NTFS project.
  *
- * Copyright (c) 2001-2006 Anton Altaparmakov
+ * Copyright (c) 2001-2007 Anton Altaparmakov
  *
  * This program/include file is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as published
@@ -95,7 +95,7 @@ int ntfs_test_inode(struct inode *vi, ntfs_attr *na)
  * If initializing the normal file/directory inode, set @na->type to AT_UNUSED.
  * In that case, @na->name and @na->name_len should be set to NULL and 0,
  * respectively. Although that is not strictly necessary as
- * ntfs_read_inode_locked() will fill them in later.
+ * ntfs_read_locked_inode() will fill them in later.
  *
  * Return 0 on success and -errno on error.
  *
@@ -171,8 +171,8 @@ static int ntfs_read_locked_index_inode(struct inode *base_vi,
 struct inode *ntfs_iget(struct super_block *sb, unsigned long mft_no)
 {
         struct inode *vi;
-        ntfs_attr na;
         int err;
+        ntfs_attr na;
 
         na.mft_no = mft_no;
         na.type = AT_UNUSED;
@@ -229,8 +229,8 @@ struct inode *ntfs_attr_iget(struct inode *base_vi, ATTR_TYPE type,
                 ntfschar *name, u32 name_len)
 {
         struct inode *vi;
-        ntfs_attr na;
         int err;
+        ntfs_attr na;
 
         /* Make sure no one calls ntfs_attr_iget() for indices. */
         BUG_ON(type == AT_INDEX_ALLOCATION);
@@ -287,8 +287,8 @@ struct inode *ntfs_index_iget(struct inode *base_vi, ntfschar *name,
                 u32 name_len)
 {
         struct inode *vi;
-        ntfs_attr na;
         int err;
+        ntfs_attr na;
 
         na.mft_no = base_vi->i_ino;
         na.type = AT_INDEX_ALLOCATION;
@@ -402,7 +402,6 @@ void __ntfs_init_inode(struct super_block *sb, ntfs_inode *ni)
         ntfs_init_runlist(&ni->attr_list_rl);
         lockdep_set_class(&ni->attr_list_rl.lock,
                                 &attr_list_rl_lock_class);
-        ni->itype.index.bmp_ino = NULL;
         ni->itype.index.block_size = 0;
         ni->itype.index.vcn_size = 0;
         ni->itype.index.collation_rule = 0;
@@ -546,6 +545,7 @@ static int ntfs_read_locked_inode(struct inode *vi)
 {
         ntfs_volume *vol = NTFS_SB(vi->i_sb);
         ntfs_inode *ni;
+        struct inode *bvi;
         MFT_RECORD *m;
         ATTR_RECORD *a;
         STANDARD_INFORMATION *si;
@@ -780,7 +780,6 @@ skip_attr_list_load:
          */
         if (S_ISDIR(vi->i_mode)) {
                 loff_t bvi_size;
-                struct inode *bvi;
                 ntfs_inode *bni;
                 INDEX_ROOT *ir;
                 u8 *ir_end, *index_end;
@@ -985,13 +984,12 @@ skip_attr_list_load:
                         err = PTR_ERR(bvi);
                         goto unm_err_out;
                 }
-                ni->itype.index.bmp_ino = bvi;
                 bni = NTFS_I(bvi);
                 if (NInoCompressed(bni) || NInoEncrypted(bni) ||
                                 NInoSparse(bni)) {
                         ntfs_error(vi->i_sb, "$BITMAP attribute is compressed "
                                         "and/or encrypted and/or sparse.");
-                        goto unm_err_out;
+                        goto iput_unm_err_out;
                 }
                 /* Consistency check bitmap size vs. index allocation size. */
                 bvi_size = i_size_read(bvi);
@@ -1000,8 +998,10 @@ skip_attr_list_load:
                         ntfs_error(vi->i_sb, "Index bitmap too small (0x%llx) "
                                         "for index allocation (0x%llx).",
                                         bvi_size << 3, vi->i_size);
-                        goto unm_err_out;
+                        goto iput_unm_err_out;
                 }
+                /* No longer need the bitmap attribute inode. */
+                iput(bvi);
 skip_large_dir_stuff:
                 /* Setup the operations for this inode. */
                 vi->i_op = &ntfs_dir_inode_ops;
@@ -1176,7 +1176,8 @@ no_data_attr_special_case:
                 vi->i_blocks = ni->allocated_size >> 9;
         ntfs_debug("Done.");
         return 0;
-
+iput_unm_err_out:
+        iput(bvi);
 unm_err_out:
         if (!err)
                 err = -EIO;
@@ -1697,7 +1698,7 @@ static int ntfs_read_locked_index_inode(struct inode *base_vi, struct inode *vi)
                                 vi->i_size);
                 goto iput_unm_err_out;
         }
-        ni->itype.index.bmp_ino = bvi;
+        iput(bvi);
 skip_large_index_stuff:
         /* Setup the operations for this index inode. */
         vi->i_op = NULL;
@@ -1714,7 +1715,6 @@ skip_large_index_stuff:
 
         ntfs_debug("Done.");
         return 0;
-
 iput_unm_err_out:
         iput(bvi);
 unm_err_out:
@@ -2191,37 +2191,6 @@ err_out:
         return -1;
 }
 
-/**
- * ntfs_put_inode - handler for when the inode reference count is decremented
- * @vi:         vfs inode
- *
- * The VFS calls ntfs_put_inode() every time the inode reference count (i_count)
- * is about to be decremented (but before the decrement itself.
- *
- * If the inode @vi is a directory with two references, one of which is being
- * dropped, we need to put the attribute inode for the directory index bitmap,
- * if it is present, otherwise the directory inode would remain pinned for
- * ever.
- */
-void ntfs_put_inode(struct inode *vi)
-{
-        if (S_ISDIR(vi->i_mode) && atomic_read(&vi->i_count) == 2) {
-                ntfs_inode *ni = NTFS_I(vi);
-                if (NInoIndexAllocPresent(ni)) {
-                        struct inode *bvi = NULL;
-                        mutex_lock(&vi->i_mutex);
-                        if (atomic_read(&vi->i_count) == 2) {
-                                bvi = ni->itype.index.bmp_ino;
-                                if (bvi)
-                                        ni->itype.index.bmp_ino = NULL;
-                        }
-                        mutex_unlock(&vi->i_mutex);
-                        if (bvi)
-                                iput(bvi);
-                }
-        }
-}
-
 static void __ntfs_clear_inode(ntfs_inode *ni)
 {
         /* Free all alocated memory. */
@@ -2287,18 +2256,6 @@ void ntfs_clear_big_inode(struct inode *vi)
 {
         ntfs_inode *ni = NTFS_I(vi);
 
-        /*
-         * If the inode @vi is an index inode we need to put the attribute
-         * inode for the index bitmap, if it is present, otherwise the index
-         * inode would disappear and the attribute inode for the index bitmap
-         * would no longer be referenced from anywhere and thus it would remain
-         * pinned for ever.
-         */
-        if (NInoAttr(ni) && (ni->type == AT_INDEX_ALLOCATION) &&
-                        NInoIndexAllocPresent(ni) && ni->itype.index.bmp_ino) {
-                iput(ni->itype.index.bmp_ino);
-                ni->itype.index.bmp_ino = NULL;
-        }
 #ifdef NTFS_RW
         if (NInoDirty(ni)) {
                 bool was_bad = (is_bad_inode(vi));
diff --git a/fs/ntfs/inode.h b/fs/ntfs/inode.h
index f088291e017c..117eaf8032a3 100644
--- a/fs/ntfs/inode.h
+++ b/fs/ntfs/inode.h
@@ -2,7 +2,7 @@
  * inode.h - Defines for inode structures NTFS Linux kernel driver. Part of
  *           the Linux-NTFS project.
  *
- * Copyright (c) 2001-2005 Anton Altaparmakov
+ * Copyright (c) 2001-2007 Anton Altaparmakov
  * Copyright (c) 2002 Richard Russon
  *
  * This program/include file is free software; you can redistribute it and/or
@@ -101,8 +101,6 @@ struct _ntfs_inode {
         runlist attr_list_rl;   /* Run list for the attribute list value. */
         union {
                 struct { /* It is a directory, $MFT, or an index inode. */
-                        struct inode *bmp_ino;  /* Attribute inode for the
-                                                   index $BITMAP. */
                         u32 block_size;         /* Size of an index block. */
                         u32 vcn_size;           /* Size of a vcn in this
                                                    index. */
@@ -300,8 +298,6 @@ extern void ntfs_clear_extent_inode(ntfs_inode *ni);
 
 extern int ntfs_read_inode_mount(struct inode *vi);
 
-extern void ntfs_put_inode(struct inode *vi);
-
 extern int ntfs_show_options(struct seq_file *sf, struct vfsmount *mnt);
 
 #ifdef NTFS_RW
diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
index 03a391ac7145..babf94d90def 100644
--- a/fs/ntfs/super.c
+++ b/fs/ntfs/super.c
@@ -1,7 +1,7 @@
 /*
  * super.c - NTFS kernel super block handling. Part of the Linux-NTFS project.
  *
- * Copyright (c) 2001-2006 Anton Altaparmakov
+ * Copyright (c) 2001-2007 Anton Altaparmakov
  * Copyright (c) 2001,2002 Richard Russon
  *
  * This program/include file is free software; you can redistribute it and/or
@@ -2702,9 +2702,6 @@ static int ntfs_statfs(struct dentry *dentry, struct kstatfs *sfs)
 static struct super_operations ntfs_sops = {
         .alloc_inode    = ntfs_alloc_big_inode,   /* VFS: Allocate new inode. */
         .destroy_inode  = ntfs_destroy_big_inode, /* VFS: Deallocate inode. */
-        .put_inode      = ntfs_put_inode,         /* VFS: Called just before
-                                                     the inode reference count
-                                                     is decreased. */
 #ifdef NTFS_RW
         //.dirty_inode  = NULL,                 /* VFS: Called from
         //                                         __mark_inode_dirty(). */
@@ -3261,7 +3258,7 @@ static void __exit exit_ntfs_fs(void)
 }
 
 MODULE_AUTHOR("Anton Altaparmakov <aia21@cantab.net>");
-MODULE_DESCRIPTION("NTFS 1.2/3.x driver - Copyright (c) 2001-2006 Anton Altaparmakov");
+MODULE_DESCRIPTION("NTFS 1.2/3.x driver - Copyright (c) 2001-2007 Anton Altaparmakov");
 MODULE_VERSION(NTFS_VERSION);
 MODULE_LICENSE("GPL");
 #ifdef DEBUG