src/patches/suse-2.6.27.39/patches.fixes/bug-531716_ocfs2-SLE11-dentry_lock_drop_flush.diff

   1 From: Jan Kara <jack@suse.cz>
   2 Subject: ocfs2: Fix deadlock on umount
   3 References: bnc#531716
   4 Patch-mainline: 2.6.32
   5
   6 In patch patches.fixes/ocfs2-push-out-dropping-of-dentry-lock-to-ocfs2_wq.patch
   7 we moved the dentry lock put process into ocfs2_wq. This causes problems during
   8 umount because ocfs2_wq can drop references to inodes while they are being
   9 invalidated by invalidate_inodes() causing all sorts of nasty things
  10 (invalidate_inodes() ending in an infinite loop, "Busy inodes after umount"
  11 messages etc.).
  12
  13 We fix the problem by stopping ocfs2_wq from doing any further releasing of
  14 inode references on the superblock being unmounted, wait until it finishes
  15 the current round of releasing and finally cleaning up all the references in
  16 dentry_lock_list from ocfs2_put_super().
  17
  18 The issue was tracked down by Tao Ma <tao.ma@oracle.com>.
  19
  20 Signed-off-by: Jan Kara <jack@suse.cz>
  21 Signed-off-by: Joel Becker <joel.becker@oracle.com>
  22
  23 diff -rupX /home/jack/.kerndiffexclude linux-2.6.27-SLE11_BRANCH/fs/ocfs2/dcache.c linux-2.6.27-SLE11_BRANCH-1-dentry_lock_drop//fs/ocfs2/dcache.c
  24 --- linux-2.6.27-SLE11_BRANCH/fs/ocfs2/dcache.c 2009-08-18 15:39:32.000000000 +0200
  25 +++ linux-2.6.27-SLE11_BRANCH-1-dentry_lock_drop//fs/ocfs2/dcache.c     2009-08-18 15:44:51.000000000 +0200
  26 @@ -295,22 +295,19 @@ out_attach:
  27         return ret;
  28  }
  29
  30 -static DEFINE_SPINLOCK(dentry_list_lock);
  31 +DEFINE_SPINLOCK(dentry_list_lock);
  32
  33  /* We limit the number of dentry locks to drop in one go. We have
  34   * this limit so that we don't starve other users of ocfs2_wq. */
  35  #define DL_INODE_DROP_COUNT 64
  36
  37  /* Drop inode references from dentry locks */
  38 -void ocfs2_drop_dl_inodes(struct work_struct *work)
  39 +static void __ocfs2_drop_dl_inodes(struct ocfs2_super *osb, int drop_count)
  40  {
  41 -       struct ocfs2_super *osb = container_of(work, struct ocfs2_super,
  42 -                                              dentry_lock_work);
  43         struct ocfs2_dentry_lock *dl;
  44 -       int drop_count = DL_INODE_DROP_COUNT;
  45
  46         spin_lock(&dentry_list_lock);
  47 -       while (osb->dentry_lock_list && drop_count--) {
  48 +       while (osb->dentry_lock_list && (drop_count < 0 || drop_count--)) {
  49                 dl = osb->dentry_lock_list;
  50                 osb->dentry_lock_list = dl->dl_next;
  51                 spin_unlock(&dentry_list_lock);
  52 @@ -318,11 +315,32 @@ void ocfs2_drop_dl_inodes(struct work_st
  53                 kfree(dl);
  54                 spin_lock(&dentry_list_lock);
  55         }
  56 -       if (osb->dentry_lock_list)
  57 +       spin_unlock(&dentry_list_lock);
  58 +}
  59 +
  60 +void ocfs2_drop_dl_inodes(struct work_struct *work)
  61 +{
  62 +       struct ocfs2_super *osb = container_of(work, struct ocfs2_super,
  63 +                                              dentry_lock_work);
  64 +
  65 +       __ocfs2_drop_dl_inodes(osb, DL_INODE_DROP_COUNT);
  66 +       /*
  67 +        * Don't queue dropping if umount is in progress. We flush the
  68 +        * list in ocfs2_dismount_volume
  69 +        */
  70 +       spin_lock(&dentry_list_lock);
  71 +       if (osb->dentry_lock_list &&
  72 +           !ocfs2_test_osb_flag(osb, OCFS2_OSB_DROP_DENTRY_LOCK_IMMED))
  73                 queue_work(ocfs2_wq, &osb->dentry_lock_work);
  74         spin_unlock(&dentry_list_lock);
  75  }
  76
  77 +/* Flush the whole work queue */
  78 +void ocfs2_drop_all_dl_inodes(struct ocfs2_super *osb)
  79 +{
  80 +       __ocfs2_drop_dl_inodes(osb, -1);
  81 +}
  82 +
  83  /*
  84   * ocfs2_dentry_iput() and friends.
  85   *
  86 @@ -353,7 +371,8 @@ static void ocfs2_drop_dentry_lock(struc
  87         /* We leave dropping of inode reference to ocfs2_wq as that can
  88          * possibly lead to inode deletion which gets tricky */
  89         spin_lock(&dentry_list_lock);
  90 -       if (!osb->dentry_lock_list)
  91 +       if (!osb->dentry_lock_list &&
  92 +           !ocfs2_test_osb_flag(osb, OCFS2_OSB_DROP_DENTRY_LOCK_IMMED))
  93                 queue_work(ocfs2_wq, &osb->dentry_lock_work);
  94         dl->dl_next = osb->dentry_lock_list;
  95         osb->dentry_lock_list = dl;
  96 diff -rupX /home/jack/.kerndiffexclude linux-2.6.27-SLE11_BRANCH/fs/ocfs2/dcache.h linux-2.6.27-SLE11_BRANCH-1-dentry_lock_drop//fs/ocfs2/dcache.h
  97 --- linux-2.6.27-SLE11_BRANCH/fs/ocfs2/dcache.h 2009-08-18 15:39:32.000000000 +0200
  98 +++ linux-2.6.27-SLE11_BRANCH-1-dentry_lock_drop//fs/ocfs2/dcache.h     2009-08-18 15:44:51.000000000 +0200
  99 @@ -49,10 +49,13 @@ struct ocfs2_dentry_lock {
 100  int ocfs2_dentry_attach_lock(struct dentry *dentry, struct inode *inode,
 101                              u64 parent_blkno);
 102
 103 +extern spinlock_t dentry_list_lock;
 104 +
 105  void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
 106                            struct ocfs2_dentry_lock *dl);
 107
 108  void ocfs2_drop_dl_inodes(struct work_struct *work);
 109 +void ocfs2_drop_all_dl_inodes(struct ocfs2_super *osb);
 110
 111  struct dentry *ocfs2_find_local_alias(struct inode *inode, u64 parent_blkno,
 112                                       int skip_unhashed);
 113 diff -rupX /home/jack/.kerndiffexclude linux-2.6.27-SLE11_BRANCH/fs/ocfs2/ocfs2.h linux-2.6.27-SLE11_BRANCH-1-dentry_lock_drop//fs/ocfs2/ocfs2.h
 114 --- linux-2.6.27-SLE11_BRANCH/fs/ocfs2/ocfs2.h  2009-08-18 15:39:32.000000000 +0200
 115 +++ linux-2.6.27-SLE11_BRANCH-1-dentry_lock_drop//fs/ocfs2/ocfs2.h      2009-08-18 15:44:51.000000000 +0200
 116 @@ -201,10 +201,12 @@ enum ocfs2_mount_options
 117         OCFS2_MOUNT_GRPQUOTA = 1 << 10, /* We support group quotas */
 118  };
 119
 120 -#define OCFS2_OSB_SOFT_RO      0x0001
 121 -#define OCFS2_OSB_HARD_RO      0x0002
 122 -#define OCFS2_OSB_ERROR_FS     0x0004
 123 -#define OCFS2_DEFAULT_ATIME_QUANTUM    60
 124 +#define OCFS2_OSB_SOFT_RO                      0x0001
 125 +#define OCFS2_OSB_HARD_RO                      0x0002
 126 +#define OCFS2_OSB_ERROR_FS                     0x0004
 127 +#define OCFS2_OSB_DROP_DENTRY_LOCK_IMMED       0x0008
 128 +
 129 +#define OCFS2_DEFAULT_ATIME_QUANTUM            60
 130
 131  struct ocfs2_journal;
 132  struct ocfs2_slot_info;
 133 @@ -400,6 +402,18 @@ static inline void ocfs2_set_osb_flag(st
 134         spin_unlock(&osb->osb_lock);
 135  }
 136
 137 +
 138 +static inline unsigned long  ocfs2_test_osb_flag(struct ocfs2_super *osb,
 139 +                                                unsigned long flag)
 140 +{
 141 +       unsigned long ret;
 142 +
 143 +       spin_lock(&osb->osb_lock);
 144 +       ret = osb->osb_flags & flag;
 145 +       spin_unlock(&osb->osb_lock);
 146 +       return ret;
 147 +}
 148 +
 149  static inline void ocfs2_set_ro_flag(struct ocfs2_super *osb,
 150                                      int hard)
 151  {
 152 diff -rupX /home/jack/.kerndiffexclude linux-2.6.27-SLE11_BRANCH/fs/ocfs2/super.c linux-2.6.27-SLE11_BRANCH-1-dentry_lock_drop//fs/ocfs2/super.c
 153 --- linux-2.6.27-SLE11_BRANCH/fs/ocfs2/super.c  2009-08-18 15:39:33.000000000 +0200
 154 +++ linux-2.6.27-SLE11_BRANCH-1-dentry_lock_drop//fs/ocfs2/super.c      2009-08-18 15:46:56.000000000 +0200
 155 @@ -1014,14 +1014,27 @@ static int ocfs2_get_sb(struct file_syst
 156                            mnt);
 157  }
 158
 159 +static void ocfs2_kill_sb(struct super_block *sb)
 160 +{
 161 +       struct ocfs2_super *osb = OCFS2_SB(sb);
 162 +
 163 +       /* Prevent further queueing of inode drop events */
 164 +       spin_lock(&dentry_list_lock);
 165 +       ocfs2_set_osb_flag(osb, OCFS2_OSB_DROP_DENTRY_LOCK_IMMED);
 166 +       spin_unlock(&dentry_list_lock);
 167 +       /* Wait for work to finish and/or remove it */
 168 +       cancel_work_sync(&osb->dentry_lock_work);
 169 +
 170 +       kill_block_super(sb);
 171 +}
 172 +
 173  static struct file_system_type ocfs2_fs_type = {
 174         .owner          = THIS_MODULE,
 175         .name           = "ocfs2",
 176         .get_sb         = ocfs2_get_sb, /* is this called when we mount
 177                                         * the fs? */
 178 -       .kill_sb        = kill_block_super, /* set to the generic one
 179 -                                            * right now, but do we
 180 -                                            * need to change that? */
 181 +       .kill_sb        = ocfs2_kill_sb,
 182 +
 183         .fs_flags       = FS_REQUIRES_DEV|FS_RENAME_DOES_D_MOVE,
 184         .next           = NULL
 185  };
 186 @@ -1621,6 +1634,12 @@ static void ocfs2_dismount_volume(struct
 187         osb = OCFS2_SB(sb);
 188         BUG_ON(!osb);
 189
 190 +       /*
 191 +        * Flush inode dropping work queue so that deletes are
 192 +        * performed while the filesystem is still working
 193 +        */
 194 +       ocfs2_drop_all_dl_inodes(osb);
 195 +
 196         ocfs2_disable_quotas(osb);
 197
 198         ocfs2_shutdown_local_alloc(osb);