[PATCH 08/18] fs: add inode reference coutn read accessor

From: Dave Chinner
Date: Fri Oct 08 2010 - 01:24:04 EST

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From: Dave Chinner <dchinner@xxxxxxxxxx>

To remove most of the remaining direct references to the inode
reference count, add an iref_read() accessor function to read the
current reference count. New users of this function should be
frowned upon, as there is rarely a good reason for looking at the
current reference count.

Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
arch/powerpc/platforms/cell/spufs/file.c | 2 +-
drivers/staging/pohmelfs/inode.c | 10 +++++-----
fs/btrfs/inode.c | 6 +++---
fs/ceph/mds_client.c | 2 +-
fs/cifs/inode.c | 2 +-
fs/ext3/ialloc.c | 4 ++--
fs/ext4/ialloc.c | 4 ++--
fs/fs-writeback.c | 2 +-
fs/hpfs/inode.c | 2 +-
fs/inode.c | 10 ++++++++++
fs/locks.c | 2 +-
fs/logfs/readwrite.c | 2 +-
fs/nfs/inode.c | 4 ++--
fs/notify/inode_mark.c | 11 +++++------
fs/reiserfs/stree.c | 2 +-
fs/smbfs/inode.c | 2 +-
fs/ubifs/super.c | 2 +-
fs/xfs/linux-2.6/xfs_trace.h | 2 +-
fs/xfs/xfs_inode.h | 2 +-
include/linux/fs.h | 1 +
20 files changed, 42 insertions(+), 32 deletions(-)

diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index 1a40da9..2e4263c 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -1549,7 +1549,7 @@ static int spufs_mfc_open(struct inode *inode, struct file *file)
if (ctx->owner != current->mm)
return -EINVAL;

- if (atomic_read(&inode->i_count) != 1)
+ if (iref_read(inode) != 1)
return -EBUSY;

mutex_lock(&ctx->mapping_lock);
diff --git a/drivers/staging/pohmelfs/inode.c b/drivers/staging/pohmelfs/inode.c
index 97dae29..d8a308d 100644
--- a/drivers/staging/pohmelfs/inode.c
+++ b/drivers/staging/pohmelfs/inode.c
@@ -1289,11 +1289,11 @@ static void pohmelfs_put_super(struct super_block *sb)
dprintk("%s: ino: %llu, pi: %p, inode: %p, count: %u.\n",
__func__, pi->ino, pi, inode, count);

- if (atomic_read(&inode->i_count) != count) {
+ if (iref_read(inode) != count) {
printk("%s: ino: %llu, pi: %p, inode: %p, count: %u, i_count: %d.\n",
__func__, pi->ino, pi, inode, count,
- atomic_read(&inode->i_count));
- count = atomic_read(&inode->i_count);
+ iref_read(inode));
+ count = iref_read(inode);
in_drop_list++;
}

@@ -1305,7 +1305,7 @@ static void pohmelfs_put_super(struct super_block *sb)
pi = POHMELFS_I(inode);

dprintk("%s: ino: %llu, pi: %p, inode: %p, i_count: %u.\n",
- __func__, pi->ino, pi, inode, atomic_read(&inode->i_count));
+ __func__, pi->ino, pi, inode, iref_read(inode));

/*
* These are special inodes, they were created during
@@ -1313,7 +1313,7 @@ static void pohmelfs_put_super(struct super_block *sb)
* so they live here with reference counter being 1 and prevent
* umount from succeed since it believes that they are busy.
*/
- count = atomic_read(&inode->i_count);
+ count = iref_read(inode);
if (count) {
list_del_init(&inode->i_sb_list);
while (count--)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 0c3a35b..2953e9f 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2718,10 +2718,10 @@ static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
return ERR_PTR(-ENOSPC);

/* check if there is someone else holds reference */
- if (S_ISDIR(inode->i_mode) && atomic_read(&inode->i_count) > 1)
+ if (S_ISDIR(inode->i_mode) && iref_read(inode) > 1)
return ERR_PTR(-ENOSPC);

- if (atomic_read(&inode->i_count) > 2)
+ if (iref_read(inode) > 2)
return ERR_PTR(-ENOSPC);

if (xchg(&root->fs_info->enospc_unlink, 1))
@@ -3939,7 +3939,7 @@ again:
inode = igrab(&entry->vfs_inode);
if (inode) {
spin_unlock(&root->inode_lock);
- if (atomic_read(&inode->i_count) > 1)
+ if (iref_read(inode) > 1)
d_prune_aliases(inode);
/*
* btrfs_drop_inode will have it removed from
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index fad95f8..b6d0ef1 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1102,7 +1102,7 @@ static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
spin_unlock(&inode->i_lock);
d_prune_aliases(inode);
dout("trim_caps_cb %p cap %p pruned, count now %d\n",
- inode, cap, atomic_read(&inode->i_count));
+ inode, cap, iref_read(inode));
return 0;
}

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 63a0bdb..74cb762 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1641,7 +1641,7 @@ int cifs_revalidate_dentry(struct dentry *dentry)
}

cFYI(1, "Revalidate: %s inode 0x%p count %d dentry: 0x%p d_time %ld "
- "jiffies %ld", full_path, inode, inode->i_count.counter,
+ "jiffies %ld", full_path, inode, iref_read(inode),
dentry, dentry->d_time, jiffies);

if (CIFS_SB(sb)->tcon->unix_ext)
diff --git a/fs/ext3/ialloc.c b/fs/ext3/ialloc.c
index 4ab72db..64669aa 100644
--- a/fs/ext3/ialloc.c
+++ b/fs/ext3/ialloc.c
@@ -100,9 +100,9 @@ void ext3_free_inode (handle_t *handle, struct inode * inode)
struct ext3_sb_info *sbi;
int fatal = 0, err;

- if (atomic_read(&inode->i_count) > 1) {
+ if (iref_read(inode) > 1) {
printk ("ext3_free_inode: inode has count=%d\n",
- atomic_read(&inode->i_count));
+ iref_read(inode));
return;
}
if (inode->i_nlink) {
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 45853e0..38ac6e5 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -189,9 +189,9 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
struct ext4_sb_info *sbi;
int fatal = 0, err, count, cleared;

- if (atomic_read(&inode->i_count) > 1) {
+ if (iref_read(inode) > 1) {
printk(KERN_ERR "ext4_free_inode: inode has count=%d\n",
- atomic_read(&inode->i_count));
+ iref_read(inode));
return;
}
if (inode->i_nlink) {
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 1bf8a28..ec7a689 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -315,7 +315,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
unsigned dirty;
int ret;

- if (!atomic_read(&inode->i_count))
+ if (!iref_read(inode))
WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING)));
else
WARN_ON(inode->i_state & I_WILL_FREE);
diff --git a/fs/hpfs/inode.c b/fs/hpfs/inode.c
index 56f0da1..05b5d79 100644
--- a/fs/hpfs/inode.c
+++ b/fs/hpfs/inode.c
@@ -183,7 +183,7 @@ void hpfs_write_inode(struct inode *i)
struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
struct inode *parent;
if (i->i_ino == hpfs_sb(i->i_sb)->sb_root) return;
- if (hpfs_inode->i_rddir_off && !atomic_read(&i->i_count)) {
+ if (hpfs_inode->i_rddir_off && !iref_read(i)) {
if (*hpfs_inode->i_rddir_off) printk("HPFS: write_inode: some position still there\n");
kfree(hpfs_inode->i_rddir_off);
hpfs_inode->i_rddir_off = NULL;
diff --git a/fs/inode.c b/fs/inode.c
index aa66e07..b1dc6dc 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -331,6 +331,16 @@ void iref_locked(struct inode *inode)
atomic_inc(&inode->i_count);
}

+/*
+ * Nobody outside of core code should really be looking at the inode reference
+ * count. Please don't add new users of this function.
+ */
+int iref_read(struct inode *inode)
+{
+ return atomic_read(&inode->i_count);
+}
+EXPORT_SYMBOL_GPL(iref_read);
+
void end_writeback(struct inode *inode)
{
might_sleep();
diff --git a/fs/locks.c b/fs/locks.c
index ab24d49..cbf3114 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1376,7 +1376,7 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
goto out;
if ((arg == F_WRLCK)
&& ((atomic_read(&dentry->d_count) > 1)
- || (atomic_read(&inode->i_count) > 1)))
+ || (iref_read(inode) > 1)))
goto out;
}

diff --git a/fs/logfs/readwrite.c b/fs/logfs/readwrite.c
index 6127baf..8beb842 100644
--- a/fs/logfs/readwrite.c
+++ b/fs/logfs/readwrite.c
@@ -1002,7 +1002,7 @@ static int __logfs_is_valid_block(struct inode *inode, u64 bix, u64 ofs)
{
struct logfs_inode *li = logfs_inode(inode);

- if ((inode->i_nlink == 0) && atomic_read(&inode->i_count) == 1)
+ if ((inode->i_nlink == 0) && iref_read(inode) == 1)
return 0;

if (bix < I0_BLOCKS)
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 886be68..387f4dc 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -385,7 +385,7 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr)
dprintk("NFS: nfs_fhget(%s/%Ld ct=%d)\n",
inode->i_sb->s_id,
(long long)NFS_FILEID(inode),
- atomic_read(&inode->i_count));
+ iref_read(inode));

out:
return inode;
@@ -1191,7 +1191,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)

dfprintk(VFS, "NFS: %s(%s/%ld ct=%d info=0x%x)\n",
__func__, inode->i_sb->s_id, inode->i_ino,
- atomic_read(&inode->i_count), fattr->valid);
+ iref_read(inode), fattr->valid);

if ((fattr->valid & NFS_ATTR_FATTR_FILEID) && nfsi->fileid != fattr->fileid)
goto out_fileid;
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 8096a9e..6c54e02 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -252,12 +252,12 @@ void fsnotify_unmount_inodes(struct list_head *list)
continue;

/*
- * If i_count is zero, the inode cannot have any watches and
- * doing an iref/iput with MS_ACTIVE clear would actually
- * evict all inodes with zero i_count from icache which is
+ * If the inode is not referenced, the inode cannot have any
+ * watches and doing an iref/iput with MS_ACTIVE clear would
+ * actually evict all unreferenced inodes from icache which is
* unnecessarily violent and may in fact be illegal to do.
*/
- if (!atomic_read(&inode->i_count))
+ if (!iref_read(inode))
continue;

need_iput_tmp = need_iput;
@@ -270,8 +270,7 @@ void fsnotify_unmount_inodes(struct list_head *list)
need_iput_tmp = NULL;

/* In case the dropping of a reference would nuke next_i. */
- if ((&next_i->i_sb_list != list) &&
- atomic_read(&next_i->i_count) &&
+ if ((&next_i->i_sb_list != list) && iref_read(inode) &&
!(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
iref_locked(next_i);
need_iput = next_i;
diff --git a/fs/reiserfs/stree.c b/fs/reiserfs/stree.c
index 313d39d..55c3ad3 100644
--- a/fs/reiserfs/stree.c
+++ b/fs/reiserfs/stree.c
@@ -1477,7 +1477,7 @@ static int maybe_indirect_to_direct(struct reiserfs_transaction_handle *th,
** reading in the last block. The user will hit problems trying to
** read the file, but for now we just skip the indirect2direct
*/
- if (atomic_read(&inode->i_count) > 1 ||
+ if (iref_read(inode) > 1 ||
!tail_has_to_be_packed(inode) ||
!page || (REISERFS_I(inode)->i_flags & i_nopack_mask)) {
/* leave tail in an unformatted node */
diff --git a/fs/smbfs/inode.c b/fs/smbfs/inode.c
index 450c919..792593b 100644
--- a/fs/smbfs/inode.c
+++ b/fs/smbfs/inode.c
@@ -320,7 +320,7 @@ out:
}

/*
- * This routine is called when i_nlink == 0 and i_count goes to 0.
+ * This routine is called when i_nlink == 0 and the reference count goes to 0.
* All blocking cleanup operations need to go here to avoid races.
*/
static void
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 45888fb..a1b109c 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -342,7 +342,7 @@ static void ubifs_evict_inode(struct inode *inode)
goto out;

dbg_gen("inode %lu, mode %#x", inode->i_ino, (int)inode->i_mode);
- ubifs_assert(!atomic_read(&inode->i_count));
+ ubifs_assert(!iref_read(inode));

truncate_inode_pages(&inode->i_data, 0);

diff --git a/fs/xfs/linux-2.6/xfs_trace.h b/fs/xfs/linux-2.6/xfs_trace.h
index be5dffd..c3940ab 100644
--- a/fs/xfs/linux-2.6/xfs_trace.h
+++ b/fs/xfs/linux-2.6/xfs_trace.h
@@ -599,7 +599,7 @@ DECLARE_EVENT_CLASS(xfs_iref_class,
TP_fast_assign(
__entry->dev = VFS_I(ip)->i_sb->s_dev;
__entry->ino = ip->i_ino;
- __entry->count = atomic_read(&VFS_I(ip)->i_count);
+ __entry->count = iref_read(VFS_I(ip));
__entry->pincount = atomic_read(&ip->i_pincount);
__entry->caller_ip = caller_ip;
),
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index cbb4791..5000660 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -481,7 +481,7 @@ void xfs_mark_inode_dirty_sync(xfs_inode_t *);

#define IHOLD(ip) \
do { \
- ASSERT(atomic_read(&VFS_I(ip)->i_count) > 0) ; \
+ ASSERT(iref_read(VFS_I(ip)) > 0) ; \
iref(VFS_I(ip)); \
trace_xfs_ihold(ip, _THIS_IP_); \
} while (0)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 2e971f2..6f0df2a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2186,6 +2186,7 @@ extern void unlock_new_inode(struct inode *);

extern void iref(struct inode *inode);
extern void iref_locked(struct inode *inode);
+extern int iref_read(struct inode *inode);
extern void iget_failed(struct inode *);
extern void end_writeback(struct inode *);
extern void destroy_inode(struct inode *);
--
1.7.1

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Next message: Dave Chinner: "[PATCH 13/18] fs: split locking of inode writeback and LRU lists"
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