ext4: Add inode version support in ext4

This patch adds 64-bit inode version support to ext4. The lower 32 bits
are stored in the osd1.linux1.l_i_version field while the high 32 bits
are stored in the i_version_hi field newly created in the ext4_inode.
This field is incremented in case the ext4_inode is large enough. A
i_version mount option has been added to enable the feature.

Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Andreas Dilger <adilger@clusterfs.com>
Signed-off-by: Kalpak Shah <kalpak@clusterfs.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Jean Noel Cordenner <jean-noel.cordenner@bull.net>

5 files changed, 45 insertions, 22 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 89cd35386ff5..a06a3b7cfc34 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2781,6 +2781,13 @@ void ext4_read_inode(struct inode * inode)
         EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
         EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
 
+        inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
+        if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
+                if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
+                        inode->i_version |=
+                        (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
+        }
+
         if (S_ISREG(inode->i_mode)) {
                 inode->i_op = &ext4_file_inode_operations;
                 inode->i_fop = &ext4_file_operations;
@@ -2963,8 +2970,14 @@ static int ext4_do_update_inode(handle_t *handle,
         } else for (block = 0; block < EXT4_N_BLOCKS; block++)
                 raw_inode->i_block[block] = ei->i_data[block];
 
-        if (ei->i_extra_isize)
+        raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
+        if (ei->i_extra_isize) {
+                if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
+                        raw_inode->i_version_hi =
+                        cpu_to_le32(inode->i_version >> 32);
                 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
+        }
+
 
         BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
         rc = ext4_journal_dirty_metadata(handle, bh);
@@ -3191,6 +3204,9 @@ int ext4_mark_iloc_dirty(handle_t *handle,
 {
         int err = 0;
 
+        if (test_opt(inode->i_sb, I_VERSION))
+                inode_inc_iversion(inode);
+
         /* the do_update_inode consumes one bh->b_count */
         get_bh(iloc->bh);
 
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index f7479d30735e..aa22acd6eb06 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -732,6 +732,8 @@ static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
                 seq_puts(seq, ",nobh");
         if (!test_opt(sb, EXTENTS))
                 seq_puts(seq, ",noextents");
+        if (test_opt(sb, I_VERSION))
+                seq_puts(seq, ",i_version");
 
         if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
                 seq_puts(seq, ",data=journal");
@@ -874,7 +876,7 @@ enum {
         Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
         Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_quota, Opt_noquota,
         Opt_ignore, Opt_barrier, Opt_err, Opt_resize, Opt_usrquota,
-        Opt_grpquota, Opt_extents, Opt_noextents,
+        Opt_grpquota, Opt_extents, Opt_noextents, Opt_i_version,
 };
 
 static match_table_t tokens = {
@@ -928,6 +930,7 @@ static match_table_t tokens = {
         {Opt_barrier, "barrier=%u"},
         {Opt_extents, "extents"},
         {Opt_noextents, "noextents"},
+        {Opt_i_version, "i_version"},
         {Opt_err, NULL},
         {Opt_resize, "resize"},
 };
@@ -1273,6 +1276,10 @@ clear_qf_name:
                 case Opt_noextents:
                         clear_opt (sbi->s_mount_opt, EXTENTS);
                         break;
+                case Opt_i_version:
+                        set_opt(sbi->s_mount_opt, I_VERSION);
+                        sb->s_flags |= MS_I_VERSION;
+                        break;
                 default:
                         printk (KERN_ERR
                                 "EXT4-fs: Unrecognized mount option \"%s\" "
@@ -3197,7 +3204,6 @@ out:
                 i_size_write(inode, off+len-towrite);
                 EXT4_I(inode)->i_disksize = inode->i_size;
         }
-        inode->i_version++;
         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
         ext4_mark_inode_dirty(handle, inode);
         mutex_unlock(&inode->i_mutex);
diff --git a/fs/inode.c b/fs/inode.c
index b48324a94c2b..276ffd6b6fdd 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1243,23 +1243,6 @@ void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
 EXPORT_SYMBOL(touch_atime);
 
 /**
- *     inode_inc_iversion      -       increments i_version
- *     @inode: inode that need to be updated
- *
- *     Every time the inode is modified, the i_version field
- *     will be incremented.
- *     The filesystem has to be mounted with i_version flag
- *
- */
-
-void inode_inc_iversion(struct inode *inode)
-{
-        spin_lock(&inode->i_lock);
-        inode->i_version++;
-        spin_unlock(&inode->i_lock);
-}
-
-/**
  *      file_update_time        -       update mtime and ctime time
  *      @file: file accessed
  *
diff --git a/include/linux/ext4_fs.h b/include/linux/ext4_fs.h
index cd406dba0e64..b6092940c8b8 100644
--- a/include/linux/ext4_fs.h
+++ b/include/linux/ext4_fs.h
@@ -292,7 +292,7 @@ struct ext4_inode {
         __le32  i_flags;        /* File flags */
         union {
                 struct {
-                        __u32  l_i_reserved1;
+                        __le32  l_i_version;
                 } linux1;
                 struct {
                         __u32  h_i_translator;
@@ -334,6 +334,7 @@ struct ext4_inode {
         __le32  i_atime_extra;  /* extra Access time      (nsec << 2 | epoch) */
         __le32  i_crtime;       /* File Creation time */
         __le32  i_crtime_extra; /* extra FileCreationtime (nsec << 2 | epoch) */
+        __le32  i_version_hi;   /* high 32 bits for 64-bit version */
 };
 
 
@@ -407,6 +408,8 @@ do {									       \
                                        raw_inode->xtime ## _extra);            \
 } while (0)
 
+#define i_disk_version osd1.linux1.l_i_version
+
 #if defined(__KERNEL__) || defined(__linux__)
 #define i_reserved1     osd1.linux1.l_i_reserved1
 #define i_file_acl_high osd2.linux2.l_i_file_acl_high
@@ -469,6 +472,7 @@ do {									       \
 #define EXT4_MOUNT_EXTENTS              0x400000 /* Extents support */
 #define EXT4_MOUNT_JOURNAL_CHECKSUM     0x800000 /* Journal checksums */
 #define EXT4_MOUNT_JOURNAL_ASYNC_COMMIT 0x1000000 /* Journal Async Commit */
+#define EXT4_MOUNT_I_VERSION            0x2000000 /* i_version support */
 /* Compatibility, for having both ext2_fs.h and ext4_fs.h included at once */
 #ifndef _LINUX_EXT2_FS_H
 #define clear_opt(o, opt)               o &= ~EXT4_MOUNT_##opt
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9608839552b3..a516b6716870 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1396,7 +1396,21 @@ static inline void inode_dec_link_count(struct inode *inode)
         mark_inode_dirty(inode);
 }
 
-extern void inode_inc_iversion(struct inode *inode);
+/**
+ * inode_inc_iversion - increments i_version
+ * @inode: inode that need to be updated
+ *
+ * Every time the inode is modified, the i_version field will be incremented.
+ * The filesystem has to be mounted with i_version flag
+ */
+
+static inline void inode_inc_iversion(struct inode *inode)
+{
+       spin_lock(&inode->i_lock);
+       inode->i_version++;
+       spin_unlock(&inode->i_lock);
+}
+
 extern void touch_atime(struct vfsmount *mnt, struct dentry *dentry);
 static inline void file_accessed(struct file *file)
 {