[PATCH 03/11] fs: add support for an inode to carry stream related data

[Jens Axboe]

No functional changes in this patch, just in preparation for
allowing applications to pass in hints about data life times
for writes.

Pack the i_stream field into a 2-byte hole, so we don't grow
the size of the inode.

Reviewed-by: Andreas Dilger <adil...@dilger.ca>
Signed-off-by: Jens Axboe <ax...@kernel.dk>
---
 fs/inode.c         | 1 +
 include/linux/fs.h | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/fs/inode.c b/fs/inode.c
index db5914783a71..5717cb378fda 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -149,6 +149,7 @@ int inode_init_always(struct super_block *sb, struct inode 
*inode)
        inode->i_blocks = 0;
        inode->i_bytes = 0;
        inode->i_generation = 0;
+       inode->i_stream = 0;
        inode->i_pipe = NULL;
        inode->i_bdev = NULL;
        inode->i_cdev = NULL;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 803e5a9b2654..771e172d23d7 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -591,6 +591,7 @@ struct inode {
        struct timespec         i_ctime;
        spinlock_t              i_lock; /* i_blocks, i_bytes, maybe i_size */
        unsigned short          i_bytes;
+       unsigned short          i_stream;
        unsigned int            i_blkbits;
        blkcnt_t                i_blocks;
 
@@ -655,6 +656,14 @@ struct inode {
        void                    *i_private; /* fs or device private pointer */
 };
 
+static inline unsigned int inode_streamid(struct inode *inode)
+{
+       if (inode)
+               return inode->i_stream;
+
+       return 0;
+}
+
 static inline unsigned int i_blocksize(const struct inode *node)
 {
        return (1 << node->i_blkbits);
-- 
2.7.4