@@ -191,6 +191,7 @@ struct btrfs_inode {
/* flags field from the on disk inode */
u32 flags;
+ u64 compat_flags;
/*
* Counters to keep track of the number of extent item's we may use due
@@ -1752,6 +1752,7 @@ BTRFS_SETGET_FUNCS(inode_gid, struct btrfs_inode_item, gid, 32);
BTRFS_SETGET_FUNCS(inode_mode, struct btrfs_inode_item, mode, 32);
BTRFS_SETGET_FUNCS(inode_rdev, struct btrfs_inode_item, rdev, 64);
BTRFS_SETGET_FUNCS(inode_flags, struct btrfs_inode_item, flags, 64);
+BTRFS_SETGET_FUNCS(inode_compat_flags, struct btrfs_inode_item, compat_flags, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_generation, struct btrfs_inode_item,
generation, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_sequence, struct btrfs_inode_item,
@@ -1769,6 +1770,7 @@ BTRFS_SETGET_STACK_FUNCS(stack_inode_gid, struct btrfs_inode_item, gid, 32);
BTRFS_SETGET_STACK_FUNCS(stack_inode_mode, struct btrfs_inode_item, mode, 32);
BTRFS_SETGET_STACK_FUNCS(stack_inode_rdev, struct btrfs_inode_item, rdev, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_flags, struct btrfs_inode_item, flags, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_inode_compat_flags, struct btrfs_inode_item, compat_flags, 64);
BTRFS_SETGET_FUNCS(timespec_sec, struct btrfs_timespec, sec, 64);
BTRFS_SETGET_FUNCS(timespec_nsec, struct btrfs_timespec, nsec, 32);
BTRFS_SETGET_STACK_FUNCS(stack_timespec_sec, struct btrfs_timespec, sec, 64);
@@ -1733,6 +1733,7 @@ static void fill_stack_inode_item(struct btrfs_trans_handle *trans,
btrfs_set_stack_inode_transid(inode_item, trans->transid);
btrfs_set_stack_inode_rdev(inode_item, inode->i_rdev);
btrfs_set_stack_inode_flags(inode_item, BTRFS_I(inode)->flags);
+ btrfs_set_stack_inode_compat_flags(inode_item, BTRFS_I(inode)->compat_flags);
btrfs_set_stack_inode_block_group(inode_item, 0);
btrfs_set_stack_timespec_sec(&inode_item->atime,
@@ -1791,6 +1792,7 @@ int btrfs_fill_inode(struct inode *inode, u32 *rdev)
inode->i_rdev = 0;
*rdev = btrfs_stack_inode_rdev(inode_item);
BTRFS_I(inode)->flags = btrfs_stack_inode_flags(inode_item);
+ BTRFS_I(inode)->compat_flags = btrfs_stack_inode_compat_flags(inode_item);
inode->i_atime.tv_sec = btrfs_stack_timespec_sec(&inode_item->atime);
inode->i_atime.tv_nsec = btrfs_stack_timespec_nsec(&inode_item->atime);
@@ -3481,6 +3481,7 @@ static int btrfs_read_locked_inode(struct inode *inode,
BTRFS_I(inode)->index_cnt = (u64)-1;
BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
+ BTRFS_I(inode)->compat_flags = btrfs_inode_compat_flags(leaf, inode_item);
cache_index:
/*
@@ -3647,6 +3648,7 @@ static void fill_inode_item(struct btrfs_trans_handle *trans,
btrfs_set_token_inode_transid(&token, item, trans->transid);
btrfs_set_token_inode_rdev(&token, item, inode->i_rdev);
btrfs_set_token_inode_flags(&token, item, BTRFS_I(inode)->flags);
+ btrfs_set_token_inode_compat_flags(&token, item, BTRFS_I(inode)->compat_flags);
btrfs_set_token_inode_block_group(&token, item, 0);
}
@@ -8663,6 +8665,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
ei->defrag_bytes = 0;
ei->disk_i_size = 0;
ei->flags = 0;
+ ei->compat_flags = 0;
ei->csum_bytes = 0;
ei->index_cnt = (u64)-1;
ei->dir_index = 0;
@@ -102,8 +102,9 @@ static unsigned int btrfs_mask_fsflags_for_type(struct inode *inode,
* Export internal inode flags to the format expected by the FS_IOC_GETFLAGS
* ioctl.
*/
-static unsigned int btrfs_inode_flags_to_fsflags(unsigned int flags)
+static unsigned int btrfs_inode_flags_to_fsflags(struct btrfs_inode *binode)
{
+ unsigned int flags = binode->flags;
unsigned int iflags = 0;
if (flags & BTRFS_INODE_SYNC)
@@ -156,7 +157,7 @@ void btrfs_sync_inode_flags_to_i_flags(struct inode *inode)
static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
{
struct btrfs_inode *binode = BTRFS_I(file_inode(file));
- unsigned int flags = btrfs_inode_flags_to_fsflags(binode->flags);
+ unsigned int flags = btrfs_inode_flags_to_fsflags(binode);
if (copy_to_user(arg, &flags, sizeof(flags)))
return -EFAULT;
@@ -228,7 +229,7 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
inode_lock(inode);
fsflags = btrfs_mask_fsflags_for_type(inode, fsflags);
- old_fsflags = btrfs_inode_flags_to_fsflags(binode->flags);
+ old_fsflags = btrfs_inode_flags_to_fsflags(binode);
ret = vfs_ioc_setflags_prepare(inode, old_fsflags, fsflags);
if (ret)
@@ -3895,6 +3895,7 @@ static void fill_inode_item(struct btrfs_trans_handle *trans,
btrfs_set_token_inode_transid(&token, item, trans->transid);
btrfs_set_token_inode_rdev(&token, item, inode->i_rdev);
btrfs_set_token_inode_flags(&token, item, BTRFS_I(inode)->flags);
+ btrfs_set_token_inode_compat_flags(&token, item, BTRFS_I(inode)->compat_flags);
btrfs_set_token_inode_block_group(&token, item, 0);
}
@@ -574,11 +574,16 @@ struct btrfs_inode_item {
/* modification sequence number for NFS */
__le64 sequence;
+ /*
+ * flags which aren't checked for corruption at mount
+ * and can be added in a backwards compatible way
+ */
+ __le64 compat_flags;
/*
* a little future expansion, for more than this we can
* just grow the inode item and version it
*/
- __le64 reserved[4];
+ __le64 reserved[3];
struct btrfs_timespec atime;
struct btrfs_timespec ctime;
struct btrfs_timespec mtime;
The tree checker currently rejects unrecognized flags when it reads btrfs_inode_item. Practically, this means that adding a new flag makes the change backwards incompatible if the flag is ever set on a file. Take up one of the 4 reserved u64 fields in the btrfs_inode_item as a new "compat_flags". These flags are zero on inode creation in btrfs and mkfs and are ignored by an older kernel, so it should be safe to use them in this way. Signed-off-by: Boris Burkov <boris@bur.io> --- fs/btrfs/btrfs_inode.h | 1 + fs/btrfs/ctree.h | 2 ++ fs/btrfs/delayed-inode.c | 2 ++ fs/btrfs/inode.c | 3 +++ fs/btrfs/ioctl.c | 7 ++++--- fs/btrfs/tree-log.c | 1 + include/uapi/linux/btrfs_tree.h | 7 ++++++- 7 files changed, 19 insertions(+), 4 deletions(-)