ext4: add new ioctl EXT4_IOC_GET_ES_CACHE
For debugging reasons, it's useful to know the contents of the extent
cache. Since the extent cache contains much of what is in the fiemap
ioctl, use an fiemap-style interface to return this information.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index ee29679..e2d8ad2 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -652,6 +652,7 @@ enum {
/* ioctl codes 19--39 are reserved for fscrypt */
#define EXT4_IOC_CLEAR_ES_CACHE _IO('f', 40)
#define EXT4_IOC_GETSTATE _IOW('f', 41, __u32)
+#define EXT4_IOC_GET_ES_CACHE _IOWR('f', 42, struct fiemap)
#define EXT4_IOC_FSGETXATTR FS_IOC_FSGETXATTR
#define EXT4_IOC_FSSETXATTR FS_IOC_FSSETXATTR
@@ -692,6 +693,12 @@ enum {
#define EXT4_IOC32_SETVERSION_OLD FS_IOC32_SETVERSION
#endif
+/*
+ * Returned by EXT4_IOC_GET_ES_CACHE as an additional possible flag.
+ * It indicates that the entry in extent status cache is for a hole.
+ */
+#define EXT4_FIEMAP_EXTENT_HOLE 0x08000000
+
/* Max physical block we can address w/o extents */
#define EXT4_MAX_BLOCK_FILE_PHYS 0xFFFFFFFF
@@ -3258,6 +3265,9 @@ extern int ext4_ext_check_inode(struct inode *inode);
extern ext4_lblk_t ext4_ext_next_allocated_block(struct ext4_ext_path *path);
extern int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
__u64 start, __u64 len);
+extern int ext4_get_es_cache(struct inode *inode,
+ struct fiemap_extent_info *fieinfo,
+ __u64 start, __u64 len);
extern int ext4_ext_precache(struct inode *inode);
extern int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len);
extern int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len);