include/uapi/linux/ext4.h
Source file repositories/reference/linux-study-clean/include/uapi/linux/ext4.h
File Facts
- System
- Linux kernel
- Corpus path
include/uapi/linux/ext4.h- Extension
.h- Size
- 5842 bytes
- Lines
- 171
- Domain
- Core OS
- Bucket
- Core Kernel Interface
- Inferred role
- Core OS: implementation source
- Status
- source implementation candidate
Why This File Exists
Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.
- Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.
- Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.
Dependency Surface
linux/fiemap.hlinux/fs.hlinux/ioctl.hlinux/types.h
Detected Declarations
struct fsuuidstruct move_extentstruct ext4_new_group_inputstruct ext4_tune_sb_params
Annotated Snippet
struct fsuuid {
__u32 fsu_len;
__u32 fsu_flags;
__u8 fsu_uuid[];
};
/*
* Structure for EXT4_IOC_MOVE_EXT
*/
struct move_extent {
__u32 reserved; /* should be zero */
__u32 donor_fd; /* donor file descriptor */
__u64 orig_start; /* logical start offset in block for orig */
__u64 donor_start; /* logical start offset in block for donor */
__u64 len; /* block length to be moved */
__u64 moved_len; /* moved block length */
};
/*
* Flags used by EXT4_IOC_SHUTDOWN
*/
#define EXT4_GOING_FLAGS_DEFAULT 0x0 /* going down */
#define EXT4_GOING_FLAGS_LOGFLUSH 0x1 /* flush log but not data */
#define EXT4_GOING_FLAGS_NOLOGFLUSH 0x2 /* don't flush log nor data */
/* Used to pass group descriptor data when online resize is done */
struct ext4_new_group_input {
__u32 group; /* Group number for this data */
__u64 block_bitmap; /* Absolute block number of block bitmap */
__u64 inode_bitmap; /* Absolute block number of inode bitmap */
__u64 inode_table; /* Absolute block number of inode table start */
__u32 blocks_count; /* Total number of blocks in this group */
__u16 reserved_blocks; /* Number of reserved blocks in this group */
__u16 unused;
};
struct ext4_tune_sb_params {
__u32 set_flags;
__u32 checkinterval;
__u16 errors_behavior;
__u16 mnt_count;
__u16 max_mnt_count;
__u16 raid_stride;
__u64 last_check_time;
__u64 reserved_blocks;
__u64 blocks_count;
__u32 default_mnt_opts;
__u32 reserved_uid;
__u32 reserved_gid;
__u32 raid_stripe_width;
__u16 encoding;
__u16 encoding_flags;
__u8 def_hash_alg;
__u8 pad_1;
__u16 pad_2;
__u32 feature_compat;
__u32 feature_incompat;
__u32 feature_ro_compat;
__u32 set_feature_compat_mask;
__u32 set_feature_incompat_mask;
__u32 set_feature_ro_compat_mask;
__u32 clear_feature_compat_mask;
__u32 clear_feature_incompat_mask;
__u32 clear_feature_ro_compat_mask;
__u8 mount_opts[64];
__u8 pad[68];
};
#define EXT4_TUNE_FL_ERRORS_BEHAVIOR 0x00000001
#define EXT4_TUNE_FL_MNT_COUNT 0x00000002
#define EXT4_TUNE_FL_MAX_MNT_COUNT 0x00000004
#define EXT4_TUNE_FL_CHECKINTRVAL 0x00000008
#define EXT4_TUNE_FL_LAST_CHECK_TIME 0x00000010
#define EXT4_TUNE_FL_RESERVED_BLOCKS 0x00000020
#define EXT4_TUNE_FL_RESERVED_UID 0x00000040
#define EXT4_TUNE_FL_RESERVED_GID 0x00000080
#define EXT4_TUNE_FL_DEFAULT_MNT_OPTS 0x00000100
#define EXT4_TUNE_FL_DEF_HASH_ALG 0x00000200
#define EXT4_TUNE_FL_RAID_STRIDE 0x00000400
#define EXT4_TUNE_FL_RAID_STRIPE_WIDTH 0x00000800
#define EXT4_TUNE_FL_MOUNT_OPTS 0x00001000
#define EXT4_TUNE_FL_FEATURES 0x00002000
#define EXT4_TUNE_FL_EDIT_FEATURES 0x00004000
#define EXT4_TUNE_FL_FORCE_FSCK 0x00008000
#define EXT4_TUNE_FL_ENCODING 0x00010000
#define EXT4_TUNE_FL_ENCODING_FLAGS 0x00020000
/*
* 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.
Annotation
- Immediate include surface: `linux/fiemap.h`, `linux/fs.h`, `linux/ioctl.h`, `linux/types.h`.
- Detected declarations: `struct fsuuid`, `struct move_extent`, `struct ext4_new_group_input`, `struct ext4_tune_sb_params`.
- Atlas domain: Core OS / Core Kernel Interface.
- Implementation status: source implementation candidate.
Implementation Notes
- This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
- Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
- Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.