fs/ext4/ext4.h

Source file repositories/reference/linux-study-clean/fs/ext4/ext4.h

File Facts

System: Linux kernel
Corpus path: fs/ext4/ext4.h
Extension: .h
Size: 142912 bytes
Lines: 4042
Domain: Core OS
Bucket: VFS And Filesystem Core
Inferred role: Core OS: operation-table or driver-model contract
Status: pattern 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 an operation table; this is where Linux turns generic core objects into subsystem-specific behavior.
Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
Allocates kernel memory; connect allocation flags and lifetime to context constraints.
Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

linux/refcount.h
linux/types.h
linux/blkdev.h
linux/magic.h
linux/jbd2.h
linux/quota.h
linux/rwsem.h
linux/rbtree.h
linux/seqlock.h
linux/mutex.h
linux/timer.h
linux/sched/signal.h
linux/blockgroup_lock.h
linux/percpu_counter.h
linux/ratelimit.h
linux/crc32c.h
linux/falloc.h
linux/percpu-rwsem.h
linux/fiemap.h
linux/compat.h
uapi/linux/ext4.h
linux/fscrypt.h
linux/fsverity.h
linux/compiler.h
extents_status.h
fast_commit.h

Detected Declarations

struct ext4_allocation_request
struct ext4_map_blocks
struct ext4_system_blocks
struct ext4_io_end_vec
struct ext4_io_submit
struct ext4_group_desc
struct flex_groups
struct compat_ext4_new_group_input
struct ext4_new_group_data
struct ext4_inode
struct ext4_fc_inode_snap
struct ext4_inode_info
struct ext4_super_block
struct ext4_journal_trigger
struct ext4_orphan_block_tail
struct ext4_orphan_block
struct ext4_orphan_info
struct ext4_fc_snap_stats
struct ext4_sb_info
struct ext4_dir_entry
struct ext4_dir_entry_hash
struct ext4_dir_entry_2
struct ext4_dir_entry_tail
struct dx_hash_info
struct ext4_filename
struct ext4_iloc
struct dir_private_info
struct ext4_lazy_init
struct ext4_li_request
struct ext4_features
struct mmp_struct
struct mmpd_data
struct ext4_group_info
struct iomap
struct ext4_ext_path
struct ext4_extent
enum SHIFT_DIRECTION
enum criteria
enum ext4_fc_snap_err
enum ext4_journal_trigger_type
enum ext4_li_mode
function ext4_mask_flags
function ext4_check_flag_values
function inodes
function ext4_decode_extra_time
function EXT4_INODE_SET_XTIME_VAL
function ext4_inodes_per_orphan_block
function ext4_writepages_down_read

Annotated Snippet

extern const struct file_operations ext4_dir_operations;

/* file.c */
extern const struct inode_operations ext4_file_inode_operations;
extern const struct file_operations ext4_file_operations;
extern loff_t ext4_llseek(struct file *file, loff_t offset, int origin);

/* inline.c */
extern int ext4_get_max_inline_size(struct inode *inode);
extern int ext4_find_inline_data_nolock(struct inode *inode);
extern int ext4_destroy_inline_data(handle_t *handle, struct inode *inode);
extern void ext4_update_final_de(void *de_buf, int old_size, int new_size);

int ext4_readpage_inline(struct inode *inode, struct folio *folio);
extern int ext4_try_to_write_inline_data(struct address_space *mapping,
					 struct inode *inode,
					 loff_t pos, unsigned len,
					 struct folio **foliop);
int ext4_write_inline_data_end(struct inode *inode, loff_t pos, unsigned len,
			       unsigned copied, struct folio *folio);
extern int ext4_generic_write_inline_data(struct address_space *mapping,
					  struct inode *inode,
					  loff_t pos, unsigned len,
					  struct folio **foliop,
					  void **fsdata, bool da);
extern int ext4_try_add_inline_entry(handle_t *handle,
				     struct ext4_filename *fname,
				     struct inode *dir, struct inode *inode);
extern int ext4_try_create_inline_dir(handle_t *handle,
				      struct inode *parent,
				      struct inode *inode);
extern int ext4_read_inline_dir(struct file *filp,
				struct dir_context *ctx,
				int *has_inline_data);
extern int ext4_inlinedir_to_tree(struct file *dir_file,
				  struct inode *dir, ext4_lblk_t block,
				  struct dx_hash_info *hinfo,
				  __u32 start_hash, __u32 start_minor_hash,
				  int *has_inline_data);
extern struct buffer_head *ext4_find_inline_entry(struct inode *dir,
					struct ext4_filename *fname,
					struct ext4_dir_entry_2 **res_dir,
					int *has_inline_data);
extern int ext4_delete_inline_entry(handle_t *handle,
				    struct inode *dir,
				    struct ext4_dir_entry_2 *de_del,
				    struct buffer_head *bh,
				    int *has_inline_data);
extern bool empty_inline_dir(struct inode *dir, int *has_inline_data);
extern struct buffer_head *ext4_get_first_inline_block(struct inode *inode,
					struct ext4_dir_entry_2 **parent_de,
					int *retval);
extern void *ext4_read_inline_link(struct inode *inode);

struct iomap;
extern int ext4_inline_data_iomap(struct inode *inode, struct iomap *iomap);

extern int ext4_inline_data_truncate(struct inode *inode, int *has_inline);

extern int ext4_convert_inline_data(struct inode *inode);

static inline int ext4_has_inline_data(struct inode *inode)
{
	return ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA) &&
	       EXT4_I(inode)->i_inline_off;
}

/* namei.c */
extern const struct inode_operations ext4_dir_inode_operations;
extern const struct inode_operations ext4_special_inode_operations;
extern struct dentry *ext4_get_parent(struct dentry *child);
extern int ext4_init_dirblock(handle_t *handle, struct inode *inode,
			      struct buffer_head *dir_block,
			      unsigned int parent_ino, void *inline_buf,
			      int inline_size);
extern void ext4_initialize_dirent_tail(struct buffer_head *bh,
					unsigned int blocksize);
extern int ext4_handle_dirty_dirblock(handle_t *handle, struct inode *inode,
				      struct buffer_head *bh);
extern int __ext4_unlink(struct inode *dir, const struct qstr *d_name,
			 struct inode *inode, struct dentry *dentry);
extern int __ext4_link(struct inode *dir, struct inode *inode,
		       const struct qstr *d_name, struct dentry *dentry);

#define S_SHIFT 12
static const unsigned char ext4_type_by_mode[(S_IFMT >> S_SHIFT) + 1] = {
	[S_IFREG >> S_SHIFT]	= EXT4_FT_REG_FILE,
	[S_IFDIR >> S_SHIFT]	= EXT4_FT_DIR,
	[S_IFCHR >> S_SHIFT]	= EXT4_FT_CHRDEV,
	[S_IFBLK >> S_SHIFT]	= EXT4_FT_BLKDEV,

Annotation

Immediate include surface: `linux/refcount.h`, `linux/types.h`, `linux/blkdev.h`, `linux/magic.h`, `linux/jbd2.h`, `linux/quota.h`, `linux/rwsem.h`, `linux/rbtree.h`.
Detected declarations: `struct ext4_allocation_request`, `struct ext4_map_blocks`, `struct ext4_system_blocks`, `struct ext4_io_end_vec`, `struct ext4_io_submit`, `struct ext4_group_desc`, `struct flex_groups`, `struct compat_ext4_new_group_input`, `struct ext4_new_group_data`, `struct ext4_inode`.
Atlas domain: Core OS / VFS And Filesystem Core.
Implementation status: pattern implementation candidate.
Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

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.