Commit 233f4e12 authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: add parent pointer ioctls 



This patch adds a pair of new file ioctls to retrieve the parent pointer
of a given inode.  They both return the same results, but one operates
on the file descriptor passed to ioctl() whereas the other allows the
caller to specify a file handle for which the caller wants results.

Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent b8c9d425

fs/xfs/libxfs/xfs_fs.h

+74 −0
Original line number Diff line number Diff line
@@ -816,6 +816,78 @@ struct xfs_exchange_range { 
					 XFS_EXCHANGE_RANGE_DRY_RUN | \

					 XFS_EXCHANGE_RANGE_FILE1_WRITTEN)



/* Iterating parent pointers of files. */



/* target was the root directory */

#define XFS_GETPARENTS_OFLAG_ROOT	(1U << 0)



/* Cursor is done iterating pptrs */

#define XFS_GETPARENTS_OFLAG_DONE	(1U << 1)



#define XFS_GETPARENTS_OFLAGS_ALL	(XFS_GETPARENTS_OFLAG_ROOT | \

					 XFS_GETPARENTS_OFLAG_DONE)



#define XFS_GETPARENTS_IFLAGS_ALL	(0)



struct xfs_getparents_rec {

	struct xfs_handle	gpr_parent; /* Handle to parent */

	__u32			gpr_reclen; /* Length of entire record */

	__u32			gpr_reserved; /* zero */

	char			gpr_name[]; /* Null-terminated filename */

};



/* Iterate through this file's directory parent pointers */

struct xfs_getparents {

	/*

	 * Structure to track progress in iterating the parent pointers.

	 * Must be initialized to zeroes before the first ioctl call, and

	 * not touched by callers after that.

	 */

	struct xfs_attrlist_cursor	gp_cursor;



	/* Input flags: XFS_GETPARENTS_IFLAG* */

	__u16				gp_iflags;



	/* Output flags: XFS_GETPARENTS_OFLAG* */

	__u16				gp_oflags;



	/* Size of the gp_buffer in bytes */

	__u32				gp_bufsize;



	/* Must be set to zero */

	__u64				gp_reserved;



	/* Pointer to a buffer in which to place xfs_getparents_rec */

	__u64				gp_buffer;

};



static inline struct xfs_getparents_rec *

xfs_getparents_first_rec(struct xfs_getparents *gp)

{

	return (struct xfs_getparents_rec *)(uintptr_t)gp->gp_buffer;

}



static inline struct xfs_getparents_rec *

xfs_getparents_next_rec(struct xfs_getparents *gp,

			struct xfs_getparents_rec *gpr)

{

	void *next = ((void *)gpr + gpr->gpr_reclen);

	void *end = (void *)(uintptr_t)(gp->gp_buffer + gp->gp_bufsize);



	if (next >= end)

		return NULL;



	return next;

}



/* Iterate through this file handle's directory parent pointers. */

struct xfs_getparents_by_handle {

	/* Handle to file whose parents we want. */

	struct xfs_handle		gph_handle;



	struct xfs_getparents		gph_request;

};



/*

 * ioctl commands that are used by Linux filesystems

 */
@@ -851,6 +923,8 @@ struct xfs_exchange_range { 
/*	XFS_IOC_GETFSMAP ------ hoisted 59         */

#define XFS_IOC_SCRUB_METADATA	_IOWR('X', 60, struct xfs_scrub_metadata)

#define XFS_IOC_AG_GEOMETRY	_IOWR('X', 61, struct xfs_ag_geometry)

#define XFS_IOC_GETPARENTS	_IOWR('X', 62, struct xfs_getparents)

#define XFS_IOC_GETPARENTS_BY_HANDLE _IOWR('X', 63, struct xfs_getparents_by_handle)



/*

 * ioctl commands that replace IRIX syssgi()'s

fs/xfs/libxfs/xfs_ondisk.h

+5 −0
Original line number Diff line number Diff line
@@ -156,6 +156,11 @@ xfs_check_ondisk_structs(void) 
	XFS_CHECK_OFFSET(struct xfs_efi_log_format_32, efi_extents,	16);

	XFS_CHECK_OFFSET(struct xfs_efi_log_format_64, efi_extents,	16);



	/* parent pointer ioctls */

	XFS_CHECK_STRUCT_SIZE(struct xfs_getparents_rec,	32);

	XFS_CHECK_STRUCT_SIZE(struct xfs_getparents,		40);

	XFS_CHECK_STRUCT_SIZE(struct xfs_getparents_by_handle,	64);



	/*

	 * The v5 superblock format extended several v4 header structures with

	 * additional data. While new fields are only accessible on v5

fs/xfs/libxfs/xfs_parent.c

+34 −0
Original line number Diff line number Diff line
@@ -257,3 +257,37 @@ xfs_parent_replacename( 
	xfs_attr_defer_add(&ppargs->args, XFS_ATTR_DEFER_REPLACE);

	return 0;

}



/*

 * Extract parent pointer information from any parent pointer xattr into

 * @parent_ino/gen.  The last two parameters can be NULL pointers.

 *

 * Returns 0 if this is not a parent pointer xattr at all; or -EFSCORRUPTED for

 * garbage.

 */

int

xfs_parent_from_attr(

	struct xfs_mount	*mp,

	unsigned int		attr_flags,

	const unsigned char	*name,

	unsigned int		namelen,

	const void		*value,

	unsigned int		valuelen,

	xfs_ino_t		*parent_ino,

	uint32_t		*parent_gen)

{

	const struct xfs_parent_rec	*rec = value;



	ASSERT(attr_flags & XFS_ATTR_PARENT);



	if (!xfs_parent_namecheck(attr_flags, name, namelen))

		return -EFSCORRUPTED;

	if (!xfs_parent_valuecheck(mp, value, valuelen))

		return -EFSCORRUPTED;



	if (parent_ino)

		*parent_ino = be64_to_cpu(rec->p_ino);

	if (parent_gen)

		*parent_gen = be32_to_cpu(rec->p_gen);

	return 0;

}

fs/xfs/libxfs/xfs_parent.h

+5 −0
Original line number Diff line number Diff line
@@ -91,4 +91,9 @@ int xfs_parent_replacename(struct xfs_trans *tp, 
		struct xfs_inode *new_dp, const struct xfs_name *new_name,

		struct xfs_inode *child);



int xfs_parent_from_attr(struct xfs_mount *mp, unsigned int attr_flags,

		const unsigned char *name, unsigned int namelen,

		const void *value, unsigned int valuelen,

		xfs_ino_t *parent_ino, uint32_t *parent_gen);



#endif /* __XFS_PARENT_H__ */

fs/xfs/xfs_export.c

+1 −1
Original line number Diff line number Diff line
@@ -102,7 +102,7 @@ xfs_fs_encode_fh( 
	return fileid_type;

}



STATIC struct inode *

struct inode *

xfs_nfs_get_inode(

	struct super_block	*sb,

	u64			ino,