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xfs: split out handle management helpers a bit

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Split out the functions that generate file/fs handles and map them back
into dentries in preparation for the GETPARENTS ioctl next.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Darrick J. Wong 2024-04-22 09:47:55 -07:00
parent af69d852df
commit b8c9d4253d
2 changed files with 70 additions and 32 deletions
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4
fs/xfs/libxfs/xfs_fs.h
View File

@ -633,7 +633,9 @@ typedef struct xfs_fsop_attrmulti_handlereq {
/*
* per machine unique filesystem identifier types.
*/
typedef struct { __u32 val[2]; } xfs_fsid_t; /* file system id type */
typedef struct xfs_fsid {
__u32 val[2]; /* file system id type */
} xfs_fsid_t;
typedef struct xfs_fid {
__u16 fid_len; /* length of remainder */

98
fs/xfs/xfs_handle.c
View File

@ -30,6 +30,42 @@
#include <linux/namei.h>
static inline size_t
xfs_filehandle_fid_len(void)
{
struct xfs_handle *handle = NULL;
return sizeof(struct xfs_fid) - sizeof(handle->ha_fid.fid_len);
}
static inline size_t
xfs_filehandle_init(
struct xfs_mount *mp,
xfs_ino_t ino,
uint32_t gen,
struct xfs_handle *handle)
{
memcpy(&handle->ha_fsid, mp->m_fixedfsid, sizeof(struct xfs_fsid));
handle->ha_fid.fid_len = xfs_filehandle_fid_len();
handle->ha_fid.fid_pad = 0;
handle->ha_fid.fid_gen = gen;
handle->ha_fid.fid_ino = ino;
return sizeof(struct xfs_handle);
}
static inline size_t
xfs_fshandle_init(
struct xfs_mount *mp,
struct xfs_handle *handle)
{
memcpy(&handle->ha_fsid, mp->m_fixedfsid, sizeof(struct xfs_fsid));
memset(&handle->ha_fid, 0, sizeof(handle->ha_fid));
return sizeof(struct xfs_fsid);
}
/*
* xfs_find_handle maps from userspace xfs_fsop_handlereq structure to
* a file or fs handle.
@ -84,20 +120,11 @@ xfs_find_handle(
memcpy(&handle.ha_fsid, ip->i_mount->m_fixedfsid, sizeof(xfs_fsid_t));
if (cmd == XFS_IOC_PATH_TO_FSHANDLE) {
/*
* This handle only contains an fsid, zero the rest.
*/
memset(&handle.ha_fid, 0, sizeof(handle.ha_fid));
hsize = sizeof(xfs_fsid_t);
} else {
handle.ha_fid.fid_len = sizeof(xfs_fid_t) -
sizeof(handle.ha_fid.fid_len);
handle.ha_fid.fid_pad = 0;
handle.ha_fid.fid_gen = inode->i_generation;
handle.ha_fid.fid_ino = ip->i_ino;
hsize = sizeof(xfs_handle_t);
}
if (cmd == XFS_IOC_PATH_TO_FSHANDLE)
hsize = xfs_fshandle_init(ip->i_mount, &handle);
else
hsize = xfs_filehandle_init(ip->i_mount, ip->i_ino,
inode->i_generation, &handle);
error = -EFAULT;
if (copy_to_user(hreq->ohandle, &handle, hsize) ||
@ -126,6 +153,31 @@ xfs_handle_acceptable(
return 1;
}
/* Convert handle already copied to kernel space into a dentry. */
static struct dentry *
xfs_khandle_to_dentry(
struct file *file,
struct xfs_handle *handle)
{
struct xfs_fid64 fid = {
.ino = handle->ha_fid.fid_ino,
.gen = handle->ha_fid.fid_gen,
};
/*
* Only allow handle opens under a directory.
*/
if (!S_ISDIR(file_inode(file)->i_mode))
return ERR_PTR(-ENOTDIR);
if (handle->ha_fid.fid_len != xfs_filehandle_fid_len())
return ERR_PTR(-EINVAL);
return exportfs_decode_fh(file->f_path.mnt, (struct fid *)&fid, 3,
FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG,
xfs_handle_acceptable, NULL);
}
/*
* Convert userspace handle data into a dentry.
*/
@ -136,29 +188,13 @@ xfs_handle_to_dentry(
u32 hlen)
{
xfs_handle_t handle;
struct xfs_fid64 fid;
/*
* Only allow handle opens under a directory.
*/
if (!S_ISDIR(file_inode(parfilp)->i_mode))
return ERR_PTR(-ENOTDIR);
if (hlen != sizeof(xfs_handle_t))
return ERR_PTR(-EINVAL);
if (copy_from_user(&handle, uhandle, hlen))
return ERR_PTR(-EFAULT);
if (handle.ha_fid.fid_len !=
sizeof(handle.ha_fid) - sizeof(handle.ha_fid.fid_len))
return ERR_PTR(-EINVAL);
memset(&fid, 0, sizeof(struct fid));
fid.ino = handle.ha_fid.fid_ino;
fid.gen = handle.ha_fid.fid_gen;
return exportfs_decode_fh(parfilp->f_path.mnt, (struct fid *)&fid, 3,
FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG,
xfs_handle_acceptable, NULL);
return xfs_khandle_to_dentry(parfilp, &handle);
}
STATIC struct dentry *