On Sun, May 6, 2018 at 7:24 PM, Allison Henderson
<allison.henderson@xxxxxxxxxx> wrote:
> This patch adds a new file ioctl to retrieve the parent
> pointer of a given inode
Looking through the patch I spotted some typos and use of outdated
names in comments.
> +#define XFS_PPTR_MAXNAMELEN 255
> +
> +/* return parents of the handle, not the open fd */
> +#define XFS_PPTR_IFLAG_HANDLE (1U << 0)
> +
> +/* Get an inode parent pointer through ioctl */
> +struct xfs_parent_ptr {
> + __u64 xpp_ino; /* Inode */
> + __u32 xpp_gen; /* Inode generation */
> + __u32 xpp_diroffset; /* Directory offset */
> + __u32 xpp_namelen; /* File name length */
> + __u8 xpp_name[XFS_PPTR_MAXNAMELEN]; /* File name */
> +};
> +
> +/* Iterate though an inodes parent pointers */
typo through
> +struct xfs_pptr_info {
> + struct xfs_handle pi_handle;
> + struct xfs_attrlist_cursor pi_cursor;
> + __u32 pi_flags;
> + __u32 pi_reserved;
> + __u32 pi_ptrs_size;
> + __u32 pi_ptrs_used;
> + __u64 pi_reserved2[6];
> +
> + /*
> + * An array of struct xfs_pptr follows the header
Should be struct xfs_parent_ptr
> + * information. Use XFS_PPINFO_TO_PP() to access the
> + * parent pointer array entries.
> + */
> +};
> +
> +#define XFS_PPTR_INFO_SIZEOF(nr_ptrs) sizeof (struct xfs_pptr_info) + \
> + nr_ptrs * sizeof(struct xfs_parent_ptr)
> +
> +#define XFS_PPINFO_TO_PP(info, idx) \
> + (&(((struct xfs_parent_ptr *)((char *)(info) + sizeof(*(info))))[(idx)]))
> +
> /*
> * ioctl limits
> */
> @@ -596,6 +633,7 @@ struct xfs_scrub_metadata {
> #define XFS_IOC_FREE_EOFBLOCKS _IOR ('X', 58, struct xfs_fs_eofblocks)
> /* XFS_IOC_GETFSMAP ------ hoisted 59 */
> #define XFS_IOC_SCRUB_METADATA _IOWR('X', 60, struct xfs_scrub_metadata)
> +#define XFS_IOC_GETPPOINTER _IOR ('X', 61, struct xfs_parent_ptr)
>
> /*
> * ioctl commands that replace IRIX syssgi()'s
> diff --git a/fs/xfs/libxfs/xfs_parent.c b/fs/xfs/libxfs/xfs_parent.c
> index e6de97c..61f1961 100644
> --- a/fs/xfs/libxfs/xfs_parent.c
> +++ b/fs/xfs/libxfs/xfs_parent.c
> @@ -32,6 +32,16 @@
> #include "xfs_attr_sf.h"
> #include "xfs_bmap.h"
>
> +/* Initializes a xfs_parent_ptr from an xfs_parent_name_rec */
> +void
> +xfs_init_parent_ptr(struct xfs_parent_ptr *xpp,
> + struct xfs_parent_name_rec *rec)
> +{
> + xpp->xpp_ino = be64_to_cpu(rec->p_ino);
> + xpp->xpp_gen = be32_to_cpu(rec->p_gen);
> + xpp->xpp_diroffset = be32_to_cpu(rec->p_diroffset);
> +}
> +
> /*
> * Parent pointer attribute handling.
> *
> diff --git a/fs/xfs/libxfs/xfs_parent.h b/fs/xfs/libxfs/xfs_parent.h
> index 298562b..1a321db 100644
> --- a/fs/xfs/libxfs/xfs_parent.h
> +++ b/fs/xfs/libxfs/xfs_parent.h
> @@ -33,4 +33,6 @@ int xfs_parent_add(struct xfs_trans *tp, struct xfs_inode *parent,
> struct xfs_inode *child, struct xfs_name *child_name,
> uint32_t diroffset, xfs_fsblock_t *firstblock,
> struct xfs_defer_ops *dfops);
> +void xfs_init_parent_ptr(struct xfs_parent_ptr *xpp,
> + struct xfs_parent_name_rec *rec);
> #endif /* __XFS_PARENT_H__ */
> diff --git a/fs/xfs/xfs_attr_list.c b/fs/xfs/xfs_attr_list.c
> index 3e59a34..bdbe9fb 100644
> --- a/fs/xfs/xfs_attr_list.c
> +++ b/fs/xfs/xfs_attr_list.c
> @@ -581,6 +581,9 @@ xfs_attr_put_listent(
> if (((context->flags & ATTR_ROOT) == 0) !=
> ((flags & XFS_ATTR_ROOT) == 0))
> return;
> + if (((context->flags & ATTR_PARENT) == 0) !=
> + ((flags & XFS_ATTR_PARENT) == 0))
> + return;
>
> arraytop = sizeof(*alist) +
> context->count * sizeof(alist->al_offset[0]);
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 844480a..ee544f2 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -46,6 +46,8 @@
> #include "xfs_fsmap.h"
> #include "scrub/xfs_scrub.h"
> #include "xfs_sb.h"
> +#include "xfs_da_format.h"
> +#include "xfs_parent_utils.h"
>
> #include <linux/capability.h>
> #include <linux/cred.h>
> @@ -1738,6 +1740,62 @@ xfs_ioc_scrub_metadata(
> return 0;
> }
>
> +/*
> + * IOCTL routine to get the parent pointer of an inode and return it to user
> + * space. Caller must pass an struct xfs_parent_name_irec with a name buffer
> + * large enough to hold the file name. Returns 0 on success or non-zero on
> + * failure
> + */
xfs_parent_name_irec should be xfs_pptr_info
> +STATIC int
> +xfs_ioc_get_parent_pointer(
> + struct file *filp,
> + void __user *arg)
> +{
> + struct xfs_inode *ip;
> + struct xfs_pptr_info *ppi;
> + struct dentry *dentry;
> + int error = 0;
> +
> + /* Allocate an xfs_pptr_info to put the user data */
> + ppi = kmem_alloc(sizeof(struct xfs_pptr_info), KM_SLEEP);
> + if (!ppi)
> + return -ENOMEM;
> +
> + /* Copy the data from the user */
> + copy_from_user(ppi, arg, sizeof(struct xfs_pptr_info));
> +
> + /*
> + * Now that we know how big the trailing buffer is, expand
> + * our kernel xfs_pptr_info to be the same size
> + */
> + ppi = kmem_realloc(ppi, XFS_PPTR_INFO_SIZEOF(ppi->pi_ptrs_size),
> + KM_SLEEP);
> + if (!ppi)
> + return -ENOMEM;
> +
> + if (ppi->pi_flags == XFS_PPTR_IFLAG_HANDLE) {
> + dentry = xfs_handle_to_dentry(filp, &ppi->pi_handle,
> + sizeof(struct xfs_handle));
> + if (IS_ERR(dentry))
> + return PTR_ERR(dentry);
> + ip = XFS_I(d_inode(dentry));
> + } else
> + ip = XFS_I(file_inode(filp));
> +
> + /* Get the parent pointers */
> + error = xfs_attr_get_parent_pointer(ip, ppi);
> +
> + if (error)
> + goto out;
> +
> + /* Copy the parent pointers back to the user */
> + copy_to_user(arg, ppi, XFS_PPTR_INFO_SIZEOF(ppi->pi_ptrs_size));
> +
> +out:
> + kmem_free(ppi);
> + return error;
> +}
> +
> int
> xfs_ioc_swapext(
> xfs_swapext_t *sxp)
> @@ -1894,7 +1952,8 @@ xfs_file_ioctl(
> return xfs_ioc_getxflags(ip, arg);
> case XFS_IOC_SETXFLAGS:
> return xfs_ioc_setxflags(ip, filp, arg);
> -
> + case XFS_IOC_GETPPOINTER:
> + return xfs_ioc_get_parent_pointer(filp, arg);
> case XFS_IOC_FSSETDM: {
> struct fsdmidata dmi;
>
> diff --git a/fs/xfs/xfs_parent_utils.c b/fs/xfs/xfs_parent_utils.c
> index 0fd48b8..1df003a 100644
> --- a/fs/xfs/xfs_parent_utils.c
> +++ b/fs/xfs/xfs_parent_utils.c
> @@ -68,3 +68,69 @@ xfs_parent_remove_deferred(
> ATTR_PARENT);
> }
>
> +/*
> + * Get the parent pointers for a given inode
> + *
> + * Returns 0 on success and non zero on error
> + */
> +int
> +xfs_attr_get_parent_pointer(struct xfs_inode *ip,
> + struct xfs_pptr_info *ppi)
> +
> +{
> +
> + struct attrlist *alist;
> + struct attrlist_ent *aent;
> + struct xfs_parent_ptr *xpp;
> + struct xfs_parent_name_rec *xpnr;
> + char *namebuf;
> + unsigned int namebuf_size;
> + int name_len;
> + int error = 0;
> + unsigned int flags = ATTR_PARENT;
> + int i;
> +
> + /* Allocate a buffer to store the attribute names */
> + namebuf_size = sizeof(struct attrlist) +
> + (ppi->pi_ptrs_size) * sizeof(struct attrlist_ent);
> + namebuf = kmem_zalloc_large(namebuf_size, KM_SLEEP);
> + if (!namebuf)
> + return -ENOMEM;
> +
> + error = xfs_attr_list(ip, namebuf, namebuf_size, flags,
> + (attrlist_cursor_kern_t *)&ppi->pi_cursor);
> + if (error)
> + goto out_kfree;
> +
> + alist = (struct attrlist *)namebuf;
> +
> + for (i = 0; i < alist->al_count; i++) {
> + xpp = XFS_PPINFO_TO_PP(ppi, i);
> + memset(xpp, 0, sizeof(struct xfs_parent_ptr));
> + aent = (struct attrlist_ent *) &namebuf[alist->al_offset[i]];
> + xpnr = (struct xfs_parent_name_rec *)(aent->a_name);
> +
> + if (aent->a_valuelen > XFS_PPTR_MAXNAMELEN) {
> + error = -ERANGE;
> + goto out_kfree;
> + }
> +
> + name_len = aent->a_valuelen;
> + error = xfs_attr_get(ip, (char *)xpnr,
> + sizeof(struct xfs_parent_name_rec),
> + (unsigned char *)(xpp->xpp_name),
> + &name_len, flags);
> + if (error)
> + goto out_kfree;
> +
> + xpp->xpp_namelen = name_len;
> + xfs_init_parent_ptr(xpp, xpnr);
> + }
> + ppi->pi_ptrs_used = alist->al_count;
> +
> +out_kfree:
> + kmem_free(namebuf);
> +
> + return error;
> +}
> +
> diff --git a/fs/xfs/xfs_parent_utils.h b/fs/xfs/xfs_parent_utils.h
> index 9e0ac13..33e3b2c 100644
> --- a/fs/xfs/xfs_parent_utils.h
> +++ b/fs/xfs/xfs_parent_utils.h
> @@ -27,4 +27,6 @@ int xfs_parent_remove_deferred(struct xfs_inode *parent,
> struct xfs_inode *child,
> xfs_dir2_dataptr_t diroffset,
> struct xfs_defer_ops *dfops);
> +int xfs_attr_get_parent_pointer(struct xfs_inode *ip,
> + struct xfs_pptr_info *ppi);
> #endif /* __XFS_PARENT_UTILS_H__ */
> --
> 2.7.4
>
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