Re: [PATCH 20/29] xfs: move the legacy xfs_attr_list to xfs_ioctl.c

Darrick J. Wong
2020-01-21T18:41:49Z

On Tue, Jan 14, 2020 at 09:10:42AM +0100, Christoph Hellwig wrote:
> The old xfs_attr_list code is only used by the attrlist by handle
> ioctl. Move it to xfs_ioctl.c with its user. Also move the
> attrlist and attrlist_ent structure to xfs_fs.h, as they are exposed
> user ABIs.

They weren't there already? Gross....

> They are used through libattr headers with the same name
> by at least xfsdump. Also document this relation so that it doesn't
> require a research project to figure out.

Shouldn't these two structures get a check in xfs_ondisk.h to make sure
that we don't accidentally break the structure size?

--D

> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/xfs/libxfs/xfs_attr.h | 23 --------
> fs/xfs/libxfs/xfs_fs.h | 26 +++++++++
> fs/xfs/xfs_attr_list.c | 115 ---------------------------------------
> fs/xfs/xfs_ioctl.c | 112 +++++++++++++++++++++++++++++++++++++-
> fs/xfs/xfs_ioctl.h | 12 ++--
> fs/xfs/xfs_ioctl32.c | 4 +-
> 6 files changed, 146 insertions(+), 146 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index 31c0ffde4f59..0e3c213f78ce 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -48,27 +48,6 @@ struct xfs_attr_list_context;
> */
> #define ATTR_MAX_VALUELEN (64*1024) /* max length of a value */
>
> -/*
> - * Define how lists of attribute names are returned to the user from
> - * the attr_list() call. A large, 32bit aligned, buffer is passed in
> - * along with its size. We put an array of offsets at the top that each
> - * reference an attrlist_ent_t and pack the attrlist_ent_t's at the bottom.
> - */
> -typedef struct attrlist {
> - __s32 al_count; /* number of entries in attrlist */
> - __s32 al_more; /* T/F: more attrs (do call again) */
> - __s32 al_offset[1]; /* byte offsets of attrs [var-sized] */
> -} attrlist_t;
> -
> -/*
> - * Show the interesting info about one attribute. This is what the
> - * al_offset[i] entry points to.
> - */
> -typedef struct attrlist_ent { /* data from attr_list() */
> - __u32 a_valuelen; /* number bytes in value of attr */
> - char a_name[1]; /* attr name (NULL terminated) */
> -} attrlist_ent_t;
> -
> /*
> * Kernel-internal version of the attrlist cursor.
> */
> @@ -131,8 +110,6 @@ int xfs_attr_get(struct xfs_da_args *args);
> int xfs_attr_set(struct xfs_da_args *args);
> int xfs_attr_set_args(struct xfs_da_args *args);
> int xfs_attr_remove_args(struct xfs_da_args *args);
> -int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
> - int flags, struct attrlist_cursor_kern *cursor);
> bool xfs_attr_namecheck(const void *name, size_t length);
>
> #endif /* __XFS_ATTR_H__ */
> diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
> index ef95ca07d084..2c2b6e2b58f4 100644
> --- a/fs/xfs/libxfs/xfs_fs.h
> +++ b/fs/xfs/libxfs/xfs_fs.h
> @@ -572,6 +572,32 @@ typedef struct xfs_attrlist_cursor {
> __u32 opaque[4];
> } xfs_attrlist_cursor_t;
>
> +/*
> + * Define how lists of attribute names are returned to the user from
> + * the attr_list() call. A large, 32bit aligned, buffer is passed in
> + * along with its size. We put an array of offsets at the top that each
> + * reference an attrlist_ent_t and pack the attrlist_ent_t's at the bottom.
> + *
> + * NOTE: struct xfs_attrlist must match struct attrlist defined in libattr.
> + */
> +struct xfs_attrlist {
> + __s32 al_count; /* number of entries in attrlist */
> + __s32 al_more; /* T/F: more attrs (do call again) */
> + __s32 al_offset[1]; /* byte offsets of attrs [var-sized] */
> +};
> +
> +/*
> + * Show the interesting info about one attribute. This is what the
> + * al_offset[i] entry points to.
> + *
> + * NOTE: struct xfs_attrlist_ent must match struct attrlist_ent defined in
> + * libattr.
> + */
> +struct xfs_attrlist_ent { /* data from attr_list() */
> + __u32 a_valuelen; /* number bytes in value of attr */
> + char a_name[1]; /* attr name (NULL terminated) */
> +};
> +
> typedef struct xfs_fsop_attrlist_handlereq {
> struct xfs_fsop_handlereq hreq; /* handle interface structure */
> struct xfs_attrlist_cursor pos; /* opaque cookie, list offset */
> diff --git a/fs/xfs/xfs_attr_list.c b/fs/xfs/xfs_attr_list.c
> index 7f08e417d131..369ce1d3dd45 100644
> --- a/fs/xfs/xfs_attr_list.c
> +++ b/fs/xfs/xfs_attr_list.c
> @@ -544,118 +544,3 @@ xfs_attr_list_int(
> xfs_iunlock(dp, lock_mode);
> return error;
> }
> -
> -#define ATTR_ENTSIZE(namelen) /* actual bytes used by an attr */ \
> - ((offsetof(struct attrlist_ent, a_name) + \
> - (namelen) + 1 + sizeof(uint32_t) - 1) \
> - & ~(sizeof(uint32_t)-1))
> -
> -/*
> - * Format an attribute and copy it out to the user's buffer.
> - * Take care to check values and protect against them changing later,
> - * we may be reading them directly out of a user buffer.
> - */
> -STATIC void
> -xfs_attr_put_listent(
> - struct xfs_attr_list_context *context,
> - int flags,
> - unsigned char *name,
> - int namelen,
> - int valuelen)
> -{
> - struct attrlist *alist = context->buffer;
> - struct attrlist_ent *aep;
> - int arraytop;
> -
> - ASSERT(!context->seen_enough);
> - ASSERT(context->count >= 0);
> - ASSERT(context->count < (ATTR_MAX_VALUELEN/8));
> - ASSERT(context->firstu >= sizeof(*alist));
> - ASSERT(context->firstu <= context->bufsize);
> -
> - /*
> - * Only list entries in the right namespace.
> - */
> - if (((context->flags & ATTR_SECURE) == 0) !=
> - ((flags & XFS_ATTR_SECURE) == 0))
> - return;
> - if (((context->flags & ATTR_ROOT) == 0) !=
> - ((flags & XFS_ATTR_ROOT) == 0))
> - return;
> -
> - arraytop = sizeof(*alist) +
> - context->count * sizeof(alist->al_offset[0]);
> - context->firstu -= ATTR_ENTSIZE(namelen);
> - if (context->firstu < arraytop) {
> - trace_xfs_attr_list_full(context);
> - alist->al_more = 1;
> - context->seen_enough = 1;
> - return;
> - }
> -
> - aep = context->buffer + context->firstu;
> - aep->a_valuelen = valuelen;
> - memcpy(aep->a_name, name, namelen);
> - aep->a_name[namelen] = 0;
> - alist->al_offset[context->count++] = context->firstu;
> - alist->al_count = context->count;
> - trace_xfs_attr_list_add(context);
> - return;
> -}
> -
> -/*
> - * Generate a list of extended attribute names and optionally
> - * also value lengths. Positive return value follows the XFS
> - * convention of being an error, zero or negative return code
> - * is the length of the buffer returned (negated), indicating
> - * success.
> - */
> -int
> -xfs_attr_list(
> - struct xfs_inode *dp,
> - char *buffer,
> - int bufsize,
> - int flags,
> - struct attrlist_cursor_kern *cursor)
> -{
> - struct xfs_attr_list_context context;
> - struct attrlist *alist;
> - int error;
> -
> - /*
> - * Validate the cursor.
> - */
> - if (cursor->pad1 || cursor->pad2)
> - return -EINVAL;
> - if ((cursor->initted == 0) &&
> - (cursor->hashval || cursor->blkno || cursor->offset))
> - return -EINVAL;
> -
> - /*
> - * Check for a properly aligned buffer.
> - */
> - if (((long)buffer) & (sizeof(int)-1))
> - return -EFAULT;
> -
> - /*
> - * Initialize the output buffer.
> - */
> - memset(&context, 0, sizeof(context));
> - context.dp = dp;
> - context.cursor = cursor;
> - context.resynch = 1;
> - context.flags = flags;
> - context.buffer = buffer;
> - context.bufsize = (bufsize & ~(sizeof(int)-1)); /* align */
> - context.firstu = context.bufsize;
> - context.put_listent = xfs_attr_put_listent;
> -
> - alist = context.buffer;
> - alist->al_count = 0;
> - alist->al_more = 0;
> - alist->al_offset[0] = context.bufsize;
> -
> - error = xfs_attr_list_int(&context);
> - ASSERT(error <= 0);
> - return error;
> -}
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 9306cefa9e61..2e64dae3743f 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -35,6 +35,7 @@
> #include "xfs_health.h"
> #include "xfs_reflink.h"
> #include "xfs_ioctl.h"
> +#include "xfs_da_format.h"
>
> #include <linux/mount.h>
> #include <linux/namei.h>
> @@ -292,6 +293,113 @@ xfs_readlink_by_handle(
> return error;
> }
>
> +#define ATTR_ENTSIZE(namelen) /* actual bytes used by an attr */ \
> + ((offsetof(struct xfs_attrlist_ent, a_name) + \
> + (namelen) + 1 + sizeof(uint32_t) - 1) \
> + & ~(sizeof(uint32_t)-1))
> +
> +/*
> + * Format an attribute and copy it out to the user's buffer.
> + * Take care to check values and protect against them changing later,
> + * we may be reading them directly out of a user buffer.
> + */
> +static void
> +xfs_ioc_attr_put_listent(
> + struct xfs_attr_list_context *context,
> + int flags,
> + unsigned char *name,
> + int namelen,
> + int valuelen)
> +{
> + struct xfs_attrlist *alist = context->buffer;
> + struct xfs_attrlist_ent *aep;
> + int arraytop;
> +
> + ASSERT(!context->seen_enough);
> + ASSERT(context->count >= 0);
> + ASSERT(context->count < (ATTR_MAX_VALUELEN/8));
> + ASSERT(context->firstu >= sizeof(*alist));
> + ASSERT(context->firstu <= context->bufsize);
> +
> + /*
> + * Only list entries in the right namespace.
> + */
> + if (((context->flags & ATTR_SECURE) == 0) !=
> + ((flags & XFS_ATTR_SECURE) == 0))
> + return;
> + if (((context->flags & ATTR_ROOT) == 0) !=
> + ((flags & XFS_ATTR_ROOT) == 0))
> + return;
> +
> + arraytop = sizeof(*alist) +
> + context->count * sizeof(alist->al_offset[0]);
> + context->firstu -= ATTR_ENTSIZE(namelen);
> + if (context->firstu < arraytop) {
> + trace_xfs_attr_list_full(context);
> + alist->al_more = 1;
> + context->seen_enough = 1;
> + return;
> + }
> +
> + aep = context->buffer + context->firstu;
> + aep->a_valuelen = valuelen;
> + memcpy(aep->a_name, name, namelen);
> + aep->a_name[namelen] = 0;
> + alist->al_offset[context->count++] = context->firstu;
> + alist->al_count = context->count;
> + trace_xfs_attr_list_add(context);
> +}
> +
> +int
> +xfs_ioc_attr_list(
> + struct xfs_inode *dp,
> + char *buffer,
> + int bufsize,
> + int flags,
> + struct attrlist_cursor_kern *cursor)
> +{
> + struct xfs_attr_list_context context;
> + struct xfs_attrlist *alist;
> + int error;
> +
> + /*
> + * Validate the cursor.
> + */
> + if (cursor->pad1 || cursor->pad2)
> + return -EINVAL;
> + if ((cursor->initted == 0) &&
> + (cursor->hashval || cursor->blkno || cursor->offset))
> + return -EINVAL;
> +
> + /*
> + * Check for a properly aligned buffer.
> + */
> + if (((long)buffer) & (sizeof(int)-1))
> + return -EFAULT;
> +
> + /*
> + * Initialize the output buffer.
> + */
> + memset(&context, 0, sizeof(context));
> + context.dp = dp;
> + context.cursor = cursor;
> + context.resynch = 1;
> + context.flags = flags;
> + context.buffer = buffer;
> + context.bufsize = (bufsize & ~(sizeof(int)-1)); /* align */
> + context.firstu = context.bufsize;
> + context.put_listent = xfs_ioc_attr_put_listent;
> +
> + alist = context.buffer;
> + alist->al_count = 0;
> + alist->al_more = 0;
> + alist->al_offset[0] = context.bufsize;
> +
> + error = xfs_attr_list_int(&context);
> + ASSERT(error <= 0);
> + return error;
> +}
> +
> STATIC int
> xfs_attrlist_by_handle(
> struct file *parfilp,
> @@ -308,7 +416,7 @@ xfs_attrlist_by_handle(
> return -EPERM;
> if (copy_from_user(&al_hreq, arg, sizeof(xfs_fsop_attrlist_handlereq_t)))
> return -EFAULT;
> - if (al_hreq.buflen < sizeof(struct attrlist) ||
> + if (al_hreq.buflen < sizeof(struct xfs_attrlist) ||
> al_hreq.buflen > XFS_XATTR_LIST_MAX)
> return -EINVAL;
>
> @@ -327,7 +435,7 @@ xfs_attrlist_by_handle(
> goto out_dput;
>
> cursor = (attrlist_cursor_kern_t *)&al_hreq.pos;
> - error = xfs_attr_list(XFS_I(d_inode(dentry)), kbuf, al_hreq.buflen,
> + error = xfs_ioc_attr_list(XFS_I(d_inode(dentry)), kbuf, al_hreq.buflen,
> al_hreq.flags, cursor);
> if (error)
> goto out_kfree;
> diff --git a/fs/xfs/xfs_ioctl.h b/fs/xfs/xfs_ioctl.h
> index bb50cb3dc61f..cb7b94c576a7 100644
> --- a/fs/xfs/xfs_ioctl.h
> +++ b/fs/xfs/xfs_ioctl.h
> @@ -6,6 +6,12 @@
> #ifndef __XFS_IOCTL_H__
> #define __XFS_IOCTL_H__
>
> +struct attrlist_cursor_kern;
> +struct xfs_bstat;
> +struct xfs_ibulk;
> +struct xfs_inogrp;
> +
> +
> extern int
> xfs_ioc_space(
> struct file *filp,
> @@ -33,6 +39,8 @@ xfs_readlink_by_handle(
> int xfs_ioc_attrmulti_one(struct file *parfilp, struct inode *inode,
> uint32_t opcode, void __user *uname, void __user *value,
> uint32_t *len, uint32_t flags);
> +int xfs_ioc_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
> + int flags, struct attrlist_cursor_kern *cursor);
>
> extern struct dentry *
> xfs_handle_to_dentry(
> @@ -52,10 +60,6 @@ xfs_file_compat_ioctl(
> unsigned int cmd,
> unsigned long arg);
>
> -struct xfs_ibulk;
> -struct xfs_bstat;
> -struct xfs_inogrp;
> -
> int xfs_fsbulkstat_one_fmt(struct xfs_ibulk *breq,
> const struct xfs_bulkstat *bstat);
> int xfs_fsinumbers_fmt(struct xfs_ibulk *breq, const struct xfs_inumbers *igrp);
> diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
> index ee428ddf51e5..feb7bf07f315 100644
> --- a/fs/xfs/xfs_ioctl32.c
> +++ b/fs/xfs/xfs_ioctl32.c
> @@ -366,7 +366,7 @@ xfs_compat_attrlist_by_handle(
> if (copy_from_user(&al_hreq, arg,
> sizeof(compat_xfs_fsop_attrlist_handlereq_t)))
> return -EFAULT;
> - if (al_hreq.buflen < sizeof(struct attrlist) ||
> + if (al_hreq.buflen < sizeof(struct xfs_attrlist) ||
> al_hreq.buflen > XFS_XATTR_LIST_MAX)
> return -EINVAL;
>
> @@ -386,7 +386,7 @@ xfs_compat_attrlist_by_handle(
> goto out_dput;
>
> cursor = (attrlist_cursor_kern_t *)&al_hreq.pos;
> - error = xfs_attr_list(XFS_I(d_inode(dentry)), kbuf, al_hreq.buflen,
> + error = xfs_ioc_attr_list(XFS_I(d_inode(dentry)), kbuf, al_hreq.buflen,
> al_hreq.flags, cursor);
> if (error)
> goto out_kfree;
> --
> 2.24.1
>