lkml.org 
[lkml]   [2018]   [Dec]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] jffs2: make the overwritten xattr invisible after remount
From
Date
ping ?

On 2018/12/9 14:21, Hou Tao wrote:
> For xattr modification, we do not write a new jffs2_raw_xref with
> delete marker into flash, so if a xattr is modified then removed,
> and the old xref & xdatum are not erased by GC, after reboot or
> remount, the new xattr xref will be dead but the old xattr xref
> will be alive, and we will get the overwritten xattr instead of
> non-existent error when reading the removed xattr.
>
> Fix it by writing the deletion mark for xattr overwrite.
>
> Fixes: 8a13695cbe4e ("[JFFS2][XATTR] rid unnecessary writing of delete marker.")
> Signed-off-by: Hou Tao <houtao1@huawei.com>
> ---
> fs/jffs2/xattr.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 49 insertions(+), 6 deletions(-)
>
> diff --git a/fs/jffs2/xattr.c b/fs/jffs2/xattr.c
> index da3e18503c65..b2d6072f34af 100644
> --- a/fs/jffs2/xattr.c
> +++ b/fs/jffs2/xattr.c
> @@ -573,6 +573,15 @@ static struct jffs2_xattr_ref *create_xattr_ref(struct jffs2_sb_info *c, struct
> return ref; /* success */
> }
>
> +static void move_xattr_ref_to_dead_list(struct jffs2_sb_info *c,
> + struct jffs2_xattr_ref *ref)
> +{
> + spin_lock(&c->erase_completion_lock);
> + ref->next = c->xref_dead_list;
> + c->xref_dead_list = ref;
> + spin_unlock(&c->erase_completion_lock);
> +}
> +
> static void delete_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
> {
> /* must be called under down_write(xattr_sem) */
> @@ -582,10 +591,7 @@ static void delete_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *re
> ref->xseqno |= XREF_DELETE_MARKER;
> ref->ino = ref->ic->ino;
> ref->xid = ref->xd->xid;
> - spin_lock(&c->erase_completion_lock);
> - ref->next = c->xref_dead_list;
> - c->xref_dead_list = ref;
> - spin_unlock(&c->erase_completion_lock);
> + move_xattr_ref_to_dead_list(c, ref);
>
> dbg_xattr("xref(ino=%u, xid=%u, xseqno=%u) was removed.\n",
> ref->ino, ref->xid, ref->xseqno);
> @@ -1090,6 +1096,40 @@ int do_jffs2_getxattr(struct inode *inode, int xprefix, const char *xname,
> return rc;
> }
>
> +static void do_jffs2_delete_xattr_ref(struct jffs2_sb_info *c,
> + struct jffs2_xattr_ref *ref)
> +{
> + uint32_t request, length;
> + int err;
> + struct jffs2_xattr_datum *xd;
> +
> + request = PAD(sizeof(struct jffs2_raw_xref));
> + err = jffs2_reserve_space(c, request, &length,
> + ALLOC_NORMAL, JFFS2_SUMMARY_XREF_SIZE);
> + down_write(&c->xattr_sem);
> + if (err) {
> + JFFS2_WARNING("jffs2_reserve_space()=%d, request=%u\n",
> + err, request);
> + delete_xattr_ref(c, ref);
> + up_write(&c->xattr_sem);
> + return;
> + }
> +
> + xd = ref->xd;
> + ref->ino = ref->ic->ino;
> + ref->xid = xd->xid;
> + ref->xseqno |= XREF_DELETE_MARKER;
> + save_xattr_ref(c, ref);
> +
> + move_xattr_ref_to_dead_list(c, ref);
> + dbg_xattr("xref(ino=%u, xid=%u, xseqno=%u) was removed.\n",
> + ref->ino, ref->xid, ref->xseqno);
> + unrefer_xattr_datum(c, xd);
> +
> + up_write(&c->xattr_sem);
> + jffs2_complete_reservation(c);
> +}
> +
> int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname,
> const char *buffer, size_t size, int flags)
> {
> @@ -1097,7 +1137,7 @@ int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname,
> struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
> struct jffs2_inode_cache *ic = f->inocache;
> struct jffs2_xattr_datum *xd;
> - struct jffs2_xattr_ref *ref, *newref, **pref;
> + struct jffs2_xattr_ref *ref, *newref, *oldref, **pref;
> uint32_t length, request;
> int rc;
>
> @@ -1113,6 +1153,7 @@ int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname,
> return rc;
> }
>
> + oldref = NULL;
> /* Find existing xattr */
> down_write(&c->xattr_sem);
> retry:
> @@ -1196,11 +1237,13 @@ int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname,
> rc = PTR_ERR(newref);
> unrefer_xattr_datum(c, xd);
> } else if (ref) {
> - delete_xattr_ref(c, ref);
> + oldref = ref;
> }
> out:
> up_write(&c->xattr_sem);
> jffs2_complete_reservation(c);
> + if (oldref)
> + do_jffs2_delete_xattr_ref(c, oldref);
> return rc;
> }
>
>

\
 
 \ /
  Last update: 2018-12-15 14:25    [W:0.058 / U:25.616 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site