ping? This is a fairly nasty issue which should be fixed ASAP and go
into -stable.
On Fri, Nov 04, 2011 at 11:25:06AM -0400, Christoph Hellwig wrote:
> With Dmitry fsstress updates I've seen very reproducible crashes in
> xfs_attr_shortform_remove because xfs_attr_shortform_bytesfit claims that
> the attributes would not fit inline into the inode after removing an
> attribute. It turns out that we were operating on an inode with lots
> of delalloc extents, and thus an if_bytes values for the data fork that
> is larger than biggest possible on-disk storage for it which utterly
> confuses the code near the end of xfs_attr_shortform_bytesfit.
>
> Fix this by always allowing the current attribute fork, like we already
> do for the attr1 format, given that delalloc conversion will take care
> for moving either the data or attribute area out of line if it doesn't
> fit at that point - or making the point moot by merging extents at this
> point.
>
> Also document the function better, and clean up some lose bits.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
>
> Index: linux-2.6/fs/xfs/xfs_attr_leaf.c
> ===================================================================
> --- linux-2.6.orig/fs/xfs/xfs_attr_leaf.c 2011-11-04 13:46:59.481655134 +0100
> +++ linux-2.6/fs/xfs/xfs_attr_leaf.c 2011-11-04 15:58:06.480155275 +0100
> @@ -110,6 +110,7 @@ xfs_attr_namesp_match(int arg_flags, int
> /*
> * Query whether the requested number of additional bytes of extended
> * attribute space will be able to fit inline.
> + *
> * Returns zero if not, else the di_forkoff fork offset to be used in the
> * literal area for attribute data once the new bytes have been added.
> *
> @@ -136,11 +137,26 @@ xfs_attr_shortform_bytesfit(xfs_inode_t
> return (offset >= minforkoff) ? minforkoff : 0;
> }
>
> - if (!(mp->m_flags & XFS_MOUNT_ATTR2)) {
> - if (bytes <= XFS_IFORK_ASIZE(dp))
> - return dp->i_d.di_forkoff;
> + /*
> + * If the requested numbers of bytes is smaller or equal to the
> + * current attribute fork size we can always proceed.
> + *
> + * Note that if_bytes in the data fork might actually be larger than
> + * the current data fork size is due to delalloc extents. In that
> + * case either the extent count will go down when they are converted
> + * to ral extents, or the delalloc conversion will take care of the
> + * literal area rebalancing.
> + */
> + if (bytes <= XFS_IFORK_ASIZE(dp))
> + return dp->i_d.di_forkoff;
> +
> + /*
> + * For attr2 we can try to move the forkoff if there is space in the
> + * literal area, but for the old format we are done if there is no
> + * space in the fixes attribute fork.
> + */
> + if (!(mp->m_flags & XFS_MOUNT_ATTR2))
> return 0;
> - }
>
> dsize = dp->i_df.if_bytes;
>
> @@ -157,10 +173,9 @@ xfs_attr_shortform_bytesfit(xfs_inode_t
> xfs_default_attroffset(dp))
> dsize = XFS_BMDR_SPACE_CALC(MINDBTPTRS);
> break;
> -
> case XFS_DINODE_FMT_BTREE:
> /*
> - * If have data btree then keep forkoff if we have one,
> + * If have a data btree then keep forkoff if we have one,
> * otherwise we are adding a new attr, so then we set
> * minforkoff to where the btree root can finish so we have
> * plenty of room for attrs
> @@ -168,10 +183,9 @@ xfs_attr_shortform_bytesfit(xfs_inode_t
> if (dp->i_d.di_forkoff) {
> if (offset < dp->i_d.di_forkoff)
> return 0;
> - else
> - return dp->i_d.di_forkoff;
> - } else
> - dsize = XFS_BMAP_BROOT_SPACE(dp->i_df.if_broot);
> + return dp->i_d.di_forkoff;
> + }
> + dsize = XFS_BMAP_BROOT_SPACE(dp->i_df.if_broot);
> break;
> }
>
> @@ -186,10 +200,10 @@ xfs_attr_shortform_bytesfit(xfs_inode_t
> maxforkoff = XFS_LITINO(mp) - XFS_BMDR_SPACE_CALC(MINABTPTRS);
> maxforkoff = maxforkoff >> 3; /* rounded down */
>
> - if (offset >= minforkoff && offset < maxforkoff)
> - return offset;
> if (offset >= maxforkoff)
> return maxforkoff;
> + if (offset >= minforkoff)
> + return offset;
> return 0;
> }
>
>
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