From 48a71399e7477043ee25573b3df2505787fcf0c4 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 8 Nov 2019 15:05:35 -0800 Subject: [PATCH] xfs: cleanup __xfs_dir3_data_check Use an offset as the main means for iteration, and only do pointer arithmetics to find the data/unused entries. Signed-off-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/libxfs/xfs_dir2_data.c | 59 ++++++++++++++++++++--------------- 1 file changed, 33 insertions(+), 26 deletions(-) diff --git a/fs/xfs/libxfs/xfs_dir2_data.c b/fs/xfs/libxfs/xfs_dir2_data.c index 50e3fa092ff9..8c729270f9f1 100644 --- a/fs/xfs/libxfs/xfs_dir2_data.c +++ b/fs/xfs/libxfs/xfs_dir2_data.c @@ -23,6 +23,22 @@ static xfs_failaddr_t xfs_dir2_data_freefind_verify( struct xfs_dir2_data_unused *dup, struct xfs_dir2_data_free **bf_ent); +/* + * The number of leaf entries is limited by the size of the block and the amount + * of space used by the data entries. We don't know how much space is used by + * the data entries yet, so just ensure that the count falls somewhere inside + * the block right now. + */ +static inline unsigned int +xfs_dir2_data_max_leaf_entries( + const struct xfs_dir_ops *ops, + struct xfs_da_geometry *geo) +{ + return (geo->blksize - sizeof(struct xfs_dir2_block_tail) - + ops->data_entry_offset) / + sizeof(struct xfs_dir2_leaf_entry); +} + /* * Check the consistency of the data block. * The input can also be a block-format directory. @@ -38,23 +54,20 @@ __xfs_dir3_data_check( xfs_dir2_block_tail_t *btp=NULL; /* block tail */ int count; /* count of entries found */ xfs_dir2_data_hdr_t *hdr; /* data block header */ - xfs_dir2_data_entry_t *dep; /* data entry */ xfs_dir2_data_free_t *dfp; /* bestfree entry */ - xfs_dir2_data_unused_t *dup; /* unused entry */ - char *endp; /* end of useful data */ + void *endp; /* end of useful data */ int freeseen; /* mask of bestfrees seen */ xfs_dahash_t hash; /* hash of current name */ int i; /* leaf index */ int lastfree; /* last entry was unused */ xfs_dir2_leaf_entry_t *lep=NULL; /* block leaf entries */ struct xfs_mount *mp = bp->b_mount; - char *p; /* current data position */ int stale; /* count of stale leaves */ struct xfs_name name; + unsigned int offset; + unsigned int end; const struct xfs_dir_ops *ops; - struct xfs_da_geometry *geo; - - geo = mp->m_dir_geo; + struct xfs_da_geometry *geo = mp->m_dir_geo; /* * We can be passed a null dp here from a verifier, so we need to go the @@ -71,7 +84,7 @@ __xfs_dir3_data_check( return __this_address; hdr = bp->b_addr; - p = (char *)ops->data_entry_p(hdr); + offset = ops->data_entry_offset; switch (hdr->magic) { case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC): @@ -79,15 +92,8 @@ __xfs_dir3_data_check( btp = xfs_dir2_block_tail_p(geo, hdr); lep = xfs_dir2_block_leaf_p(btp); - /* - * The number of leaf entries is limited by the size of the - * block and the amount of space used by the data entries. - * We don't know how much space is used by the data entries yet, - * so just ensure that the count falls somewhere inside the - * block right now. - */ if (be32_to_cpu(btp->count) >= - ((char *)btp - p) / sizeof(struct xfs_dir2_leaf_entry)) + xfs_dir2_data_max_leaf_entries(ops, geo)) return __this_address; break; case cpu_to_be32(XFS_DIR3_DATA_MAGIC): @@ -99,6 +105,7 @@ __xfs_dir3_data_check( endp = xfs_dir3_data_endp(geo, hdr); if (!endp) return __this_address; + end = endp - bp->b_addr; /* * Account for zero bestfree entries. @@ -128,8 +135,10 @@ __xfs_dir3_data_check( /* * Loop over the data/unused entries. */ - while (p < endp) { - dup = (xfs_dir2_data_unused_t *)p; + while (offset < end) { + struct xfs_dir2_data_unused *dup = bp->b_addr + offset; + struct xfs_dir2_data_entry *dep = bp->b_addr + offset; + /* * If it's unused, look for the space in the bestfree table. * If we find it, account for that, else make sure it @@ -140,10 +149,10 @@ __xfs_dir3_data_check( if (lastfree != 0) return __this_address; - if (endp < p + be16_to_cpu(dup->length)) + if (offset + be16_to_cpu(dup->length) > end) return __this_address; if (be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) != - (char *)dup - (char *)hdr) + offset) return __this_address; fa = xfs_dir2_data_freefind_verify(hdr, bf, dup, &dfp); if (fa) @@ -158,7 +167,7 @@ __xfs_dir3_data_check( be16_to_cpu(bf[2].length)) return __this_address; } - p += be16_to_cpu(dup->length); + offset += be16_to_cpu(dup->length); lastfree = 1; continue; } @@ -168,15 +177,13 @@ __xfs_dir3_data_check( * in the leaf section of the block. * The linear search is crude but this is DEBUG code. */ - dep = (xfs_dir2_data_entry_t *)p; if (dep->namelen == 0) return __this_address; if (xfs_dir_ino_validate(mp, be64_to_cpu(dep->inumber))) return __this_address; - if (endp < p + ops->data_entsize(dep->namelen)) + if (offset + ops->data_entsize(dep->namelen) > end) return __this_address; - if (be16_to_cpu(*ops->data_entry_tag_p(dep)) != - (char *)dep - (char *)hdr) + if (be16_to_cpu(*ops->data_entry_tag_p(dep)) != offset) return __this_address; if (ops->data_get_ftype(dep) >= XFS_DIR3_FT_MAX) return __this_address; @@ -198,7 +205,7 @@ __xfs_dir3_data_check( if (i >= be32_to_cpu(btp->count)) return __this_address; } - p += ops->data_entsize(dep->namelen); + offset += ops->data_entsize(dep->namelen); } /* * Need to have seen all the entries and all the bestfree slots.