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Date: Thu, 10 Dec 2020 17:53:57 -0300
From: Gabriel Krisman Bertazi <krisman@...labora.com>
To: Arnaud Ferraris <arnaud.ferraris@...labora.com>
Cc: linux-ext4@...r.kernel.org, drosen@...gle.com, ebiggers@...nel.org,
tytso@....edu
Subject: Re: [PATCH RESEND v2 07/12] e2fsck: Support casefold directories
when rehashing
Arnaud Ferraris <arnaud.ferraris@...labora.com> writes:
> From: Gabriel Krisman Bertazi <krisman@...labora.com>
>
> When rehashing a +F directory, the casefold comparison needs to be
> performed, in order to identify duplicated filenames. Like the -F
> version, This is done in two steps, first adapt the qsort comparison to
> consider casefolded directories, and then iterate over the sorted list
> fixing dups.
>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>
> Signed-off-by: Arnaud Ferraris <arnaud.ferraris@...labora.com>
> ---
> e2fsck/rehash.c | 88 ++++++++++++++++++++++++++++++++++++++++---------
> 1 file changed, 72 insertions(+), 16 deletions(-)
>
> diff --git a/e2fsck/rehash.c b/e2fsck/rehash.c
> index 30e510a6..14215011 100644
> --- a/e2fsck/rehash.c
> +++ b/e2fsck/rehash.c
> @@ -214,6 +214,23 @@ static EXT2_QSORT_TYPE ino_cmp(const void *a, const void *b)
> return (he_a->ino - he_b->ino);
> }
>
> +struct name_cmp_ctx
> +{
> + int casefold;
> + const struct ext2fs_nls_table *tbl;
> +};
> +
> +
> +static int same_name(const struct name_cmp_ctx *cmp_ctx, char *s1,
> + int len1, char *s2, int len2)
> +{
> + if (!cmp_ctx->casefold)
> + return (len1 == len2 && !memcmp(s1, s2, len1));
> + else
> + return !ext2fs_casefold_cmp(cmp_ctx->tbl,
> + s1, len1, s2, len2);
> +}
> +
> /* Used for sorting the hash entry */
> static EXT2_QSORT_TYPE name_cmp(const void *a, const void *b)
> {
> @@ -240,9 +257,35 @@ static EXT2_QSORT_TYPE name_cmp(const void *a, const void *b)
> return ret;
> }
>
> +static EXT2_QSORT_TYPE name_cf_cmp(const struct name_cmp_ctx *ctx,
> + const void *a, const void *b)
> +{
> + const struct hash_entry *he_a = (const struct hash_entry *) a;
> + const struct hash_entry *he_b = (const struct hash_entry *) b;
> + unsigned int he_a_len, he_b_len, min_len;
> + int ret;
> +
> + he_a_len = ext2fs_dirent_name_len(he_a->dir);
> + he_b_len = ext2fs_dirent_name_len(he_b->dir);
> +
> + ret = ext2fs_casefold_cmp(ctx->tbl, he_a->dir->name, he_a_len,
> + he_b->dir->name, he_b_len);
> + if (ret == 0) {
> + if (he_a_len > he_b_len)
> + ret = 1;
> + else if (he_a_len < he_b_len)
> + ret = -1;
> + else
> + ret = he_b->dir->inode - he_a->dir->inode;
> + }
> + return ret;
> +}
> +
> +
extra line
> /* Used for sorting the hash entry */
> -static EXT2_QSORT_TYPE hash_cmp(const void *a, const void *b)
> +static EXT2_QSORT_TYPE hash_cmp(const void *a, const void *b, void *arg)
> {
> + const struct name_cmp_ctx *ctx = (struct name_cmp_ctx *) arg;
> const struct hash_entry *he_a = (const struct hash_entry *) a;
> const struct hash_entry *he_b = (const struct hash_entry *) b;
> int ret;
> @@ -256,8 +299,12 @@ static EXT2_QSORT_TYPE hash_cmp(const void *a, const void *b)
> ret = 1;
> else if (he_a->minor_hash < he_b->minor_hash)
> ret = -1;
> - else
> - ret = name_cmp(a, b);
> + else {
> + if (ctx->casefold)
> + ret = name_cf_cmp(ctx, a, b);
> + else
> + ret = name_cmp(a, b);
> + }
> }
> return ret;
> }
> @@ -380,7 +427,8 @@ static void mutate_name(char *str, unsigned int *len)
>
> static int duplicate_search_and_fix(e2fsck_t ctx, ext2_filsys fs,
> ext2_ino_t ino,
> - struct fill_dir_struct *fd)
> + struct fill_dir_struct *fd,
> + const struct name_cmp_ctx *cmp_ctx)
> {
> struct problem_context pctx;
> struct hash_entry *ent, *prev;
> @@ -403,11 +451,12 @@ static int duplicate_search_and_fix(e2fsck_t ctx, ext2_filsys fs,
> ent = fd->harray + i;
> prev = ent - 1;
> if (!ent->dir->inode ||
> - (ext2fs_dirent_name_len(ent->dir) !=
> - ext2fs_dirent_name_len(prev->dir)) ||
> - memcmp(ent->dir->name, prev->dir->name,
> - ext2fs_dirent_name_len(ent->dir)))
> + !same_name(cmp_ctx, ent->dir->name,
> + ext2fs_dirent_name_len(ent->dir),
> + prev->dir->name,
> + ext2fs_dirent_name_len(prev->dir)))
> continue;
> +
noise.
Other than that, I think this is still good.
> pctx.dirent = ent->dir;
> if ((ent->dir->inode == prev->dir->inode) &&
> fix_problem(ctx, PR_2_DUPLICATE_DIRENT, &pctx)) {
> @@ -426,10 +475,11 @@ static int duplicate_search_and_fix(e2fsck_t ctx, ext2_filsys fs,
> mutate_name(new_name, &new_len);
> for (j=0; j < fd->num_array; j++) {
> if ((i==j) ||
> - (new_len !=
> - (unsigned) ext2fs_dirent_name_len(fd->harray[j].dir)) ||
> - memcmp(new_name, fd->harray[j].dir->name, new_len))
> + !same_name(cmp_ctx, new_name, new_len,
> + fd->harray[j].dir->name,
> + ext2fs_dirent_name_len(fd->harray[j].dir))) {
> continue;
> + }
> mutate_name(new_name, &new_len);
>
> j = -1;
> @@ -894,6 +944,7 @@ errcode_t e2fsck_rehash_dir(e2fsck_t ctx, ext2_ino_t ino,
> struct fill_dir_struct fd = { NULL, NULL, 0, 0, 0, NULL,
> 0, 0, 0, 0, 0, 0 };
> struct out_dir outdir = { 0, 0, 0, 0 };
> + struct name_cmp_ctx name_cmp_ctx = {0, NULL};
>
> e2fsck_read_inode(ctx, ino, &inode, "rehash_dir");
>
> @@ -921,6 +972,11 @@ errcode_t e2fsck_rehash_dir(e2fsck_t ctx, ext2_ino_t ino,
> fd.compress = 1;
> fd.parent = 0;
>
> + if (fs->encoding && (inode.i_flags & EXT4_CASEFOLD_FL)) {
> + name_cmp_ctx.casefold = 1;
> + name_cmp_ctx.tbl = fs->encoding;
> + }
> +
> retry_nohash:
> /* Read in the entire directory into memory */
> retval = ext2fs_block_iterate3(fs, ino, 0, 0,
> @@ -949,16 +1005,16 @@ retry_nohash:
> /* Sort the list */
> resort:
> if (fd.compress && fd.num_array > 1)
> - qsort(fd.harray+2, fd.num_array-2, sizeof(struct hash_entry),
> - hash_cmp);
> + qsort_r(fd.harray+2, fd.num_array-2, sizeof(struct hash_entry),
> + hash_cmp, &name_cmp_ctx);
> else
> - qsort(fd.harray, fd.num_array, sizeof(struct hash_entry),
> - hash_cmp);
> + qsort_r(fd.harray, fd.num_array, sizeof(struct hash_entry),
> + hash_cmp, &name_cmp_ctx);
>
> /*
> * Look for duplicates
> */
> - if (duplicate_search_and_fix(ctx, fs, ino, &fd))
> + if (duplicate_search_and_fix(ctx, fs, ino, &fd, &name_cmp_ctx))
> goto resort;
>
> if (ctx->options & E2F_OPT_NO) {
--
Gabriel Krisman Bertazi
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