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Date: Sat, 31 Mar 2007 10:39:26 -0400
From: Theodore Tso <tytso@....edu>
To: Kalpak Shah <kalpak@...sterfs.com>,
linux-ext4 <linux-ext4@...r.kernel.org>,
Lustre-discuss <Lustre-discuss@...sterfs.com>
Subject: Re: [PATCH] Correction to check_filetype()
On Sat, Mar 31, 2007 at 08:35:09AM -0400, Theodore Tso wrote:
> And we can't really check the case where a directory gets turned into
> a regular file without destroying e2fsck's performance, since that
> would require reading the first block of every single file, and this
> also significantly increases the chance of false positives. So it's a
> lot of complexity for what seems to have always been an artificial
> test case.
OK, this is what I have done so far. Not checked in yet, but it looks
right to me. Note that this makes your testcase have a very booring
result. :-)
I'm going to let this one soak for a bit to make sure we don't pick up
any fase positives or negatives in the hueristics.
- Ted
diff -r 11d3e029aa83 e2fsck/message.c
--- a/e2fsck/message.c Thu Mar 29 00:32:23 2007 -0400
+++ b/e2fsck/message.c Sat Mar 31 10:36:55 2007 -0400
@@ -35,6 +35,7 @@
* %Id <inode> -> i_dir_acl
* %Iu <inode> -> i_uid
* %Ig <inode> -> i_gid
+ * %It <inode type>
* %j <ino2> inode number
* %m <com_err error message>
* %N <num>
@@ -310,6 +311,25 @@ static _INLINE_ void expand_inode_expres
printf("%d", (inode->i_gid |
(inode->osd2.linux2.l_i_gid_high << 16)));
break;
+ case 't':
+ if (LINUX_S_ISREG(inode->i_mode))
+ printf(_("regular file"));
+ else if (LINUX_S_ISDIR(inode->i_mode))
+ printf(_("directory"));
+ else if (LINUX_S_ISCHR(inode->i_mode))
+ printf(_("character device"));
+ else if (LINUX_S_ISBLK(inode->i_mode))
+ printf(_("block device"));
+ else if (LINUX_S_ISFIFO(inode->i_mode))
+ printf(_("named pipe"));
+ else if (LINUX_S_ISLNK(inode->i_mode))
+ printf(_("symbolic link"));
+ else if (LINUX_S_ISSOCK(inode->i_mode))
+ printf(_("socket"));
+ else
+ printf(_("unknown file type with mode 0%o"),
+ inode->i_mode);
+ break;
default:
no_inode:
printf("%%I%c", ch);
diff -r 11d3e029aa83 e2fsck/pass1.c
--- a/e2fsck/pass1.c Thu Mar 29 00:32:23 2007 -0400
+++ b/e2fsck/pass1.c Sat Mar 31 10:36:55 2007 -0400
@@ -133,11 +133,10 @@ int e2fsck_pass1_check_device_inode(ext2
int i;
/*
- * If i_blocks is non-zero, or the index flag is set, then
- * this is a bogus device/fifo/socket
+ * If the index flag is set, then this is a bogus
+ * device/fifo/socket
*/
- if ((ext2fs_inode_data_blocks(fs, inode) != 0) ||
- (inode->i_flags & EXT2_INDEX_FL))
+ if (inode->i_flags & EXT2_INDEX_FL)
return 0;
/*
@@ -370,6 +369,73 @@ static void check_inode_extra_space(e2fs
if (*eamagic == EXT2_EXT_ATTR_MAGIC) {
/* it seems inode has an extended attribute(s) in body */
check_ea_in_inode(ctx, pctx);
+ }
+}
+
+/*
+ * Check to see if the inode might really be a directory, despite i_mode
+ *
+ * This is a lot of complexity for something for which I'm not really
+ * convinced happens frequently in the wild. If for any reason this
+ * causes any problems, take this code out.
+ * [tytso:20070331.0827EDT]
+ */
+static void check_is_really_dir(e2fsck_t ctx, struct problem_context *pctx,
+ char *buf)
+{
+ struct ext2_inode *inode = pctx->inode;
+ int i, not_device = 0;
+ blk_t blk;
+ struct ext2_dir_entry *dirent;
+
+ if (LINUX_S_ISDIR(inode->i_mode) || LINUX_S_ISREG(inode->i_mode))
+ return;
+
+ for (i=0; i < EXT2_N_BLOCKS; i++) {
+ blk = inode->i_block[i];
+ if (!blk)
+ continue;
+ if (i >= 4)
+ not_device++;
+
+ if (blk < ctx->fs->super->s_first_data_block ||
+ blk >= ctx->fs->super->s_blocks_count ||
+ ext2fs_fast_test_block_bitmap(ctx->block_found_map, blk))
+ return; /* Invalid block, can't be dir */
+ }
+
+ if ((LINUX_S_ISCHR(inode->i_mode) || LINUX_S_ISBLK(inode->i_mode)) &&
+ (inode->i_links_count == 1) && !not_device)
+ return;
+
+ if (LINUX_S_ISLNK(inode->i_mode) && inode->i_links_count == 1)
+ return;
+
+ if (ext2fs_read_dir_block(ctx->fs, inode->i_block[0], buf))
+ return;
+
+ dirent = (struct ext2_dir_entry *) buf;
+ if (((dirent->name_len & 0xFF) != 1) ||
+ (dirent->name[0] != '.') ||
+ (dirent->inode != pctx->ino) ||
+ (dirent->rec_len < 12) ||
+ (dirent->rec_len % 4) ||
+ (dirent->rec_len >= ctx->fs->blocksize - 12))
+ return;
+
+ dirent = (struct ext2_dir_entry *) (buf + dirent->rec_len);
+ if (((dirent->name_len & 0xFF) != 2) ||
+ (dirent->name[0] != '.') ||
+ (dirent->name[1] != '.') ||
+ (dirent->rec_len < 12) ||
+ (dirent->rec_len % 4))
+ return;
+
+ if (fix_problem(ctx, PR_1_TREAT_AS_DIRECTORY, pctx)) {
+ inode->i_mode = (inode->i_mode & 07777) | LINUX_S_IFDIR;
+ e2fsck_write_inode_full(ctx, pctx->ino, inode,
+ EXT2_INODE_SIZE(ctx->fs->super),
+ "check_is_really_dir");
}
}
@@ -770,6 +836,7 @@ void e2fsck_pass1(e2fsck_t ctx)
}
check_inode_extra_space(ctx, &pctx);
+ check_is_really_dir(ctx, &pctx, block_buf);
if (LINUX_S_ISDIR(inode->i_mode)) {
ext2fs_mark_inode_bitmap(ctx->inode_dir_map, ino);
diff -r 11d3e029aa83 e2fsck/pass3.c
--- a/e2fsck/pass3.c Thu Mar 29 00:32:23 2007 -0400
+++ b/e2fsck/pass3.c Sat Mar 31 10:36:55 2007 -0400
@@ -645,6 +645,7 @@ static int fix_dotdot_proc(struct ext2_d
fix_problem(fp->ctx, PR_3_ADJUST_INODE, &pctx);
}
dirent->inode = fp->parent;
+ dirent->name_len = (dirent->name_len & 0xFF) | EXT2_FT_DIR << 8;
fp->done++;
return DIRENT_ABORT | DIRENT_CHANGED;
diff -r 11d3e029aa83 e2fsck/problem.c
--- a/e2fsck/problem.c Thu Mar 29 00:32:23 2007 -0400
+++ b/e2fsck/problem.c Sat Mar 31 10:36:55 2007 -0400
@@ -778,6 +778,11 @@ static struct e2fsck_problem problem_tab
{ PR_1_ATTR_HASH,
N_("@a in @i %i has a hash (%N) which is @n (must be 0)\n"),
PROMPT_CLEAR, PR_PREEN_OK },
+
+ /* inode appears to be a directory */
+ { PR_1_TREAT_AS_DIRECTORY,
+ N_("@i %i is a %It but it looks like it is really a directory\n"),
+ PROMPT_FIX, PR_PREEN_OK },
/* Pass 1b errors */
diff -r 11d3e029aa83 e2fsck/problem.h
--- a/e2fsck/problem.h Thu Mar 29 00:32:23 2007 -0400
+++ b/e2fsck/problem.h Sat Mar 31 10:36:55 2007 -0400
@@ -452,6 +452,9 @@ struct problem_context {
/* wrong EA hash value */
#define PR_1_ATTR_HASH 0x010054
+/* inode appears to be a directory */
+#define PR_1_TREAT_AS_DIRECTORY 0x010055
+
/*
* Pass 1b errors
*/
-
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