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Date: Sun, 15 Apr 2007 23:08:11 +0400
From: Evgeniy Dushistov <dushistov@...l.ru>
To: akpm@...ux-foundation.org, linux-kernel@...r.kernel.org
Cc: linux-fsdevel@...r.kernel.org
Subject: [PATCH]: ufs proper handling of zero link case
This patch should fix or partly fix this bug:
http://bugzilla.kernel.org/show_bug.cgi?id=8276
The problem is:
- if we see "zero link case" during reading inode operation,
we call ufs_error(which remount fs readonly), but not "mark" inode as
bad (1)
- in readonly case we do not fill some data structures, which are used
in read and write case (2)
- VFS call ufs_delete_inode if link count is zero (3)
so (1)->(3)->(2) cause oops, this patch should fix such scenario
Signed-off-by: Evgeniy Dushistov <dushistov@...l.ru>
Cc: Jim Paris <jim@...n.com>
---
Index: linux-2.6.21-rc6/fs/ufs/inode.c
===================================================================
--- linux-2.6.21-rc6.orig/fs/ufs/inode.c
+++ linux-2.6.21-rc6/fs/ufs/inode.c
@@ -601,7 +601,7 @@ static void ufs_set_inode_ops(struct ino
ufs_get_inode_dev(inode->i_sb, UFS_I(inode)));
}
-static void ufs1_read_inode(struct inode *inode, struct ufs_inode *ufs_inode)
+static int ufs1_read_inode(struct inode *inode, struct ufs_inode *ufs_inode)
{
struct ufs_inode_info *ufsi = UFS_I(inode);
struct super_block *sb = inode->i_sb;
@@ -613,8 +613,10 @@ static void ufs1_read_inode(struct inode
*/
inode->i_mode = mode = fs16_to_cpu(sb, ufs_inode->ui_mode);
inode->i_nlink = fs16_to_cpu(sb, ufs_inode->ui_nlink);
- if (inode->i_nlink == 0)
+ if (inode->i_nlink == 0) {
ufs_error (sb, "ufs_read_inode", "inode %lu has zero nlink\n", inode->i_ino);
+ return -1;
+ }
/*
* Linux now has 32-bit uid and gid, so we can support EFT.
@@ -643,9 +645,10 @@ static void ufs1_read_inode(struct inode
for (i = 0; i < (UFS_NDADDR + UFS_NINDIR) * 4; i++)
ufsi->i_u1.i_symlink[i] = ufs_inode->ui_u2.ui_symlink[i];
}
+ return 0;
}
-static void ufs2_read_inode(struct inode *inode, struct ufs2_inode *ufs2_inode)
+static int ufs2_read_inode(struct inode *inode, struct ufs2_inode *ufs2_inode)
{
struct ufs_inode_info *ufsi = UFS_I(inode);
struct super_block *sb = inode->i_sb;
@@ -658,8 +661,10 @@ static void ufs2_read_inode(struct inode
*/
inode->i_mode = mode = fs16_to_cpu(sb, ufs2_inode->ui_mode);
inode->i_nlink = fs16_to_cpu(sb, ufs2_inode->ui_nlink);
- if (inode->i_nlink == 0)
+ if (inode->i_nlink == 0) {
ufs_error (sb, "ufs_read_inode", "inode %lu has zero nlink\n", inode->i_ino);
+ return -1;
+ }
/*
* Linux now has 32-bit uid and gid, so we can support EFT.
@@ -690,6 +695,7 @@ static void ufs2_read_inode(struct inode
for (i = 0; i < (UFS_NDADDR + UFS_NINDIR) * 4; i++)
ufsi->i_u1.i_symlink[i] = ufs2_inode->ui_u2.ui_symlink[i];
}
+ return 0;
}
void ufs_read_inode(struct inode * inode)
@@ -698,6 +704,7 @@ void ufs_read_inode(struct inode * inode
struct super_block * sb;
struct ufs_sb_private_info * uspi;
struct buffer_head * bh;
+ int err;
UFSD("ENTER, ino %lu\n", inode->i_ino);
@@ -720,14 +727,17 @@ void ufs_read_inode(struct inode * inode
if ((UFS_SB(sb)->s_flags & UFS_TYPE_MASK) == UFS_TYPE_UFS2) {
struct ufs2_inode *ufs2_inode = (struct ufs2_inode *)bh->b_data;
- ufs2_read_inode(inode,
- ufs2_inode + ufs_inotofsbo(inode->i_ino));
+ err = ufs2_read_inode(inode,
+ ufs2_inode + ufs_inotofsbo(inode->i_ino));
} else {
struct ufs_inode *ufs_inode = (struct ufs_inode *)bh->b_data;
- ufs1_read_inode(inode, ufs_inode + ufs_inotofsbo(inode->i_ino));
+ err = ufs1_read_inode(inode,
+ ufs_inode + ufs_inotofsbo(inode->i_ino));
}
+ if (err)
+ goto bad_inode;
inode->i_version++;
ufsi->i_lastfrag =
(inode->i_size + uspi->s_fsize - 1) >> uspi->s_fshift;
@@ -888,6 +898,8 @@ void ufs_delete_inode (struct inode * in
loff_t old_i_size;
truncate_inode_pages(&inode->i_data, 0);
+ if (is_bad_inode(inode))
+ goto no_delete;
/*UFS_I(inode)->i_dtime = CURRENT_TIME;*/
lock_kernel();
mark_inode_dirty(inode);
@@ -898,4 +910,7 @@ void ufs_delete_inode (struct inode * in
ufs_warning(inode->i_sb, __FUNCTION__, "ufs_truncate failed\n");
ufs_free_inode (inode);
unlock_kernel();
+ return;
+no_delete:
+ clear_inode(inode); /* We must guarantee clearing of inode... */
}
--
/Evgeniy
-
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