* [PATCH] ext4: check inline directory before converting
@ 2014-07-24 21:22 Darrick J. Wong
2014-07-24 22:41 ` Andreas Dilger
0 siblings, 1 reply; 3+ messages in thread
From: Darrick J. Wong @ 2014-07-24 21:22 UTC (permalink / raw)
To: Theodore Ts'o, darrick.wong, Zheng Liu; +Cc: linux-ext4
Before converting an inline directory to a regular directory, check
the directory entries to make sure they're not obviously broken.
This helps us to avoid a BUG_ON if one of the dirents is trashed.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/ext4/inline.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 645205d..c79d8e7 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -1157,6 +1157,31 @@ out:
return err;
}
+static int ext4_check_all_de(struct inode *dir, struct buffer_head *bh,
+ void *buf, int buf_size)
+{
+ struct ext4_dir_entry_2 *de;
+ int nlen, rlen;
+ unsigned int offset = 0;
+ char *top;
+
+ de = (struct ext4_dir_entry_2 *)buf;
+ top = buf + buf_size;
+ while ((char *) de < top) {
+ if (ext4_check_dir_entry(dir, NULL, de, bh,
+ buf, buf_size, offset))
+ return -EIO;
+ nlen = EXT4_DIR_REC_LEN(de->name_len);
+ rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
+ de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
+ offset += rlen;
+ }
+ if ((char *) de > top)
+ return -EIO;
+
+ return 0;
+}
+
static int ext4_convert_inline_data_nolock(handle_t *handle,
struct inode *inode,
struct ext4_iloc *iloc)
@@ -1178,6 +1203,18 @@ static int ext4_convert_inline_data_nolock(handle_t *handle,
if (error < 0)
goto out;
+ /*
+ * Make sure the inline directory entries pass checks before we try to
+ * convert them, so that we avoid touching stuff that needs fsck.
+ */
+ if (S_ISDIR(inode->i_mode)) {
+ error = ext4_check_all_de(inode, iloc->bh,
+ buf + EXT4_INLINE_DOTDOT_SIZE,
+ inline_size - EXT4_INLINE_DOTDOT_SIZE);
+ if (error)
+ goto out;
+ }
+
error = ext4_destroy_inline_data_nolock(handle, inode);
if (error)
goto out;
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] ext4: check inline directory before converting
2014-07-24 21:22 [PATCH] ext4: check inline directory before converting Darrick J. Wong
@ 2014-07-24 22:41 ` Andreas Dilger
2014-07-24 22:57 ` Darrick J. Wong
0 siblings, 1 reply; 3+ messages in thread
From: Andreas Dilger @ 2014-07-24 22:41 UTC (permalink / raw)
To: Darrick J. Wong; +Cc: Theodore Ts'o, Zheng Liu, linux-ext4
[-- Attachment #1: Type: text/plain, Size: 2599 bytes --]
On Jul 24, 2014, at 3:22 PM, Darrick J. Wong <darrick.wong@oracle.com> wrote:
> Before converting an inline directory to a regular directory, check
> the directory entries to make sure they're not obviously broken.
> This helps us to avoid a BUG_ON if one of the dirents is trashed.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
> fs/ext4/inline.c | 37 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 37 insertions(+)
>
> diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
> index 645205d..c79d8e7 100644
> --- a/fs/ext4/inline.c
> +++ b/fs/ext4/inline.c
> @@ -1157,6 +1157,31 @@ out:
> return err;
> }
>
> +static int ext4_check_all_de(struct inode *dir, struct buffer_head *bh,
> + void *buf, int buf_size)
It would seem that this function would be useful in ext4_readdir(), which
open-codes something very similar? It might be better to locate this
function in ext4/dir.c since it doesn't appear to have anything specific
to do with inline directories.
Cheers, Andreas
> +{
> + struct ext4_dir_entry_2 *de;
> + int nlen, rlen;
> + unsigned int offset = 0;
> + char *top;
> +
> + de = (struct ext4_dir_entry_2 *)buf;
> + top = buf + buf_size;
> + while ((char *) de < top) {
> + if (ext4_check_dir_entry(dir, NULL, de, bh,
> + buf, buf_size, offset))
> + return -EIO;
> + nlen = EXT4_DIR_REC_LEN(de->name_len);
> + rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
> + de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
> + offset += rlen;
> + }
> + if ((char *) de > top)
> + return -EIO;
> +
> + return 0;
> +}
> +
> static int ext4_convert_inline_data_nolock(handle_t *handle,
> struct inode *inode,
> struct ext4_iloc *iloc)
> @@ -1178,6 +1203,18 @@ static int ext4_convert_inline_data_nolock(handle_t *handle,
> if (error < 0)
> goto out;
>
> + /*
> + * Make sure the inline directory entries pass checks before we try to
> + * convert them, so that we avoid touching stuff that needs fsck.
> + */
> + if (S_ISDIR(inode->i_mode)) {
> + error = ext4_check_all_de(inode, iloc->bh,
> + buf + EXT4_INLINE_DOTDOT_SIZE,
> + inline_size - EXT4_INLINE_DOTDOT_SIZE);
> + if (error)
> + goto out;
> + }
> +
> error = ext4_destroy_inline_data_nolock(handle, inode);
> if (error)
> goto out;
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
Cheers, Andreas
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^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] ext4: check inline directory before converting
2014-07-24 22:41 ` Andreas Dilger
@ 2014-07-24 22:57 ` Darrick J. Wong
0 siblings, 0 replies; 3+ messages in thread
From: Darrick J. Wong @ 2014-07-24 22:57 UTC (permalink / raw)
To: Andreas Dilger; +Cc: Theodore Ts'o, Zheng Liu, linux-ext4
On Thu, Jul 24, 2014 at 04:41:04PM -0600, Andreas Dilger wrote:
> On Jul 24, 2014, at 3:22 PM, Darrick J. Wong <darrick.wong@oracle.com> wrote:
> > Before converting an inline directory to a regular directory, check
> > the directory entries to make sure they're not obviously broken.
> > This helps us to avoid a BUG_ON if one of the dirents is trashed.
> >
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> > fs/ext4/inline.c | 37 +++++++++++++++++++++++++++++++++++++
> > 1 file changed, 37 insertions(+)
> >
> > diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
> > index 645205d..c79d8e7 100644
> > --- a/fs/ext4/inline.c
> > +++ b/fs/ext4/inline.c
> > @@ -1157,6 +1157,31 @@ out:
> > return err;
> > }
> >
> > +static int ext4_check_all_de(struct inode *dir, struct buffer_head *bh,
> > + void *buf, int buf_size)
>
> It would seem that this function would be useful in ext4_readdir(), which
> open-codes something very similar? It might be better to locate this
> function in ext4/dir.c since it doesn't appear to have anything specific
> to do with inline directories.
I don't have any problem with moving it to dir.c.
As for _readdir, while it does open-code a similar loop, I don't know if it's
really worth it to try to shoe-horn what it does into the same function, since
it has to update ctx->pos and call dir_emit when it finds a valid entry.
Assuming you're talking about the while loop towards the end of the function.
--D
>
> Cheers, Andreas
>
> > +{
> > + struct ext4_dir_entry_2 *de;
> > + int nlen, rlen;
> > + unsigned int offset = 0;
> > + char *top;
> > +
> > + de = (struct ext4_dir_entry_2 *)buf;
> > + top = buf + buf_size;
> > + while ((char *) de < top) {
> > + if (ext4_check_dir_entry(dir, NULL, de, bh,
> > + buf, buf_size, offset))
> > + return -EIO;
> > + nlen = EXT4_DIR_REC_LEN(de->name_len);
> > + rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
> > + de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
> > + offset += rlen;
> > + }
> > + if ((char *) de > top)
> > + return -EIO;
> > +
> > + return 0;
> > +}
> > +
> > static int ext4_convert_inline_data_nolock(handle_t *handle,
> > struct inode *inode,
> > struct ext4_iloc *iloc)
> > @@ -1178,6 +1203,18 @@ static int ext4_convert_inline_data_nolock(handle_t *handle,
> > if (error < 0)
> > goto out;
> >
> > + /*
> > + * Make sure the inline directory entries pass checks before we try to
> > + * convert them, so that we avoid touching stuff that needs fsck.
> > + */
> > + if (S_ISDIR(inode->i_mode)) {
> > + error = ext4_check_all_de(inode, iloc->bh,
> > + buf + EXT4_INLINE_DOTDOT_SIZE,
> > + inline_size - EXT4_INLINE_DOTDOT_SIZE);
> > + if (error)
> > + goto out;
> > + }
> > +
> > error = ext4_destroy_inline_data_nolock(handle, inode);
> > if (error)
> > goto out;
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
>
>
> Cheers, Andreas
>
>
>
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2014-07-24 21:22 [PATCH] ext4: check inline directory before converting Darrick J. Wong
2014-07-24 22:41 ` Andreas Dilger
2014-07-24 22:57 ` Darrick J. Wong
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