Re: [PATCH RFC V2 1/1] ocfs2: reserve space for inline xattr before attaching reflink tree

From: Joseph Qi
Date: Wed Sep 11 2024 - 23:40:39 EST



On 9/12/24 11:14 AM, Gautham Ananthakrishna wrote:
> One of our customers reported a crash and a corrupted ocfs2 filesystem.
> The crash was due to the detection of corruption. Upon troubleshooting,
> the fsck -fn output showed the below corruption
>
> [EXTENT_LIST_FREE] Extent list in owner 33080590 claims 230 as the next free chain record,
> but fsck believes the largest valid value is 227. Clamp the next record value? n
>
> The stat output from the debugfs.ocfs2 showed the following corruption
> where the "Next Free Rec:" had overshot the "Count:" in the root metadata
> block.
>
> Inode: 33080590 Mode: 0640 Generation: 2619713622 (0x9c25a856)
> FS Generation: 904309833 (0x35e6ac49)
> CRC32: 00000000 ECC: 0000
> Type: Regular Attr: 0x0 Flags: Valid
> Dynamic Features: (0x16) HasXattr InlineXattr Refcounted
> Extended Attributes Block: 0 Extended Attributes Inline Size: 256
> User: 0 (root) Group: 0 (root) Size: 281320357888
> Links: 1 Clusters: 141738
> ctime: 0x66911b56 0x316edcb8 -- Fri Jul 12 06:02:30.829349048 2024
> atime: 0x66911d6b 0x7f7a28d -- Fri Jul 12 06:11:23.133669517 2024
> mtime: 0x66911b56 0x12ed75d7 -- Fri Jul 12 06:02:30.317552087 2024
> dtime: 0x0 -- Wed Dec 31 17:00:00 1969
> Refcount Block: 2777346
> Last Extblk: 2886943 Orphan Slot: 0
> Sub Alloc Slot: 0 Sub Alloc Bit: 14
> Tree Depth: 1 Count: 227 Next Free Rec: 230
> ## Offset Clusters Block#
> 0 0 2310 2776351
> 1 2310 2139 2777375
> 2 4449 1221 2778399
> 3 5670 731 2779423
> 4 6401 566 2780447
> ....... .... .......
> ....... .... .......
>
> The issue was in the reflink workfow while reserving space for inline xattr.
> The problematic function is ocfs2_reflink_xattr_inline(). By the time this
> function is called the reflink tree is already recreated at the destination
> inode from the source inode. At this point, this function reserves space
> space inline xattrs at the destination inode without even checking if there
> is space at the root metadata block. It simply reduces the l_count from 243
> to 227 thereby making space of 256 bytes for inline xattr whereas the inode
> already has extents beyond this index (in this case upto 230), thereby causing
> corruption.
>
> The fix for this is to reserve space for inline metadata before the at the
> destination inode before the reflink tree gets recreated. The customer has
> verified the fix.
>
> Fixes: ef962df057aa ("ocfs2: xattr: fix inlined xattr reflink")
> Cc: stable@xxxxxxxxxxxxxxx
>
> Signed-off-by: Gautham Ananthakrishna <gautham.ananthakrishna@xxxxxxxxxx>
> ---
> fs/ocfs2/refcounttree.c | 26 ++++++++++++++++++++++++--
> fs/ocfs2/xattr.c | 11 +----------
> 2 files changed, 25 insertions(+), 12 deletions(-)
>
> diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
> index 3f80a56d0d60..1d427da06bee 100644
> --- a/fs/ocfs2/refcounttree.c
> +++ b/fs/ocfs2/refcounttree.c
> @@ -25,6 +25,7 @@
> #include "namei.h"
> #include "ocfs2_trace.h"
> #include "file.h"
> +#include "symlink.h"
>
> #include <linux/bio.h>
> #include <linux/blkdev.h>
> @@ -4155,8 +4156,9 @@ static int __ocfs2_reflink(struct dentry *old_dentry,
> int ret;
> struct inode *inode = d_inode(old_dentry);
> struct buffer_head *new_bh = NULL;
> + struct ocfs2_inode_info *oi = OCFS2_I(inode);
>
> - if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_SYSTEM_FILE) {
> + if (oi->ip_flags & OCFS2_INODE_SYSTEM_FILE) {
> ret = -EINVAL;
> mlog_errno(ret);
> goto out;
> @@ -4182,6 +4184,26 @@ static int __ocfs2_reflink(struct dentry *old_dentry,
> goto out_unlock;
> }
>
> + if ((oi->ip_dyn_features & OCFS2_HAS_XATTR_FL) &&
> + (oi->ip_dyn_features & OCFS2_INLINE_XATTR_FL)) {
> + /*
> + * Adjust extent record count to reserve space for extended attribute.
> + * Inline data count had been adjusted in ocfs2_duplicate_inline_data().
> + */
> + struct ocfs2_inode_info *ni = OCFS2_I(new_inode);

Could you please rename it to 'new_oi'?
Other looks good to me.

Joseph
> +
> + if (!(ni->ip_dyn_features & OCFS2_INLINE_DATA_FL) &&
> + !(ocfs2_inode_is_fast_symlink(new_inode))) {
> + struct ocfs2_dinode *new_di = new_bh->b_data;
> + struct ocfs2_dinode *old_di = old_bh->b_data;
> + struct ocfs2_extent_list *el = &new_di->id2.i_list;
> + int inline_size = le16_to_cpu(old_di->i_xattr_inline_size);
> +
> + le16_add_cpu(&el->l_count, -(inline_size /
> + sizeof(struct ocfs2_extent_rec)));
> + }
> + }
> +
> ret = ocfs2_create_reflink_node(inode, old_bh,
> new_inode, new_bh, preserve);
> if (ret) {
> @@ -4189,7 +4211,7 @@ static int __ocfs2_reflink(struct dentry *old_dentry,
> goto inode_unlock;
> }
>
> - if (OCFS2_I(inode)->ip_dyn_features & OCFS2_HAS_XATTR_FL) {
> + if (oi->ip_dyn_features & OCFS2_HAS_XATTR_FL) {
> ret = ocfs2_reflink_xattrs(inode, old_bh,
> new_inode, new_bh,
> preserve);
> diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
> index 3b81213ed7b8..a9f716ec89e2 100644
> --- a/fs/ocfs2/xattr.c
> +++ b/fs/ocfs2/xattr.c
> @@ -6511,16 +6511,7 @@ static int ocfs2_reflink_xattr_inline(struct ocfs2_xattr_reflink *args)
> }
>
> new_oi = OCFS2_I(args->new_inode);
> - /*
> - * Adjust extent record count to reserve space for extended attribute.
> - * Inline data count had been adjusted in ocfs2_duplicate_inline_data().
> - */
> - if (!(new_oi->ip_dyn_features & OCFS2_INLINE_DATA_FL) &&
> - !(ocfs2_inode_is_fast_symlink(args->new_inode))) {
> - struct ocfs2_extent_list *el = &new_di->id2.i_list;
> - le16_add_cpu(&el->l_count, -(inline_size /
> - sizeof(struct ocfs2_extent_rec)));
> - }
> +
> spin_lock(&new_oi->ip_lock);
> new_oi->ip_dyn_features |= OCFS2_HAS_XATTR_FL | OCFS2_INLINE_XATTR_FL;
> new_di->i_dyn_features = cpu_to_le16(new_oi->ip_dyn_features);