diff mbox series

[v3,4/9] cachefiles: propagate errors from vfs_getxattr() to avoid infinite loop

Message ID 20240628062930.2467993-5-libaokun@huaweicloud.com (mailing list archive)
State New
Headers show
Series cachefiles: random bugfixes | expand

Commit Message

Baokun Li June 28, 2024, 6:29 a.m. UTC 
From: Baokun Li <libaokun1@huawei.com>

In cachefiles_check_volume_xattr(), the error returned by vfs_getxattr()
is not passed to ret, so it ends up returning -ESTALE, which leads to an
endless loop as follows:

cachefiles_acquire_volume
retry:
  ret = cachefiles_check_volume_xattr
    ret = -ESTALE
    xlen = vfs_getxattr // return -EIO
    // The ret is not updated when xlen < 0, so -ESTALE is returned.
    return ret
  // Supposed to jump out of the loop at this judgement.
  if (ret != -ESTALE)
      goto error_dir;
  cachefiles_bury_object
    //  EIO causes rename failure
  goto retry;

Hence propagate the error returned by vfs_getxattr() to avoid the above
issue. Do the same in cachefiles_check_auxdata().

Fixes: 32e150037dce ("fscache, cachefiles: Store the volume coherency data")
Fixes: 72b957856b0c ("cachefiles: Implement metadata/coherency data storage in xattrs")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
---
 fs/cachefiles/xattr.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

Gao Xiang June 28, 2024, 7:30 a.m. UTC | #1 
On 2024/6/28 14:29, libaokun@huaweicloud.com wrote:
> From: Baokun Li <libaokun1@huawei.com>
> 
> In cachefiles_check_volume_xattr(), the error returned by vfs_getxattr()
> is not passed to ret, so it ends up returning -ESTALE, which leads to an
> endless loop as follows:
> 
> cachefiles_acquire_volume
> retry:
>    ret = cachefiles_check_volume_xattr
>      ret = -ESTALE
>      xlen = vfs_getxattr // return -EIO
>      // The ret is not updated when xlen < 0, so -ESTALE is returned.
>      return ret
>    // Supposed to jump out of the loop at this judgement.
>    if (ret != -ESTALE)
>        goto error_dir;
>    cachefiles_bury_object
>      //  EIO causes rename failure
>    goto retry;
> 
> Hence propagate the error returned by vfs_getxattr() to avoid the above
> issue. Do the same in cachefiles_check_auxdata().
> 
> Fixes: 32e150037dce ("fscache, cachefiles: Store the volume coherency data")
> Fixes: 72b957856b0c ("cachefiles: Implement metadata/coherency data storage in xattrs")
> Signed-off-by: Baokun Li <libaokun1@huawei.com>

It looks good to me,
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>

Thanks,
Gao Xiang
diff mbox series

Patch

diff --git a/fs/cachefiles/xattr.c b/fs/cachefiles/xattr.c
index bcb6173943ee..4dd8a993c60a 100644
--- a/fs/cachefiles/xattr.c
+++ b/fs/cachefiles/xattr.c
@@ -110,9 +110,11 @@  int cachefiles_check_auxdata(struct cachefiles_object *object, struct file *file
 	if (xlen == 0)
 		xlen = vfs_getxattr(&nop_mnt_idmap, dentry, cachefiles_xattr_cache, buf, tlen);
 	if (xlen != tlen) {
-		if (xlen < 0)
+		if (xlen < 0) {
+			ret = xlen;
 			trace_cachefiles_vfs_error(object, file_inode(file), xlen,
 						   cachefiles_trace_getxattr_error);
+		}
 		if (xlen == -EIO)
 			cachefiles_io_error_obj(
 				object,
@@ -252,6 +254,7 @@  int cachefiles_check_volume_xattr(struct cachefiles_volume *volume)
 		xlen = vfs_getxattr(&nop_mnt_idmap, dentry, cachefiles_xattr_cache, buf, len);
 	if (xlen != len) {
 		if (xlen < 0) {
+			ret = xlen;
 			trace_cachefiles_vfs_error(NULL, d_inode(dentry), xlen,
 						   cachefiles_trace_getxattr_error);
 			if (xlen == -EIO)