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authorDarrick J. Wong <djwong@kernel.org>2021-03-22 09:51:51 -0700
committerDarrick J. Wong <djwong@kernel.org>2021-04-09 10:27:13 -0700
commit71bddbccab436a261a22afe5d90de269941d0fe7 (patch)
tree41c7465a6ff174435ec273ff5b51a2a6b5475581 /fs/xfs
parent7d88329e5b0fe636e63e2b1f078696bc85780442 (diff)
downloadlinux-71bddbccab436a261a22afe5d90de269941d0fe7.tar.bz2
xfs: fix scrub and remount-ro protection when running scrub
While running a new fstest that races a readonly remount with scrub running in repair mode, I observed the kernel tripping over debugging assertions in the log quiesce code that were checking that the CIL was empty. When the sysadmin runs scrub in repair mode, the scrub code allocates real transactions (with reservations) to change things, but doesn't increment the superblock writers count to block a readonly remount attempt while it is running. We don't require the userspace caller to have a writable file descriptor to run repairs, so we have to call mnt_want_write_file to obtain freeze protection and increment the writers count. It's ok to remove the call to sb_start_write for the dry-run case because commit 8321ddb2fa29 removed the behavior where scrub and fsfreeze fight over the buffer LRU. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/xfs')
-rw-r--r--fs/xfs/scrub/scrub.c31
-rw-r--r--fs/xfs/scrub/scrub.h11
-rw-r--r--fs/xfs/scrub/xfs_scrub.h4
-rw-r--r--fs/xfs/xfs_ioctl.c6
4 files changed, 35 insertions, 17 deletions
diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
index 47c68c72bcac..21ebd3f4af9f 100644
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -149,9 +149,10 @@ xchk_probe(
STATIC int
xchk_teardown(
struct xfs_scrub *sc,
- struct xfs_inode *ip_in,
int error)
{
+ struct xfs_inode *ip_in = XFS_I(file_inode(sc->file));
+
xchk_ag_free(sc, &sc->sa);
if (sc->tp) {
if (error == 0 && (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR))
@@ -168,7 +169,8 @@ xchk_teardown(
xfs_irele(sc->ip);
sc->ip = NULL;
}
- sb_end_write(sc->mp->m_super);
+ if (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)
+ mnt_drop_write_file(sc->file);
if (sc->flags & XCHK_REAPING_DISABLED)
xchk_start_reaping(sc);
if (sc->flags & XCHK_HAS_QUOTAOFFLOCK) {
@@ -456,19 +458,22 @@ static inline void xchk_postmortem(struct xfs_scrub *sc)
/* Dispatch metadata scrubbing. */
int
xfs_scrub_metadata(
- struct xfs_inode *ip,
+ struct file *file,
struct xfs_scrub_metadata *sm)
{
struct xfs_scrub sc = {
- .mp = ip->i_mount,
+ .file = file,
.sm = sm,
.sa = {
.agno = NULLAGNUMBER,
},
};
+ struct xfs_inode *ip = XFS_I(file_inode(file));
struct xfs_mount *mp = ip->i_mount;
int error = 0;
+ sc.mp = mp;
+
BUILD_BUG_ON(sizeof(meta_scrub_ops) !=
(sizeof(struct xchk_meta_ops) * XFS_SCRUB_TYPE_NR));
@@ -492,12 +497,14 @@ xfs_scrub_metadata(
sc.sick_mask = xchk_health_mask_for_scrub_type(sm->sm_type);
retry_op:
/*
- * If freeze runs concurrently with a scrub, the freeze can be delayed
- * indefinitely as we walk the filesystem and iterate over metadata
- * buffers. Freeze quiesces the log (which waits for the buffer LRU to
- * be emptied) and that won't happen while checking is running.
+ * When repairs are allowed, prevent freezing or readonly remount while
+ * scrub is running with a real transaction.
*/
- sb_start_write(mp->m_super);
+ if (sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) {
+ error = mnt_want_write_file(sc.file);
+ if (error)
+ goto out;
+ }
/* Set up for the operation. */
error = sc.ops->setup(&sc, ip);
@@ -512,7 +519,7 @@ retry_op:
* Tear down everything we hold, then set up again with
* preparation for worst-case scenarios.
*/
- error = xchk_teardown(&sc, ip, 0);
+ error = xchk_teardown(&sc, 0);
if (error)
goto out;
sc.flags |= XCHK_TRY_HARDER;
@@ -553,7 +560,7 @@ retry_op:
* get all the resources it needs; either way, we go
* back to the beginning and call the scrub function.
*/
- error = xchk_teardown(&sc, ip, 0);
+ error = xchk_teardown(&sc, 0);
if (error) {
xrep_failure(mp);
goto out;
@@ -565,7 +572,7 @@ retry_op:
out_nofix:
xchk_postmortem(&sc);
out_teardown:
- error = xchk_teardown(&sc, ip, error);
+ error = xchk_teardown(&sc, error);
out:
trace_xchk_done(ip, sm, error);
if (error == -EFSCORRUPTED || error == -EFSBADCRC) {
diff --git a/fs/xfs/scrub/scrub.h b/fs/xfs/scrub/scrub.h
index ad1ceb44a628..e776ab4ad322 100644
--- a/fs/xfs/scrub/scrub.h
+++ b/fs/xfs/scrub/scrub.h
@@ -59,7 +59,18 @@ struct xfs_scrub {
struct xfs_scrub_metadata *sm;
const struct xchk_meta_ops *ops;
struct xfs_trans *tp;
+
+ /* File that scrub was called with. */
+ struct file *file;
+
+ /*
+ * File that is undergoing the scrub operation. This can differ from
+ * the file that scrub was called with if we're checking file-based fs
+ * metadata (e.g. rt bitmaps) or if we're doing a scrub-by-handle for
+ * something that can't be opened directly (e.g. symlinks).
+ */
struct xfs_inode *ip;
+
void *buf;
uint ilock_flags;
diff --git a/fs/xfs/scrub/xfs_scrub.h b/fs/xfs/scrub/xfs_scrub.h
index 2897ba3a17e6..2ceae614ade8 100644
--- a/fs/xfs/scrub/xfs_scrub.h
+++ b/fs/xfs/scrub/xfs_scrub.h
@@ -7,9 +7,9 @@
#define __XFS_SCRUB_H__
#ifndef CONFIG_XFS_ONLINE_SCRUB
-# define xfs_scrub_metadata(ip, sm) (-ENOTTY)
+# define xfs_scrub_metadata(file, sm) (-ENOTTY)
#else
-int xfs_scrub_metadata(struct xfs_inode *ip, struct xfs_scrub_metadata *sm);
+int xfs_scrub_metadata(struct file *file, struct xfs_scrub_metadata *sm);
#endif /* CONFIG_XFS_ONLINE_SCRUB */
#endif /* __XFS_SCRUB_H__ */
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index e6e4e248cd86..708b77341a70 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1847,7 +1847,7 @@ out_free:
STATIC int
xfs_ioc_scrub_metadata(
- struct xfs_inode *ip,
+ struct file *file,
void __user *arg)
{
struct xfs_scrub_metadata scrub;
@@ -1859,7 +1859,7 @@ xfs_ioc_scrub_metadata(
if (copy_from_user(&scrub, arg, sizeof(scrub)))
return -EFAULT;
- error = xfs_scrub_metadata(ip, &scrub);
+ error = xfs_scrub_metadata(file, &scrub);
if (error)
return error;
@@ -2158,7 +2158,7 @@ xfs_file_ioctl(
return xfs_ioc_getfsmap(ip, arg);
case XFS_IOC_SCRUB_METADATA:
- return xfs_ioc_scrub_metadata(ip, arg);
+ return xfs_ioc_scrub_metadata(filp, arg);
case XFS_IOC_FD_TO_HANDLE:
case XFS_IOC_PATH_TO_HANDLE: