* [PATCH] ceph: fix error handling in ceph_atomic_open and ceph_lookup
@ 2021-06-03 12:38 Jeff Layton
2021-06-21 19:20 ` Ilya Dryomov
2021-06-21 23:57 ` [PATCH v2] " Jeff Layton
0 siblings, 2 replies; 6+ messages in thread
From: Jeff Layton @ 2021-06-03 12:38 UTC (permalink / raw)
To: ceph-devel, idryomov
Commit aa60cfc3f7ee broke the error handling in these functions such
that they don't handle non-ENOENT errors from ceph_mdsc_do_request
properly.
Move the checking of -ENOENT out of ceph_handle_snapdir and into the
callers, and if we get a different error, return it immediately.
Fixes: aa60cfc3f7ee ("ceph: don't use d_add in ceph_handle_snapdir")
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
fs/ceph/dir.c | 17 ++++++-----------
fs/ceph/file.c | 6 +++---
fs/ceph/super.h | 2 +-
3 files changed, 10 insertions(+), 15 deletions(-)
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 5624fae7a603..ac431246e0c9 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -668,14 +668,13 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
* Handle lookups for the hidden .snap directory.
*/
struct dentry *ceph_handle_snapdir(struct ceph_mds_request *req,
- struct dentry *dentry, int err)
+ struct dentry *dentry)
{
struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
struct inode *parent = d_inode(dentry->d_parent); /* we hold i_mutex */
/* .snap dir? */
- if (err == -ENOENT &&
- ceph_snap(parent) == CEPH_NOSNAP &&
+ if (ceph_snap(parent) == CEPH_NOSNAP &&
strcmp(dentry->d_name.name, fsc->mount_options->snapdir_name) == 0) {
struct dentry *res;
struct inode *inode = ceph_get_snapdir(parent);
@@ -742,7 +741,6 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
struct ceph_mds_request *req;
- struct dentry *res;
int op;
int mask;
int err;
@@ -793,13 +791,10 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
req->r_parent = dir;
set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
err = ceph_mdsc_do_request(mdsc, NULL, req);
- res = ceph_handle_snapdir(req, dentry, err);
- if (IS_ERR(res)) {
- err = PTR_ERR(res);
- } else {
- dentry = res;
- err = 0;
- }
+ if (err == -ENOENT)
+ dentry = ceph_handle_snapdir(req, dentry);
+ if (IS_ERR(dentry))
+ err = PTR_ERR(dentry);
dentry = ceph_finish_lookup(req, dentry, err);
ceph_mdsc_put_request(req); /* will dput(dentry) */
dout("lookup result=%p\n", dentry);
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 7aa20d50a231..a01ad342a91d 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -739,14 +739,14 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
err = ceph_mdsc_do_request(mdsc,
(flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
req);
- dentry = ceph_handle_snapdir(req, dentry, err);
+ if (err == -ENOENT)
+ dentry = ceph_handle_snapdir(req, dentry);
if (IS_ERR(dentry)) {
err = PTR_ERR(dentry);
goto out_req;
}
- err = 0;
- if ((flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
+ if (!err && (flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
err = ceph_handle_notrace_create(dir, dentry);
if (d_in_lookup(dentry)) {
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 12d30153e4ca..31f0be9120dd 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1217,7 +1217,7 @@ extern const struct dentry_operations ceph_dentry_ops;
extern loff_t ceph_make_fpos(unsigned high, unsigned off, bool hash_order);
extern int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry);
extern struct dentry *ceph_handle_snapdir(struct ceph_mds_request *req,
- struct dentry *dentry, int err);
+ struct dentry *dentry);
extern struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
struct dentry *dentry, int err);
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] ceph: fix error handling in ceph_atomic_open and ceph_lookup
2021-06-03 12:38 [PATCH] ceph: fix error handling in ceph_atomic_open and ceph_lookup Jeff Layton
@ 2021-06-21 19:20 ` Ilya Dryomov
2021-06-21 23:49 ` Jeff Layton
2021-06-21 23:57 ` [PATCH v2] " Jeff Layton
1 sibling, 1 reply; 6+ messages in thread
From: Ilya Dryomov @ 2021-06-21 19:20 UTC (permalink / raw)
To: Jeff Layton; +Cc: Ceph Development
On Thu, Jun 3, 2021 at 2:38 PM Jeff Layton <jlayton@kernel.org> wrote:
>
> Commit aa60cfc3f7ee broke the error handling in these functions such
> that they don't handle non-ENOENT errors from ceph_mdsc_do_request
> properly.
>
> Move the checking of -ENOENT out of ceph_handle_snapdir and into the
> callers, and if we get a different error, return it immediately.
>
> Fixes: aa60cfc3f7ee ("ceph: don't use d_add in ceph_handle_snapdir")
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
> fs/ceph/dir.c | 17 ++++++-----------
> fs/ceph/file.c | 6 +++---
> fs/ceph/super.h | 2 +-
> 3 files changed, 10 insertions(+), 15 deletions(-)
>
> diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
> index 5624fae7a603..ac431246e0c9 100644
> --- a/fs/ceph/dir.c
> +++ b/fs/ceph/dir.c
> @@ -668,14 +668,13 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
> * Handle lookups for the hidden .snap directory.
> */
> struct dentry *ceph_handle_snapdir(struct ceph_mds_request *req,
> - struct dentry *dentry, int err)
> + struct dentry *dentry)
> {
> struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
> struct inode *parent = d_inode(dentry->d_parent); /* we hold i_mutex */
>
> /* .snap dir? */
> - if (err == -ENOENT &&
> - ceph_snap(parent) == CEPH_NOSNAP &&
> + if (ceph_snap(parent) == CEPH_NOSNAP &&
> strcmp(dentry->d_name.name, fsc->mount_options->snapdir_name) == 0) {
> struct dentry *res;
> struct inode *inode = ceph_get_snapdir(parent);
> @@ -742,7 +741,6 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
> struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
> struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
> struct ceph_mds_request *req;
> - struct dentry *res;
> int op;
> int mask;
> int err;
> @@ -793,13 +791,10 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
> req->r_parent = dir;
> set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
> err = ceph_mdsc_do_request(mdsc, NULL, req);
> - res = ceph_handle_snapdir(req, dentry, err);
> - if (IS_ERR(res)) {
> - err = PTR_ERR(res);
> - } else {
> - dentry = res;
> - err = 0;
> - }
> + if (err == -ENOENT)
> + dentry = ceph_handle_snapdir(req, dentry);
> + if (IS_ERR(dentry))
> + err = PTR_ERR(dentry);
> dentry = ceph_finish_lookup(req, dentry, err);
> ceph_mdsc_put_request(req); /* will dput(dentry) */
> dout("lookup result=%p\n", dentry);
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 7aa20d50a231..a01ad342a91d 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -739,14 +739,14 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
> err = ceph_mdsc_do_request(mdsc,
> (flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
> req);
> - dentry = ceph_handle_snapdir(req, dentry, err);
> + if (err == -ENOENT)
> + dentry = ceph_handle_snapdir(req, dentry);
> if (IS_ERR(dentry)) {
> err = PTR_ERR(dentry);
> goto out_req;
> }
Hi Jeff,
This doesn't seem right to me. Looking at 5.12, ENOENT from
ceph_mdsc_do_request() could be resolved by ceph_handle_snapdir()
meaning that ceph_handle_notrace_create() could be called and
ceph_finish_lookup() could be passed err == 0.
With this patch err would remain ENOENT, resulting in skipping
the potential ceph_handle_notrace_create() call and passing that
ENOENT to ceph_finish_lookup().
Thanks,
Ilya
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] ceph: fix error handling in ceph_atomic_open and ceph_lookup
2021-06-21 19:20 ` Ilya Dryomov
@ 2021-06-21 23:49 ` Jeff Layton
0 siblings, 0 replies; 6+ messages in thread
From: Jeff Layton @ 2021-06-21 23:49 UTC (permalink / raw)
To: Ilya Dryomov; +Cc: Ceph Development
On Mon, 2021-06-21 at 21:20 +0200, Ilya Dryomov wrote:
> On Thu, Jun 3, 2021 at 2:38 PM Jeff Layton <jlayton@kernel.org> wrote:
> >
> > Commit aa60cfc3f7ee broke the error handling in these functions such
> > that they don't handle non-ENOENT errors from ceph_mdsc_do_request
> > properly.
> >
> > Move the checking of -ENOENT out of ceph_handle_snapdir and into the
> > callers, and if we get a different error, return it immediately.
> >
> > Fixes: aa60cfc3f7ee ("ceph: don't use d_add in ceph_handle_snapdir")
> > Signed-off-by: Jeff Layton <jlayton@kernel.org>
> > ---
> > fs/ceph/dir.c | 17 ++++++-----------
> > fs/ceph/file.c | 6 +++---
> > fs/ceph/super.h | 2 +-
> > 3 files changed, 10 insertions(+), 15 deletions(-)
> >
> > diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
> > index 5624fae7a603..ac431246e0c9 100644
> > --- a/fs/ceph/dir.c
> > +++ b/fs/ceph/dir.c
> > @@ -668,14 +668,13 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
> > * Handle lookups for the hidden .snap directory.
> > */
> > struct dentry *ceph_handle_snapdir(struct ceph_mds_request *req,
> > - struct dentry *dentry, int err)
> > + struct dentry *dentry)
> > {
> > struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
> > struct inode *parent = d_inode(dentry->d_parent); /* we hold i_mutex */
> >
> > /* .snap dir? */
> > - if (err == -ENOENT &&
> > - ceph_snap(parent) == CEPH_NOSNAP &&
> > + if (ceph_snap(parent) == CEPH_NOSNAP &&
> > strcmp(dentry->d_name.name, fsc->mount_options->snapdir_name) == 0) {
> > struct dentry *res;
> > struct inode *inode = ceph_get_snapdir(parent);
> > @@ -742,7 +741,6 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
> > struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
> > struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
> > struct ceph_mds_request *req;
> > - struct dentry *res;
> > int op;
> > int mask;
> > int err;
> > @@ -793,13 +791,10 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
> > req->r_parent = dir;
> > set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
> > err = ceph_mdsc_do_request(mdsc, NULL, req);
> > - res = ceph_handle_snapdir(req, dentry, err);
> > - if (IS_ERR(res)) {
> > - err = PTR_ERR(res);
> > - } else {
> > - dentry = res;
> > - err = 0;
> > - }
> > + if (err == -ENOENT)
> > + dentry = ceph_handle_snapdir(req, dentry);
> > + if (IS_ERR(dentry))
> > + err = PTR_ERR(dentry);
> > dentry = ceph_finish_lookup(req, dentry, err);
> > ceph_mdsc_put_request(req); /* will dput(dentry) */
> > dout("lookup result=%p\n", dentry);
> > diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> > index 7aa20d50a231..a01ad342a91d 100644
> > --- a/fs/ceph/file.c
> > +++ b/fs/ceph/file.c
> > @@ -739,14 +739,14 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
> > err = ceph_mdsc_do_request(mdsc,
> > (flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
> > req);
> > - dentry = ceph_handle_snapdir(req, dentry, err);
> > + if (err == -ENOENT)
> > + dentry = ceph_handle_snapdir(req, dentry);
> > if (IS_ERR(dentry)) {
> > err = PTR_ERR(dentry);
> > goto out_req;
> > }
>
> Hi Jeff,
>
> This doesn't seem right to me. Looking at 5.12, ENOENT from
> ceph_mdsc_do_request() could be resolved by ceph_handle_snapdir()
> meaning that ceph_handle_notrace_create() could be called and
> ceph_finish_lookup() could be passed err == 0.
>
> With this patch err would remain ENOENT, resulting in skipping
> the potential ceph_handle_notrace_create() call and passing that
> ENOENT to ceph_finish_lookup().
>
Well spotted! I have a v2 version that I'm running through xfstests now.
I'll send it along in a bit.
Thanks!
--
Jeff Layton <jlayton@kernel.org>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2] ceph: fix error handling in ceph_atomic_open and ceph_lookup
2021-06-03 12:38 [PATCH] ceph: fix error handling in ceph_atomic_open and ceph_lookup Jeff Layton
2021-06-21 19:20 ` Ilya Dryomov
@ 2021-06-21 23:57 ` Jeff Layton
2021-06-22 12:09 ` Ilya Dryomov
1 sibling, 1 reply; 6+ messages in thread
From: Jeff Layton @ 2021-06-21 23:57 UTC (permalink / raw)
To: ceph-devel; +Cc: idryomov
Commit aa60cfc3f7ee broke the error handling in these functions such
that they don't handle non-ENOENT errors from ceph_mdsc_do_request
properly.
Move the checking of -ENOENT out of ceph_handle_snapdir and into the
callers, and if we get a different error, return it immediately.
Fixes: aa60cfc3f7ee ("ceph: don't use d_add in ceph_handle_snapdir")
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
fs/ceph/dir.c | 22 ++++++++++++----------
fs/ceph/file.c | 14 ++++++++------
fs/ceph/super.h | 2 +-
3 files changed, 21 insertions(+), 17 deletions(-)
This one fixes the bug that Ilya spotted in ceph_atomic_open. Also,
there is no need to test IS_ERR(dentry) unless we called
ceph_handle_snapdir. Finally, it's probably best not to pass
ceph_finish_lookup an ERR_PTR as a dentry. Reinstate the res pointer and
only reset the dentry pointer if it's valid.
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 5624fae7a603..e78da771ec96 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -668,14 +668,13 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
* Handle lookups for the hidden .snap directory.
*/
struct dentry *ceph_handle_snapdir(struct ceph_mds_request *req,
- struct dentry *dentry, int err)
+ struct dentry *dentry)
{
struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
struct inode *parent = d_inode(dentry->d_parent); /* we hold i_mutex */
/* .snap dir? */
- if (err == -ENOENT &&
- ceph_snap(parent) == CEPH_NOSNAP &&
+ if (ceph_snap(parent) == CEPH_NOSNAP &&
strcmp(dentry->d_name.name, fsc->mount_options->snapdir_name) == 0) {
struct dentry *res;
struct inode *inode = ceph_get_snapdir(parent);
@@ -742,7 +741,6 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
struct ceph_mds_request *req;
- struct dentry *res;
int op;
int mask;
int err;
@@ -793,12 +791,16 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
req->r_parent = dir;
set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
err = ceph_mdsc_do_request(mdsc, NULL, req);
- res = ceph_handle_snapdir(req, dentry, err);
- if (IS_ERR(res)) {
- err = PTR_ERR(res);
- } else {
- dentry = res;
- err = 0;
+ if (err == -ENOENT) {
+ struct dentry *res;
+
+ res = ceph_handle_snapdir(req, dentry);
+ if (IS_ERR(res)) {
+ err = PTR_ERR(res);
+ } else {
+ dentry = res;
+ err = 0;
+ }
}
dentry = ceph_finish_lookup(req, dentry, err);
ceph_mdsc_put_request(req); /* will dput(dentry) */
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 7aa20d50a231..7c08f864694f 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -739,14 +739,16 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
err = ceph_mdsc_do_request(mdsc,
(flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
req);
- dentry = ceph_handle_snapdir(req, dentry, err);
- if (IS_ERR(dentry)) {
- err = PTR_ERR(dentry);
- goto out_req;
+ if (err == -ENOENT) {
+ dentry = ceph_handle_snapdir(req, dentry);
+ if (IS_ERR(dentry)) {
+ err = PTR_ERR(dentry);
+ goto out_req;
+ }
+ err = 0;
}
- err = 0;
- if ((flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
+ if (!err && (flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
err = ceph_handle_notrace_create(dir, dentry);
if (d_in_lookup(dentry)) {
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 12d30153e4ca..31f0be9120dd 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1217,7 +1217,7 @@ extern const struct dentry_operations ceph_dentry_ops;
extern loff_t ceph_make_fpos(unsigned high, unsigned off, bool hash_order);
extern int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry);
extern struct dentry *ceph_handle_snapdir(struct ceph_mds_request *req,
- struct dentry *dentry, int err);
+ struct dentry *dentry);
extern struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
struct dentry *dentry, int err);
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH v2] ceph: fix error handling in ceph_atomic_open and ceph_lookup
2021-06-21 23:57 ` [PATCH v2] " Jeff Layton
@ 2021-06-22 12:09 ` Ilya Dryomov
2021-06-22 12:24 ` Jeff Layton
0 siblings, 1 reply; 6+ messages in thread
From: Ilya Dryomov @ 2021-06-22 12:09 UTC (permalink / raw)
To: Jeff Layton; +Cc: Ceph Development
On Tue, Jun 22, 2021 at 1:57 AM Jeff Layton <jlayton@kernel.org> wrote:
>
> Commit aa60cfc3f7ee broke the error handling in these functions such
> that they don't handle non-ENOENT errors from ceph_mdsc_do_request
> properly.
>
> Move the checking of -ENOENT out of ceph_handle_snapdir and into the
> callers, and if we get a different error, return it immediately.
>
> Fixes: aa60cfc3f7ee ("ceph: don't use d_add in ceph_handle_snapdir")
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
> fs/ceph/dir.c | 22 ++++++++++++----------
> fs/ceph/file.c | 14 ++++++++------
> fs/ceph/super.h | 2 +-
> 3 files changed, 21 insertions(+), 17 deletions(-)
>
> This one fixes the bug that Ilya spotted in ceph_atomic_open. Also,
> there is no need to test IS_ERR(dentry) unless we called
> ceph_handle_snapdir. Finally, it's probably best not to pass
> ceph_finish_lookup an ERR_PTR as a dentry. Reinstate the res pointer and
> only reset the dentry pointer if it's valid.
>
> diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
> index 5624fae7a603..e78da771ec96 100644
> --- a/fs/ceph/dir.c
> +++ b/fs/ceph/dir.c
> @@ -668,14 +668,13 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
> * Handle lookups for the hidden .snap directory.
> */
> struct dentry *ceph_handle_snapdir(struct ceph_mds_request *req,
> - struct dentry *dentry, int err)
> + struct dentry *dentry)
> {
> struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
> struct inode *parent = d_inode(dentry->d_parent); /* we hold i_mutex */
>
> /* .snap dir? */
> - if (err == -ENOENT &&
> - ceph_snap(parent) == CEPH_NOSNAP &&
> + if (ceph_snap(parent) == CEPH_NOSNAP &&
> strcmp(dentry->d_name.name, fsc->mount_options->snapdir_name) == 0) {
> struct dentry *res;
> struct inode *inode = ceph_get_snapdir(parent);
> @@ -742,7 +741,6 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
> struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
> struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
> struct ceph_mds_request *req;
> - struct dentry *res;
> int op;
> int mask;
> int err;
> @@ -793,12 +791,16 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
> req->r_parent = dir;
> set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
> err = ceph_mdsc_do_request(mdsc, NULL, req);
> - res = ceph_handle_snapdir(req, dentry, err);
> - if (IS_ERR(res)) {
> - err = PTR_ERR(res);
> - } else {
> - dentry = res;
> - err = 0;
> + if (err == -ENOENT) {
> + struct dentry *res;
> +
> + res = ceph_handle_snapdir(req, dentry);
Stray space here, fixed in the branch.
> + if (IS_ERR(res)) {
> + err = PTR_ERR(res);
> + } else {
> + dentry = res;
> + err = 0;
> + }
> }
> dentry = ceph_finish_lookup(req, dentry, err);
> ceph_mdsc_put_request(req); /* will dput(dentry) */
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 7aa20d50a231..7c08f864694f 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -739,14 +739,16 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
> err = ceph_mdsc_do_request(mdsc,
> (flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
> req);
> - dentry = ceph_handle_snapdir(req, dentry, err);
> - if (IS_ERR(dentry)) {
> - err = PTR_ERR(dentry);
> - goto out_req;
> + if (err == -ENOENT) {
> + dentry = ceph_handle_snapdir(req, dentry);
> + if (IS_ERR(dentry)) {
> + err = PTR_ERR(dentry);
> + goto out_req;
> + }
> + err = 0;
> }
> - err = 0;
>
> - if ((flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
> + if (!err && (flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
> err = ceph_handle_notrace_create(dir, dentry);
>
> if (d_in_lookup(dentry)) {
I must admit that I don't understand the code that follows. For
example, if ceph_handle_notrace_create() returns ENOENT, is it supposed
to be resolved by ceph_finish_lookup()? Because if it gets resolved,
err is not reset and we still jump to out_req, possibly leaving some
dentry references behind. It appears to be an older bug though.
This fix for dealing with ceph_mdsc_do_request() errors seems correct,
but I really think this code needs massaging to disentangle handling of
special cases from actual errors.
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Thanks,
Ilya
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] ceph: fix error handling in ceph_atomic_open and ceph_lookup
2021-06-22 12:09 ` Ilya Dryomov
@ 2021-06-22 12:24 ` Jeff Layton
0 siblings, 0 replies; 6+ messages in thread
From: Jeff Layton @ 2021-06-22 12:24 UTC (permalink / raw)
To: Ilya Dryomov; +Cc: Ceph Development
On Tue, 2021-06-22 at 14:09 +0200, Ilya Dryomov wrote:
> On Tue, Jun 22, 2021 at 1:57 AM Jeff Layton <jlayton@kernel.org> wrote:
> >
> > Commit aa60cfc3f7ee broke the error handling in these functions such
> > that they don't handle non-ENOENT errors from ceph_mdsc_do_request
> > properly.
> >
> > Move the checking of -ENOENT out of ceph_handle_snapdir and into the
> > callers, and if we get a different error, return it immediately.
> >
> > Fixes: aa60cfc3f7ee ("ceph: don't use d_add in ceph_handle_snapdir")
> > Signed-off-by: Jeff Layton <jlayton@kernel.org>
> > ---
> > fs/ceph/dir.c | 22 ++++++++++++----------
> > fs/ceph/file.c | 14 ++++++++------
> > fs/ceph/super.h | 2 +-
> > 3 files changed, 21 insertions(+), 17 deletions(-)
> >
> > This one fixes the bug that Ilya spotted in ceph_atomic_open. Also,
> > there is no need to test IS_ERR(dentry) unless we called
> > ceph_handle_snapdir. Finally, it's probably best not to pass
> > ceph_finish_lookup an ERR_PTR as a dentry. Reinstate the res pointer and
> > only reset the dentry pointer if it's valid.
> >
> > diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
> > index 5624fae7a603..e78da771ec96 100644
> > --- a/fs/ceph/dir.c
> > +++ b/fs/ceph/dir.c
> > @@ -668,14 +668,13 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
> > * Handle lookups for the hidden .snap directory.
> > */
> > struct dentry *ceph_handle_snapdir(struct ceph_mds_request *req,
> > - struct dentry *dentry, int err)
> > + struct dentry *dentry)
> > {
> > struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
> > struct inode *parent = d_inode(dentry->d_parent); /* we hold i_mutex */
> >
> > /* .snap dir? */
> > - if (err == -ENOENT &&
> > - ceph_snap(parent) == CEPH_NOSNAP &&
> > + if (ceph_snap(parent) == CEPH_NOSNAP &&
> > strcmp(dentry->d_name.name, fsc->mount_options->snapdir_name) == 0) {
> > struct dentry *res;
> > struct inode *inode = ceph_get_snapdir(parent);
> > @@ -742,7 +741,6 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
> > struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
> > struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
> > struct ceph_mds_request *req;
> > - struct dentry *res;
> > int op;
> > int mask;
> > int err;
> > @@ -793,12 +791,16 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
> > req->r_parent = dir;
> > set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
> > err = ceph_mdsc_do_request(mdsc, NULL, req);
> > - res = ceph_handle_snapdir(req, dentry, err);
> > - if (IS_ERR(res)) {
> > - err = PTR_ERR(res);
> > - } else {
> > - dentry = res;
> > - err = 0;
> > + if (err == -ENOENT) {
> > + struct dentry *res;
> > +
> > + res = ceph_handle_snapdir(req, dentry);
>
> Stray space here, fixed in the branch.
>
Thanks!
> > + if (IS_ERR(res)) {
> > + err = PTR_ERR(res);
> > + } else {
> > + dentry = res;
> > + err = 0;
> > + }
> > }
> > dentry = ceph_finish_lookup(req, dentry, err);
> > ceph_mdsc_put_request(req); /* will dput(dentry) */
> > diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> > index 7aa20d50a231..7c08f864694f 100644
> > --- a/fs/ceph/file.c
> > +++ b/fs/ceph/file.c
> > @@ -739,14 +739,16 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
> > err = ceph_mdsc_do_request(mdsc,
> > (flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
> > req);
> > - dentry = ceph_handle_snapdir(req, dentry, err);
> > - if (IS_ERR(dentry)) {
> > - err = PTR_ERR(dentry);
> > - goto out_req;
> > + if (err == -ENOENT) {
> > + dentry = ceph_handle_snapdir(req, dentry);
> > + if (IS_ERR(dentry)) {
> > + err = PTR_ERR(dentry);
> > + goto out_req;
> > + }
> > + err = 0;
> > }
> > - err = 0;
> >
> > - if ((flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
> > + if (!err && (flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
> > err = ceph_handle_notrace_create(dir, dentry);
> >
> > if (d_in_lookup(dentry)) {
>
> I must admit that I don't understand the code that follows. For
> example, if ceph_handle_notrace_create() returns ENOENT, is it supposed
> to be resolved by ceph_finish_lookup()? Because if it gets resolved,
> err is not reset and we still jump to out_req, possibly leaving some
> dentry references behind. It appears to be an older bug though.
>
Yes. A lot of this code is unclear.
> This fix for dealing with ceph_mdsc_do_request() errors seems correct,
> but I really think this code needs massaging to disentangle handling of
> special cases from actual errors.
>
> Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
>
Thanks and I agree. This code really is a giant hairball. I really hate
the way it weaves "err" through several functions and lets them deal
with it. That alone makes this so very difficult to follow.
I intend to follow up with some more cleanup in this area, but I haven't
had the time to spend on it yet. In the meantime, if anyone else wants
to submit patches to do this cleanup, I'm happy to review them...
--
Jeff Layton <jlayton@kernel.org>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-06-22 12:24 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2021-06-03 12:38 [PATCH] ceph: fix error handling in ceph_atomic_open and ceph_lookup Jeff Layton
2021-06-21 19:20 ` Ilya Dryomov
2021-06-21 23:49 ` Jeff Layton
2021-06-21 23:57 ` [PATCH v2] " Jeff Layton
2021-06-22 12:09 ` Ilya Dryomov
2021-06-22 12:24 ` Jeff Layton
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