| Message ID | 20200218200103.12574-1-lsahlber@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | cifs: don't leak -EAGAIN for stat() during reconnect | expand |
merged into cifs-2.6.git for-next On Tue, Feb 18, 2020 at 2:07 PM Ronnie Sahlberg <lsahlber@redhat.com> wrote: > > If from cifs_revalidate_dentry_attr() the SMB2/QUERY_INFO call fails with an > error, such as STATUS_SESSION_EXPIRED, causing the session to be reconnected > it is possible we will leak -EAGAIN back to the application even for > system calls such as stat() where this is not a valid error. > > Fix this by re-trying the operation from within cifs_revalidate_dentry_attr() > if cifs_get_inode_info*() returns -EAGAIN. > > This fixes stat() and possibly also other system calls that uses > cifs_revalidate_dentry*(). > > Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> > --- > fs/cifs/inode.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c > index b5e6635c578e..1212ace05258 100644 > --- a/fs/cifs/inode.c > +++ b/fs/cifs/inode.c > @@ -2073,6 +2073,7 @@ int cifs_revalidate_dentry_attr(struct dentry *dentry) > struct inode *inode = d_inode(dentry); > struct super_block *sb = dentry->d_sb; > char *full_path = NULL; > + int count = 0; > > if (inode == NULL) > return -ENOENT; > @@ -2094,15 +2095,18 @@ int cifs_revalidate_dentry_attr(struct dentry *dentry) > full_path, inode, inode->i_count.counter, > dentry, cifs_get_time(dentry), jiffies); > > +again: > if (cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext) > rc = cifs_get_inode_info_unix(&inode, full_path, sb, xid); > else > rc = cifs_get_inode_info(&inode, full_path, NULL, sb, > xid, NULL); > - > + if (is_retryable_error(rc) && count++ < 10) > + goto again; > out: > kfree(full_path); > free_xid(xid); > + > return rc; > } > > -- > 2.13.6 >
вт, 18 февр. 2020 г. в 15:27, Steve French <smfrench@gmail.com>: > > merged into cifs-2.6.git for-next > > On Tue, Feb 18, 2020 at 2:07 PM Ronnie Sahlberg <lsahlber@redhat.com> wrote: > > > > If from cifs_revalidate_dentry_attr() the SMB2/QUERY_INFO call fails with an > > error, such as STATUS_SESSION_EXPIRED, causing the session to be reconnected > > it is possible we will leak -EAGAIN back to the application even for > > system calls such as stat() where this is not a valid error. > > > > Fix this by re-trying the operation from within cifs_revalidate_dentry_attr() > > if cifs_get_inode_info*() returns -EAGAIN. > > > > This fixes stat() and possibly also other system calls that uses > > cifs_revalidate_dentry*(). > > > > Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> > > --- > > fs/cifs/inode.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c > > index b5e6635c578e..1212ace05258 100644 > > --- a/fs/cifs/inode.c > > +++ b/fs/cifs/inode.c > > @@ -2073,6 +2073,7 @@ int cifs_revalidate_dentry_attr(struct dentry *dentry) > > struct inode *inode = d_inode(dentry); > > struct super_block *sb = dentry->d_sb; > > char *full_path = NULL; > > + int count = 0; > > > > if (inode == NULL) > > return -ENOENT; > > @@ -2094,15 +2095,18 @@ int cifs_revalidate_dentry_attr(struct dentry *dentry) > > full_path, inode, inode->i_count.counter, > > dentry, cifs_get_time(dentry), jiffies); > > > > +again: > > if (cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext) > > rc = cifs_get_inode_info_unix(&inode, full_path, sb, xid); > > else > > rc = cifs_get_inode_info(&inode, full_path, NULL, sb, > > xid, NULL); > > - > > + if (is_retryable_error(rc) && count++ < 10) > > + goto again; If there is interrupt error, you will end up doing 10 attempts with the same outcome - interrupt error. Such errors should be returned to the upper layers to be handled correctly (restart of a system call or return of EINTR error to the user space). Please revert to your original version that handles EAGAIN only. -- Best regards, Pavel Shilovsky > > out: > > kfree(full_path); > > free_xid(xid); > > + > > return rc; > > } > > > > -- > > 2.13.6 > > > > > -- > Thanks, > > Steve
updated Ronnie's patch and remerged to cifs-2.6.git for-next Let me know if any objections On Mon, Feb 24, 2020 at 1:36 PM Pavel Shilovsky <piastryyy@gmail.com> wrote: > > вт, 18 февр. 2020 г. в 15:27, Steve French <smfrench@gmail.com>: > > > > merged into cifs-2.6.git for-next > > > > On Tue, Feb 18, 2020 at 2:07 PM Ronnie Sahlberg <lsahlber@redhat.com> wrote: > > > > > > If from cifs_revalidate_dentry_attr() the SMB2/QUERY_INFO call fails with an > > > error, such as STATUS_SESSION_EXPIRED, causing the session to be reconnected > > > it is possible we will leak -EAGAIN back to the application even for > > > system calls such as stat() where this is not a valid error. > > > > > > Fix this by re-trying the operation from within cifs_revalidate_dentry_attr() > > > if cifs_get_inode_info*() returns -EAGAIN. > > > > > > This fixes stat() and possibly also other system calls that uses > > > cifs_revalidate_dentry*(). > > > > > > Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> > > > --- > > > fs/cifs/inode.c | 6 +++++- > > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > > > diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c > > > index b5e6635c578e..1212ace05258 100644 > > > --- a/fs/cifs/inode.c > > > +++ b/fs/cifs/inode.c > > > @@ -2073,6 +2073,7 @@ int cifs_revalidate_dentry_attr(struct dentry *dentry) > > > struct inode *inode = d_inode(dentry); > > > struct super_block *sb = dentry->d_sb; > > > char *full_path = NULL; > > > + int count = 0; > > > > > > if (inode == NULL) > > > return -ENOENT; > > > @@ -2094,15 +2095,18 @@ int cifs_revalidate_dentry_attr(struct dentry *dentry) > > > full_path, inode, inode->i_count.counter, > > > dentry, cifs_get_time(dentry), jiffies); > > > > > > +again: > > > if (cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext) > > > rc = cifs_get_inode_info_unix(&inode, full_path, sb, xid); > > > else > > > rc = cifs_get_inode_info(&inode, full_path, NULL, sb, > > > xid, NULL); > > > - > > > + if (is_retryable_error(rc) && count++ < 10) > > > + goto again; > > If there is interrupt error, you will end up doing 10 attempts with > the same outcome - interrupt error. Such errors should be returned to > the upper layers to be handled correctly (restart of a system call or > return of EINTR error to the user space). > > Please revert to your original version that handles EAGAIN only. > > -- > Best regards, > Pavel Shilovsky > > > > out: > > > kfree(full_path); > > > free_xid(xid); > > > + > > > return rc; > > > } > > > > > > -- > > > 2.13.6 > > > > > > > > > -- > > Thanks, > > > > Steve
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c index b5e6635c578e..1212ace05258 100644 --- a/fs/cifs/inode.c +++ b/fs/cifs/inode.c @@ -2073,6 +2073,7 @@ int cifs_revalidate_dentry_attr(struct dentry *dentry) struct inode *inode = d_inode(dentry); struct super_block *sb = dentry->d_sb; char *full_path = NULL; + int count = 0; if (inode == NULL) return -ENOENT; @@ -2094,15 +2095,18 @@ int cifs_revalidate_dentry_attr(struct dentry *dentry) full_path, inode, inode->i_count.counter, dentry, cifs_get_time(dentry), jiffies); +again: if (cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext) rc = cifs_get_inode_info_unix(&inode, full_path, sb, xid); else rc = cifs_get_inode_info(&inode, full_path, NULL, sb, xid, NULL); - + if (is_retryable_error(rc) && count++ < 10) + goto again; out: kfree(full_path); free_xid(xid); + return rc; }
If from cifs_revalidate_dentry_attr() the SMB2/QUERY_INFO call fails with an error, such as STATUS_SESSION_EXPIRED, causing the session to be reconnected it is possible we will leak -EAGAIN back to the application even for system calls such as stat() where this is not a valid error. Fix this by re-trying the operation from within cifs_revalidate_dentry_attr() if cifs_get_inode_info*() returns -EAGAIN. This fixes stat() and possibly also other system calls that uses cifs_revalidate_dentry*(). Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> --- fs/cifs/inode.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)