When the fs is mounted with active balloon someone will have to inflate/blow off one. To make it possible there will be a special ioctl for obtaining the fd.
Not very elegant solution maybe, but it's OK for PVC containers. +++ ext4: fix file allocation check in ext4_open_balloon Function alloc_file() doesn't return NULL (unlike in 2.6.32-x). It returns error pointer. File structure allocation may fail before file->f_ep_links is initialized, which may lead to crash in eventpoll_release_file(). https://jira.sw.ru/browse/PSBM-41222 mFixes: 9cea7449aa589f325fff378e7256a3c2fc8f048d "ext4: Provide a balloon nipple for management" Signed-off-by: Stanislav Kinsburskiy <skinsbur...@virtuozzo.com> (cherry picked from vz7 commit 100feb098ab22c6b8b25861c3b2dfaa9c5db0b03) Signed-off-by: Konstantin Khorenko <khore...@virtuozzo.com> +++ ext4/balloon: Use proper O_ mode flags in balloon opening code alloc_file() expects O_* mode flags, so provide them, not internal FMODE_* ones. mFixes: bee340a206d7 ("ext4: Provide a balloon nipple for management") https://jira.sw.ru/browse/PSBM-129392 Signed-off-by: Konstantin Khorenko <khore...@virtuozzo.com> Reviewed-by: Kirill Tkhai <ktk...@virtuozzo.com> Signed-off-by: Kirill Tkhai <ktk...@virtuozzo.com> Feature: fs/ext4: fast online shrink support +++ ext4: Check alloc_file() results in ext4_open_balloon() Check for pointer validity before its dereference. Reported-by: Alexander Mikhalitsyn <alexander.mikhalit...@virtuozzo.com> Signed-off-by: Kirill Tkhai <ktk...@virtuozzo.com> Feature: fs/ext4: fast online shrink support --- fs/ext4/ext4.h | 1 + fs/ext4/ioctl.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++ fs/inode.c | 1 + 3 files changed, 62 insertions(+) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 807cd5cbe379..8dcee4361714 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -726,6 +726,7 @@ enum { #define EXT4_IOC_CLEAR_ES_CACHE _IO('f', 40) #define EXT4_IOC_GETSTATE _IOW('f', 41, __u32) #define EXT4_IOC_GET_ES_CACHE _IOWR('f', 42, struct fiemap) +#define EXT4_IOC_OPEN_BALLOON _IO('f', 42) #define EXT4_IOC_CHECKPOINT _IOW('f', 43, __u32) #define EXT4_IOC_MFSYNC _IO('f', 43) #define EXT4_IOC_GETFSUUID _IOR('f', 44, struct fsuuid) diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 73c57a66618a..08c5c053bf2d 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -1272,6 +1272,59 @@ static int ext4_mfsync(unsigned long arg) return err; } +static int ext4_open_balloon(struct super_block *sb, struct vfsmount *mnt) +{ + struct inode *balloon_ino; + int err, fd, ro; + struct file *filp; + struct dentry *de; + struct path path; + fmode_t mode; + + balloon_ino = EXT4_SB(sb)->s_balloon_ino; + err = -ENOENT; + if (balloon_ino == NULL) + goto err; + + err = fd = get_unused_fd_flags(0); + if (err < 0) + goto err_fd; + + __iget(balloon_ino); + de = d_obtain_alias(balloon_ino); + err = PTR_ERR(de); + if (IS_ERR(de)) + goto err_de; + + path.dentry = de; + path.mnt = mntget(mnt); + ro = mnt_want_write(path.mnt); + if (ro) + mode = O_RDONLY; + else + mode = O_RDWR; + filp = alloc_file(&path, mode, &ext4_file_operations); + if (!ro) + mnt_drop_write(path.mnt); + if (IS_ERR(filp)) { + err = PTR_ERR(filp); + goto err_filp; + } + + filp->f_flags |= O_LARGEFILE; + fd_install(fd, filp); + return fd; + +err_filp: + path_put(&path); +err_de: + put_unused_fd(fd); +err_fd: + /* nothing */ +err: + return err; +} + static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { struct inode *inode = file_inode(filp); @@ -1662,6 +1715,13 @@ static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) return ext4_ioctl_getuuid(EXT4_SB(sb), (void __user *)arg); case EXT4_IOC_SETFSUUID: return ext4_ioctl_setuuid(filp, (const void __user *)arg); + + case EXT4_IOC_OPEN_BALLOON: + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + return ext4_open_balloon(inode->i_sb, filp->f_path.mnt); + default: return -ENOTTY; } diff --git a/fs/inode.c b/fs/inode.c index 2e4dfa4bf06a..4846b61502e1 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -441,6 +441,7 @@ void __iget(struct inode *inode) { atomic_inc(&inode->i_count); } +EXPORT_SYMBOL(__iget); /* * get additional reference to inode; caller must already hold one. -- 2.43.5 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
