diff options
Diffstat (limited to 'fs/xfs/xfs_exchrange.c')
| -rw-r--r-- | fs/xfs/xfs_exchrange.c | 143 |
1 files changed, 142 insertions, 1 deletions
diff --git a/fs/xfs/xfs_exchrange.c b/fs/xfs/xfs_exchrange.c index c8a655c92c92..d0889190ab7f 100644 --- a/fs/xfs/xfs_exchrange.c +++ b/fs/xfs/xfs_exchrange.c @@ -72,6 +72,34 @@ xfs_exchrange_estimate( return error; } +/* + * Check that file2's metadata agree with the snapshot that we took for the + * range commit request. + * + * This should be called after the filesystem has locked /all/ inode metadata + * against modification. + */ +STATIC int +xfs_exchrange_check_freshness( + const struct xfs_exchrange *fxr, + struct xfs_inode *ip2) +{ + struct inode *inode2 = VFS_I(ip2); + struct timespec64 ctime = inode_get_ctime(inode2); + struct timespec64 mtime = inode_get_mtime(inode2); + + trace_xfs_exchrange_freshness(fxr, ip2); + + /* Check that file2 hasn't otherwise been modified. */ + if (fxr->file2_ino != ip2->i_ino || + fxr->file2_gen != inode2->i_generation || + !timespec64_equal(&fxr->file2_ctime, &ctime) || + !timespec64_equal(&fxr->file2_mtime, &mtime)) + return -EBUSY; + + return 0; +} + #define QRETRY_IP1 (0x1) #define QRETRY_IP2 (0x2) @@ -607,6 +635,12 @@ xfs_exchrange_prep( if (error || fxr->length == 0) return error; + if (fxr->flags & __XFS_EXCHANGE_RANGE_CHECK_FRESH2) { + error = xfs_exchrange_check_freshness(fxr, ip2); + if (error) + return error; + } + /* Attach dquots to both inodes before changing block maps. */ error = xfs_qm_dqattach(ip2); if (error) @@ -719,7 +753,8 @@ xfs_exchange_range( if (fxr->file1->f_path.mnt != fxr->file2->f_path.mnt) return -EXDEV; - if (fxr->flags & ~XFS_EXCHANGE_RANGE_ALL_FLAGS) + if (fxr->flags & ~(XFS_EXCHANGE_RANGE_ALL_FLAGS | + __XFS_EXCHANGE_RANGE_CHECK_FRESH2)) return -EINVAL; /* Userspace requests only honored for regular files. */ @@ -802,3 +837,109 @@ xfs_ioc_exchange_range( fdput(file1); return error; } + +/* Opaque freshness blob for XFS_IOC_COMMIT_RANGE */ +struct xfs_commit_range_fresh { + xfs_fsid_t fsid; /* m_fixedfsid */ + __u64 file2_ino; /* inode number */ + __s64 file2_mtime; /* modification time */ + __s64 file2_ctime; /* change time */ + __s32 file2_mtime_nsec; /* mod time, nsec */ + __s32 file2_ctime_nsec; /* change time, nsec */ + __u32 file2_gen; /* inode generation */ + __u32 magic; /* zero */ +}; +#define XCR_FRESH_MAGIC 0x444F524B /* DORK */ + +/* Set up a commitrange operation by sampling file2's write-related attrs */ +long +xfs_ioc_start_commit( + struct file *file, + struct xfs_commit_range __user *argp) +{ + struct xfs_commit_range args = { }; + struct timespec64 ts; + struct xfs_commit_range_fresh *kern_f; + struct xfs_commit_range_fresh __user *user_f; + struct inode *inode2 = file_inode(file); + struct xfs_inode *ip2 = XFS_I(inode2); + const unsigned int lockflags = XFS_IOLOCK_SHARED | + XFS_MMAPLOCK_SHARED | + XFS_ILOCK_SHARED; + + BUILD_BUG_ON(sizeof(struct xfs_commit_range_fresh) != + sizeof(args.file2_freshness)); + + kern_f = (struct xfs_commit_range_fresh *)&args.file2_freshness; + + memcpy(&kern_f->fsid, ip2->i_mount->m_fixedfsid, sizeof(xfs_fsid_t)); + + xfs_ilock(ip2, lockflags); + ts = inode_get_ctime(inode2); + kern_f->file2_ctime = ts.tv_sec; + kern_f->file2_ctime_nsec = ts.tv_nsec; + ts = inode_get_mtime(inode2); + kern_f->file2_mtime = ts.tv_sec; + kern_f->file2_mtime_nsec = ts.tv_nsec; + kern_f->file2_ino = ip2->i_ino; + kern_f->file2_gen = inode2->i_generation; + kern_f->magic = XCR_FRESH_MAGIC; + xfs_iunlock(ip2, lockflags); + + user_f = (struct xfs_commit_range_fresh __user *)&argp->file2_freshness; + if (copy_to_user(user_f, kern_f, sizeof(*kern_f))) + return -EFAULT; + + return 0; +} + +/* + * Exchange file1 and file2 contents if file2 has not been written since the + * start commit operation. + */ +long +xfs_ioc_commit_range( + struct file *file, + struct xfs_commit_range __user *argp) +{ + struct xfs_exchrange fxr = { + .file2 = file, + }; + struct xfs_commit_range args; + struct xfs_commit_range_fresh *kern_f; + struct xfs_inode *ip2 = XFS_I(file_inode(file)); + struct xfs_mount *mp = ip2->i_mount; + struct fd file1; + int error; + + kern_f = (struct xfs_commit_range_fresh *)&args.file2_freshness; + + if (copy_from_user(&args, argp, sizeof(args))) + return -EFAULT; + if (args.flags & ~XFS_EXCHANGE_RANGE_ALL_FLAGS) + return -EINVAL; + if (kern_f->magic != XCR_FRESH_MAGIC) + return -EBUSY; + if (memcmp(&kern_f->fsid, mp->m_fixedfsid, sizeof(xfs_fsid_t))) + return -EBUSY; + + fxr.file1_offset = args.file1_offset; + fxr.file2_offset = args.file2_offset; + fxr.length = args.length; + fxr.flags = args.flags | __XFS_EXCHANGE_RANGE_CHECK_FRESH2; + fxr.file2_ino = kern_f->file2_ino; + fxr.file2_gen = kern_f->file2_gen; + fxr.file2_mtime.tv_sec = kern_f->file2_mtime; + fxr.file2_mtime.tv_nsec = kern_f->file2_mtime_nsec; + fxr.file2_ctime.tv_sec = kern_f->file2_ctime; + fxr.file2_ctime.tv_nsec = kern_f->file2_ctime_nsec; + + file1 = fdget(args.file1_fd); + if (!file1.file) + return -EBADF; + fxr.file1 = file1.file; + + error = xfs_exchange_range(&fxr); + fdput(file1); + return error; +} |