diff options
| author | kib <kib@FreeBSD.org> | 2012-07-02 21:01:03 +0000 |
|---|---|---|
| committer | kib <kib@FreeBSD.org> | 2012-07-02 21:01:03 +0000 |
| commit | 53224f018aac13056c11af9d1233317b1754149c (patch) | |
| tree | 26c1ae1ac3dde3bf8b9b01fad04caad427a4ef48 /sys/fs/devfs | |
| parent | 293bf50336e246390039b341f229e30d00d97d27 (diff) | |
| download | FreeBSD-src-53224f018aac13056c11af9d1233317b1754149c.zip FreeBSD-src-53224f018aac13056c11af9d1233317b1754149c.tar.gz | |
Extend the KPI to lock and unlock f_offset member of struct file. It
now fully encapsulates all accesses to f_offset, and extends f_offset
locking to other consumers that need it, in particular, to lseek() and
variants of getdirentries().
Ensure that on 32bit architectures f_offset, which is 64bit quantity,
always read and written under the mtxpool protection. This fixes
apparently easy to trigger race when parallel lseek()s or lseek() and
read/write could destroy file offset.
The already broken ABI emulations, including iBCS and SysV, are not
converted (yet).
Tested by: pho
No objections from: jhb
MFC after: 3 weeks
Diffstat (limited to 'sys/fs/devfs')
| -rw-r--r-- | sys/fs/devfs/devfs_vnops.c | 15 |
1 files changed, 4 insertions, 11 deletions
diff --git a/sys/fs/devfs/devfs_vnops.c b/sys/fs/devfs/devfs_vnops.c index 4a58a42..d3e6cf5 100644 --- a/sys/fs/devfs/devfs_vnops.c +++ b/sys/fs/devfs/devfs_vnops.c @@ -1170,18 +1170,14 @@ devfs_read_f(struct file *fp, struct uio *uio, struct ucred *cred, int flags, st if (ioflag & O_DIRECT) ioflag |= IO_DIRECT; - if ((flags & FOF_OFFSET) == 0) - uio->uio_offset = fp->f_offset; - + foffset_lock_uio(fp, uio, flags | FOF_NOLOCK); error = dsw->d_read(dev, uio, ioflag); if (uio->uio_resid != resid || (error == 0 && resid != 0)) vfs_timestamp(&dev->si_atime); td->td_fpop = fpop; dev_relthread(dev, ref); - if ((flags & FOF_OFFSET) == 0) - fp->f_offset = uio->uio_offset; - fp->f_nextoff = uio->uio_offset; + foffset_unlock_uio(fp, uio, flags | FOF_NOLOCK | FOF_NEXTOFF); return (error); } @@ -1648,8 +1644,7 @@ devfs_write_f(struct file *fp, struct uio *uio, struct ucred *cred, int flags, s ioflag = fp->f_flag & (O_NONBLOCK | O_DIRECT | O_FSYNC); if (ioflag & O_DIRECT) ioflag |= IO_DIRECT; - if ((flags & FOF_OFFSET) == 0) - uio->uio_offset = fp->f_offset; + foffset_lock_uio(fp, uio, flags | FOF_NOLOCK); resid = uio->uio_resid; @@ -1661,9 +1656,7 @@ devfs_write_f(struct file *fp, struct uio *uio, struct ucred *cred, int flags, s td->td_fpop = fpop; dev_relthread(dev, ref); - if ((flags & FOF_OFFSET) == 0) - fp->f_offset = uio->uio_offset; - fp->f_nextoff = uio->uio_offset; + foffset_unlock_uio(fp, uio, flags | FOF_NOLOCK | FOF_NEXTOFF); return (error); } |
