diff options
| -rw-r--r-- | fs/gfs2/ops_address.c | 74 |
1 files changed, 45 insertions, 29 deletions
diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c index d8d69a7..0118aa4 100644 --- a/fs/gfs2/ops_address.c +++ b/fs/gfs2/ops_address.c @@ -594,6 +594,36 @@ static void gfs2_invalidatepage(struct page *page, unsigned long offset) return; } +/** + * gfs2_ok_for_dio - check that dio is valid on this file + * @ip: The inode + * @rw: READ or WRITE + * @offset: The offset at which we are reading or writing + * + * Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o) + * 1 (to accept the i/o request) + */ +static int gfs2_ok_for_dio(struct gfs2_inode *ip, int rw, loff_t offset) +{ + /* + * Should we return an error here? I can't see that O_DIRECT for + * a journaled file makes any sense. For now we'll silently fall + * back to buffered I/O, likewise we do the same for stuffed + * files since they are (a) small and (b) unaligned. + */ + if (gfs2_is_jdata(ip)) + return 0; + + if (gfs2_is_stuffed(ip)) + return 0; + + if (offset > i_size_read(&ip->i_inode)) + return 0; + return 1; +} + + + static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t offset, unsigned long nr_segs) @@ -604,42 +634,28 @@ static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb, struct gfs2_holder gh; int rv; - if (rw == READ) - mutex_lock(&inode->i_mutex); /* - * Shared lock, even if its a write, since we do no allocation - * on this path. All we need change is atime. + * Deferred lock, even if its a write, since we do no allocation + * on this path. All we need change is atime, and this lock mode + * ensures that other nodes have flushed their buffered read caches + * (i.e. their page cache entries for this inode). We do not, + * unfortunately have the option of only flushing a range like + * the VFS does. */ - gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh); + gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, GL_ATIME, &gh); rv = gfs2_glock_nq_atime(&gh); if (rv) - goto out; - - if (offset > i_size_read(inode)) - goto out; - - /* - * Should we return an error here? I can't see that O_DIRECT for - * a journaled file makes any sense. For now we'll silently fall - * back to buffered I/O, likewise we do the same for stuffed - * files since they are (a) small and (b) unaligned. - */ - if (gfs2_is_jdata(ip)) - goto out; - - if (gfs2_is_stuffed(ip)) - goto out; - - rv = blockdev_direct_IO_own_locking(rw, iocb, inode, - inode->i_sb->s_bdev, - iov, offset, nr_segs, - gfs2_get_block_direct, NULL); + return rv; + rv = gfs2_ok_for_dio(ip, rw, offset); + if (rv != 1) + goto out; /* dio not valid, fall back to buffered i/o */ + + rv = blockdev_direct_IO_no_locking(rw, iocb, inode, inode->i_sb->s_bdev, + iov, offset, nr_segs, + gfs2_get_block_direct, NULL); out: gfs2_glock_dq_m(1, &gh); gfs2_holder_uninit(&gh); - if (rw == READ) - mutex_unlock(&inode->i_mutex); - return rv; } |