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author | Steven Whitehouse <swhiteho@redhat.com> | 2006-02-14 14:54:42 +0300 |
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committer | Steven Whitehouse <swhiteho@redhat.com> | 2006-02-14 14:54:42 +0300 |
commit | d1665e414297c3a46fd80cb8242ad0c8e82acae7 (patch) | |
tree | 7cb19fc4cbfc21d6d890dd3b373d3854920862db /fs/gfs2/ops_address.c | |
parent | fc69d0d336214219abb521d8ff060f786d7f369e (diff) | |
download | linux-d1665e414297c3a46fd80cb8242ad0c8e82acae7.tar.xz |
[GFS2] Put back O_DIRECT support
This patch adds back O_DIRECT support with various caveats
attached:
1. Journaled data can be read via O_DIRECT since its now the
same on disk format as normal data files.
2. Journaled data writes with O_DIRECT will be failed sliently
back to normal writes (should we really do this I wonder or
should we return an error instead?)
3. Stuffed files will be failed back to normal buffered I/O
4. All the usual corner cases (write beyond current end of file,
write to an unallocated block) will also revert to normal buffered I/O.
The I/O path is slightly odd as reads arrive at the page cache layer
with the lock for the file already held, but writes arrive unlocked.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Diffstat (limited to 'fs/gfs2/ops_address.c')
-rw-r--r-- | fs/gfs2/ops_address.c | 72 |
1 files changed, 58 insertions, 14 deletions
diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c index b14357e89421..74706f352780 100644 --- a/fs/gfs2/ops_address.c +++ b/fs/gfs2/ops_address.c @@ -14,6 +14,7 @@ #include <linux/buffer_head.h> #include <linux/pagemap.h> #include <linux/mpage.h> +#include <linux/fs.h> #include <asm/semaphore.h> #include "gfs2.h" @@ -555,30 +556,73 @@ static int gfs2_invalidatepage(struct page *page, unsigned long offset) return ret; } -static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, - loff_t offset, unsigned long nr_segs) +static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov, + loff_t offset, unsigned long nr_segs) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + struct gfs2_inode *ip = get_v2ip(inode); + struct gfs2_holder gh; + int rv; + + /* + * Shared lock, even though its write, since we do no allocation + * on this path. All we need change is atime. + */ + gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh); + rv = gfs2_glock_nq_m_atime(1, &gh); + if (rv) + 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(WRITE, iocb, inode, inode->i_sb->s_bdev, + iov, offset, nr_segs, get_blocks_noalloc, + NULL, DIO_OWN_LOCKING); +out: + gfs2_glock_dq_m(1, &gh); + gfs2_holder_uninit(&gh); + + return rv; +} + +/** + * gfs2_direct_IO + * + * This is called with a shared lock already held for the read path. + * Currently, no locks are held when the write path is called. + */ +static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb, + const struct iovec *iov, loff_t offset, + unsigned long nr_segs) { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; struct gfs2_inode *ip = get_v2ip(inode); struct gfs2_sbd *sdp = ip->i_sbd; - get_blocks_t *gb = get_blocks; atomic_inc(&sdp->sd_ops_address); - if (gfs2_is_jdata(ip)) - return -EINVAL; + if (rw == WRITE) + return gfs2_direct_IO_write(iocb, iov, offset, nr_segs); - if (rw == WRITE) { - return -EOPNOTSUPP; /* for now */ - } else { - if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)) || - gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip))) - return -EINVAL; - } + if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)) || + gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip))) + return -EINVAL; - return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, - offset, nr_segs, gb, NULL); + return __blockdev_direct_IO(READ, iocb, inode, inode->i_sb->s_bdev, iov, + offset, nr_segs, get_blocks, NULL, + DIO_OWN_LOCKING); } struct address_space_operations gfs2_file_aops = { |