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-rw-r--r--fs/ocfs2/file.c86
1 files changed, 62 insertions, 24 deletions
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 581eb45..a9559c8 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -613,7 +613,8 @@ leave:
/* Some parts of this taken from generic_cont_expand, which turned out
* to be too fragile to do exactly what we need without us having to
- * worry about recursive locking in ->commit_write(). */
+ * worry about recursive locking in ->prepare_write() and
+ * ->commit_write(). */
static int ocfs2_write_zero_page(struct inode *inode,
u64 size)
{
@@ -641,7 +642,7 @@ static int ocfs2_write_zero_page(struct inode *inode,
goto out;
}
- ret = ocfs2_prepare_write(NULL, page, offset, offset);
+ ret = ocfs2_prepare_write_nolock(inode, page, offset, offset);
if (ret < 0) {
mlog_errno(ret);
goto out_unlock;
@@ -695,13 +696,26 @@ out:
return ret;
}
+/*
+ * A tail_to_skip value > 0 indicates that we're being called from
+ * ocfs2_file_aio_write(). This has the following implications:
+ *
+ * - we don't want to update i_size
+ * - di_bh will be NULL, which is fine because it's only used in the
+ * case where we want to update i_size.
+ * - ocfs2_zero_extend() will then only be filling the hole created
+ * between i_size and the start of the write.
+ */
static int ocfs2_extend_file(struct inode *inode,
struct buffer_head *di_bh,
- u64 new_i_size)
+ u64 new_i_size,
+ size_t tail_to_skip)
{
int ret = 0;
u32 clusters_to_add;
+ BUG_ON(!tail_to_skip && !di_bh);
+
/* setattr sometimes calls us like this. */
if (new_i_size == 0)
goto out;
@@ -714,27 +728,44 @@ static int ocfs2_extend_file(struct inode *inode,
OCFS2_I(inode)->ip_clusters;
if (clusters_to_add) {
- ret = ocfs2_extend_allocation(inode, clusters_to_add);
+ /*
+ * protect the pages that ocfs2_zero_extend is going to
+ * be pulling into the page cache.. we do this before the
+ * metadata extend so that we don't get into the situation
+ * where we've extended the metadata but can't get the data
+ * lock to zero.
+ */
+ ret = ocfs2_data_lock(inode, 1);
if (ret < 0) {
mlog_errno(ret);
goto out;
}
- ret = ocfs2_zero_extend(inode, new_i_size);
+ ret = ocfs2_extend_allocation(inode, clusters_to_add);
if (ret < 0) {
mlog_errno(ret);
- goto out;
+ goto out_unlock;
}
- }
- /* No allocation required, we just use this helper to
- * do a trivial update of i_size. */
- ret = ocfs2_simple_size_update(inode, di_bh, new_i_size);
- if (ret < 0) {
- mlog_errno(ret);
- goto out;
+ ret = ocfs2_zero_extend(inode, (u64)new_i_size - tail_to_skip);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto out_unlock;
+ }
+ }
+
+ if (!tail_to_skip) {
+ /* We're being called from ocfs2_setattr() which wants
+ * us to update i_size */
+ ret = ocfs2_simple_size_update(inode, di_bh, new_i_size);
+ if (ret < 0)
+ mlog_errno(ret);
}
+out_unlock:
+ if (clusters_to_add) /* this is the only case in which we lock */
+ ocfs2_data_unlock(inode, 1);
+
out:
return ret;
}
@@ -793,7 +824,7 @@ int ocfs2_setattr(struct dentry *dentry, struct iattr *attr)
if (i_size_read(inode) > attr->ia_size)
status = ocfs2_truncate_file(inode, bh, attr->ia_size);
else
- status = ocfs2_extend_file(inode, bh, attr->ia_size);
+ status = ocfs2_extend_file(inode, bh, attr->ia_size, 0);
if (status < 0) {
if (status != -ENOSPC)
mlog_errno(status);
@@ -1049,21 +1080,12 @@ static ssize_t ocfs2_file_aio_write(struct kiocb *iocb,
if (!clusters)
break;
- ret = ocfs2_extend_allocation(inode, clusters);
+ ret = ocfs2_extend_file(inode, NULL, newsize, count);
if (ret < 0) {
if (ret != -ENOSPC)
mlog_errno(ret);
goto out;
}
-
- /* Fill any holes which would've been created by this
- * write. If we're O_APPEND, this will wind up
- * (correctly) being a noop. */
- ret = ocfs2_zero_extend(inode, (u64) newsize - count);
- if (ret < 0) {
- mlog_errno(ret);
- goto out;
- }
break;
}
@@ -1146,6 +1168,22 @@ static ssize_t ocfs2_file_aio_read(struct kiocb *iocb,
ocfs2_iocb_set_rw_locked(iocb);
}
+ /*
+ * We're fine letting folks race truncates and extending
+ * writes with read across the cluster, just like they can
+ * locally. Hence no rw_lock during read.
+ *
+ * Take and drop the meta data lock to update inode fields
+ * like i_size. This allows the checks down below
+ * generic_file_aio_read() a chance of actually working.
+ */
+ ret = ocfs2_meta_lock(inode, NULL, NULL, 0);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto bail;
+ }
+ ocfs2_meta_unlock(inode, 0);
+
ret = generic_file_aio_read(iocb, buf, count, iocb->ki_pos);
if (ret == -EINVAL)
mlog(ML_ERROR, "generic_file_aio_read returned -EINVAL\n");
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