[PATCH 20/23] vfs: Teach aio to use file_hotplug_lock

Eric W. Biederman
2009-06-01T21:57:23Z

From: Eric W. Biederman <ebiederm@maxwell.aristanetworks.com>

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
---
fs/aio.c | 51 ++++++++++++++++++++++++++++++++++++++-------------
1 files changed, 38 insertions(+), 13 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 76da125..eceb215 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1362,13 +1362,20 @@ static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
{
struct file *file = iocb->ki_filp;
- struct address_space *mapping = file->f_mapping;
- struct inode *inode = mapping->host;
+ struct address_space *mapping;
+ struct inode *inode;
ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
unsigned long, loff_t);
ssize_t ret = 0;
unsigned short opcode;

+ ret = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out;
+
+ mapping = file->f_mapping;
+ inode = mapping->host;
+
if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
(iocb->ki_opcode == IOCB_CMD_PREAD)) {
rw_op = file->f_op->aio_read;
@@ -1379,8 +1386,9 @@ static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
}

/* This matches the pread()/pwrite() logic */
+ ret = -EINVAL;
if (iocb->ki_pos < 0)
- return -EINVAL;
+ goto out_unlock;

do {
ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
@@ -1407,26 +1415,37 @@ static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
&& iocb->ki_nbytes - iocb->ki_left)
ret = iocb->ki_nbytes - iocb->ki_left;

+out_unlock:
+ file_hotplug_read_unlock(file);
+out:
return ret;
}

static ssize_t aio_fdsync(struct kiocb *iocb)
{
struct file *file = iocb->ki_filp;
- ssize_t ret = -EINVAL;
+ ssize_t ret = -EIO;

- if (file->f_op->aio_fsync)
- ret = file->f_op->aio_fsync(iocb, 1);
+ if (file_hotplug_read_trylock(file)) {
+ ret = -EINVAL;
+ if (file->f_op->aio_fsync)
+ ret = file->f_op->aio_fsync(iocb, 1);
+ file_hotplug_read_unlock(file);
+ }
return ret;
}

static ssize_t aio_fsync(struct kiocb *iocb)
{
struct file *file = iocb->ki_filp;
- ssize_t ret = -EINVAL;
+ ssize_t ret = -EIO;

- if (file->f_op->aio_fsync)
- ret = file->f_op->aio_fsync(iocb, 0);
+ if (file_hotplug_read_trylock(file)) {
+ ret = -EINVAL;
+ if (file->f_op->aio_fsync)
+ ret = file->f_op->aio_fsync(iocb, 0);
+ file_hotplug_read_unlock(file);
+ }
return ret;
}

@@ -1469,7 +1488,11 @@ static ssize_t aio_setup_single_vector(struct kiocb *kiocb)
static ssize_t aio_setup_iocb(struct kiocb *kiocb)
{
struct file *file = kiocb->ki_filp;
- ssize_t ret = 0;
+ ssize_t ret;
+
+ ret = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out;

switch (kiocb->ki_opcode) {
case IOCB_CMD_PREAD:
@@ -1551,10 +1574,12 @@ static ssize_t aio_setup_iocb(struct kiocb *kiocb)
ret = -EINVAL;
}

- if (!kiocb->ki_retry)
- return ret;
+ if (kiocb->ki_retry)
+ ret = 0;

- return 0;
+ file_hotplug_read_unlock(file);
+out:
+ return ret;
}

/*
--
1.6.3.1.54.g99dd.dirty