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Message-ID: <20241121135351.1230969-1-max.kellermann@ionos.com>
Date: Thu, 21 Nov 2024 14:53:51 +0100
From: Max Kellermann <max.kellermann@...os.com>
To: linux-nfs@...r.kernel.org,
trondmy@...nel.org,
anna@...nel.org
Cc: linux-kernel@...r.kernel.org,
Max Kellermann <max.kellermann@...os.com>
Subject: [PATCH] fs/nfs/io: make nfs_start_io_*() killable
This allows killing processes that wait for a lock when one process is
stuck waiting for the NFS server. This aims to complete the coverage
of NFS operations being killable, like nfs_direct_wait() does, for
example.
Signed-off-by: Max Kellermann <max.kellermann@...os.com>
---
fs/nfs/direct.c | 21 ++++++++++++++++++---
fs/nfs/file.c | 14 +++++++++++---
fs/nfs/internal.h | 7 ++++---
fs/nfs/io.c | 44 +++++++++++++++++++++++++++++++++-----------
4 files changed, 66 insertions(+), 20 deletions(-)
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 90079ca134dd..b08dbe96bc57 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -454,8 +454,16 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter,
if (user_backed_iter(iter))
dreq->flags = NFS_ODIRECT_SHOULD_DIRTY;
- if (!swap)
- nfs_start_io_direct(inode);
+ if (!swap) {
+ result = nfs_start_io_direct(inode);
+ if (result) {
+ /* release the reference that would usually be
+ * consumed by nfs_direct_read_schedule_iovec()
+ */
+ nfs_direct_req_release(dreq);
+ goto out_release;
+ }
+ }
NFS_I(inode)->read_io += count;
requested = nfs_direct_read_schedule_iovec(dreq, iter, iocb->ki_pos);
@@ -1007,7 +1015,14 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter,
requested = nfs_direct_write_schedule_iovec(dreq, iter, pos,
FLUSH_STABLE);
} else {
- nfs_start_io_direct(inode);
+ result = nfs_start_io_direct(inode);
+ if (result) {
+ /* release the reference that would usually be
+ * consumed by nfs_direct_write_schedule_iovec()
+ */
+ nfs_direct_req_release(dreq);
+ goto out_release;
+ }
requested = nfs_direct_write_schedule_iovec(dreq, iter, pos,
FLUSH_COND_STABLE);
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 6800ee92d742..1bb646752e46 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -166,7 +166,10 @@ nfs_file_read(struct kiocb *iocb, struct iov_iter *to)
iocb->ki_filp,
iov_iter_count(to), (unsigned long) iocb->ki_pos);
- nfs_start_io_read(inode);
+ result = nfs_start_io_read(inode);
+ if (result)
+ return result;
+
result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
if (!result) {
result = generic_file_read_iter(iocb, to);
@@ -187,7 +190,10 @@ nfs_file_splice_read(struct file *in, loff_t *ppos, struct pipe_inode_info *pipe
dprintk("NFS: splice_read(%pD2, %zu@...u)\n", in, len, *ppos);
- nfs_start_io_read(inode);
+ result = nfs_start_io_read(inode);
+ if (result)
+ return result;
+
result = nfs_revalidate_mapping(inode, in->f_mapping);
if (!result) {
result = filemap_splice_read(in, ppos, pipe, len, flags);
@@ -668,7 +674,9 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
nfs_clear_invalid_mapping(file->f_mapping);
since = filemap_sample_wb_err(file->f_mapping);
- nfs_start_io_write(inode);
+ error = nfs_start_io_write(inode);
+ if (error)
+ return error;
result = generic_write_checks(iocb, from);
if (result > 0)
result = generic_perform_write(iocb, from);
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 430733e3eff2..f0c9c7f51e77 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -6,6 +6,7 @@
#include "nfs4_fs.h"
#include <linux/fs_context.h>
#include <linux/security.h>
+#include <linux/compiler_attributes.h>
#include <linux/crc32.h>
#include <linux/sunrpc/addr.h>
#include <linux/nfs_page.h>
@@ -516,11 +517,11 @@ extern const struct netfs_request_ops nfs_netfs_ops;
#endif
/* io.c */
-extern void nfs_start_io_read(struct inode *inode);
+extern __must_check int nfs_start_io_read(struct inode *inode);
extern void nfs_end_io_read(struct inode *inode);
-extern void nfs_start_io_write(struct inode *inode);
+extern __must_check int nfs_start_io_write(struct inode *inode);
extern void nfs_end_io_write(struct inode *inode);
-extern void nfs_start_io_direct(struct inode *inode);
+extern __must_check int nfs_start_io_direct(struct inode *inode);
extern void nfs_end_io_direct(struct inode *inode);
static inline bool nfs_file_io_is_buffered(struct nfs_inode *nfsi)
diff --git a/fs/nfs/io.c b/fs/nfs/io.c
index b5551ed8f648..3388faf2acb9 100644
--- a/fs/nfs/io.c
+++ b/fs/nfs/io.c
@@ -39,19 +39,28 @@ static void nfs_block_o_direct(struct nfs_inode *nfsi, struct inode *inode)
* Note that buffered writes and truncates both take a write lock on
* inode->i_rwsem, meaning that those are serialised w.r.t. the reads.
*/
-void
+int
nfs_start_io_read(struct inode *inode)
{
struct nfs_inode *nfsi = NFS_I(inode);
+ int err;
+
/* Be an optimist! */
- down_read(&inode->i_rwsem);
+ err = down_read_killable(&inode->i_rwsem);
+ if (err)
+ return err;
if (test_bit(NFS_INO_ODIRECT, &nfsi->flags) == 0)
- return;
+ return 0;
up_read(&inode->i_rwsem);
+
/* Slow path.... */
- down_write(&inode->i_rwsem);
+ err = down_write_killable(&inode->i_rwsem);
+ if (err)
+ return err;
nfs_block_o_direct(nfsi, inode);
downgrade_write(&inode->i_rwsem);
+
+ return 0;
}
/**
@@ -74,11 +83,15 @@ nfs_end_io_read(struct inode *inode)
* Declare that a buffered read operation is about to start, and ensure
* that we block all direct I/O.
*/
-void
+int
nfs_start_io_write(struct inode *inode)
{
- down_write(&inode->i_rwsem);
- nfs_block_o_direct(NFS_I(inode), inode);
+ int err;
+
+ err = down_write_killable(&inode->i_rwsem);
+ if (!err)
+ nfs_block_o_direct(NFS_I(inode), inode);
+ return err;
}
/**
@@ -119,19 +132,28 @@ static void nfs_block_buffered(struct nfs_inode *nfsi, struct inode *inode)
* Note that buffered writes and truncates both take a write lock on
* inode->i_rwsem, meaning that those are serialised w.r.t. O_DIRECT.
*/
-void
+int
nfs_start_io_direct(struct inode *inode)
{
struct nfs_inode *nfsi = NFS_I(inode);
+ int err;
+
/* Be an optimist! */
- down_read(&inode->i_rwsem);
+ err = down_read_killable(&inode->i_rwsem);
+ if (err)
+ return err;
if (test_bit(NFS_INO_ODIRECT, &nfsi->flags) != 0)
- return;
+ return 0;
up_read(&inode->i_rwsem);
+
/* Slow path.... */
- down_write(&inode->i_rwsem);
+ err = down_write_killable(&inode->i_rwsem);
+ if (err)
+ return err;
nfs_block_buffered(nfsi, inode);
downgrade_write(&inode->i_rwsem);
+
+ return 0;
}
/**
--
2.45.2
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