ceph: make ceph_start_io_*() killable

This allows killing processes that wait for a lock when one process is
stuck waiting for the Ceph server.  This is similar to the NFS commit
38a125b31504 ("fs/nfs/io: make nfs_start_io_*() killable").

[ idryomov: drop comment on include, formatting ]

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 978acd3d4b329c3d768acd819b6f210367ba6c68..08681cf661375d46750e552e2bd97af5163140fb 100644 (file)
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -2121,10 +2121,10 @@ again:
        if (ceph_inode_is_shutdown(inode))
                return -ESTALE;
 
-       if (direct_lock)
-               ceph_start_io_direct(inode);
-       else
-               ceph_start_io_read(inode);
+       ret = direct_lock ? ceph_start_io_direct(inode) :
+                           ceph_start_io_read(inode);
+       if (ret)
+               return ret;
 
        if (!(fi->flags & CEPH_F_SYNC) && !direct_lock)
                want |= CEPH_CAP_FILE_CACHE;
@@ -2277,7 +2277,9 @@ static ssize_t ceph_splice_read(struct file *in, loff_t *ppos,
            (fi->flags & CEPH_F_SYNC))
                return copy_splice_read(in, ppos, pipe, len, flags);
 
-       ceph_start_io_read(inode);
+       ret = ceph_start_io_read(inode);
+       if (ret)
+               return ret;
 
        want = CEPH_CAP_FILE_CACHE;
        if (fi->fmode & CEPH_FILE_MODE_LAZY)
@@ -2356,10 +2358,10 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
                direct_lock = true;
 
 retry_snap:
-       if (direct_lock)
-               ceph_start_io_direct(inode);
-       else
-               ceph_start_io_write(inode);
+       err = direct_lock ? ceph_start_io_direct(inode) :
+                           ceph_start_io_write(inode);
+       if (err)
+               goto out_unlocked;
 
        if (iocb->ki_flags & IOCB_APPEND) {
                err = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE, false);

diff --git a/fs/ceph/io.c b/fs/ceph/io.c
index c456509b31c3f88e3c98244de7904816c6e160f0..e10f44182a4cbffe0c409063de73808a8d5cdc73 100644 (file)
--- a/fs/ceph/io.c
+++ b/fs/ceph/io.c
@@ -47,20 +47,29 @@ static void ceph_block_o_direct(struct ceph_inode_info *ci, 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
-ceph_start_io_read(struct inode *inode)
+int ceph_start_io_read(struct inode *inode)
 {
        struct ceph_inode_info *ci = ceph_inode(inode);
+       int err;
 
        /* Be an optimist! */
-       down_read(&inode->i_rwsem);
+       err = down_read_killable(&inode->i_rwsem);
+       if (err)
+               return err;
+
        if (!(READ_ONCE(ci->i_ceph_flags) & CEPH_I_ODIRECT))
-               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;
+
        ceph_block_o_direct(ci, inode);
        downgrade_write(&inode->i_rwsem);
+
+       return 0;
 }
 
 /**
@@ -83,11 +92,12 @@ ceph_end_io_read(struct inode *inode)
  * Declare that a buffered write operation is about to start, and ensure
  * that we block all direct I/O.
  */
-void
-ceph_start_io_write(struct inode *inode)
+int ceph_start_io_write(struct inode *inode)
 {
-       down_write(&inode->i_rwsem);
-       ceph_block_o_direct(ceph_inode(inode), inode);
+       int err = down_write_killable(&inode->i_rwsem);
+       if (!err)
+               ceph_block_o_direct(ceph_inode(inode), inode);
+       return err;
 }
 
 /**
@@ -133,20 +143,29 @@ static void ceph_block_buffered(struct ceph_inode_info *ci, 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
-ceph_start_io_direct(struct inode *inode)
+int ceph_start_io_direct(struct inode *inode)
 {
        struct ceph_inode_info *ci = ceph_inode(inode);
+       int err;
 
        /* Be an optimist! */
-       down_read(&inode->i_rwsem);
+       err = down_read_killable(&inode->i_rwsem);
+       if (err)
+               return err;
+
        if (READ_ONCE(ci->i_ceph_flags) & CEPH_I_ODIRECT)
-               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;
+
        ceph_block_buffered(ci, inode);
        downgrade_write(&inode->i_rwsem);
+
+       return 0;
 }
 
 /**

diff --git a/fs/ceph/io.h b/fs/ceph/io.h
index fa594cd77348ac7bc2acdc8ddc37b8d1c7ce9b22..79029825e8b820a4fe53527c6b9e3955c27c6562 100644 (file)
--- a/fs/ceph/io.h
+++ b/fs/ceph/io.h
@@ -2,11 +2,13 @@
 #ifndef _FS_CEPH_IO_H
 #define _FS_CEPH_IO_H
 
-void ceph_start_io_read(struct inode *inode);
+#include <linux/compiler_attributes.h>
+
+int __must_check ceph_start_io_read(struct inode *inode);
 void ceph_end_io_read(struct inode *inode);
-void ceph_start_io_write(struct inode *inode);
+int __must_check ceph_start_io_write(struct inode *inode);
 void ceph_end_io_write(struct inode *inode);
-void ceph_start_io_direct(struct inode *inode);
+int __must_check ceph_start_io_direct(struct inode *inode);
 void ceph_end_io_direct(struct inode *inode);
 
 #endif /* FS_CEPH_IO_H */