git: 43e7448343dd - stable/15 - fusefs: better handling for low-memory conditions

The branch stable/15 has been updated by asomers:

URL: https://cgit.FreeBSD.org/src/commit/?id=43e7448343ddfc487e8899c3b3e7582b5618da4d

commit 43e7448343ddfc487e8899c3b3e7582b5618da4d
Author:     Alan Somers <asomers@FreeBSD.org>
AuthorDate: 2026-03-30 14:22:07 +0000
Commit:     Alan Somers <asomers@FreeBSD.org>
CommitDate: 2026-04-27 19:37:59 +0000

    fusefs: better handling for low-memory conditions
    
    Under conditions of low memory, getblk can fail.  fusefs was not
    handling those failures very systematically.  It was always using
    PCATCH, which appears to have been originally copy/pasted from the NFS
    client code, but isn't always appropriate:
    
    * During fuse_vnode_setsize_immediate, which can be called from many
      different VOPs and from the vn_delayed_setsize mechanism, remove
      PCATCH.  Some of these callers cannot tolerate allocate failure.
    
    * In fuse_inval_buf_range, don't assume that getblk will always succeed.
    
    * When calling fuse_inval_buf_range from VOP_ALLOCATE,
      VOP_COPY_FILE_RANGE, or VOP_WRITE (with IO_DIRECT), return EINTR if
      the allocation fails.
    
    * When calling fuse_inval_buf_range from VOP_DEALLOCATE, remove PCATCH.
      This VOP must not fail with EINTR.
    
    No new tests, because I can't force any particular getblk call to fail.
    
    PR:             293957
    Sponsored by:   ConnectWise
    Reported by:    zjk7@wp.pl
    
    (cherry picked from commit 374548e930bd9452351059c14e697036d903b1c4)
---
 sys/fs/fuse/fuse_node.c  |  6 +-----
 sys/fs/fuse/fuse_vnops.c | 24 +++++++++++++++++-------
 2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/sys/fs/fuse/fuse_node.c b/sys/fs/fuse/fuse_node.c
index f4fb993a7ca1..6768e87fdef1 100644
--- a/sys/fs/fuse/fuse_node.c
+++ b/sys/fs/fuse/fuse_node.c
@@ -506,11 +506,7 @@ fuse_vnode_setsize_immediate(struct vnode *vp, bool shrink)
 		 */
 
 		lbn = newsize / iosize;
-		bp = getblk(vp, lbn, iosize, PCATCH, 0, 0);
-		if (!bp) {
-			err = EINTR;
-			goto out;
-		}
+		bp = getblk(vp, lbn, iosize, 0, 0, 0);
 		if (!(bp->b_flags & B_CACHE))
 			goto out;	/* Nothing to do */
 		MPASS(bp->b_flags & B_VMIO);
diff --git a/sys/fs/fuse/fuse_vnops.c b/sys/fs/fuse/fuse_vnops.c
index 80db04a25166..43a0d2de0d1a 100644
--- a/sys/fs/fuse/fuse_vnops.c
+++ b/sys/fs/fuse/fuse_vnops.c
@@ -326,7 +326,8 @@ fuse_fifo_close(struct vop_close_args *ap)
 
 /* Invalidate a range of cached data, whether dirty of not */
 static int
-fuse_inval_buf_range(struct vnode *vp, off_t filesize, off_t start, off_t end)
+fuse_inval_buf_range(struct vnode *vp, off_t filesize, off_t start, off_t end,
+	int slpflag)
 {
 	struct buf *bp;
 	daddr_t left_lbn, end_lbn, right_lbn;
@@ -338,7 +339,9 @@ fuse_inval_buf_range(struct vnode *vp, off_t filesize, off_t start, off_t end)
 	end_lbn = howmany(end, iosize);
 	left_on = start & (iosize - 1);
 	if (left_on != 0) {
-		bp = getblk(vp, left_lbn, iosize, PCATCH, 0, 0);
+		bp = getblk(vp, left_lbn, iosize, slpflag, 0, 0);
+		if (!bp)
+			return (EINTR);
 		if ((bp->b_flags & B_CACHE) != 0 && bp->b_dirtyend >= left_on) {
 			/*
 			 * Flush the dirty buffer, because we don't have a
@@ -357,7 +360,9 @@ fuse_inval_buf_range(struct vnode *vp, off_t filesize, off_t start, off_t end)
 		right_lbn = end / iosize;
 		new_filesize = MAX(filesize, end);
 		right_blksize = MIN(iosize, new_filesize - iosize * right_lbn);
-		bp = getblk(vp, right_lbn, right_blksize, PCATCH, 0, 0);
+		bp = getblk(vp, right_lbn, right_blksize, slpflag, 0, 0);
+		if (!bp)
+			return (EINTR);
 		if ((bp->b_flags & B_CACHE) != 0 && bp->b_dirtyoff < right_on) {
 			/*
 			 * Flush the dirty buffer, because we don't have a
@@ -647,7 +652,10 @@ fuse_vnop_allocate(struct vop_allocate_args *ap)
 	err = fuse_vnode_size(vp, &filesize, cred, curthread);
 	if (err)
 		return (err);
-	fuse_inval_buf_range(vp, filesize, *offset, *offset + *len);
+	err = fuse_inval_buf_range(vp, filesize, *offset, *offset + *len,
+	    PCATCH);
+	if (err)
+		return (err);
 
 	fdisp_init(&fdi, sizeof(*ffi));
 	fdisp_make_vp(&fdi, FUSE_FALLOCATE, vp, curthread, cred);
@@ -941,7 +949,7 @@ fuse_vnop_copy_file_range(struct vop_copy_file_range_args *ap)
 
 	vnode_pager_clean_sync(invp);
 	err = fuse_inval_buf_range(outvp, outfilesize, *ap->a_outoffp,
-		*ap->a_outoffp + io.uio_resid);
+		*ap->a_outoffp + io.uio_resid, PCATCH);
 	if (err)
 		goto unlock;
 
@@ -2589,7 +2597,7 @@ fuse_vnop_write(struct vop_write_args *ap)
 		end = start + uio->uio_resid;
 		if (!pages) {
 			err = fuse_inval_buf_range(vp, filesize, start,
-			    end);
+			    end, PCATCH);
 			if (err)
 				goto out;
 		}
@@ -3123,7 +3131,9 @@ fuse_vnop_deallocate(struct vop_deallocate_args *ap)
 	err = fuse_vnode_size(vp, &filesize, cred, curthread);
 	if (err)
 		goto out;
-	fuse_inval_buf_range(vp, filesize, *offset, *offset + *len);
+	err = fuse_inval_buf_range(vp, filesize, *offset, *offset + *len, 0);
+	if (err)
+		goto out;
 
 	fdisp_init(&fdi, sizeof(*ffi));
 	fdisp_make_vp(&fdi, FUSE_FALLOCATE, vp, curthread, cred);