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Fuse allows the value of a symlink to change and this property is exploited by some filesystems (e.g. CVMFS). It has been observed, that sometimes after changing the symlink contents, the value is truncated to the old size. This is caused by fuse_getattr() racing with fuse_reverse_inval_inode(). fuse_reverse_inval_inode() updates the fuse_inode's attr_version, which results in fuse_change_attributes() exiting before updating the cached attributes This is okay, as the cached attributes remain invalid and the next call to fuse_change_attributes() will likely update the inode with the correct values. The reason this causes problems is that cached symlinks will be returned through page_get_link(), which truncates the symlink to inode->i_size. This is correct for filesystems that don't mutate symlinks, but in this case it causes bad behavior. The solution is to just remove this truncation. This can cause a regression in a filesystem that relies on supplying a symlink larger than the file size, but this is unlikely. If that happens we'd need to make this behavior conditional. Reported-by: Laura Promberger <laura.promberger@cern.ch> Tested-by: Sam Lewis <samclewis@google.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Link: https://lore.kernel.org/r/20250220100258.793363-1-mszeredi@redhat.com Reviewed-by: Bernd Schubert <bschubert@ddn.com> Signed-off-by: Christian Brauner <brauner@kernel.org> |
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| .. | ||
| acl.c | ||
| control.c | ||
| cuse.c | ||
| dax.c | ||
| dev_uring_i.h | ||
| dev_uring.c | ||
| dev.c | ||
| dir.c | ||
| file.c | ||
| fuse_dev_i.h | ||
| fuse_i.h | ||
| fuse_trace.h | ||
| inode.c | ||
| ioctl.c | ||
| iomode.c | ||
| Kconfig | ||
| Makefile | ||
| passthrough.c | ||
| readdir.c | ||
| sysctl.c | ||
| virtio_fs.c | ||
| xattr.c | ||